Organ culture study of effect of Vitamin- A-deficiency on rat third molar development

Abstract

A culture procedure for rat third molars suitable for nutritional-developmental studies is described. Urerupted third molars from 12-day-old rats were cultured in BGJ b media containing 20 per cent rat serum and supplemented with 25 mM HEPES buffer, 25 mg ascorbic acid, 20 mg L-glutamine, 12mg penicillin G and 10mg streptomycin sulphate per 100 ml of media. Molars were cultured at the liquid-gas interphase using a 50 per cent O 2, 45 per cent N 2, 5 per cent CO 2 gas mixture at 10 lb-psig (pounds per square inch guage). Molar cultures were maintained successfully for 9–14 days without evidence of necrosis, although they developed at a slower rate than in vivo. Molars cultured in 50 per cent O 2 compared to those cultured in 21 per cent O 2 for periods of 2, 4, 6 and 8 days had higher values for protein, alkaline phosphatase (AP), Ca, P and Ca/P. Vitamin- A-deficiency gave lower values for AP, Ca, P, Ca/P, 45Ca, 35S and [ 14C]-proline uptake. Histologically, A-molars had atrophie ameloblasts, some foci of squamous metaplasia and abnormal keratin formation. Thus, deficiency of vitamin A imposed during in-vitro development of rat third molars retarded dentinogenesis and interfered with early mineralization of enamel and dentine.