Publikationsserver der RWTH Aachen University
Die Schaffung retentiver Strukturen im Zahnschmelz mittels Er, Cr:YSGG-Laser : unter Berücksichtigung der Befestigung kieferorthopädischer Brackets
Abstract
dc:descriptionThe aim of the present study was to examine, if it is possible to create retentive structures on dental enamel by means of an Er,Cr:YSGG laser (( = 2790 nm). As reference procedure thereby the conventional acid etching technique served. The results were judged particularly on an orthodontical application, i.e. the temporary bracket bonding. To this end, natural tooth surfaces were irradiated with 10, 20 and 30 J/cm² and examined afterwards with the help of scanning electron microscopic evaluation, roughness measurements and tensile tests. The SEM pictures of Er,Cr:YSGG laser irradiateded surfaces displayed rough surfaces, which are very similar to acid etched enamel. The prism structure of the enamel emerged clearly by a loss of inter and intraprismatic substance. However the clarity of these structures came to a loss with increasing laser energy. The roughness measurements showed with the lowest energy density of 10 J/cm² an ablation, which on the average already exceeded the maximum values of acid etching. During higher energy levels the reference values were exceeded and it came to a clear material loss. In order to judge the quality of the bonding between adhaesiv system and enamel tensile bond strength tests were performed. In clinical outcome a bond strength between 4-8 mPa is considered to be necessary. Only the surfaces irradiateded with 30 J/cm² achieved this clinical limit. Lower laser settings could not achieve the required adhesion. In a further scanning electron microscopic investigation the underside of the bracket base was examined after debonding. The bases were completely covered with composite. These surfaces were covered with pieces of cracked enamel, which suggests a small bond strength and a loosening of the hard tissue structure. Due to a too high loss of hard tissue and a strong loosening of the tooth structure the application of the Er,Cr:YSGG laser for conditioning of dental enamel for bracket bonding can not be recommended. The application of this laser for enamel conditioning with fissure sealing or composite filling therapy is however conceivable.
Degree
thesis:*- Grantor dc:publisher
- Publikationsserver der RWTH Aachen University
- Year dc:date
- 2001
Author and committee
dc:creator, dc:contributor.*- Author dc:creator
-
- Rott, Stephanie
- Contributors dc:contributor
-
- Gutknecht, Norbert
Subjects
dc:subject × 2Rights
dc:rights- Statement dc:rights
-
- info:eu-repo/semantics/openAccess
- Language dc:language
- ger