Eising, M. (Marloes) (2009) Qualitative Analysis of the morphological aspects of enamel surface; comparing two different finishing methods after debonding. thesis, Dentistry.
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Abstract
Introduction: Debonding of orthodontic brackets is an inevitable step when using fixed appliances. In the past, different kinds of etching, bonding, bracket removal methods and fmishing procedures have been tested to find the most effective, but safe working method. Every method which is effective in the removal of adhesive resin, introduces some form of abrasion. This depends on the size and composition of the abrasive particles. The tungsten carbide bur is most often used for the removal of the resin, at high or low speed. There is still no consensus about an effective, but safe, working method for removal of adhesive resin after debonding. In this study, enamel surface morphology was investigated following the use of two different finishing methods after orthodontic debonding. Materials and methods: 24 intact and healthy premolars, extracted for orthodontic treatment purpose, were selected and examined by stereomicroscope (Axiocom HRC, Zeiss). To exclude the interindividual differences, two brackets were bonded on the split up enamel surface on the buccal side of the crown. The brackets were removed using a pair of de bracket pliers (3M Unitek). After de bonding, the left buccal part of the crown was treated with a high speed tungsten carbide bur and the right buccal part was treated with a low speed tungsten carbide bur followed by the composite polisher (Shofu, Japan). The enamel surface was gold coated and examined by the scanning electron microscope (SEM) at different magnifications (x25, x50, x300, x600). The photomicrographs were evaluated and compared by appearances, damage and roughness of the enamel surface. Results: At debonding, failure only occurred at the bracket-resin interface, this provided an intact enamel surface with the remaining resin. With the stereomicroscope the damaging of the enamel surface was already visible, but became more obvious after examination by scanning electron microscope. At the surfaces treated with the high speed tungsten carbide bur, deep scratches and grooves were visible. The surfaces treated with the low speed tungsten carbide bur combined with the Shofu composite polisher showed fine scratches and pits along the whole treated area. Discussion and Conclusion: Removal of the resin with the high speed tungsten carbide bur causes obvious damaging of the enamel surface. The overall appearance of the surfaces treated with the low speed tungsten carbide bur and polisher is smoother. Although there are no accurate measurements available for the enamel loss, the combination of the low speed tungsten carbide bur combined with the composite polisher provides a relatively sound enamel surface.
| Item Type: | Thesis (Thesis) |
|---|---|
| Supervisor name: | Ren, Prof. dr. Y. and Department of Orthodontics and University Medical Centre Groningen (UMCG) and University of Groningen and Groningen, The Netherlands |
| Supervisor name: | Han, Associate Prof. dr. G. and Department of Orthodontics and School of Stomatology and Wuhan University and Wuhan, China |
| Faculty: | Medical Sciences |
| Date Deposited: | 25 Jun 2020 10:45 |
| Last Modified: | 25 Jun 2020 10:45 |
| URI: | https://umcg.studenttheses.ub.rug.nl/id/eprint/647 |
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