Shear Bond Strength of Zirconia Ceramic to the Primary Tooth Dentin

Background: There is no information about the shear bond strengths (SBS) of zirconia ceramic to primary tooth dentin. Aim: To investigate the effect of different surface treatments and cements on the shear bond strength (SBS) of zirconia ceramic to primary tooth dentin. Materials and Methods: Prepared zirconia bars were distributed into four groups according to surface treatment procedure: control, sandblasting, CoJet and hot etching. The zirconia specimens in each group were further divided into subgroups according to cement (n = 13): self‑adhesive resin (Rely‑X Unicem), resin‑modified glass ionomer (Ketac‑Cem Plus), and universal bioactive (BioCem). Zirconia specimens were bonded to the primary tooth dentin surface by cement. SBS was measured, and the data were subjected to two‑way ANOVA and Tukey’s tests. Results: Statistical differences were observed in the surface treatment procedures for Rely‑X Unicem (P < 0.05), but no statistically significant differences were found in the sandblasting, CoJet and hot‑etching groups for Ketac‑Cem Plus (P > 0.05). For BioCem, the SBS value for the hot etching group was significantly lower than those for the CoJet and sandblasting groups (P < 0.05). The SBS values for the Rely‑X Unicem subgroups (sandblasting, CoJet and hot etching) were significantly higher than those for the other cements (P<0.05). Conclusion: The bond strength of zirconia ceramic to primary tooth dentin is affected by surface treatments and cements

Comparative evaluation of mineral trioxide aggregate and bioaggregate as apical barrier material in traumatized nonvital, immature teeth: A clinical pilot study

Background: Clinical research examining the use of mineral trioxide aggregate (MTA) as an apical  barrier material are limited, and no studies have so far examined the clinical performance of BioAggregate  as apical barrier material in nonvital immature teeth.Aim: This study was aimed to provide a comparative evaluation of the clinical and radiographic success of MTA and BioAggregate as an apical barrier material in children with traumatized nonvital, immature  permanent maxillary incisors.Subjects and Methods: A total of 26 maxillary incisor teeth in 20 children aged 7.11 were chosen for this study. Teeth were randomly divided into two groups according to the material to be applied, and the apical barrier was performed. Following treatment, for 24.month, teeth were clinically and radiographically evaluated once every 3..and 6.month, respectively.Results: All teeth treated with MTA and BioAggregate were clinically and radiographically successful throughout the 24.month follow.up period.Conclusions: Similar success was achieved in the apical barrier that using BioAggregate and MTA. BioAggregate would be considered suitable materials for apical barrier technique and can be used as an alternative to MTA.Key words: Apical barrier, BioAggregate, mineral trioxide aggregat

Effect of different topical fluoride applications on the surface roughness of a colored compomer

OBJECTIVE: The aim of this study was to evaluate the effect of neutral sodium fluoride (NNaF) gel and acidulated phosphate fluoride (APF) gel on the surface roughness of colored compomer (Twinky Star), conventional compomer (Compoglass F) and resin-modified glass-ionomer cement (RMGIC) (Photac-Fil). MATERIAL AND METHODS: A total of 45 standardized disc-shaped specimens were prepared for each material. After 24 h, finishing and polishing of specimens were done with aluminum oxide disc. Surface treatments with topical fluoride agents or distilled water (control) were performed four times, and interspersed with 8 pH cycles, simulating high cariogenic challenges. After the treatment, the surface roughness (Ra) was determined using a profilometer. In each group, specimens with Ra closest to the mean were examined with a scanning electron microscope (SEM) at ×1,000 and ×3,500 magnifications. Two-way ANOVA was used to evaluate Ra measurements, and the differences in Ra values between subgroups for each material and each topical applications were compared by Tukey's highly significant difference pairwise comparisons. RESULTS: No statistically significant difference in Ra between the Twinky Star and Compoglass F was found. However, Photac Fil showed significantly higher Ra than these materials after all surface treatments. There was a general trend of Ra increase from controls to NNaF and APF gels for all materials. SEM observations revealed that the surface micromorphology of Twinky-Star did not differ significantly from that of Compoglass F. CONCLUSION: Both the compomers and the RMGIC showed significantly higher surface roughness when subjected to APF gel application