新型光纤光学相干层析系统在龋齿诊断中的应用

早期龋齿导致牙齿内部脱矿,使得该区域折射率发生变化,从而导致其后向散射系数增加。利用一种新型的光学相干层析（OCT）系统可以进行口腔龋齿疾病的诊断。该全光纤系统快速准确地获得了人体正常离体牙和具有龋变的离体牙的OCT图像。对比它们的后向散射系数,首次发现具有龋变的离体牙齿的后向散射系数是正常离体牙齿组织的数倍。采用此方法可以对龋齿及早期龋齿进行诊断,对于龋齿早期诊断研究具有重要的意义。     

Saliva microbiomes distinguish caries-active from healthy human populations

The etiology of dental caries remains elusive because of our limited understanding of the complex oral microbiomes. The current methodologies have been limited by insufficient depth and breadth of microbial sampling, paucity of data for diseased hosts particularly at the population level, inconsistency of sampled sites and the inability to distinguish the underlying microbial factors. By cross-validating 16S rRNA gene amplicon-based and whole-genome-based deep-sequencing technologies, we report the most in-depth, comprehensive and collaborated view to date of the adult saliva microbiomes in pilot populations of 19 caries-active and 26 healthy human hosts. We found that: first, saliva microbiomes in human population were featured by a vast phylogenetic diversity yet a minimal organismal core; second, caries microbiomes were significantly more variable in community structure whereas the healthy ones were relatively conserved; third, abundance changes of certain taxa such as overabundance of Prevotella Genus distinguished caries microbiota from healthy ones, and furthermore, caries-active and normal individuals carried different arrays of Prevotella species; and finally, no ‘caries-specific'' operational taxonomic units (OTUs) were detected, yet 147 OTUs were ‘caries associated'', that is, differentially distributed yet present in both healthy and caries-active populations. These findings underscored the necessity of species- and strain-level resolution for caries prognosis, and were consistent with the ecological hypothesis where the shifts in community structure, instead of the presence or absence of particular groups of microbes, underlie the cariogenesis.     

基因工程变链菌防龋疫苗的研制

本文采用我们自己构建的基因工程龋齿疫苗菌株,大罐发酵培养３批、菌体收量平均湿重为２．６７ｇ／Ｌ,表达率为４４．２７％。菌体经超声裂解,硫酸铵和链霉素粗提,再经吸附层检,凝胶过滤和离子交换柱层析等步骤纯化精提ＧＴＦ抗原３批。提纯的ＧＴＦ抗原,平均比活,提纯倍数和收率,分别为５８．３４ｕ／ｍｇ、６．０８倍和１９．２５％。此抗原经ＳＤＳ－ＰＡＧＥ电泳,分子量为５５ＫＤ,纯度达到９６．７％,并对湿度具有较好的稳定性能。且此抗原制备的疫苗免疫家兔具有较好的免疫原性     

Study on the relationship between Helicobacter pylori in the dental plaque and the occurrence of dental caries or oral hygiene index

Background: The aims of our study were to determine the presence of Helicobacter pylori DNA in the dental plaque of Chinese children aged 3–6 years by nested polymerase chain reaction (PCR) and to investigate the relationship between this infection and the occurrence of dental caries or oral hygiene index.
Methods: Two hundred and fourteen children from a kindergarten in Guangzhou City of China were evaluated. The children's plaques were assessed by plaque indices of Quigley–Hein. Dental plaque was analyzed using nested PCR for two sets of primers directed to the 860-bp fragment of H. pylori genomic DNA, which have been reported to be highly sensitive and specific by other researchers.
Results: H. pylori was detected in dental plaque samples from 126 children, and 70 children with dental caries carried H. pylori in dental plaque. Of these children without infection, only 36 of 88 suffered dental caries. Besides, the average dental plaque index of 126 H. pylori -positive children was higher than that of 88 children without infection. In the present study, there was a significant correlation between H. pylori infection and dental caries or dental hygiene.
Conclusion: The oral cavity may be a reservoir for H. pylori infection in children. H. pylori in dental plaque may play a role in the occurrence of dental caries, and poor oral hygiene may represent a risk factor for H. pylori in the oral cavity.     

