Date of Award

Spring 2009

Document Type

Thesis - Restricted

Degree Name

Master of Science (MS)

Department

Dentistry

First Advisor

Liu, Dawei

Second Advisor

Bradley, T. G.

Third Advisor

Bosio, Jose

Abstract

The purpose of this pilot study was to construct a mouse model to investigate orthodontic tooth movement (OTM) and to explore the possibilities of using microCT scanning to gain a better understanding of the spatial changes. Twenty eight inbred mice (strain C57BLK/6J) were randomly divided into four groups: 1) Pure control (n=4) 2) Sham control - splint only (n=8) 3) OTM (n=8) 4) OTM + Splint (n=8). An OTM appliance was inserted into the undercuts of the first maxillary molars of the experimental groups and submental vertex radiographs were taken each week. Upon euthanization and fixation, the jaw samples were scanned using microCT. To study the effects of "chewing,"hyperfunction was created within the "OTM +Sp" group by the placement of resin on one of the maxillary first molars, while the countralateral side experienced hypofunctioning. Submental vertex measurements (using a custom software program) showed that the hyperfunction side initially had greater rate of movement during week one. However, in weeks 2 and 3, the hyperfunction side showed a slow rate of orthodontic tooth movement when compared to the hypofunction side. MicroCT offers a qualitative assessment of the displacement of teeth resulting from orthodontic forces. As this is a pilot study, limitations are expected. The high standard deviation has a wide distribution due to small sample size and multifactoral errors. A larger sample size and improvements in radiological methods and techniques may produce more reliable and repeatable results. With alterations in the protocol design, the mouse model can be used to further investigate the impact of chewing or mechanical vibration on OTM rate and histological changes.

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