TY - JOUR T1 - [Effect of occlusal thickness design on the fracture resistance of endocrowns restored with lithium disilicate ceramic and zirconia]. AU - Lin,Zhen-Xiang, AU - Pan,Zai-Xing, AU - Ye,Qi-Qing, AU - Zheng,Zhi-Qiang, AU - Lin,Jie, PY - 2020/12/30/entrez PY - 2020/12/31/pubmed PY - 2021/1/1/medline KW - endocrown KW - fracture resistance KW - lithium disilicate ceramic KW - retainer KW - thickness KW - zirconia SP - 647 EP - 651 JF - Hua xi kou qiang yi xue za zhi = Huaxi kouqiang yixue zazhi = West China journal of stomatology JO - Hua Xi Kou Qiang Yi Xue Za Zhi VL - 38 IS - 6 N2 - OBJECTIVE: This study aimed to investigate the effect of occlusal thickness design on fracture resistance of endocrowns restored with lithium disilicate ceramic and zirconia. METHODS: A total of 24 artificial first mandibular molars were randomly divided into four groups with six teeth in each group as follows: group lithium disilicate ceramic-2 mm (lithium disilicate ceramic, with an occlusal thickness of 2 mm and a retainer length of 4 mm); group lithium disilicate ceramic-4 mm (lithium disilicate ceramic, with an occlusal thickness of 4 mm and a retainer length of 2 mm); group zirconia-2 mm (zirconia, with an occlusal thickness of 2 mm and a retainer length of 4 mm); and group zirconia-4 mm (zirconia, with an occlusal thickness of 4 mm and a retainer length of 2 mm). After adhesive cementation (RelyX Ultimate Clicker), all specimens were subjected to thermocycling (10 000 cycles). The specimens were subjected to fracture resistance testing at a 135° angle to the teeth at a crosshead speed of 0.5 mm·min⁻¹ in a universal testing machine. Data were analyzed with ANOVA and Tukey's HSD test by SPSS 15.0. The failure modes were classified. RESULTS: The fracture resistances of groups lithium disilicate ceramic- 2 mm, lithium disilicate ceramic-4 mm, zirconia-2 mm, and zirconia-4 mm were (890.54±83.41), (2 320.87±728.57), (2 258.05±557.66), and (3 847.70±495.99) N respectively. Group zirconia-4 mm had the highest fracture resistance, whereas group lithium disilicate ceramic-2 mm had the lowest. CONCLUSIONS: The fracture resistance of molar endocrown with zirconia is higher than that with lithium disilicate ceramic. Increasing the occlusal thickness can improve the fracture resistance but increase the risk of fracture of abutment. SN - 2618-0456 UR - https://www.unboundmedicine.com/medline/citation/33377341/[Effect_of_occlusal_thickness_design_on_the_fracture_resistance_of_endocrowns_restored_with_lithium_disilicate_ceramic_and_zirconia]_ DB - PRIME DP - Unbound Medicine ER -