Study on Fracture Resistance of Maxillary Premolars Restored with CAD/CAM Onlays and Crowns

doi:10.13701/j.cnki.kqyxyj.2023.08.012

Abstract

Abstract: Objective: To compare the fracture resistance of defected maxillary premolars restored with onlay and crown, respectively. Methods: Sixty-four maxillary first premolars with similar size and morphology were randomly divided into four groups (n=16). The following defect types were prepared respectively: group A had 1/3 defect of occlusal surface; group B had 1/2 defect of occlusal surface; group C had 1/3 defect of proximal-occlusal surface; and group D had 1/2 defect of proximal-occlusal surface. Each group was divided into two subgroups according to different restore methods (n=8), A1-D1 were restored by IPS e.max CAD onlays, and A2-D2 were restored by IPS e.max CAD crowns. The maximum loading value and failure mode were analyzed.Results: The maximum fracture resistance of onlays and crowns, i.e. (1203±148) N and (985±103) N, appeared in group A. Among onlay restoration groups, fracture resistances of group A1 and B1 were significantly higher than those of group C1 and D1 (P<0.05). Among crown restoration groups, fracture resistances of group A2 and B2 were significantly higher than those of group C2 and D2 (P<0.05), and C2 was significantly higher than D2 group (P<0.05). Within the same defect type, fracture resistances of onlays were significantly higher than those of crowns (P<0.05). There was no significant difference in the fracture mode among all groups (P>0.05).Conclusion: Defect types of premolar affect fracture resistance. For occlusal and proximal-occlusal defected premolars, fracture resistance of onlays was higher than that of crowns.

Key words: onlay, crown, maxillary premolar, fracture resistance

WU Jie, DA Yunmeng, ZHANG Zhao, YUAN Shuo, MA Xiaoping. Study on Fracture Resistance of Maxillary Premolars Restored with CAD/CAM Onlays and Crowns[J]. Journal of Oral Science Research, 2023, 39(8): 727-731.

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