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Fracture Resistance of CAD/CAM‐Fabricated Lithium Disilicate MOD Inlays and Onlays with Various Cavity Preparation Designs
Author(s) -
Yoon HyungIn,
Sohn Paul J.,
Jin Sharon,
Elani Hawazin,
Lee Sang J.
Publication year - 2019
Publication title -
journal of prosthodontics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.902
H-Index - 60
eISSN - 1532-849X
pISSN - 1059-941X
DOI - 10.1111/jopr.12787
Subject(s) - inlay , lithium disilicate , fracture (geology) , dentistry , materials science , tooth fracture , orthodontics , composite material , ceramic , medicine
Purpose To examine the fracture resistance of premolars restored with CAD/CAM lithium disilicate mesio‐occlusal‐distal (MOD) inlays and onlays of different cavity designs. Materials and Methods Two widths of occlusal isthmus (75%, 100% of intercuspal distance) and three designs of cuspal coverage (none, palatal, complete) were used for the preparation of MOD inlays and onlays in the extracted maxillary premolars. Sixty lithium disilicate restorations were milled and bonded into the cavities. After 24 hours of water storage, the specimens were loaded until fracture, and the fracture loads (N) were measured. Any evidence of cracks and fractures on the tested specimens were examined to classify failure patterns. Results Mean fracture load values for the tested groups were as follows: 664.4 ± 214.7 N (group A), 659.3 ± 391.2 N (B), 681.9 ± 258.1 N (C), 938.1 ± 862.0 N (D), 841.7 ± 375.4 N (E), and 994.2 ± 486.3 N (F). The width of occlusal isthmus did not significantly affect the fracture loads among all the groups. Within groups with identical isthmus width, the fracture loads showed no significant difference depending on the designs of cuspal coverage. The majority of specimens showed either type III or IV fracture mode. Conclusions Within limitations of this study, the bonded restorations of premolars with CAD/CAM‐generated lithium disilicate were reliable, regardless of cavity preparation design.