Influence of colonization with mutans streptococci on caries risk in Japanese preschool children: 24 month survival analysis

PURPOSE: This study evaluates how various microbial- and salivary-related risk factors influenced the hazard for caries development in preschool children. METHODS: The study population consisted of 131 subjects (age: 0.5 to 6.0 yrs). Oral examination, including two bacterial tests and buffering capacity test, was conducted at six month intervals over 24 months. A survival analysis was used to describe caries hazard over a 24-month follow-up period. A Cox proportional hazards regression analysis was performed to test the influence of salivary mutans streptococci (MS), aciduric bacteria, buffering capacity and age on caries development. RESULTS: Of the total subjects, 60 children (46%) were found to be caries-free at baseline. Caries hazard correlated significantly with salivary MS levels at baseline (relative risk, 1.7; P = 0.003), but not with aciduric bacteria and buffering capacity. This analysis showed that all of children with high colonization of MS at baseline had dental caries 15 months later. CONCLUSION: The results suggest that salivary MS level at baseline influenced caries hazard in preschool children.     

Relationship among salivary carbonic anhydrase VI activity and flow rate, biofilm pH and caries in primary dentition

This study aimed to determine the activity of carbonic anhydrase isoenzyme VI (CAVI) in the saliva of preschool children with caries and to investigate the relationship between caries and salivary CAVI activity, salivary flow rate and biofilm pH before and after a 20% sucrose rinse. Thirty preschool children aged 45.3-80.3 months were divided into two groups: a caries-free group and a caries group. Clinical examinations were conducted by one examiner (κ = 0.95) according to WHO criteria (dmfs) and early caries lesions. From each subject, CAVI activity, salivary flow rate and plaque pH were determined before and after a sucrose rinse. The results were submitted to Wilcoxon, Mann-Whitney and Spearman correlation tests (α = 0.05). The results showed that prerinse CAVI activity and its variation were higher in the saliva from caries children than from caries-free children. No difference was found between the two groups in postrinse salivary CAVI activity. After rinsing, biofilm pH differences were lower in both groups (p = 0.0012 and p = 0.0037 for the caries and caries-free groups, respectively). Also, after the sucrose rinse, salivary flow rate significantly increased in caries and caries-free groups (p = 0.0003, p = 0.0037). The variation of salivary CAVI activity was negatively correlated with caries (r = -0.501, p = 0.005). Child's age showed a positive correlation with caries (r = 0.456, p = 0.011). These results suggest that variation of salivary CAVI activity and child's age are associated with dental caries in preschool children.     

Streptococcus mutans infection level and caries in a group of 5-year-old children

The level of Streptococcus mutans in stimulated saliva and its association with caries experience was evaluated in 149 5-year-old children. In general, salivary S. mutans levels were low, and it was detected only in 46% of saliva samples. There was, however, a clear association between salivary levels of S. mutans and caries experience (chi 2 = 53.65, p less than 0.001). Salivary examination was supplemented with plaque samples in 47 children. The number of S. mutans positive surfaces increased with increasing salivary levels. S. mutans was most often isolated and comprised the highest proportion in the approximal samples. The number of children with high salivary S. mutans levels was very low (6%) when taken into account that 13% of the children were fairly caries active (dmfs greater than or equal to 5). This most probably means that in evaluation of caries risk, the salivary S. mutans screening level is different in preschool children and in older children. The level should be determined in longitudinal studies before applying to preschool children.     

