Abstract
Ninety-two subjects,37 males and 55 females with completed permanent dentition were divided into normal and crowded dentition groups. With models of the deciduous dentitions, crown width, dental arch width, length and height, basal arch width and length were measured and with the models of the deciduous and permanent dentitions correlation coefficients between the deciduous teeth and permanent successors was analyzed.
The results were:
1. As to crown width of deciduous teeth, the values of the crowded dentition group of the males was a little larger than the normal dentition group. The difference between the normal and crowded dentition groups of the females was larger than that of the males. The values of the crowded dentition group were significantly larger than those of the normal dentition in all kinds of teeth of the upper jaw and in the deciduous central incisor and lateral incisor of the lower jaw.
2. As to dental arch width, the values of the crowded dentition group of the males were significantly smaller than those of the normal dentitions in the measuring position of D-D and E-E in the upper and lower jaws. No significant difference was found between the values of the normal and crowded dentition groups of the females. Their values were close to those reported by the Japanese Society of Pediatric Dentistry.
3. As to dental arch length, the values of the normal and crowded groups of both the males and females were approximately the same.
4. As to basal arch width, the values of the crowded dentition groups of the males was smaller than those of the normal dentition in the measuring position of d-d and e-e in the upper and lower jaws. No significant difference was found however between them.
5. As to basal arch length, the values of the normal dentition group of the males were significantly smaller than those of the crowded dentition in the measuring position of B-M2 in the lower jaw.
No significant difference was found however between those of the males and females in the other position.
The dental arch width of the males with deciduous dentition and crown width of the females with deciduous dentition seemed to be factors in forming the normalor crowded permanent dentition.
