Abstract
The authors had reported that C 57 BR/cdJ and C 57 L/J strain mice showed high rates, and C 3 H/HeJ, AKR/J and RF/J showed medium rates, and A/HeJ and C 57 BL/6 J showed low appearance rates of the gutter shaped root. We investigated whether the M 2 had gutter shaped root indicated absolutely and relatively a degenerating tendancy or not by measuring the buccolingal and mesiodistal diameters of M 1 (lower the first molar), M 2 (lower the second molar) and, M 3 (lower the third molar), and the root length of M 2 in the above seven inbred strains of mice having different appearance rates of the gutter shaped root. The following were the results of the present study.
1. The buccolingual and mesiodistal crown dimensions of each molar did not show small or large tendencies in two strains with high appearance rates compared with the medium and low appearance rates of the gutter shaped root.
2. The rates of the mesiodistal crown diameters of M 2 with the gutter shaped root for three molars of seven strains of mice did not show small and large tendencies compared with those of the low and medium appearance rates of the gutter shaped root as a relative analysis.
3. The root length of M 2 in two strains of mice with high appeared rates of the gutter shaped root were significantly longer than those of other strains.
The results suggested that the gutter shaped root did not appeared as degeneration but as deformation by mutated genes.
