Multilocus sequence typing and phenotypic properties of Streptococcus mutans from Thai children with different caries statuses.

BACKGROUND: Streptococcus mutans is studied for its acidogenic and aciduric characteristics, notably its biofilm formation in the presence of sucrose, toward its role in the caries process. Variations in both genotype and phenotype have been reported among clinical isolates of S. mutans. This study aimed to examine genotypic and phenotypic characteristics of S. mutans obtained from Thai children with varying caries statuses. METHODS: We determined the presence of S. mutans and caries status in 395 children aged 3-4 years. From 325 children carrying S. mutans, we selected 90 with different caries statuses-caries-free (CF; n = 30), low severity of caries (LC; n = 30), or high severity of caries (HC; n = 30). Three isolates of S. mutans were taken from each child, thus, a total of 270 isolates were obtained. Multilocus sequence typing (MLST) was used to genotype the isolates and assess their clonal relationships. The properties, including biofilm formation, collagen binding, and acid production and tolerance were also evaluated. RESULTS: Children with carious lesions showed a higher detection rate and number of S. mutans in saliva than those without caries. S. mutans from individuals with HC status showed the lowest biofilm formation ability, while this group had the highest detection rate of collagen-binding isolates. There was no difference in acid production or tolerance by caries status. Genotyping by MLST did not reveal any clone of S. mutans specific to CF status. This result remained even when we included MLST data from the open-access PubMLST database. MLST did identify clones containing only strains from caries-affected hosts, but tests of their phenotypic properties did not reveal any differences between S. mutans from these clones and clones that were from both caries-free and caries-affected children. CONCLUSIONS: The clonal relationships of S. mutans indicated by MLST were not associated with the status of dental caries in the host.

The formation of cariogenic plaque to contemporary adhesive restorative materials: an in vitro study.

The research exploiting the ability of dental materials to induce or prevent secondary caries (SC) development still seems inconclusive. Controlling bacterial adhesion by releasing bacteriostatic ions and improving the surface structure has been suggested to reduce the occurrence of SC. This paper analyses the impact of five distinctively composed dental materials on cariogenic biofilm formation. Forty-five specimens of three composites (CeramX Spectra ST, Admira Fusion, Beautifil II) and two glass-ionomers (Fuji II LC, Caredyne Restore), respectively, were incubated in bacterial suspension composed of Streptococcus mutans, Lactobacillus acidophilus, Streptococcus mitis, Streptococcus sanguinis, and Streptococcus salivarius at pH 7.0 and 5.5. Coverslips were used as a control. Adhered bacteria were collected after 2, 4, 6, 12, 24, and 48 h and analyzed using quantitative polymerase chain reaction (qPCR). Fluoride leakage was measured at each collection. The specimens' surface topography was assessed using interferometry. In the present study, surface roughness seemed to have a partial role in bacterial adhesion and biofilm formation, together with chemical composition of the materials tested. Despite differences in fluoride leakage, biofilm accumulation was similar across materials, but the number of adhered bacteria differed significantly. A release of other ions may also affect adhesion. These variations suggest that certain materials may be more prone to initiating secondary caries.

Antimicrobial efficacy of chlorine agents against selected oral pathogens.

OBJECTIVES: Method-dependent comparison of antimicrobial agents' efficacy against oral pathogens. MATERIALS AND METHODS: Several sodium hypochlorite solutions (NaOCl)-Perisolv®, Carisolv® and Dakin's solution-were equated with chlorhexidine (CHX) and hydrogen peroxide (H2O2) against ten oral micro-organisms related to caries and periodontitis using different minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) techniques. Agents were adjusted to the final 70 mmol/L concentration of active chlorine molecule. RESULTS: Apart from H2O2 and the amino acids of Perisolv®, all the agents revealed an antimicrobial effect. Agar diffusion test ranked CHX (p < 0.05) as the most effective against all ten specimens, followed by the NaOCl of Perisolv® and Dakin's solution. Correspondingly, in broth microdilution on agar, CHX was the most effective in eradicating micro-organisms at 0.03 mmol/L compared with 2.2 mmol/L of Dakin's solution. In contrast, the bactericidal concentration of Dakin's solution was the most effective at 0.2 mmol/L, (p < 0.001), followed by Perisolv® (2.14 mmol/L), CHX (2.38 mmol/L) and Carisolv® (3.33 mmol/L) after 5 and 10 min in broth dilution test. In live/dead analysis, 60-min exposure to a 2-fold concentration of agents resulted in two-log Aggregatibacter actinomycetemcomitans inhibition by CHX (35 mmol/L) whilst Streptococcus mutans was more susceptible, in 0.8 and 8.8 mmol/L, after 10 min to CHX and Dakin's respectively. CONCLUSION: Replacement of CHX with tested hypochlorite agents showed evident potential and promoted rapid antimicrobial effect. CLINICAL RELEVANCE: Effective antimicrobial agents are crucial in controlling pathogen-induced oral infections increasing clinical possibilities to combat oral biofilms. Additionally, CHX substitution with hypochlorite agents could eliminate CHX's adverse effects.

