Effects of nicotine on murine incisor development.

The effects of daily injections of nicotine sulfate on incisor development in CD-I mice were studied. Pregnant animals, injected with 0.1% nicotine sulfate at a dose of 1.67 mg/kg body weight from the 6th to the 15th day of gestation, were sacrificed on the 18th postcoital day. The 130 nicotine treated fetuses, as well as the 348 control fetuses were embedded in paraffin and sectioned in the frontal plane. The developing incisors of the experimental fetuses were retarded, less differentiated, and reduced in breadth and length. The developing incisors of the control fetuses were in the early appositional stage of odontogenesis, whereas those of the experimental population were either in the late cap or early bell stage, depending on the presence or absence of palatal cleft, which occurred in 9.6% of the fetuses.