Salivary Microbial Counts Research Articles

Effects of Different Types of Probiotics on Microbial Colonization in Saliva of Orthodontic Patients—In Vivo Study

Introduction Streptococcus mutans and Lactobacillus count is found to be higher in orthodontic patients and is one of the leading causes of white spot lesion formation. Probiotics are emerging as alternative methods of plaque control. Aims and Objectives To determine the effects of different types of probiotics on S. mutans and Lactobacillus levels in saliva of orthodontic patients. Materials and Methods A total of 140 subjects were divided into Control group (Group I) with 20 subjects and study group taking probiotics (Group II) with 120 subjects. Saliva samples were taken at baseline ( T0), after three weeks ( T1), and after six weeks ( T2). The samples were diluted and incubated on specific agar media plates. The colonies observed were expressed in colony forming units per milliliter (CFU/ml) of saliva. Group II was further subdivided into six subgroups based on probiotic intake with 20 subjects in each subgroup. Results Statistically significant difference was found in salivary microbial counts in all the probiotic groups ( p < 0.05). The highest reduction in count of S. mutans (653.00 ± 102.23 CFU/ml to 84.1 ± 30.48 CFU/ml) and Lactobacilli (87.35 ± 15.64 CFU/ml to 14.60 ± 8.28 CFU/ml) was seen in the lozenges group. Conclusion Probiotics decrease the number of salivary S. mutans and Lactobacilli and lozenges could be considered for orthodontic fixed appliance patients.

Effectiveness of Mouthwash-Containing Silver Nanoparticles on Cariogenic Microorganisms, Plaque Index, and Salivary pH in A Group of Saudi Children

Objectives:To compare the effectiveness of Silver nanoparticles (AgNPs) and Chlorhexidine (CHX) mouthwash onStreptococcus mutans (S. mutans),Lactobacillus spp., andCandida albicans(C. albicans) counts O’Leary plaque index (O’Leary PI) scores, and salivary pH levels among children.Materials and Methods:The study sample consisted of 117 eligible participants aged 12–18 years. They were divided into control, CHX, and AgNPs groups, with 39 subjects per group. The log10salivary microbial counts, O’Leary PI, and salivary pH values were recorded and statistically analyzed at baseline and the 28thday. Descriptive statistics were presented as the mean ± standard deviation. In addition, the analyses of variance (ANOVA) and Tukey posthoc test were implemented. Thep-value ≤ 0.05 denotes a significant difference between the two points.Results:AgNPs and CHX mouthwash were found to have significantly reduced salivary microbial counts and O’Leary PI scores. The salivary pH levels notably increased on the 28thday (p-value < 0.001). All measured outcomes demonstrated notable effects, with the greatest observed for the CHX group, followed by the AgNPs group, and finally, the control group.Conclusion:Chlorhexidine and AgNPs mouthwash effectively reduced the cariogenic microbial count and dental plaque and improved the salivary pH values. AgNPs mouthwash may be used as an adjunctive measure to prevent dental caries.

Dental caries prevalence among Type 1 diabetes mellitus (T1DM) 6- to 12-year-old children in Riyadh, Kingdom of Saudi Arabia compared to non-diabetic children

