The reinforcement of anchorage is very important in orthodontic approaches to most cases with tooth extraction, especially in cases with deep incisal overbite and increased curve of Spee, which can make bracket bonding difficult or lead to bracket failure easily by mastication so that results in elongation of period of orthodontic treatment and insufficient treatment.
Numerous types of orthodontic appliances have been introduced for incisal opening and anchorage reinforcement, but the use of those appliances is limited because of complexity of structure and the need of patient's compliance.
Recently, we successfully treated the patients with class II malocclusion and deep overbite who visited Orthodontic Department, Faculty of Dentistry, Pyongyang Medical College,
This fixed appliance consists of holding arch which anchors the right and left maxilla first molars, bite plane added to incisal palatal acryl base. This appliance can be used for the purpose of anchorage reinforcement by preventing mesial movement, torsiversion, extrusion of first permanent molar and decreasing incisal overbite.
25 patients with class II malocclusion combined deep overbite and incisal crowding were objected: Experimental group consists of 15 patients treated by holding arch with bite plate, and 10 in control group were treated by palatal arch with bite plane.
After application attachment, incisal overbite was -2.79±0.44㎜ in experimental group and -0.87±0.49㎜ in control group. There was statistically significant decrease in overbite between groups. (P<0.01)
During the leveling of dentition in mandible, experimental group showed much lower bracket failure rates (7.69%) compared with that of control group. (61.54%). (P<0.01)
Anchorage loss of maxilla first molar in experimental group was much lower than control group. As a result, the use of holding arch with bite plate showed a greater effect in orthodontic treatment. Study on effective treatment of class II malocclusion in our department will go on.
