Elisa Donaria Aboucauch Grassi1, Guilherme Schmitt de Andrade1, João Paulo Mendes Tribst2, Renan Vaz Machry3, Luiz Felipe Valandro3, Nathalia de Carvalho Ramos4, Eduardo Bresciani5, Guilherme de Siqueira Ferreira Anzaloni Saavedra6. 1. Department of Dental Materials and Prosthodontics, Institute of Science and Technology, São Paulo State University (Unesp), 777th Eng. Francisco José Longo Av., São José dos Campos, SP, 12245-000, Brazil. 2. Post-Graduate Program in Dentistry, University of Taubaté (UNITAU), 09th Rua Dos Operários St., Taubaté, SP, 12020-340, Brazil. 3. Graduate Program of Oral Science, Prosthodontics Unit, School of Dentistry, Federal University of Santa Maria (UFSM), Roraima Av, Santa Maria, RS, 100097105-340, Brazil. 4. School of Dentistry, São Francisco University (USF), 218th São Francisco de Assis Av., Bragança Paulista, SP, 12916-900, Brazil. 5. Department of Restorative Dentistry, Institute of Science and Technology, São Paulo State University (Unesp), 777th Eng. Francisco José Longo Av., São José dos Campos, SP, 12245-000, Brazil. 6. Department of Dental Materials and Prosthodontics, Institute of Science and Technology, São Paulo State University (Unesp), 777th Eng. Francisco José Longo Av., São José dos Campos, SP, 12245-000, Brazil. guilherme.saavedra@unesp.br.
Abstract
OBJECTIVES: This study evaluated the effect of deep margin elevation (DME) and restorative materials (leucite-reinforced glass-ceramics [C] vs. indirect resin composite [R]) on the fatigue behavior and stress distribution of maxillary molars with 2-mm deep proximal margins restored with MOD inlay. METHODS: Fifty-two extracted human third molars were randomly assigned into four groups (n = 13): C; DME + C; R; and DME + R. Inlays were fabricated in CAD-CAM and bonded to all teeth. The fatigue behavior was assessed with the stepwise stress test (10,000 cycles/step; step = 50 N; 20 Hz; initial load = 200 N). Fatigue failure loads and the number of cycles were analyzed with 2-way ANOVA and Tukey's test (p < 0.05) and Kaplan-Meier survival plots. The stress distribution was assessed with finite element analysis. The models were considered isotropic, linear, and homogeneous, and presented bonded contacts. A tripod axial load (400 N) was applied to the occlusal surface. The stress distribution was analyzed with the maximum principal stress criterion. RESULTS: For fatigue, there was no difference for DME factor (p > 0.05). For the material factor, the load and number of cycles for failure were statistically higher in the R groups (p < 0.05). The finite element analysis showed that resin composite inlays concentrated more stress in the tooth structure, while ceramic inlays concentrated more stress in the restoration. Non-reparable failures were more frequent in the resin composite inlays groups. CONCLUSIONS: DME was not negative for fatigue and biomechanical behaviors. Resin composite inlays were more resistant to the fatigue test, although the failure mode was more aggressive. CLINICAL SIGNIFICANCE: DME does not impair mechanical behavior. Resin composite inlays failed at higher loads but with a more aggressive failure mode.
OBJECTIVES: This study evaluated the effect of deep margin elevation (DME) and restorative materials (leucite-reinforced glass-ceramics [C] vs. indirect resin composite [R]) on the fatigue behavior and stress distribution of maxillary molars with 2-mm deep proximal margins restored with MOD inlay. METHODS: Fifty-two extracted human third molars were randomly assigned into four groups (n = 13): C; DME + C; R; and DME + R. Inlays were fabricated in CAD-CAM and bonded to all teeth. The fatigue behavior was assessed with the stepwise stress test (10,000 cycles/step; step = 50 N; 20 Hz; initial load = 200 N). Fatigue failure loads and the number of cycles were analyzed with 2-way ANOVA and Tukey's test (p < 0.05) and Kaplan-Meier survival plots. The stress distribution was assessed with finite element analysis. The models were considered isotropic, linear, and homogeneous, and presented bonded contacts. A tripod axial load (400 N) was applied to the occlusal surface. The stress distribution was analyzed with the maximum principal stress criterion. RESULTS: For fatigue, there was no difference for DME factor (p > 0.05). For the material factor, the load and number of cycles for failure were statistically higher in the R groups (p < 0.05). The finite element analysis showed that resin composite inlays concentrated more stress in the tooth structure, while ceramic inlays concentrated more stress in the restoration. Non-reparable failures were more frequent in the resin composite inlays groups. CONCLUSIONS: DME was not negative for fatigue and biomechanical behaviors. Resin composite inlays were more resistant to the fatigue test, although the failure mode was more aggressive. CLINICAL SIGNIFICANCE: DME does not impair mechanical behavior. Resin composite inlays failed at higher loads but with a more aggressive failure mode.
Authors: Roland Frankenberger; Julia Hehn; Jan Hajtó; Norbert Krämer; Michael Naumann; Andreas Koch; Matthias J Roggendorf Journal: Clin Oral Investig Date: 2012-02-23 Impact factor: 3.573
Authors: Veronika Müller; Karl-Heinz Friedl; Katrin Friedl; Sebastian Hahnel; Gerhard Handel; Reinhold Lang Journal: Clin Oral Investig Date: 2016-08-09 Impact factor: 3.573