RESUMO
OBJECTIVE@#To examine the expression of myofibroblast in gingival after orthodontic loading.@*METHODS@#Eight patients were selected as experimental group and treated with orthodontic force for 4 months. Ten patients were selected as the control group, were not loaded. The gingival protein expressions of collagen typeⅠ, collagen type Ⅲ, α-smooth muscle actin (α-SMA) were evaluated by immunohistochemistry method.@*RESULTS@#Positive expressions of collagen typeⅠ, collagen type Ⅲ were founded, while no positive staining for α-SMA in the gingival tissue except vascular epithelium before loading. In experimental group, collagen type I and collagen type Ⅲ were increased after orthodontic loading (P<0.05), the expression of α-SMA was detected and statistically significant (P<0.05).@*CONCLUSIONS@#The myofibroblast exists in gingival tissue after orthodontic loading, and it may be concerned with orthodontic teeth relapse.