Outreach dental care programme for older adults using long-term care services in Hong Kong: A qualitative study.

OBJECTIVES: To explore the effects and improvement needs of an outreach dental care programme (ODCP) for older adults using residential care or daycare services from the perspectives of the caregivers, the dentists and administrative staff involved in the implementation of the ODCP. METHODS: A qualitative study was conducted through semi-structured interviews with three stakeholders, long-term care (LTC) facility caregivers, administrative staff and dentists working for the ODCP. Combined maximum variation and snowball sampling strategies were adopted, and 22, 9 and 7 participants were interviewed from each stakeholder, respectively. The interviews were conducted via telephone, which were audio-recorded and transcribed verbatim for analysis. NVivo software was used for storing and analysing the data. Data analysis was conducted continuously during the study. RESULTS: Most participants opined that the ODCP benefited older adults by raising their oral health conditions and awareness. However, they complained of the complicated administrative procedures, unmet dental treatment needs, inefficient coordination, unclear work guidelines and shortage of dental manpower. More advanced dental treatment options, better coordination among different parties, simpler administrative processes and better incentives for dentists were proposed to further improve the programme. CONCLUSIONS: According to the stakeholders, ODCP seems beneficial to older adults using LTC services. Further improvements in the scope of dental treatments, cooperation between the outreach dental teams and caregivers, and streamlining of the administrative process are needed for the provision of effective outreach dental care to satisfy the unmet treatment needs of older adults who use LTC services. Better incentives are needed to attract and retain dentists.

Silver Compounds for Caries Management.

Silver metal and compounds have antibacterial properties, although their action's mechanisms are not fully understood. Scientists generally consider that silver disrupts the bacterial cell wall. It causes a structural change in the bacterial cell membrane and cytoplasm. It also stops deoxyribonucleic acid replication, resulting in inactivating enzymatic activity and cell death. The antimicrobial effect of silver-containing compounds relies on the release of bioactive silver ions. Hence, silver metal and compounds have been used in medicine to prevent infection for hundreds of years. Silver metal and compounds are also used as antibacterial agents in dentistry. Studies have shown that silver compounds are effective in the management of dental caries. Fluoride-containing silver compounds have been found in experiments to be beneficial at remineralising dental cavities. Silver diamine fluoride (SDF) can assist in preventing and arresting tooth cavities. The World Health Organization included SDF in its Model List of Essential Medicine for both adults and children in 2021. Clinicians also use SDF to manage dentine hypersensitivity as well as to inhibit growth of periodontal pathogens. However, traditional silver compounds cause tooth discolouration because of the silver-staining effect. These side effects of their applications depend on the amount applied and the frequency of application. Researchers are developing nanosilver fluoride and silver nanoparticles to overcome the staining. This review gives an overview of the antibacterial mechanism of silver compounds, namely silver nitrate, silver fluoride, SDF, silver nanoparticles, and nano silver fluoride for caries management. The outlook for the future development of silver compounds will be discussed.

Effect of fluoride varnishes on oral bacteria of preschool children with cavitated and non-cavitated carious lesions: randomized clinical trial.

We compare the effect of calcium and phosphate-containing sodium fluoride (NaF) varnishes to conventional NaF varnish on S. mutans and L. fermentum counts. 3-4 years old children were grouped according to their caries status (n = 45 each): caries-free, with non-cavitated and with cavitated lesions. Each group was randomly subdivided (n = 15 each) into: Group 1- 5% NaF, Group 2- 5% NaF with tricalcium phosphate, Group 3- 5% NaF with casein phosphopeptide- amorphous calcium phosphate. Biofilm and saliva were collected to quantify microorganisms at baseline (T1) and 24-months (T2). Differences between groups were compared using Kruskal-Wallis test, followed by Dunn-Bonferroni post-test, at 0.0167 α-level. Significant difference was found for percentage of children with detectable biofilm L. fermentum (p = 0.013) at T1 and salivary S. mutans (p = 0.011) at T2. Percentage of children increased from T1 to T2 in Group 2 with salivary S. mutans (p = 0.007), salivary L. fermentum (p = 0.035), and biofilm L. fermentum (p = 0.019) and in Group 3 with salivary L. fermentum (p = 0.035). Bacterial change was not significant in both samples of intervention groups, except increase in salivary S. mutans (p = 0.038) in Group 3. Both calcium- and phosphate-containing NaF varnishes demonstrated similar antibacterial effect on S. mutans and L. fermentum compared to conventional NaF varnish.