沈阳市幼儿园5岁儿童乳牙龋病流行病学抽样调查报告

目的 调查沈阳市幼儿园5岁儿童乳牙龋患病情况.方法 采用分层等容量随机抽样的方法,抽取沈阳市内5区5岁常住人口440人及其家长,男女各半.检查儿童全口乳牙牙冠龋病情况,统计患龋率、龋均等,将所得数据与本地区1995年的调查数据进行比较;并对家长进行儿童饮食习惯、刷牙情况等的问卷调查.结果 乳牙患龋率为67.05％,龋均为3.10,龋齿充填完好率5.51％,曾接受过龋齿治疗的占8.41％.与1995年沈阳市幼儿园5岁儿童乳牙龋病情况比较,患龋率有所下降(P＜0.001),龋均亦有下降(P＜0.001).问卷调查中有睡前进甜食行为者占41.28％,定期进行口腔健康检查者只占2.04％,在家长监督下有效刷牙率为10.17％,家长对儿童口腔健康状况满意率为82.91％.结论 沈阳市幼儿园5岁儿童乳牙患龋率与1995年相比虽然有所下降,但仍占较高比例.家长对儿童口腔健康认识程度低与高患龋率有关,对家长的口腔健康教育有待加强.     

Salivary mutans streptococci and dental caries in three-year-old children after maternal exposure to chewing gums containing combinations of xylitol, sorbitol, chlorhexidine, and fluoride

The aim of this study was to evaluate the effect of maternal use of chewing gums containing combinations of xylitol, sorbitol, chlorhexidine, and fluoride on salivary mutans streptococci (MS) counts and caries prevalence in the mothers' 3-year-old children. After screening 416 women with newborn babies, 173 mothers with high counts of salivary MS were randomly assigned into 3 experimental chewing gum groups containing (A) xylitol (n = 61), (B) chlorhexidine/xylitol/sorbitol (n = 55), and (C) sodium fluoride/xylitol/ sorbitol (n = 57). Mothers with low or medium MS counts formed a reference group (D) without any intervention (n = 232). The participants in the experimental groups were instructed to chew one piece of the gum for 5 min 3 times a day. The chewing regimen started when the child was 6 months old and was terminated 1 year later. The outcome measures were salivary MS counts and caries prevalence at the age of 3 years. Bacterial enumeration was carried out with a chair-side technique and caries (defs) was scored by clinical examination. Medium and high counts of salivary MS were found in 13%, 16%, and 22% in groups A, B, and C, respectively. The mean defs was 0.1 in group A, 0.2 in group B, and 0.4 in group C. The differences concerning salivary MS and caries were not statistically significant. The MS counts and caries prevalence in children of mothers with low MS counts (group D) were similar to those found in groups A and B. In conclusion, lower but non-significant levels of salivary MS and dental decay were observed in 3-year-old children to mothers who used high-content xylitol gums compared with those who used lower amounts of xylitol. The efficiency of this type of targeted intervention in a low-caries community may be questioned.     

Salivary mutans streptococci and dental caries in three-year-old children after maternal exposure to chewing gums containing combinations of xylitol,sorbitol, chlorhexidine,and fluoride

The aim of this study was to evaluate the effect of maternal use of chewing gums containing combinations of xylitol, sorbitol, chlorhexidine, and fluoride on salivary mutans streptococci (MS) counts and caries prevalence in the mothers' 3-year-old children. After screening 416 women with newborn babies, 173 mothers with high counts of salivary MS were randomly assigned into 3 experimental chewing gum groups containing (A) xylitol (n=61), (B) chlorhexidine/xylitol/sorbitol (n=55), and (C) sodium fluoride/xylitol/sorbitol (n=57). Mothers with low or medium MS counts formed a reference group (D) without any intervention (n=232). The participants in the experimental groups were instructed to chew one piece of the gum for 5 min 3 times a day. The chewing regimen started when the child was 6 months old and was terminated 1 year later. The outcome measures were salivary MS counts and caries prevalence at the age of 3 years. Bacterial enumeration was carried out with a chair-side technique and caries (defs) was scored by clinical examination. Medium and high counts of salivary MS were found in 13%, 16%, and 22% in groups A, B, and C, respectively. The mean defs was 0.1 in group A, 0.2 in group B, and 0.4 in group C. The differences concerning salivary MS and caries were not statistically significant. The MS counts and caries prevalence in children of mothers with low MS counts (group D) were similar to those found in groups A and B. In conclusion, lower but non-significant levels of salivary MS and dental decay were observed in 3-year-old children to mothers who used high-content xylitol gums compared with those who used lower amounts of xylitol. The efficiency of this type of targeted intervention in a low-caries community may be questioned.     

