Results suggest that the sonic insertion method might increase void formation during resin composite delivery, depending on restorative material brand.

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This study evaluated the influence of different light-curing modes on the volumetric polymerization shrinkage and degree of conversion of a composite resin at different locations using micro-computed tomography and Fourier transform infrared spectroscopy (FTIR). Specimens were divided into 4 groups based on the light-curing mode used (Bluephase 20i): 1 -High (1,200 mW/cm 2 ); 2 -Low (650 mW/cm 2 ); 3 -Soft-start (650-1,200 mW/cm 2 ); and 4 -Turbo (2,000 mW/cm 2 ). Degree of conversion was calculated by the measurement of the peak absorbance height of the uncured and cured materials at the specific wavenumbers, and was performed by FTIR 48 h after curing resin samples. Degree of conversion was analyzed using two-way ANOVA. No significant differences were observed independent of the region of the restoration investigated (p>0.05). Different curing modes did not influence volumetric shrinkage neither degree of conversion of class I composite resin restorations.

The study evaluated the effects of a Supercritical CO (scCO ) on a commercially available decellularized/delipidized naturally derived porcine pericardium collagen membrane, Vitala®. The Vitala® and scCO treated experimental membranes were evaluated for guided tissue regeneration (GTR) of periodontal tissue in class III furcation defects utilizing a dog model. Physical material characterization was performed by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). The in vivo portion of the study was allocated to three-time points (6, 12, and 24-weeks) using standardized class III furcation defects created in the upper second and third premolars. The experimental defects (n = 5) were covered with either a collagen membrane (positive control), scCO -treated collagen membrane (experimental) or no membrane (negative control). Following sacrifice, histologic serial sections were performed from cervical to apical for morphologic/morphometric evaluation. Morphometric evaluation was carried out by ranking the presence of collagen membrane, amount of bone formation within the defect site and inflammatory cell infiltrate content. SEM showed the experimental scCO -treated membrane to have a similar gross fibrous appearance and chemical structure in comparison to the Vitala® Collagen membrane. A significant increase in membrane thickness was noted in the scCO -treated membranes (366 ± 54 μm) vs non-treated membranes (265 ± 75 μm). TGA and DSC spectra indicated no significant qualitative differences between the two membranes. For the in vivo results, both membranes indicated significantly greater amounts of newly formed bone (scCO : 2.85 ± 1.1; Vitala®: 2.80 ± 1.0) within the covered defects relative to uncovered controls (0.8 ± 0.27) at 24 weeks. Both membrane types gradually degraded as time elapsed in vivo from 6 to 12 weeks, and presented nearly complete resorption at 24 weeks. The inflammatory infiltrate at regions in proximity with the membranes was commensurate with healthy tissue levels from 6 weeks in vivo on, and periodontal ligament regeneration onset was detected at 12 weeks in vivo. The effect of the supplementary scCO treatment step on the collagen membrane was demonstrated to be biocompatible, allowing for the infiltration of cells and degradation over time. The treated membranes presented similar performance in GTR to non-treated samples in Class III furcation lesions. Defects treated without membranes failed to achieve regeneration of the native periodontium. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res B Part B: Appl Biomater 00B: 000-000, 2018.

The understanding of cuspal deflection and volumetric shrinkage of resin composites is necessary to assess and improve the placement techniques of resin-based materials. The aim of this study was to investigate the cuspal deflection and its relationship with volumetric polymerization shrinkage of different bulk-fill resin composites. The investigation was conducted using non-contact phase microscopy and micro-computed tomography. Thirty custom-milled aluminum blocks were fabricated for microscopy analysis and thirty-six tooth models with standardized Class I cavities were used for micro-computed tomography analysis. Results showed that high-viscosity composites present higher cuspal deflection compared to bulk-fill composites. The filler loading of resin composites seems to have an effect on cusp deflection, since the higher the filler content percentage, the higher the cusp deflection. On the other hand, it seems to have an opposite effect on volumetric shrinkage, since higher filler loadings produced lower volumetric shrinkage percentages.

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