IDJ 2412-Joiner.indd

Objectives: Through the understanding of tooth enamel science and insights into the beneficial role calcium can play in the caries process, a novel fluoride toothpaste has been developed containing micro-calcium. This paper describes a series of in vitro studies to assess delivery of the micro-calcium to a plaque biofilm, delivery of radiolabelled micro-calcium to subsurface enamel lesions and the rehardening of acid softened enamel by this novel toothpaste. Two clinical studies evaluated the delivery of calcium to the mouth. Methods: Uptake of micro-calcium to a plaque biofilm was assessed using a Calgary Biofilm Device and measuring the calcium levels delivered to the biofilm from the micro-calcium containing toothpaste, a calcium carbonate toothpaste, a silica toothpaste or water controls. Sound and subsurface enamel lesions were treated with 45Ca labelled micro-calcium toothpaste in an in vitro pH cycling study and the uptake of labelled calcium determined. Acid softened enamel specimens were treated with either the micro-calcium containing toothpaste, a calcium carbonate toothpaste or a non-fluoride silica toothpaste in an in vitro remineralisation protocol and the changes in surface microhardness measured. Calcium delivery in vivo was determined in two double-blind, randomised cross-over studies. Subjects brushed their teeth for one minute with either the micro-calcium containing toothpaste or a silica toothpaste. Immediately after brushing and at fixed time intervals up to one hour, unstimulated saliva samples were taken and the total calcium concentration determined. Results: Significantly (p<0.05) more calcium was delivered to a plaque biofilm from the micro-calcium containing toothpaste than the controls. The radiolabelled micro-calcium study demonstrated the uptake of calcium to subsurface enamel lesions. In the remineralisation study, acid softened enamel became significantly harder (p<0.05) following treatment with the micro-calcium containing toothpaste than compared to the control toothpastes. It was shown in the two clinical studies that more calcium was delivered to the mouth following the use of the micro-calcium containing toothpaste than compared to the silica toothpaste. The product differences were in excess of 50% and were of statistical significance (p<0.001). Conclusions: The studies show that the new toothpaste containing micro-calcium delivered elevated levels of calcium to the mouth, promoted enhanced remineralisation of demineralised enamel lesions and thus can help repair early signs of tooth decay.