ObjectiveThe aim of this study was to compare the prevalence of dental caries among groups of 6–12-year-old children with and without Type 1 diabetes mellitus (T1DM) in Riyadh, Saudi Arabia, taking into account oral health behaviour, diet, and salivary parameters. MethodsThe study was designed as a comparable study of dental caries experience between T1DM and non-diabetic groups of children. The total sample size of 209 participants consisted of 69 diabetic and 140 non-diabetic children. Oral hygiene, diet and socio-economic status were collected using a pre-tested questionnaire. Caries was recorded in terms of decayed and filled permanent and primary teeth (DFT/dft). Salivary microbial counts and pH levels were recorded using Caries Risk Test (CRT) kit. Student's t-test, the chi-squared test, linear regression and one-way analysis of variance were performed P-value of 0.05 considered significant. ResultsThe mean dft scores for the diabetic and non-diabetic groups were 3.32 ± 0.78 and 3.28 ± 0.71 (mean ± SD), respectively (p = 0.458). The mean DFT scores for the diabetic and non-diabetic groups were 1.62 ± 0.65 and 1.96 ± 0.65, respectively (p = 0.681). Diabetic children visited dentists more often than non-diabetic children did (p = 0.04), and had lower consumption of both sweets (p = 0.003) and flavoured milk (p = 0.002) than the non-diabetic group. Furthermore, analysis showed that the diabetic children had medium oral pH levels (pH = 4.5–5.5), whereas the non-diabetic children tended to have high (pH ≥ 6.0) oral pH; this difference was statistically significant (p = 0.01). In addition, the diabetic group had higher Lactobacillus levels than the non-diabetic group (p = 0.04). ConclusionThe difference in caries prevalence between the diabetic and non-diabetic children was not statistically significant. The CRT analysis revealed a higher frequency of “critical” pH values (pH = 4.5–5.5) and higher Lactobacillus counts in diabetic children than in non-diabetic children, which indicated a higher caries risk in the former group.

Changes in the oral environment after placement of removable dentures in low caries risk patients

Japan has a high distribution of aged citizens. Dental treatment significantly contributes to a high QOL in the elderly. Many people lose teeth because of caries and/or periodontal diseases. It is important to find the causes for this and to take preventive measures. In particular, systemic diseases in the elderly tend to worsen the oral environment, leading to an increased risk of caries. The caries activity test is useful in understanding the oral environment. A simple chairside test can measure the patient’s unstimulated and stimulated salivary flow rate, unstimulated and stimulated salivary buffering capacity, and salivary microbial counts, including mutans streptococci, lactobacilli and Candida. Information on these oral environment factors can aid in preventing caries based on individual risk, and extending the life of dental restorations. In Japan, missing teeth are usually replaced by fixed or removable prostheses. Using the saliva test, Narhi reported that salivary microbial counts were greater in elderly with dentures than in those with natural dentition. Our cross-sectional study, which used the same saliva test, reported that there were large differences in the number of cariogenic bacteria in the oral environment of elderly with fixed prostheses compared with those who had removable prostheses. Although these studies suggested that removable dentures may influence salivary microbial counts, it is still unknown whether they contribute to an increase in the counts. We did a follow-up study that examined the oral environment over time of low caries risk patients after initial placement of removable prostheses.

Effects of probiotic fermented milk on biofilms, oral microbiota, and enamel.

The aim of this study was to evaluate in vitro and in vivo the effects of 2 brands of probiotic fermented milk on biofilms, oral microbiota, and enamel. For the in situ experiment, ten volunteers wore palatine devices containing four blocks of bovine dental enamel over 3 phases, during which 20% sucrose solution, Yakult® (Treatment A), and Batavito® (Treatment B) were dropped on the enamel blocks. Salivary microbial counts were obtained and biofilm samples were analyzed after each phase. For the in vivo experiment, the same ten volunteers drunk Yakult® (Treatment C) and Batavito® (Treatment D) in two phases. Saliva samples were collected for microbial analysis after each phase. The in situ study showed that in comparison with Treatment A, Treatment B resulted in fewer total cultivable anaerobes and facultative microorganisms in biofilms, higher final microhardness, lower percentage change in surface hardness, and smaller integrated subsurface enamel hardness. In the in vivo study, Treatment D resulted in a reduction in the counts of all microorganisms. The results suggested that the probiotic fermented milk Batavito®, but not Yakult®, reduced the amount of oral microorganisms and mineral loss in bovine enamel.