Temporal Changes in Dental Caries Levels and Patterns in a Native American Preschool Population

Objectives : The purposes of this study were to assess current dental caries experience and levels of mutans streptococci in Apache children in 1993 and to determine how caries levels and patterns were different from 15 years before. Methods : Four-year-old Head Start children ( n =127) were examined for dental caries and sampled for salivary mutans streptococci in 1993. Dental caries information on 113 4-year-old children from the same location was obtained from a chart audit of the 1978–79 Head Start dental examinations. Results : Neither the caries prevalence (95%) nor the prevalence of caries patterns differed between the 1978–79 and 1993 cohorts. However, the level of treatment received in 1993 was greater than that in 1978–79. Children with nursing caries (64%) had a greater severity of fissure caries and a greater prevalence of posterior proximal caries compared with caries-positive children without nursing caries. The mean dmfs and dmft of the children categorized in the high mutans streptococci range were greater than those of children categorized in the moderate range. Conclusion : The caries prevalence found in these preschool Native Americans is among the highest reported for this age group and does not differ from that found at this location 15 years before. It appears that children with nursing caries in this population are at greater risk for posterior caries patterns.     

Salivary caries-related tests as predictors of future caries increment in teenagers. A three-year longitudinal study

The aim of the study was to evaluate the capability of caries-related salivary tests and a test based on past caries experience (baseline DFS) to select persons at high risk for caries. The subjects (n = 122) were 12-17 years old at the beginning of the study. Caries was registered and salivary samples were taken annually during the 3-study period. The 3-year caries increment was positively correlated to the baseline DFS (r = 0.46, p less than 0.001), salivary level of mutans streptococci (r = 0.30, p less than 0.001) and lactobacilli (r = 0.30, p less than 0.001), and combined level of mutans streptococci and lactobacilli (r = 0.39, p less than 0.001) and negatively correlated to the buffering capacity of saliva (r = -0.22, p less than 0.05). Tests based on either past caries experience or mutans streptococci or lactobacilli levels alone were not efficient in selecting persons at high risk for caries. Among the tests, DFS was the most sensitive and specific. A combination of either microbial test and DFS was more efficient to select persons at risk than various alternatives alone. The sensitivity was 84% and the specificity 62% for the combination of lactobacilli test and DFS and 71% and 79% respectively for the combination of mutans streptococci and DFS. In the former combination the positive prediction value was 43% and in the latter 56%.     

Caries prevalence and salivary mutans streptococci in 0–2-year-old children of Japan

The prevalence of caries and the number and species distribution of salivary mutans streptococci in 356 children (aged 0-2 yr old) in Japan were examined twice at an interval of 1 yr. No mutans streptococci were isolated from the predentate children. The detection rate of mutans streptococci and the prevalence of caries increased with age. Mutans streptococci were isolated from 39.9% of the subjects. The majority of isolates were identified as Streptococcus mutans. The concentration of mutans streptococci correlated with the number of erupted teeth (r = 0.339). In addition, the concentration of mutans streptococci was more closely correlated to the caries prevalence of the next year (r = 0.465) than that of the year when the salivary concentration of mutans streptococci was first evaluated (r = 0.368). The children who had no caries but harbored mutans streptococci in the first year showed significantly higher caries prevalence in the next year than did the children with neither caries nor mutans streptococci. These results indicate that the establishment of mutans streptococci is associated with caries initiation in early childhood.     

