Volumetric and morphologic changes due to effect of unilateral extraction of teeth

Objective: Chewing includes the rhythmic movement of the jaw muscles. In this study, we investigated volumetric changes in the masticatory muscles and morphometric changes in the mandibular condyle due to unilateral extraction of the teeth in the sixth and twelfth weeks of life. Materials and Methods: Eighteen rats were used. The rats were divided into three groups. In the experimental groups (Groups I and II), all of the teeth on one side of the upper and lower jaws of the rats were extracted. In the control group all the teeth were intact. Volumetric changes of the masseter and temporal muscles were evaluated. In addition, morphometric changes of the mandibular condyle were investigated. Results: The measurements performed six weeks after tooth extraction did not reveal any difference in the temporal muscles between the two sides, however the volume of the masseter muscle on the side of the extraction was significantly reduced (Group I). Twelve weeks after the tooth extraction, the volumes of the masseter and temporal muscles showed significant reduction on the side of the extraction (Group II). A morphometric reduction in the mandibular condyle was observed in the longer period of time. No asymmetry was observed either for muscular volumes or for mandibular condyle dimensions in the control group. Conclusion: Unilateral tooth loss may cause volumetric reduction in the masseter and temporal muscles ipsilaterally. However, the cause of the morphometric reduction in the mandibular condyle on the contralateral side in the longer period of time is surprising