Probiotic Lactobacillus paracasei effect on cariogenic bacterial flora

Lactobacillus paracasei has been demonstrated to inhibit the growth of many pathogenic microbes such as Streptococcus mutans, in vitro. However, its clinical application remains unclear. Here, we examined whether a novel probiotic L. paracasei GMNL-33 may reduce the caries-associated salivary microbial counts in healthy adults. Seventy-eight subjects (aged 20 to 26) had completed this double-blinded, randomized, placebo-controlled study. A probiotic/test (n = 42) and a control group (n = 36) took a L. paracasei GMNL-33 and a placebo oral tablet three times per day for 2 weeks, respectively. Bacterial counts of salivary S. mutans, lactobacilli, and salivary buffer capacity were measured with chair-side kits at the beginning (T1), the completion (T2) of medication, and 2 weeks after medication (T3). The results did not show differences in the counts of S. mutans and lactobacilli between probiotic and control groups at T1, T2, and T3. Nevertheless, within the probiotic group, an interesting probiotic effect was noticed. Between T1 and T2, no inhibitory effect against S. mutans was observed. However, a significant count reduction in the salivary S. mutans was detected between T2 and T3 (p = 0.016). Thus, a 2-week period of medication via oral administration route may be needed for L. paracasei GMNL-33 to be effective in the probiotic action.

Longitudinal research on the oral environment of elderly wearing fixed or removable prostheses

The purpose of this study was to investigate oral environmental risk factors involved in caries incidence in the elderly. We investigated the relationship between the oral environment factors of the elderly with both fixed prostheses and removable prostheses at baseline and at follow-up and examined time-course changes of each oral environmental factor by prosthesis type. The subject group consisted 11 elderly patients with fixed prostheses and 11 who wore removable prostheses. We examined oral environmental factors by saliva tests. Five oral environmental factors were examined: the stimulated salivary flow rate, buffering capacity, and the counts of mutans streptococci (SM), lactobacilli (LB), and Candida (CA). We compared these factors for subjects with fixed prostheses and those wearing removable prostheses at baseline and at follow-up. Furthermore, 3-year changes in the factors of each oral environment were compared and evaluated. Significant differences were observed between the two groups in the salivary microbial counts of SM and LB at baseline and at follow-up. The LB counts increased in the Denture group during the 3-year period and significant differences were noted. We found that fixed prostheses are less cariogenic, and removable prostheses cause an increase in the cariogenic bacterial count. Regarding time-course changes by the type of prosthesis, the LB count tended to increase in the subjects with removable prostheses. The risk of caries due to a fixed prosthesis may be lower than that of removable prostheses.

Salivary constituents and acidogenic microbial counts in coronary artery bypass graft patients from baseline to three-years after operation

Data on saliva in coronary artery bypass graft (CABG) surgery patients are sparse. Understanding salivary parameters, however, may aid clinical decision making. We hypothesized that cardiac surgery might affect patients' salivary flow rates and buffering, salivary proteins, and microbial counts. A 3-year, open follow-up study was conducted examining salivary flow, its chemical composition, and acidogenic microbial counts in 89 CABG surgery patients. The changes in salivary flow and proteins between baseline and 3-year post-CABG surgery were assessed using paired t-test and, with respect to the median of number of drugs used daily, by use of a nonparametric rank sum test. The results showed no long-term change in salivary flow rates and buffering capacity. With the exception of salivary urea, IgA and IgM concentration, and lysozyme output, the differences in salivary proteins between baseline and 3-year post-CABG were not statistically significant. No difference was observed in saliva values between patients taking drugs below or above the median number of drugs. Acidogenic microbial counts remained the same throughout the study. In conclusion, the salivary flow rates and constituents did not practically change in patients who underwent CABG surgery during the 3-year follow-up.

