Relationships between patient characteristics and reasons for tooth extraction in Japan.

Objectives: The purpose of this study was to examine the relationships between patient characteristics and reasons for extraction of permanent teeth. Methods: 5,131 dentists were selected from the list of the membership directory of the Japan Dental Association by systematic random selection. The dentists were asked to record the reason for each extraction of permanent teeth during a period from February 1 to 7, 2005. Reasons for tooth extraction were assigned to five groups: caries, fracture of teeth weakened by caries or endodontics, periodontal diseases, orthodontics and other reasons. We used cross tabulation and multiple logistic regression analysis to estimate the relationships between patient characteristics and reasons for tooth extraction. Results: 2,001 dentists (response rate of 39.0%) returned the forms, and complete information on 7,333 patients was obtained. A total of 3,196 (43.6%) patients underwent tooth extraction due to caries and its sequela, and 2,721 (37.1%) patients underwent tooth extraction due to periodontal disease. Multiple logistic regression analysis showed that denture wearers were more likely to undergo tooth extraction due to periodontal disease in all age groups (p<0.05). Males tended to undergo tooth extraction due to periodontal disease than did females in all age groups (p<0.05) except for age group 30-49. Subjects with 19 or less teeth were more likely to undergo tooth extraction due to periodontal disease in the age groups 30-49 (p<0.001) and 50-69 (p<0.001). In the age group of 50 years or older, female (p<0.01 ) and the possession of 20 or more natural teeth (p<0.05) were related to caries extraction. However, there was no clear relationship between caries extraction and patient characteristics under 50 years old. Conclusion: There was a significant relationship between denture wearing and periodontal extraction. In the middle aged population, patients with 19 or less teeth lost their teeth mainly due to periodontal disease.