Water fluoridation for the prevention of dental caries.

BACKGROUND: Dental caries is a major public health problem in most industrialised countries, affecting 60% to 90% of school children. Community water fluoridation (CWF) is currently practised in about 25 countries; health authorities consider it to be a key strategy for preventing dental caries. CWF is of interest to health professionals, policymakers and the public. This is an update of a Cochrane review first published in 2015, focusing on contemporary evidence about the effects of CWF on dental caries. OBJECTIVES: To evaluate the effects of initiation or cessation of CWF programmes for the prevention of dental caries. To evaluate the association of water fluoridation (artificial or natural) with dental fluorosis. SEARCH METHODS: We searched CENTRAL, MEDLINE, Embase and four other databases up to 16 August 2023. We also searched two clinical trials registers and conducted backward citation searches. SELECTION CRITERIA: We included populations of all ages. For our first objective (effects of initiation or cessation of CWF programmes on dental caries), we included prospective controlled studies comparing populations receiving fluoridated water with those receiving non-fluoridated or naturally low-fluoridated water. To evaluate change in caries status, studies measured caries both within three years of a change in fluoridation status and at the end of study follow-up. For our second objective (association of water fluoridation with dental fluorosis), we included any study design, with concurrent control, comparing populations exposed to different water fluoride concentrations. In this update, we did not search for or include new evidence for this objective. DATA COLLECTION AND ANALYSIS: We used standard methodological procedures expected by Cochrane. For our first objective, we included the following outcomes as change from baseline: decayed, missing or filled teeth ('dmft' for primary and 'DMFT' for permanent teeth); decayed, missing or filled tooth surfaces ('dmfs' for primary and 'DMFS' for permanent teeth); proportion of caries-free participants for both primary and permanent dentition; adverse events. We stratified the results of the meta-analyses according to whether data were collected before or after the widespread use of fluoride toothpaste in 1975. For our second objective, we included dental fluorosis (of aesthetic concern, or any level of fluorosis), and any other adverse events reported by the included studies. MAIN RESULTS: We included 157 studies. All used non-randomised designs. Given the inherent risks of bias in these designs, particularly related to management of confounding factors and blinding of outcome assessors, we downgraded the certainty of all evidence for these risks. We downgraded some evidence for imprecision, inconsistency or both. Evidence from older studies may not be applicable to contemporary societies, and we downgraded older evidence for indirectness. Water fluoridation initiation (21 studies) Based on contemporary evidence (after 1975), the initiation of CWF may lead to a slightly greater change in dmft over time (mean difference (MD) 0.24, 95% confidence interval (CI) -0.03 to 0.52; P = 0.09; 2 studies, 2908 children; low-certainty evidence). This equates to a difference in dmft of approximately one-quarter of a tooth in favour of CWF; this effect estimate includes the possibility of benefit and no benefit. Contemporary evidence (after 1975) was also available for change in DMFT (4 studies, 2856 children) and change in DMFS (1 study, 343 children); we were very uncertain of these findings. CWF may lead to a slightly greater change over time in the proportion of caries-free children with primary dentition (MD -0.04, 95% CI -0.09 to 0.01; P = 0.12; 2 studies, 2908 children), and permanent dentition (MD -0.03, 95% CI -0.07 to 0.01; P = 0.14; 2 studies, 2348 children). These low-certainty findings (a 4 percentage point difference and 3 percentage point difference for primary and permanent dentition, respectively) favoured CWF. These effect estimates include the possibility of benefit and no benefit. No contemporary data were available for adverse effects. Because of very low-certainty evidence, we were unsure of the size of effects of CWF when using older evidence (from 1975 or earlier) on all outcomes: change in dmft (5 studies, 5709 children), change in DMFT (3 studies, 5623 children), change in proportion of caries-free children with primary dentition (5 studies, 6278 children) or permanent dentition (4 studies, 6219 children), or adverse effects (2 studies, 7800 children). Only one study, conducted after 1975, reported disparities according to socioeconomic status, with no evidence that deprivation influenced the relationship between water exposure and caries status. Water fluoridation cessation (1 study) Because of very low-certainty evidence, we could not determine if the cessation of CWF affected DMFS (1 study conducted after 1975; 2994 children). Data were not available for other review outcomes for this comparison. Association of water fluoridation with dental fluorosis (135 studies) The previous version of this review found low-certainty evidence that fluoridated water may be associated with dental fluorosis. With a fluoride level of 0.7 parts per million (ppm), approximately 12% of participants had fluorosis of aesthetic concern (95% CI 8% to 17%; 40 studies, 59,630 participants), and approximately 40% had fluorosis of any level (95% CI 35% to 44%; 90 studies, 180,530 participants). Because of very low-certainty evidence, we were unsure of other adverse effects (including skeletal fluorosis, bone fractures and skeletal maturity; 5 studies, incomplete participant numbers). AUTHORS' CONCLUSIONS: Contemporary studies indicate that initiation of CWF may lead to a slightly greater reduction in dmft and may lead to a slightly greater increase in the proportion of caries-free children, but with smaller effect sizes than pre-1975 studies. There is insufficient evidence to determine the effect of cessation of CWF on caries and whether water fluoridation results in a change in disparities in caries according to socioeconomic status. We found no eligible studies that report caries outcomes in adults. The implementation or cessation of CWF requires careful consideration of this current evidence, in the broader context of a population's oral health, diet and consumption of tap water, movement or migration, and the availability and uptake of other caries-prevention strategies. Acceptability, cost-effectiveness and feasibility of the implementation and monitoring of a CWF programme should also be taken into account.