Is Mutans Streptococci count a risk predictor of Early Childhood Caries? A systematic review and meta-analysis.

BACKGROUND: The review aims to determine the risk predictability of mutans streptococci in the development of carious lesions in children with primary dentition. METHODS: Longitudinal observational studies with at least 6 months follow-up and evaluating mutans streptococci presence in caries-free children under 6 years of age for the development of any cavitated or non-cavitated carious lesion. Six databases and grey literature were searched without any restrictions. Risk of bias was evaluated using the New Castle Ottawa scale for longitudinal studies, and the certainty of the evidence was evaluated by Grading of Recommendations Assessment, Development and Evaluation using GRADEpro software. Meta-analysis was performed using a random effect (DerSimonian and Laird, DL) model, and heterogeneity was evaluated using tau-squared, I2 statistics and prediction interval. Sensitivity analysis was performed to assess the relationship between the mutans streptococci presence at baseline and the caries development, according to the sample and methods used for the microbiological assessment and the length of follow-up of the studies. Publication bias was checked by funnel plot using a random effect (DerSimonian and Laird, DL) model. RESULTS: Twelve studies met the inclusion criteria and were included in the review. Four studies received a maximum of 9 stars, and among the remaining eight studies, six received 8 stars and the rest two studies were assigned 7 stars in the risk of bias scale. After pooling the results quantitatively, odds ratio (OR) was found to be 4.13 (95% CI: 3.33, 5.12), suggesting that children with mutans streptococci had 4 times higher odds of developing caries later (p < 0.001). Four studies were pooled to compare future caries experience among children with and without mutans streptococci at baseline, obtaining standardized mean difference (SMD) of 0.85 (95% CI: 0.33, 1.37), indicating a large effect (p < 0.001). Certainty of evidence was found to be moderate, and no publication bias was reported by the funnel plot criteria of symmetry. CONCLUSIONS: Presence of mutans streptococci in a preschool child is a risk predictor for future caries experience. Early identification of children with increased caries-risk may facilitate in implementation of appropriate preventive strategies.

A Personalised 3D-Printed Dental Plaque Removal Mouthguard for Older Adults.

OBJECTIVES: The aim of the present study was to examine the plaque removal effectiveness of a personalised 3D-printed dental plaque removal mouthguard device in a clinical trial setting. METHODS: A personalised 3D-printed mouthguard was developed to clean dental plaque using micro-mist. A clinical trial was conducted to examine the plaque removal effectiveness of this device. The clinical trial recruited 55 participants (21 males and 34 females) with an average age of 68.4 years (range, 60-81 years). Dental plaque was dyed by plaque disclosing liquid (Ci). Turesky Modification of the Quigley-Hein Plaque Index (TMQHPI) was used to evaluate the level and rate of plaque formation on the tooth surface. The TMQHPI was recorded and intraoral photos were taken before and after mouthguard cleaning. The plaque removal rate was calculated based on TMQHPI and intraoral photos (pixel-based method) before and after cleaning. RESULTS: The personalised 3D-printed micro-mist injection mouthguard can be effective in dental plaque removal on tooth and gingiva, and the effectiveness lies between that of a manual toothbrush and a mouth rinse. The newly proposed pixel-based method can be a practical, high sensitive tool to evaluate the level of plaque formation. CONCLUSIONS: Under the conditions of the present study, we conclude that the personalised 3D-printed micro-mist injection mouthguard can be useful in reducing dental plaque and may be especially suitable for older adults and disabled people.

Quantitative analysis of salivary and biofilm bacteria associated with cavitated and non-cavitated carious lesions in pre-school children.

