The objective of this study was to assess the primary stability and the osseointegration process in implants with different macrostructures  in rabbit tibiae. Twenty-four (24) rabbits were used, divided into 3 experimental periods  with 8 animals each. Each animal bilaterally received 2 implants from each group in the tibial metaphysis: Cylindrical Implant (CI) and Hybrid Conical Implant (HCI). All implants were assessed for insertion torque. After the experimental periods, one of the implants in each group was submitted to the removal counter-torque test and descriptive histological analysis while the other implant was used for microtomographic and histometric analysis (%Bone-Implant Contact). HCI implants showed higher insertion torque (32.93 ± 10.61 Ncm vs. 27.99 ± 7.80 Ncm) and higher % of bone-implant contact in the 8-week period (79.08 ± 11.31% vs. 59.72 ± 11.29%) than CI implants. However, CI implants showed higher values of removal counter-torque than HCI implants in the 8-week period (91.05 ± 9.32 Ncm vs. 68.62 ± 13.70 Ncm). There were no differences between groups regarding microtomographic data. It can be concluded that HCI implants showed greater insertion torque and bone-implant contact in relation to CI implants in the period of 8 weeks when installed in cortical bone of rabbits. The use of osseointegrated dental implants in the treatment of partial or total edentulism has been a widely used procedure in recent years ,2. HowevIn this context, a series of changes in the implant design and surgical techniques have been introduced to improve bone-implant contact, anchorage and stress distribution ,8,9. ManTherefore, these structural modifications of the implants can be performed at the nano- or micro-structure level ,11,12, aConsidering that changes in the implant macrostructure have been reported as important for obtaining primary stability of implants in areas with poor quality bone, such as in the posterior region of the maxilla , studies®, Grand Morse, Curitiba, Brazil) compared to a control implant  in the process of osseointegration in cortical bone  of rabbits.Consequently, that the macrostructure is an extremely important characteristic for obtaining primary stability, a parameter related to the success of the implant osseointegration, changes in the implant macrostructure have been proposed in order to improve the initial locking of the implants. Thus, the objective of this study was to verify the influence of an experimental implant with perforating compacting macrostructure  of the Faculty of Dentistry of Araraquara (FOAr-UNESP) (11/2016). For the present research, 24 male New Zealand albino rabbits (~5 months old and 4–5 kg) were used. The animals were kept in an environment with a temperature of 22–24 °C, with a controlled light cycle (12 h light and 12 h dark) and consumption of solid food and water ad libitum throughout the experimental period. The study was conducted according to the ARRIVE protocol.The 24 rabbits were randomly divided into 3 experimental periods . Each animal bilaterally received two implants from each group in the cortical bone of the animals’ tibia, with the side selected at random. Two different macrostructures were assessed: Hybrid Conical Implant (HCI) and Cylindrical Implant (CI).The CI implant used in this study is characterized by a cervical diameter equal to the diameter of the implant body (3.75 mm in diameter × 11 mm in height). Presence of triangular and double threads that facilitate the quick implant insertion, with minimal trauma, and apex morphology with the presence of self-cutting chambers A,C,E. Th®, Agener União Ltd.a, São Paulo, SP, Brazil—0.35 mg/kg) and xylazine . Subsequently, trichotomy and antisepsis were performed with 10% iodinated polyvinylpyrrolidone (IPVP) with 1% active iodine in the right and left portions of the tibial metaphysis of the animal , using metal drills under abundant refrigeration with sterile saline solution  and non-resorbable thread   and analgesic . After the periods of 2, 4 and 8 weeks, the animals were euthanized through anesthetic overdose.The animals were initially weighed and anesthetized intramuscularly, with a combination of ketamine  K,L. AfteAll installed implants were submitted to the assessment of the insertion torque, and for that, the torque was noted after the installation of the implants (at the bone level). After euthanasia, in each analysis period , the medial portions of the samples obtained from the tibia were reopened to expose the implants and perform the reverse torque. The samples were stabilized in a small vise, and a hexagonal wrench was connected to both the implant and the torque wrench , and an anti-clockwise movement was performed to remove the implants, increasing the torque until the rotation of the implant occurred inside the bone tissue, completely disrupting the bone-implant interface, when the torque wrench registered the maximum torque peak necessary for this disruption. This maximum peak required to move the implant was noted as the removal torque value. The remnants of the tibia related to the upper implants that were previously removed for the removal torque analysis were then reduced and immersed in 10% formaldehyde for 48 h, washed in running water for 4 h and then decalcified in Ethylenediaminetetraacetic Acid (E.D.T.A. 7%) for two months.After the decalcification period, the parts from the sites where the implants were removed for analysis of the removal torque were embedded in paraffin, cut into a microtome (6 µm-thick) and stained using the hematoxylin-eosin (HE) technique. Five slides were obtained with 3 sections each in the central region of the site where the implant was inserted. Three sections were assessed that were 36 µm apart, and the first section for assessment was selected randomly. The sections were assessed by means of a DIASTAR optical microscope  with 5× and 10× magnifications, and the quality of bone tissue in the vicinity of the implant bed was assessed. This analysis was performed by an experienced trained examiner, blind for the type of implant used.The parts from the sites where the implants were kept , after the fixation process with 4% formaldehyde for 48 h and washing with running water for 4 h, were dehydrated in an alcohol solution. Subsequently, they were subjected to the scanning process through the μCT and the following parameters were used: the size of the pixel image was 2000 × 1336 (18 μm), the thickness of the sections was 12 μm, the magnification of the image was 10×, the voltage of the X-ray tube was 50 kV, the beam was 496 μA, and the electrical current was adjusted to 0.1 mA. The three-dimensional images were reconstructed using a reconstruction software . The parameters for reconstruction were: Beam Hardening Correction = 4%, Ring Artifact Correction = 3, Smoothing = 1, Postalignment = 1.00. Subsequently, the scanned images were reoriented in three planes  to standardize the position before performing the volumetric analysis. The measurements for the Volumetric analysis (3D) were carried out using specific software , following the selection of an area of interest (ROI—region of interest) in a cylindrical shape that circumscribed in 0.5 cm the diameter of the implants. Although the implants received a cover screw, there was bone formation inside the cover screw in some cases. In order to prevent this bone formation from interfering with the analysis of the volume of mineralized tissue around the implant, a second ROI was established to remove the volume of mineralized tissues that could have been formed in this region. With the results obtained in the two ROI’s, it was possible to define the volume of mineralized tissues using the following formula:Total bone volume of mineralized tissues in the main ROI—Volume of mineralized tissues within the cover screw = Volume of mineralized tissues (BV/TV).The grayscale threshold used was 25–90, and the values of the volume of mineralized tissue around the implant were obtained as a percentage. The entire analysis was performed by a single trained examiner, who was blind for the type of training performed .The biopsies with the lower implants that were submitted to the fixation process and microtomographic analysis were subsequently dehydrated in an alcohol solution in a series of increasing concentrations. The plastic infiltration was performed with mixtures of glycolmethacrylate (Technovit 7200 VLC) and ethyl alcohol, following gradual variations, ending with two infiltrations of pure glycol methacrylate. After plastic infiltration, the specimens were embedded in resin and polymerized. Therefore, the specimens were sectioned longitudinally, along the main axis of the implant, using a high precision diamond disk. The blocks were mounted on an acrylic slide with the help of Tecnovit 4000 resin . Using a cutting and micro-wear system , the blades were processed with a section of approximately 50–70 μm thick. The pieces were stained with Stevenel’s Blue for histomorphometric analysis. Histometry assessed the percentage of mineralized bone in direct contact with the implant surface (BIC—bone to implant contact) in the extension of the cervical third of the implant. The measurements were made using a DIASTAR optical microscope , with a 10-fold magnification objective lens, through which the images were captured and sent to a PC, with the aid of a video camera . The values were determined using image analysis software , by a blind examiner, calibrated and trained for this analysis .%BIC = Direct contact of the bone with the implant surface × 100/Extension of the cervical third of the implant.The data from the biomechanical , microtomographic (BV/TV) and histometric (%BIC) analyses were submitted to the Shapiro-Wilk normality test which confirmed that the data were distributed according to the central distribution theorem. The parametric paired t-test was used for the inferential analysis of the data comparing the different groups of macrostructures (CI vs. HCI). The One-way ANOVA test was applied to compare the different assessment periods within each group. The GraphPad Prism 6 software  was employed in the statistical tests that were applied at the significance level of 5%. Sample calculation was performed using the paired t-test based on the histometric data of bone-implant contact from the study by Faeda et al. 2012 , which aThe animals tolerated well the surgical procedure and remained healthy throughout the experimental period.It was found that the HCI implants had a higher insertion torque than the CI implants. There was a progressive increase in implant removal torques in all groups, regardless of the type of macrostructure assessed. It was found that the CIs presented higher removal torque than HCIs in the period of 8 weeks. There were no differences between groups regarding the BV/TV data. However, there was a progressive increase in this parameter with the increase in the time of the experimental periods in both groups. The histological description was performed in decalcified sections in the region associated with the first thread of the implants. There were no differences in the histological aspects of bone tissue associated with the different macrostructures of the implants, thus, this description was performed together, varying only the description of the different experimental periods.At two weeks, it was possible to observe the formation of new bone in the region of the threads that presented a trabecular aspect with rounded osteocytes, immature mineralized matrix without organization in the form of concentric lamellae, active osteoblasts with intense organization of the formation of Haversian channels and presence of medullary tissue. At 4 weeks, it was observed an increase in the formation of the mineralized matrix associated with a change in the appearance of the matrix to a more organized condition with the formation of concentric lamellae and a reduction in the number and diameter of the Haversian channels. There was also a reduction in medullary tissue, presence of rounded osteocytes in large numbers and a lower number of osteoblasts. The appearance of peri-implant bone tissue has changed little over the 8-week period compared to the 4-week period. The presence of a mineralized matrix was observed in an advanced stage of mineralization, with the presence of well-defined Haversian channels, presence of rounded osteocytes, organization of the mineralized matrix in concentric lamellae and reduced amount of medullary tissue .It was found that HCI implants (79.08 ± 11.31%) had a higher %BIC in the 8-week period compared to CI implants (59.72 ± 11.29%). In general, in this study, it was found that HCI implants showed better primary stability, which consequently resulted in greater bone-implant contact at the end of the 8 weeks of assessment, which demonstrates that this type of macrostructure can clinically receive occlusal loads earlier, be used in bones of lower density and accelerate the osseointegration process when compared to CI implants.It has been determined that the implant macrostructure promotes changes in terms of obtaining primary stability ,23. The Conflicting data in this study was that the removal torque of CI implants was higher than that of HCI implants in the period of 8 weeks. A factor that could have interfered with this aspect would be that the higher insertion torque of the HCI implants would have induced greater necrosis of the cortical bone tissue and delayed the osseointegration process ,28. HoweIt has also been reported in the literature that primary stability is essential for the osseointegration process to occur in a predictable way and that the degree of osseointegration is correlated with the quality of this stability ,31,32, aThe results of this study should be interpreted with caution because, in addition to the limitations mentioned above, this model cannot extrapolate clinical conditions such as the application of immediate or early loading, which could alter the osseointegration process in these implants. In addition, the bicortical locking offered by the tibia of rabbits, which in fact helps in the primary stability of implants, is not a common event to be expected in daily clinical practice, where implants usually lock in their most coronal portion in the cortical bone of the maxilla or the mandible. Thus, the effect of HCI on osseointegration still requires further investigation.According to the results from and within the limits of this study, it is observed that HCI Implants showed greater insertion torque and bone-implant contact in relation to CI implants in the period of 8 weeks when installed in cortical bone of rabbits. However, the removal torque of CI implants was higher than that of HCI implants in the period of 8 weeks.


