口腔细菌代谢产碱及其分子生物学研究进展

口腔细菌代谢产碱对牙菌斑生物膜菌群平衡和酸碱平衡极其重要,口腔中唾液和细菌的代谢产碱水平与龋病的发生呈负相关。口腔中代谢产碱是由多细菌多途径组成的复杂体系,受诸多环境因素的密切调控。本文就生物膜中细菌代谢产碱的主要途径、生物膜中细菌代谢产碱与龋病的关系、口腔细菌代谢产碱的分子生物学研究进展等作一综述。     

菌斑生物膜产碱代谢与龋病

口腔微生态内酸碱代谢是调控口腔微生态平衡的重要因素,影响着微生物群落组成和菌斑生物膜形成。菌斑生物膜的产碱代谢可能阻碍产酸耐酸菌在低pH值环境中获得优势地位,恢复并维持微生态平衡;同时也直接升高微生态内pH值,遏制牙表面脱矿。菌斑生物膜主要的产碱活动包括精氨酸脱亚胺酶系统介导的精氨酸代谢和尿素酶介导的尿素水解反应。精氨酸代谢可抑制生物膜中产酸菌生长,促进产碱共生菌生长,促进龋状态下的口腔微生态恢复平衡。尿素代谢可抑制龋病发生,含产碱底物的口腔卫生护理产品具有良好的龋病防治效果。本文就近年来菌斑生物膜的产碱代谢及其与龋病关系等研究进展作一综述。     

菌斑与龋病

菌斑是导致口腔内发病率最高的两种疾病——龋病及牙周病的直接原因。本文综述了近五年来国外学者就菌斑在导致龋病关系上的几个主要方面的研究成果;如细菌的吸附,获得性膜,菌斑内物质代谢,菌斑中的产酸代谢、酸分析和pH测定等。     

薄荷复方煎液对龋病及牙周病致病菌生理活性的影响

目的:研究薄荷复方煎液对龋病及牙周病致病菌产酸及合成细胞外多糖的影响,明确薄荷复方煎液的抗菌机制. 方法:选取血链球菌和牙龈卟啉单胞菌作为实验菌株,研究薄荷复方煎液对口腔细菌产酸及合成水不溶性胞外多糖能力的影响. 结果:薄荷复方煎液使血链球菌和牙龈卟啉单胞菌的产酸量和合成不溶性葡聚糖含量明显减少.结论:薄荷复方煎液对口腔细菌的酸代谢和糖代谢有一定的抑制作用.     

韦荣球菌与龋病和链球菌间的关系

韦荣球菌为口腔微生态的重要成员之一,在人类口腔中呈高丰度分布.韦荣球菌不能代谢糖产酸,但能代谢乳酸,这一点曾被认为对龋病的发生发展有抑制作用,但体外及动物试验对于韦荣球菌在龋病发生中的作用及其机制并未得出明确结论.近来随着口腔微生物组学研究的发展,人们发现,韦荣球菌在龋活跃者口腔中的分布较无龋者高,韦荣球菌与多种致龋菌分布呈高度相关性,韦荣球菌对变异链球菌等致龋菌有促进作用.龋病是多种微生物共同作用的结果,而韦荣球菌作为龋病相关因素不容忽视.本文就韦荣球菌在口腔中的分布、韦荣球菌与龋病的关系、韦荣球菌与链球菌的相互作用等研究进展作一综述,以剖析韦荣球菌在龋病发生发展中的作用及其机制.     

白色假丝酵母菌与龋病的相关性研究

龋病是人类最常见的感染性疾病之一。从生态学角度看,龋病是由于口腔生态平衡失调,正常菌群成为条件致病菌所致。白色假丝酵母菌是寄生于口腔内的一种酵母样真菌,具有致龋菌的生理特征:能与其他细菌共聚黏附于牙面并具有很强的产酸性和耐酸性。笔者综述这方面的研究,以期为龋病防治提供新的思路。     

龋病与唾液溶菌酶、牙菌斑关系的研究

<正> 龋病是由于牙菌斑内的微生物(致龋细菌)在有蔗糖或其他可发酵糖类存在的条件下,使糖发酵产酸,将牙齿组织破坏造成的。这个理论已被人们广泛接受。同时大量研究又证实了唾液溶菌酶对口腔内某些细菌有溶菌作用。而对龋病与溶菌酶活性的关系研究甚少。本文就龋病、牙菌斑、唾液溶菌酶活性的相互关系作一初步分析。     

光动力学疗法预防龋病的研究进展

龋病是影响口腔及全身健康的常见疾病,其患病率高、危害范围广。牙菌斑和细菌代谢产物是龋病形成和发展的主要因素。光动力学疗法是利用光激活光敏剂产生光化学效应,选择性杀伤病原微生物的一种新方法。研究表明,光动力学疗法对致龋菌具有直接的抑制作用,并且不会产生细菌耐药性,有望成为控制菌斑和防治龋病的新方法。本文拟就光动力学疗法预防龋病的研究现状及应用前景作一综述。     

