Morphorlogical Changes Of Class â…¡ Division 1 Malocc Lusion After Bite-opening Treatment With Fixed Inclied Bite Plate

Class 11 division 1 malocclusion with mandibular retrognathia is com- mon in clinic. To treat this kind of malocclusion, the molar relationship must be modified and concomitant deepbite and overjet must be corrected. A removable inclined bite plate can be used for this purpose, but the suc- cess of removable inclined bite plate therapy is strongly dependent upon good patient cooperation. This study was to investigate the effect of max- illary fixed inclined bite plate combined with Edgewise fixed appliance on juveniles with class II division 1 mandibular deficiency problems. Cephalometric and cast records before and after bite-opening of 20 treat- ed patients were evaluated and compared with the 12 untreated control subjects. Results: 1 After bite-opening through 1.8 to 4.2 months, ANB decreased 3. 51 degree, SNA decreased 0. 07 degree, SNE increased 3. 43 degree, mandible body (GoGn) lengthened 1. 33 mm, so sagital relationship was improved. Lower molars elongated 1. 91 mm and at the same time the overbite decreased 2. 58 mm. anterior facial height (Me ?PP) increased 3. 67 mm and posterior facial height (Aro increased 1. 66 mm, while ratio of posterior facial height to anterior facial height decreased 0. 02, sovertical relationship was improved. 2 Soft tissue changed significantly with hard tissue. SNi increased 2. 54 degree, LiSiN increased 17. 31 degree, Si decreased 2. 12 mm, so patient's lateral profile was improved. 3 The fixed inclined bite plate stimulated the adaptive growth of condyle. 4 Clinical crown height of upper premolars ~. lower premolars and lower molars increased. Width between left and right premolars in upper and lower arch increased while decreased between lower molars. The sagi- tal and transverse relationship between upper and lower arch was advanta- geously modified. Conclusion: The fixed inclined bite plate is small in size, and can be made easily. It continuously works and opens the bite effectively. In this way it modi- fies the molar relationship in class I division 1 malocclusion. Edgewise appliances should be subsequently used to position the teeth to a stable oc- clusion. The fixed inclined bite plate can stimulate the growth of mandible and the remodeling of temporomandibular joint. It also affected the elon- gation of teeth.