Objectives: The objective of this retrospective cast study was to determine the possibilities of tooth movement with the tooth positioning appliance (syn. positioner) made of the thermoplastic material Bioplast (Scheu-Dental, Iserlohn, Germany). The data collecting process and the measurements should be done by specially developed digital computer-based methods. Patients and Methods: 738 teeth of 28 individuals, treated in the Department of Orthodontics at the Ludwig-Maximilians-University Munich, were examined over the time period of treatment with the positioner. The casts at the end of multiband/ multibracket treatment, the setup models and the casts at the end of positioner treatment were digitalized. These digital images were measured and then examined by the computer software programme DiagnoseFix 2001. The results were mathematically categorized and statistically analysed with SPSS 10.0, mostly using non-parametric tests. Results: The positioner is not so efficient in the prevention of a relapse. However the Bioplast positioner can move teeth effectively according to the setup in a sagittal and transversal direction and rotate them. The extent of movements is nearly independent of anamnestic parameters as is age or gender of the patient. For all kinds of movement one should consider an overcorrection in the setup of approximately a third larger than the desired result. The positioner-induced tooth movements were about 5° in rotation, 0.6 mm in the sagittal direction and 2.2 mm in the transversal direction. It was also found that there is quite a large interindividual range concerning the success rate while the different teeth showed a much smaller range. Conclusions: The Bioplast tooth positioner can be successfully used at the end of orthodontic treatment for fine tuning. It should only be used for a short period of time. Then, in the retention phase, conventional retention appliances like bonded lingual retainers or Hawley retainers should be used.

Back to the Dental Materials: VIII - Others-Non-metallic Program
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