Microleakage beneath Ceramic and Metal Brackets Bonded with a Conventional and an Antibacterial Adhesive System

Abstract

Objective: To assess microleakage of a tooth-adhesive-bracket complex when metal or ceramic brackets were bonded with a conventional and an antibacterial self-etching adhesive. Materials and Methods: Forty freshly extracted human premolars were randomly assigned to four equal groups and received the following treatments: group 1 = Transbond XT + metal bracket, group 2 = Transbond XT + ceramic bracket, group 3 = Clearfil Protect Bond + ceramic bracket, and group 4 = Clearfil Protect Bond + metal bracket. After photopolymerization, the teeth were kept in distilled water for 1 month and thereafter subjected to thermal cycling (500 cycles). Specimens were further sealed with nail varnish, stained with 0.5% basic fuchsin for 24 hours, sectioned and examined under a stereomicroscope, and scored for marginal microleakage for the adhesive-tooth and bracket-adhesive interfaces from incisal and gingival margins. Statistical analysis was accomplished by Kruskal-Wallis test and Mann-Whitney U-test with Bonferroni correction. Results: All groups demonstrated microleakage between the adhesive-enamel and bracket-adhesive interfaces. A significant difference was observed among all groups (P < .05) for the microleakage between the bracket-adhesive interface. Metal brackets exhibited significantly more microleakage than did ceramic brackets between the bracket-adhesive interface with either of the adhesives. Clearfil Protect Bond exhibited results similar to Transbond XT. Clearfil Protect Bond may be a choice of adhesive in bracket bonding because of its antibacterial activity and similar microleakage results with the orthodontic adhesive. Conclusions: Metal brackets cause more leakage between an adhesive-bracket interface, which may lead to lower clinical shear bond strength and white-spot lesions.

Microleakage under Metallic and Ceramic Brackets Bonded with Orthodontic Self-Etching Primer Systems

“…Arhun et al 8 found that microleakage scores obtained from the incisal and gingival margins of the brackets demonstrated significant differences, implying increased microleakage on the gingival side. They interpreted these differences as related to the surface curvature anatomy, which may result in relatively thicker adhesive at the gingival margin.…”

“…11 However, from an orthodontic perspective this condition is different. Adhesives at the edges of the bracket can absorb some shrinkage, 8 and this shrinkage can pull the bracket closer to the enamel by the free floating of the bracket. In contrast to the thick composite resin put in a prepared cavity in restorative dentistry, polymerization shrinkage and the subsequent microleakage is less of a concern in orthodontic adhesives because a thin layer is used.…”

“…After being removed from the solution, the teeth were rinsed in tap water, and the superficial dye was removed with a brush and dried. Four parallel longitudinal sections were made through the occlusal and gingival surfaces with a low-speed diamond saw (Isomet, Buehler, Lake Bluff, Ill) in the bucco-lingual direction according to Arhun et al 8 Each section was scored from both occlusal and gingival margins to the brackets between both the enamel-adhesive and the adhesive-bracket interface. Microleakage was determined by direct measurement using an electronic digital caliper, and data were recorded to the nearest value as a range 0.5-5 mm.…”

“…3,4 Although tooth-conserving and time-saving adhesive methods of retaining orthodontic attachments are replacing traditional methods and procedures, a significant caries risk under and in the vicinity of the multibonded appliances is of concern. 6,7 According to Arhun et al, 8 investigators in the literature 9,10 were interested in decalcifications and white spots around the brackets, not under the brackets, and they pointed out that although the area around the brackets is critical, the area under the brackets also needs attention.…”

“…In the orthodontic literature, James et al 11 noted the increased risk of decalcification caused by microleakage around orthodontic brackets. Then Arhun et al 8 assessed microleakage of a tooth-adhesive-bracket complex when metal or ceramic brackets were bonded with a conventional and an antibacterial adhesive. They found that metal brackets caused more leakage between the adhesive-bracket interface, which may lead to lower clinical shear bond strength and whitespot lesions.…”