To compare the diagnostic accuracy of a low-cost screening test for identifying children at risk for language disorders with that of a specific language assessment.The study was conducted during a polio vaccination campaign in basic health units in western São Paulo, Brazil. The parents/guardians of 1000 children aged between 0 and 5 years were asked to answer questions of a specific screening test. The instrument consisted of a uniform set of questions about the main milestones in language development (from 0 to 5 years of age) with scaled scores to assess responses. There were no exclusion criteria. After the screening test, the children were referred to a specific language assessment by ABFW, following a determined flow of referrals. The results obtained in the screening were compared to those obtained in the specific language assessment; then, the sensitivity, specificity, accuracy, and positive and negative predictive values were determined for the screening test. Children who failed the screening test also underwent an audiological evaluation. The statistical significance was set at 5%.The majority of the participants were aged between 4 and 5 years (21.82%) and were male (51.6%). The sensitivity and specificity values were 82.5% and 98.93%, respectively. The area under the curve was 0.907 (0.887–0.925), and the screening test showed 96% accuracy.The screening test showed high diagnostic efficiency in determining the risk of language disorders in children aged between 0 and 5 years. Knowledge on the prevalence, incidence, and risk factors of a particular disease in the community is important for health professionals and managers to allocate sufficient resources for managing the problems associated with that disease and to design and implement health promotion and disease prevention strategies Regarding epidemiological studies, the SLHS literature shows that speech-language delay and language disorders are the most common developmental difficulties in childhood Considering that between 40% and 60% of language disorders go untreated and the negative effects of language impairment on an individual's social development and education Konning et al. A study conducted in Brazil investigated the risk factors of language disorders in children aged between 0 and 5 years through a specific survey and conducted follow-up with a screening test for communication disorders A recent literature review that investigated the predictive validity of preschool screening tools for language and/or behavioral difficulties indicated that the language development surveys administered at 2 years of age achieved the best predictive validity, with 67% sensitivity, 94% specificity, 88% negative predictive value, and 80% positive predictive value There are some limitations to the studies that proposed population surveys as screening instruments, such as a generalized and superficial view of language development, low levels of sensitivity, specific focus on understanding and expressive language skills, and the use of sample populations with a small number of participants and no diversity in age groups Recent studies suggest that there is insufficient scientific evidence on the effectiveness of screening tests and speech-language assessments for children aged up to 5 years without suspected disorders It is important to consider the evidence that indicates the benefit of including a specific language-screening instrument in routine screening performed at child health centers; this can lead to early detection of language delay, enabling informed referrals to specialist services and early intervention Therefore, the objective of this study was to compare the diagnostic accuracy of a low-cost screening test for identifying children at risk for language disorders with that of a specific gold standard language assessment.This study was approved by the research ethics committee of the School of Medicine at the University of São Paulo  (CAPPesq HCFMUSP 387/10).The study was conducted during a polio vaccination campaign in basic health units in western São Paulo, Brazil. The parents/guardians of 1,000 children aged between 0 and 5 years were asked to answer the questions of a specific screening test. The children's parents/guardians who agreed to participate were asked to sign an informed consent form. There were no exclusion criteria.The study was conducted with 1,000 children aged between 0 and 5 years living in the micro-region Butantã/Jaguaré in the municipality of São Paulo, Brazil, and treated in health centers located in western São Paulo during a vaccination campaign.The instrument used in the present study was a screening test for language disorders developed and validated by the ASHA After obtaining the ASHA's formal license, the process of translation and back-translation of the protocol was initiated, according to the requirement of standardization of the test and guidelines for the process of cross-cultural adaptation  To check the reliability of the translated questions and their format, a bilingual speech-language pathologist (fluent both in Portuguese and English) performed the back-translation of the questionnaire (English to Portuguese). Both versions were compared to ensure their equivalence. In the back-translated version, the translator carried out further adaptations for vocabulary, syntactic issues, and expressions and then compared it to the published English version. The shortcomings and errors were corrected, and the first draft was prepared.The first draft was sent to a committee  that thoroughly evaluated the first version of the screening test for simplicity of the text, grammar, and use of proper terms and syntax. Four steps of equivalence, namely semantic, idiomatic, experiential, and conceptual equivalence, were evaluated for cross-cultural adaptation Finally, the judges examined the committee's considerations, accepting pertinent suggestions and elaborating the final version to be used in the pre-test. The pre-test involved ten participants with different levels of education, from complete primary school to graduate degree. The participants were asked to read, paraphrase, and comment on their understanding of the instructions, items, and response options of the instrument. Based on their responses, no further modification was needed.We used face-to-face interviews for data collection to avoid selection bias related to illiterate participants and to reduce the number of non-respondents. All participants were interviewed by a trained interviewer individually. To assess test-retest reliability, 30 patients completed the screening over 2 weeks; the procedure was conducted by the same interviewer.Cronbach's alpha and intraclass correlation coefficient (ICC) were used to determine the reliability of the screening; the Cronbach's alpha coefficient was ≤0.7 and the ICC was ≥0.85.The screening process examined the main developmental milestones across the language domain using age-specific questions. The participants were divided into the following age groups according to the ASHA criteria - Group I: 0 to 3 months- Group II: 4 to 6 months- Group III: 7 months to 1 year- Group IV: 1 year and 1 month to 2 years- Group V: 2 years and 1 month to 3 years- Group VI: 3 years and 1 month to 4 years- Group VII: 4 years and 1 month to 5 years and 11 months.The answer options for each screening question were “no,” “yes,” or “no answer” (when the child parent/guardian was unsure about the answer). Each answer was scored as per the ASHA criteria in the original version of the screening protocol .Each interview lasted between 5 and 15 minutes. At the end of the screening process, each participant was informed of his/her final score, which was the sum of the scores obtained for each question.All children who underwent the screening test were referred to a specific speech-language assessment in the school-clinic of the undergraduate speech therapy program of the School of Medicine at the University of São Paulo (FMUSP).The speech-language assessment was performed using the ABFW test A standardized test validated for use in Brazilian Portuguese-speaking children does not exist, and the ABFW test The data were recorded using individual protocols and on video and analyzed by two speech-language pathologists (SLPs) specializing in speech-language assessment. They received specific training in analyzing the results of the ABFW test. The SLPs were blinded to the study objectives. Data analysis was completed in 2 months after screening and within a maximum of 2 weeks after the language assessment. Children who presented altered parameters for at least one of the four areas covered by the ABFW test were considered as to present with language development disorders.Children who failed the screening test, independently of the results in the language assessment, also underwent a comprehensive audiological evaluation using audiometry and immitanciometry. Children who had a hearing threshold of up to 15 dB HL for all tested frequencies (250 to 8000 Hz), type A tympanogram curve, and showed acoustic reflex were considered to have normal hearing t-test, at a significance level of 5%.Data on the age and sex composition of the sample were analyzed using Student's The specificity and sensitivity of the instrument were determined based on the relationship between the answers obtained by the screening instrument and the results of the specific speech-language assessment (gold standard criteria).In accordance with the definitions proposed by Agresti The positive predictive value (PPV) was based on the ratio between the number of true positives (TP) and the sum of TP and false positives (FP), where PPV=TP/TP+FP. The negative predictive value (NPV) was calculated based on the ratio between the number of true negatives (TN) and the sum of TP and false negatives (FN), where NPV=TN/TN+FN.Accuracy (A) was calculated based on the ratio between the sum of VP and VN and the total number of cases analyzed in the study (N), where A=TP+TN/N. The area under the receiver operating characteristic (ROC) curve was also calculated.The likelihood ratio for positive test results (PLR) was calculated based on the ratio between sensitivity (S) and one minus specificity (E), where PLR=S/1-E, while the likelihood ratio for negative test results (NLR) was calculated based on the ratio between one minus sensitivity and specificity, where NLR=1-S/E.Associação Brasileira de Empresas de PesquisaFor the analysis of sociodemographic factors of children who failed the language assessment , the criteria established by the The study included 1000 children: 516 boys (51.6%) and 484 girls (48.82%). p<0.009).The 4–5-year age group had a larger number of participants than the other groups. This difference was statistically significant  is presented in The sensitivity and specificity values, predictive value, and AUC (0.907 [0.887–0.925]) value may be considered high and satisfactory The PLR and NLR were 77 and 0.18, respectively. The fact that