OBJECTIVE: To quantify and compare Streptococcus mutans (S. mutans) and Lactobacillus fermentum (L. fermentum) in saliva and biofilm of caries-free children to those with cavitated and non-cavitated lesions. DESIGN: One hundred and thirty-five 3-4 years old children were grouped (n = 45 in each group) according to their caries status: Clinical examination was done by a calibrated examiner. Biofilm and saliva were collected to quantify the microorganisms using qRT-PCR. The decayed-missing-filled surfaces (dmfs) was calculated by adding the number of decayed (ICDAS-II score 3-6), filled (ICDAS-II score 7 and 8) and missing (ICDAS-II score 9) surfaces due to caries. The correlation between the bacterial amounts and the number of carious surfaces was evaluated using Spearman's correlation coefficient. The levels and proportions of the microorganisms were compared using the Kruskal-Wallis test at an α-level of 0.05. RESULTS: The quantity of S. mutans and L. fermentum was significantly higher in saliva and biofilm of children with cavitated lesions, followed by those with non-cavitated lesions and the lowest in caries-free children. Also, salivary and biofilm S. mutans, along with biofilm L. fermentum levels, significantly correlated with the number of non-cavitated surfaces; while salivary and biofilm S. mutans and L. fermentum levels significantly correlated with the number of cavitated surfaces. Additionally, dmfs scores significantly correlated with the salivary and biofilm S. mutans and L. fermentum levels. CONCLUSIONS: S. mutans and L. fermentum in saliva and biofilm samples are associated with caries lesion severity.

Outreach dental care program for older adults using residential care or day care services in Hong Kong: A cohort study.

AIM: To evaluate the effects of an outreach dental care program (ODCP) on the oral health status and oral health-related quality of life (OHRQoL) of older adults who used residential or day care services in Hong Kong. METHODS: Older adults who had received dental treatments provided in the ODCP were recruited. Clinical examinations were performed by one calibrated examiner (SXY) at baseline and 1-year follow-up in the residential homes or day care centres. Face-to-face interviews were conducted using the transition scale of the Oral Health Impacts on Daily Living (OHIDL) questionnaire to investigate the perceived change in OHRQoL at baseline, 2-month and 1-year follow-ups. The Wilcoxon matched-pair signed-rank test or McNemar/McNemar-Bowker test was used to explore the change in oral health status after dental treatments. Factors associated with the perceived change in OHRQoL were explored with binary logistic regression. RESULTS: Four hundred and thirteen older adults (mean age = 83.8 years) participated in the study at baseline, and 377 (91.3%) and 359 (86.9%) were successfully followed 2 months and 1 year after receiving the outreach dental service, respectively. At the 1-year follow-up, the number of decayed teeth and functional tooth units, and the prevalence of poor denture hygiene decreased while there was more dental plaque deposition and a higher proportion of participants with gingival bleeding upon probing. More than 50% of the participants perceived no change or an improvement in OHRQoL in all domains at both follow-ups. Older adults who perceived their oral health status as 'healthy or fair' and those who suffered from toothache at baseline had a higher chance to perceive having a better or at least the same OHRQoL at the 2-month and 1-year follow-ups, respectively. CONCLUSIONS: The ODCP in Hong Kong can solve some of the dental problems of older adults using long-term care services and keep most of them from deterioration in OHRQoL, especially those suffering from toothache.

RISK PREDICTORS OF EARLY CHILDHOOD CARIES INCREMENT-A SYSTEMATIC REVIEW AND META-ANALYSIS.

This systematic review aimed to investigate the risk predictors of caries in primary teeth and evaluate their association with the increment of Early Childhood Caries (ECC) among preschool children. This systematic review included only cohort or case-control studies of at least 2 years duration, over 300 participants and with English full-text. Potentially eligible studies were retrieved from 4 electronic databases (Ovid Embase, Ovid MEDLINE; PubMed, Web of Science) from inception to March 1, 2021. Independent screening and data extraction by 2 reviewers to identify factors associated with ECC increment, including family and socioeconomic factors, dietary and oral health-related habits, and clinical parameters. A total of 18 studies from 163 potential reports were included, involving 1,159,226 preschool children. Lower parental education attainment was found associated with ECC increment (WMD:0.87; 95% CI 0.52, 1.21); whereas immigration status (WMD:-0.38; 95% CI -1.09, 0.34), gender (WMD:-0.02; 95% CI -0.28, 0.24), and dental service utilization (WMD:0.35; 95% CI -0.10, 0.79) were not significant factors for ECC increment. All included studies consistently suggested positive correlations between ECC increment and baseline caries experience, plaque level, cariogenic microorganisms, and prenatal and passive smoking, while mixed findings were detected between ECC increment with dietary and oral hygiene practices. Preschool children whose parents have low education level are more likely to have greater increment of ECC over 2 years. Existing caries lesions, increased dental plaque level, cariogenic microorganisms, prenatal or passive smoking were also consistently identified as risk factors for ECC in all reviewed studies. This systematic review highlights specific risk factors to target for the prevention of ECC and supports implementing more oral health promotion for preschool children with parents of lower educational attainment.