Enhancement of a Caries-resistant Oral Environment on Treatment Using Prosthesis

Patients: A 55-year-old woman with complaints of esthetic disturbance and masticatory dysfunction visited Osaka Dental University Hospital. The remaining upper teeth showed severe degradation of the coronal dentine because of caries. Additionally, the vertical stop in the molar region was lost. In the initial treatment, an overdenture was placed for urgent improvement of the chief complaint. We diagnosed the patient as having esthetic disturbance and masticatory dysfunction due to many decayed and missing teeth. Subsequently, we performed oral surgical, endodontic, and periodontal treatments of the remaining teeth based on the diagnosis. According to the patient’s request, fixed prostheses, i.e., crowns and fixed partial dentures, were selected as the final prostheses. On the other hand, since caries progression is possible during a long-lasting treatment, the patient’s oral environment has been monitored using a saliva test to estimate caries activity. We selected the following 4 factors as the oral environmental factors: the stimulated salivary flow rate, buffering capacity, and salivary microbial counts of mutans streptococci and lactobacilli. The first examination revealed a high-risk oral environment. However, lactobacilli counts decreased immediately after the cementing of fixed prostheses and were low-risk at recall. Other factors remained at low-risk-levels throughout the treatment period.Discussion: To improve esthetic disturbance and masticatory dysfunction, prosthetic treatment was performed, and the progressive degradation of tooth structures due to caries was prevented. The oral environment was examined by the saliva test during therapy. After the treatment, the lactobacilli counts decreased. This is thought to be the result of removing caries and poorly fitting restorations.Conclusion: By means of the saliva test, we confirmed the improvement in the oral environment following proper prosthetic treatment.

Short-term consumption of probiotic-containing cheese and its effect on dental caries risk factors

Cheese is known to contain compounds that reduce the risk of dental caries. The long-term consumption of milk containing Lactobacillus rhamnosus GG, ATCC 53103 (LGG), has been shown to reduce caries risk in children. The aim of the present study was to examine whether short-term consumption of cheese containing LGG and Lactobacillus rhamnosus LC 705 would diminish caries-associated salivary microbial counts in young adults. Altogether, 74 18–35 year-old subjects completed this double-blinded, randomised, placebo-controlled study. During the 3 week intervention, the subjects ate 5×15 g cheese per day. Oral examinations were made before and after the study. Stimulated salivary secretion rates, buffer capacity and counts of salivary Streptococcus mutans, yeast and lactobacilli were evaluated before and after the intervention and after a 3 week post-treatment period. The results showed no statistically significant difference between the groups in Streptococcus mutans counts after the intervention, but during the post-treatment period there was a significantly greater reduction in these counts in the intervention group compared to the control group ( P=0.05). However, Streptococcus mutans counts decreased in 20% ( P=0.01) and yeast counts in 27% ( P=0.005) of all the subjects, regardless of the intervention group. Results from logistic regression showed a trend indicating that probiotic intervention might reduce the risk of the highest level of Streptococcus mutans (OR=0.37, 95% CI 0.08–1.75, P=0.21) and salivary yeasts (OR=0.40, 0.09–1.71, P=0.22).

Salivary Findings, Daily Medication and Root Caries in the Old Elderly

Root caries is one of the main dental problems among the dentate old elderly. The aim of our study was to evaluate the occurrence of root caries in 196 dentate elderly (mean age 79.3) in relation to their salivary flow rate, buffering capacity and salivary microbial counts. These subjects participated in the oral health component of the Helsinki Aging Study in 1990–1991. Clinical oral examinations included assessment of the state of root surfaces and salivary flow rates, both paraffin-wax-stimulated and unstimulated. Salivary buffering capacity and the growth of salivary mutans streptococci, lactobacilli and yeasts were determined by means of commercially available kits. Root caries occurred in 52% of men and in 35% of women (p < 0.05). Number of decayed (DRS) and decayed or filled (DFRS) root surfaces correlated (r = 0.16 to 0.26) with salivary microbial counts. No correlation appeared between DRS and subjects’ salivary flow rates. Basic estimates on the association between DRS and salivary findings showed that microbial counts only produced significant odds ratios, from 2.0 to 3.5. However, in a log-linear model high salivary mutans streptococci and yeast counts together with male gender were associated with greater occurrence of root caries.

