[Effect of different cleaning methods on bond strength and surface wettability of high translucency zirconia].

PURPOSE: To study the effect of different cleaning methods on the shear bond strength of self-adhesive resin cement to saliva-contaminated high translucency zirconia and surface wettability. METHODS: Eighty zirconia specimens were randomly divided into 5 groups (n=16), i.e., control group(not contaminated), 75% ethanol group,cleaning paste group,airborne-particle abrasion group, and atmospheric pressure cold plasma group. The contact angles was measured, shear bond strength were examined, and fracture types were determined. SPSS 26.0 software package was used for statistical analysis of the data. RESULTS: The atmospheric pressure cold plasma group produced the lowest contact angle(P＜0.05). The shear bond strength of the airborne-particle abrasion group, the cleaning paste group and the atmospheric pressure cold plasma group respectively were similar to the control group without significant difference(P＞0.05), while those were significantly higher than 75% ethanol group(P＜0.05). The mixed fracture mode of the atmospheric pressure cold plasma group evidently increased. CONCLUSIONS: Airborne-particle abrasion, cleaning paste and atmospheric pressure cold plasma overcome the effects of saliva contamination, producing the shear bond strength to zirconia similar to the control group. The atmospheric pressure cold plasma improves hydrophilicity of high translucency zirconia significantly.

[Prevalence of malocclusion among 5 387 12- to 14-year-old adolescents in Jiangxi province, China: an epidemiological study].

OBJECTIVE: We provided baseline data for oral public health through epidemiological surveys to investigate the prevalence of malocclusion and orthodontic treatment proportion in 12- to 14-year-old adolescents in Jiangxi province, China. METHODS: Multi-stage random cluster sampling was used. A total of 5 387 12- to 14-year-old adolescents were examined by three professional dentists according to Angle's classification of malocclusion. The subjects were recruited from 30 secondary schools in five counties in Jiangxi Province. Results were statistically analyzed by SPSS19.0. RESULTS: The prevalence of malocclusion was 79.67% among adolescents aged 12-14 years in Jiangxi province. The composition ratios of ClassⅠ, Class Ⅱ Division 1, Class Ⅱ Division 2, and Class Ⅲ malocclusion were 30.96%, 16.36%, 12.78%, and 19.13% respectively. ClassⅠmalocclusion had the highest composition ratio, and the most common clinical manifestation of malocclusion was dentition crowding with a prevalence of 91.30%. The prevalence rate of malocclusion was higher in boys than in girls at 81.16% and 78.21%, respectively (P<0.05). This condition had different prevalence rates in Nanchang, Yichun, Jiujiang, Shangrao, and Ganzhou (P<0.05) with the highest in Nanchang and lowest in Ganzhou. Malocclusion was related to caries, and its prevalence rate was higher in patients with caries than in those without caries (P<0.05). The orthodontic rate of malocclusion was 2.63%, and the value was higher for girls than that for boys (P<0.05). The rate of orthodontic in urban areas was higher than that in rural areas (P<0.05). CONCLUSIONS: Compared with local and international findings on malocclusion of adolescents, high prevalence and low orthodontic rate were found in Jiangxi province. Strengthening the combination of prevention and treatment is important for the physical and mental health of adolescents. We should actively conduct oral health education, popularize the knowledge of malocclusion, and actively treat caries.

[Status and strategies of oral health service demand and medical treatment utilization among 3- to 5-year-old preschool children in Jiangxi province].

