The effects of in-office reconditioning on the morphology of slots and bases of stainless steel brackets and on the shear/peel bond strength

Abstract

Objectives: To compare the effect of five in-office bracket reconditioning methods on: (i) bracket slot width and interwing gap measurements; (ii) the appearance of the bracket bases under scanning electron microscope (SEM), and; (iii) shear/peel bond strength (SPBS).

Setting: Ex vivo study.

Method: One hundred and twenty-five brackets were initially bonded and were divided into five experimental groups and reconditioning by the following methods: (i) adhesive grinding using green stone (Gp II); (ii) sandblasting (Gp III); (iii) direct flaming (Gp IV); (iv) using the BigJane machine (Gp V), and; (v) application of Buchman method (Gp VI).

Outcomes: Distortion of the brackets. Scanning electron microscopy of three representative specimens from each group. The remaining brackets were rebonded, then shear/peel forces to failure were measured (SPBS).

Results: The ANOVA and multiple comparison test exhibited a statistical, but not clinical, significant increase in the bracket measurements of Group VI. There was a significant reduction (28%) in the SPBS of Group II. Under the SEM, the wire mesh structure was maintained; however, the amount of adhesive remnants greatly varied among the groups.

Conclusions: Although none of the in-office reconditioning methods employed adversely affected the bracket base and/or the bracket measurements, reconditioning with a green stone was not effective. Sandblasting method and direct flaming are recommended because of simplicity and time-saving advantages.