the PLR value was greater than 1 and the NLR value was very close to 0 indicates a high likelihood of the instrument identifying true positives and negatives .Using the same screening tool in a population with high disease prevalence increases its positive predictive value. Conversely, increased prevalence results in a decreased NPV. All participants who underwent an audiological evaluation presented a hearing threshold that fell within normal limits (as per criteria described in the methods section).The sociodemographic characterization of the 120 children who failed the language assessment is presented in The screening instrument tested in this study showed high sensitivity (82.5%) and specificity 98,93%) and high AUC (0.90) for detecting the risk of language delay in children aged between 0 and 5 years. An international validation study on a widely used language-screening protocol for children aged between 18 and 24 months showed that the test sensitivity ranged between 24% and 52% (acceptable) and that the specificity ranged between 97% and 98% (high) 8,93% andThe sample comprised more male children than female children. This difference was statistically significant in the 1–2-years age group. The 2–3-years age group was the only group where there were more girls than boys. This difference was statistically significant. The results also show that more boys failed the test than girls. This difference was statistically significant, corroborating the findings of previous studies where the prevalence of the risk of communication disorders was found to be greater among boys than among girls The 4–5-years age group had a larger number of participants than the other groups. This difference was shown to be statistically significant. International studies have reported that the prevalence of language delay and/or language disorders among children aged between 2 and 5 years ranges between 2.4% and 12% A comparison of the results of the present study with the findings of previous studies suggests that the predominance of participants aged between 4 and 5 years in the sample may reflect difficulties in the early detection of problems in children at risk of or children with language delay in the region in which the study was undertaken. Hence, there is an urgent need to evaluate suitable screening instruments and promote the wider use of validated tests from the early stages of child development to minimize the risks of language delay We found an estimated prevalence rate of language delay/disorder of 11% in the screening and a true prevalence rate of 12.5% by the gold criteria. The median prevalence of receptive language delay/disorder ranged from 2.63% to 3.59%, that of expressive language delay/disorder ranged from 2.81% to 16%, and that of combined receptive and expressive language delay/disorder ranged from 2.02% to 3.01% Of note, the reasons for this variability in the prevalence of speech and language disorders include the definition of what constitutes a case, the severity and type of communication disorder that is included in the definition, the nature of the surveyed population, and differences in methodological procedures Studies suggest that questionnaires offer an effective, rapid, and low-cost method for determining the prevalence of a given disorder in large groups The adherence rate among individuals referred for comprehensive assessment was high, particularly among children who failed the screening test, thus contributing to high levels of sensitivity and specificity. One of the factors that may have contributed to the loss of participants in this stage of the study was the distance between the medical center and the patient's home and the resulting cost and traveling time required to undertake the assessment, which has been shown to affect adherence to follow-up health care Another limitation of this study is that the speech and language assessment used in this study was not a national or international gold standard protocol. However, a gold standard protocol for detecting speech and language disorders in Brazilian Portuguese speaking children does not exist. The lack of a gold standard protocol for this type of evaluation is a limiting factor in the development of effective screening tools for the detection of language delay in children Our findings show that the screening test proposed in this study has high sensitivity  and specificity  for detecting the risk of language delay in children aged between 0 and 5 years. The true prevalence was 12.47%. The screening test is an easy-to-use, rapid, low-cost method for screening large numbers of children in primary health care settings.Further research with larger samples consisting of children from different regions of Brazil and involving the adaptation of the instrument for use in children who speak other languages is recommended to determine the level of sensitivity and specificity of the instrument and generalizability of the results.Dias DC was responsible for the acquisition and analysis of data, drafting of the manuscript and literature review. Rondon-Melo S provided substantial contribution to the analysis and interpretation of data and final draft of the manuscript. Molini-Avejonas DR was responsible for the manuscript concept and design, acquisition, analysis, and interpretation of data, manuscript drafting, critically review for important intellectual content and approval of the final manuscript version.


To study the roots of tomato plants cultivar Belyi Naliv and FeSOD-transgenic line, we examined the distribution of reactive oxygen species and immunodetection of α-tubulin. The differences in the microtubules cortical network between wild type and transgenic plants without salinity were detected. The differences were found in the cortical network of microtubules between control and transgenic plants in the absence of salt stress. While an ordered microtubule network was revealed in the root cells of wild type tomato, no such degree of ordering was detected in transgenic line cells. The signs of microtubule disorganization in root cells of wild type plants were manifested under the NaCl and Na2SO4 treatment. On the contrary, the cytoskeleton structural organization in the transgenic line cells was more ordered. In addition, the formation of atypical tubulin polymers was observed in response to salt stress. Changes in cell size, due to both vacuolization and impaired cell expansion in columella zone and cap initials, were responsible for the root tip tissue modification.We analyzed the morphological changes in root tip cells caused by the application of iso-osmotic NaCl and Na2SO4 solutions to tomato plants harboring an introduced superoxide dismutase gene. To study the roots of tomato plants cultivar Belyi Naliv (WT) and FeSOD-transgenic line, we examined the distribution of ROS and enzyme-linked immunosorbent detection of α-tubulin. In addition, longitudinal sections of the root apexes were compared. Transmission electronic microscopy of atypical cytoskeleton structures was also performed. The differences in the microtubules cortical network between WT and transgenic plants without salt stress were detected. The differences were found in the cortical network of microtubules between WT and transgenic plants in the absence of salt stress. While an ordered microtubule network was revealed in the root cells of WT tomato, no such degree of ordering was detected in transgenic line cells. The signs of microtubule disorganization in root cells of WT plants were manifested under the NaCl treatment. On the contrary, the cytoskeleton structural organization in the transgenic line cells was more ordered. Similar changes, including the cortical microtubules disorganization, possibly associated with the formation of atypical tubulin polymers as a response to salt stress caused by Na2SO4 treatment, were also observed. Changes in cell size, due to both vacuolization and impaired cell expansion in columella zone and cap initials, were responsible for the root tip tissue modification.Various abiotic stresses cause the appearance of reactive oxygen species (ROS) in plant cells, which seriously damage the cellular structures. The engineering of transgenic plants with higher production of ROS-scavenging enzyme in plant cells could protect the integrity of such a fine intracellular structure as the cytoskeleton and each cellular compartment. We analyzed the morphological changes in root tip cells caused by the application of iso-osmotic NaCl and Na Plant protection from the damaging effects of oxidative stress is an urgent problem of plant physiology and biotechnology. Many abiotic and biotic factors cause a stress response in plants, during which the production level of reactive oxygen species (ROS) in cells increases, causing a state of oxidative stress . The difMethods of modern biotechnology have enhanced the plant’s protection from stress by introducing genes encoding different components of the antioxidant defense system. Thus, an increase in resistance to oxidative stress was demonstrated in transgenic plants with overexpression of foreign genes encoding superoxide dismutase, ascorbate peroxidase, and glutathione reductase . However2+ content and is accompanied by the production of abscisic acid, is one of the ways to form a cellular response to a stress factor [The role of ROS as molecular regulators of plant signaling systems under the onset of salt stress action, which, when elevated, causes changes in phospholipids and Cas factor ,7.+/H+-antiporter), SOS2 (serine-threonine protein kinase 8), SOS3  [Arabidopsis thaliana L., an increase in the SOS1 expression [sos1 and sos2 Arabidopsis mutants, it was shown that impaired expression and protein synthesis of the SOS system can cause disorders of the cell cytoskeleton and, consequently, root structure [+ can be the main effector of cortical microtubules depolymerization, the inclusion of the SOS protective system, which is responsible for the removal of Na+ ions, leads to the restoration of the cell cytoskeleton structure, although in an altered form, nonetheless capable of supporting cell division and expansion. It is well known that during salinization, osmotic stress, which uses its specific signaling and response mechanisms, has the same damaging effect as the toxic factor conditioned by harmful ions [It has been suggested that the key response of cells to the toxic effects of salts is to maintain ionic homeostasis by removing toxic ions . Varioustein p8) . Thus, ipression  with a dpression  in epidepression . For thetructure . It is aful ions . It was ful ions , but ledful ions ,16, alfaful ions , and tomful ions .The modification of the cytoskeleton caused by salinity is accompanied by thinning of the network and thickening of microtubule bundles, which is shown for both osmotic and salt effects ,17. The 2O2). In turn, peroxide is neutralized by other intracellular enzymes  to such a harmless compound as water. Chloroplasts are at greatest risk of oxygen toxicity because the molecular oxygen present in photosystem I gains an extra electron and is converted to superoxide by photoreduction. Superoxide dismutase within chloroplasts plays an important role in the prevention of photosynthetic disturbances caused by oxidative damage [Arabidopsis thaliana genome contains seven SOD genes , differing in location of expression product [Plants use three types of superoxide dismutase  in the primary protection of cells from ROS damage. The main function of these enzymes is the enzymatic conversion of such a highly toxic molecule for cells as superoxide into hydrogen peroxide .In our work, we analyzed the structural state of the cells and tissues of the root apex, tubulin cytoskeleton in cells of the roots of the tomato original cv Belyi Naliv and its transgenic line 19 expressing the Solanum lycopersicum L.) plants of the control cultivar Belyi Naliv (Wild Type) and transgenic line 19 expressing the superoxide dismutase FeSOD gene from Arabidopsis thaliana (L.) Heynh. [−2 s−1, and air humidity of 60–70%. Then, the plants were placed on ½ MC medium with the addition of salt solutions (99 mM NaCl and 87 mM Na2SO4) in iso-osmotic (‒0.4 MPa) concentration, and cultivated for 7 days under the same temperature/light/humidity conditions. The concentration was chosen based on the results of preliminary experiments as caused by a strong delay in seedling growth [The in vitro cultivated tomato  Heynh.  