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To achieve a durable composite-composite bond, it is highly recommended that besides selective grinding of the surface to be repaired, specific combinations of silane primer and bonding agent should be used, without the need for acid etching of the composite surface. SUMMARYObjective: This study evaluated the effectiveness of three surface treatments on repair shear bond strength (SBS) of aged composites.Methods: A total of 120 cylindrical samples made of a micro-hybrid composite (Clearfil AP-X) were randomly assigned to one control and three experimental groups (n¼30) after water storage (3 weeks). All experimental groups included surface roughening with diamond burs. Subsequent treatments were provided as follows: group 1-only (self-etching) bonding; group 2-silane and bonding; and group 3-phosphoric acid etching, silane, and bonding. The composites were repaired with the same brand and were aged (water storage [48 hours] and thermocycling [2000 cycles]). Each group was divided into two subgroups (each, n¼15): new-water storage at 378C for one week; old-water storage for six months. The

An in situ forming implant (ISFI) is a novel drug delivery system used for protein and peptide delivery, especially for cancer treatment. An ISFI based on 33% (w/w) poly(D,L-lactide-co-glycolide)(PLGA; 50:50)/3% (w/w) leuprolide acetate (LA)/64% (w/w) N-methyl-2-pyrrolidone (NMP) was prepared for this study. After injection of the final formulation, which is a viscous liquid to an aqueous medium, it deforms to become a semisolid or solid matrix. The performance of this matrix was investigated on the basis of peptide release from it. Erosion and morphology of ISFI were also studied. The effects of adding 12.8% (w/w) ethyl benzoate (EB) as a rate-modifying agent on performance, erosion, and morphology of ISFI were assessed. The implant containing EB showed very low burst release (5.53% ± 0.82%) and the morphology turns to closed pore-like structures. After adding EB, the morphology turns to closed pore-like structures. This type of morphology has very close relation to the performance of the implant as well. Finally, the effect of EB on performance, erosion, and morphology is explained by means of solvent-nonsolvent affinity, water permeation, and the rate of phase inversion.

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PURPOSEHeat of composite polymerization (HP) indicates setting efficacy and temperature increase of composite in clinical procedures. The purpose of this in vitro experimental study was to evaluate the effects of 5 temperatures on HP of two new composites.MATERIALS AND METHODSFrom each material (Core Max II [CM] and King Dental [KD]), 5 groups of 5 specimens each were prepared and their total HPs (J/gr) were measured and recorded, at one of the constant temperatures 0℃, 15℃, 23℃, 37℃ and 60℃ (2 × 5 × 5 specimens) using a differential scanning calorimetry (DSC) analyzer. The data were analyzed using a two-way ANOVA, a Tukey's test, an independent-samples t-test, and a linear regression analysis (α=0.05).RESULTSNo polymerization reactions occurred at 0℃; then this temperature was excluded from statistical analyses. The mean HP of the remaining 20 KD specimens was 20.5 ± 14.9 J/gr, while it was 40.7 ± 12.9 J/gr for CM. The independent-samples t-test showed that there were significant differences between the HP of the two materials at the temperatures 15℃ (P=.0001), 23℃ (P=.0163), 37℃ (P=.0039), and 60℃ (P=.0106). Linear regression analysis showed statistically significant correlations between environment temperatures and HP of CM (R2=0.777).CONCLUSIONUsing CM is advantageous over conventional composite because of its better polymerization capacity. However due to its high HP, further studies should assess its temperature increase in vivo. Preheating KD is recommended. Refrigerating composites can negatively affect their polymerization potential.