The effect of ovariectomy and high-sucrose diet on dentine formation and caries in growing rats.

Ovariectomized (Ovx) or sham-operated (Cnt) and tetracycline-labelled growing rats were fed either a commercial powdered standard rat diet (Ovx and Cnt) or a high-sucrose diet (Ovxsuc and Cntsuc). All animals were inoculated in the mouth with Streptococcus sobrinus. At 11 weeks of age the areas of caries lesions and dentinal apposition of the first and second molars and the areas of the pulpal cross-section of the incisors were determined. The area of dentinal apposition was largest in Cnt animals, the difference being statistically significant only in comparison with the Cntsuc animals. No such difference between the diets was found among the Ovx animals. The cross-section of the pulpal chamber was smallest in the Ovxsuc rats and largest in the Cnt animals, but no statistically significant differences were found between the groups. The caries lesions were significantly larger in Ovx, Ovxsuc and Cntsuc animals than in Cnt ones. Ovariectomy thus increased caries progression in growing rats, but the effect on dentine formation remained negligible. In this respect there is a difference between primary and secondary dentinogenesis.