Calcium is more effective than acetaminophen in long-term pain reduction during orthodontic treatment.

Objective: Degree of Conversion (DC) of Resin-Based composites (RBCs) is a concern and is affected by different factors. This study was conducted to evaluate the effect of different thicknesses and storage times on DC of bulk-fill and universal RBCs using the FTIR method. Material and methods: For each of dental composite (Tetric N- Ceram Bulk Fill and Tetric N Ceram), 28 samples were prepared (14 samples with 2 mm height and 14 samples with 4 mm height). One and seven days (1d and 7d) after storage in an incubator at 37 ˚C, DC was measured and recorded using a FTIR device. Data were analyzed using t-test and Three-Way ANOVA and Tukey Post-Hoc Test. P < 0.05 was considered statistically significant. Results: DC of Bulk-fill composite is greater than universal composite. DC at 2 mm thickness is more than 4 mm. Unlike universal composite, 7d DC of Bulk-fill composite is greater than 1d. Of course, none of these differences are statistically significant (P-value > 0.05). Conclusions: Considering the limitation of this study, since no difference was found between DC of 1d and 7d, 1d DC is sufficient for clinical procedures, such as polishing, and the laboratory tests.KEYWORDSBulk-fill composites; Degree of Conversion; FTIR.

Background and aim: Using Stainless Steel Crowns (SSC) for Early Childhood Caries usually causes an unpleasant condition in the aesthetic of the patients. The aim of this study was to evaluate the effect of different surface treatments and bonding systems on shear bond strength of composite veneer to Stainless Steel Crown. Materials and Methods:In this in vitro study, 120 SSC were divided into 6 groups according to the surface treatment method (without surface treatment, diamond bur or sandblast) and bonding agent (alloy primer+Clearfil SE Bond or G Premio Bond). Shear Bond Strength (SBS) of composite cylinder to SSC was measured. Data were analyzed using ANOVA and Tukey. P-value <0.05 was considered statistically significant.Result: SBS with Alloy Primer+Clearfil SE Bond (37.53±9.13) was significantly higher than G Premio Bond ( 30.54± 12.34) (P-value <0.0001). Sandblast showed significantly higher SBS in comparison with two other groups (P-value <0.0001) Conclusion:Based on the results of this study, sandblasting has the highest SBS in comparison with the other methods of surface treatment. In the absence of sandblast, the application of the Alloy Primer+ Claerfil SE Bond on the SSC surface will provide better bond to resin composite.