were theg growth . After tThe tomato root tip (4–5 mm) of all in vitro cultivated samples of control and FeSOD-trangenic line 19 7-days-after were separated and placed on a glass slide in a drop of water. We used an aqueous solution of Carboxy-H2DFFDA  for intravital ROS visualization in cells, at a concentration of 25–50 nM after 30 min incubation time. The stained pieces were washed three times with sterile water.Intravital root preparations were analyzed using an Olympus BX51 fluorescence microscope , with magnification ×10, at a wavelength of 490 nm. Images were obtained using a Color View II digital camera .To analyze the structural organization of the tubulin cytoskeleton in root cells, the tomato plants root tips of control and transgenic line grown in conditions without salt addition and under the action of salts were used.Root tips (4 mm) after 7 days cultivation in salinity imitating conditions were cut off for fixation. The detached fragments were fixed in a freshly prepared solution of para-formaldehyde  on a PHEM buffer  for 2 h at room temperature. The fixator was removed by 2× washing in a PHEM buffer. For maceration, the root pieces were treated with a solution of 2% cellulase in a Na-acetate buffer (pH 5.0), and then the samples were transferred to a PHEM buffer. Next, the roots were transferred on a coverslip in a buffer drop and split to separate cells with metal needles. Then the samples were dried for 24 h in a refrigerator at 4 °C.Preparations were washed with PHEM-buffer. Next, a drop of PHEM-buffer containing 0.5% Triton X-100 and 5% DMSO was applied to the sample, and then a preparation was incubated in 5% goat serum for 30 min to block non-specific binding to antibodies. The first antibodies used were murine monoclonal antibodies to tubulin DM1α  at a dilution of 1: 200 in 10 mM Tris buffer (pH 7.6) with the addition of 0.1% BSA for 16 h at 20 °C. After washing twice in 10 mM Tris buffer (pH 7.6) and 20 mM Tris buffer (pH 8.2), the preparations were incubated with second goat antibodies to mouse IgG conjugated with Alexa-488  in dilution 1:400 for 45 min at 37 °C. To reveal the nuclei, the prepared preparations were stained with DAPI , then mounted in Moviol 4–88 . The preparations were placed in a 4 °C refrigerator and assessed under an Axiovert 200M microscope  with a Neofluar 100/1.24x objective under epifluorescence illumination with a set of filters . For immunocytochemical and electron microscopic studies, meristematic cells from the central zone of root apex belonged to the interphase (G1-S) of the cell cycle were used. Images of each cell were obtained in several optical sections (at the level of the nucleus and the level of the edge of the cell) using an AxioCam HRm digital camera and processed in Adobe Photoshop 7.0.For ultrastructural analysis, plant root tips up to 3 mm long were separated. Samples were fixed in a 2.5% glutaraldehyde solution in 0.1 M Sorensen phosphate buffer (pH 7.2) with the addition of 1.5% sucrose. After washing from the fixing mixture, the samples were post-fixed with a 1.0% solution of osmium tetroxide (OsO4), dehydrated in ethanol with increasing concentration , propylene oxide and encapsulated with Epon–Araldit epoxy resins. Semi-thin and ultra-thin sections were prepared using the LKB–III ultramicrotome. Sections were contrasted with a 1% aqueous solution of uranyl acetate and lead citrate accordingly Reinolds, and analyzed at ×15,000 magnification using an H-500 transmission electron microscope . Images were processed in Adobe Photoshop 7.0.Statistical analysis of the dates was performed using Fisher’s and Duncan’s tests with the program AGROS (version 2.11). To estimate the average number of columella cell layers, we used 50 transverse sections of root tips from 5 independent plants for each variants.2SO4 caused a significant increase in cell density both in the cap and in the meristematic zone and root initials.The root tips of the tomato plants cv Belyi Naliv (WT) and the transgenic line 19 obtained on this variety basis corresponded to the type of structural organization typical for tomatoes . They ha2SO4 treatments were accompanied by a redistribution of the cytoplasmic compartment, a more chaotic arrangement of vacuoles and a decrease in their size under application of both salts. It seemed that Na2SO4 had been causing some cytoplasm compaction and cell wall thickening , which coincide with the auxins modification and sugars transport . A changickening . FeSOD-tickening d. The ced or not d–f. In o2SO4 caused the earlier vacuolization of cells, and if NaCl did not prevent the fusion of vacuoles into one large vacuole, then the smaller vacuoles were observed under the Na2SO4, the uniform distribution of organelles in old  cells was preserved, and the formation of a central vacuole was blocked. The features of the fusion of vacuoles are probably of separate interest. The acceleration of the vacuole fusion process could be observed in columella cells in plants of the FeSOD-transgenic line cultivated without salinity. In this case, the displacement of the organelles and nucleus to the cell periphery was observed already in the second or third layer situated distally from the initials. Cell arrangement did not have the proper degree of ordering of the gradual location from the initials to the periphery, which is probably caused by the consequences of a disturbance in division and expansion processes. An orderliness of the layers and a gradual increase in cell size were maintained under NaCl and Na2SO4 treatments. However, the location of organelles, nuclei, and vacuoles in the cells differed significantly from layer to layer, and from row to row. Apparently, this can be explained by a violation of the membrane fusion processes, division of compartments, and, probably, restrictions on the movement of the cytoplasm. Such perturbations associated with the dynamic transformation of the cytoskeleton are well studied and are related to impaired osmotic homeostasis [Cells in the zone of the cap’s initials, adjacent to the root meristematic zone, were characterized by the central location of the nucleus and had several small vacuoles beginning to form under without stressful conditions. The cells had a regular rectangular shape. They are arranged in rows one above the other, and the farther the cell is from the initials, the more it increases in width and, it seems, contains only one central vacuole in the fourth layer from the meristem. The nucleus and cytoplasmic organelles are shifted to the periphery of the cells and are located along the cell walls, while in older layers, large columella cells contain starch-filled statoliths and the nucleus in the upper part of cells. Presumably, NaCl and Naeostasis ,31.Staining the roots of tomato plants with a fluorescent dye on ROS production showed that the ROS were detected in all root tissues upon salinity stress, however, the staining intensity varied in cells from different zones. Since not all root zones were equally stained for ROS, we estimated the distribution of cells with an increased level of ROS production in different zones of the roots . Root zo2SO4 stress in the root tip cells from WT and FeSOD-transgenic line 19 tomato plants using immunocytochemistry and TEM.The cytoskeleton is one of the targets for ROS ,33. The 2SO4 treatment  causes certain rearrangements of microtubules (tubulin cytoskeleton) of plants: (1) disturbance of the ordered organization of the cortical network microtubule such as chaotization, change in orientation relative to the growth axis; possibly, this is the reason for the formation of microtubule converging centers, although it cannot be ruled out that such centers indicate the initiation of the growth for new microtubules; (2) network becomes less dense, possibly due to the depolymerization of the microtubule sub-population; (3) formation of thick and dense bundles; (4) appearance of fragmented and shortened microtubules bundles. When comparing the response to the salinity of the microtubule system in the plant roots of WT and FeSOD-transgenic line tomato plants, it was found that this response of microtubules in the root cells of WT tomato to such an abiotic factor as salinity was manifested in different variants of disorganization. Transgenic line 19 initially had an abnormal microtubule system, but upon salt exposure, partial phenotypic “recovery” occurred that was manifested in an increased number of bundles and the formation of cortical networks (both ordered and chaotic). A number of studies have suggested that when the ROS homeostasis in cells changes, the tubulin cytoskeleton passes into another structural state by assembling atypical tubulin structures . However2SO4 treatments.Using TEM, we also analyzed the state of the tubulin cytoskeleton in the root cells of the control (WT) and transgenic tomato plants under NaCl and Na2SO4  transgenic plants were more tolerant to methyl viologen mediated oxidative stress and withstood salinity stress of 150 mM NaCl for a period of eight days while the untransformed control plants wilted at the end of the stress treatment in hydroponics [Tamarix androssowii, suggesting an important role of increased SOD activity in salt tolerance [A. thaliana transgenics overexpressing cytosolic CuZn-superoxide dismutase (PaSOD) from Potentilla atrosanguinea, cytosolic ascorbate peroxidase (PaSOD) from Rheum australe and dual transgenics overexpressing both the genes were developed and analyzed under salt stress. In comparison to wild-type (WT) or