The Relationship Analysis Of Some Three-dimensional Index Of Adult Mandible And The Distances Of Processus Zygomaticus

Objective :Mandible is a main part of facies cranii, accounting for the most part of one third of inferior occlusalf surface and an important factor for the gross face type. Thus the relationship analysis for some three-dimensional index of mandible and the distances of processus zygomaticus is an important component studying the prosopo-tissue and structure relationship and affecting factors for face type. By the modern three-dimensional reconstruction technology this study analyzes the relationship of some three-dimensional index of mandible and the distances of processus zygomaticus and obtains which indexes are the closest to the distances of processus zygomaticus and face type. By this way we can get the relationship formula of these indexes and distances of processus zygomaticus, by which we can conjecture the various relative mandible indexes which will be useful for getting the normal indexes of patient's face ratio coordination.Methods: Choosing 20-30-year-old men and women of the 15 volunteers randomly, having regular facial features, no facial deformity, no history of orthodontics. Screening the head and neck of each volunteer by spiral CT consecutively and sending the three-dimensional data obtained to compute workstation. Measuring three-dimensional index of mandible and the distances of processus zygomaticus and analyzing these data with SPSS 11.5 statistical software and getting the mean and the ratio relationship and correlation coefficient and formula between various data and distances of processus zygomaticus.Results: There are certain gender differences among The mean of the distance of condyle process,the height of mandible ramus,and the distance of angle of mandible and there are not obvious gender differences between other indexs of mandible and the distance of processus zygomaticus. And there are different radio relationships between the distance of condyle process , the height of mandible ramus , the distance of angle of mandible , the length of body of mandible , the distance between mental point and condyle process and the distance of the processus zygomaticus, which have no statistical significant. The correlation coefficient is 0.4-0.7 between the distance of processus zygomaticus and the some indexes of mandible which is midrange correlative. Among them the highest correlation coefficient is 0.7 between the distances of angle of mandible and processus zygomaticus. The formula has statistical significant according to the distance of the processus zygomaticus as variateY and the distance of condyle process , the height of mandible ramus , the distance of angle of mandible , the length of body of mandible , the distance between mental point and condyle process as independent variable X.Conclusions: Among the obtained indexes of mandible the distance of angle of mandible,the length of body of mandible and the span between mental point and condyle process have standing effects on the distance of processus zygomaticus, which also affects the width of midface greatly.Among these, the distance of angle of mandible has the greatest effect on the distance of processus zygomaticus.