Compare the physicochemical and biological properties of engineered polymer-functionalized silver nanoparticles against Porphyromonas gingivalis.

Background: Some polymer-functionalized AgNPs (P-AgNPs) have been developed to optimize the biological properties of AgNPs. However, there are no studies in the literature comparing the differences in physicochemical and biological properties of AgNPs caused by various polymer-functionalizations and providing evidence for the selection of polymers to optimize AgNPs. Methods: Two AgNPs with similar nano-size and opposite surface charges were synthesized and functionalized by seven polymers. Their physicochemical properties were evaluated by UV-Visible absorption, dynamic light scattering, transmission electron microscopy and inductively coupled plasma optical emission spectroscopy. Their biological properties against Porphyromonas gingivalis and human gingival fibroblast were investigated by MIC determination, time-dependent antibacterial assay, antibiofilm activity and cell viability assay. Silver diamine fluoride, AgNO3 and metronidazole were used as positive controls. Results: Comparative analysis found that there were no significant differences between P-AgNPs and AgNPs in nano-size and in surface charge. Raman spectroscopy analysis provided evidence about the attachment of polymers on AgNPs. For antibacterial property, among the negatively charged AgNPs, only polyvinylpyrrolidone (PVP)-functionalized AgNPs-1 showed a significant lower MIC value than AgNPs-1 (0.79 vs. 4.72 µg/ml). Among the positively charged AgNPs, the MIC values of all P-AgNPs (0.34-4.37 µg/ml) were lower than that of AgNPs-2 (13.89 µg/ml), especially PVP- and Pluronic127-AgNPs-2 (1.75 and 0.34 µg/ml). For antibiofilm property, PVP-AgNPs-1 (7.86 µg/ml, P = 0.002) and all P-AgNPs-2 (3.42-31.14 µg/ml, P < 0.001) showed great antibiofilm effect against P. gingivalis biofilm at 5* to 10*MIC level. For cytotoxicity, all negatively charged AgNPs and PVP-AgNPs-2 showed no cytotoxicity at MIC level, but significant cytotoxicity was detected at 2.5* to 10*MIC levels. Conclusion: Among the polymers studied, polymer functionalization does not significantly alter the physical properties of AgNPs, but modifies their surface chemical property. These modifications, especially the functionalization of PVP, contribute to optimize the antibacterial and antibiofilm properties of AgNPs, while not causing cytotoxicity at the MIC level.

Motivational interviewing for caries prevention in adolescents: a randomized controlled trial.

