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Effect of Inlays, Onlays and Endocrown Cavity Design Preparation on Fracture Resistance and Fracture Mode of Endodontically Treated Teeth: An In Vitro Study
Author(s) -
Kassis Cynthia,
Khoury Pierre,
Mehanna Carina Z,
Baba Nadim Z.,
Bou Chebel Fadi,
Daou Maha,
Hardan Louis
Publication year - 2021
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.13294
Subject(s) - inlay , molar , universal testing machine , pulp (tooth) , dentistry , materials science , tooth fracture , orthodontics , medicine , composite material , ultimate tensile strength
Purpose To evaluate the fracture resistance and failure modes of endodontically treated mandibular molars restored with different designs of inlays, onlays and endocrowns. Materials and Methods Extracted mandibular third molars (n = 180) were used. An access cavity was prepared on the occlusal surface of each tooth and the roots were obturated with gutta percha. All specimens were randomly divided into 6 groups (n = 30/group) according to the cavity design and the restoration material used. C: control group without access cavity preparation. IE: MOD inlay preparation with EverX Posterior (GC Europe) in the pulp chamber. IG: MOD inlay preparation with G‐aenial Universal Flo (GC America) in the pulp chamber. OE: onlay preparation with EverX Posterior (GC Europe) in the pulp chamber. OG: onlay preparation with G‐aenial Universal Flo (GC America) in the pulp chamber. EC: endocrown with an empty pulp chamber. All restorations were fabricated with CAD/CAM system using CERASMART ® (GC Dental products Europe, Belgium) CAD/CAM blocks. Specimens were thermal‐cycled and were subjected to a compressive load applied at 30° angle relative to the long axis of the tooth with a universal testing machine. Results were statistically analyzed by ANOVA followed by Tukey post hoc tests. Chi‐square test and Fisher Exact tests were used for the comparisons among groups. Results The mean fracture strength was significantly different between the groups ( p < 0.001); it was significantly highest for intact teeth, followed by endocrowns ( p = 0.021). The strength was significantly lower for inlays (with G‐aenial Universal Flo and EverX Posterior), intermediate for onlays with EverX Posterior followed by onlays with G‐aenial Universal Flo. Conclusions Endocrowns exhibited higher fracture resistance than other tested composite resin groups. Endocrowns and onlays showed a more favorable failure mode than inlay restorations.