Evaluation of enamel roughness after orthodontic debonding and clean-up procedures using zirconia, tungsten carbide, and white stone burs: an in vitro study

Abstract

Background The main goal of orthodontic debonding is to restore the enamel surface as closely as possible to its pretreatment condition without iatrogenic damage. This study aimed to compare the effects of different adhesive removal burs; zirconia burs, tungsten carbide burs, and white stone burs on enamel surface roughness. Materials and methods Total sample of 72 extracted premolars was randomly divided into three equal groups (n = 24) depending on the method of adhesive removal: zirconia burs (ZB); tungsten carbide burs (TC); and white stones (WS). The metal brackets were bonded using Transbond XT orthodontic adhesive (3 M Unitek, Monrovia, CA, USA) and debonded after 24 h using a debonding plier, then the ARI was assessed. The adhesive remnants were removed using the different burs and Final polishing was performed using Sof-lex discs and spirals. Thirteen samples from each group were evaluated using a Mitutoyo SJ-210 profilometer to determine average surface roughness (Ra) and three samples from each group were examined under Scanning Electron Microscopy (SEM) to determine EDI score. The evaluations were performed at three time points; before bonding (T0), after adhesive removal (T1) and after polishing (T2) and the time consumed for adhesive removal by burs was recorded in seconds. The data were analyzed statistically by ANOVA, Tukey’s test and Kruskal–Wallis H-test. Results Kruskal–Wallis H-test showed no statistically significant difference of ARI in all studied groups (p = 0.845) and two-way mixed ANOVA revealed that all burs significantly increased surface roughness at T1 compared to T0 (p < 0.001) in all groups with the lowest Ra values were observed in the ZB group, followed by the TC group, and WS group. The fastest procedure was performed with WS, followed by ZB, then TC bur (p < 0.001). After polishing (T2), Ra values showed no significant difference in ZB group (P = 0.428) and TC group (P = 1.000) as compared to T0, while it was significant in WS group (p < 0.001). Conclusion zirconia bur was comparable to tungsten carbide bur and can be considered as alternative to white stone which caused severe enamel damage. The polishing step created smoother surface regardless of the bur used for resin removal.

Comparison of Enamel Surface Integrity after De-Bracketing as Affected by Seven Different Orthodontic Residual Cement Removal Systems

“…Similar results were reported by other studies [27,28]. Various studies have reported different degrees of enamel loss during the removal of residual adhesive material, ranging from a few micrometers to around 50 µm [28][29][30][31]. Enamel thickness is stated to range from 1500 µm to 2000 µm; accordingly, it was reported that enamel loss of around 60 µm is not considered detrimental to the tooth [32].…”

Evaluation of enamel surface integrity after orthodontic bracket debonding: comparison of three different system

“…Similar to our results, Tenório et al[ 33 ] Shafiee et al[ 34 ], and Ulusoy [ 23 ] showed that the time spent for resin removal with the TC bur was shorter than polymer bur and white stones, respectively. On the other hand, Thawaba et al [ 15 ] reported that. Zirconia burs were more effective for adhesive resin removal than TC systems, causing the least surface roughness and enamel damage.…”

“…The sample size was calculated using G* Power software (v3.1.3; Franz Faul, Universität Kiel, Germany) which depends on the effect size = 0.80, an alpha value of 0.05, and a power of 95%. The result showed that at least 15 samples were required in each group based on the study conducted by Thawaba et al [ 15 ]. However, the sample size was raised to 20 samples for each study group.…”