Investigation of Salivary Function and Oral Microbiota of Radiation Caries-Free People with Nasopharyngeal Carcinoma

Radiation caries have been reported to be correlated with radiotherapy-induced destruction of salivary function and changes in oral microbiota. There have been no published reports detailing patients who have remained radiation caries-free following radiotherapy for nasopharyngeal carcinoma. The aim of this study was to investigate the relationship between salivary function, oral microbiota and the absence of radiation caries. Twelve radiation caries-free patients and nine patients exhibiting radiation caries following irradiated nasopharyngeal carcinoma were selected. V40, the dose at which the volume of the contralateral parotid gland receives more than 40 Gy, was recorded. Stimulated saliva flow rate, pH values and buffering capacity were examined to assess salivary function. Stimulated saliva was used for molecular profiling by Denaturing Gradient Gel Electrophoresis. Mutans streptococci and Lactobacilli in saliva were also cultivated. There were no significant differences in V40 between radiation caries-free individuals and those with radiation caries. Compared with normal values, the radiation caries-free group had significantly decreased simulated saliva flow rate, while there were no significant differences in the saliva pH value and buffering capacity. Similar results were observed in the radiation caries group. There was no statistical difference in microbial diversity, composition and log CFU counts in cultivation from the radiation caries-free group and the radiation caries group. Eleven genera were detected in these two groups, among which Streptococcus spp. and Neisseria spp. had the highest distribution. Our results suggest that changes in salivary function and in salivary microbiota do not explain the absence of radiation caries in radiation caries-free individuals.     

Molecular-Genetic Mechanisms of Caries Development

This review analyzes the literature in the rapidly developing direction of genetic aspects of caries. The search by key words “genetic markers of caries” in the PubMed database was performed. Afterwards, an analysis of the literature lists of found publications was completed and additional sources were studied. Search by “caries” on the platform of elibrary.ru was performed. From the published data, the role of markers by spectrum of genes in caries development is obvious; however, the development of caries is influenced not only by genetic factors but also by environmental factors. The established molecular-genetic markers of caries development, including genes connected with immunity, saliva content, and rate of saliva formation and also connected with formation of teeth, dentin, and tooth enamel are considered. Social demographic factors and environmental factors (dietary peculiarities, hygiene of mouth cavity, contamination of environment, content of mouth microbiota) influencing caries development are considered. Information from literature sources will help to characterize the modern understanding of caries development and will also make it possible to perform both individual and population screening aiming to develop novel methods of caries prevention taking into account the detected markers of caries, establish groups of risk, and apply a personalized approach in the treatment of the disease.     

Mn and Cu concentrations in mixed saliva of elementary school children in relation to sex,age, and dental caries

To examine the standard Mn and Cu concentrations in mixed saliva from children and the relationship between these levels and dental caries, resting mixed saliva samples obtained from 527 children of an elementary school in Kitakyushu City were collected at 10:00–11:30 a.m. during December 2004. The Mn and Cu concentrations were determined using simultaneous multi-element atomic absorption spectrometry. The standard Mn and Cu levels were 22.0±15.2 and 3.8±4.1 ng/mL, respectively, in the sound teeth group. Mn levels were significantly higher in boys (25.4±17.4 ng/mL) than girls (19.1±12.3 ng/mL) and also higher in upper (25.5±16.4 ng/mL) than lower (19.0±13.5 ng/mL) grades. The Cu level was unaffected by sex and age in the sound teeth group. The Cu level in children with caries experience (5.7±5.3 ng/mL) was significantly higher than that of the sound teeth group. Moreover, the Cu levels in children with untreated caries were significantly higher than that of the sound teeth group, and increased with the number of untreated teeth. No significant difference was found in the Cu concentrations between the group in which all decayed teeth were treated and the sound teeth group. The Mn levels were similar with or without caries and treatment. These findings indicate that the Mn level in mixed saliva depended on sex and age, and suggest the possibility of Cu dissolving into mixed saliva by demineralization due to dental caries.     

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.     

