Short-term use of Lacticaseibacillus rhamnosus SD11 and the oral microbiome: Low caries RCT study

OBJECTIVES

The objective of the study was to investigate the effect of short-term lozenges containing Lacticaseibacillus rhamnosus SD11 on cariogenic pathogens and on oral microbiota.

MATERIALS AND METHODS

This double-blind, randomized, controlled trial included 121 subjects and was randomly divided into the control and probiotic group. All subjects were blindly administered to receive the control- or probiotic L. rhamnosus SD11 lozenges every day for 4 weeks and then followed up for another 4 weeks.

RESULTS

After probiotic consumption, the probiotic group had significantly lower levels of Streptococcus mutans and significantly higher levels of total lactobacilli at 4 and 8 weeks compared with the baseline. The 16S rRNA sequencing revealed an increase in bacterial diversity and beneficial bacteria in the Firmicutes phylum, Bacilli class, and a reduction in the mutans streptococci group in the probiotic group. The opposite results were found in the control group. This study did not find any caries increment, nor did the subjects have any side effects after product consumption.

CONCLUSION

With the limitation of a short-time study in low caries children, it showed that L. rhamnosus SD11 could increase beneficial bacteria in the Firmicutes phylum and Bacilli class that might support good oral health in children.

Fermented milk containing a potential probiotic Lactobacillus rhamnosus SD11 with maltitol reduces Streptococcus mutans: A double-blind, randomized, controlled study

Background/purpose

Sucrose has been considered as a cariogenic substrate due to large amounts of acid production after fermentation by certain oral bacteria, thus sugar alcohols are often used to replace sucrose. The aims of this study were to investigate the effect of maltitol on the growth and acid production of Streptococcus mutans and Lactobacillus rhamnosus-SD11 compared to various sugars, and to examine whether the fermented milk containing a potential probiotic L. rhamnosus-SD11 with maltitol could reduce S. mutans.

Materials and methods

The acid production of tested sugars by cariogenic S. mutans was measured using pH meter. In a clinical trial, 123 children were recruited and randomly assigned to either the probiotic- or control-fermented milk, once daily for 4 weeks. The target bacteria levels in the saliva were examined using a real-time PCR at baseline, 4 and 8 weeks. The oral examination was recorded at the baseline and 8 weeks.

Results

The results showed that maltitol exhibited less acid production than simple sugars. In the clinical trial, a significant reduction of salivary total streptococci and S. mutans occurred, while the levels of salivary lactobacilli significantly increased in the probiotic group compared to the control group after receiving the probiotic fermented milk.

Conclusion

The daily consumption of the fermented milk containing L. rhamnosus-SD11 with maltitol had beneficial effects on oral health by reducing salivary S. mutans. Thus, the substitution of simple sugars by maltitol in dairy products containing L. rhamnosus-SD11 may be an alternative way to prevent the risk of caries.

Efficacy of Probiotic Milk for Caries Regression in Preschool Children: A Multicenter Randomized Controlled Trial

This multicenter double-blind randomized controlled trial aimed to determine the efficacy of daily or triweekly consumption of reconstituted milk powder, containing <i>Lactobacillus paracasei</i>SD1, in preschool children for caries prevention. A 6-month intervention was conducted in 487 children (aged 37.6 ± 9.2 months) with ≤4 decayed teeth from 8 childcare centers. Using stratified block randomization, participants were randomly allocated into 3 groups, comprising: (1) daily probiotic, receiving probiotic milk once daily, (2) triweekly probiotic, randomly receiving probiotic milk 3 days a week and the placebo milk for the remaining 4 days, and (3) placebo, receiving milk without probiotics. Each tooth surface was assessed for caries status using the modified Nyvad criteria at baseline (T0), 6 (T6) and 12 (T12) months after T0. Study outcomes were caries transition, including caries progression and regression during the T0–T6, T6–T12 and T0–T12 periods. Negative binomial regression with a generalized linear model was used to estimate the caries outcomes, which were reported as incidence rate ratios (IRRs) and 95% confidence intervals (CIs). At baseline, caries prevalence and mean decayed surfaces were 81.9% and 7.29 ± 7.60, respectively. Three groups were balanced at baseline with an overall dropout rate of 25.2%. After adjusting for age, sex, and the number of noncavitated and cavitated caries at baseline, a decreased caries risk during T0–T6 was shown in both the daily and triweekly probiotic groups (adjusted IRR 0.83, 95% CI 0.72–0.96 in both groups) and during T0–T12 (adjusted IRR 0.84, 95% CI 0.76–0.94, and adjusted IRR 0.86, 95% CI 0.76–0.96, respectively) compared to the placebo group. In contrast, significantly increased regressive surfaces were demonstrated during T0–T6 by adjusted IRR 1.76 (95% CI 1.25–2.48) and 2.01 (95% CI 1.42–2.85) and during T0–T12 by adjusted IRR 1.98 (95% CI 1.50–2.61) and 1.92 (95% CI 1.45–2.55) for the daily and triweekly groups, respectively. In conclusion, probiotic milk consumption either daily or triweekly can modestly prevent new caries, but considerably reverse carious lesions, suggesting that a daily or triweekly dose interval is sufficient to reverse carious lesions.