single transgenics, the performance of dual transgenics under salt stress was better with higher biomass accumulation and cellulose content at 100 mM salt stress [A tolerance to stressful conditions is known to correlate with the activity of enzymes involved in ROS detoxification . The approponics . In anotolerance . Additiot stress . HoweverThe cap is a sensitive model that responds quickly to the action of most edaphic factors. It provides an orientation of root growth, location of roots in space and a number of other functions. These functions are provided due to a complex mechanism associated with the transport of sugars from the aboveground part, the redistribution of starch in the tissues and root zones, and their hormonal regulation. This is reflected in the structural organization of the meristematic zone, columella, and lateral cells of the root cap .In the present study, the negative effect of salts led to a marked inhibition of both the columella cell formation and the injury of the cell shape and vacuolization . This efThe vacuolar compartment contributes to the adaptive mechanisms of structural cell transformations and tissues during salinity. The most important responses of the vacuolar system to harmful influences can be: disruption of fusion, when the resulting vacuoles remain in the places of their formation; displacement of the vacuole relative to the characteristic central location; shape change from rounded to irregular. All these external manifestations can be the result of various violations of osmotic homeostasis, as well as a violation of the cytoplasm ability to move due to a decrease in fluidity or the appearance of obstacles in the form of the cytoskeleton abnormal transformations. In this work, the activation of the vacuolization processes in meristem and cap cells during ectopic overexpression of Fe-dependent superoxide dismutase was revealed, which indicates an important role of ROS in the regulation of the vacuole initiation processes and the regulation of their fusion and growth. Changes in the cell vacuolization of the root tip and meristem were detected under salts both in control tomato plants and in FeSOD-transgenic line 19 . It was 2SO4 result in further growth inhibition and various damage to macromolecules during the formation of ROS [2O2, caused by the functioning of Fe-dependent superoxide dismutase, led to an increase in the adaptive cell capabilities of transgenic tomato plants and the preservation of their growth and development despite inhibition by toxic ions.An increase in the ROS pool was the expected effect of salt exposure . We expen of ROS . It can 2SO4 on the system of cortical microtubules in the root cells of control (WT) and FeSOD-transgenic tomato plants. Initially, we analyzed the root cells cytoskeleton of non-transgenic and transgenic plants grown without salt exposure. It was found that in this case, the microtubule system in the interphase tomato root cells was different. In cells of WT, a cortical network of microtubules was visible, in which the bundles are located parallel to each other, and perpendicular to the cell growth axis. The cells themselves had a typical shape characteristic of the cells in these layers. A different situation was found in the root cells of the transgenic tomato line 19. Here, the organization of the microtubule system was disrupted. Thus, the study revealed short, rare, chaotically oriented microtubules. In line 19, no ordered cortical network was found in comparison with WT. Another difference is the atypical cell morphology s, in which an increased degree of vacuolization is shown, which, apparently, could become one of the reasons for the displacement and deformation of the nucleus. Further, the network of cortical microtubules in root cells of WT and transgenic tomato plants was compared under NaCl stress. Substantial differences between the elucidated variants were noticed. Thus, the parallel organization of cortical bundles in WT root cells, characteristic of conditions without sodium chloride addition, showed signs of disorganization. Network chaotization, the formation of microtubule converging centers, and the fragmentation, shortening and thickening of the bundles were found. On the contrary, in transgenic tomato line 19, the structural organization of the microtubule network in root cells was more ordered upon the addition of NaCl than under non-saline conditions. This was manifested in the observation that there were more microtubules in the cytoplasm of root cells than in non-saline conditions, and they formed an ordered or chaotic network in the cortical cytoplasm. Along with this, cells with rare, short and thick bundles were sometimes revealed. Similar changes in plant root cells were observed when plants had been growing in the presence of Na2SO4. In the WT, the microtubule network chaotization of the formation of convergence foci and the change in the microtubule bundle orientations relative to the growth axis are clearly manifested (Cortical microtubules play a vital role in plant cell growth , and arenifested . The celFeSOD gene in transgenic tomato plants leads to an increase in the tolerance to stress factors, the formation of atypical tubulin polymers under stress conditions accompanied by an increase in the ROS level is a manifestation of such a protective reaction [2O2 levels, which significantly enhanced oxidative stress tolerance by elevating the antioxidant status of the plant cells and tissues [Some researchers have suggested that when ROS homeostasis in cells changes, the tubulin cytoskeleton passes into another structural state by assembling atypical tubulin structures . The assreaction . It is areaction . We belireaction . This wa tissues . The resA variation in the oxidative status of a cell due to heterologous expression of Fe-dependent superoxide dismutase leads to an alteration in the structural and functional organization of the root tip, a change in the ROS localization in the cap, cortex and stele, and a disruption in the dynamic transformations of the microtubule cytoskeleton, contributing to a change in cell vacuolization, primarily of the columella and cortex. The introduction of the heterogenous superoxide dismutase gene into the tomato genome made it possible to significantly mitigate the harmful effects of salt stress on intracellular structures caused by the application of sodium chloride and sulfate.The determination of the functional cell state using intravital markers would be effectively used in future estimations for the rapid assessment of the oxidative status of plant root cells grown under various stress factors.


This study aimed to evaluate the effectiveness of using ultrashort implants in the rehabilitation of jaws of fragile patients. The aim of the study was to retrospectively evaluate the survival rate of full-arch prosthetic rehabilitation on ultrashort implants, length 4 mm, 4 mm in diameter in the premolar and canine area and 4.5 mm in diameter in the molar area, with the insertion torque of 60 Nw and immediate loading. Nineteen patients were evaluated for 3 years clinically and radiographically. The significant majority of the patients at the 3 year follow-up (T4) presented a stable and functional implant-supported prothesis, and the survival rate of the implants was 85%, with a loss of 16 implants on 114 implants. The combination of the innovative implant surfaces and the correct project of the prostheses, with the related implant connection, determined a different timing in the therapy, allowing to obtain an immediate loading, which is currently demanded by patients. This and recent reports on short and ultrashort implant usage in atrophic jaws offer a good solution in critical cases. In conclusion, within the limits of the study, the full-arch rehabilitation with immediate loading on ultrashort implants showed good results with few postoperative complications and related low biological cost. The rehabilitation of edentulism in atrophic jaws represents a difficult situation to face, especially in fragile patients . Indeed,The implant-supported prosthetic solutions require a bone quantity able to host the implant fixture and, in cases of atrophic jaws, ridge augmentation is required to place a fixture of “normal” length (≤10 mm) . These kThe definition of a short implant is still a topic of debate; some researchers define “short implants” as fixtures having a length ranging between 7 and 10 mm, whereas others define them as fixtures presenting an intrabony length of 8 mm .Indeed, some researchers consider 10 mm or less as short, while others propose <8, <7, or 6 mm as truly short ,6. NeverDue to the biological and economic advantages in using this type of fixture to prosthetically rehabilitate an atrophic jaw, several studies reported at various follow-up points the survival rates of fixed prostheses implant supported, showing their efficacies ,11,12.Indeed, the consensus report of the Group 1 ITI  in 2018 evaluated the survival rates of short implants as similar to longer implants, with a lower rate of post-intervention complications if compared to the longer implants placed together with the procedure of bone grafting .The success of the rehabilitation of an edentulism relies on the primary stability of the implant and on the correct project of the prosthesis, which should follow the masticatory dynamic of the patient, especially in full-arch rehabilitation .In the Group 1 ITI consensus report, it is indeed stated the survival rate of short implants is influenced by the functionality.Therefore, the construction of overdentures should be done with respect to the physiological state of the patient, known as the neutral zone, so that harmful masticatory forces do not affect the implants .The combination of innovative implant surfaces and the correct project of the prostheses, with the related implant connection, determined a different timing in the therapy, allowing to obtain an immediate loading ,17,18.Immediate loading indeed relies on many factors, such as the number of implants and the biological bone response (mostly the primary stability) ,20.In case of short implants, the improvement of the surfaces allows an optimal primary stability and, as a consequence, the possibility of immediate loading.The aim of the study was to retrospectively evaluate at different timings the survival rate of full-arch prosthetic rehabilitation on ultrashort implants (length 4 mm), with immediate loading.Between 2015 and 1027, approximately 150 patients that needed a total implant-supported inferior rehabilitation were examined at the Department of Odontostomatology of the University of L’Aquila. In order to achieve a successful prosthetic rehabilitation, all patients were studied through our new clinical protocol, which included a first gnathological evaluation through RC-TMD (Research Criteria- Temporomandibular Disorders) to evaluate the stomatognathic functional status [The following exclusion criteria were applied