Shear bond strength of new and recycled brackets to enamel

Abstract

The purpose of this study was to evaluate in vitro the shear bond strength of recycled orthodontic brackets. S2C-03Z brackets (Dental Morelli, Brazil) were bonded to the buccal surfaces of 50 extracted human premolars using Concise Orthodontic chemically cured composite resin (3M, USA). The teeth were randomly assigned to 5 groups (n=10), as follows. In group I (control), the bonded brackets remained attached until shear testing (i.e., no debonding/rebonding). In groups II, III and IV, the bonded brackets were detached and rebonded after recycling by 90-μm particle aluminum oxide blasting, silicon carbide stone grinding or an industrial process at a specialized contractor company (Abzil-Lancer, Brazil), respectively. In group V, the bonded brackets were removed and new brackets were bonded to the enamel surface. Shear bond strength was tested in an Instron machine at a crosshead speed of 0.5 mm/min. Data were analyzed statistically by ANOVA and Tukey's test at 5% significance level. There was no statistically significant difference (p>0.05) between the control brackets (0.52 kgf/mm 2 ), brackets recycled by aluminum oxide blasting (0.34 kgf/mm 2 ) and new brackets attached to previously bonded teeth (0.43 kgf/mm 2 ). Brackets recycled by the specialized company (0.28 kgf/mm 2 ) and those recycled by silicon carbide stone grinding (0.14 kgf/mm 2 ) showed the lowest shear strength means and differed statistically from control brackets (0.52 kgf/ mm 2 ) (p<0.05). In conclusion, the outcomes of this study showed that bracket recycling using 90-μm aluminum oxide particle airabrasion was efficient and technically simple, and might provide cost reduction for orthodontists and patients alike.

Reconditioning of self-ligating brackets

“…These problems cause disturbances, delay the treatment, and increase costs. 1 Once detached, a bracket can be replaced with a new or reconditioned one during rebonding. The reconditioning process basically consists of removing the bonding agent remnants from the bracket base, thus allowing the brackets to be reused without causing damage to the retention mesh while preserving its retentive characteristics.…”

“…Therefore, it might be useful if the orthodontist could manage the in-office reconditioning processes without affecting the shear bond strength (SBS) of these brackets. To date the literature contains many published articles 1,10,11 that involved testing the SBS of new vs reconditioned brackets, but there are no studies that have involved evaluation of the effect of the reconditioning process on the SBS of the newgeneration self-ligating orthodontic brackets.…”

Comparative Study of Shear Bond Strength of Recycled Brackets using different Recycling Techniques – An in vitro study

“…Recycling consist of the removal of remnant bonding agent on the bracket bases, without causing damage to the retention mesh and preserving retentive characterstics. 6 Several techniques are available for recycling brackets. On the other hand, sandblasting with aluminum oxide particles (90 micron) for 15-30 seconds at a distance of 10 mm from the bracket bases is efficient and technically simple, as reported by Tavares et al 6 It also enhance bracket bonding to tooth structure by producing micromechanical retention on base surface due to the increase in the area of composite interlocking, which is essentially mechanical due to the microasperity of the bracket mesh.…”

“…6 Several techniques are available for recycling brackets. On the other hand, sandblasting with aluminum oxide particles (90 micron) for 15-30 seconds at a distance of 10 mm from the bracket bases is efficient and technically simple, as reported by Tavares et al 6 It also enhance bracket bonding to tooth structure by producing micromechanical retention on base surface due to the increase in the area of composite interlocking, which is essentially mechanical due to the microasperity of the bracket mesh. These reasons positively guided us to choose sandblasting with aluminium oxide to be the method of choice for recycling in the present study.…”

Comparison of Two Different Orthodontic Bracket Recycling Techniques

“…According to Tavares et al, 8 the methods of recycling brackets may be classified as Industrial (chemical and heating) and chair-side use of a tungsten carbide bur, heating and sandblasting.…”