Significant elevation of salivary human neutrophil peptides 1-3 levels by probiotic milk in preschool children with severe early childhood caries: a randomized controlled trial

OBJECTIVES

To determine salivary human neutrophil peptides 1-3 (HNP1-3) levels in caries-free preschool children and in those with early childhood caries (ECC) or severe-ECC, in a daily probiotic group, receiving reconstituted milk with the probiotic Lactobacillus paracasei SD1 once daily; a triweekly probiotic group, receiving the probiotic milk 3 days a week; and a placebo group.

MATERIALS AND METHODS

Oral examination and unstimulated whole saliva collection were conducted in 354 children at baseline, 6 months after intervention (T6), and after probiotic discontinuation (T12). Of the 354, adequate volume of saliva samples from 268 children were simultaneously analyzed for Streptococcus mutans and total lactobacilli levels using qPCR and for HNP1-3 levels using ELISA.

RESULTS

In the severe-ECC status, significant increases in the median HNP1-3 levels at T12 were found in both daily and triweekly probiotic groups (p < 0.001). The median S. mutans levels in the daily group were significantly decreased at T6 and T12 (p < 0.01), whereas the median total lactobacilli levels were significantly increased at T6 (p < 0.001). Significantly inverse correlations between altered HNP1-3 and S. mutans levels and significant decreases in caries progression were found in both probiotic groups (p < 0.05).

CONCLUSIONS

In the severe-ECC status, daily or triweekly consumption of L. paracasei SD1 significantly enhanced salivary HNP1-3 levels, but reduced S. mutans levels, possibly resulting in reduction of caries progression.

CLINICAL RELEVANCE

Significant enhancement of salivary HNP1-3 levels by probiotic consumption is associated with reduction in S. mutans levels, consistent with diminished caries progression in children with severe-ECC.

Impact of Potential Probiotic Lactobacillus Strains on Host Growth and Development in a Drosophila melanogaster Model

Lactobacillus paracasei SD1, Lactobacillus rhamnosus SD11, and Lactobacillus gasseri SD12 were proposed as potential probiotics for oral health. However, the effects of them on host physiology are still unknown. This study aimed to select strains that can promote host growth and development in monocolonized Drosophila model compared with axenic and the commercial Lactobacillus rhamnosus GG-treated flies. The morphogenesis and growth of axenic Drosophila melanogaster were assessed from embryo to adult stage when provided with each probiotic strain-supplemented food. The colonization and persistence of probiotic in fly gut were also evaluated. The results indicated that axenic condition caused the lowest adult weight and emergence rate. All probiotic groups had higher weight than axenic group. Lact. rhamnosus SD11 group presented high adult emergence rate equivalent to Lact. rhamnosus GG group, which is significantly higher than the others. However, Lact. gasseri SD12 group had significantly lower adult weight and emergence rate when compared with Lact. rhamnosus GG group. The gut probiotics levels were rapidly increased within the first day after receiving probiotics. After probiotic cessation, their number in gut decreased and was maintained at low level, except for Lact. gasseri SD12, which completely vanished since day one. In conclusion, Lact. paracasei SD1, Lact. rhamnosus SD11, and Lact. rhamnosus GG can affect morphogenesis and weight of flies when fed since immature stage and have short period gut colonization. The findings of this study could possibly imply comparable health-promoting effects between Lact. paracasei SD1 and Lact. rhamnosus SD11 to commercial strain in Drosophila model.

Associations Between Temperament and Dental Caries Status in Thai Children

PURPOSE

To examine the relationships between (1) the levels of each temperament traits and the levels of milk-feeding frequency, oral hygiene care and dental caries, and (2) the difference in mean numbers of decayed surfaces among temperament types.

