In the blood gas analysis, the experimental methods were proved adequate: moderate chronic metabolic acidosis and mild metabolic alkalosis and respiratory alkalosis were confirmed.
As expected, chronic metabolic acidosis resulted in reduced weight gain. Also, the dentine formation in the molar teeth was slowed down significantly. The primary dentinogenesis is probably easily disturbed: a slight reduction in the growth of dentine was seen in most of the experimental groups.
The high-sucrose diet also markedly reduced the growth of dentine, but apparently by a different mechanism than metabolic acidosis. Firstly, the high-sucrose diet did not induce acidosis in the blood gas analysis. Secondly, alkalosis did not eliminate the reducing effect of the high-sucrose diet on dentine formation. Thirdly, the effects of metabolic acidosis on the mineralization of the dentine in molars were completely different from the previously reported effects of the high-sucrose diet.
Chronic metabolic acidosis increased the weight percentage of calcium and total mineral content in the dentine formed during the experiment. This is different from the results reported in bone and probably due to the lack of resorption and remodelling in dentine.
Metabolic acidosis and respiratory alkalosis promoted the initiation and progression of the dentinal caries. This was only seen in the rats with the high-sucrose diet. The third molars were most affected, which implies higher caries susceptibility of erupting teeth with ongoing maturation process, when compared to the erupted ones with more advanced stage of dentinal development, as found earlier. Metabolic alkalosis slightly protected the teeth from caries.
Metabolic acidosis and the high-sucrose diet potentiated each others effects in promoting caries and reducing the growth of dentine in the teeth of young animals. Respiratory alkalosis seemed to be harmful mostly concerning caries and metabolic alkalosis proved to be even slightly beneficial to the teeth.
Answers to the tested hypotheses are:
Sucrose affects odontoblasts causing reduction in dentine formation and acceleration in caries progression via processes other than metabolic acidosis.
Metabolic alkalosis did not eliminate the effects of sucrose on dentine formation, which supports the finding mentioned above.