不同类型反[牙合]冠状面咀嚼模式分析

目的阐明不同类型反(牙合)冠状面咀嚼模式方法选取12-35岁109名不同类型反(牙合)和16-30岁22名正常(牙合)个体。根据冠状面切牙点的运动轨迹将咀嚼模式分为8种咀嚼型。反(牙合)患者按反(牙合)的前后向位置和横向位置分组,Mann-Whitney U 检验比较不同类型反(牙合)组与正常胎及各组之间各种咀嚼型发生频率的差异。结果所有反(牙合)组,正常咀嚼型发生频率明显小于正常(牙合)。后牙反(牙合)组,相对前牙反(牙合)组,反向型发生率高(P=0.002),正常型发生率小(P=0.001).当伴随下颌偏斜和或下颌前突,牙弓段反(牙合)时,后牙反(牙合)的反(牙合)侧或下颌偏斜的偏斜侧,反向及反向交叉型比对侧易发生。结论在冠状面上,后牙反(牙合)组比前牙反(牙合)组呈现出更多的异常咀嚼型,后牙反(牙合)可能是反向及反向交叉咀嚼型的促成因素,尤伴有下颌偏斜,下颌前突及牙弓段反(牙合)时更明显。

A clinical analysis on frontal chewing patterns with different crossbite malocclusions

Objective To clarify the chewing patterns with different crossbite malocclusions. Methods The sample was composed of 109 crossbite malocclusion subjects aged 12-35 years and 22 normal occlusion subjects aged 16-30 years.The chewing patterns were classified into 8 chewing types according to the shape of frontal incisor point movement.The crossbite subjects were grouped by the anterior- posterior position of crossbite,then by different side.The MannWhitney U test was performed to compare the frequency of each chewing type in each crossbite group with normal occlusion and between crossbite groups.Results In the crossbite groups,normal chewing type occurred much less than that in normal occlusion.In the group involving posterior crossbite,"reverse type" was higher (p=0.002) and the normal type was lower (p=0.001) in frequency in comparison with anterior crossbite group.When accompanied by mandibular shift,mandibuar protrusion,arch crossbite,in the crossbite side or shift side,reverse type and reverse crossing type occurred higher than that in contralateral side.Conclusions In frontal plane,posterior crossbite group may present more abnormal chewing type than anterior crossbite group,and posterior crossbite may contribute to the high frequency of reverse and reverse crossing chewing type,especially when accompanied by mandibular shift,mandibuar protrusion or arch crossbite.