Cementum thickness and mesial drift

Abstract Cementum thickness increases uniformly with age, and questionably from functional stimulation due to tensional forces. Mesial drift of teeth results in tensional forces on distal root surfaces. This study evaluated whether there was any discernible effect on cementum thickness related to mesial drift in humans. The material consisted of maxillary and mandibular bicuspids and molars with their surrounding periodontia from 5 humans (mean age at death, 48.6 years). The teeth and tissues had been sectioned histologically in a mesio‐distal plane, and the analysis for each tooth was done using 3 step‐serial sections from the mid‐buccolingual region. On the mesial and distal surface of each tooth, cementum thickness was measured in μm at 3 defined locations at a level representing the mid‐point of root length for bicuspids and molars. Means from the measurements on mesial and distal surfaces were compared using descriptive and inferential statistical methods. For each individual tooth analyzed, the cementum was thicker on the distal surface (range greater, 32–107%; mean, 69%). The statistical comparisons showed that cementum thickness on the distal surface was significantly greater for bicuspids (mesial, 135 μm: distal, 216 μm), molars (mesial, 154 μm : distal, 284 μm), and all teeth combined (mesial, 154 μm: distal, 284 μm). The magnitude of this difference became greater with increasing age. It was concluded that cementum thickness was markedly greater on the distal surfaces of teeth from adult humans, and that this may be due to functional stimulation from mesial drift over time.