# Orthodontic Bracket Removal and Enamel Roughness: Comparing the Effects of Sapphire and Metallic Brackets in an In Vitro Study

## TL;DR

This study compares how removing sapphire and metallic orthodontic brackets affects enamel roughness and finds that sapphire brackets cause more roughness.

## Contribution

The study introduces a direct comparison of enamel roughness caused by sapphire versus metallic brackets and evaluates the effectiveness of remineralization.

## Key findings

- Sapphire brackets caused significantly higher enamel roughness (4.14 ± 0.36 µm) compared to metallic brackets (2.56 ± 0.52 µm) after debonding.
- Remineralization reduced roughness in both groups but did not restore it to baseline levels.
- Enamel roughness remained above the clinical threshold for plaque retention in both groups after remineralization.

## Abstract

Background: Enamel surface roughness after bracket debonding is an important issue due to its impact on plaque accumulation and the potential development of carious lesions. This in vitro study aimed to assess enamel roughness after the removal of metallic and sapphire brackets and the effect of a remineralization treatment. Methods: Two hundred extracted human permanent teeth with healthy enamel were randomly distributed into two groups (n = 100) and bonded with either metallic or sapphire brackets using the same adhesive (3M™ Transbond™ XT (St. Paul, MN, USA), Minnesota Mining and Manufacturing Company, MN, USA). The enamel surface roughness was measured before bonding, after debonding, and after remineralization using SEM and a TR200 roughness (SaluTron GmbH, Frechen, Germany) tester. The parameter Ra was used to quantify the surface roughness. One-way ANOVA, the normality test, variance homogeneity, and the Bonferroni post hoc test were used to analyze the data. Results: Debonding significantly increased the enamel surface roughness in both groups. The sapphire bracket group presented significantly higher mean Ra values post debonding (4.14 ± 0.36 µm) compared to the metallic group (2.56 ± 0.52 µm). Remineralization led to a decrease in surface roughness in both groups, though not to baseline levels. The changes were statistically significant (p < 0.01), with a power of the test of 1.0. Conclusions: The bracket material significantly affects enamel surface roughness after orthodontic debonding. Sapphire brackets produced greater surface irregularities than metallic ones. Remineralization partially reduced roughness in both groups, with the final values in the metallic group being closer to baseline levels. Crucially, these values remained far above the clinical threshold for plaque retention, highlighting the need for improved debonding techniques.