In vitro evaluation of microleakage under orthodontic brackets bonded with different adhesive systems.

OBJECTIVE: Adhesives systems have a drawback when utilized for bonding orthodontic brackets: they shrink during photopolymerization creating microleakage. The aim of this study was to assess the stability of different orthodontic adhesives around brackets and enamel. MATERIALS AND METHODS: Sixty noncarious mandibular premolars extracted for orthodontic reasons were randomly divided into six groups of adhesives used for bonding brackets to dental enamel: NeoBond® Light Cure Adhesive Kit, Transbond™ Plus Self-Etching, Victory V-Slot APC PLUS® + Transbond™ MIP, Rely-A-Bond® Kit, Light Cure Orthodontic Adhesive Kit (OptiBond®), and Transbond™ MIP. Following bonding, all teeth underwent 2500 cycles of thermal cycling in baths ranging from 5°C to 55°C before being immersed in 2% methylene blue for 24 h. All samples were examined under a binocular microscope to assess the degree of microleakage at the "bracket-adhesive" and "adhesive-enamel" interfaces in the gingival and occlusal regions of the bracket. RESULTS: A significant difference was found at the "occlusal bracket-adhesive" interface. The highest microleakage values were found in the occlusal region, although no significant. Microleakage was observed in all groups. CONCLUSION: Group 2 had the highest microleakage values whereas Group 6 had the lowest values.

Impact of dental and skeletal movements on the facial profile within the framework of orthodontic and surgical treatments.

The impact of dental and skeletal movements on the soft tissues during orthodontic and surgical treatments is widely known. Most studies are limited to examining the repercussions of a dental or skeletal movement on a given soft tissue point. The uniqueness of the present study, carried out on 95 patients, lies in the examination of the impact of movements of various landmarks--2 dental points (incision superius and incision inferius) and 4 skeletal points (anterior nasal spine, point A, point B, andpogonion)--on 7 soft tissue landmarks (from the tip of the nose to soft tissue pogonion). The study was carried out with the purpose of providing a simple, practical, and accurate tool for clinical use to assist in treatment planning. This article outlines the main aspects of the tool while specifying its limitations and error margins.