Does the basement membrane control the mitotic activity of the inner dental epithelium of the embryonic mouse first lower molar

Abstract

In cultured first lower mouse molars, the mitotic index (MI) of the inner dental epithelium was significantly higher than that of the outer dental epithelium (ODE). Trypsin treatment of tooth germs had no effects on the MI. In heterotopic associations between ODE and trypsin-isolated dental papilla, the MI increased in comparison with the MI of ODE in isotopic associations between IDE and dental papilla. In heterotopic associations between ODE and EDTA-isolated dental papilla which remained covered by a continuous, intact basement membrane, the MI and the labeling index of ODE were significantly higher than those in heterotopic associations of ODE with trypsin-isolated dental papilla. The possible role of the dental papilla in the control of the cell kinetics of the dental epithelium via mesenchyme-dependent modifications of the BM is discussed.