Effect of LGG yoghurt on Streptococcus mutans and Lactobacillus spp. salivary counts in children

The aim of this study was to establish effect of 14 day consumption of commercially available yoghurt containing Lactobacillus rhamnosus ATCC53103 - LGG (Bioaktiv LGG, Dukat, Croatia) on Streptococcus mutans and Lactobacillus spp. salivary counts in children. Twenty five patients, 6-10 yr old participated in the study. At the inclusion in the study caries risk for every patient was evaluated. The saliva samples were tested with chair side kits for saliva buffer capacity (CRT buffer, Vivadent, Schaan, Liechtenstein), S. Mutans and Lactobacillus counts (CRT bacteria test, Vivadent, Schaan, Liechtenstein). Seven, 14 and 30d after yoghurt consumption saliva samples were tested again with CRT buffer and CRT bacteria tests. Obtained data were analyzed using chi2 and Kruskal-Wallis tests. Results showed significant increase in saliva buffer capacity 30d after yoghurt consumption. S. Mutans salivary counts were significantly decreased after 30d. Significant differences in Lactobacillus counts were not observed. It could be concluded that daily consumption of yoghurt containing LGG have an inhibitory effect on oral pathogenic bacteria and may be beneficial in caries prevention.     

Correlation between the cariogenic response in biofilms generated from saliva of mother/child pairs

This study aimed to correlate the cariogenic responsiveness of biofilms generated from the saliva of mothers and children. The mother–child pairs were classified according to the children’s caries levels: caries-free, early childhood caries (ECC) or severe ECC. Microcosm biofilms were grown on enamel discs for 10?days. Factors under evaluation were caries experience levels, inoculum source (mothers and children) and growth conditions including cariogenic challenge (growth medium provided with and without sucrose) and no cariogenic challenge (growth medium sucrose-free). Statistical analysis was performed with ANOVA and Tukey’s test, and the Spearman correlation test. Regular sucrose exposure resulted in a higher surface hardness change (%SHC). The correlation between biofilms formed from saliva of mother–child pairs was significant regarding pH, total aciduric microorganisms and lactobacilli counts under cariogenic challenge. Biofilm growth originating from mother–child pairs under regular sucrose exposure promoted the same cariogenic response independently of caries experience and the microbiological profile of the donors.     

健康与龋病口腔唾液中乳杆菌的发酵类群与表面性质

目的 研究口腔健康的成年人和龋病患者唾液中乳杆菌的发酵类群和表面性质。方法 糖酸以口腔健康的成年人和龋病患者为对象,取其早餐后2 h的无刺激全唾液分离乳杆菌,检验其对葡萄糖和葡萄糖酸钠发酵的情况;应用MATH（Microbiol Adhesion to Hydrocarbons）法测定菌体表面疏水性和电荷。结果 口腔健康的成年人与龋病患者唾液中乳杆菌各发酵类群的比例不同,前者表面疏水性和电荷比较高,后者比较低。结论 口腔健康的成年人和龋病患者唾液中乳杆菌的组成不同,表面性质也不同,特定种类的乳杆菌与龋病的发展相关。     

The role of the saliva antioxidant barrier to reactive oxygen species with regard to caries development

Objectives: The aim of this study was to evaluate the role of the antioxidant barrier in the saliva of children with caries, and its impact on the colonization of cariogenic bacteria.

Methods: This is a cross-sectional study of 81 children aged 1–5 years. Antioxidant levels and salivary bacterial profiles were measured. Patients were divided into two groups as follows: initial stage decay, termed non-cavitated (1–2 in International Caries Detection and Assessment System (ICDAS)), and extensive decay, termed cavitated lesions (5–6 in ICDAS). The control group includes children without caries.

Results: The linear regression model demonstrated that the GSH, GSSG, GSH/GSSG, and total antioxidant capacity levels are influenced (P?P?Discussion: Our results indicate that the high levels of antioxidants in saliva increase significantly in children in line with the salivary cariogenic bacterial profiles and caries progression.     

