Abstract
In order to observe the sagittal relationship between the upper and lower dentition and/or occlusal contacts on an occlusal plane, a computerized image detection system ‘Occlusogram’ was newly developed in our department. In the present study the ‘Occlusogram’ was introduced and sagittal occlusal changes from the primary to permanent dentition were evaluated.
The subjects examined in the study were 14 children with primary dentition,14 children with early mixed dentition,14 children with late mixed dentition and 15 adults with permanent dentition, who all had healthy and normal occlusion. Cast models of the dentitions and bite checks obtained by black silicon paste in the intercuspal position were used in the study. Each outline of the upper and lower teeth, and occlusal contacts input by a CCD camera to a computer were superimposed on the occlusal plane according to the standard line. To assist analysis five standard points, an incisor point, bilateral canine points and bilateral molar points were defined. Fifteen measuring items were then evaluated and the following results were obtained.
1) A significant increase in the arch width of both jaws was found, whereas the arch length of the lower jaw decreased with dentitional growth.
2) The length from the incisor to the molar point of both jaws increased significantly with dentional growth.
3) As the dentition developed the lower molar point migrated mesially compared to the upper molar point.
4) As compared to the upper incisor point the canine point of both jaws moved disto-buccally, and the molar point of both jaws moved mesio-buccally relatively.
As observation of the dentitional relationship between both jaws in the same plane became possible, ‘occlusogram’ was considered to te useful for examination in occlusal guidance.