四川省南充市学龄前儿童龋病干预效果评价

目的:了解南充市参与“学龄前儿童口腔疾病综合干预项目”的3岁儿童3年内的患龋状况,监测龋病的发展趋势,评估“学龄前儿童口腔疾病综合干预项目”的效果,为南充市儿童口腔卫生保健规划提供信息和科学依据。方法:将2567名南充市参与“学龄前儿童口腔疾病综合干预项目”的儿童作为调查对象,根据WHO口腔健康调查基本方法对其的患龋状况在干预前后连续调查3年(2012年~2014年),并与南充市1583名未参与项目的3岁儿童作对比。采用SPSS23.0 软件进行统计学分析。结果:南充市参与项目的3岁儿童2012~2014年的患龋率分别为68.5%,70.4%,73.7%,未参与项目的儿童分别为69.7%,76.7%,85.1%,两组患龋率均随年龄呈上升趋势(P<0.05),参与项目的儿童的龋病发生率低于同龄未参与项目的儿童(P<0.05)。结论:南充市3岁儿童乳牙的患龋率较高,“学龄前儿童口腔疾病综合干预项目”对幼儿的防龋效果明显,值得推广应用。     

Distribution and prevalence of dental caries in Bauru, Brazil, 1976-2006

AIMS: To compare caries prevalence and severity, as well as the disease distribution in the permanent dentition of 12-year-old schoolchildren in Bauru, Brazil, from 1976 to 2006. METHODS: Probabilistic samples were obtained in six surveys, from 1976 to 2006, which were conducted by calibrated examiners, following the same protocol. For data analysis, the DMFT (decayed, missing and filled teeth), Significant Caries Index (SiC Index), percentage of caries-free children, Gini Coefficient and Care Index were determined. RESULTS: The means (SD) for DMFT were 9.89 (3.96), 6.98 (3.80), 4.30 (3.11), 4.29(3.44), 1.53(2.07), and 0.90(1.53) in 1976, 1984, 1990, 1995, 2001 and 2006, respectively. Except for years 1990 and 1995 and also for 2001 and 2006, there were statistically significant differences in mean DMFT among the surveys (p < 0.05). The number of caries-free children (DMFT=0), which has significantly increased over the years (p < 0.001), ranged from 0.4% in 1976 to 63.8% in 2006. The SiC Indexes were 14.34, 11.42, 7.74, 8.06, 3.89, and 2.63; the Care Index were 31.9%, 57.4%, 68.7%, 50.5%, 66.4%, and 56.3%; and the Gini Coefficients were 0.23, 0.30, 0.39, 0.43, 0.66, and 0.76 in the surveys. CONCLUSION: Dental caries experience and prevalence in 12-year-old schoolchildren have declined significantly during the last 30 years in Bauru.     

An ecological study on the association of public dental health activities and sociodemographic characteristics with caries prevalence in Japanese 3-year-old children

The aim of this ecological study was to determine the association of the frequency of dental health activities conducted as public health service and sociodemographic characteristics with caries prevalence in Japanese 3-year-old children using data for each municipality as one unit. Data on caries prevalence in 3-year-old children in 2000 were obtained from 3,251 municipalities (almost all municipalities in Japan). Caries prevalence for each municipality was recalculated using the empirical Bayes estimation model to make adjustments for variations in municipalities with small numbers of children. Explanatory factors included annual frequency of dental health activities such as dental health education and topical fluoride application programs and various sociodemographic characteristics. Multiple linear regression analysis was applied to examine the associations between caries prevalence and annual frequency of dental health activities with adjustment of other sociodemographic variables. Variations in caries prevalence in municipalities with small populations became smaller after being adjusted by the empirical Bayes estimation model. Multiple linear regression analysis showed significant associations of caries prevalence with sociodemographic characteristics such as the proportion of residents with university degrees, total fertility rate, and the proportion of workers in the manufacturing industry (p < 0.001). Annual frequency of topical fluoride application showed a significant but relatively weak association with caries prevalence (p < 0.001), explaining only 0.8% of the total variation in caries prevalence, whereas no correlation was found between caries prevalence and annual frequency of dental health education. It was concluded that the effect of the fluoride application service on caries prevalence in 3-year-old children, although statistically significant, was of far lower clinical significance than sociodemographic characteristics.     