Five-year follow-up study of saliva, mutans streptococci, lactobacilli and yeast counts in lymphoma patients

Twenty-two patients out of the 79 that were originally included were examined 5 years after beginning anticancer therapy for lymphomas. The patients' cumulative data on salivary flow rate, buffering capacity and acidogenic microbial counts were compared with respective data of 17 patients who died during the follow-up. Stimulated saliva samples had been taken at baseline and during the cytostatic treatment with combination chemotherapy, and 1 year and 5 years later. Chair-side kits were used at the hospital ward for the assessment of the study parameters. Mean saliva flow at baseline was 1.5 +/- 0.7 ml/min in the surviving group and 1.5 +/- 0.8 ml/min in the deceased. Salivary flow rates were not affected by the anticancer treatment and there was no statistically significant difference between the groups in this respect. A significant difference was observed between the groups in salivary buffering capacity values at baseline: only 32% of the survived had low buffering capacity in comparison to 69% of those who later died (P < 0.02). Buffering capacity values remained low in 50% of the surviving patients 5 years later. Higher mutans streptococci and lactobacilli counts were seen among the deceased than in the survived patients but mutans streptococci decreased significantly in both groups after the start of the anticancer therapy (P < 0.05). The number of positive yeast counts increased consistently during the chemotherapy in both groups, being higher in the survived when compared with the deceased patients. Yeast counts remained positive 5 years later in 73% of the survived patients, while the mean mutans streptococci and lactobacilli counts decreased below baseline values. The results showed that persistently high salivary microbial counts and low buffering capacity may be linked with poor prognosis.

One‐year trial of the effect of rinsing with an amine fluoride‐stannous‐fluoride‐containing mouthwash on gingival index scores and salivary microbial counts in lymphoma patients receiving cytostatic drugs

This double-blind study was undertaken to evaluate the effect of twice-daily use of a mouthwash containing 0.025% of fluoride as amine fluoride-stannous fluoride (AmF + SnF) or 0.05% of fluoride as sodium fluoride (NaF) on visible plaque index (VPI) and gingival bleeding index (GBI) and on some salivary micro-organisms in patients suffering from non-Hodgkin or Hodgkin lymphomas. 79 patients were allocated at random to the two mouthwash groups. Mouthwashing began at the start of cancer chemotherapy. Results relating to 45 patients who completed a 1-year rinsing protocol showed a significant decrease in VPI and GBI in the AmF + SnF group. An increase was found in the NaF group. Mean values for stimulated salivary secretion rates and buffering capacities mostly did not differ significantly from baseline values during the study. In both groups, mutans streptococci counts decreased significantly after the study began and remained low in the AmF + SnF group. No corresponding effect was seen in relation to lactobacilli and yeast counts. In the NaF group, lactobacilli counts increased significantly over a year. Significantly more patients reported adverse or unpleasant effects in the AmF + SnF group (52%) than in the NaF group (6%), although both solutions had the same colour and taste. However, all patients continued with rinsing.

Effect of an Experimental Antiplaque Preparation on Salivary Microbial Counts in Military Academy Cadets Refraining from Mechanical Cleaning of the Teeth

Dental emergencies in the army are mostly due to infections of the teeth, caused by dental plaque micro-organisms. Because practicing normal oral hygiene is restricted during terrain maneuvers, for example, we developed a new antiseptic tablet preparation which can be used to make an antiplaque solution or even chewed and thus mixed with saliva to rinse the mouth. The preparation contains chlorhexidine, fluoride, and xylitol (XYLIHEX) and can be added to the soldier's kit. The efficiency of the preparation on selected oral micro-organisms was tested against mouthwash solutions containing plain chlorhexidine (CHX) and sodium fluoride (F) in 45 military cadets who volunteered to participate in this double-blind cross-over study. The results showed a significant decrease in salivary mutants streptococci after rinsing periods with XYLIHEX and CHX when compared with F (p less than 0.001). Lactobacilli and yeast counts were not affected. The new preparation appeared promising as a new means for improving soldiers' oral hygiene.

