COMPARISON OF DIFFERENT BRACKET RECYCLING METHODS ON SHEAR BOND STRENGTH

Abstract

Background: Choosing what to do with debonded or incorrectly positioned brackets is a regular dilemma for orthodontists. Recycling the brackets is a cost-effective solution to this problem. Although numerous recycling techniques have been put forth, more research is necessary to determine the ideal bond strength of these recovered brackets. Objectives: To evaluate and compare the effect of six recycling methods: (i) Direct flaming (ii) Greenstone Bur (iii) Acid bath solution (iv)Sandblasting(v) Butchman Method (vi) Ultrasonic on shear bond strength (SBS) of stainless steel brackets. Material and Methods: One hundred eighty human premolars were bonded with premolar stainless steel brackets as per manufacturer’s instructions. The teeth were divided into 6 groups (n=30): After initial bonding, the brackets in the six experimental groups were debonded and recycled by following methods:(i) Direct flaming (ii) Greenstone Bur (iii) Acid bath solution (iv)Sandblasting(v) Butchman Method (vi) Ultrasonic . Further the recycled brackets were bonded. The specimens were then subjected to testing in a Universal machine. The evaluation of the variation of the shear bond strength (SBS) among test groups was done using one-way ANOVA test and followed by post hoc multiple comparison test. Results: the mean shear bond strength for each group is presented. After sandblasting (7.26 ± 0.20 MPa), the Butchman recycling method (8.45 ± 0.29 MPa) offered the highest bond strength. The methods that provided the lowest shear bond strength were acid etch (4.22 ± 0.21 MPa) and ultrasonic (4.59 ± 0.18 MPa). Statistically significant variations existed in the shear bond strength (SBS) in all groups analyzed. Conclusions: T Shear bond strength of recycled brackets by Butchman’s Method is significantly higher than the other five methods. Brackets recycled with flame method and brackets sandblasted with 50μm aluminium oxide particle air-abrasion showed significantly shear bond strength which is clinically acceptable to be used as resuable brackets. Brackets recycled with, acid bath, ultrasonic and greenstone bur showd clincically insigificant result to be used after recycling.