MATERIALS AND METHODS

Four hundred and ninety-three (493) 12-month-old infants were assessed for temperaments and characteristics of child-rearing practices. The data were analysed with their dental caries status at 18 months of age. The chi-squared test, Student's t test, ANOVA and Kruskal-Wallis tests were used to assess the association between temperament traits and the following variables; dental caries, oral cleaning habits and feeding frequency. Logistic regression models were used to identify the effect of temperament traits and other factors on dental caries status.

RESULTS

The trait of adaptability was found to associate with feeding frequency at night, while those of activity and approach/withdrawal were significantly associated with regularity of oral cleaning habits by the children's caregiver. Three of the nine temperament traits - biological rhythmicity, approach/withdrawal and mood - were significantly associated with dental caries in bivariate analysis. Biological rhythmicity and approach/withdrawal traits were significantly associated with a higher chance of having caries after adjusting for regularity of oral cleaning habits and frequency of night feeding.

CONCLUSION

Biological rhythmicity, approach/withdrawal and mood traits were related to caries in these young children.

Reduction of Streptococcus mutans by probiotic milk: a multicenter randomized controlled trial

OBJECTIVE

To investigate the effects of probiotics, Lactobacillus paracasei SD1, on the quantities of Streptococcus mutans in saliva and plaque samples of preschool children.

DESIGN

This randomized trial recruited 487 preschool children from eight childcare centers. Participants were assigned to receive a 6-month course of placebo milk daily (group I), probiotic milk either daily (group II) or three days a week (triweekly, group III). The absolute quantities of S. mutans and total lactobacilli in the saliva and plaque samples at baseline (T0), after intervention (T6), and 6 months after discontinuation (T12) were assessed by qPCR.

RESULTS

Of 487 children, 354 completed all follow-up periods. However, only 268 children (3.2 ± 0.8 years old; groups I = 86, II = 89, and III = 93) provided adequate saliva for qPCR. Whereas the quantities of S. mutans were significantly decreased in groups II and III compared to group I in the saliva and plaque samples at T6 and T12, those of total lactobacilli were significantly increased (p < 0.0167). There was no difference in the quantities of S. mutans or total lactobacilli between groups II and III at any period. Significant changes in the quantities of S. mutans and total lactobacilli lasted until T12 compared to T0 (p < 0.0167).

CONCLUSIONS

Probiotic administration daily or triweekly reduces S. mutans quantities, whereas it increases total lactobacilli quantities that persists at least 6 months after discontinuation in the saliva and plaque samples of preschool children.

CLINICAL RELEVANCE

Daily or triweekly consumption of L. paracasei SD1 supplemented in milk may help prevent dental caries in preschool children.

Increasing salivary IgA and reducing Streptococcus mutans by probiotic Lactobacillus paracasei SD1: A double-blind, randomized, controlled study

Background/purpose

Our previous study revealed that probiotic Lactobacillus paracasei SD1 could reduce mutans streptococci as evaluated by cultivation-method as well as stimulate innate immunity. This study aimed to further investigate the effect of the probiotic on various oral bacteria by real-time PCR and salivary IgA levels.

Materials and methods

Forty children were included by randomization from either probiotic or control group in the previous study. The probiotic or control received milk-powder with or without L. paracasei SD1, respectively once daily for 6 months. Saliva were collected at baseline 3-, 6-, and 12-months and were evaluated for total bacteria, total lactobacilli (TL), L. paracasei/L. casei (LP/LC), total streptococci (TS) and Streptococcus mutans using the real-time PCR. The salivary IgA (sIgA) was examined using the ELISA method.

Results

All target bacterial levels were not significantly different at baseline in both groups. After milk-powder consumption, TL and LP/LC levels were significantly increased in the probiotic group, whereas TS and S. mutans levels were significantly decreased compared to baseline. TS and S. mutans levels were significantly lower, while the sIgA was greater in the probiotic compared to the control group. In the probiotic group, a positive correlation was found between LP/LC and sIgA, while negative correlations were observed between TS or S. mutans levels and sIgA.

Conclusion

L. paracasei SD1 could control S. mutans level and could stimulate sIgA. Results indicate that the L. paracasei SD1 strain may have a benefit for prevention of dental caries.

Reducing mutans streptococci and caries development by Lactobacillus paracasei SD1 in preschool children: a randomized placebo-controlled trial

OBJECTIVE

To examine a reducing effect of Lactobacillus paracasei SD1 on MS and caries in preschool children.