Evaluation of mutans streptococci in plaque and saliva: correlation with caries development in preschool children

OBJECTIVES: To test the ability of a site-specific method of evaluating mutans streptococci (MS) present in plaque in order to predict caries risk in children and to compare the results with those obtained from estimating the levels of MS present in saliva. METHODS: Caries prevalence was examined twice, 6 months apart, in 129 preschool children ranging in age from 1.5 to 5. A commercial strip method was used to evaluate the MS score (0-3) in plaque collected from four selected tooth surfaces at two interdental spaces and in saliva. RESULTS: The screening criteria of the MS score for caries incidence between scores 1 and 2, and scores 0 and 1 were the most valid for evaluating plaque (accuracy of prediction, 80%) and saliva (accuracy of prediction, 71%), respectively. Based on these screening criteria, the evaluation of saliva MS was invalid when the plaque MS score was considered. Screening plaque MS was effective, regardless of caries experience at baseline, according to the chi-square test (p<0.01), but screening saliva MS was ineffective when caries experience was present at baseline. A multivariate logistic regression analysis including six variables showed that the plaque MS score and caries experience at baseline were significantly correlated with caries incidence: caries experience at baseline (OR=5.02, 95%CI: 1.81-14.59) and high plaque MS score (2 or 3) (OR=12.59, 95%CI: 3.18-67.08). CONCLUSIONS: These results suggest that the semi-quantitative evaluation of plaque MS sampled from only two proximal sites on the molars is more effective for screening preschool children at a high risk of developing caries in their primary dentition than other important caries risk indicators.     

Maternal caries incidence and salivary close-contacts with children affect antibody levels to Streptococcus mutans in children

Serum and salivary immunoglobulins and antibodies reactive with Streptococcus mutans were determined in 67 5-8-year-old children. The children of mothers whose caries incidence rates exceeded the median value had significantly more serum IgG antibodies to S. mutans than those with a lower maternal caries activity (p less than 0.05). The children (n = 14) who had been exposed to frequent maternal salivary close-contacts in their first year had significantly higher (p less than 0.05) serum total specific IgG antibodies but significantly lower (p less than 0.01) high-avidity IgG antibodies to S. mutans than the other children (n = 53) with less frequent close-contacts. The maternal caries incidence rates were significantly positively associated with children's dfs/DFS-indices (r = 0.41; p less than 0.001). However, the high maternal caries incidence did not increase the risk of caries in those children whose mothers' saliva contained high amounts of lactobacilli during the first nursing year, when compared with matched children with a low maternal level of lactobacilli. This was possibly due to the fact that the former children had significantly (p less than 0.05) more anti-S. mutans IgG antibodies in their sera than the latter.     

四川省6岁儿童乳恒牙患龋状况及相关性研究

目的了解四川省6岁儿童患龋情况,探讨乳磨牙患龋与第一恒磨牙患龋之间的相关性。方法参照第三次全国口腔健康流行病学抽样调查方案,在四川省3个城市、3个农村随机抽样选取调查点,共调查714名6岁儿童的患龋情况,并分析乳磨牙患龋情况与第一恒磨牙患龋情况之间的相关性。结果四川省6岁儿童乳牙患龋率为74.37%,龋均为3.94±3.93,龋齿充填率为4.96%。乳牙患龋率和龋均在男性和女性、城市和农村儿童间无统计学差异（P>0.05）,城市乳牙龋齿充填率高于农村（P<0.05）。已萌的第一恒磨牙中有2.98%患龋,充填率为7.69%。乳磨牙患龋是第一恒磨牙患龋的危险因素[P=0.001,r=0.175,OR=5.756,95%CI（1.733,19.121）],乳磨牙与第一恒磨牙的龋均呈弱相关（P<0.001,r=0.194）。结论四川省6岁儿童乳牙患龋情况较重,乳磨牙龋坏可作为临床及预防工作中预测第一恒磨牙龋坏的因素之一。     

