Implant rehabilitation of the edentulous jaws: Does tilting of posterior implants at an angle greater than 45° affect bone resorption and implant success?: A retrospective study.
PURPOSE
This study aimed to (1) investigate the success of posterior implants tilted >45° when 4 immediately loaded implants were used to support full-arch prostheses, eliminating any distal cantilever and (2) examine the effect on marginal bone loss (MBL) of different combinations of anterior multi-unit abutment (MUA) angles and posterior implant tilting angles.


MATERIALS AND METHODS
Records of patients rehabilitated according to the Columbus Bridge Protocol were analyzed. Peri-implant bone levels (PBLs) and MBL were measured for each implant. The influence of posterior implant tilting angle on PBL, MBL, and implant and prosthetic success rate was investigated. The impact on the same endpoints of different anterior MUA angles, and different combinations of anterior MUA and tilted posterior implant angles was also examined.


RESULTS
Records of 41 patients were analyzed, for a total of 46 complete rehabilitations, and 142 implants (52 anterior, 63 posterior tilted ≤45° [group 1], and 27 posterior tilted >45° [group 2]). No implants were lost during the follow-up (25.9 months), and no prosthetic complications were reported. Success rate for posterior implants was 100% in group 1 and 96.3% in group 2. Mean MBL differed significantly between the 2 groups (0.45 mm in group 1, 0.66 in group 2 [P = .04]), but not when the analysis was limited to implants in the same jaw. Implant tilting angle did not correlate with MBL and the MUA angle had no effect on bone resorption around posterior implants, neither in the sample as a whole nor in individual patients.


CONCLUSIONS
Posterior implants tilted >45° to eliminate distal cantilever may be as safe as those tilted less in severely atrophic jaws rehabilitated with immediately loaded, full-arch prostheses supported on 4 implants. Further prospective studies on larger samples of patients and implants and with longer follow-up are needed to confirm these findings.
['Malchiodi|Luciano|L|', 'Moro|Tommaso|T|', 'Cattina|Diego P|DP|', 'Cucchi|Alessandro|A|http://orcid.org/0000-0001-5155-2807', 'Ghensi|Paolo|P|http://orcid.org/0000-0002-8444-0489', 'Nocini|Pier F|PF|']
D000328:Adult D000368:Aged D000369:Aged, 80 and over D016301:Alveolar Bone Loss D001862:Bone Resorption D059605:Dental Implant-Abutment Design D003758:Dental Implantation, Endosseous D015921:Dental Implants D019232:Dental Restoration Failure D005260:Female D006801:Humans D057893:Immediate Dental Implant Loading D007575:Jaw, Edentulous D008297:Male D008875:Middle Aged D011862:Radiography, Panoramic D012189:Retrospective Studies D016896:Treatment Outcome
edentulous jaw immediate loading cantilever full arch tilted implants