Dentition, bone loss, and the aging of the mandible.

BACKGROUND: Facial aging is a dynamic process with impact on both the soft tissues and the bones. Despite a growing body of evidence, controversy still exists regarding absolute characteristics of the aging facial skeleton.

OBJECTIVE: The purpose of this study was to investigate various mandibular measurements in different age groups and to delineate the relation of the dentition to these parameters.

METHODS: Ninety Caucasian mandibles were assessed for the following distance landmarks: gonion-gonion, infradentale-gnathion, mental foramen-mandibular crest, mental foramen-inferior mandibular border, gnathion-gonion, condyle-gonion, and gonial angle. The measurements were compared according to age, sex, and dentition.

RESULTS: The number of teeth decreased significantly with increasing age in males (P = .002) and females (P < .001). There were no other statistically significant differences between age groups for the rest of the parameters. The infradentale-gnathion distance (P = .005) and the mental foramen-mandibular crest distance (P < .001) was found to increase with total number of teeth. Other parameters did not show a significant relation to dentition. All parameters were significantly larger in the male subgroups with the exception of gnathion-gonion distance and gonial angle. Bilateral mandibular measurements were symmetric except for the gonial angle, which was more obtuse on the right side in males (P = .007) and females (P = .018).

CONCLUSIONS: Our findings support previous evidence that dentition is the main determinant of the morphology of the mandible. The skeletal characteristics are variable among individuals, and a longitudinal study is required to better understand age-related changes of the mandible.