OBJECTIVE: The objective of this study is to investigate the effectiveness of motivational interviewing (MI) in changing health behaviors (snack and toothbrushing) and preventing dental caries among adolescents. METHODS: Five hundred and twelve adolescents with unfavorable caries-related behaviors ("snacking three times or more a day" and/or "toothbrushing less often than twice a day") were randomly assigned to three groups. Group I received prevailing health education (oral health talks and pamphlets). Participants in group II joined a one-on-one face-to-face MI session. In group III, a patient communication tool (Cariogram) was incorporated to facilitate the MI process. At baseline and 24 months post-intervention, a self-administered questionnaire gathered information of participants' sociodemographic characteristics and oral health self-efficacy and behaviors. Their oral hygiene and tooth status were assessed by a blinded examiner. RESULTS: After 24 months, 460 (89.8%) participants were followed up. Compared with group I, (i) restriction of frequent snacking was more likely in group II [OR (95% CI): 3.91 (1.48-10.33)] and group III [OR (95% CI): 6.33 (2.46-16.27)], whereas group III tended to adopt the behavior of toothbrushing twice a day [OR (95% CI): 4.80 (1.79-12.85)]; (ii) no significant between-group difference in plaque score reduction was found (p > 0.05); and (iii) groups II and III developed fewer cavitated teeth (△DICDASII 3-6MFT) [ß (95% CI): - 0.19 (- 0.37, - 0.01) and - 0.20 (- 0.38, - 0.02), respectively], whereas increment of total carious lesions (△DICDASII 1-6MFT) was lower in group III [ß (95% CI): - 0.63 (- 1.24, - 0.02)]. CONCLUSION: MI outperformed prevailing health education in improving oral health behaviors and preventing dental caries among adolescents. CLINICAL RELEVANCE: Incorporating MI into dental care for caries-prone adolescents contributes to optimal health outcomes. TRIAL REGISTRATION: HKUCTR-1852 ( http://www.hkuctr.com/ ) (Hong Kong, 2013).

Horizontal Transmission of Streptococcus mutans in Children and its Association with Dental Caries: A Systematic Review and Meta-Analysis.

Purpose: To systematically evaluate the horizontal transmission of Streptococcus mutans in children and analyze its relationship with dental caries. Methods: Seven databases were searched for observational studies that have determined the transmission of S. mutans among children younger than seven years. Selection of included studies, data extraction, and quality assessment using Downs and Black's (1998) scoring system were performed. The inverse variance random-effect approach was used to pool the results, and statistical heterogeneity was evaluated using I-squared statistics. Results: Fifteen studies were included for qualitative synthesis, five of which were pooled for quantitative analysis. The risk ratio (RR) of sharing only one genotype in caries-free children versus children with caries was found to be 0.60 (95 percent confidence interval [95% CI] equals 0.45 to 0.80; P ≤ 0.001). The RR of sharing more than one genotype was 1.46 (95% CI equals 1.13 to 1.89; P=0.004) in children with caries versus caries-free children. These findings imply that children sharing only one genotype have a 40 percent lesser risk, and children sharing more than one genotype have a 46 percent higher risk of having dental caries. Conclusions: The systematic review provides evidence of the horizontal transmission of S. mutans and its association with dental caries.

Combined effect of arginine and fluoride on the growth of Lactobacillus rhamnosus GG.

The objectives of the in vitro study were: (1) to investigate the effect of combining L-arginine (Arg) and NaF on the growth of Lactobacillus rhamnosus GG (LRG); and (2) to identify an optimum synergistic concentration for the synbiotic (Arg + LRG)-fluoride (SF) therapy. 1% Arg + 2000-ppm NaF (A-SF) and 2% Arg + 2000-ppm NaF (B-SF) demonstrated antagonism against LRG (FIC > 4.0). Both XTT (2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide) and WST-8 (2-(2-methoxy-4-nitrophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium, monosodium salt) assays showed that A-SF and B-SF enhanced the growth of LRG when compared to 2000-ppm NaF and LRG control. Colony forming units, bacterial weight, and biofilm thickness of A-SF and B-SF were significantly higher than 2000-ppm NaF and LRG control. Biofilm imaging depicted that 2000-ppm NaF inhibited biofilm formation; while 1%/2% Arg, A-SF, and B-SF increased biofilm growth of LRG. Lactic acid formation was the lowest for 2000-ppm NaF, followed by A-SF and then B-SF. The SF buffer potential after 24 h was the highest for B-SF, and then A-SF. Biofilm pH for B-SF was closest to neutral. Fluoride, Arg and LRG bioavailability remained unaffected in B-SF. The relative gene expression for arcA, argG, and argH was significantly higher for B-SF than the respective controls. In conclusion, combining 2% Arg, 2000-ppm NaF, and LRG provides an optimum synbiotic-fluoride synergism.

Using next-generation sequencing to detect oral microbiome change following periodontal interventions: A systematic review.

