Extraction of 'nylon' teeth and associated abnormalities in Tanzanian children.

The aim of this study is to determine the prevalence of extraction of 'nylon' teeth and its long term adverse effects on the permanent dentition of Tanzanians. A total of 1890 subjects, aged between 3 and 5 years, and 1377 subjects aged between 12 and 19 years, in different parts of the country were examined. The prevalence of missing teeth in the primary dentition due to 'nylon' teeth practice ranged from 0% to 16.9%, with a weighted mean of 9.5%. Canines were the most involved teeth, accounting for 95% of all missing teeth. Mutilated permanent teeth, a result of traditional extraction of deciduous tooth germs, were observed only in Singida district in 8% of the examined subjects. 22.8% of these mutilations presented as malformations, while the remaining 77.2% presented as missing teeth. Most missing teeth and all the malformed teeth were seen in the mandible. The mandibular canines were the most affected, followed by the mandibular lateral incisors. It is suggested that 'nylon' teeth practice in Tanzania may be a recent invention rather than a traditional tribe related custom. The precariously high prevalence of 'nylon' teeth practice in Tanzania, and the people's perception of this malpractice, requires that particular attention be paid to this issue during oral health educational programmes in the affected communities.