Prevalence of dental caries and toothbrushing habits among preschool children in Khartoum State,Sudan

Background: Dental caries in preschool children remains a major dental public health problem and affects significant numbers of children in developed and developing countries. The incidence is increasing in developing countries, such as Sudan, because of lifestyle changes, absence of oral health-preventive services and inadequate access to oral health care. Objectives: This study assessed the prevalence of dental caries and toothbrushing habits among 3- to 5-year-old preschool children in Khartoum State, Sudan, and described the correlation between the mean decayed, missing and filled tooth (dmft) score for primary teeth with toothbrushing and sugar consumption. Materials and Methods: The subjects were 553 preschool children with their mothers/guardians, selected by random sampling from the kindergartens of the seven localities of Khartoum State, Sudan. Data were obtained through clinical examination using a modified World Health Organization (WHO) examination data-capture sheet and through structured administered interviews with mothers/guardians. Results: The prevalence of dental caries was 52.4%, with a mean dmft score of 2.3. There was an increase in the dmft scores with increasing age. The frequency of children who brushed their teeth regularly at least once a day was high (83.4%), lower dmft scores were associated with starting toothbrushing earlier in life and with increased frequency of brushing per day. Eating sugar-containing food was significantly associated with dmft score. Conclusions: The prevalence of dental caries was found to be high among 3- to 5-year-old preschool children, and caries experience increased with age. This was mostly associated with sugar consumption and therefore calls for educational interventions to control sugar intake. The toothbrushing habit is well established in Khartoum State, Sudan, as a large number of children were found to be brushing their teeth regularly. No significant association was found between feeding habits and dmft score.Key words: Dental caries, preschool children, dmft, toothbrushing     

Caries activity test in Mongolian and Japanese children

The main objective of this study was to investigate the relationship between a caries activity test (CAT21 Test), and caries status. The subjects of this study were 419 preschool children, of Okayama City, Japan and, of Ulaanbaatar City, Mongolia. In all, subjects were examined for dental caries using a mouth mirror and probe. Then buccal plaque samples were obtained, incubated at 37°C for 48 hours, and scored as per the manufacturer's instructions for the Cariostat method. The following results were obtained:

• 1.The caries prevalence and mean deft of the two subjects was 55.0% and 3.2 for Japanese, so 92.4% and 6.6 for Mongolians, respectively.
• 2.Results of the CAT21 Test score distribution are as follows: 14% of the Japanese, 7.6% of the Mongolians had a CAT score of 0 (very low risk), 38% of the Japanese, 12.4% of the Mongolians had a 1.0 (low risk), 16.3% of the Japanese, 17.9% of the Mongolians had a 2.0 (middle risk), 25.5% of the Japanese, 36.6% of the Mongolians had a 3.0 (high risk), and 6.2% of the Japanese, 25.5% of the Mongolians had a 4.0 (very high risk) score.
• 3.There was a statistically significant difference in the CAT21 Test scores and dental caries indices of Japanese and Mongolian preschool children (ANOVA P< 0.01, P< 0.001).

