The Effects of Aging on the Eruptive Behavior of the Mandibular Incisor in Male Rats

Several studies have highlighted the lack of age changes in the extracellular matrix of the periodontal ligament, but more needs to be known about cellular and functional changes (including the effects upon eruption). For this study, impeded and unimpeded eruption rates were measured over a 2-week period for the mandibular incisors of a group of 24-month-old rats. The technique used for measuring eruption was similar to that described by Bryer [15]. Both impeded and unimpeded eruption rates were found to be significantly increased ( p < .01) compared with those obtained from a group of rats aged 8 weeks. These changes might be related to changes in the mechanism(s) responsible for the generation of the eruptive force(s) or to changes in the resistance of the tissues to such forces.