Association Between Obesity,Flow Rate of Whole Saliva,and Dental Caries in Adolescents

In a cross‐sectional study design, we test the hypothesis whether childhood obesity is associated with reduced flow rate of stimulated whole saliva and dental caries. Obese adolescents (n = 65) with a mean age of 14.5 years and normal weight subjects (n = 65) with a mean age of 14.2 years were clinically examined with respect to dental caries, visible plaque accumulation (visible plaque index (VPI%)), gingival inflammation in terms of bleeding on probing (BOP%) as well as answered a questionnaire concerning medical history, medication, oral hygiene habits, smoking habits, and sociodemographic background. The flow rate of stimulated whole saliva (ml/min) was determined. BMI was calculated and adjusted for age and gender (BMI‐sds). The obese subjects exhibited higher number of decayed surfaces (DS), 0.7 vs. 0.1 (P = 0.008) and lower flow rate of stimulated whole saliva 1.2 vs. 2.0 ml/min (P < 0.001). Of obese patients, 17 subjects had VPI% >25 and 21 had BOP% >25, both compared to only 5 subjects of the normal weight with P values of 0.005 and <0.001, respectively. In a multivariate logistic regression model BMI‐sds was significantly associated with the flow rate of stimulated whole saliva less than the median value 1.5 ml/min (P < 0.001; odds ratio (OR) 1.36) as well as with DS (DS >0) (P = 0.002; OR 1.31) and the associations were not found to be confounded by any of the studied variables. The results indicate that childhood obesity is associated with reduced flow rate of stimulated whole saliva and dental caries and further strengthens obesity's negative effect on children's oral health.     

The scientific exploration of saliva in the post-proteomic era: from database back to basic function

The proteome of human saliva can be considered as being essentially completed. Diagnostic markers for a number of diseases have been identified among salivary proteins and peptides, taking advantage of saliva as an easy-to-obtain biological fluid. Yet, the majority of disease markers identified so far are serum components and not intrinsic proteins produced by the salivary glands. Furthermore, despite the fact that saliva is essential for protecting the oral integuments and dentition, little progress has been made in finding risk predictors in the salivary proteome for dental caries or periodontal disease. Since salivary proteins, and in particular the attached glycans, play an important role in interactions with the microbial world, the salivary glycoproteome and other post-translational modifications of salivary proteins need to be studied. Risk markers for microbial diseases, including dental caries, are likely to be discovered among the highly glycosylated major protein species in saliva. This review will attempt to raise new ideas and also point to under-researched areas that may hold promise for future applicability in oral diagnostics and prediction of oral disease.     

Salivary metabolite signatures of children with and without dental caries lesions

A metabolomic approach was used to analyze endogenous metabolites and to correlate with a specific biological state. The analysis of salivary metabolites is a growing area of investigation with potential for basic and clinical applications. Analyses of children’s saliva in different dentitions and with or without caries could potentially reveal a specific profile related to oral disease risk. Nuclear Magnetic Resonance (NMR) is well suited for mixture analysis followed by Principal Component Analysis combined with Linear Regression (PCA-LR) statistics and was used to identify differences in the salivary metabolites. The classificatory analysis was performed using PCA-LR based on 1,000 cross-validation bootstrap runs from both classifiers in order to increase the data information from a small sample size. The PCA-LR presented a statistically good classificatory performance for children with and without caries with an accuracy of 90.11 % (P < 0.001), 89.61 % sensitivity (P < 0.001), and 90.82 % specificity (P < 0.001). Children with caries lesions presented higher levels of several metabolites, including lactate, fatty acid, acetate and n-butyrate. Saliva from subjects with different dentition stages was also analyzed. Although the salivary samples were poorly classified, permanent dentition presented increased levels of acetate, saccharides and propionate. The NMR data and PCA-LR were able to classify saliva from children with or without caries, with performance indexes comparable to the partial least-squares regression discriminant analysis (PLS-DA) results also performed. Our data also showed similar salivary metabolite profiles for healthy subjects despite the differences in their oral hygiene habits, socioeconomic status and food intake.     

