Seow W K, Wan A, McAllan L H
University of Queensland School of Dentistry, Brisbane, Australia.
Pediatr Dent. 1999 Jan-Feb;21(1):26-33.
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.
尽管在未萌出牙的X线片上发现牙冠内透射区已有数十年报道，但这种情况的患病率仍不清楚。本研究确定了在两个学校牙科治疗培训中心接受检查的学童的咬合翼片上显示萌出前牙本质透射区的恒牙的患病率及相关牙齿情况。
共有1959名受试者（934名男性和1025名女性），每人提供一组显示未萌出恒牙牙冠的咬合翼片。拍摄X线片时儿童的平均年龄为7.8±1.79岁。
126名（6%）受试者的萌出前恒牙牙冠有透射区。在X线片上观察的9919颗牙齿中，163颗（2%）受到影响。这些缺陷的患病率在种族和性别上无显著差异。在126名有牙本质透射区的受试者中，93名（74%）仅有1颗患牙，31名（25%）有2颗患牙，2名（2%）有3颗患牙。
在每种牙型中，下颌第一磨牙的患病率最高（4%），其次是下颌第一前磨牙（2%）、下颌第二磨牙（1%）、下颌第二前磨牙（1%）、上颌第一磨牙（1%）、上颌第一前磨牙（1%）和上颌第二前磨牙（0.2%）。此外，有牙本质透射区的组中异位牙的患病率为14%，而无此缺陷的组中仅为2%，这表明异位位置可能使牙齿易患萌出前透射性缺陷。还检查了其他常见的发育性和后天性牙齿情况，但有和没有萌出前牙本质透射区的组之间未发现显著差异。
