Biomechanic of Endodontically Treated Molars Restored With Composite Resin Techniques

Objectives: The aim of this study was to evaluate the fracture strength and cusp strain of endodontically treated molars restored with different techniques and materials such as "bulk fill" flow and regular past or conventional resin composites.
Methods: Forty (40) lower human molars were received mesio-occlusal-distal (MOD) cavities, were endodontically treated and restored with the following protocols: 1) "Bulk fill" flow - SDR (Dentsply) in the pulp chamber (PC) and in coronal section (CS) in increment of up to 4,0 mm plus conventional TPH3 resin composite (Dentsply) to reconstruct the enamel (2.0 mm); 2) "bulk fill" Regular Filtek Posterior (3M Espe) restoring the entire cavity in increments up to 5.0mm; 3) Glass ionomer, Vitremer (3M-Espe) in the PC, and CS restored incrementally using Filtek Z350 XT (3M Espe); 4) Glass ionomer Vitremer (3M-Espe) in PC, and CS restored incrementally with TPH3 resin composite (Dentsply). Cusp strain was evaluated during restorative procedure and fracture test by strain-gage and fracture strength by compression test after fatigue aging. Data were analyzed statistically using One-way ANOVA (a = 5%).
Results: The lingual cusps resulted in greater deformation than the buccal cusp, irrespective of the restorative technique and moment of measurement. No significant difference was found for fracture resistance and values (P> 0.5).
Conclusions: It is concluded that the use of glass ionomer cement into the pulp chamber, which may facilitate the endodontic access, did not modify the biomechanical performance of molar teeth restored with bulk fill or incremental composite resin restorations.