Twelve female Wistar rats received 1.5 mg/kg of colchicine (CLC) intravenously. Control animals were similarly injected with isotonic saline solution. The animals were killed 5 h, 24 h, 3 days and 7 days after injection. Ninety minutes prior to sacrifice, all animals received an intraperitoneal injection of ³H-proline. Autoradiograms of maxillary incisors showed that CLC increased the retention of the labeled precursor in the odontoblasts. It was also shown that the odontoblasts in the different sectors of the rat incisor present different sensitivities to the CLC action.

-It was studied the influence of the antimitotic drug 5 -fluorouracil (5-FU), administered to pregnant rats, on dental germ formation of newborn rats. A total of 125 female aged 90-100 days and 15 male adult rats (Rattus rattus norvaegicus, albinus, Wistar) were used. The drug was injected intraperitoneally in single doses to females at the 9 th , 10 th , 11 th , 12 th and 13 th days of pregnancy. The animals were divided in four groups according to the doses administered: 10, 20, 30 and 40 mg/kg. Results show that the drug induced no toxicity to mothers, other than loss of body weight with higher doses (30-40 mg/kg), but caused in the fetuses dental germ anomalies and body external malformations. The proportion of such anomalies were, besides dose dependent, influenced by the day of pregnancy when the drug was administered to the mothers: there was a greater sensitivity at the 9 th day and a lesser one at the 10 th day. Higher doses (30-40 mg/kg) caused frequently embryonic death or fetal uterine reabsorption. Agenesia of the dental germ was frequently found.Key Words: antimitotic drugs; 5-fluorouracil; dental germ; fetal malformation.RESUMO -Foi estudada a influência da droga antimitótica 5-fluoruracil (5-FU), administrada a ratas prenhes sobre a formação do germe dental de ratos recém nascidos. Foram utilizadas 125 fêmeas com 90-100 dias de idade e 15 machos adultos (Rattus rattus norvaegicus, albinus, Wistar). A droga foi injetada por via intraperitoneal a ratas grávidas, em doses únicas, aos 9 º , 10 º , 11 º , 12 º ou 13 º dias de gestação. Os animais foram divididos em quatro subgrupos de acordo com a dose administrada: 10, 20, 30 e 40 mg/kg. Os resultados mostraram que nessas doses, o 5-FU não teve efeito tóxico nas ratas prenhes, alem de perda de peso com doses mais elevadas (30-40 mg/kg), enquanto causou anomalias dentais nos embriões, bem como malformações externas. A proporção de tais anomalias foi, alem de dose dependente, influenciada pelo dia de gestação no qual antimitótico foi administrado às mães: foi observada maior sensibilidade ao 9 º dia e menor ao 10 º dia. Doses mais elevadas (30-40 mg/kg) causaram freqüentemente morte do embrião e reabsorção fetal. Agenesia do germe dentário foi freqüentemente observada.Palavras-Chave: drogas antimitóticas; 5-fluorouracil; germe dentário; malformações fetais.

A study was carried out on the effects of the human amniotic membrane (HAM) during wound healing fresh extraction dental sockets on rat maxillary incisors after HAM implantation. Material and Methods. A new method of HAM storage was developed and was denominated as Modified Criovac Technique, which can be divided into 3 phases: cell disintegration, dehydration, and sterilization by gamma irradiation. This method increased the membrane life time, is safe and its sterilization was effective, facilitating the future use of the material. Experiments were performed in 30 male rats, with an average weight of 320 grams each. The animals were divided into 2 groups: experimental and control. The observation times were 2, 7, 14, and 30 days. Three animals of each group were sacrificed, and the specimens were processed for histological routine. Results. Studies under light microscopy revealed that HAM was biologically compatible with bone tissue, did not show signs of rejection. In addition, we observed resorption of HAM during healing time that has been increased at the dental socket because of HAM presence.