Comparative study of processing methods for starch/gelatin films

In this work, the influence of processing methods on the properties of starch/gelatin films plasticized with glycerol and sorbitol is reported. Four different processing techniques: casting; pressing; pressing followed by blowing and extrusion followed by blowing were evaluated. Bioplastics prepared by casting were homogeneous and transparent with lower opacity and water vapor permeability (WVP) values when compared to films prepared by other techniques. Among the cast films studied, those with 3% lipophilic starch, in 1:1 proportions and plasticized with sorbitol, showed lower WVP values and higher tensile strength (TS). Films obtained by pressing and blowing showed little expansion during blow, had cracks in the surface, low TS and higher WVP. These films were the only samples to show crystallinity as determined by thermal analysis and X-ray diffraction. In conclusion, different processing techniques have significantly affected the properties of these films. (C) Crown Copyright 2013 Published by Elsevier Ltd. All rights reserved.95268168

Influence of chlorhexidine application on longitudinal adhesive bond strength in deciduous teeth

The aim of this study was to evaluate the influence of applying 2% chlorhexidine for 30 seconds after phosphoric acid conditioning of dentin on the immediate and long-term bond strengths in deciduous teeth. The occlusal enamel was removed from 40 human sound deciduous molars, which were exfoliated by natural means, and the dentin was conditioned with 37% phosphoric acid for 15 seconds and washed with running water. The specimens were divided into two groups of 20 teeth. The test group received an application of 2% chlorhexidine for 30 seconds prior to a three-step etch-and-rinse adhesive system, whereas the control group received only the adhesive system. Three cylindrical restorations were made with a composite resin for each tooth. Ten teeth in each group were submitted to a microshear bond strength test after 24 hours, while the remaining teeth were stored in distilled water at 37 °C for 6 months before testing the microshear bond strength. The test group had a higher bond strength than did the control group after 6 months of storage. No statistical differences were found when groups with the same dentin treatment were compared at different times. Short applications of chlorhexidine at low concentrations prevent hybrid layer degradation and positively affect bond strength over time

Effect on adhesion of a nanocapsules-loaded adhesive system

Abstract This study aimed to evaluate the in situ degree of conversion, contact angle, and immediate and long-term bond strengths of a commercial primer and an experimental adhesive containing indomethacin- and triclosan-loaded nanocapsules (NCs). The indomethacin- and triclosan-loaded NCs, which promote anti-inflammatory and antibacterial effects through controlled release, were incorporated into the primer at a concentration of 2% and in the adhesive at concentrations of 1, 2, 5, and 10%. The in situ degree of conversion (DC, n=3) was evaluated by micro-Raman spectroscopy. The contact angle of the primer and adhesive on the dentin surface (n = 3) was determined by an optical tensiometer. For the microtensile bond strength µTBS test (12 teeth per group), stick-shaped specimens were tested under tensile stress immediately after preparation and after storage in water for 1 year. The data were analyzed using two-way ANOVA, three-way ANOVA and Tukey’s post hoc tests with α=0.05. The use of the NC-loaded adhesive resulted in a higher in situ degree of conversion. The DC values varied from 75.07 ± 8.83% to 96.18 ± 0.87%. The use of NCs in only the adhesive up to a concentration of 5% had no influence on the bond strength. The contact angle of the primer remained the same with and without NCs. The use of both the primer and adhesive with NCs (for all concentrations) resulted in a higher contact angle of the adhesive. The longitudinal μTBS was inversely proportional to the concentration of NCs in the adhesive system, exhibiting decreasing values for the groups with primer containing NCs and adhesives with increasing concentrations of NCs. Adhesives containing up to 5% of nanocapsules and primer with no NCs maintained the in situ degree of conversion, contact angle, and immediate and long-term bond strengths. Therefore, the NC-loaded adhesive can be an alternative method for combining the bond performance and therapeutic effects. The use of an adhesive with up to 5% nanocapsules containing indomethacin and triclosan and a primer with no nanocapsules maintained the long-term bond performance