Survival analysis of crown margin repair: A retrospective study in a dental school setting

BackgroundRepairing crowns with defective margins is minimally invasive and cost-effective compared with replacement. The authors’ objectives were to examine the survival trajectory of crown margin repairs and to determine the factors associated with survival.MethodsRecords of adult patients from January 2008 through August 2019 were reviewed for crown margin repairs completed at University of Iowa College of Dentistry. A total of 1,002 crown margin repairs were found. Each repair was followed through the end of study in 2019 or until an event (for example, additional repair, endodontic treatment, crown replacement, or extraction). A Cox proportional hazards model was used to study the relationship between selected covariates and time to event.ResultsDuring the follow-up period, 32.8% of the repairs needed reintervention. In the final model, repair material was the only significant covariate. No difference was found between the survival of repairs done with resin-modified glass ionomer and amalgam. However, the repairs done with resin-based composite and conventional glass ionomer were more likely (1.5 times: 95% CI, 1.02 to 2.10 times; and 2 times: 95% CI, 1.40 to 2.73 times, respectively) to need reintervention than were those done with amalgam.ConclusionsMedian survival time of crown margin repairs was 5.1 years (95% CI, 4.48 to 5.72 years). Median survival times for amalgam, resin-modified glass ionomer, resin-based composite, and glass ionomer repair materials were 5.7 years (95% CI, 4.80 to 6.25 years), 5.3 years (95% CI, 4.73 to 6.34 years), 3.2 years (95% CI, 2.51 to 6.19 years), and 3.0 years (95% CI, 2.53 to 3.62 years), respectively.Practical ImplicationsWhen considering crown margin repairs, resin-modified glass ionomer or amalgam is preferable to resin-based composite or glass ionomer.     

26所基层民营口腔诊所医务人员手卫生现况调查

 目的 调查十堰市区基层民营口腔诊所医务人员手卫生现况。方法 2019年9—11月采用便利抽样法对十堰市区民营口腔诊所医务人员手卫生现况进行隐蔽式调查,分析并比较不同岗位类别医务人员的手卫生依从率及正确率。结果 共调查民营口腔诊所26所,设有专用洗手设施的仅17所(占65.38%),配有快速手消毒剂的12所(46.15%)。隐蔽式观察102名医务人员,观察有效手卫生时机2 183次,医务人员实际执行572次,手卫生依从率26.20%,正确率25.52%(146次)。不同岗位类别医务人员的手卫生依从率、正确率比较,差异均有统计学意义(均P＜0.001)。护士的手卫生依从率(30.80%)、正确率(31.85%)较其他岗位人员高。医务人员在接触患者体液后的依从率(76.24%)和正确率(40.26%)较其他手卫生时刻高,接触患者前后的手卫生依从率最低,仅为15.38%、24.72%。医务人员不同手卫生时刻的依从率、正确率比较,差异均有统计学意义(均P＜0.001)。结论 基层民营口腔诊所医务人员手卫生依从率和正确率均较低,急需相关部门加强对基层民营口腔诊所的手卫生管理。     

应用锥形束CT对种植区牙槽骨质量分类方法的改良研究

目的    应用锥形束CT（cone beam CT，CBCT）测量种植区牙槽骨质量并结合Lekholm和Zarb分类法对骨质量分类方法进行改良，以期为提高牙槽骨质量分类的准确性提供指导。方法    选择2015年10月至2017年10月在呼和浩特市口腔医院种植科进行种植修复的196例患者术前CBCT影像资料，应用 Invivo5诊断设计软件测量306个种植位点的牙槽骨皮质骨厚度和松质骨密度（皮质骨与松质骨的CT值差值），以Lekholm和Zarb分类法为基础结合测量数据对骨质量进行改良后的量化分类。结果    牙槽骨皮质骨厚度为0.18 ~ 2.89 mm，中位数为0.92 mm。皮质骨与松质骨的CT值差值为88.5 ~ 667.8 HU，应用百分位数法找到33.3%和66.6%对应的数值分别为297.8 HU和356.1 HU。依据此数据结合Lekholm和Zarb分类法将196例患者的306个种植位点骨质量分为4类，其中Ⅰ类骨种植位点46个（占15.0%），Ⅱ类骨104个（占34.0%），Ⅲ类骨114个（占37.3%），Ⅳ类骨42个（占13.7%）。结论    结合Lekholm和Zarb分类法，应用CBCT测量种植区牙槽骨质量并进行分类方法的改良，可为临床医生术前评估牙槽骨质量提供一定参考。     

增龄因素对人牙髓干细胞生物学行为影响的研究

目的 对不同年龄患者的牙髓干细胞(human dental pulp stem cells,hDPSCs)进行分离培养,并比较其生物学特性。方法 应用组织块联合胰酶消化法培养不同年龄患者的hDPSCs,记录细胞爬出时间,显微镜下观察比较细胞形态。流式细胞术检测细胞表面抗原,并对细胞行体外成骨、成脂诱导,观察矿化结节和脂滴的形成。CCK8细胞增殖实验比较细胞增殖能力,并通过qRT-PCR比较各组细胞成牙/成骨相关基因牙本质涎磷蛋白(DSPP)、骨钙素(OCN)、核心结合因子α1(RUNX2)、骨桥蛋白(OPN)、Ⅰ型胶原(COL-1)的表达水平。结果 不同年龄患者的hDPSCs基本呈梭形,但随着年龄增长,不规则形态的细胞数目增多,且细胞爬出时间存在统计学差异(P<0.05)。流式细胞术结果显示:各组细胞CD90、CD73高表达,CD146低表达,CD34不表达。在成骨及成脂诱导下,各组细胞均能够形成矿化结节和脂滴。CCK8检测及qRT-PCR结果显示:随着年龄的增长,hDPSCs增殖能力下降,成牙/成骨基因表达水平明显降低(P<0.05)。结论 来自不同年龄供体的牙髓组织中均可提取出具有多向分化能力的干细胞。细胞增殖与年龄相关,各年龄段细胞在一定程度上均可分化为成牙本质细胞/成骨细胞,但随着供体年龄增长,成牙/成骨能力明显降低。     

Application of 3D imaging and selfies in forensic dental identification

With increased access to smartphones, the selfie has gained immense popularity in the past decade. Selfie images could be a significant source of ante-mortem (AM) image data in cases where dental records are unavailable or considered insufficient. The application of 3D imaging and selfies has not been explored to its full potential in human dental identification. The present study aimed to evaluate the feasibility of using selfies as AM data and comparing with 3D post-mortem (PM) scans as an alternative to multiple 2D PM photographs in forensic dental identification. The study sample consisted of 18 selfies (12 matching and 6 non-matching) and 15 3D dental scans obtained from the study participants. The study sample was assessed by 6 experienced forensic odontologists (Raters) in two phases; Phase I-Visual comparison of 2D selfies to 3D scans and Phase II-2D selfies superimposed upon 3D scans. Each rater looked at 15 cases, and a total of 1620 comparisons were made by 6 raters (72 for the 12 matching cases and 1548 were for non-matching) and the opinions for each of the comparisons were analyzed. The results of the study show that use of the 3D superimposition method increased the certainty of the conclusions reached by the raters for the cases with correct matches. Furthermore, 94.2% of the 1548 non-matching comparisons were correctly excluded, compared with 77% for the 2D visual comparison method. The study demonstrated the applicability of this 3D method as a valuable tool in assisting the forensic odontologist with dental identification using selfies.