Tooth wear, solubility and fluoride concentration of molar-tooth surfaces in rats maintained on simultaneous or separate intake of food and fluoridated drinking water

Structured review of enamel erosion literature (1980-1998): a critical appraisal of experimental, clinical and review publications

OBJECTIVE

To attain an objective account of the methods to measure enamel erosion used in 1980-1998 publications, a structured review of the literature was undertaken.

METHODS

Inclusion and exclusion criteria were applied to 731 clinical/experimental research and review reports. Eighty-five included papers were subsequently rated according to 'hierarchy of evidence' guidelines to assess the strength of the report's design and the relevance of the evidence to replicating enamel erosion in vivo in humans. Scores were assigned to rate each aspect in the guidelines.

RESULTS

A total of 16 clinical, 13 review and 56 experimental papers were assessed; 36.4% were published during 1996-1998. Excluding reviews, 16 papers were qualitative and 56 quantitative; 51 used human enamel. Our classification yielded nine groups of methods (five scoring systems and 26 measurement techniques). CTFPHE (Can Med Assoc J 1992; 147: 443) grading of research reports indicated that 2.8% provided evidence grade I; 20.8%, grade IIa; 63.9%, grade III; and 12.5%, grade IV.

CONCLUSIONS

There has been a consistent increase in the body of knowledge. The overall quality of publications has not substantially changed over time. Experimental studies were more often quantitative, and quantitative studies had better research designs. No single group of research methods had obviously superior research designs.

The dissolution rate of enamel in acid in developing rat incisors

This study was undertaken to determine the changes in this dissolution rate at different developmental stages after different fluoride dietary regimes. Four groups of Wistar rats received water with 0, 25, 50 and 100 parts/10(6) fluoride respectively for 10 weeks. Six exposed windows of 2 mm2 were prepared on the enamel surface of the upper incisors, corresponding to six different developmental stages. The acid-dissolution rates were determined at each window by using 1.4 M sodium acetate-hydrochloric acid buffer (pH 2.3). The rate of enamel dissolution was highest in the matrix-formation stage and dropped sharply in a step-wise fashion towards the stages of secondary mineralization and iron deposition. The dissolution rate in the maturation stage decreased significantly with increasing intake of fluoride. However, in the pigmented enamel, the opposite occurred. The iron pigmentation or the porosity in this region of fluorosed enamel might be responsible for the change in the dissolution rate of the pigmented enamel.