Content analysis of fluoride-related posts on Instagram.

BACKGROUND: The Internet and social media have become many people's primary sources of health information. Instagram is one of the most popular social media platforms, and users spend a significant amount of time daily on the platform. Therefore, analyzing oral health-related information shared online can help to identify the requirements of specific groups, assisting in the planning and execution of educational public health actions. As a result, this study was carried out to conduct a qualitative evaluation of fluoride-related content on Instagram in 2022-2023. METHODS: Using hashtags associated with fluoride, a search was conducted on the Instagram application in the Persian language. All fluoride-containing posts were saved, and data was collected thrice at two-month intervals. MAXQDA software version 2020 was used to categorize the collected data content based on type, quality, and quantity. RESULTS: The qualitative analysis included 1565 (9.45%) posts with fluoride-related content out of 16,475 total posts. After removing the duplicates, 400 posts remained, among which 282 posts (70.5%) and 118 posts (29.5%) were pro- and anti-fluoride, respectively. After qualitative analysis, 270 codes were examined and categorized into three main themes and eight subthemes: "fluoride sources," "The advantages and disadvantages of fluoride," and "Invalid beliefs about fluoride." CONCLUSION: The frequency of pro-fluoride use was higher than anti-fluoride posts. However, due to the high prevalence of posts containing false information on fluoride toxicity for health, ineffectiveness on caries prevention, and conspiracy theories, there is a need to improve the quality of information on fluoride by providing scientific and unbiased explanations by professionals online or during dental visits and supervising social media content.

Long-term costs of dental care for thailand preschool children by using a system dynamics model.

BACKGROUND: A System Dynamics Model (SDM) is a computer simulation to alleviate the problem by comparing strategies and policies. Addressing the costs by using SDM helps in allocating the resources efficiently in managing the strategies. OBJECTIVE: To describe the costs of primary, secondary, and tertiary prevention of dental caries for 0-5-year-old children by SDM. METHODS: The SDM was developed to explore the cost of primary and secondary prevention (supervised toothbrushing, STB and fluoride varnish, FV), the treatment cost for caries (tertiary prevention), and the total cost under three scenarios; STB, FV and base case (no intervention). RESULTS: When the children aged 5 years, the treatment cost under the base case was the highest at 57.6 million baht while 53.5 million baht in FV and 51.9 million baht in STB. As a total cost, 64.1 million baht under FV, 60.9 million baht under STB, and 57.6 million baht under base case. Sensitivity analysis reveals that the effective rate of STB must be at least 30%, and FV should be a minimum of 50% to ascertain the total cost reduction relative to the base case scenario. CONCLUSION: Caries treatment costs were lower when STB and FV were implemented than in the base case scenario. The overall cost under FV was the highest, followed by STB, with no total cost savings observed as compared to the base case situation. Despite that, carrying out the STB rather than the FV would save a total of 3.2 million baht. Treatment costs under interventions would be lower than expected, and overall cost reductions might be obtained by comparing the base case if the intervention's effective rates are higher, according to sensitivity analysis.