MATERIALS AND METHODS

A total of 124 children, aged 1.5-5 years old, participated and were randomly assigned to the probiotic or control group. The probiotic group received L. paracasei SD1-milk and the control group received standard-milk once daily for 3 months. MS/lactobacilli were enumerated and the caries score was examined. Association between probiotic consumption and bacterial level, or caries progression was assessed by a multivariate logistic regression. This study was registered at the Thai-Clinical-Trials-Registry (TCTR20140903001).

RESULTS

Probiotic was found to be a factor associated with the MS level. Children in the probiotic group had a significantly lower risk of an increase in the MS level than in the control group after receiving the probiotic milk at 3- and 4-months with p < .001 and p = .040, respectively. Probiotic significantly reduced the risk for caries compared to the control group (p = .016). There were no adverse effects or non-compliance reported in either group.

CONCLUSIONS

Consumption of milk powder containing L. paracasei SD1 resulted in a reduction of both salivary MS and delayed new caries development, and the strain is safe for use in young children. Results suggest that L. paracasei SD1 may be an alternative way for caries prevention in young children.

Effect of fermented milk containing Lactobacillus rhamnosus SD11 on oral microbiota of healthy volunteers: A randomized clinical trial

The aims of this study were to evaluate whether short-term consumption of fermented milk containing Lactobacillus rhamnosus SD11 affected levels of oral microbiota in vivo and whether L. rhamnosus SD11 could colonize in the human mouth. We also monitored for potential side effects of the probiotic. The applicability of using L. rhamnosus SD11 compared with Lactobacillus bulgaricus as a starter culture for fermented milk was evaluated. After informed consent, 43 healthy young adults were recruited and randomly assigned to either the probiotic or control group and received fermented milk containing L. rhamnosus SD11 or L. bulgaricus, respectively, once daily for 4 wk. The numbers of mutans streptococci, lactobacilli, and total bacteria in saliva were counted at baseline and then after 4 and 8 wk. An oral examination was performed at baseline and after 8 wk. The persistence of L. rhamnosus SD11 was investigated by DNA fingerprinting using arbitrary primer-PCR. Results demonstrated that statistically significant reductions in mutans streptococci and total bacteria were observed in the probiotic group compared with the control group, and the number of lactobacilli was significantly increased in both groups after receiving fermented milks. Lactobacillus rhamnosus SD11 could be detected (in >80% of subjects) up to 4 wk following cessation of dosing among subjects in the probiotic group. No side effects were reported. Thus, L. rhamnosus SD11 could be used as a starter culture for fermented milk. Daily consumption of L. rhamnosus SD11-containing fermented milk for 4 wk may have beneficial effects on oral health by reducing salivary levels of mutans streptococci. The probiotic was apparently able to colonize the oral cavity for a longer time than previously reported. However, the potential benefits of probiotic L. rhamnosus SD11 on oral health require further evaluation with a larger group of volunteers in a longer-term study.

Assessment of Prevalence, Adhesion and Surface Charges of Bifidobacterium spp. Isolated from Thai Women with Bacterial Vaginosis and Healthy Women

BACKGROUND

Bifidobacterium spp. have been reported in women with bacterial vaginosis (BV), nevertheless data of prevalence and adhesion property of the vaginal bifidobacteria in Thai women with BV are still limited.

OBJECTIVE

To determine prevalence of Bifidobacterium spp. and to evaluate adhesion ability and cell surface properties of bifidobacterial isolates from Thai women with BV compared to healthy subjects.

MATERIAL AND METHOD

A total of 139 bifidobacterial isolates from 20 of 60 women with BV and 7 of 60 healthy women. The isolated strains were identified by molecular biology techniques and examined for adhesion property and surface charges.

RESULTS

The prevalence of vaginal bifidobacteria in women with BV (33.3%) was significantly (p<0.05) higher than healthy women (11.7%) with total counts of 8.9±3.4 Log CFU/ml and 5.7±2.9 Log CFU/ml, respectively. The frequent species of B. bifidum, B. longum, B. breve and B. dentium were found in women with BV, while healthy women harbored B. bifidum, B. longum and B. breve. All vaginal bifidobacteria from BV and healthy subjects were able to adhere cultured cells in vitro. The adhesion ability of B. bifidum and B. dentium from BV subjects showed high degree of adhesion property and was in correlation with cell surface characteristics.

