Preschoolers' dental caries experience and its trend over 20 years in a North-East Italian Health District.

AIM To describe dental caries occurrence among preschool children in a Health District in the North-East of Italy by age, gender and immigrant background; 2) to plot a trend of primary dentition dental caries over a 20 year time span. STUDY DESIGN Observational cross-sectional survey. METHODS 41 out of 88 kindergartens were randomly selected, originating a sample of 3470 preschoolers out of 7,061 overall school attenders. Dentinal caries occurrence was evaluated by 2 calibrated examiners at school on 2,524 3-5-year-olds from October 2004 to June 2005. The participants were divided into 2 subgroups depending on the country of origin of their mothers: non-western (IG or immigrant group) and western (WG). Two previous surveys performed in the same area were used to plot a trend over a 20 year period. STATISTICS Comparisons between groups were made using the Pearson chi-squared test and caries risk estimation was established by logistic regression analysis to assess the influence of sex, age and ethnicity (independent variables) on caries experience (dependent variable). Risk was summarised as odds ratio plus 95% CI. RESULTS Prevalence (%) and severity (mean dmft +/- SD) increased by age (15% - 0.6 +/- 1.9 at 3 years of age; 25% - 1.1 +/- 2.6 at 4; 32% - 1.3 +/- 2.7 at 5) and were significantly different (p<0.01) between the two groups: 23% (WG) vs 54% (IG) and 0.9 +/- 2.2. (WG) vs 3.4 +/- 4.3. The level of untreated caries was high: 88.9% in WG vs 97.1% in IG. From 1984 to 2004 prevalence and severity of dental caries declined at all examined ages. CONCLUSION The current dental scores in preschoolers are low and similar to those reported in other Western European countries. These good scores have been achieved through a strong decline occurred over the last two decades. As regards the Italian recent social phenomenon of immigration, nowadays being an immigrant child is a strong determinant of dental caries.