Fracture resistance and failure pattern of three different onlays restorations for endodontically treated premolars
ZHAN Chun-hua
LIU Bing
HUANG Xing-yan
FENG Li-chang
Abstract：AIM:To compare the fracture resistance and modes of failures of three different aesthetic MOD onlays on endodontically treated premolars. METHODS:50 sound maxillary premolars were selected,10 untreated teeth were used as the controls.The other 40 premolars were subjected to standardized MOD onlay preparation and root canal treatment and divided into 4 groups(n＝10). Onlays of indirect composite and lithium disilicate ceramic were re-spectively prepared for the restoration of the MOD cavity of groupⅠandⅡ,onlays of Full Zirconiafor for groupⅢandⅣ. In groupⅠ,ⅡandⅢbuccal and palatal cusps were reduced by 2 mm,and in groupⅣby 1 mm. All onlays were cemented using Multilink Automix. All the samples of the 5 groups were subjected to fracture resistance test on univer-sal testing machine. The fractured surfaces were observed under stereo-microscope. RESULTS:The fracture resist-ance(N)of group control,Ⅰ,Ⅱ,Ⅲ and Ⅳ was 1 135.92 ± 228.61,687.58 ± 107.66,705.41 ± 203.78, 1 572.84 ± 243.53 and 1 012.65 ± 193.80 respectively (groupⅢvs the other groups,P＜0.05;groupⅠ,ⅡorⅣvs the control,P＞0.05). No crack was observed in the restorations of group Ⅲ. The restorations of group Ⅰ and Ⅱshowed mainly type E fracture mode followed by type B;those of groupⅢandⅣshowed mainly type A fracture mode. CONCLUSION:Full zirconia MOD onlay has higher fracture resistance for endodontically treated premolars than the other MOD systems.
Keywords：CAD/CAMzirconialithium disilicateindirect compositeonlay
Publication Date：2018-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：5( 332-335,344 )