CONCLUSION

The prevalence of vaginal bifidobacteria occurred significantly higher in women with BV than healthy group. The strains of B. bifidum and B. dentium showed high adhesion property which implied as an important role of colonization in vaginas of women with BV.

Purification, Characterization, and Optimum Conditions of Fermencin SD11, a Bacteriocin Produced by Human Orally Lactobacillus fermentum SD11

Fermencin SD11, a bacteriocin produced by human orally Lactobacillus fermentum SD11, was purified, characterized, and optimized in conditions for bacterial growth and bacteriocin production. Fermencin SD11 was purified using three steps of ammonium sulfate precipitation, gel filtration chromatography, and reverse-phase high-performance liquid chromatography. The molecular weight was found to be 33,000 Da using SDS-PAGE and confirmed as 33,593.4 Da by liquid chromatography-mass spectrometry. Fermencin SD11 exhibited activity against a wide range of oral pathogens including cariogenic and periodontogenic pathogens and Candida. The active activity was stable between 60 - 80 °C in a pH range of 3.0 to 7.0. It was sensitive to proteolytic enzymes (proteinase K and trypsin), but it was not affected by α-amylase, catalase, lysozyme, and saliva. The optimum conditions for growth and bacteriocin production of L. fermentum SD11 were cultured at acidic with pH of 5.0-6.0 at 37 or 40 °C under aerobic or anaerobic conditions for 12 h. It is promising that L. fermentum SD11 and its bacteriocin may be an alternative approach for promoting oral health or prevention of oral diseases, e.g., dental caries and periodontitis, which would require further clinical trials.

Aggregatibacter actinomycetemcomitans serotypes and DGGE subtypes in Thai adults with chronic periodontitis

OBJECTIVE

To investigate the distribution of Aggregatibacter actinomycetemcomitans serotypes and DGGE subtypes among isolates from Thai chronic periodontitis patients.

DESIGN

Forty-four adult Thai periodontitis patients were assessed by a full mouth recording for CAL, PPD, and BOP. Seventy-nine strains of A. actinomycetemcomitans were isolated from deep pockets on selective TSBV agar and 17 strains were isolated from shallow pockets. The strains were serotyped using PCR and subtyped using DGGE.

RESULTS

The prevalence of A. actinomycetemcomitans was 84.1%. Non-serotypeable A. actinomycetemcomitans strains occurred equally frequent as serotypeable (54.5%); serotype a 18.2%, serotype c 15.9%, serotype e 9.1%, and serotype f 11.4%. Serotype b and d were not detected. A JP2 like strain but serotyped as c was isolated from two patients, and another two strains showed an 886bp insertion on the ltx promoter of their A. actinomycetemcomitans isolates. DGGE typing disclosed 16 different subtypes among the non-serotypeable strains. Two of them (NS1 and NS2) were more common (12.7 and 10.1%) among the strains than the other 14 subtypes (˂5.1%). Most patients showed only one subtype (32.4%) but 29.7% had 2 and 3 different subtypes while 8.1% revealed 4 subtypes in one and the same deep pocket.

CONCLUSION

This study showed a greater subtype diversity of A. actinomycetemcomitans predominated by non-serotypeable strains than previously reported in an adult Thai population. It was also revealed for the first time that isolates with a 530bp deletion or 886bp insertion of the ltx promoter were serotyped as serotype c.

Enhancement of salivary human neutrophil peptide 1-3 levels by probiotic supplementation

Background

Probiotic supplementation can reduce mutans streptococci (MS) numbers. One of its proposed mechanisms is immunomodulation. Salivary human neutrophil peptide 1–3 (HNP1-3) levels have previously been demonstrated to be higher in caries-free than in caries-susceptible children, suggesting their preventive role against caries. We aimed to compare salivary HNP1-3 levels between an intervention group with probiotics and a control group.

Methods

A randomized double-blinded clinical trial was conducted. Sixty schoolchildren were equally allocated to either an intervention or control group. The use of a probiotic strain, Lactobacillus paracasei SD1, has shown to reduce MS numbers in volunteers. In unstimulated whole saliva, HNP1-3 levels were assayed by ELISA, and MS and lactobacilli counts were assayed by colony counting at baseline (T0) and at 3 (T3), 6 (T6), and 12 months (T12). The International Caries Detection and Assessment system was used to assess caries status.

