This study evaluated the influence of thermo-mechanical cycling (TMC) on the bond strength (BS) of a universal adhesive system (UAS -Adper Single Bond Universal, 3M ESPE) to dentin treated or not with 0.2% chlorhexidine (CHX). Methods: Eighty human molars were flattened until reach the dentin and separated into 4 groups according to the bonding protocol: ENR Group: 37% phosphoric acid þ 3-step etch-and-rinse adhesive system (ENR); UAS Group:After treatments, teeth were restored (Filtek Z350, 3M ESPE). Samples (n ¼ 10) were submitted to aging process: stored in distilled water at 37 C/30 days or TMC (ERIOS -98N/1.6Hz þ thermal cycling 5/37/ 55 C -1,200,000 cycles). Specimens were sectioned into sticks (1.0 mm 2 ) and submitted to the microtensile test (Mechanical Test Machine -0.5 mm/min). Fracture patterns and hybrid layer integrity were analyzed under Stereomicroscope and Scanning Electron Microscopy (SEM). Results:The BS results (3-way ANOVA, Bonferroni's test, α ¼ 5%) showed that groups treated with CHX presented higher BS values than control groups; significant in all cases (p < .05), except for ENR submitted to TMC (p > .05). When CHX was applied and samples were cycled, UAS revealed higher BS (p < .05) than ENR. After TMC, cohesive fractures increased for UAS, regardless of CHX application. SEM analysis demonstrated different hybridization patterns for the adhesive systems tested. Conclusion:The performance of the universal adhesive system used in self-etch mode was better than that of the 3step etch-and-rinse adhesive system. Clinical significance: Universal adhesive systems have been developed in order to simplify the dentin hybridization protocol. It is important to determine the longevity of the adhesive interface using these bonding materials after chewing.

Turkish Journal of Orthodontics (Turk J Orthod) is an international, scientific, open access periodical published in accordance with independent, unbiased, and double-blinded peer-review principles. The journal is the official publication of Turkish Orthodontic Society and it is published quarterly on March, June, September and December. Turkish Journal of Orthodontics publishes clinical and experimental studies on on all aspects of orthodontics including craniofacial development and growth, reviews on current topics, case reports, editorial comments and letters to the editor that are prepared in accordance with the ethical guidelines. The journal's publication language is English and the Editorial Board encourages submissions from international authors.

No abstract

Background: Fatal accidents involving the action of heat, such as burns, explosions, automobile accidents, and aircraft crashes, among others, or action of cold, such as collisions in snowy locations, severe blizzards, cold waves, earthquakes, and avalanches, are frequent day-to-day occurrences. During post-mortem dental examination of victims, restorative materials such as the composite resin (CR), glass ionomer cement (GIC), and amalgam may be found. The action of the heat or cold on these materials may change their properties. This study aimed to evaluate the changes occurred in the surface roughness and Knoop microhardness of the dental restorative materials of freezing or burnt victims, supporting an adequate comparison with the antemortem data, helping on human identification process. Methods: One hundred eighty caries-free bovine teeth were prepared and separated into groups, according to the restorative material, temperature, and period for analysis. The surface roughness and microhardness were analyzed by a profilometer and a microhardness tester, before and after the action of the heat (100°C, 200°C, 300°C) and the cold temperatures (2.5°C, − 20°C, − 80°C). Results: The results demonstrated that there was no alteration on properties of CR after the heat that caused significant changes in the surface roughness of GIC and amalgam and the microhardness of GIC. The low temperatures produced no significant differences in any of the properties of the restorative materials studied. Conclusion: The surface roughness and Knoop microhardness tests could distinguish the tooth-colored restorative materials irrespective of the action of the heat or cold temperatures.

No abstract