Assessment of enamel opacities in children in Sri Lanka and England using a photographic method.

Colour photographs were taken of the labial surface of both maxillary central incisor teeth of children aged 12 years, living in Sri Lanka and England. In each country, children were included who lived in communities receiving drinking water containing 0.1, 0.5 and 1.0 ppm F, and within these communities children were classed as high or low socio-economic (SE) status. The photographs were examined 'blind' by two examiners independently. These pertained to 670 children, 332 in Sri Lanka and 338 in England. The index of Developmental Defects of Enamel (DDE) was used, as modified by Clarkson and O'Mullane (1989), to measure type and extent of opacity. Intra- and inter-examiner agreement was substantial. Prevalence of opacities ranged from about a quarter of teeth in the 0.1 ppm F area in Sri Lanka to over 60 per cent of teeth in the high socio-economic group in the 1.0 ppm F area in England. Higher prevalences of opacities were recorded in: (1) the high SE group than the low SE group in the 1.0 ppm F area in England, (2) the 1.0 ppm F area than in the 0.1 ppm F area in both countries, (3) in Sri Lanka than in England in low SE groups in the 1.0 ppm F areas. The greatest differences occurred in diffuse opacities. When these data were compared with results of clinical examinations of these same tooth-surfaces by one examiner (n = 506) more teeth were graded 'normal' clinically and more teeth graded as having opacities photographically. Both demarcated and diffuse opacities were scored more frequently from photographs than clinically in both countries.