Results

In the intervention group, salivary HNP1-3 levels were significantly greater than those in the control group at T3 and T6 (p < 0.001), whereas MS counts were significantly decreased (p < 0.01). In the intervention group, positive and negative correlations were found between HNP1-3 levels and lactobacilli counts and between MS and lactobacilli counts, respectively. However, there was no significant correlation between enhanced HNP1-3 levels and decreased MS numbers. The caries increment for the pit and fissure surface, but not for the smooth surfaces, was significantly decreased in the intervention group compared with the control group (p = 0.01).

Conclusions

Probiotics can temporarily enhance salivary HNP1-3 levels; however, their action to reduce new pit and fissure caries probably involves microbial interactions.

Trial registration

TCTR20130904001 (registration date: September 04, 2013).

Electronic supplementary material

The online version of this article (doi:10.1186/s12903-015-0003-0) contains supplementary material, which is available to authorized users.

Purification and characterization of bacteriocin produced by oral Lactobacillus paracasei SD1

The present study aimed to purify and characterize the antimicrobial protein from Lactobacillus paracasei SD1, which is a strain from the human oral cavity. Antimicrobial activity was obtained from purifying the culture supernatant of L. paracasei SD1. Purification of the active compound was achieved with ammonium sulfate precipitation followed by chloroform and gel filtration chromatography. As revealed by SDS-PAGE, the active fraction was homogeneous, showing a protein with an approximate molecular weight of 25,000 Da. It was confirmed as having a molecular mass of 24,028.2 Da by mass spectrometry. The antimicrobial compound, named "paracasin SD1", exhibited a broad spectrum against oral pathogens. Paracasin SD1 was stable in a pH range between 3.0 and 8.0 at 100 °C for 5 min, and showed resistance to α-amylase, catalase, lysozyme and whole saliva. However, its activity was lost after proteinase K and trypsin treatment. The results obtained suggest the possibility of using paracasin SD1 for application in prevention/treatment of oral diseases.

Prevalence of lactobacilli in normal women and women with bacterial vaginosis

OBJECTIVE

To study the prevalence and the number of lactobacilli in normal subjects and in women with bacterial vaginosis (BV).

MATERIAL AND METHOD

The studied subjects consisted of 60 normal and 60 BV women. The diagnosis of BV was based on at least three of five indicators of Chandeying criteria. The vaginal specimens were collected and cultured on MRS plates for determination of lactobacilli counts.

RESULTS

The number of lactobacilli was highly significant (p < 0.001) in the women with diagnosis of BK and the mean count of lactobacilli in BV was markedly decreased (5.3 +/- 1.8 log colony-forming unit--CFU/ml), compared with normal women (8.8 +/- 2.9 log CFU/ml). Among the treated BV group, follow-up vaginal specimen was encountered in 47 of 60 cases (78.3%). The proportion of lactobacilli isolation was slightly increased from 12 (25.5%) to 15 (31.9%) in 47 cases. Concordance with quantitative settlement of lactobacilli in BV was increased from 1.4 +/- 2.6 log CFU/ml, to 1.8 +/- 2.9 log CFU/ml in treated BV. Treated BV the lactobacilli had not restored significance (p = 0.5831), as well as the total bacteria.

CONCLUSION

Lactobacilli dominantly occur in healthy women, and markedly decline in BV. However, the vaginal ecosystem is dynamically changed in the lactobacilli of either normal or BV women.

Vertical transmission of mutans streptococci and lactobacillus in Thai families

PURPOSE

The purpose of this study was to investigate the vertical transmission of mutans streptococci (MS) and lactobacilli in a group of Thai families.

METHODS

One hundred eighty-one mother-child pairs were included in this study. Unstimulated saliva was collected using the spatula method and counted for evaluating the number of MS and lactobacilli on a selective medium. Genotyping of MS and Lactobacillus species were performed in 37 and 22 child-mother pairs, respectively. Typically, 3 to 4 isolates of MS and/or Lactobacillus strains from each mother and child were collected for genotyping by an arbitrarily primed polymerase chain reaction (OPA-02 primer for MS and enterobacterial repetivive intergenic consensus primers for Lactobacillus species).

RESULTS

Generally, MS and lactobacilli levels in children were associated with their mothers' levels. Genotyping of most isolates of MS and Lactobacillus strains in both mothers and children found diversity, and each individual showed a distinct genotypic pattern. The presence of matching genotypes of MS and Lactobacillus strains of mother-child was approximately 76% and 50%, respectively. The genotypes acquired from the maternal route show effective persistence in the children's oral cavities.

CONCLUSIONS

In Thai families, mothers can be the source for transmission of mutans streptococci and Lactobacillus strains to their children.