From these results, it was suggested that the CAT21 Test is useful in clinical application     

Cariogenic microorganisms and oral conditions in asthmatic children

This study evaluated the caries risk of asthmatic patients on the basis of mutans streptococci (MS) and lactobacilli levels in saliva samples as well as the index of oral hygiene and dental caries (DMFT index). The study population was composed of 80 asthmatic children, aged 3-15 years, who use specific medication, and 80 matched, healthy control children. The parents were interviewed about oral health-related factors. The World Health Organization criteria were used for dental examinations. The K?hler and Bratthal methodology was used to detect salivary MS levels and dilutions of saliva were done for lactobacilli counting. No differences between asthma and control groups were observed for caries prevalence in children aged 3-6 and 7-10 years, except in severe cases in the younger group. However, higher caries prevalence for permanent dentition was observed in 11- to 15-year-old asthmatic children. An increased dental biofilm was observed in the asthma group, as well as salivary levels of MS. No differences were observed in levels of lactobacilli. No statistical correlations were found between medication, frequency of treatment, method of consumption and caries experience, dental biofilm and salivary levels of MS or lactobacilli. However, there was a correlation between MS levels and treatment duration. The logistic regression revealed that MS level is an important risk factor for increased caries experience. Asthma should be evaluated as a risk factor for caries experience because it can increase the levels of MS and the dental biofilm.     

重庆市学龄前儿童乳牙龋状况及影响因素分析

目的 探讨重庆市3~5岁学龄前儿童乳牙患龋状况及相关影响因素,为学龄前儿童龋病的预防和干预提供相关资料。方法 参考第四次全国口腔健康流行病学调查,对重庆市4个区学龄前儿童进行抽样调查,同时对家长进行问卷调查。利用Epidata 3.1和SPSS 21.0软件进行结果录入和统计学分析。结果 共计1 350名学龄前儿童纳入调查分析,口腔检查相关数据显示乳牙龋好发牙位是上颌乳中切牙和下颌乳磨牙,乳牙患龋率为51.4%（694/1 350）,龋均为2.34,各年龄组间患龋率和龋均差异有统计学意义（P<0.01）,且二者随着年龄增长而上升（P<0.05）。除5岁组男、女龋均有统计学差异外（P<0.05）,其余患龋率和龋均在不同性别间差异均无统计学意义（P>0.05）。61.7%龋坏集中在36.1%个体口腔中。多因素Logistic回归分析显示年龄、家长的最高学历、甜饮料（包括碳酸饮料等）摄入频率、过去1年是否有牙痛或不适、是否看过牙、牙齿和口腔健康状况自评对乳牙患龋有重要影响（P<0.05）。结论 重庆地区3~5岁儿童超过半数患龋,多数龋齿集中发生在少数患儿口内。乳牙患龋与年龄、家长的最高学历、甜饮料（包括碳酸饮料等）摄入频率、过去1年是否有牙痛或不适、是否看过牙、牙齿和口腔健康状况自评有关。     

Distribution of Streptococcus mutans and Streptococcus sobrinus in saliva of Mexican preschool caries-free and caries-active children by microbial and molecular (PCR) assays

The aim of the study was to investigate the distribution of mutans streptococci (MS) infection of caries-free (CF) and caries-active (CA) preschool Mexican children by microbial and molecular assays. Eighty preschool children were divided into two groups, 40 CF and 40 CA children. Saliva samples were inoculated onto MSB to identify CFU and DNA extractions were tested by PCR. Our results indicated that there was no statistical difference (p > 0.05) between groups either in age, weight, height or sex. S. sobrinus was detected by PCR twice as much in the CA group, the difference being statistically significant (p < 0.05). dmfs index was positive correlated with S. mutans (r = 0.2941, p = 0.0081), S. sobrinus (r = 0.3384, p = 0.0021) and S. mutans-S. sobrinus (r = 0.3978, p = 0.0003). ANCOVA revealed that dmfs index had a significant effect on the distribution of CFU of S. mutans (p = 0.0118) and S. sobrinus (p = 0.03). When MSB was compared with PCR to identify MS, there was no statistical difference (p > 0.05). We conclude that S. mutans and S. sobrinus were isolated in higher numbers from CA children and those harbouring both bacteria had higher dmfs scores. PCR is a useful tool in molecular epidemiology for dental caries studies; it was effective in detecting and identifying MS from saliva in children.