Animal Experimental Research On The Alveolar Surgery-aided Rapid Orthodontic Tooth Movement

Wearing orthodontic braces may become a social handicap for some patients, especially adult patients, thus they want to shorten the orthodontic treatment. However, classically the orthodontic tooth can only be moved in a slow rate for the sake of the health of the orthodontic tooth and periodontal tissues around it, which leads to the lengthening of the treatment. How to move the teeth safely and quickly is of great concern for the orthodontist.The aim of the study was to examine the effect of alveolar surgery on orthodontic tooth movement and to learn whether alveolar surgery can be a safe and effective way to facilitate the orthodontic tooth movement.Dogs were selected as subjects in the study. Extraction of the second premolar plus alveolar surgery to reduce the osteal resistance in the path of tooth movement was performed on the experimental side, whereas on the contralateral side, only the second premolar extraction was included. The third premolars were taken as anchorage to retract the first premolar. Ni-Ti springs were exploited to produce constant orthodontic force to distalize the first premolar on the experimental side and the control side. The effect of alveolar surgery on orthodontic teeth movement was investigated by following methods: measuring the distance of tooth movement, apicalradiographic examination, histological slices and self-fluorescence. The results showed that:1. Lessening the osteal resistance along the path of tooth movement makes the tooth move more quickly. The distal movement of the first premolar on experimental side was 4.31 ± 0.46mm during 4 weeks, which almost twice 2.16 + 0.42mm of the control side .2. The rule of movement on the experimental side is the same as the classic model, but the velocity of tooth movement increased almost twice.3. Hyalinization on pressure side is not obvious. Direct bone resorption occurred in the early stage of tooth. Active and extensive bone resorption can be observed on the pressure side. Cells on tension side proliferate prosperously with active deposition of bone4. Obvious root resorption and irreversible injury to the pulp has not been observed in the study.5. Self-fluorescence results indicate that more new bone were deposite on tension side of the experimental side.Results from this study indicate that alveolar surgery can speed up the tooth movement without injury to the orthodontic tooth itself and the periodontal tissue, and suggest that alveolar surgery may serve as an effective and safe way to aid orthodontic tooth movement.The mechanisms for the rapid movement in the study may be: ? decreased bone resistance along the path of tooth movement ?continuous light force; ?rare hyalinization on pressure side and extensive resorption; (Dactive deposition of bone on tension side.