The Impact of Various Coronal Restoration Construction Techniques on the Fracture Resistance of Posterior Teeth: An In Vitro Study

Document Type : Original Article

Authors

1 Lecturer, Department of Conservative Dentistry, Faculty of Oral and Dental Medicine, Ahram Canadian University

2 Associate Professor, Department of Fixed Prosthodontics, Faculty of Oral and Dental Medicine, Ahram Canadian University

10.21608/edj.2025.406071.3561

Abstract

Objective: To determine the impact of different onlay construction methods (direct-indirect versus indirect CAD/CAM method) on the resistance to fracture of posterior teeth.
Materials and Methods: 30 intact maxillary permanent molars were randomly allocated into two groups, each including 15 specimens. All the teeth were prepared into Class II onlay restorations. Group C was restored with direct/indirect Ecosite bulk fill composite, while Group O was restored with Shofu CAD/CAM composite blocks. All samples were prepared and preserved in distilled water for one day. A fracture test was done by applying occlusal compressive load after completion of thermomechanical aging. Data were collected and statistically analysed.
Results: The Indirect Shofu group exhibited greater mean fracture load values compared to the Direct-Indirect group. This was statistically significant, as indicated by ANOVA and Tukey’s post-hoc testing (p = <0.0001 < 0.05).
Conclusion: Shofu composite blocks exhibited statistically significant superior fracture resistance compared to direct-indirect Ecosite Bulk Fill Composite.
Clinical significance: Indirect CAD/CAM onlay restorations for permanent molars outperformed direct-indirect resin composite onlays.

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