Chronic metabolic alkalosis, sucrose diet and dentine formation in young rats.

As acid-base status has an effect on bone formation and remodelling, chronic metabolic alkalosis was induced in 3-week-old rats for 6 and 7 weeks with 0.25 mol/1 of NaHCO3 in their drinking water to determine whether it has any effect on dentinogenesis in the molars. One group of rats was fed a high-sucrose diet and the other two a standard diet. The control groups had the same diets but drank distilled water. All the rats were injected with tetracycline to mark the onset of dentine apposition. The alkalotic effect of the NaHCO3 drinking water was confirmed by blood gas analysis at the end of the experiment. After death, tetracycline-marked dentine apposition was measured from sagittally sectioned mandibular molars. Chronic metabolic alkalosis did not affect dentine apposition in the groups with the high-sucrose diet, nor in the groups with the standard diet at 6 weeks, but reduced it significantly in first and second molars in 7 weeks at rats on the standard diet. A high-sucrose diet alone caused a greater reduction in the amount of dentine. The general growth of the rats was not affected in any of the groups.