Effect of orthodontic debonding and residual adhesive removal on 3D enamel microroughness

Abstract

BackgroundTermination of fixed orthodontic treatment is associated with bracket debonding and residual adhesive removal. These procedures increase enamel roughness to a degree that should depend on the tool used. Enamel roughening may be associated with bacterial retention and staining. However, a very limited data exists on the alteration of 3D enamel roughness resulting from the use of different tools for orthodontic clean-up.Aims1. To perform a precise assessment of 3D enamel surface roughness resulting from residual adhesive removal following orthodontic debonding molar tubes.2. To compare enamel surfaces resulting from the use of tungsten carbide bur, a one-step polisher and finisher and Adhesive Residue Remover.Material and MethodsBuccal surfaces of forty-five extracted human third molars were analysed using a confocal laser microscope at the magnification of 1080× and 3D roughness parameters were calculated. After 20 s etching, molar tubes were bonded, the teeth were stored in 0.9% saline solution for 24 hours and debonded. Residual adhesive was removed using in fifteen specimen each: a twelve-fluted tungsten carbide bur, a one-step finisher and polisher and Adhesive Residue Remover. Then, surface roughness analysis was repeated. Data normality was assessed using Shapiro–Wilk test. Analysis of variance (ANOVA) was used to compare between variables of normal distribution and for the latter—Kruskal-Wallis test.ResultsSa (arithmetical mean height) was significantly different between the groups (p = 0, 01326); the smoothest and most repeatable surfaces were achieved using Adhesive Residue Remover. Similarly, Sq (root mean square height of the scale-limited surface) had the lowest and most homogenous values for Adhesive Residue Remover (p = 0, 01108). Sz (maximum height of the scale-limited surface) was statistically different between the groups (p = 0, 0327), however no statistically significant differences were found concerning Ssk (skewness of the scale-limited surface).DiscussionConfocal laser microscopy allowed 3D surface analysis of enamel surface, avoiding the limitations of contact profilometry. Tungsten carbide burs are the most popular adhesive removing tools, however, the results of the present study indicate, that a one step polisher and finisher as well as Adhesive Residue Remover are less detrimental to the enamel. This is in agreement with a recent study based on direct 3D scanning enamel surface. It proved, that a one-step finisher and polisher as well as Adhesive Residue Remover are characterized by a similar effectiveness in removing residual remnants as tungsten carbide bur, but they remove significantly less enamel.ConclusionOrthodontic debonding and removal of adhesive remnants increases enamel roughness. The smoothest surfaces were achieved using Adhesive Residue Remover, and the roughest using tungsten carbide bur.

Evaluation of a Fluorescence-aided Identification Technique (FIT) to assist clean-up after orthodontic bracket debonding

“…This can lead to an increased enamel loss of up to 60 lm with a tungsten carbide bur. 6 Enamel scratches should be avoided as much as possible 26 since they enhance bacterial adhesion 5 and cannot be eliminated by polishing. 27,28 These enamel alterations of bracket debonding and adhesive removal affect the optical properties of the enamel surface.…”

Effects of different primers on indirect orthodontic bonding: Shear bond strength, color change, and enamel roughness

“…There are studies that have used confocal microscopy and atomic force microscopy, which analyze a smaller area than that assessed in the present study. 25 26 …”

In vitro bond strengths post thermal and fatigue load cycling of sapphire brackets bonded with self-etch primer and evaluation of enamel damage

“…While this finding is in agreement with the fact that the 37% PA etchant yields the highest bond strengths in comparison to any other etchant, this unnecessarily excessive bond strength has been a point of contention as it is frequently accompanied by varying forms of enamel damage (8,24). In addition, since the debonding inevitably leaves adhesive remnants on the enamel surface, enamel clean-up and polishing is required to remove these remnants (usually using rotary burs) resulting in increased chair-side time and enamel scratching (3,7). On the other hand, although enamel etching with SEP exhibited lower SBS (15.1-22.4 MPa) than the PA gel (23.4-29.8 MPa) at both bracket debonding time points, the values obtained were well above the minimum requirement for clinical performance (6-10 MPa).…”

“…Research has shown that an etch-and-rinse (EaR) approach using phosphoric acid remains the preferred choice for enamel conditioning in orthodontics since it guarantees a durable bracket bond to enamel (1,2). However, high shear bond strength (SBS) values have been accompanied by more adhesive residues with iatrogenic enamel fracture, chipping, or cracking due to the higher debonding force required to remove the brackets after treatment (3). Attempts to employ various concentrations of other acids such as pyruvic, lactic, nitric, maleic, tannic and citric acids resulted in suboptimal bond strengths not suitable for clinical performance and failed to outperform the etching ability of phosphoric acid (4).…”