OBJECTIVE: This study aimed to investigate the oral health service needs and dental treatment among 3-year-old to 5-year-old preschool children in Jiangxi province and provide data to support the development of relevant oral health policies, enhance the oral health service utilization and visit rate, and optimize oral manpower and service resources. METHODS: A total of 2 880 preschool children were selected via stratified cluster sampling. Dental examination methods and criteria according to the fourth national oral health epidemiological survey were adopted. Excel 2007 and SPSS 19.0 softwares were used for statistics analysis. Chi-square test and logistic regression analysis were performed. RESULTS: The caries prevalence was 49.13% (1 415/2 880) among the 2 880 cases of 3-
year-old to 5-year-old preschool children in Jiangxi province, approximately 53.37% (1 537/2 880) of which possessed oral health service needs. The parents of younger children assessed the oral situation better in older age than in their younger years (P<0.05), which was better in urban children than in rural children (P<0.05). The visiting rate of all the respondents was 12.33% (355/2 880), while the visiting rate of children with oral diseases was 17.31% (266/1 537). The top three reasons why patients did not visit the dentist were as follows: children's teeth have no problem, the teeth damage in teeth was considerably minimal, and primary teeth would be replaced without the need for treatment. The influencing factors included lower visiting rate in females than in males (OR=0.499, 95%CI: 0.411-0.606) and lower visiting rates in rural areas than in urban areas (OR=0.428, 95%CI: 0.353-0.519). Subjects with poor oral health and high oral knowledge scores possessed high dental service visit rates. CONCLUSIONS: The prevalence of caries in 3-year-old to 5-year-old preschool children in Jiangxi province is at a lower level than that in the national level. The proportion of the population actively seeking medical services is low, and their main purpose of treatment is to treat rather than prevention. Oral health education should be strengthened, and it should be incorporated to the contents of the kindergarten teacher training program to improve residents' awareness regarding children's oral health.

[Clinical evaluation of denture adhesive combined with oral wetting spray on satisfaction of complete denture in xerostomia patients].

PURPOSE: The purpose of this study is to investigate the effect of denture adhesive and oral wetting spray on the satisfaction of wearing complete denture in xerostomia patients. METHODS: Ten edentulous patients who suffered from deficient residual alveolar ridge and xerostomia with poor retention and stability of complete dentures or mandibular complete dentures were employed to assess the differences of satisfaction after use of denture adhesive in their dry oral cavity for 1 week, and use of denture adhesive combined with oral wetting spray for 1 month, 3 months and 6 months by using satisfaction questionnaire. The statistical analysis was carried out with SPSS17.0 software package. RESULTS: Six months after the use of denture adhesive combined with oral wetting spray, the satisfaction of complete denture was significantly improved in respects of general satisfaction, retention of mandible denture, comfort and mastication improvement than that before application (P<0.05). But 1 week after the use of denture adhesive alone, the satisfaction of comfort reduced than that before application (P<0.05). CONCLUSIONS: Denture adhesive combined with oral wetting spray can be used to improve the satisfaction of xerostomia patients treated with complete denture who suffered from deficient residual alveolar ridge.

[Clinical evaluation of indirect post core by two different impression methods].

OBJECTIVE: To evaluate the clinical effect of indirect cast post core by two different impression methods between silicone rubber impression and agar/alginate combination impression. METHODS: 389 massive destruction teeth after root canal therapy were randomly divided into two groups (group A and group B). The teeth of group A was treated by silicone rubber impression material for making indirect post core impression. The teeth of group B was treated by agar/alginate combination impression for making indirect post core impression. The effect of two different impression methods was evaluated. RESULTS: The success rate of making indirect post core impression by silicone rubber impression method was higher than that of making impression by agar/alginate combination impression method. Significant difference was found in making indirect post core impression between premolars and molars by two different impression methods (P<0.05), while there was no significant difference in making indirect post core impression of anterior teeth by two different impression methods (P>0.05). CONCLUSION: The clinical effect of making indirect post core impression by silicone rubber impression method is better than that of making impression by agar/alginate combination impression method.

[In vitro comparison of the retention adjustment of telescopic crowns].

PURPOSE: The objective of the present in vitro study is to explore the retention readjustment measure of the non-precious metal telescopic crown. METHODS: Twenty-seven standard size dies were divided into three groups randomly, conventional Co-Cr alloy group, Co-Cr alloy slit telescopic crown group and Au-Pd alloy group. Each group had 9 dies. The retentive force of telescopic crowns was investigated after repeated insertion/separation tests. Statistical analysis was performed using SPSS12.0 software package for one-way ANOVA. RESULTS: The retention of Au-Pd crown group and Co-Cr alloy slit telescopic crown was significantly larger than that of conventional Co-Cr alloy crown group. The maximal retention of Co-Cr alloy slit of the telescopic crown group was significantly larger than Au-Pd crown group. Compared with Co-Cr alloy slit telescopic crown group, the retention of all procedures in Au-Pd crown group had statistical significance except the retention of 800 procedures. CONCLUSIONS: The retention of slit telescopic crown is similar to precious mental telescopic crown. Slit telescopic crown can compensate the retention deficient of none-precious metal telescopic crown. Supported by Science and Technology Research Project of Bureau of Health of Jiangxi Province (Grant No.060436).