Lactobacillus species and genotypes associated with dental caries in Thai preschool children

Lactobacilli have been associated with the presence and progression of dental caries. Nevertheless, the relation between certain species or genotypes of Lactobacillus and caries is unclear and there are no data available for the Thai population. This study aimed to examine the distribution of species and genotypes of oral Lactobacillus among children with rather high caries prevalence, and to investigate whether certain species or genotypes were more related to caries activity than others. One hundred and sixty-five children were examined for caries status. Saliva samples were collected and the numbers of lactobacilli were counted. A total of 357 Lactobacillus isolates from 59 children were identified to species level by 16S ribosomal RNA genes polymerase chain reaction (PCR) -restriction fragment length polymorphism and 16S ribosomal RNA gene sequencing. Furthermore, 304 isolates from 56 children were genotyped using arbitrarily primed PCR. Significant correlation was found between levels of lactobacilli and dental caries (P < 0.001). Among the 10 identified species of Lactobacillus, L. salivarius was more prevalent in children with moderate to high caries prevalence compared with children with low caries prevalence, while L. fermentum was the most predominant species in all study groups. Moreover, a genetic heterogeneity of Lactobacillus species was found among the children and those with high caries prevalence tended to be colonized with more than one clonal type. In summary, L. salivarius may be a putative caries pathogen among preschool Thai children.

A microbiological study in relation to the presence of caries and calculus

OBJECTIVE

To examine whether oral microflora in individuals with caries differs from that of individuals with calculus in Thai adolescents with poor oral hygiene.

MATERIAL AND METHODS

One hundred 13-year-old schoolchildren from Southern Thailand were examined for the presence of caries, calculus and plaque and saliva pH was also determined. Saliva samples were analysed by culture and approximal supragingival plaque samples were analysed with the DNA-DNA hybridization method ('checkerboard').

RESULTS

Among the 100 children, mean DMFS was 3.43 [standard deviation (SD) 2.82] and 90% had calculus. The correlation between DMFS and the calculus index was 0.064. A total of 36 children were caries-free and 56 had calculus including teeth other than those in the lower anterior region (calculus score > or =3). A total of 23 caries-free children with a high calculus score (> or =3) were compared with 22 children with the highest DMFS [mean 11.19 (SD 5.58)] and a calculus score < 3. No significant difference was obtained for saliva and plaque pH. The salivary levels of mutans Streptococci and Lactobacilli were low. Significantly more children in the caries group had high levels of glycolytic Prevotella nigrescens and Filifactor alocis in plaque compared with the calculus group. Calculus cases had a significantly higher total viable count in saliva.

CONCLUSIONS

There was no inverse correlation between the presence of caries and calculus at a population level and a high calculus score only marginally reduced the individual likelihood of having caries. Several glycolytic bacteria were related to caries, while no specific bacteria could be related to calculus formation. Calculus seemed to be more closely related to poor oral hygiene.

Partial pulpotomy on caries-free teeth using enamel matrix derivative or calcium hydroxide: a randomized controlled trial

AIM

To compare the effect of enamel matrix derivative (EMD) and calcium hydroxide [Ca(OH)(2)] on exposed human pulp.

METHODOLOGY

Fifteen pairs of human contralateral premolars were intentionally and partially pulpotomized. The exposed pulps were randomly capped with either EMDgel (Emdogain) or a mix of Ca(OH)(2) and sterile water. The subjects recorded pain or discomfort during the first 10 days and were also interviewed and examined by a blinded examiner at 1 day, 2 weeks, 3 and 6 months post-operation. Periapical radiographs were taken prior to the operation, and 3 and 6 months post-operation. After 6 months, the teeth were extracted and processed for histological evaluation. The data were described and analysed using McNemar test and Kaplan-Meier survival analysis.

RESULTS

The EMDgel-treated teeth had significantly less tooth hypersensitivity than the Ca(OH)(2)-treated teeth during the first 2 weeks (P = 0.031) but were not significantly different after 2 weeks (P = 0.125). No detectable periapical radiographic changes were observed in any teeth and radiographic evidence of dentine bridge formation from both groups were not significantly different during the follow-up periods (P > 0.05). Histological evaluation demonstrated that the Ca(OH)(2)-treated teeth had less inflammation and more dentine bridge formation than those in the EMDgel-treated teeth.

CONCLUSIONS

After 6 months, healthy pulps capped with Ca(OH)(2) had more favourable results than counterparts capped with EMDgel. However, similar clinical and radiographic results were seen in both groups.

