• Journal of Dental Rehabilitation and Applied Science
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• v.25 no.3
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• pp.279-285
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• 2009

The purpose of this study was to evaluate histologic result of bone substituting materials on extraction sockets. We compare the histologic findings of control, $MBCP^{(R)}$, $Polybone^{(R)}$. Mandibular premolar teeth of Beagle dogs were extracted available for bone filling. All alveolar extraction sockets were thoroughly debrided with surgical curet to remove the periodontal ligament. The graft materials were filled into the extraction sockets. The animals were sacrified 90 days after implantation. Both treated and control mandibular sites were histologically evaluated with light microscopy. Histological observation at 90 days revealed that control and experimental sites were healed uneventfully without any adverse tissue reaction. Regenerated new bone formation ratio is 34.5% for control, 28.4% for $MBCP^{(R)}$, 23.8% for $Polybone^{(R)}$. From this results, it was suggested that $MBCP^{(R)}$, $Polybone^{(R)}$ are promising bone substituting materials to promote normal tissue healing and new bone formation.

• The korean journal of orthodontics
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• v.41 no.5
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• pp.324-336
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• 2011

Objective: The aim of this study was to conduct three-dimensional finite element analysis of individual tooth displacement and stress distribution when a posterior retraction force of 200 g was applied at different positions of the retraction hook on the transpalatal arch (TPA) of a molar, and over different lengths of the lever arm on the maxillary anterior teeth in lingual orthodontics. Methods: A three-dimensional finite element model, including the entire upper dentition, periodontal ligaments, and alveolar bones, was constructed on the basis of a sample (Nissan Dental Product, Kyoto, Japan) survey of Asian adults. Individual movement of the incisal edge and root apex was estimated along the x-, y-, and z-coordinates to analyze tooth displacement and von Mises stress distribution. Results: When the length of the lever arm was 15 mm and 20 mm, the incisal edge and root apex of the anterior teeth was displaced lingually, with a maximum lingual displacement at the lever arm length of 20 mm. When the posterior retraction hook was on the root apex, the molars showed distal displacement. When the length of the lever arm was 20 mm, anterior extrusion was reduced and the crown of the canine displaced toward the buccal side, in which case, the retraction hook was on the edge, rather than at the center, of the TPA. Conclusions: The results of the analysis showed that when 6 anterior teeth were retracted posteriorly, lateral displacement of the canine and lingual displacement of the incisal edge and root apex of the anterior teeth occur without the extrusion of the anterior segment when the length of the lever arm is longer, and the posterior retraction hook is in the midpalatal area.