Comparison of fracture resistance of simulated immature teeth using four different commercially available apexification materials - An in vitro study.

Introduction: The aim of this study was to compare the fracture resistance of simulated immature teeth using four different apical plug materials, i.e. Pro- Root MTA, Neo- MTA Plus, Biodentine, and Bioactive Glass. Materials and Methods: 80 extracted human maxillary anterior teeth were divided into 4 groups for this study. They were prepared using Peeso reamers to simulate immature teeth and to mimic Cvek's stage 3 of root development. A 5 mm apical barrier was placed using different materials. The remaining canal was obturated using gutta-percha and AH plus sealer. The final samples were stored at 37°C and 100% humidity for 4 weeks. Fracture resistance of the teeth was measured in Newtons using a universal testing machine. The comparison of fracture resistance between the four groups was done using Kruskal Walis ANOVA followed by post hoc Mann Whitney U test for pairwise comparison. Results: Biodentine group showed the highest fracture resistance as compared to the other three groups and the difference was highly significant (P < 0.001). Conclusions: Biodentine can be advocated over MTA as an effective material for the management of teeth with wide open apex. Bioactive glass also has shown promising results in increasing the fracture resistance of simulated immature teeth.

Effect of salivary contamination on the bond strength of total-etch and self-etch adhesive systems: an in vitro study.

AIM: To evaluate the influence of salivary contamination during dentin bonding procedures on shear bond strength and to investigate the effect of contaminant-removing treatments on the recovery of bond strength for two dentin-bonding agents. MATERIALS AND METHODS: Seventy-seven human maxillary and mandibular molars were randomly divided into two groups for total-etch adhesive (Single bond-3M ESPE, USA) and self-etch primer (UniFil Bond-GC, Tokyo, Japan) and subjected to contamination with saliva. The data for each group were subjected to one-way analysis of variance (ANOVA) followed by the Student Newman-Keuls test to make comparisons among the groups (p < 0.05). RESULTS: Salivary contamination had less adverse effect on the shear bond strength of single bond total-etch adhesive when it was blot dried or washed. UniFil bond was tolerant of salivary contamination, except when contamination occurred after application of the primer. CONCLUSION: In single bond adhesive, when the etched surface is contaminated by saliva, blotting the surface and applying the primer can recover the bond strength. Complete drying of the salivary contaminated surface should be avoided. In the UniFil bond groups, the repriming treatment (UF-V and UF-VI) resulted in the recovery of shear bond strength in the specimens contaminated after priming. CLINICAL SIGNIFICANCE: The results of this study showed that total- etch adhesive (single bond) was not affected by salivary contamination on the etched surface when the bonding surface was kept moist. Self-etch adhesive (UniFil bond) also tolerated salivary contamination except when the contamination occurred after application of the primer.