Enhancing CCL28 expression through the gene transfer to salivary glands for controlling cariogenic microbe

The chemokine CCL28 participates in direct antimicrobial activities as well as homing of certain types of lymphocytes. The present study was conducted to harness these properties of the chemokine for the prevention of dental caries. The gene encoding CCL28 was transferred to salivary glands to enhance the production of this chemokine locally. First, a recombinant eukaryotic plasmid expressing CCL28 was constructed. Then, the CCL28 protein from 293 cells transfected with the recombinant plasmid was verified to inhibit the caries pathogen Streptococcus mutans (S. mutans) in a biofilm. Finally, the recombinant plasmid was retrogradely administered to the parotid glands of rats through the secretory ducts. The successful transfer of the gene encoding CCL28 to rat parotid acinar cells was confirmed by immunofluorescence and real-time PCR. Increases in both CCL28 and secretory IgA (SIgA) in the rat saliva were tested by ELISA. It was revealed that the CCL28 protein obtained from the study was able to strongly inhibit S. mutans living in biofilm in vitro. The delivery of the recombinant plasmid to the rat parotid glands was able to induce high levels of CCL28 and SIgA in saliva, and the increased levels of CCL28 and SIgA in saliva were maintained for 2 weeks. Notably, the dental plaque from the rats treated with the delivery of the recombinant plasmid in the study harbored significantly less S. mutans. These data indicated that the present strategy may hold hope for the effective prevention of dental caries.     

Predictors of caries in old age

This study measured the incidence of dental caries for one year and identified factors associated with the risk of caries in a sample of 156 elderly subjects. The subjects were examined at baseline and after one year to record the number of missing, filled and decayed teeth, to measure oral hygiene and flow of saliva, and to estimate the numbers of Streptococcus mutans and Lactobacilli cultured from samples of saliva. All subjects were interviewed on both occasions for information on their use of medications and dental services and on their ingestion of sugar. At baseline the elders had a mean of 19 natural teeth with 5 decayed surfaces (DS), 38 filled surfaces and a mean Plaque Index (PI) of 1. The independent group, on average, had more teeth and fillings but a lower PI and less caries. At the end of the year more than two-thirds (71%) of the 98 institutionalised subjects and over half (59%) of the 58 independent subjects had at least one new decayed/filled surface (DFS). The mean net DFS increment per subject was 4.6 and 2.0 respectively. Regression analyses on multivariate models identified caries at baseline, residence in long term care facilities, high numbers of Lactobacilli, poor oral hygiene and frequent sugar consumption as the variables contributing most significantly to the risk of caries in old age.     

Effect of mutacin administration on Streptococcus mutans-induced dental caries in rats

A bacteriocin from serotype c Streptococcus mutans strain C3603 was examined for its inhibitory effect on experimental dental caries in rats infected with S. mutans MT8148R (serotype c). Significant reduction in the incidence of dental caries was found only when bacteriocin was incorporated both in the drinking water and in the diet at a high concentration. However, caries reduction was not as great as expected and the addition of bacteriocin to drinking water alone had no effect on the recovery of S. mutans, plaque deposition or caries incidence. The bacteriocin activity must have been reduced in the oral cavity of rats, and the reasons were examined. Bacteriocin-resistant mutants were not detected and the bacteriocin was not inactivated by saliva. Whereas the bacteriocin did not kill the S. mutans cells grown in a sucrose-containing medium, it completely killed the cells grown in a sucrose-free medium.     

Comparison of Oral Microbial Profiles between Children with Severe Early Childhood Caries and Caries-Free Children Using the Human Oral Microbe Identification Microarray

Objective

Early childhood caries (ECC) has become a prevalent public health problem among Chinese preschool children. The bacterial microflora is considered to be an important factor in the formation and progress of dental caries. However, high-throughput and large-scale studies of the primary dentition are lacking. The present study aimed to compare oral microbial profiles between children with severe ECC (SECC) and caries-free children.

Methods

Both saliva and supragingival plaque samples were obtained from children with SECC (n = 20) and caries-free children (n = 20) aged 3 to 4 years. The samples were assayed using the Human Oral Microbe Identification Microarray (HOMIM).

Results

A total of 379 bacterial species were detected in both the saliva and supragingival plaque samples from all children. Thirteen (including Streptococcus) and two (Streptococcus and Actinomyces) bacterial species in supragingival plaque and saliva, respectively, showed significant differences in prevalence between the two groups. Of these, the frequency of Streptococcus mutans detection was significantly higher in both saliva (p = 0.026) and plaque (p = 0.006) samples from the SECC group than in those from the caries-free group.

Conclusions

The findings of our study revealed differences in the oral microbiota between the SECC and caries-free groups Several genera, including Streptococcus, Porphyromonas, and Actinomyces, are strongly associated with SECC and can be potential biomarkers of dental caries in the primary dentition.     

