Dental arch depth and width studied longitudinally from 12 years of age to adulthood

Abstract

This investigation was designed to study dental arch depth and arch width in male and female subjects from the age of 12 years to adulthood. Arch depth and width measurements were taken from dental casts of twenty-six subjects at annual intervals from 12 to 17 years of age and at an additional examination of these subjects after they had reached the age of 23 years. The age range of the subjects at the time of the additional examination was 23.2 years to 30.1 years. The mean age was 26.3 years. All subjects were North American Caucasians with acceptable occlusion. Summarily, selected findings are as follows: 1. 1. Means for both maxillary and mandibular arch depth decrease with age throughout the period studied in each sex, with the rate of change being less after the age of 15 years. The mean decrease in mandibular arch depth from 12 to 26 years of age was 3.2 mm. for male subjects, or approximately a 10 per cent decrease. For female subjects, mean decrease in arch depth was 2.6 mm., or approximately a 9 per cent decline. 2. 2. For female subjects, means for arch width in each arch revealed no significant change during the 14-year span from 12 to 26 years of age. In males there was a small statistically significant increase in arch width from 12 to 15 years of age. 3. 3. Every person in the study showed a decrease in arch depth after the age of 15 years. The range of decrease in the mandibular arch for the period from 15 to 26 years of age was 0.1 mm. to 2.3 mm. For the same age group, 92 per cent of the decreases were in excess of 0.75 mm. and 46 per cent of the decreases were in excess of 1.25 mm. 4. 4. No evidence was found to reject the null hypothesis of no sex difference in mean change in arch depth for any of the age intervals studied. 5. 5. A moderate negative association (r = −0.55) was found between (a) arch depth decrease from 12 to 14 years of age and (b) arch depth decrease from 14 to 26 years of age. 6. 6. Individual comparisons of four subjects were presented, demonstrating the constancy of direction but variability in amount of arch depth decrease from age 12 to early adulthood.