乳酸杆菌在儿童龋病中作用的研究进展

乳酸杆菌（LB）是一种产酸、耐酸性细菌,能高效代谢糖类产酸,使牙体组织脱矿,LB是龋病的主要致病菌,在龋病的发病中起到至关重要的作用,与龋病的发展密切相关,而儿童龋病又有其特点。本文对国内外儿童（年龄<12岁）龋病的流行病学、龋病的菌群分布、致病LB基因型及其与其他致病菌的相互作用在龋病发病中的作用等方面的研究进展作一综述。     

ldh基因在龋病形成过程中的作用

龋病是危害人类口腔健康最常见的疾病,是口腔致龋菌群、宿主、食物及时间多因素综合作用的疾病。据WHO相关研究显示,随着口腔医学的发展,在世界范围内龋失补指数(DMFT)有所下降,但是仍然影响着60~90的学龄儿童和大部分的成年人的身体和生活质量[1]。利用碳水化合物发酵产生乳酸是致龋菌的重要特征,是龋病发生的直接原因。多数口腔细菌可通过代谢碳水化合物产生有机酸,随着代谢酸性产物     

菌斑微生物群落构成变化与儿童龋病相关研究进展

龋病作为多因素影响的疾病,细菌是龋病发生的始动因素,生态菌斑学说的提出以及现代分子生物学手段的应用,使得学者们能够从微生物角度对菌斑生物膜中细菌的种群分布、菌群多样性、菌斑微生物群落变化与儿童龋病之间的联系进行了更深入的探讨.菌群多样性的降低与龋病发生密切相关,早于龋病发生前的6个月就可以检测到菌群多样性水平的降低,这...     

牙菌斑生物膜的细菌生长抑制因子

牙菌斑生物膜中的细菌是龋病发生的先决条件,而口腔内存在多种细菌生长的抑制因子,它们对细菌的生长或菌斑的形成起一定抑制作用。细菌生长的抑制因子主要来自宿主和细菌本身产生的细菌素以及其他代谢产物,本文就致龋菌生长抑制因子的种类及作用的研究进展作一综述。     

The complex oral microflora of high-risk individuals and groups and its role in the caries process

The involvement of the oral biofilm in the caries process requires re-evaluation. The essential role of mutans streptococci (Streptococcus mutans and Streptococcus sobrinus) in the caries process is not proven. Acid production by dental plaque is not dependent upon the presence of mutans streptococci; caries occurs in the absence of these species and their presence does not necessarily indicate caries activity. Other oral bacteria, non-mutans streptococci, Actinomyces spp. and Bifidobacterium spp., are acidogenic and aciduric. They outnumber mutans streptococci in dental plaque, and there are data which support a role for these bacteria in the initiation and progression of caries. Molecular studies demonstrate the great diversity and complexity of the flora associated with caries. Many taxa identified have not been cultured and the role of these taxa is not known. We have, in mutans streptococci, good markers of disease but not necessarily the aetiological agents of the disease. Considerably more research is required to investigate the transition of tooth surfaces from being intact and sound to the white spot lesion stage. A combination of conventional and molecular approaches are required to elucidate the involvement of an individual taxon and of microbial populations with particular traits in the caries process.     

Dental Caries Risk in Relation to Dietary Habits and Dental Services in Two Industrial Populations

Objectives: Environmental hazards contribute to the poor oral health in many occupations. Among the earliest occupations mentioned are those of the baker and confectionery worker. To determine appropriate ways of promoting oral health in places of work, factors affecting caries susceptibility were studied. Methods : Dental caries status, dietary and dental health behaviors, and salivary microbiologic findings in 338 confectionery and 101 shipyard workers were compared. A caries risk index based on salivary findings was used in log-linear models where the effects of sex, diet, use of dental services, and work environment were studied. Results : Caries experience was found to be high in both populations. Dietary habits were the most important factor affecting caries occurrence and susceptibility. Similar dietary behaviors were found in both groups. Conclusions : The confectionery industry did not seem to be an exceptionally hazardous environment for dental health in general. However, the screening of high-risk workers should be organized. Reimbursement of costs had no major effect on use of dental services or caries risk. Oral health promotion should be integrated with existing occupational health services to improve oral health in industrial populations.     

