Influence of cleaning methods after 3D printing on two-body wear and fracture load of resin-based temporary crown and bridge material.
OBJECTIVES
To investigate the impact of different cleaning methods on the fracture load and two-body wear of additively manufactured three-unit fixed dental prostheses (FDP) for long-term temporary use, compared to the respective outcomes of milled provisional PMMA FDPs.


MATERIALS AND METHODS
Shape congruent three-unit FDPs were 3D printed using three different resin-based materials [FPT, GCT, NMF] or milled [TEL] (N = 48, n = 16 per group). After printing, the FDPs were cleaned using: Isopropanol (ISO), Yellow Magic 7 (YEL), or centrifugal force (CEN). Chewing simulation was carried out with a vertical load of 50 N (480,000 × 5 °C/55 °C). Two-body wear and fracture load were measured. Data were analyzed using global univariate ANOVA with partial eta squared, Kruskal-Wallis H, Mann-Whitney U, and Spearman's rho test (p < 0.05).


RESULTS
TEL showed less wear resistance than FPT (p = 0.001) for all cleaning methods tested. Concerning vertical material loss, NMF and GCT were in the same range of value (p = 0.419-0.997), except within FDPs cleaned in ISO (p = 0.021). FPT showed no impact of cleaning method on wear resistance (p = 0.219-0.692). TEL (p < 0.001) showed the highest and FPT (p < 0.001) the lowest fracture load. Regarding the cleaning methods, specimens treated with ISO showed lower fracture load than specimens cleaned with CEN (p = 0.044) or YEL (p = 0.036).


CONCLUSIONS
The material selection and the cleaning method can have an impact on two-body wear and fracture load results.


CLINICAL RELEVANCE
Printed restorations showed superior two-body wear resistance compared to milled FDPs but lower fracture load values. Regarding cleaning methods, ISO showed a negative effect on fracture load compared to the other methods tested.
['Mayer|Johannes|J|http://orcid.org/0000-0003-4180-9212', 'Stawarczyk|Bogna|B|', 'Vogt|Konstantin|K|', 'Hickel|Reinhard|R|', 'Edelhoff|Daniel|D|', 'Reymus|Marcel|M|']
D003442:Crowns D003799:Dental Stress Analysis D008422:Materials Testing D066330:Printing, Three-Dimensional
Cleaning method 3D printing Two-body wear Fracture load Additive manufacturing Post-processing