Risks for Early Childhood Caries Analyzed by Negative Binomial Models

Because of the high incidence of early childhood caries (ECC), a longitudinal study to identify risk factors from the prenatal period to the child’s first birthday among 9- to 18-month-old children was conducted with negative binomial modeling. Overall, 495 children had dental examinations at ages 9, 12, and 18 months. Mothers were interviewed during the 2nd trimester of pregnancy and when the children had dental examinations. The highest incidence of caries was found among children who were born to mothers with ≥ 10 decayed teeth and who never received calcium supplements during pregnancy, and children who were not fed supplementary foods at age 3 months, had sweet-tasting foods at 5 months, started snacking at 5 months, had sugary snacks, had soft drinks, and did not have their teeth brushed daily at 9 months. Thus, prenatal care and child-rearing-practices during and after birth are important risk factors for the incidence and incremental rate of ECC.

Longitudinal study of the presence of mutans streptococci and lactobacilli in relation to dental caries development in 3-24 month old Thai children

OBJECTIVE

To study the acquisition of mutans streptococci (MS) and lactobacilli in relation to dental caries development in 3-24 month old Thai children.

METHODS

Salivary samples were collected from 169 children using sterile wooden tongue depressors at the ages of 3, 9, 12, 18 and 24 months. The blades were pressed onto selective media for MS or lactobacilli. After incubation, the colony forming units of MS/lactobacilli were counted. Dental status was recorded from 9 months old using modified WHO criteria.

RESULTS

The number of children with caries and number and severity of decayed teeth significantly increased with age. The presence of MS/lactobacilli was detectable at an early age and the cumulative prevalence of MS/lactobacilli increased with age. Children who were colonised early by MS or lactobacilli showed a higher number of decayed teeth than of those who were colonised later. The children with no MS/lactobacilli had significantly fewer decayed teeth and there was a significant correlation between MS/lactobacilli level and tooth decay.

CONCLUSIONS

This longitudinal study shows early colonisation of the mouths of Thai children by MS/lactobacilli and where there are persistently high levels of the bacterias increased risk of development of dental caries.

A longitudinal study of early childhood caries in 9- to 18-month-old Thai infants

OBJECTIVE

To examine the rate and pattern of early childhood caries (ECC) development and to investigate the transitional changes of the carious lesions during a follow-up period of 3-9 months.

METHODS

A longitudinal observational community-based survey of 599 children, 9-18 months old. The children's dental examinations were first carried out at the age of 9 months with re-examination at 12 and 18 months by five dentists using standardized methods. The affected rates of dental caries were determined for prevalence, incidence density for risk of caries per person (IDp) and risk by surface (IDs). Changes in dental status over time were explored from unerupted (U) to sound (S), including enamel caries (D1), dentine caries (D2) and caries involving pulp (D3) by computing transitional probabilities.

RESULTS

The prevalence of caries was 2.0%, 22.8% and 68.1% among 9-, 12- and 18-month olds, respectively. The IDp observed for newly affected children 9-12 and 12-18 months old was 10.32 and 15.70 persons/100 person-months, respectively. The IDs for children 9-12 months old was 2.17 newly affected surfaces/100 surface-months whereas it was 2.22 surfaces/100 surface-months for children 12-18 months old. The buccal surface of maxillary incisors was the most affected (44.9%) followed by lingual, mesial and distal surfaces, respectively. The transitional probability of caries progression ranged between 1.79% and 15.38% during the follow-up period from 9 to 12 months old. It was 3.43-39.60% from 12 to 18 months old.

CONCLUSIONS

An extremely high caries-affected rate was found among the study children even before the age of 18 months. The buccal surface of the maxillary incisors was the most affected. The teeth acquired caries at 3-6 months after initial eruption and carious lesions developed continuously over time.

Comparative clinical evaluation of slot versus dovetail Class III composite restorations in primary anterior teeth

This study compares the clinical characteristic evaluations of slot against dovetail class III composite restorations. Focusing on the primary anterior teeth of children aged 2 years 6 months to 5 years 3 months with the mean age of 4 years, thirty-six matched pairs of class III of slot and dovetail preparations were made by one investigator These preparations were evaluated for marginal adaptation, anatomic form, secondary caries and marginal discoloration after 6, 12, and 24 months by another investigator with the intra-examiner reliability of 0.95 - 1 (Kappa Statistic). The results revealed no statistical significance in the difference of clinical characteristics between the two designs (p > 0.05).