for the selection of the study group: patients smoking more than 12 cigarettes per day; patients with high risk factors; patients on bisphosphonate therapy; patients who underwent radiotherapy of the head and neck region in the previous 12 months; patients with temporomandibular and/or parafunctional dysfunctions; pregnancy; poor oral hygiene or inability to undergo the follow-up protocol. The following inclusion criteria were applied for the selection of the study group: patients over the age of 18; lower total edentulous patients or patients made edentulous due to the presence of severely compromised teeth; mandibular atrophy with residual crest not less than 5 mm from the roof of the mandibular canal; authorization by the patient to participate in the study.Of the 150 patients, 40 were excluded because they were severe smokers, 12 were on bisphosphonate therapy, 41 had high risk factors, five had temporomandibular osteoarthritis, 25 were unable to follow the protocol, and eight had poor oral hygiene. The resulting sample consisted of 19 subjects, of which 11 were men aged between 62 and 77 with an average age of 69.5 and eight were women aged between 61 and 71 with an average age of 66.According to the Italian legal system no. 127 of 1996, these patients are counted as fragile subjects, not only due to their age, but also due to their economic status and local biological conditions. All selected patients were completely edentulous or to be rendered edentulous as the residual elements could not be used as a source of anchorage.The sample was subjected to preventive anamnestic tests and then underwent imaging tests for therapeutic planning.The Ethics Committee approved the study (n. 55/2018.19), and all patients signed an informed consent form.The sample underwent implant surgery with the use of ultrashort implants  Twinkon4, TEKKA, Global D. This type of implant is a grade 5 titanium alloy (TiAI6V4), sandblasted and double-etched, with a surface roughness of 1–2 μm.A temporary prosthesis with immediate loading was applied to all patients, since the characteristics of the implant design and of the transmucosal type allowed no solution other than to solder the implants, as already experimented in other implant prosthetic protocols.The implant surgery involved the use of the ultrashort implants (4 mm long) Twinkon4, TEKKA, Global D. This type of implant is a grade 5 titanium alloy (TiAI6V4), sandblasted and double-etched, with a surface roughness of 1–2 μm.All the considered patients were fitted with a temporary prosthesis with immediate loading.The surgical protocol involved oral administration of antibiotic therapy with 2 g of amoxicillin 1 h before and then 1 g every 12 h for 5 days.Before starting the surgery, the perioral surface was disinfected with povidone iodine (10% Betadine), while the patients were intraorally rinsed with a 0.2% chlorhexidine solution for 60 s. The loco-regional anesthesia was performed with 4% articaine with epinephrine 1:100,000 .The protocol included the use of a positional guide for the implant placement.The positional guide was applied, and a punch was made on the crestal mucosa to find the positioning of the implant; then, a full thickness crestal incision was made to skeletonize the underlying bone .The Tekka protocol was used for the positioning of the ultrashort implants . This protocol requires the use of drill bits with increasing diameter up to the diameter necessary for the insertion of the corresponding implant. A total of 38 TwinKon 4 implants, with a 4.5 mm diameter, were placed in the area 3.6 and 4.6. A total of 76 TwinKon 4 implants, with a 4 mm diameter, were placed in the area of the premolar and canine. The insertion torque was 60 N.Once the mucosa was sutured with detached or X-shaped stitches, the temporary prosthesis was fixed on the temporary abutment, taking care to make the peri-implant area easy to clean using routine oral hygiene procedures .® TENS Unit device of Myotronics-Noromed, Inc., Tukwila, WA, USA) with electrodes , whereas resin was used for the detections   of the dental arches; then, an articulation base was built for the detection of the neutral space and for the vertical dimension. This method used TENS  stimulation (J5 Myomonitoryoprint) .Subsequently, both a conventional prosthesis and a baryta resin duplicate were made to perform the cone beam.In order to find the implant position, the DICOM  images were processed with the acquisition program (3 shape Implant Studio) to create a positional template for the surgical phase.The implant position was guided by a functional gnathological evaluation and by a series of prosthetic reference factors such as the distribution of the occlusal load and the neutral space .Seven days after surgery, a clinical examination of the patient was performed, in which the healing status of the mucosa and the implant stability were analyzed and the sutures were removed. After 4 months, a cone beam was performed to assess whether the bone healing status had no problems b, beforep-value <0.05.The primary outcome was the number of patients who, at the 3 year follow-up, had a stable prosthesis supported by at least four implants, evaluated using chi-square test. The secondary outcome was the implant survival at T1, T2, and T3, statistically evaluated using the Fisher exact test, and the endpoint was the survival rate of the implants at T4. Any statistically differences were considered significant at a Nineteen patients were included in the retrospective analysis, 11 males and eight females, with an age ranging from 64 to 77. Implants were mostly lost 1 week after loading and at the fourth month follow-up.p < 0.05).Eighteen patients at T4 presented a stable prothesis supported by ≥4 implants. As shown in The Fisher exact test applied to determine the implant loss occurrence at the considered follow-up periods  showed a statistically significant difference .At T4, the survival rate of the implants was 85%, with a loss of 16 implants from a total of 114 implants.The retrospective follow-up of patients who underwent full-arch rehabilitation with ultrashort implants showed how the critical points of rehabilitation were the first week and the 4 months after implant placement and the related prosthetic loading, as observed in the literature [Overall, the unsuccess of the rehabilitation was not frequent, and basically only one patient could not rely on this type of prosthetic rehabilitation.If the surgical intervention on jawbones is considered as a minor type on surgery and with a very low risk, the diagnosis and planning stages are fundamental for rehabilitation, which can be comfortable and satisfying for the patients .The oral cavity, with its sensitivity and peculiar functionality due not only to its occlusion and masticatory function but also to its phonatory, respiratory, and tasting function, requires a careful rehabilitation plan .Currently, the rehabilitation of small edentulism requires an established plan, facilitated by the presence of other dental elements. Edentulism cases requiring a complete denture rehabilitation are challenging for both anatomical and functional reasons . Indeed,The loss of the vertical dimension modifies the functionality of the masticatory organ, and spotting the neutral zone might be difficult .Several surgical techniques are available to improve the volumetric bone availability. Vertical ridge augmentation, large sinus lift, xenograft interventions, and placing of pterygoid implants or zygomatic implants are some of the most famous and new techniques proposed in the literature . HoweverThe improvement of implant surfaces and the establishment of defined surgical protocols allowed short implants to be a reliable alternative to rehabilitate small edentulism in atrophic jaws; however, the rehabilitation of full edentulism using full-arch prostheses has also been reported with a certain degree of success.Overall, the primary outcome showed the success of the ultrashort implant-supported prosthetic protocol. However, the rate of implant loss was slightly higher, if compared with the survival rate reported by the Group 1 ITI Consensus Report, which reported a survival rate ranging from 86.7% to 100% . HoweverThe available studies in the literature reported the survival rate of short and ultrashort implants with immediate or delayed loading supporting single crowns ,25,26,27On the other hand, few case reports are available in the literature reporting full-arch prothesis supported by ultrashort implants and placed with immediate loading ,19,28.Indeed, Falisi et al. reported a full-arch rehabilitation on ultrashort implants with no postoperative complication and success of the prosthesis integration, in functional and aesthetic terms. In this case, the prosthesis was planned according the neutral zone of the patient .Pistilli et al. also reported the case of a rehabilitation of a severe atrophic mandible on implants no longer than 4 mm, highlighting how this therapeutical choice reduced timings, costs, and postoperative complications. In this case, the occlusal loading was the most balanced .However, the data of a previous study showed how immediate loading can affect the survival rate of implants but not the final prothesis success, showing how the correct distribution of the occlusal forces in the period after implant insertion can positively influence the final outcome .Indeed, the healing period after the surgical stage is the most crucial one, since the bone tissue is submitted to a remodeling process balanced between the resorption and production of the mineralized tissue .The theme of immediate loading on short implants is still under investigation among scientists and clinicians. Indeed, Weerapong et al., on the basis of the results of their randomized clinical trial, stated that immediate loading on short implants gives survival rates comparable to immediate loading on longer implants, together with the use of new technologies and CAD/CAM (Computer Aided Design/Computer Aided Manufacturing) replanning of the prosthetic device .Within the limits of the current study, regarding the sample size and the observational nature of the study, the full-arch rehabilitation with immediate loading on ultrashort implants showed good results with few postoperative complications and related low biological cost.Future prospective studies and randomized clinical trials with a larger sample size are needed to evaluate the survival rate of full-arch rehabilitation on short and ultrashort implants with appropriate occlusal loading.Results from our study suggest the adequate clinical performance of short implants after 3 years of immediate loading. Thus, 4 mm ultrashort implants with a diameter of 4 and 4.5 mm could represent a good alternative to rehabilitate edentulous atrophic jaws or jaws with residual elements that cannot be used as a source of anchorage. The study was approved by the Internal Review Board of University of L’Aquila, n. 55/2018.19.