The effectiveness of Bio-Min toothpaste in the management of white spot lesions: a randomised control trial.

BACKGROUND: White spot lesions (WSL) are common side effects of orthodontic treatment with fixed appliances, in which the surface layer of enamel is demineralised. Thus, remineralisation, that is a partial or complete reversal, of these lesions can occur as they affect the surface enamel. Remineralisation with low-dose fluoride, in addition to optimal oral hygiene and diet, has been recommended to manage WSL. The aim of the planned trial is to assess the effectiveness of a fluoride-containing bioactive glass toothpaste (BioMin™) in its ability to remineralise post-orthodontic demineralised WSL. METHODS: A single-centre, double-blind randomised clinical trial to assess intervention with Bio-Min toothpaste on WSL forming on the teeth of young people completing orthodontic treatment. DISCUSSION: Remineralisation of WSL can vary depending on the individual and the site of the lesion. There is a range of oral fluoride delivery methods which include toothpastes, oral rinses, and gel preparations, which can aid remineralisation of these lesions. Identifying effective methods of remineralisation to manage this common and unsightly complication of fixed appliance therapy can improve the health and aesthetics of dentition. TRIAL REGISTRATION: ISRCTN.com International Standard Randomised Controlled Trials Number (ISRCTN) 14479893 . Registered on 14 May 2020.

Effect of Fluoride-releasing Resin Cement on the Development of White Spot Lesions Around Orthodontic Brackets - A Retrospective Study.

AIMS: This study aimed to assess the effect of G-CEM, a fluoride-releasing cement, on the development of white spot lesions (WSLs) and their severity around orthodontic brackets. METHODS AND MATERIALS: This case-control study was conducted by reviewing 140 dental records of fixed orthodontic patients presenting to an orthodontic clinic. The patients were assigned to two groups ( n = 70). In group 1, Transbond XT resin cement, and in group 2, G-CEM had been used for bracket bonding. The frequency and severity of WSLs in each group were evaluated by assessing the available post-treatment photographs of patients and notes left by their orthodontist in their records in this regard. The number of teeth with WSLs in each patient was recorded, and the severity of lesions was categorised by Gorelick's analysis. STATISTICAL ANALYSIS: Comparisons were made using independent t -test, Wilcoxon test and Mann-Whitney test (alpha = 0.05). RESULTS: In both the maxilla and mandible, the prevalence of WSLs was significantly higher in the Transbond XT group than in the G-CEM group ( P = 0.01). The difference in frequency of WSLs between the maxilla and mandible was not significant within each group ( P > 0.05). Tooth #22 had the highest frequency of WSLs (11.4%) in the Transbond XT group, while teeth #12 and #36 had the highest frequency of WSLs (2.9%) in the G-CEM group. The difference in frequency of WSLs was not significant between males and females ( P > 0.05). CONCLUSION: Bracket bonding with G-CEM fluoride-releasing cement significantly reduced the development of WSLs around orthodontic brackets.

Bleaching as a complement to fluoride-enhanced remineralization or resin infiltration in masking white spot lesions.

