Effects Of Unilateral Temporalis Removed,Masseter Blocked On The Growth And Development Of Mandible

[Objective]The aim was to investigate the effect of Muscles' Imbalance on the bilateral mandibular condylar cartilage and the lower jaw.[Methods]Sixty 4-week-old male rats were randomly divided in to 2 groups,excise the unilateral temporalis and masseter respectively.Six rats were killed under deep anesthesia after 2,4 and 6 weeks.The hibateral mandibulars were removed for mendibal measurement.The temporomandibular joints were used for HE staining. The expression of CTGF in condylar cartilage was observed by immunohistochemical staining.[Resultsl the development of bilateral mandibulars were asymmetric,the non-surgical side of the mandible were lenger than the operative side;HE staining showed that the experimental group with bilateral condylar cartilage of pathological changes and changes in cartilage thickness have occurred,no difference between left and right side in the experimental group,there were difference between the experimental group and the control group at the same time poin;Immunohistochemical staining showed that CTGF expressed in proliferative layer,chondroblast layer and hypertrophic layer of the condylar cartilage.Quantitive analysis showed that CTGF expression in the experimental group were increased,there was no significant difference between left and right side in the experimental group,the expression of CTGF after 6 weeks of operation was stronger than the group after 3 weeks of operation,the expression of CTGF after 9 weeks of operation was stronger than the other groups.[Conclusions]The construction activity of jaw musclces provide power to the mandible's motion.The occlusion,musclces and TMJ are tied up physiologically, the jaw musclces' normal function is very important for the mandible's development,especially for the mandibular condyle' development and the TMJ's functional stability.Stress variation can up-regulate the expression of CTGF mRNA in rabbit mandibular condylar chondrocytes.It is involved in the stress-mediated mandibular condylar cartilage remodeling.