Glucose clearance from different surfaces of human central incisors and first molars.

The study examined the glucose clearance (retention) in saliva at different surfaces of these teeth in 23 subjects. The mouth was thoroughly rinsed for 15 s with 20 ml of a 0.5 M glucose solution. The concentrations of glucose absorbed by small pieces of paper, placed on the mesial, distal, labial (buccal), lingual and occlusal surfaces 3 min after rinsing, were measured using an immobilized enzyme system and an electrochemical sensor. On the maxillary and mandibular central incisors, the glucose concentrations on the labial surfaces were significantly higher than on all other surfaces and lowest on the lingual surfaces. In the mandibular molars, glucose concentrations were significantly higher on the buccal surfaces than on the lingual surfaces. Clear site-specific differences in glucose clearance were thus observed at the different tooth surfaces. It is considered that the differences in the glucose retention rate might be indicative of factors important for the site specificity of dental caries.