Do the new, modern dental resin composites improve the sealing in cavities restorations? The present study was designed to compare the effect of two different, but most used layering techniques of the dental composite in reducing the marginal microleakage when a brand-new material is used; Class I black cavities were prepared on 120 human extracted teeth and then restored using oblique and horizontal layering technique. The dye penetration analysis, the atomic force microscopy (AFM), scanning electron microscopy (SEM) together with energy-dispersive X-ray spectroscopy (EDX) and Fourier transform infra-red spectroscopy (FTIR) technique were used to assess the adaptation of the restorative material to the dental structures. Some better results were obtained for oblique layering technique, but the differences to the other method have not been statistically validated. The composite layering technique still remains an open quest and, moreover, in vivo studies should be designed in order to assess microleakage in real conditions of the oral environment.

(1) Background: Which are the adhesion characteristics of four root canal sealers: two experimental (dual cure resin based endodontic sealer (E1-DCR) and bioceramic based sealer (E2-BC)), and two commercial (RealSeal and TotallFill BC (FKG Germany)). (2) Methods. One-hundred-twenty extracted monoradicular teeth received mechanic-antiseptic preparation and then endodontic filling using gutta-percha in combination with one of the four sealers. Samples from the apical third were selected from each tooth and were randomly distributed for Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM) and push-out bond strength. Fourier Transform Infrared (FTIR) Spectroscopy was made exclusively for experimental sealers. (3) Results. The two experimental materials did not present a significant difference in apical sealing ability based on SEM evaluation. Gaps were identified in case of RealSeal samples and also lower penetration into the dentinal tubules compared to TotalFill BC. On AFM analysis a more pronounced penetration into the tubules was observed in case of E2-BC sealer was observed. E1-DCR registered a lower bond strength (0.7177 ± 0.55) in the apical third compared to Total Fill BC (p = 0.01). (4) Conclusions. Within the limitations of the current study, it can be stated that the two experimental sealers’ characteristics are comparable to that of the two consecrated materials.

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ABSTRACT. Direct bonding of the bracket to the enamel is the elective procedure for the orthodontic treatment. Among various factors influencing the adhesive force at the enamel level, the etching technique seems to be the most important one. The present study aims at evaluating the influence of the storage media and the etching technique used, on the bond strength between different bracket types and dental structures. The results of this study showed that, regardless of the brackets and the immesion solution used, by working with the classic etch and rinse technique the adhesion force is higher than by using a self etching adhesive.

Orthodontic adhesives have similar properties in terms of fluoride release, roughness, shear bond strength or cement debris for specific clinical conditions. Three commercial consecrated orthodontic adhesives (Opal Seal®, Blugloo®, Light Bond®) were compared with an experimental orthodontic material (C1). Brackets were bonded to enamel using a self-etch technique followed by adhesive application and then de-bonded 60 days later. Share bond strength evaluation, scanning electron microscopy, atomic force microscopy and fluoride release analysis were performed. The highest amount of daily and cumulative fluoride release was obtained for the experimental material, while the lowest value was observed for Opal Seal®. The materials evaluated in the current study presented adequate shear bond strength, with the experimental material having a mean value higher than Opal Seal and Blugloo. The atomic force microscopy measurements indicated that the smoothest initial sample is Opal Seal® followed by Light Bond®. Scanning electron microscopy evaluation indicated different aspects of cement debris on the enamel and/or bracket surface, according to the type of adhesive. The experimental material C1 presented adequate properties in terms of shear bond strength, fluoride release, roughness and enamel characteristics after de-bonding, compared to the commercial materials. Under these circumstances, it can be considered for clinical testing.