Analysis of Oral Microbiota in Children with Dental Caries by PCR-DGGE and Barcoded Pyrosequencing

Oral microbiota plays a vital role in maintaining the homeostasis of oral cavity. Dental caries are among the most common oral diseases in children and pathogenic bacteria contribute to the development of the disease. However, the overall structure of bacterial communities in the oral cavity from children with dental caries has not been explored deeply heretofore. We used high-throughput barcoded pyrosequencing and PCR-denaturing gradient gel electrophoresis (DGGE) to examine bacterial diversity of oral microbiota in saliva and supragingival plaques from 60 children aged 3 to 6 years old with and without dental caries from China. The multiplex barcoded pyrosequencing was performed in a single run, with multiple samples tagged uniquely by multiplex identifiers. As PCR-DGGE analysis is a conventional molecular ecological approach, this analysis was also performed on the same samples and the results of both approaches were compared. A total of 186,787 high-quality sequences were obtained for evaluating bacterial diversity and 41,905 unique sequences represented all phylotypes. We found that the oral microbiota in children was far more diverse than previous studies reported, and more than 200 genera belonging to ten phyla were found in the oral cavity. The phylotypes in saliva and supragingival plaques were significantly different and could be divided into two distinct clusters (p < 0.05). The bacterial diversity in oral microbiome analyzed by PCR-DGGE and barcoded pyrosequencing was employed to cross validate the data sets. The genera of Streptococcus, Veillonella, Actinomyces, Granulicatella, Leptotrichia, and Thiomonas in plaques were significantly associated with dental caries (p < 0.05). The results showed that there was no one specific pathogen but rather pathogenic populations in plaque that significantly correlated with dental caries. The enormous diversity of oral microbiota allowed for a better understanding of oral microecosystem, and these pathogenic populations in plaque provide new insights into the etiology of dental caries and suggest new targets for interventions of the disease.     

Effects of Fluoridated Milk on Root Dentin Remineralization

Background

The prevalence of root caries is increasing with greater life expectancy and number of retained teeth. Therefore, new preventive strategies should be developed to reduce the prevalence of root caries. The aim of this study was to investigate the effects of fluoridated milk on the remineralization of root dentin and to compare these effects to those of sodium fluoride (NaF) application without milk.

Methods

Thirty extracted human molars were divided into 6 groups, and the root cementum was removed from each tooth. The dentin surface was demineralized and then incubated with one of the following six solutions: Sodium chloride NaCl, artificial saliva, milk, milk+2.5 ppm fluoride, milk+10 ppm fluoride and artificial saliva+10 ppm fluoride. Serial sections were cut through the lesions and investigated with polarized light microscopy and quantitative morphometry, scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). The data were statistically evaluated using a one-way ANOVA for multiple comparisons.

Results

The depth of the lesion decreased with increasing fluoride concentration and was the smallest after incubation with artificial saliva+10 ppm fluoride. SEM analysis revealed a clearly demarcated superficial remineralized zone after incubation with milk+2.5 ppm fluoride, milk+10 ppm fluoride and artificial saliva+10 ppm fluoride. Ca content in this zone increased with increasing fluoride content and was highest after artificial saliva+10 ppm fluoride incubation. In the artificial saliva+10 ppm fluoride group, an additional crystalline layer was present on top of the lesion that contained elevated levels of F and Ca.

Conclusion

Incubation of root dentin with fluoridated milk showed a clear effect on root dentin remineralization, and incubation with NaF dissolved in artificial saliva demonstrated a stronger effect.     

