Purpose: The purpose of this study is to assess cortical thickness, height, and width with cone-beam computed tomography (CBCT), and determine the relationship of these parameters with age.
Patients and methods: A total of 113 subjects from the University of California at San Francisco Orthodontic Clinic with a CBCT scan were enrolled. Subjects were stratified by age in decades. Thickness of buccal and lingual cortices and mandibular height and width were evaluated in 5 regions (13 sites). A single factorial ANOVA was used to compare the parameters among age groups. P less than or equal to .05 was statistically significant.
Results: There were 44 (38.9%) males; 69 females. For all groups, the thickest to the least thick cortical plates were: base of the mandible, lower buccal one third, upper lingual one third, upper buccal one third, and lower lingual one third. In all groups, the mandible increased in height as the midline was approached, and the width of the upper third of the mandible decreased from the second molar to the symphysis whereas the reverse occurred in the lower third. Comparison of the age groups showed that subjects 10 to 19 years old had thinner cortical plates than other age groups (P <or= .05) with peak thickness in subjects 40 to 49 years old. The subjects 10 to 19 years old also had lower posterior mandibular height (P <or= .05). There was no statistical difference in width among the groups.
Conclusions: The mandibular cortical bone is thickest at the base, on the buccal side. Subjects who are 10 to 19 years old have thinner cortical bone and decreased mandibular height compared with all other age groups. The mandible continues to mature through 40 to 49 years of age and then decreases in thickness after this period.