DOI: 10.4103/jicdro.jicdro_55_25 ISSN: 2231-0754

Influence of Endodontic Access Cavity Design on Fracture Strength of Teeth Restored with Bulk-fill and Fiber-reinforced Composites: An In vitro Study

Sakshi Sharad Agrawal, S. R. Srinidhi, Sourabh S. Barbhai, Ayush A. Agarwal, Muskan Dilip Hinduja
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Background:

Preservation of tooth structure during endodontic access cavity preparation has gained importance due to its influence on the fracture resistance of endodontically treated teeth. Conservative access designs, such as the truss endodontic cavity, aim to preserve critical dentin, while advances in restorative materials, including bulk-fill and fiber-reinforced composites, may further modify fracture behavior.

Objective:

The objective is to evaluate and compare the fracture resistance of teeth prepared with conventional and truss endodontic access cavity designs and restored using bulk-fill and fiber-reinforced composite liners.

Materials and Methods:

Sixty extracted intact human mandibular first molars were selected and randomly allocated into four groups ( n = 15): Group 1 - conventional access cavity preparation (CEC) restored with bulk-fill flowable composite liner; Group 2 - CEC restored with fiber-reinforced flowable composite liner; Group 3 - Truss access cavity (TEC) restored with bulk-fill flowable composite liner; and Group 4 - TEC restored with fiber-reinforced flowable composite liner. All access cavities were definitively restored with Filtek Z-350 nanohybrid composite resin. Fracture resistance testing was performed using a universal testing machine by applying a compressive load with a 6-mm diameter spherical indenter at a 15° angle to the central fossa at a crosshead speed of 1 mm/min until fracture. Data were analyzed using one-way analysis of variance, followed by post hoc Tukey’s test ( P < 0.001).

Results:

The highest mean fracture resistance was observed in teeth restored with fiber-reinforced composite liner in TEC (Group 4), followed by fiber-reinforced composite liner in CEC (Group 2), bulk-fill liner in TEC (Group 3), and bulk-fill liner in CEC (Group 1).

Conclusion:

Within the limitations of this in vitro study, TEC preparation demonstrated greater fracture resistance compared with CEC. Fiber-reinforced composite liners showed superior fracture resistance compared with bulk-fill flowable composite liners, irrespective of access cavity design.

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