OBJECTIVES: This systematic review was to evaluate the change of oral microbiome based on next-generation sequencing (NGS)-metagenomic analysis following periodontal interventions among systematically healthy subjects. MATERIALS AND METHODS: A structured search strategy consisting of "metagenomics" and "oral diseases" was applied to PubMed, EMBASE, and Web of Science to identify effective papers. The included studies were original studies published in English, using metagenomic approach to analyze the effectiveness of periodontal intervention on oral microbiome among systematically healthy human subjects with periodontitis. RESULTS: A total of 12 papers were included in this review. Due to the heterogeneity of selected study, quantitative analysis was not performed. The findings as to how alpha diversity changed after interventions were not consistent across studies. Six studies illustrated clear separation of microbial composition between dental plaque samples collected before and after intervention using principal coordinates/component analysis. The most commonly detected genera before intervention were Porphyromonas, Treponema, Tannerella, and Prevotella, while Streptococcus and Actinomyces usually increased and became the dominant genera after intervention. Correlation network analysis revealed that after intervention, the topology of network was different compared to the corresponding pre-interventional samples. CONCLUSION: Existing evidence of metagenomic studies depicts a complex change in oral microbiome after periodontal intervention.

Global Perspectives of Oral Health Policies and Oral Healthcare Schemes for Older Adult Populations.

The aim of this study was to present a concise summary of the oral health policies and oral healthcare schemes for older adult populations in a number of selected countries around the world. In this paper, the current and planned national/regional oral health policies and oral healthcare schemes of nine countries (Australia, Brazil, China including Hong Kong, India, Japan, Switzerland, Thailand, the United Kingdom, and the United States) are reported. Barriers and challenges in oral health promotion in terms of devising oral health policies, implementing oral health schemes, and educating the future dental workforce are discussed. In response to the aging of population, individual countries have initiated or reformed their healthcare systems and developed innovative approaches to deliver oral health services for older adults. There is a global shortage of dentists trained in geriatric dentistry. In many countries, geriatric dentistry is not formally recognized as a specialty. Education and training in geriatric dentistry is needed to produce responsive and competent dental professionals to serve the increasing number of older adults. It is expected that oral health policies and oral healthcare services will be changing and reforming in the coming decades to tackle the enduring oral health challenges of aging societies worldwide.

Inter-method reliability for determining total and soluble fluorides in child low-fluoride formula dentifrices.

The study aimed to compare three methods for determining total (TF) and total soluble fluorides (TSF) in 5 child formula dentifrices (CFD) using Inter-method reliability (IMR) statistical approach. The methods were direct acid-hydrolysis (DM), the least-time-consuming method; Modified direct acid-hydrolysis with standard-addition method (MDM), ISO 19448:2018 method; and modified Taves acid-HMDS diffusion analysis (TAD), the claimed gold standard method. A significant difference in the mean difference was observed for all methods at all levels (p < 0.001), except DM and TAD for TF (p = 0.622). A proportional bias was discerned in the agreement distribution between DM and TAD for TF (p < 0.001). The ICC analysis identified significant reliability between all measurements, irrespective of the model, measure, and fluoride type (p < 0.001). For TF and TSF, the IMR between DM and TAD was lower than MDM and TAD for consistency/absolute agreement reliability at single/average measures. The reliability measure for DM and MDM was higher than MDM and TAD for TSF, but was lower than MDM and TAD for TF. The ICC measure for DM-TAD was significantly lower than DM-MDM and MDM-TAD (p < 0.05). The ISO 19448:2018 MDM is a reliable test that can be used as an alternative to TAD/DM for determining TF/TSF in CFD.

Enhanced Fluoride Bioavailability with Incorporation of Arginine in Child Dentifrices.

