The International Journal of Oral & Maxillofacial Implants
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Int J Oral Maxillofac Implants 32 (2017), No. 6     21. Nov. 2017
Int J Oral Maxillofac Implants 30 (2015), No. 2  (26.03.2015)

Page 321-329, doi:10.11607/jomi.3892, PubMed:25830392


Digitally Produced Fiber-Reinforced Composite Substructures for Three-Unit Implant-Supported Fixed Dental Prostheses
Bonfante, Estevam A. / Suzuki, Marcelo / Carvalho, Ricardo M. / Hirata, Ronaldo / Lubelski, Will / Bonfante, Gerson / Pegoraro, Thiago A. / Coelho, Paulo G.
Purpose: This study aimed to evaluate the probability of survival, Weibull modulus, characteristic strength, and failure modes of computer-aided design/computer-assisted manufacture (CAD/CAM) fiber-reinforced composite (FRC) substructures used for implant-supported fixed dental prostheses (ISFDPs).
Materials and Methods: Three-unit ISFDPs (first molar pontic) fabricated as a monolithic composite piece or as composite veneered on a CAD/CAM FRC substructure with either a 12-mm2 or 3-mm2 connector area (n = 18 each) were subjected to step-stress accelerated life testing in water. Use-level probability Weibull curves and the probability of survival were calculated. Fractographic analysis was performed under polarized light and scanning electron microscopy.
Results: Fatigue did not accelerate the failure of any group, whereas prosthesis strength was the main factor in increased failure (β < 1). The probability Weibull contour plot showed no differences between the ISFDPs with 12 mm2 and the monolithic composite ISFDP in characteristic strength (η = 643.5 N and 742.7 N, respectively) or Weibull modulus (6.7 and 5.8, respectively), whereas both were significantly higher than 3 mm2 (444.91 N and 9.57). The probability of survival was not statistically different between groups at 100,000 mission cycles at 300 N. Differences were observed in fatigue failures above 800 N; monolithic composite ISFDPs failed catastrophically, whereas those with CAD/CAM FRC substructures presented veneer/composite cohesive or adhesive failures. Cracks evolved from the occlusal contact toward the margins of the cohesively failed composite, and in CAD/CAM FRC prostheses, competing failure modes of cracks developing at the connector area with those at the indentation contact were observed.
Conclusion: The probability of survival did not differ between CAD/CAM FRC with either 3-mm2 or 12-mm2 connector areas, monolithic composite, or metal-ceramic ISFDPs previously tested under the same methodology. However, differences in failure modes were detected between groups.

Keywords: computer-aided design/computer-assisted manufacture, fiber-reinforced composite, fixed dental prostheses, fatigue, Weibull
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