Furthermore, ECM processing of 42CrMo4 in sodium nitrate solution was strongly determined by a stationary process with two parallel running steps: 1. Transpassive Fe3−xO4 mixed oxide formation/repassivation; as well as 2. dissolution of the transpassive oxide at the metal surface.The efficiency of material removal by electrochemical machining (ECM) and rim zone modifications is highly dependent on material composition, the chemical surface condition at the break through potential, the electrolyte, the machining parameters and the resulting current densities and local current density distribution at the surfaces. The ECM process is mechanistically determined by transpassive anodic metal dissolution and layer formation at high voltages and specific electrolytic compositions. The mechanisms of transpassive anodic metal dissolution and oxide formation are not fully understood yet for steels such as 42CrMo4. Therefore, martensitic 42CrMo4 was subjected to ECM in sodium nitrate solution with two different current densities and compared to the native oxide of ground 42CrMo4. The material removal rate as well as anodic dissolution and transpassive oxide formation were investigated by mass spectroscopic analysis (ICP-MS) and (angle-resolved) X-ray photoelectron spectroscopy ((AR)XPS) after ECM. The results revealed the formation of a Fe Electrochemical machining (ECM) of metals is increasingly gaining in importance in the field of subtractive manufacturing technology. In recent years, intensive research has opened up new application areas for the ECM process, for example, the production of turbine blades ,2, the m3O4 and γ-Fe2O3 was assumed. Davenport et al. [2O3 was mainly present at the interface between the oxide and the electrolyte. With increasing thickness of the oxide, the proportion of Fe3O4 in the oxide increases continuously towards the oxide/metal interface. However, the question of whether the oxide was crystalline or amorphous was conclusively clarified in this study. Ryan et al. [2O3 at the oxide/electrolyte interface by using atomically resolved scanning tunneling microscopy (STM). In addition, the change of the oxidation state of the passive layer was also reported for highly alkaline electrolytes. XPS investigations by Haupt et al. [It is well known that at the break through potential the transformation of the passive layer as well as oxygen evolution leads to a significant increase of the transpassive current densities. Numerous investigations have been carried out on the chemical composition and structure of the passive layer formed on iron between the passivation and breakthrough potential in borate buffer solution (pH 8.4), which is assumed to be comparable in terms of pH to the sodium nitrate solution used in this work. Based on the results by Nagayama et al. , the past et al.  were ablt et al. , the pasn et al.  confirmet et al.  revealed3O4 spinel. The group of Rokosz, Hryniewicz et al. [2 in a mixture of phosphoric and sulfuric acid using XPS. It was proven that the thickness and the chemical composition of the oxide layer formed during the process depends on the current density, the material and the electrolyte. However, it was reported that the oxide layer consisted mainly of iron oxide, either in the oxidation state of Fe (II) or Fe (III), and was enriched by additional alloying elements, such as chromium or molybdenum, for acidic electrolytes at low transpassive current densities. Considering the oxide formation for iron at higher transpassive current densities and a sodium nitrate electrolyte, a layer consisting mainly of Fe2O3 with partially bivalent iron Fe (II) was observed as early as 1984 by Datta et al. [2 compared to a thickness of about 2–4.5 nm for the native oxide. In addition, it was observed that the thickness of the oxide layer strongly depended on the current density. An oxide layer with a maximum thickness of about 20 nm was observed at low current densities up to 8 A/cm2 and oxygen evolution was a predominant reaction. However, with increasing current densities above 8 A/cm2, the thickness of the oxide layer decreased again.Considering the formation and transformation of surface layers during ECM processing of iron at transpassive current densities, Foley et al.  reportedz et al. ,23,24,25a et al.  using at2O3 at low transpassive current densities. These results were obtained by analyzing the oxidation state of iron within the electrolyte by UV-VIS. At current densities above about 10 A/cm2, however, a mixture of Fe2O3 and Fe3O4 seemed to be present. Furthermore, the proportion of Fe3O4 increased with increasing current densities. Wang et al. confirmed these results by XPS studies on stainless steel that was ECM processed in sodium nitrate solution [2 by analyzing the reaction products in the process electrolyte by UV-VIS. It was proposed that both oxides, i.e., Fe2O3 and Fe3O4, were formed at all investigated current densities.Additional microflow cell investigations on the oxide formation of iron in sodium nitrate solution by Lohrengel et al. ,28,29,30solution . In contsolution  did not The composition, structure and thickness of the oxide layer formed during the ECM process influence the efficiency of material removal, the achievable manufacturing accuracy and surface quality. According to Hoare , well-prBesides the controversial observations on the formation of oxide layers during ECM processing of iron in sodium nitrate solution at high transpassive current densities, the formation of an additional viscous layer of hydrated iron nitrate has been reported by Lohrengel et al. ,28,29,30In summary, the oxide layers that form in the transpassive area at low  and high  anodic current densities have come increasingly into the spotlight for predicting the electrochemical metal dissolution and material removal in recent years. However, determining the overall and local stoichiometric composition, the chemical distribution of additional alloying elements and structure of transpassive layers on ferrous materials is a challenge, and discussions have remained controversial for a long time. Therefore, the aim of this work is to investigate how electrochemical machining affects the composition, specifically the chemical distribution of the alloying elements, and structure, e.g., given by the oxidation state, of the oxide layer on a martensitic 42CrMo4 steel. Furthermore, the influence of the current density on the mechanism of oxide layer formation will be studied.The formation of oxides during ECM was investigated for martensitic 42CrMo4 steel (AISI4140) surfaces. The main alloying elements were chromium, manganese and molybdenum. The detailed chemical composition of the steel is shown in The 42CrMo4 steel was austenitized for 2 h at 850 °C and quenched in oil at 60 °C. Afterwards, the material was tempered at 400 °C for 4 h and cooled down to room temperature in air. The 42CrMo4 in quenched and tempered condition had a hardness of 470 HV0.2, a Young’s modulus of 202,800 MPa, a yield strength of 1430 MPa and a tensile strength of 1570 MPa. Finally, the material was cut into square plates with an edge length of 10 mm and a height of 2 mm and ground with 2000 SiC abrasive paper to obtain comparable initial surface conditions.2.The martensitic 42CrMo4 was electrochemically machined using an EMAG PTS 1500 ECM device  with an applied external DC voltage of 19 V. A sodium nitrate electrolyte with a conductivity of 135 mS/cm and a pH value of about 8 was used as a process electrolyte at a temperature of 36 °C. The flow rate of the electrolyte was 4.4 L/min. 42CrMo4 was used as the anode and a movable stainless steel performed as the cathode during the ECM process. Both anode and cathode exhibited a surface area of 1 cmTwo different ECM processes were performed on 42CrMo4: ECM-A and ECM-B. The two processes mainly differ in the size of the working gap between anode and cathode. Furthermore, the feed rate of the cathode was varied, as shown in The process electrolyte was analyzed in terms of its chemical composition before and after ECM using mass spectroscopy with inductively coupled plasma  GmbH, Rodgau, Germany). The advantage of this analysis is, on the one hand, to obtain information about the amount of material removed during ECM, and on the other hand, it makes it possible to draw conclusions on the material removal mechanism. Electrolyte samples were taken after reaching stationary ECM process conditions, which means for ECM-A after a period of 80 s and for ECM-B after a period of 10 s. Before ICP-MS measurements, the samples were diluted with 2% nitric acid in a ratio of 1 to 50.X-ray photoelectron spectroscopy (XPS) analyses of the ground as well as ECM surfaces were carried out in a Kratos Axis Supra instrument  using a monochromatic Al Kα X-ray source (hν = 1486.6 eV). High resolution spectra of the O 1s, C 1s, Fe 2p, Cr 2p, Mo 3d, and N 1s regions were obtained using a pass energy of 20 eV and a step size of 0.1 eV. Angle-resolved measurements were performed with take-off angles of 0°, 30° and 45° with respect to the surface normal. Peak deconvolution and quantification were performed using the ESCApe software provided by Kratos Analytical Ltd. . All spectra were charge corrected by assigning the adventitious C-C/C-H contamination component in the C 1s peak to 284.8 eV. Shirley type backgrounds were applied, and peak fitting was performed using Gauss-Lorentz (30/70) type line shapes with an exception for metallic Fe and Cr components, which required asymmetric line shapes.Material removal of 42CrMo4 in sodium nitrate solution by ECM is determined by metal dissolution, and the formation of an oxide layer and a polishing film at the surface. Further, it is well known that the current density significantly influences the material removal rate during ECM, and therefore the anodic dissolution and oxide layer formation, at high transpassive potentials. However, the influence of the current density on the mechanism of metal dissolution and the oxide formation at the surface is still controversial discussed ,40.2 and for the ECM-B process 34.0 ± 1.2 A/cm2.Focusing first on the influence of the current density on the electrochemical material removal, the current densities for both the ECM-A and ECM-B processes were determined. The influence of the current density on the material removal and the efficiency of the ECM process was determined by three different methods: First, a theoretical material removal was calculated using Faraday’s law and considering the measured current densities. Second, the material removal was determined by measuring the height difference of the 42CrMo4 samples before and after ECM; and third, the material removal was calculated by analyzing the mass of the reaction products in the electrolyte with process time using ICP-MS. The results of the differently calculated material removal rates are compared and shown in The material removal rate of ECM-B is, independent of the measuring and calculation method, about twice as high as that of ECM-A. In addition, it is noticeable that the real removal rate is lower when calculating via height difference than when calculating via ICP-MS. This is due to the fact that in the height measurement only the highest point of the sample is measured. However, since the removal is not uniform over the entire surface, the real material removal is underestimated when calculating via height measurement. The calculation via ICP-MS measurement of the removal products in the electrolyte is therefore better suited to describe the real material removal rate. A further advantage is the increased accuracy of the ICP-MS measurements compared to height measurement. For all further calculations in this work, the removal rates of the ICP-MS measurement are used.theoreticalmr) and the real measured material removal , as shown in Equation (1).The efficiency of the ECM process can be determined by comparing the real material removal with the theoretical material removal (Faraday’s law). The charge yield η is a measure for the efficiency of material removal. It is calculated from the theoretical (The charge yield of the ECM-B process (70%) is higher than that of the ECM-A process (60%). This means that the ECM-A process has relatively higher losses. Therefore, less energy is available for metal dissolution.For a detailed understanding of the anodic metal dissolution mechanisms dependent on the current densities, the composition of the process electrolyte was determined for iron, chromium, manganese and molybdenum by ICP-MS. The concentration of the dissolved individual elements chromium, manganese and molybdenum in the ECM electrolyte were placed in a ratio against the dissolved iron to compare both ECM processes . If thesIn addition to the analysis of the material removal rate and the element specific anodic dissolution, the focus of this work is the investigation of the formation, composition and structure of the oxidic rim zone of the martensitic 42CrMo4. The oxide layers are in the range of about <50 nm, and are therefore not visible on SEM cross sections. Even higher-resolution investigations by TEM are not sufficient for a full characterization of the oxide layer on 42CrMo4 steel . TherefoIt is well known that oxygen and carbon form contamination products at surfaces that are not related to the formation of surface layers during ECM. Therefore, the absolute contents of all measured elements provide only limited information about the actual composition of the rim zones. However, considering the ratio of iron to chromium and of iron to molybdenum allows a more precise evaluation of the XPS results. 