Overview and quality assurance for the oral health component of the National Health and Nutrition Examination Survey (NHANES), 2005-08

The oral health component for the National Health and Nutrition Examination Survey (NHANES) was changed in 2005 from an examination conducted by dentists to an oral health screening conducted by health technologists rather than dental professionals. The oral health screening included a person-based assessment for dental caries, restorations, and sealants. This report provides oral health content information and presents results of data quality analyses that include dental examiner reliability statistics for data collected during NHANES 2005-08. Oral health data are available on 15,342 persons aged 5 years and older representing the civilian, noninstitutionalized population of the United States who participated in NHANES 2005-08. Overall, interrater reliability findings indicate that health technologist performance was excellent with concordance between examination teams and the survey reference examiner being almost perfect for a number of assessments. Concordance for dental caries and sealants (kappa statistics) between health technologists and the survey reference examiner ranged from 0.82 to 0.90 for the combined 4-year period. These findings support the use of health technologists in the assessment of person-based estimators of dental caries and sealant prevalence as part of an oral health surveillance system.     

Increment of dental caries among Finnish dental students during a period of 2 years

The purpose of the study was to estimate the increment of dental caries among dental students in Helsinki, who acquired good knowledge of caries prevention during their studies. The group (59 students) was examined twice with an interval of 20.2 +/- 4.1 months. Clinical findings, augmented with bitewing radiographs and an orthopantomogram, were recorded separately for each tooth surface, and individual DMFS and DS index scores were computed. In addition, the students were interviewed with regard to oral hygiene, topical fluoride application, and dietary habits. The mean DMFS and DS index scores at the first examination were 45.0 and 9.1, respectively. At the second examination, DMFS was 46.4 and the number of new decayed surfaces per student 0.54/year. Both the latter values indicated that caries progression was slow. The increment of dental caries among the dental students was much smaller than that observed earlier among other groups of university students in Finland. Further evidence that caries progression among the dental students was slow was provided by the finding that of the 318 incipient caries lesions recorded at the first examination, no more than 11 had developed into clinical caries by 20 months.     

The relationship between dental caries status and dental plaque urease activity

INTRODUCTION: Ammonia production from the metabolism of urea by urease enzymes of oral bacteria moderates plaque acidification and may inhibit dental caries, as suggested by in vitro studies and indirect clinical observations. The objective of this study was to examine the relationship of urease activity with dental caries at the clinical level. METHODS: Urease activity was measured in dental plaque and saliva samples from 25 caries-free subjects (CF) and in eight subjects with six or more open caries lesions (CA). Plaque and saliva collection was repeated for each subject 1 week later using identical procedures. RESULTS: Urease-specific activity in the dental plaque of CF subjects was significantly higher compared to that in the subjects with caries. The association of low plaque urease levels with increased caries was further supported by odds ratio analysis using different plaque urease cut-off points. Using a receiver operating characteristic curve it was estimated that there was an approximately 85% probability of correctly classifying the subjects as CA or CF based on the relative ordering of their plaque urease activity levels. No statistically significant differences were observed in salivary urease activity. CONCLUSION: This study suggests that loss of alkali-generating potential of tooth biofilms via the urease pathway has a positive relationship to dental caries.     

Correlations of oral bacterial arginine and urea catabolism with caries experience

Background/aim: Alkali generation by oral bacteria plays a key role in plaque pH homeostasis and may be a major impediment to the development of dental caries. To determine if the capacity of oral samples to produce ammonia from arginine or urea was related to caries experience, the arginine deiminase system (ADS) and urease activity in saliva and dental plaque samples were measured in 45 adult subjects. Methods: The subjects were divided into three groups according to caries status; 13 caries‐free (CF) individuals (decayed, missing, and filled teeth = 0); 21 caries‐active (CA) individuals (decayed teeth ≥ 4); and 11 caries‐experienced (CE) individuals (decayed teeth = 0; missing and filled teeth > 0). Real‐time polymerase chain reaction was used to quantify the proportion of certain acid‐ or alkali‐producing organisms in the samples. Results: The amount of ammonia generated from the test substrates by plaque samples was generally higher than that produced by salivary samples in all groups. Significantly higher levels of salivary ADS activity and plaque urease activity were observed in CF subjects compared to CA subjects (P = 0.0004 and P = 0.014, respectively). The proportions of Streptococcus mutans from saliva and dental plaque of CA subjects were significantly higher than those from the CF group (P = 0.0153 and P = 0.0009, respectively). In the CA group, there was an inverse relationship between urease activity and the levels of S. mutans (P < 0.0001). Conclusion: This study supports the theory that increased caries risk is associated with reduced alkali‐generating capacity of the bacteria colonizing the oral cavity; providing compelling evidence to further our understanding of oral alkali‐generation in health and disease.     

Dental health situation in privileged children in Addis Ababa, Ethiopia

Two hundred children 6-7 and 13-14 years of age from private schools in Addis Ababa were examined for oral deposits, periodontal condition, dental fluorosis, and dental caries. The findings indicated a higher level of both periodontal disease and dental carries in the privileged children than in previously surveyed nonprivileged children in Ethiopia. This difference was attributed to a higher sucrose intake in the privileged group. The findings may illustrate a dental health situation that will inevitably develop in Ethiopia with a continuous increase in the sucrose consumption.