The role of lead and cadmium in deciduous teeth and saliva on dental caries in children residing in Tehran,Iran

BackgroundLead (Pb) and Cadmium (Cd) are important environmental contaminants. There is no biological monitoring of exposure to these heavy metals and their potential effect on dental caries in children in Tehran, Iran, a polluted megacity. Therefore, the present study investigated the potential association between Pb and Cd levels in primary teeth and saliva and dental caries.MethodsIn a cross-sectional design, 211 children aged 6–11 years referred to Tehran University of Medical Sciences, School of Dentistry and residing in Tehran were examined. Pb and Cd levels of exfoliated primary teeth and stimulated saliva were determined by atomic absorption spectrophotometry (AAS). Dental caries prevalence was evaluated according to WHO criteria. Socioeconomic status, oral hygiene behavior, snacking frequency and salivary pH data were acquired as confounding factors. Frequency and percentages were reported for categorical variables, mean and standard deviation (SD) for continuous variables, and geometric mean for skewed continuous variables. A simple linear regression and Pearson correlation tests were used for statistical analyses. P-values < 0.05 were considered as significant.ResultThe mean (95 % confidence interval) Pb and Cd levels in teeth were 213.26 ppb (164.29–274.84) and 23.75 ppb (20.86–27.05), respectively. The mean Pb and Cd levels in saliva were 11.83 ppb (10.71–13.06) and 3.18 ppb (2.69–3.75), respectively. Furthermore, Pb and Cd in primary teeth and saliva were not associated (p > 0.05) with socioeconomic status, oral hygiene behavior and snacking frequencyConclusionThis study showed no association between Pb and Cd concentrations in primary teeth and in saliva with dental caries prevalence.     

性病梅毒的古病理学研究回顾

在抗生素诞生以前的历史时期,密螺旋体属疾病蔓延于新旧大陆,是继免疫缺陷综合症之前人类无法治愈的性传染疾病。密螺旋体类疾病可分为：性病梅毒、地方性梅毒、雅司病、品他病4种。除品他外的3种疾病均会使骨骼发生特异性感染,最终造成骨骼形态上的特殊改变,其中以梅毒所造成的影响最为显著。考虑到目前国内尚未有学者对性病梅毒所引起的骨变异进行研究,本文通过梳理国外关于梅毒的古病理学研究成果,对性病梅毒的鉴定标准及起源等问题进行阐述。     

Xerostomic medications and oral health: the Veterans Dental Study (part I)

Objectives: To quantify the adverse effects of the number of xerostomic medications on dental caries, oral mucosa, andperiodontal disease. Design: Secondary analysis of across‐sectional study of the Veterans Dental Study. Setting: Four New England area VA outpatient clinics. Subjects: The sample consists of 345 male veterans participating in The Veteran's Dental Study who also had pharmacy records. Main outcome measures: Oral health data included total surfaces of coronal caries, a modification of the root caries index, mean oral mucosa scores, and Community Periodontal Index of Treatment Need (CPITN). Oral health parameters were measured and recorded in clinical dental examinations. Exposures: Intake of xerostomic medications 14‐385 days prior to the dental examination. Statistical Analyses: The relationships between exposure and outcome were analyzed via linear and logistic regression methods adjusting for possible confounding factors such as disease burden index, alcohol consumption, dental care, and smoking status. Results: Veterans who were taking at least one xerostomic medication were almost three times more likely to have mean mucosa scores in the worst 25 percentile than veterans taking no xerostomic medications, OR= 2.63 (confidence interval [CI] 1.34,5.16, p=0.03) after adjusting for age, number of teeth, disease burden index, income, smoking and alcohol use. Participants who were taking at least one xerostomic medication experienced higher but non‐significant increases in coronal (OR =1.21; CI. 0.66, 2.25) and root caries (OR =1.10 CI. 0.54, 2.24) measured by numbers of total decayed surfaces. Conclusion: There were significant deleterious effects of xerostomic medications on oral mucosa. However, xerostomic medications do not appear to increase coronal caries, or periodontal index measured by CPITN among ambulatory, community dwelling participants who were able to perform routine preventive oral care.