Rehardening of caries-like lesions in root surfaces by saliva substitutes

Objective: This study sought to evaluate whether root dentine caries‐like lesions could be remineralised by saliva substitutes. Methods: Root dentine slabs (3 × 3 × 2 mm) were cut from bovine incisors, ground flat, polished and pre‐tested for Knoop microhardness (KHN) at five locations spaced 500 μm apart and 500 μm from the left edge of each sectioned piece. After 60 out of the 100 slabs had been selected based upon their KHN values, specimens were coated with wax except for their outer surface. Specimens were then cycled through a highly cariogenic challenge model to induce caries‐like lesions, whose formation was confirmed by KHN measurements located 500 μm from the right edge of the specimen. According to a randomised complete block design, the experimental units (n = 15) were exposed to 1.5 ml of saliva substitutes, based on either mucin (MC) or carboxymethylcellulose (CM), to natural human saliva (HS) or to 100% relative humidity (RH) over 20 days. Remineralisation was verified by KHN measurements located 1000 μm apart from the right edge of the specimen. Results: Analysis of variance indicated a significant (p < 0.0001) difference among the KHN values attained by the carious root dentine after exposure to the remineralising agents. Tukey's test ascertained that remineralisation was greatest with MC, intermediate with CM and least with HS, but rehardening did not reach the pre‐caries lesion formation values. Conclusion: Saliva substitutes may provide partial remineralisation to preformed caries‐like lesions in root dentine.     

Elevated incidence of dental caries in a mouse model of cystic fibrosis

Background

Dental caries is the single most prevalent and costly infectious disease worldwide, affecting more than 90% of the population in the U.S. The development of dental cavities requires the colonization of the tooth surface by acid-producing bacteria, such as Streptococcus mutans. Saliva bicarbonate constitutes the main buffering system which neutralizes the pH fall generated by the plaque bacteria during sugar metabolism. We found that the saliva pH is severely decreased in a mouse model of cystic fibrosis disease (CF). Given the close relationship between pH and caries development, we hypothesized that caries incidence might be elevated in the mouse CF model.

Methodology/Principal Findings

We induced carious lesions in CF and wildtype mice by infecting their oral cavity with S. mutans, a well-studied cariogenic bacterium. After infection, the mice were fed a high-sucrose diet for 5 weeks (diet 2000). The mice were then euthanized and their jaws removed for caries scoring and bacterial counting. A dramatic increase in caries and severity of lesions scores were apparent in CF mice compared to their wildtype littermates. The elevated incidence of carious lesions correlated with a striking increase in the S. mutans viable population in dental plaque (20-fold increase in CF vs. wildtype mice; p value<0.003; t test). We also found that the pilocarpine-stimulated saliva bicarbonate concentration was significantly reduced in CF mice (16±2 mM vs. 31±2 mM, CF and wildtype mice, respectively; p value<0.01; t test).

Conclusions/Significance

Considering that bicarbonate is the most important pH buffering system in saliva, and the adherence and survival of aciduric bacteria such as S. mutans are enhanced at low pH values, we speculate that the decrease in the bicarbonate content and pH buffering of the saliva is at least partially responsible for the increased severity of lesions observed in the CF mouse.     

新疆博州地区三民族儿童口腔优势菌群结构

目的研究新疆博州地区汉族、维吾尔族和蒙古族3～5岁儿童的口腔唾液细菌优势菌群结构多样性的差异,并探讨与低龄儿童龋发生的相关性。方法从本课题组在新疆博州地区3～5岁儿童口腔流行病学调查时建立的资料样本库中选取唾液样本120例(汉族40例,维吾尔族40例,蒙古族40例)作为研究对象,其中每个民族中高龋组(ECC)各20例,无龋组(CF)各20例,取非刺激性唾液,提取细菌DNA后进行聚合酶链反应(PCR)扩增和变性梯度凝胶电泳(DGGE)分析,采用Quantity One软件对PCR-DGGE指纹图谱进行数据分析。结果 DGGE总体图谱表明:口腔微生物菌群结构具有民族差异性和个体差异性;维吾尔族总的条带数和多样性指数(条带数:87.00±10.40,多样性指数:5.99±1.12)大于汉族(条带数:63.00±8.07,多样性指数:3.29±0.74)和蒙古族(条带数:71.60±5.79,多样性指数:4.98±0.50)(P0.05),高龋儿童组的细菌菌群结构多样性小于无龋儿童组(P0.05),无龋儿童组的细菌菌群结构多样性存在民族差异(P0.05);聚类分析发现:每个民族组内大部分样本均表现出明显的聚类群。结论博州地区儿童口腔唾液细优势菌群结构多样性在民族之间差异明显,在低龄儿童龋病进展中,细菌多样性逐渐减少。