A Longitudinal Study of Continued Tooth Eruption During Adulthood

Abstract

Teeth retain their capacity to continue to erupt throughout life. What is less-well appreciated is that occlusal migration—with corresponding alveolar proliferation—continues as a normal process during adulthood. Historically, this continuous eruption has been viewed as accommodative for the loss of crown height due to serious occlusal abrasion. Nowadays, with only trivial wear, the result of continuous eruption is to increase lower face height during adulthood. This study reports on changes in the mandibular first and second molars in 73 Americans whites (63 females) examined at 17 and again at about 31 years of age. A computer-assisted method was used to measure alveolar and dental changes using the inferior alveolar canal as a fiducial benchmark. Each molar’s image was scaled to the mesiodistal molar crown dimension
measured from that subject’s dental cast. Major findings were: Both lower molars erupted during adulthood to statistically significant extents, more so in men. Alveolar bone proliferated apace with the coronal tooth migration, so the CEJ-to-crestal bone distance did not change in these healthy, young, dentate adults. First and second molar roots increased in length, apparently by the progressive deposition of cementum. Prior studies have documented continuous eruption in peoples with severe occlusal wear; this study shows that comparable increases occur without any macroscopic loss of tooth substance. These normative changes that—assumedly occur in both jaws—have discernible, cumulative effects on lower face height and facial proportions in adulthood.