The prevalence of pre-eruptive dentin radiolucencies in the permanent dentition

Although intracoronal radiolucencies in radiographs of unerupted teeth have been reported for several decades, the prevalence of this condition remains unknown. This study determined the prevalence and associated dental conditions of permanent teeth showing pre-eruptive dentin radiolucencies in bite-wing radiographs of school children attending two school dental therapy training centers.

There were 1959 subjects (934 males and 1025 females), each providing a set of bite-wing radiographs which showed the crowns of unerupted permanent teeth. The mean age of the children at radiographic exposure was 7.8 +/- 1.79 years of age.

126 (6%) of subjects had radiolucencies in the crowns of pre-eruptive permanent teeth. Of the 9919 teeth viewed on the radiographs, 163 (2%) were affected. There were no significant racial and gender differences in the prevalence of the defects. Of the 126 subjects with dentin radiolucencies, 93 (74%) had only 1 affected tooth compared with 31 (25%) who had two teeth affected, and 2 (2%) who had 3 affected teeth.

Within each tooth type, the highest tooth prevalence was found in the mandibular first molar (4%), followed by the mandibular first premolar (2%), the mandibular second molar (1%), mandibular second premolar (1%), maxillary first molar (1%), maxillary first premolar (1%), and maxillary second premolar (0.2%). In addition, the group with dentin radiolucencies had a high prevalence of ectopically-positioned teeth of 14% compared with only 2% in the group without the defect, suggesting that ectopic position may predispose a tooth to pre-eruptive radiolucent defects. Other common developmental and acquired dental conditions were also examined, but no significant differences were noted between groups with and without the pre-eruptive dentin radiolucencies.