The aim of this study was to further define the relationship between cell proliferation and the rate of tooth eruption in the rat incisor. Vinblastine is a drug that blocks cellular mitosis and was used to inhibit cell proliferation in the odontogenic region of rat incisors that were submitted to a shortening treatment or to higher masticatory forces. Male Wistar rats were divided into five groups: normofunctional (control group for incisor eruption), hypofunctional (incisor submitted to eruption acceleration), hyperfunctional (incisors under higher masticatory forces), hypofunctional with vinblastine and hyperfunctional with vinblastine. In incisors submitted to shortening procedures, a significant decrease in the eruption rate and cell proliferation was observed two days after vinblastine injection, suggesting that incisor eruption is dependent on cell proliferation. Anat