Bond strength of conventional versus modified methods for Class IV restorations in primary incisors: An in vitro study.

Background. Aesthetic restorations of severely decayed anterior primary teeth are challenging due to the small size of the teeth and the large pulp chambers. Therefore, this study evaluated and compared the tensile and shear bond strengths of conventional versus modified methods (slot technique) of Cl IV restorations in primary incisors. Methods. A total of 120 extracted intact maxillary primary central and lateral incisors were divided into two groups. In group A, conventional Cl IV cavities were prepared. In group B, after conventional cavity preparation, four and three incisal slots were prepared on the incisal edges of the central and lateral incisors, respectively. All the teeth were restored using composite resin, and then the tensile and shear bond strengths were evaluated. Results. A statistically significant increase in the tensile bond strength of restorations was recorded in the modified technique compared to the conventional method (P=0.001). Although an increase in the shear bond strengths was found in the modified method, the value did not reach a statistically significant level (P=0.158). The most frequent fracture type was adhesive in the conventional group and cohesive in the modified group, considering the tensile and shear bond strength tests. In both groups, the highest average tensile bond strength was recorded in teeth with the cohesive fracture in dentin, and the lowest average was seen in the adhesive type. Conclusions. Incisal slots could increase the tensile bond strengths of Cl IV composite resin restorations in primary teeth.

Clinical and radiographic comparison of Biodentine and Formocresol: an updated meta-analysis with trial sequential analysis.

PURPOSE: This meta-analysis aimed to compare the clinical and radiographic success rate of Biodentine as an alternative to Formocresol to provide a critical appraisal of the available literature and evidence-based conclusion as well as update the previous systematic review. METHODS: MEDLINE, CENTRAL, Web of Science, Scopus, and Google Scholar databases were searched up to 20 October 2021 to identify RCTs evaluating pulpotomy with Biodentine/Formocresol in carious primary molars among children ≤ 10 years old. The risk of bias was assessed using the Cochrane RoB-2 tool. RRs and corresponding 95% CIs were calculated to pool results that RR Ëƒ 1 indicated a higher success rate in the Biodentine group and RR < 1 indicated a higher success rate in the Formocresol group. Heterogeneity was calculated using the I2 and τ2 statistics. In addition, trial sequential analysis was performed to adjust results for type I and type II errors and evaluate power of the meta-analysis. RESULTS: Nine RCTs were identified and eight RCTs were included in the meta-analysis and trial sequential analysis. The obtained evidence showed no significant difference between Biodentine and Formocresol in terms of clinical efficacy. However, considering the radiographic success rate the results of the meta-analysis and trial sequential analysis significantly favoured Biodentine. CONCLUSION: Within the limitations of the present review and based on the retrieved findings it has been clearly shown that Biodentine is superior compared to Formocresol in terms of radiographic success rate with firm evidence in this regard. Although the performed meta-analysis showed no significant clinical difference between Biodentine and Formocresol, however, trial sequential analysis revealed a lack of firm evidence in this regard.

Osteogenic/Odontogenic Bioengineering with co-Administration of Simvastatin and Hydroxyapatite on Poly Caprolactone Based Nanofibrous Scaffold.

Purpose: Statin is an effective factor for promoting osteogenesis. The aim of the present study was to evaluate the effect of simvastatin (SIM) and/or HA addition on changes in osteogenesis levels by human DPSCs transferred onto three-dimensional (3D) nanofibrous Poly (ε-caprolactone) (PCL)/Poly lactic acide (PLLA) polymeric scaffolds. Methods: For this purpose, a 3D nanofibrous composite scaffold of PCL/PLLA/HA was prepared by electrospinning method. SIM was added to scaffolds during DPSCs culturing step. Cell proliferation and osteogenic activity levels were assessed by using MTT assay and Alizarin Red assay methods. In addition, the expression of genes responsible for osteogenesis, including BMP2, Osteocalcin, DSPP and RUNX2, were determined before and 2 weeks after incorporation of SIM. Results: The MTT assay showed that PCL/PLLA/HA scaffolds seeded with DPSCs has significant (p<0.05) more proliferative effect than PCL/PLLA or DMEM cultured cells, additionally SIM administration improved this result over the PCL/PLLA/HA scaffolds without SIM treatment. SEM imaging revealed improved adhesion and probably osteogenic differentiation of DPSCs on PCL/PLLA/HA nanofibers treated with SIM, moreover the alizarin red assay ensured significant (p<0.05) higher mineralization of this group. Finally, real time PCR confirmed the positive regulation (P<0.05) of the expression of osteo/odontogenesis markers BMP2, Osteocalcin, DSPP and RUNX2 genes in PLLA-PCL-HA (0.1)-SIM group. Conclusion: As a result, addition of simvastatin with incorporation of hydroxyapatite in PCL-PLLA scaffolds might increase the expression of osteogenesis markers in the DPSCs, with a possible increase in cell differentiation and bone formation.

A new simulated plasma for assessing the solubility of mineral trioxide aggregate.

INTRODUCTION: Solubility of mineral trioxide aggregate (MTA) is an important characteristic that affects other properties such as microleakage and biocompatibility. Distilled water (DW) has previously been used for solubility tests. This experimental study compared the solubility of MTA in DW, synthetic tissue fluid (STF) and new simulated plasma (SP). METHODS AND MATERIALS: In this study, 36 samples of tooth-colored ProRoot MTA were prepared and divided into three groups (n=12) to be immersed in three different solutions (DW, STF, and SP). Solubility tests were conducted at 2, 5, 9, 14, 21, 30, 50, and 78-day intervals. The unequal variance F-test (Welch test) was utilized to determine the effect of solubility media and Games-Howell analysis was used for pairwise comparisons. The repeated-measures ANOVA was used to assess the importance of immersion duration. RESULTS: Welch test showed significant differences in solubility rates of samples between all the different solubility media at all the study intervals (P<0.05) except for the 14-day interval (P=0.094). The mixed repeated-measures ANOVA revealed a significant difference in solubility rate of MTA in three different solutions at all time-intervals (P=0.000). Games-Howell post-hoc test revealed that all pairwise comparisons were statistically significant at all time-intervals (P=0.000). CONCLUSION: Based on the findings of this study, the long-term solubility of MTA in simulated plasma was less than that in synthetic tissue fluid and distilled water.