The object of this study was to investigate the prevalence rate and risk factors of dental erosion for the purpose of providing basic data to an occupational dental health program. Recruited as study subjects were 866 workers in one galvanizing and four battery manufacture factories from March to September, 2000. A questionnaire was administered to workers for information about sociodemographic status, gastric symptoms, dietary habits, medication and symptoms of the body, Clinical oral examinations assessed presence or absence of dental erosion using a classification by Cate. The prevalence rate of dental erosion, the mean number of teeth eroded and eroded teeth(weighted) were calculated. These variables were compared among industry type, factories and location. Logistic regression and multiple regression were analysed for statistical analysis. The results were as follows
1. The prevalence rates of dental erosion were Grade 1(25.5%), Grade 2(2.9%), Grade 3(4.5%), Grade
4(1.4%), Grade 5(0.4%) and total(34.7%) in workers exposed to acid. The number of eroded teeth was 1.44±2.59 and eroded teeth(weighted) was 2.28±5.62.
2. The dental erosion was higher in anterior and upper teeth than in posterior and lower teeth in workers exposed to acid(p (0.05). The dental erosion was higher in upper teeth than in lower teeth in non
exposed exposed workers(p (0.05).
3. In workers exposed to acid, there were significant differences in the prevalence of dental erosion,
eroded teeth and eroded teeth(weighted) among factories(p (0. 01).
4. In workers exposed to acid, there were significant differences in the eroded teeth and eroded teeth (weighted) between the two industries (p (0.01).
5. The risk factors for the prevalence of dental erosion were acid(odds ratio: 3.48), service year(odds ratio:
1.33) and frequency of tooth brushing by rolling method(odds ratio: 0.73).
6. The risk factors for the number of eroded teeth were acid(B: 0.99), age(B: 0.30) and brittle teeth(B: 1.29), and for the number of eroded teeth(weighted) were acid(B: 1.83), age(B: 0.67) and brittle teeth(B: 1.42).
7. When age and service year were changed as dummy variables, the risk factors for the prevalence of dental erosion were acid(odds ratio: 4.32), service years(5-10years) (odds ratio: 1.33), age(4049years)(odds ratio: 1.74), age( (30years) (odds ratio: 0.50) and frequency of tooth brushing(odds ratio: 0.75).
8. When age and service year were changed as dummy variables, the risk factors for eroded teeth were acid(B: 0.98), service years(5-10years)(B: 0.73), age(40-49years)(B: 0.82) and brittle teeth(B: 1.21) and for eroded teeth(weighted) were acid(B: 1.87), age(40-49years)(B: 1.43) and brittle teeth(B: 1.46).
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