OBJECTIVE(S): To: 1) examine the fluoride concentrations in commercial child formula dentifrices (CFD)s; and 2) investigate the effect of arginine incorporation in CFDs on fluoride bioavailability. STUDY DESIGN: Five commercial CFDs were examined for fluoride concentrations. Total, total soluble, and insoluble fluorides in CFDs were determined by the modified Taves acid-diffusion method (TAD). Ionic F and MFP were estimated by modified direct method with standard addition technique. L-arginine (L-Arg)/L-arginine monohydrochloride (L-Arg.HCl) were incorporated at 2% w/w in the commercial CFDs. The pH of the toothpaste slurries, buffer capacity of the added Arg, potentially available fluorides (PAF) and 1-min PAF by TAD were determined. RESULTS: The CFDs had 4 to 32% of insoluble fluorides. Addition of L-Arg/L-Arg.HCl significantly improved the fluoride bioavailability in CFDs (p<0.05). Incorporation of L-Arg significantly increased the pH of toothpaste slurries (p<0.05); while L-Arg.HCl decreased the pH. Principal component analysis showed that L-Arg.HCl decreased the pH of toothpaste slurries due to the presence of Cl in the form of HCl; whereas the inherent elements/molecules (Na/P/Pi/F) remain distinct with unidentified influence on the variables. CONCLUSION(S): The CFDs containing NaF only have higher concentrations of bioavailable fluoride. Incorporating arginine (L-arginine or L-arginine monohydrochloride) at 2% w/w improves fluoride bioavailability of the child formula dentifrices.

Effect of silver diamine fluoride on plaque microbiome in children.

OBJECTIVE: To investigate the microbiome profile and relative abundance changes of the plaque on silver diamine fluoride (SDF)-treated caries in children with early childhood caries. METHODS: A single trained examiner assessed the caries as being arrested or active and then collected plaque samples from the caries lesions from fourteen 5-year-old children immediately before, 2 weeks after, and 12 weeks after a one-off application of 38 % SDF. We assigned 16S rRNA gene sequences to operational taxonomic units (OTUs) using a 98.5 % identity cut-off. We also used a variety of taxonomy- and phylogeny-based statistical approaches to compare the biodiversity and relative abundance among different groups. RESULTS: The caries arrest rate were 90 % and 83 % after 2 and 12 weeks, respectively. We studied 46 plaque samples and identified 388 OTUs (254 identified at the species level, 129 identified at the genus level, and 76 identified at the family level). There was no significant change in the diversity in the arrested caries before and 12 weeks after SDF treatment (p = 0.71). The diversity in active caries reduced significantly 12 weeks after SDF treatment (p = 0.006). The relative abundance of certain caries-related species (e.g., Streptococcus mutans and Lactobacillus sp.) was reduced in arrested caries but was increased in active caries after SDF treatment. CONCLUSION: There was no overall microbiome changes in the caries arrested by SDF. The relative abundance of some caries-related species is reduced in arrested caries, while increased in active caries. CLINICAL SIGNIFICANCE: This study provides information on microbiome changes on SDF-treated caries of children.

Synbiotics in caries prevention: A scoping review.

The scoping review aimed to examine the evidence on the role of synbiotics in caries prevention. PubMed, SCOPUS, and Web of Science databases search were performed. Any in vitro study, clinical trial, systematic review with/without meta-analysis, umbrella review/meta-evaluation, narrative review addressing the role of synbiotics in caries prevention were included in the scoping review. Data were extracted from the included studies using pre-approved registered protocol. Twenty-eight records were identified, of which 5 in vitro studies, 1 quasi-experimental clinical trial and 1 narrative review were included in the present review. No controlled clinical trials or systematic reviews on the role of synbiotics in caries prevention could be identified. Except 1, all in vitro studies examined the combined effect of saccharides and lactobacilli spp. as potential synbiotics on the growth of Streptococcus mutans. However, the proposed synbiotics in 4 in vitro studies either did not qualify or remained ambiguous of its eligibility as a potential synbiotic for caries prevention. One recent in vitro study explored the possibility of L-arginine and Lactobacillus rhamnosus GG synbiotic for caries prevention. The quasi-experimental clinical study without a control arm did not explicitly mention the intervention composition and thus, its synbiotic potential remains unclear. A narrative review highlighted the potential of combining arginine (prebiotic) with arginolytic bacteria (probiotic) as a synbiotic, which appears promising for caries prevention. The eligibility of the proposed synbiotics as a true synbiotic needs to be carefully addressed. Due to a lack of controlled clinical studies on synbiotics for caries prevention, evidence on their caries-preventive potential is weak. Future studies are needed to examine the combination of amino acids (esp. arginine) with probiotics as a potential synbiotic against cariogenic pathogens.

