[The mechanics analysis of orthodontic treatment for the impacted inversed upper central incisor].

PURPOSE: To study the treatment on the impacted inversed upper teeth by orthodontic traction. METHODS: Nineteen impacted curved upper teeth were treated with surgical exposure and orthodontic traction after X-ray location and tooth space expansion. RESULTS: Among the 19 impacted teeth, thirteen teeth were successfully treated, four were approximately erupted, two were failed. The average eruption time of the 19 impacted teeth was 6.5 months(3-12 months). All the teeth had vital pulp without root absorption or conglutination. There was labial gingival regression with 2mm and 4mm in 2 teeth, respectively. Marginal bone loss of 1.0 mm was found in one tooth. In 1 case, the tooth couldn't be moved into alignment, and light-cured or porcelain crown treatment was suggested. In 1 case, the tooth couldn't be moved into alignment due to the severely curved root, and then was extracted. In 1 case, the tooth erupted after traction for 3 months, but the patient rejected the treatment. All the other teeth moved into alignment. CONCLUSIONS: Exact location, appropriate traction force and direction decide the movement of impacted teeth.

[Epidemic investigation on 3 to 6 years children's bruxism in Shanghai.].

PURPOSE: The present investigation analyzed the states of children bruxism in Shanghai, aiming for early diagnosis and early treatments. METHODS: The investigation was conducted through questionnaising 779 3-to-6-years-old children's parents. The data were processed using Chi square test. RESULTS: (1)The prevalence of children bruxism in Shanghai was about 38.4%; (2)151 males (40.6%) and 148 females (36.4%) had bruxism, which indicated no statistic difference in two genders(X2=1.47, P>0.05);(3)There seemed to exist hereditary difference between children with or without bruxism(X2=102.98, P<0.01). CONCLUSION: There is a high bruxism prevalence among children aged from 3 to 6 years in Shanghai, which should be concerned about by the healthy care workers in order to make early diagnosis and treatment.

[The influence of occlusion on the incidence of bruxism in 779 children in Shanghai].

PURPOSE: To explore the influence of occlusion on the incidence of bruxism in children. METHODS: The incidence of bruxism in children was investigated from the questionnaire of 779 children's parents. The occlusion of these children was checked by professionals. The influence of the occlusion on the incidence of bruxism in children was analysed. Chi-square test was used for statistical analysis. RESULTS: The occlusion of children with bruxism and children without bruxism had no significant difference (P>0.05). The incidence of bruxism did not increase in the children with mixed dentition(P>0.05). CONCLUSION: The occlusion does not affect the incidence of bruxism in children. The mixed dentition does not increase the incidence of bruxism in children.