Fatigue and fracture resistance of minimally invasive ceramic and resin composite veneers with different designs bonded adhesively to severely eroded teeth

摘要

This study evaluated the load bearing capacity of minimal invasive restoration alternatives on severely worn teeth after cyclic loading. Sound human maxillary incisors (N=72, n=9 per group) were randomly divided into nine experimental groups to receive one of the following restoration types: Group 1: Intact tooth, Group 2: Direct resin composite, Group 3: Lingual: Indirect resin composite, Labial: Ceramic veneer with lingual overlap, Group 4: Lingual: Indirect resin composite with lingual overlap, Labial: Ceramic, Group 5: Lingual: Direct composite, Labial: Ceramic, Group 6: Lingual: Feldspathic Ceramic, Labial: Feldspathic ceramic, Group 7: Lithium disilicate crown, Group 8: Metal-ceramic crown. Teeth were prepared simulating erosion/wear conditions. Specimens were subjected to cyclic loading (1,200,000 cycles, 5-55 degrees C) and then loaded to failure from the lingual surface at 105 degrees inclination (1mm/min). Data (Newton) were analyzed using one-way ANOVA, Tukey`s tests and Weibull moduli were calculated (=0.05). Significant differences were observed between the groups for the initial (p=0.006) and maximum fracture load (p=0.002). Group 3 (55 +/- 36) presented significantly lower initial fracture load compared to other groups (79 +/- 35-134 +/- 36) (p<0.05). When maximum fracture load is considered, control group (1) (602 +/- 355) and from restored groups 2 (449 +/- 144) and 4 (495 +/- 291) showed significantly higher results (p<0.05). Weibull modulus for the maximum fracture load was the highest for Group 2 (m=3.47) among all groups (m=1.61-4.18). Groups 2, 3, 6 presented the highest incidence of repairable failures. Based on the results, severely worn teeth could be restored with lingual direct resin composite and labial veneering with indirect resin with overlap.