Orthodontic bonding with self-etching primer and self-adhesive systems.

The purpose of this study was to compare the tensile bond strengths of orthodontic brackets bonded to enamel using conventional multi-step adhesive, self-etching primer (SEP), which combines etching and priming into a single step, and self-adhesive systems, which combine etchant, primer, and adhesive. Metal brackets were bonded to 90 extracted human premolars according to three experimental protocols: group 1, conventional multi-step adhesive system; group 2, SEP; and group 3, self-adhesive system. All specimens were debonded using an Instron universal machine and failures between the tooth surface and bracket base were observed by scanning electron microscopy (SEM). The bracket bases were then analysed by mapping of energy-dispersive X-ray (EDX) spectrometry to calculate the distributive percentages of enamel or resin. The bond strength, percentage distribution, and calcium on the debonded interface were determined and analysed by one-way analysis of variance, and means were ranked by a Tukey interval, calculated at the 95 per cent confidence level. Group 1 produced the greatest bond strength, followed by groups 2 and 3. Group 3 showed the highest debonded interface between resin and enamel or within the resin itself, followed by groups 2 and 1. Groups 1 and 2 displayed significantly more debond failures at the interface between the bracket and the resin than group 3. More calcium particles were observed on the bracket base after debonding in group 3 than in groups 2 and 1. The simplified bonding procedures caused an undesirable decrease in tensile bond strength.

Biological surface modification of titanium surfaces using glow discharge plasma.

To improve the biological activity of titanium, by using of glow discharge plasma (GDP), albumin-grafted titanium disk have been implemented and carefully studied. Titanium disks were pre-treated with GDP in an environment filled with argon and allylamine gas. Glutaraldehyde was used as a cross-linking agent for albumin grafting. Then, the surface of the albumin-grafted titanium was examined using scanning electron microscopy and X-ray photoelectron spectroscopy. In addition, the static water contact angles of the albumin-grafted titanium disks were measured using goniometry. To observe the effects of albumin adsorption on cell behavior, MG-63 osteoblast-like cells were cultured on the surface-modified titanium disks. Blood coagulation resistance of the modified titanium was monitored and compared to the control titanium disks. The results demonstrated that MG-63 osteoblast-like cells cultured on the albumin-grafted titanium disks expressed better-differentiated morphology compare to cells grown on the control disks. Furthermore, albumin-grafting treatment significantly improved the surface wettability of the titanium disks and resulted in a significantly negative effect on thrombus formation. Based on these results, it was believed that the GDP can potentially improve the biofunctionality of titanium surfaces.