Fracture resistance of simulated immature teeth reinforced with different composites after root-end closure

Abstract

Purpose The purpose of this study was to evaluate fracture resistance of simulated immature teeth reinforced with different bulk-fill flowable composite resin; Smart dentine replacement (SDR) or Filtek bulk-fill flowable (FBF) after application of two apical plug materials; mineral trioxide aggregate (MTA), or Biodentine (BD). Patients and methods Fifty human central incisors with nearly similar dimensions were used. Teeth were sectioned 3 mm above and 10 mm below cement–enamel junction to simulate immature apex. Root canal (RC) instrumentation was done using ProTaper rotary system up to F5; simulations of immature roots were carried out using Peeso-reamers from #1 to #4. Teeth were divided randomly into five groups (n = 10), group 1 (control): received no filling material, group 2: MTA/SDR, group 3: MTA/FBF, group 4: BD/SDR, and group 5: BD/FBF. In the experimental groups, MTA or BD was placed in the apical 4 mm of RCs. The remaining part of RCs was back-filled with composite resins. A load was applied on the palatal surface of teeth at 135° to their long axis until fracture using universal testing machine. Load was recorded in Newton and data were analyzed using one-way analysis of variance at a significant level of P less than or equal to 0.05. Results Group 4 exhibited the highest fracture resistance mean value followed by groups 2, 5, and 3, whereas control group exhibited the lowest value. A statistical significant difference between SDR and FBF groups was recorded, whereas there was no statistical significant difference between MTA and BD groups. Conclusion Using either MTA or BD as an apical plug material with bulk-fill flowable composite resins in simulated immature teeth enhances their fracture resistance. SDR provided better resistance to fracture than FBF.