The Influence Of Lateral Pterygoid Muscle On The Shape And Function Of TMJ And Pathology During The Healing Process Of Rigid Internal Fixation SFMC

Experiment OnePurpose: Evaluate the influence of lateral pterygoid muscle to TMJ configuration and function during the healing process of rigid internal fixation SFMC through built SFMC rigid internal fixation animal models after anatomical reduction, in order to provide evidence for further research and clinical treatment.Material & method: Take 12 healthy one year old male sheep for experiment. Randomly number them from 1 to 12 and mark on their bodies. Divide all the sheep into 2 groups randomly, one is retained lateral pterygoid muscle and the other one is cut off lateral pterygoid muscle.Make the sheep SFMC artificially to built SFMC models, then knock in lag screw from condylar stump cross to make condylar fracture blockand and bone stump reach anatomical reduction, thus rigid internal fixation SFMC animal models are successfully built. Execute experimental animals after 4 weeks,8 weeks and 12 weeks from the surgery, observe and measure the weight,maximum mouth opening, protrusion distance,the range of jaw movement,changes in internal and external diameters of mandibular condyles and the formation condition of new bone through CBCT and 3D reconstruction of changes of condylar.Result:(1)Compared with the group of cut off lateral pterygoid muscle experimental animals' maximum mouth opening, protrusion distance and the range of jaw movement showed more significantly. P<0.05(statistically significant).(2) The group of retained lateral pterygoid muscle showed noticeable differences on change in internal and external diameters of mandibular condyles to cut off lateral pterygoid muscle group. Moreover,the differences grew more significant with the further time elapsed(p<0.05).(3)Compared with group of cut off lateral pterygoid muscle, the group of cut off lateral pterygoid muscle showed more changes in morphology of condylesConclusion:(1)After rigid internal fixation,during the healing process of SFMC lateral pterygoid muscle has an influence on the function of TMJ.(2)During the healing process of SFMC, lateral pterygoid muscle influences the changes of morphology of condyles and provides a promoting effect to the rebuilt of the condyles shape.(3) Whether it is suggested cutting off lateral pterygoid muscle or not, needs to be further researched.Experiment TwoPurpose: On the basis of Experiment one, further study the dynamic changes of lateral pterygoid muscle to TMJ during the healing process of rigid internal fixation SFMC, and provide relevant support for further research.Material & method: Take 12 healthy one year old male sheep for experiment. Animal number, model preparation and experimental group were the same as experiment one. Animals are killed at 4 weeks, 8 weeks and 12 weeks after operation. After taking CBCT,cut and strip out the complete temporomandibular joint. Fix, decalcify and embed tissue sections, then stain the joint with HE. Observe the morphological and structural changes of TMJ through optical microscope.Results: More new bones are formed in the animals of retained lateral pterygoid muscle group.Conclusion:(1)Lateral pterygoid muscle has a promoting effect to formation of new bones during the healing process of SFMC rigid internal fixation.(2) Whether it is suggested cutting off lateral pterygoid muscle or not, needs to be further researched.