OBJECTIVE: There are many suitable strategies for addressing caries, which is an ongoing worldwide problem. Although white spot lesions (WSLs) can be either remineralized naturally or treated with non- or micro-invasive strategies, their whitish and opaque appearance may persist. To evaluate the effects of tooth bleaching as a complement to fluoride-enhanced remineralization or resin infiltration in masking WSLs, as well as in enamel surface roughness relative to that of the adjacent enamel. METHODOLOGY: Flattened rectangular bovine enamel fragments (6×3×~2.9 mm length, width and thickness) were divided into six groups (L/N, F/N, F.BL/BL, I/N, I.BL/BL, N/N; n=15). Treatments applied to the 3×3 mm left half included: L (Lesion) - WSL simulation with 50 mM acetate buffer, 96 hours, 37ºC; F (Fluoride) - WSL treatment with 2% NaF neutral gel, 1x/week, 8 weeks; I (Infiltration) - WSL treatment with H3PO4 37%/10 s; Icon®-Dry/30 s; Icon®-Infiltrant/3 min+1 min; N (Nothing) - sound enamel/control. Treatments applied to both halves after F and I included: BL (Bleaching) - Opalescence Boost 40%, 3×/20 min each; N (Nothing) - control. The differences in color (ΔE00, ΔL, Δa, Δb) and surface roughness (ΔRa) between the left and right halves were measured. Kruskal-Wallis/post-hoc tests were applied to ΔE00, ΔL, Δa and ΔRa, and 1-way ANOVA/Tukey tests to Δb (α=0.05). RESULTS: The factor under study significantly influenced ΔE00 (p=0.0001), ΔL (p=0.0024), Δb (p=0.0015), and ΔRa (p<0.001), but not Δa (p=0.1592). Both fluoride-enhanced remineralization and resin infiltration were able to mask WSL, regardless of subsequent bleaching. However, when bleaching was performed, ΔE00 median values did not exceed the acceptability threshold for color difference. Only resin infiltration reduced ΔRa between WSL and the adjacent enamel. CONCLUSIONS: Both remineralization and infiltration, particularly if complemented by bleaching, fostered satisfactory esthetic results. Only infiltration without bleaching led to really good results in surface roughness.

In-vitro and in-vivo comparative studies of treatment effects on enamel demineralization during orthodontic therapy: implications for clinical early-intervention strategy.

OBJECTIVES: This study aimed to investigate if CPP-ACP / infiltrating resin was superior in treating enamel demineralization during orthodontic therapy compared with fluoride varnish, in order to provide early-intervention implications for dental professionals. MATERIALS AND METHODS: In the in-vitro study, premolars were grouped into four: remineralization with fluoride varnish / CPP-ACP, sealing with infiltrating resin, and negative control. Experimental demineralization of enamel surfaces was analyzed using techniques of QLF, SEM, EDS and micro-hardness testing. An in-vivo intervention study was conducted on patients randomly assigned into three groups. At the baseline and every-3-month follow-up, QLF parameters were compared temporally and parallelly to yield potential implications for promotion in clinical practice. RESULTS: The in-vitro study performed on 48 experimental tooth surfaces demonstrated that sealing with infiltrating resin reduced enamel surface porosity and increased surface micro-hardness significantly. In the in-vivo intervention study on 163 tooth surfaces, it was suggested that for those who meet the criteria of -10 < ΔF < -6 and - 1000 < ΔQ < -20 at the baseline, all these treatment methods could achieve acceptable outcomes; with the rising of absolute values of ΔF and ΔQ, sealing with infiltrating resin showed more evident advantages. CONCLUSION: For enamel demineralization during orthodontic therapy, all the treatment methods involved in this study showed acceptable effectiveness but had respective characteristics in treatment effects. QLF parameters could be used as indicators for clinical early-intervention strategy with regards to this clinical issue. CLINICAL RELEVANCE: With QLF parameters, clinical early-intervention strategy for enamel demineralization during orthodontic therapy could be optimized.

An open-label, parallel-group, randomized clinical trial of different silver diamine fluoride application intervals to arrest dental caries.

