[Study of the root position of palatally malposed maxillary lateral incisor based on cone-beam CT images].

PURPOSE: The goal of this investigation was to measure and analyze the root position of palatally malposed maxillary lateral incisor based on cone-beam CT(CBCT)images, in order to provide references for orthodontists to move this kind of teeth scientifically. METHODS: CBCT data from 200 patients meeting the selection criteria with palatally malposed maxillary lateral incisor were investigated in this study. The root was divided into eight equal parts by length, then T1 to T8 were orderly pointed from root apex to alveolar ridge crest. The labial and palatal bone thickness at each point was measured; meanwhile, the angle between the long axis of the tooth and that of the alveolar bone was measured.The data was analyzed using SPSS 19.0 software package. RESULTS: The mean labial bone thicknesses at all researched points were less than 1.00 mm, except for point T1,T7 and T8. The mean labial bone thicknesses at point T3, T4 and T5 were the thinnest, which were all less than 0.5 mm(P<0.05). The mean thicknesses of labial bone gradually increased from T4 to T8(P<0.05). The mean palatal bone thicknesses were all more than 1.00 mm at the eight points,the mean thicknesses of palatal bone gradually increased from T8 to T1(P<0.05). All the angulations between the long axes of teeth and those of the alveolar bone were negative, indicating the root was close to the labial alveolar wall. The average angulation was minus 31.06 degrees. CONCLUSIONS: Results suggest that the root of palatally malposed maxillary lateral incisor is close to the labial wall of the alveolar bone, its labial alveolar bone is frequently quite thin or even deficient, especially in the zone between 1/4 root length to the root apex and the mid-root. If we move the palatally malposed maxillary lateral incisor labially, it is better to choose tipping movement, instead of bodily movement, in order to avoid serious bone fenestration and dehiscence or root absorption.

[Early childhood caries and its related risk factors in 1 296 children aged 3 to 5 years old in Shanghai].

PURPOSE: To investigate the prevelence of early childhood caries (ECC) and its related risk factors in children aged 3 to 5 years old in Shanghai. METHODS: According to the requirements of the Fourth National Epidemiological Survey of Oral Health, multistage, stratified, equal capacity and simple random sampling method was performed. A total of 1 296 children aged 3, 4 and 5 years old in 12 kindergartens in Shanghai were selected to calculate the prevalence and the mean dmft(decayed-missing-filled tooth). Their parents were surveyed with questionnaire on oral hygiene habit and consciousness of oral health and related factors. Statistical analysis were performed using SPSS 21.0 software package. RESULTS: The prevalence of ECC were 58.07% in children aged 3 to 5 years old in Shanghai, with dmft index of 2.99 in average. There were significant differences in the mean dmft and the prevalence between male and female and among different age groups(P<0.05). In multivariate logistic regression analysis, more frequent sweet drinks, eating sweets before sleep, less daily tooth brushing, starting tooth brushing after 2 years old and low level of parents' education and oral health knowledge were risk factors for dental caries. CONCLUSIONS: The prevalence of ECC in children aged 3 to 5 years old in Shanghai is severe. There is an urgent need for implementation of a systematic education on diet habit and oral health behavior, and the parental education on oral hygiene needs to be further improved.

[Status of tooth loss, prosthodontic treatment and oral health-related quality of life of Shanghai elderly people].

PURPOSE: The aim of the present study was to investigate oral health status of the elderly in Shanghai using Eichner index dental classification system, and to discuss the relations between tooth loss, prosthodontic treatment and the impact on oral health-related quality of life(OHRQoL). METHODS: A total of 747 subjects aging 65-74 years old were selected by multistage stratified cluster sampling method. Clinical examination and questionnaires of the Fourth National Oral Health Survey of China were used for the study, and data of tooth loss, OHRQoL were analyzed using non-parametric test and binary logistic regression with SPSS 19.0 software package. RESULTS: 79.1% of the subjects had problem of missing teeth, while 35% of them never received any kind of dental prosthesis. Grouping by the Eichner index, only A1, A2 and C3 group were scored above the average, while group B had the lowest general oral health assessment index(GOHAI) score. The scores of GOHAI were significantly correlated to dental prosthodontic treatment, overall health status and Eichner index(P<0.05). Except for group C2 due to the small sample size, the scores of GOHAI in most of the untreated subjects were lower than those who had prosthesis. Among the subjects with missing teeth but without prosthesis, 81.2% of the subjects thought they had no problem with their teeth or the problem did not matter. CONCLUSIONS: Tooth loss is a serious problem among the elderly in Shanghai, but only a few of them have received dental prosthodontic treatment. The OHRQoL of the elderly is related to tooth loss, dental prosthodontic treatment and overall health. Oral health education should be strengthened for the elderly people with missing teeth, to replace their missing teeth timely and improve their quality of life.

[Epidemiological investigation and analysis of risk factor of tooth loss in older people aging 65-74 years in Shanghai].

PURPOSE: To investigate tooth loss status and associated risk factors in older adults aging 65-74 years in Shanghai. METHODS: Seven hundred and seventy-six participants aging between 65-74 years were randomly selected in a cross-sectional study according to the requirements of the fourth national oral health epidemiological investigation of China. Data was obtained via questionnaires and clinical examination. Non-parametric analysis was performed to compare the numbers of lost teeth and molars between groups. Logistic regression analysis was performed to assess risk factors for tooth loss with SPSS 21.0 software package. RESULTS: The average numbers of lost teeth and lost molars were 5.94 and 2.59, respectively. 42.3% subjects had periodontal pockets and 83.0% had at least 4 mm attachment loss. Males lost more teeth and molars than females (P<0.05). Smoking was a risk factor for maintaining functional dentition, especially when the smoking amount reached 6/d (odds ratio=1.88, 95% confidence interval: 1.231-2.872, P<0.01). Less than 6 years schooling and occupation requiring hard physical labor were also important risk factors for tooth loss. CONCLUSIONS: Gender, oral hygiene habits, smoking, educational level and occupation are important risk factors for tooth loss in 65-74 year old adults in Shanghai.