Using metagenomic analysis to assess the effectiveness of oral health promotion interventions in reducing risk for pneumonia among patients with stroke in acute phase: study protocol for a randomized controlled trial.

BACKGROUND: The prevalence of pneumonia complicating stroke in acute phase has a poor prognosis and higher risk for death. Oral opportunistic pathogens have been reported to be associated with pneumonia among people with compromised health. Oral health promotion is effective in reducing dental plaque among patients with stroke, which is considered as reservoirs for oral opportunistic pathogens. This study evaluates the effectiveness of oral health promotions in reducing the prevalence of pneumonia via its effects on composition and relative abundance of oral opportunistic pathogens. METHODS/DESIGN: This study is a randomized, single-blind, parallel trial of 6 months duration. The study is being conducted at one of the largest medical teaching hospitals in Hefei, China. A total of 166 patients with stroke and free from any post-stroke complication will be recruited. After enrollment, patients will be randomized to one of the following groups: (1) oral hygiene instruction (OHI) or (2) OHI, 6-month use of powered tooth brushing, and 0.2% chlorhexidine gluconate mouth rinse (10 ml twice daily). The primary outcome is the prevalence of pneumonia complicating stroke. Patients will be monitored closely for any occurrence of pneumonia over the entire period of this trial. Oral rinse samples will be collected at baseline and multiple follow-up reviews (3, 5, 7 days, and 1, 3, 6 months after baseline). Next-generation sequencing will be employed to detect composition and relative abundances of the microorganism in the oral rinse samples. Questionnaire interviews and clinical oral examinations will be conducted at baseline and 1, 3, and 6 months after baseline. DISCUSSION: The findings of this trial will provide evidence whether oral health promotion intervention is effective in reducing the prevalence of pneumonia complicating stroke via its effect on the oral microbiome. The analysis of the outcomes of this trial is empowered by metagenomic analysis at 16S rRNA level, which is more sensitive and comprehensive to help us detect how oral health promotion inventions affect the oral microbiome in terms of its composition, relative abundance, and interactions between species, which all may contribute to the occurrence of pneumonia complicating stroke. TRIAL REGISTRATION: ClinicalTrials.gov NCT04095780 . Registered on 19 September 2019.

Antibacterial and mechanical properties of arginine-containing glass ionomer cements.

OBJECTIVE: The study investigated the effect of incorporating l-arginine (Arg) in a glass ionomer cement (GIC) on its mechanical properties and antibacterial potential. METHODS: Pre-determined proportions (1%, 2%, and 4% by wt.) of Arg were incorporated in GIC powder; while GIC without Arg served as control. The flexural strength, nanohardness, surface roughness, elemental analysis using SEM-EDX (n = 6) and F/Arg/Ca/Al/Si release in deionized water for 21 days were assessed. The antibacterial potential was evaluated in a multi-species biofilm model with Streptococcus mutans, Streptococcus sanguinis, Streptococcus gordonii, and Lactobacillus acidophilus for 72 h. Real-time qPCR was used to analyse biofilm bacterial concentrations. Propidium monoazide modification of real-time qPCR was performed to quantify viable/dead bacteria. The pH, lactic acid, ADS activity, and H2O2 metabolism were measured. Confocal microscopy was used to investigate the biofilm bacterial live/dead cells, density, and thickness. RESULTS: There was no difference in flexural strength among the different groups (p > 0.05). No significant difference in nanohardness and surface roughness was observed between 4% Arg + GIC and control (p > 0.05). The 4% Arg + GIC showed significantly higher F/Arg/Al/Si release than the other groups (p < 0.05), reduced total bacterial concentration and growth inhibition of viable S. mutans and S. sanguinis (p < 0.05). Lactic acid formation for 4% Arg + GIC was significantly higher than 1% Arg + GIC (p < 0.05). The spent media pH of 4% Arg + GIC was higher than the other groups (p < 0.05), with proportionately lower ammonia and higher H2O2 released (p < 0.05). SIGNIFICANCE: Addition of 4% l-arginine in GIC enhanced its antibacterial activity via a biofilm modulatory effect for microbial homeostasis, with no detrimental effect on its mechanical properties.