Objectives. e aim of this study was to evaluate the shear bond strength of metal brackets bonded with different universal adhesive systems containing 10-MDP and Transbond Plus Self Etching Primer after 20,000 thermal cycles. Materials and Methods. A total of 130 sound bovine teeth were used, which are divided into 5 groups (n = 26) according to the adhesive system used: All-Bond Universal (Bisco), Ambar Universal (FGM), Clearfil Universal Bond (Kuraray), Single Bond Universal (3M/ESPE), and Transbond Plus SEP (3M/ESPE) as control. e adhesives were applied for 20 seconds and bonded with a resin Transbond XT (3M/ESPE). After this, the teeth were submitted to 20,000 cycles at 5°C and 55°C. Afterwards, the shear bond strength test was performed in a universal test machine (Instron 3342). e adhesive remnant index (ARI) was evaluated under a stereomicroscope at 10x magnification and scanning electronic microscopy (SEM, Hitachi 3030). e shear bond strength data were submitted to One-Way ANOVA (α = 0.05) and the ARI to the Kruskal-Wallis test (α = 0.05). Results. Statistical analysis showed that the universal adhesive systems presented mean shear bond strength values similar to Transbond Plus SEP (p < 0.05). e universal adhesive presented similar ARI values among them but differed from those of Transbond Plus SEP (p < 0.001). Transbond Plus SEP presented a high ARI value when compared with the universal adhesive systems and high demineralization of enamel.Conclusions. e results show that universal adhesive systems may be used for bonding metal brackets if the orthodontist wants to maintain dental enamel health.

The advantage of using an Enamel matrix derivative EMD Emdogain as an intracanal medication could be a manner to strength the tooth structure, improving the physical and chemical properties of dentin. We tested, in vitro, the effect of Emdogain on the surface microhardness and chemical composition of root dentin. Ten human teeth were used to produce dentin specimens originated from the canal walls (n = 30) that remained in contact to Emdogain gel for 90 days. Baseline and 90-days after Emdogain treatment measurements were performed using Fourier Transform Infrared Spectroscopy (ATR/FTIR), Scanning Electron Microscopy/Energy Dispersive Spectroscopy (SEM/EDS) and Knoop indenters. The use of EMD (Emdogain) for 90 days in contact with human root canal dentin specimens did not alter the microhardness and morphology of dentin. The elemental structure of dentin was altered because there was a reduction in carbonate content.