| Objective: To compare the effect of two extraoral appliance---extraoral Arch and J-hook in treating class II division I malocclusion through Cephalometric evaluation ofsoft and hard tissue change during treatment; To evaluate the characteristics of thesetwo extraoral forces; To improve evidence based therapy in this area, Providereference for the clinical diagnosis and treatmentMethod:Cephalometric radiographs of30young patients with Angle class IIdivision1malocclusion，15treated with facebow and15with J-hook, wererandomly selected from orthodontic department，stomatology hospital，NanchangUniversity. Cepholometric evaluation was used to assess the soft and hard tissuechanges before and after treatment. T-test was used for statistical analysis.Result:1、Changes in sagittal directionSNA angle decreased in both two groups after treatment, but J-Hook groupdecrease more（P＜0.01）. SNB angle increased in both two groups after treatment,mandible growth were improved while maxillary growth were restrained;prominent maxillary central incisor retraction and inhibited maxillary molarmesialization were observed in both groups, U1/SN angle in J-Hook group is betterthan facebow group.2、Changes in vertical directionU1-PP length and the ratio of posterior to anterior facial height were increasedin j-hook group but not in facebow group, OP/FH were decreased in J-hook groupbut increased in facebow group with statistical significance （P＜0.05）3、Changes in soft tissueA significant improvement in soft tissue profile were observed in both groups,upper and lower lip were retracted after treatment．The increase in Z angle hadstatistical significance（P＜0.01）.but the changes had no difference between thetwo groups． Conclusion:Either facebow or J-hook treated Angle class II division1malocclusion patientscan achieve normal occlusion and obtain profile improvement．In comparison withfacebow， J hook performs better in anterior torque controlling, anterior incisorretraction and occlusional plane controlling. |
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