The dental health of 45 children who had been placed on long term evaluation after chemotherapy treatment for malignancies was examined in this study. All children had received cytotoxic drugs during the period of tooth formation. It was found that they had more filled or diseased permanent teeth than control children. Their current caries activity as indicated by initial white spot lesions was also higher. Forty-three of the children showed evidence of disturbed amelogenesis. This had resulted in aesthetically displeasing grooves, pits and discoloration. Twenty-three of the children were counseled on the possibility of cosmetic dentistry. Delayed eruption and shortened, malformed roots were also found on several patients. It was concluded that these patients constitute a high risk dental care group.

To gain greater understanding of the role of Streptococcus mutans and Veillonella in the caries process, studies of both aerobically and anaerobically grown plaques of S. mutans C67-1 and V. alcalescens V-1 on human enamel slabs were carried out in an artificial mouth. Plaque development, acid production, and demineralization were measured. Early plaque development of monobacterial and mixed bacterial plaques started from randomly adhering cells on day 1 to confluent multilayered microcolonies on day 4. Differences were observed in viable cell counts, total cell mass, and in acid production. In most cases CFU, DNA and acid production were higher in the mixed bacterial plaque, especially in the anaerobic mixed plaque. Lactic acid was the predominant acid in all cases following the supply of sucrose to the plaque. No decisive role could be found for acetic, formic, and propionic acid. No inhibition of demineralization was observed in the enamel slabs inoculated with both aerobic and anaerobic mixed plaques. Demineralization ranged from the more classical picture of lesion development in the aerobic monobacterial plaque-treated samples to an aggressive etching of the enamel surface in the anaerobically mixed treated slabs.

The accuracy and reproducability of hardness measurements have been investigated in this study. Sound and demineralized enamel were used as the main test materials. The reproducability of hardness measurements on artificial white spot lesions produced by a hydroxyethyl cellulose/lactic acid demineralizing solution was also investigated on embedded cross-sections. The operator error was found to be less than 5% when reading both steel and enamel indentations. The maximum hardness of the surface layer and the minimum hardness of the subsurface lesion were measured in three positions in each of 10 artificial white spot lesions. An analysis of the results showed that: (a) the hardness values at the same distance from the surface but in different areas of the same lesion were very similar; (b) hardness values between lesions were also very even; (c) the drop in hardness after demineralization was related to the initial hardness of the enamel.

Twelve duplicated bitewing radiographs of clinical quality were viewed under controlled conditions by 42 dentists in a teaching department. The dentists noted surfaces with initial caries or with caries in need of treatment. The radiographs were rediagnosed by 20% of the dentists to determine inter- and intra examiner reliability. A norm for the validity of lesion presence in enamel or dentin was applied. The variation in surfaces indicated for treatment is illustrated by: mean 40, s.d. 16, min. 13 and max. 89 for the 42. The mean proportion of true positive filling decisions in percentages was 67, s.d. 18, the mean proportion of false positive filling decisions was 22, s.d. 22. A large individual variation was found in this study. The dental teachers saw less caries present than the norm but some indicated more fillings needed than dentin caries present. It is suggested that care in the educational process should be given to developing appropriate caries treatment criteria. Factors conducive to preventively orientated treatment decisions in the clinical situation need further attention.

In a double-blind crossover study the remineralizing effects of the combinations: placebo toothpaste, placebo gel; amine fluoride toothpaste, placebo gel; amine fluoride toothpaste, 0.25% F^–– amine fluoride gel and amine fluoride toothpaste, 0.4% F^–– amine fluoride gel were investigated in vivo. Artificially demineralized flattened enamel slabs were placed in the buccal flanges of partial dentures. It was found during the 3-week experimental periods that there was a significantly higher increase in remineralization in the 2 fluoride gel groups. This occurred in both the surface layer and subsurface lesion and resulted in a significant decrease in lesion depth and increase in hardness. It is suggested that the weekly use of these gels should be considered in patients with early enamel lesions if they are formed during, or fail to remineralize under, a normal preventive regime.