Biomedical subjects
Publications and source records attributed to L H McAllan.
Dens evaginatus is a developmental anomaly primarily in people of Mongoloid origin. The premolar teeth are more often affected, although molars, canines and incisors have been recorded as affected. The anomaly consists of a tubercle of enamel-covered dentine, containing an extension of pulpal tissue. Early attrition or fracture of the tubercle can result in pulpal necrosis in immature teeth.
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The effect of individual chairside instruction and motivation on children using either manual or electric toothbrushes was investigated. From 123 children aged 9-15 years attending the Children's Department, Eastman Dental Hospital, four groups were constructed. Group 1 acted as the control, Groups 2 and 3 used manual toothbrushes and received instruction and motivation, and Group 4 used electric toothbrushes (Touch Tronic, Teledyne Aqua Tec) and also received instruction and motivation. For all children, modified Löe and Silness' Gingival and Plaque Indices were scored, a disclosing agent applied and a prophylaxis completed. Children in Groups 2, 3 and 4 were additionally shown the disclosed plaque, and its importance was discussed. Their attempts to "get the stain off" were checked and their own brushing techniques modified. Re-examinations took place after 1 and 3 months. To estimate the reliability of the diagnosis, 172 of the 344 examinations were repeated by a second operator. The overall coefficient of correlation (between operators) was 0.8. In the control group no detectable improvement in the gingival health or oral cleanliness occurred over the 3-month study period. However, both gingival and plaque scores decreased significantly, by 35-50%, in all instructed and motivated groups within 1 month and this improvement was still observable 2 months later. There were no significant differences in improvement between motivated children using manual or electric toothbrushes.
PURPOSE: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.
PURPOSE: This investigation stemmed from preliminary clinical observations from a school dental clinic, which suggested that a proportion of clinically undetected, radiolucent lesions on radiographs may originate as pre-eruptive intracoronal dentin defects. This study investigated the prevalence of such defects in orthopantomograms from a group of children and young adults. METHODS: A total of 1281 orthopantomograms with 11,767 unerupted permanent teeth were examined. RESULTS: The prevalence of intracoronal dentin defects was 3% by subjects, and 0.5% by teeth; the highest prevalence being noted in the maxillary and mandibular first permanent molars. Most of the lesions occurred singly, and nearly half had extended to greater than two-thirds the width of dentin thickness. Ectopic positioning was significantly associated with this lesion. CONCLUSIONS: Pre-eruptive intracoronal dentin defects occur at a significant prevalence rate. Increased awareness of this entity may improve diagnosis and allow early treatment.
PURPOSE: This prospective, cross-sectional study examined the sensitivity and specificity of clinical assessment compared to bitewing radiographs in the detection of occlusal dentin caries in permanent molars. METHODS: Subjects were 481 children aged 5-12 years from a school-based dental clinic. Occlusal surfaces of 1929, sealed and unsealed first and second permanent molars were examined clinically and scored using specific criteria. Teeth with any type of restorations or proximal caries, including preventive resin restorations, were excluded from the study. Bitewing radiographs were exposed within 4 weeks of clinical examination and were assessed for dentin radiolucencies beneath the occlusal surface. The results of the clinical examinations were correlated with those of bitewing radiographs. Information provided by the parents on history forms, including systemic fluoride exposure, was also noted. RESULTS: Of the 1833 teeth scored as clinically sound in the study, only 72 (4%) demonstrated a dentin radiolucency on bitewings, and 1761 (96%) were scored as sound. The sensitivity of the clinical examination was determined to be 0.96. In the teeth clinically scored as showing dentin caries, only 56/96 (58%) were found to have dentin radiolucencies on the radiographs. The specificity of the technique was determined to be 0.58. A positive history of a medical condition, or fluoride exposure, in the forms of toothpaste use, or water fluoridation did not affect the examination results. CONCLUSIONS: Clinical examination of cleaned and dried, sealed, and unsealed teeth has a sensitivity of 0.96 and a specificity of 0.58 in the detection of dentin radiolucencies in bitewing radiographs. Dentin radiolucencies beneath clinically sound occlusal surfaces are not significantly associated with gender, medical conditions or fluoride.