Effect of antiseptic mouthwashes on some clinical and microbiological findings in the mouths of lymphoma patients receiving cytostatic drugs

51 patients suffering from Hodgkin's disease or non-Hodgkin's lymphoma participated in this double-blind, cross-over study in which 2 antiseptic mouthwashes were tested for their effects on various periodontal index scores and salivary microbial counts. All patients were receiving combination cytostatic treatment based on methotrexate and doxorubicin. The patients (49 +/- 14 years old, 28 men, 23 women) were allotted at random to 2 groups. One rinsed with a 0.12% chlorhexidine gluconate (CHX) solution, the other with a 0.025% amine-stannous fluoride (AmF + SnF) solution 2x daily for 2 weeks. Both groups then continued rinsing with a 0.05% sodium fluoride (F) solution for 2 weeks, before switching over to AmF + SnF or CHX, respectively. All solutions had been prepared in such a way that they had the same colour and taste. Visible plaque index and gingival bleeding index scores were significantly reduced after periods of rinsing with CHX solution (P less than 0.001) and AmF + SnF solution (P less than 0.05). Microbiological cultivations of saliva specimens revealed significant reductions in mutans streptococci immediately after commencing rinsing, while lactobacilli and yeast counts were not affected.

Effect of Extraction of Partly Erupted Third Molars on Salivary Microbial Counts in Conscripts

Viable counts of mutans streptococci, lactobacilli and yeasts in saliva were followed for 5 months after extraction of partly erupted third molars in 49 conscripts aged 19.9 +/- 0.8 years. For controls, 27 conscripts aged 19.7 +/- 1.2 years were studied who did not have indications for third molar extractions. The microbiological analyses were made from paraffin-wax-stimulated saliva using dip-slide techniques. The results showed a statistically significant reduction of the high counts of mutans streptococci (greater than or equal to 10(6) CFU/ml saliva) and lactobacilli (greater than or equal to 10(5) CFU/ml saliva), both 2 and 5 months after extraction, when compared with the baseline values and with the controls. The extraction of partly erupted third molars did not appear to affect salivary yeast counts. We suggest that partly erupted wisdom teeth act as reservoirs for mutans streptococci and lactobacilli, in particular, and that their state of eruption must be taken into account when interpreting salivary microbiological counts.

Analytical and physiological variability of salivary microbial counts.

Quantitation of mutans streptococci (MS) and Lactobacillus has been proposed as a method for the identification of patients at high risk for dental caries. The purpose of the present study was to investigate the analytical and physiological variability of this procedure. Variability due to specimen collection and processing was investigated by repeated sampling studies. Sample stability was investigated over storage periods of up to 72 hr at 5 degrees C, room temperature, and 37 degrees C. Physiological variability was investigated by performance of serial analyses on ten individuals, who collected six samples at intervals on a single day, and rising and noon samples on ten subsequent days. Sample collection, rather than sample processing, was found to be the major factor determining the imprecision of salivary microbial analysis in the majority of cases. However, individual subjects varied considerably in the consistency with which they provided saliva samples. Imprecision due to sample processing was relatively small, with coefficients of variations of 2.3% for MS counts and 2.1% for Lactobacillus counts. Samples were generally stable over a wide temperature range for at least 72 hours, although there was some loss of viability of lactobacilli on prolonged storage at room temperature or 37 degrees C in one experiment. Rising samples yielded higher counts than samples collected after breakfast and toothbrushing. Day-to-day variability was considerable, with 95% confidence limits exceeding 1 log in 28% of data sets for MS count and 39% of data sets for Lactobacillus.

Erupting third molars and salivary lactobacilli and Streptococcus mutans counts.

The salivary lactobacilli and Streptococcus mutans counts in 217 university students of 25.4-yr-old were studied with regard to the state of eruption of their third molar teeth. Statistically significantly higher counts of both bacterial species were found in students who had one or more third molars partly erupted, compared with those whose third molars were lacking or fully erupted. No other parameters studied such as salivary flow rate or buffering capacity of the saliva were found to explain the high bacterial counts. These findings should be taken into consideration when interpreting salivary microbial counts in young adults. Also, special interest should be focused into these aspects at oral hygiene and dietary counseling of young patients.