Histological changes of lateral pterygoid muscles of SD rats in unilateral mastication

Objective To study histological changes of lateral pterygoid muscles of SD rats in unilateral mastication.Methods Thirty SD rats were employed to accomplish this study.Twelve of their molars were extracted and other twelve were given the teeth-division.The remaining six rats served as the control group.After six weeks their masseters and lateral pterygoid muscles were excised and observed with light microscope and electronmicroscope.Results Lateral pterygoid muscle fibers suffered from considerable cell and tissue degeneration and reconstruction in experimental groups.The working side was observed to show no significant difference from the non-working side.The injury of lateral pterygoid muscle was more serious than masseter.Conclusion The study demonstrates that unilateral mastication may cause certain injury to pterygoid muscles.However,it cannot be concluded that lateral pterygoid muscle plays a key role in TMD revoking.