3−xO4 is assumed to be simplified for the oxide layer. X is the variable iron deficiency. According to Biesinger et al. [3/2 region, which is shown as an example for the ECM-B surface in In addition to the content of the different elements, the XPS measurements also provide information about the stoichiometric composition and structure of the formed oxides at the surfaces. Iron is by far the most important metallic component in the material and is therefore a particular focus of attention. According to common models from previous research, the structure Fer et al. , the meaThe evaluation of the XPS results of the ground 42CrMo4 surface indicates that the examined area of the rim zone exhibits a metallic content of about 20% . Approxi3−xO4 for both investigated surfaces. However, the results indicate that the average oxidation number of iron increases more significant from the metal/oxide interface to the oxide/air interface for the native oxide in comparison to the oxide formed during ECM-B processing.Angle-resolved XPS measurements (ARXPS) were performed on one hand to investigate the local differences in the oxidation states of iron in the depth profile, and on the other to evaluate the thickness of the oxides for ground and ECM-B 42CrMo4 . It was 3/2 region, a significant metallic content was detected in the ground surfaces. This was significantly lower for the ECM surfaces and was related to the fluctuation of the measurements, and was therefore neglected. It is also noticeable that the proportion of hexavalent chromium in the oxide on the surface increases with increasing current density compared to the predominant trivalent chromium.Chromium was analyzed in addition to iron using XPS. The XPS fitting parameters for chromium were taken from Biesinger et al. . The resIn addition, molybdenum was investigated by XPS. However, due to the small amount of molybdenum present in the native and the oxide formed after ECM only qualitatively conclusions can be drawn. An increase in the average oxidation number with increasing current density from the ground samples via ECM-A to ECM-B are determined and it is assumed that this is related to the transition from tetravalent to hexavalent molybdenum. Fitting parameters for molybdenum are taken from Baltrusaitis et al. .Considering the current research and the controversy when discussing the formation of a nitrate-based polishing film during ECM in sodium nitrate solutions, XPS measurements were also performed to obtain detailed results on the occurrence of such a film. The XPS measurements  qualitatIt is widely known that the oxide formation during transpassive material removal of martensitic 42CrMo4 steel by electrochemical machining significantly influences the material removal rate. However, discussed surrounding the formation, stoichiometric composition and structure of the formed oxides remain controversial. The aim of this work is to investigate how electrochemical machining affects the composition, specifically the alloying element distribution, and structure, given by the oxidation state, of the oxide layer on a martensitic 42CrMo4 steel. In addition, the influence of the current density on the mechanism of oxide layer formation will be discussed.The XPS and ARXPS investigations provided information on both the chemical composition and the structure of the oxides of the ground and ECM 42CrMo4 rim zones. Considering first the chemical composition, regarding the distribution of the alloying elements within the oxides, the results revealed  that bot2 or 34.0 A/m2 was evaluated by the iron/alloying element ratio, considering chromium and molybdenum. No influence of the current density was observed within the context of this work. However, this does not explicitly mean that the local stoichiometric chemical composition of the oxide layer does not change with increasing current density. For example, the oxygen content in the layers could not be measured quantitatively because of impurities at the surface. Therefore, it is possible that the proportion of the elements iron, chromium and molybdenum in the oxide layer decreases compared to oxygen. Such a change would be indicated by a change in the oxidation numbers of the elements.The influence of the current density of the ECM process on the alloying element distribution within the oxides formed at 20.6 A/cm3O4-like structure to a Fe2O3-like structure, considering a Fe3−xO4 mixed oxide. Evaluating the XPS measurements, it is important to consider that the exact determination of the proportions of the oxidation states of iron and chromium in the oxide layer using XPS is also subject to error. The individual peaks of the oxidation states overlap strongly, as shown exemplarily for iron in As a result, the XPS results are discussed in the following according to structural changes indicated by the change of the oxidation state. As demonstrated in 3O4 content in the transpassive oxide layer was assumed with increasing current density and a decrease of the Fe2O3 content accordingly. In contrast, Münninghoff [Changes in the oxidation numbers of metals in electrochemically formed oxide layers have already been described in previous investigations. Keller  was ableninghoff  could no3O4 on the surface of iron increased with increasing current densities.An explanation for the contradictory results may relate to the fundamentally different experimental setups. Lohrengel et al. ,28,29,302 (ECM-B), however, nitrates and nitrides were detected. The nitrates may have been drying residues of the electrolyte used. However, it is more likely that the observed nitrates and nitrides were formed during the reaction of the electrolyte with the metallic material at high current densities. Datta et al. [3−). It was assumed that the nitrogen penetrated the oxide layer at defects.The XPS measurements of 42CrMo4 after ECM processing revealed, in addition to the metallic elements iron, chromium and molybdenum, nitrogen, too, and indicated the existence of a polishing film of supersaturated iron nitrate also for 42CrMo4. In the case of the ground surfaces and the ECM-A surfaces, the observed nitrogen was most likely due to contamination. On the surfaces from the ECM process with a high current density of 34.0 A/cma et al.  were alsa et al.  the nitrThe observed change in the oxidation mechanism for 42CrMo4 in comparison to iron reported by Lohrengel et al. ,28,29,303−xO4 mixed oxide also has to be considered in order to explain the mechanistic change of oxidation for 42CrMo4 in comparison to iron.Furthermore, the impact of the additional alloying elements, which revealed various oxidation states, such as Cr (III), Cr (VI), Mo (IV) and Mo (VI), must also be considered regarding the change of the oxidation mechanism dependent on the different current densities. Similar to the results for iron, the studies of the oxidation states of the additional alloying elements revealed an increase in the oxidation state with increasing current density due to a higher driving force for oxidation at higher current densities. In addition, the substitution of the different additional alloying elements led to a change in the number of vacancies, as well as to a local change of the stoichiometry. This was driven by the thermodynamics of oxide formation as well as by the oxidation state of the specific species at high transpassive potentials and current densities. Therefore, in addition to the influence of the water-soluble polishing film, the impact of the substitution of the additional elements within the FeIn addition to the already-presented XPS analyses on the structure of the oxide layer, the process electrolyte was examined by ICP-MS. It was demonstrated that the ratios of iron to chromium and iron to molybdenum in the electrolyte after the ECM processes were similar to the ratios of these elements determined in the oxide after ECM. In both cases, a significant enrichment of the elements chromium and molybdenum compared to iron was found in the electrolyte. This indicates that the transpassive metal dissolution in ECM is a stationary process with two parallel running steps. These steps are determined by oxide formation at the metal surface and dissolution of the transpassive oxide into its components.2, variables influencing the anodic dissolution and oxide formation of the ECM process could be identified. The following conclusions are drawn:2 is, independent of the measuring and calculation method, about twice as high as that of ECM-A, at 20.6 A/cm2. The efficiency calculation revealed relatively higher losses for the ECM-A process. Therefore, less energy is available for metal dissolution at low current densities.The material removal rate of ECM-B at 34.0 A/cmThe oxide layers formed during ECM are more strongly enriched with chromium and molybdenum than the native oxide layer on ground 42CrMo4.With increasing current density of the ECM process, the average oxidation numbers of iron, chromium and molybdenum increase within the oxide layer due to the higher driving force for oxidation.3−xO4 mixed oxide is concluded to have increasing oxidation state from the inner interface metal/oxide towards the outer interface oxide/electrolyte, in contradiction to previously reported results for iron. The change of the oxidation is related on one hand to the changed transport mechanism related to the formation of a water-soluble polishing film of iron nitrate and on the other hand to the substitution of the additional alloying elements within the Fe3−xO4 mixed oxide depended on the current densities.The formation of Fe3−xO4 mixed oxide measured by XPS is almost similar to the iron/alloying element ratio detected as a reaction product in the electrolyte by ICP-MS. It is concluded that the material removal rate and the efficiency of ECM processing of 42CrMo4 in sodium nitrate solution is strongly determined by a stationary process with two parallel running steps: 1. Transpassive Fe3−xO4 mixed oxide formation/repassivation; as well as 2. dissolution of the transpassive oxide at the metal surface.The iron/alloying element ratio, and therefore the element distribution, within the FeIn this study, the influence of electrochemical machining on the composition, specifically the chemical distribution of the alloying elements, and structure, e.g., given by the oxidation state, of the transpassive oxide layer on a martensitic 42CrMo4 steel was investigated. A further focus was on investigating the influence of the current density on the mechanism of oxide layer formation at a high transpassive potential. The mechanism of material removal was analyzed with respect to anodic dissolution and oxide formation in sodium nitrate solution used during ECM processing. By linking the electrolyte composition measured by ICP-MS after ECM and the chemical distribution as well as the oxidation states of the single alloying elements within the native oxide, as well as within the oxides measured by (AR)XPS and formed during ECM at 20.6 and 34.0 A/cmFurther work on the influence of microstructure on ECM processing of 42CrMo4 is underway to investigate, e.g., the differences on transpassive oxide formation for ferritic-pearlitic compared to martensitic microstructure. In addition, it is of interest to study the influence of the transpassively formed oxide layers on the functionality of the machined component, for example the oxidation resistance.