In order to clarify the changes in function that accompany physiological root resorption of deciduous teeth in children, mandibular deciduous second molars were photographed by the standard procedure in children whose Hellman's dental stage ranged from IIA to IIIB, and root resorption was classified on the basis of the X-ray films. The occlusal force of the mandibular deciduous second molars, occlusal contact area, occlusal pressure, and distance from the mandibular deciduous second molar to the succedaneous permanent teeth germ were compared in various stages of root resorption and at various dental stages. Relationships between the occlusal force and the occlusal contact area and between the occlusal force and distance were determined, with the following results obtained.
1) The occlusal force and the occlusal contact area tended to decrease with increases in the degree of root resorption and dental stage.
2) The occlusal pressure showed only slight changes before the stage of resorption of about 1/2 of the root, but tended to decrease in the stage of resorption of about 3/4 of the root.
The occlusal pressure in each dental stage, however, showed no tendency to decrease.
3) The above results suggest that changes in physiological root resorption of deciduous teeth influence occlusal function in children.