The effect of a non-tobacco-based nicotine pouch on mucosal lesions caused by Swedish smokeless tobacco (snus).

Oral mucosal lesions are commonly found in Swedish smokeless tobacco (snus) users where the pouch is placed. These lesions are reversible, that is, clinical and histological tissue changes return to normal following cessation. However, the exact mechanisms behind these changes are unknown. The main aim of this study was to investigate how snus-like non-tobacco-based nicotine pouches affect the oral mucosa and the severity of pre-existing lesions. Sixty regular users of Swedish smokeless tobacco were encouraged to substitute their snus with non-tobacco-based nicotine pouch products during a 6-week period. Meanwhile, oral mucosal lesions were assessed using a four-degree scale. Over time, a reduction of pre-existing mucosal lesions was observed between baseline and the final visit. In a second part, the effect of exposure to regular snus on the production of 48 different cytokines in peripheral blood mononuclear cells was compared in vitro with that resulting from exposure to the non-tobacco-based nicotine products. Results showed significantly increased production of proinflammatory cytokines in cells exposed to regular snus compared to untreated or cells exposed to the non-tobacco-based nicotine products. This may be related to the improved clinical appearance of the oral mucosa in the participants that used the non-tobacco-based nicotine test pouches.

Effect of drops containing Lactobacillus reuteri (DSM 17938 and ATCC PTA 5289) on plaque acidogenicity and other caries-related variables in orthodontic patients.

BACKGROUND: The purpose of the study was to investigate the effect of probiotics on biofilm acidogenicity and on the number of salivary Streptococcus mutans and lactobacilli in orthodontic patients. METHODS: This RCT was conducted on 28 young adults who were undergoing orthodontic treatment. The short-term prospective clinical trial lasted for three weeks. The test group rinsed daily with drops containing two Lactobacillus reuteri strains diluted in water, while the placebo group used drops without probiotics. The subjects were enrolled eight months since the beginning of orthodontic treatment. Plaque-pH, saliva and dental biofilm samples were obtained at baseline, one week and three weeks post intervention. RESULTS: Twenty-seven subjects successfully completed the trial period, only one drop out in the test group. No side effects were reported. A statistically significant increase in plaque pH at three weeks post-intervention was found for the test group (p < 0.05), while insignificant changes in the pH value were found for the placebo group in comparison to baseline (p > 0.05). In addition, the AUC7.0 showed a significant difference at three weeks between the test and placebo (p = 0.00002). The three-week samples of stimulated whole saliva showed a statistically insignificant difference in the number of S. mutans and lactobacilli between the two groups (p > 0.05). The qPCR analysis showed the ability of the two strains to get colonized in the dental biofilm without a significant effect on the microbial counts. CONCLUSION/CLINICAL IMPLICATIONS: A mixture of Lactobacillus reuteri has the ability to reduce the pH fall at the three-week follow-up. However, the short-term use of probiotics does not appear to have an effect on the number of salivary Streptococcus mutans and lactobacilli in saliva and on the dental biofilm. TRIAL REGISTRATION: Clinicaltrial.gov (Identifier: NCT04593017 / (19/10/2020)).

Oral health profile of postbariatric surgery individuals: A case series.

OBJECTIVES: To describe the oral health profile of individuals who had undergone gastric bypass surgery (GBP) or sleeve gastrectomy (SG) to generate hypotheses for further studies. MATERIAL AND METHODS: Fourteen individuals treated with GBP or SG surgery ≥ 2 years ago and with observed and/or perceived oral problems were recruited to a case series. The documentation included clinical and radiographic examinations, biomedical sampling, and self-reported diet and questionnaires. The results are presented descriptively. RESULTS: The age range was 31 to 66 years and all had a BMI > 25 (range 25.4-44.7). Only four participants were fully dentate. Eleven out of 14 individuals exhibited severe decay. A majority had poor oral hygiene and high bacterial counts. The flow rates of unstimulated saliva were extremely low and hyposalivation was present in ten of the fourteen cases. Most perceived several oral health problems, such as chewing difficulty and tooth hypersensitivity. CONCLUSIONS: Individuals who had undergone GBP or SG surgery had poor clinically diagnosed oral health and perceived oral health problems. Longitudinal studies are needed to monitor the patients' oral health, from before bariatric surgery to long-term postoperatively.

Opportunities for caries prevention using an ion-releasing coating material: a randomised clinical study.

Ion-releasing materials (containing fluoride and boron, for example) have shown caries-preventive effects in vitro. The purpose of the present study was to investigate the impact of multi-ion-releasing coating material on pH stabilisation, plaque accumulation and the bacterial composition of dental plaque during a time period of 90 days. The null hypothesis tested here was that the evaluated material would not show any differences in pH stabilisation, plaque accumulation or bacterial composition compared with control material.The study was carried out as a double-blind, split-mouth, randomised, controlled clinical trial in 28 volunteers. Over the evaluation period (days 4, 30, 60 and 90), pH measurements, plaque index and plaque sampling for bacterial analyses were conducted in a calibrated, standardized manner. The study received ethical permission and was carried out in accordance with the Helsinki Declaration.A significant difference was observed, with less plaque accumulation over time in the subjects in whom the ion-releasing material was applied in comparison to the non-active group. No significant difference was evident in terms of either pH stabilisation or plaque levels of mutans streptococci.The null hypothesis relating to plaque accumulation was rejected, with a lower plaque index shown for the test group up to 60-90 days. No adverse effects during the observation period were observed. Since the studied cohort was healthy from a caries perspective, more clinical studies are needed to further evaluate the caries-prevention potential of the ion-releasing material in other patient groups.

Oral Colonisation after the Administration of Drops Containing Lactobacillus reuteri.

PURPOSE: To investigate the oral colonisation potential after four weeks' administration of Lactobacillus reuteri and to examine the short-term effect of probiotics on salivary Streptococcus mutans and lactobacilli. MATERIALS AND METHODS: The study group comprised 13 young adults who volunteered after receiving verbal and written information. The short-term prospective clinical trial lasted 9 weeks, consisting of a 4-week intervention period with administration twice daily and a 5-week post-administration follow-up period with no probiotic consumption. Saliva and dental biofilm samples were obtained immediately before probiotic administration, after 2 weeks and after 4 weeks of L. reuteri administration. Follow-up samples were collected once every week on a regular basis after administration was terminated. The numbers of salivary S. mutans and lactobacilli were assessed by regular plating, while the presence of the two L. reuteri strains in saliva and dental biofilm was evaluated using quantitative polymerase chain reaction (qPCR). RESULTS: The occurrence of L. reuteri in the oral cavity increased gradually during the intervention period and reached the maximum level after four weeks of probiotic administration (p < 0.0001). The 4-week samples of stimulated whole saliva showed a statistically significant decrease in the number of S. mutans and a statistically significant increase in the salivary lactobacilli level in comparison to baseline. qPCR showed that the DSM 17938 strain has better colonisation for both saliva and dental biofilm than the ATCC PTA 5289 strain at the nine-week follow-up. CONCLUSION: Probiotics have the ability to colonise the oral cavity during usage, but it gradually disappears after the completion of intake. It also has ability to decrease the number of salivary S. mutans.

Effect of Different Toothbrushing Routines on Interproximal Fluoride Concentration.

This study aimed to evaluate the effect of different toothbrushing routines and different kinds of toothpaste on the interproximal fluoride concentration after toothbrushing and its clinical relevance to the recommendations given to patients regarding the process of toothbrushing. Eight adults participated a total of 8 times in order to test different toothbrushing routines with different amounts of toothpaste (1 or 2 cm), durations (1 or 2 min) and amounts of water after toothbrushing (10 or 20 mL). An additional 8 adults participated 6 times in total to test different forms of toothpaste administration (paste, gel and foam) with different amounts of water after toothbrushing (no rinsing or 10 mL). Interdental saliva samples were collected from proximal sites 25/26 and 46/45 using small paper points, before and up to 60 min after toothbrushing. The fluoride concentration was measured by an ion-specific electrode. The area under the curve, saliva fluoride concentration versus time, was calculated. Differences between the groups were tested by ANOVA with Tukey's multiple comparisons test. An increase in fluoride concentration of 47.2% was observed when the amount of toothpaste increased from 1 to 2 cm (p < 0.01), 26.8% when increasing the duration from 1 to 2 min (p < 0.01) and 41.2% when reducing the amount of water rinsing from 20 to 10 mL (p < 0.01). The paste and gel resulted in higher fluoride concentration (p < 0.01) compared with foam. These findings suggest that the amount of toothpaste, the duration and the amount of water have a significant effect on fluoride concentration after toothbrushing. Furthermore, despite the lower amount of fluoride, the gel gives almost the same fluoride concentration after toothbrushing as the toothpaste. The results confirm the importance of giving clear advice to patients regarding the process of toothbrushing.