BACKGROUND: Silver diamine fluoride (SDF) is an antimicrobial agent and alternative treatment option that can be used to arrest dental decay. While there is optimism with SDF with regard to caries management, there is no true consensus on the number and frequency of applications for children. The purpose of this study was to examine the effectiveness of 38% SDF to arrest early childhood caries (ECC) at three different application regimen intervals. METHODS: Children with teeth that met International Caries Detection and Assessment System codes 5 or 6 criteria were recruited from community dental clinics into an open-label, parallel-group, randomized clinical trial from October 2019 to June 2021. Participants were randomized to one of three groups using sealed envelopes that were prepared with one of three regimens inside: visits one month, four months, or six months apart. Participants received applications of 38% SDF, along with 5% sodium fluoride varnish (NaFV), at the first two visits to treat cavitated carious lesions. Lesions were followed and arrest rates were calculated. Lesions were considered arrested if they were hard on probing and black in colour. Statistics included descriptive and bivariate analyses (Kruskal one-way analysis of variance and Pearson's Chi-squared test). A p-value of ≤ 0.05 was considered significant. RESULTS: Eighty-four children participated in the study (49 males and 35 females, mean age: 44.4 ± 14.2 months). Treatment groups were well matched with 28 participants per group. A total of 374 teeth and 505 lesions were followed. Posterior lesions represented only 40.6% of affected surfaces. Almost all SDF treated lesions were arrested for the one-month (192/196, 98%) and four-month (159/166, 95.8%) interval groups at the final visit. The six-month group experienced the lowest arrest rates; only 72% (103/143) of lesions were arrested (p < 0.001). The duration of application intervals was inversely associated with improvements in arrest rates for all lesions. CONCLUSIONS: Two applications of 38% SDF and 5% NaFV in one-month and four-month intervals were comparable and very effective in arresting ECC. Applications six months apart were less effective and could be considered inferior treatment. TRIAL REGISTRATION: ClinicalTrials.gov NCT04054635 (first registered 13/08/2019).

Kinetics of fluoride after brushing with the no-rinse method.

BACKGROUND: Fluoride plays a vital role in preventing dental caries, with its addition to oral care products significantly promoting oral hygiene. A no-rinse brushing method aims to increase fluoride retention in the oral cavity, as rinsing with water decreases fluoride levels in saliva, which could affect remineralization. While the no-rinse brushing method holds promise for improving fluoride retention in the oral cavity, critical inquiries persist regarding its safety. This study investigated the kinetics of oral fluoride and potential risks to fully assess its effectiveness and implications for oral health. METHODS: Ten healthy adults participated in a crossover study comparing the no-rinse with the rinse method. All subjects followed American Dental Association (ADA) brushing guidelines. Levels of fluoride in saliva (supernatant and sediment) and urine were measured over time, and plasma fluoride was measured one hour after brushing. Pharmacokinetic parameters were also calculated from the data. RESULTS: Participants using the no-rinse method had higher fluoride levels in supernatant immediately and up to 30 min post-brushing compared to the rinse method. Fluoride levels in sediment were higher only immediately after brushing. The total fluoride concentration in saliva remained elevated for up to 5 min with the no-rinse method. Systemic fluoride absorption showed no significant difference between the two methods based on blood and urine analysis. CONCLUSION: This research indicates that the no-rinse method can enhance fluoride retention in the oral cavity for up to 30 min after a single brushing. In addition, our findings suggest that this method does not significantly influence systemic fluoride levels or toxicity. REGISTRY: Thai Clinical Trials Registry, TCTR ( http://thaiclinicaltrials.org ). CLINICAL TRIAL REGISTRATION NUMBER: TCTR20231104001 (4/11/2023).

Effectiveness of silver diamine fluoride (SDF) in arresting coronal dental caries in children and adolescents: a systematic review.

Dental caries remains a significant public health issue for children globally, leading to adverse effects on health and development. Silver diamine fluoride (SDF) is a potential preventive agent that can prevent caries progression in children. This systematic review examined the effectiveness of silver diamine fluoride in arresting caries compared to other fluorides. An electronic search of MEDLINE, PubMed, EMBASE, Cochrane, Web of Science, Scopus databases was carried out examining articles in English from 2001 to 2023. Studies included in the analysis examined the application of SDF in children and adolescents with coronal caries lesions on primary teeth or permanent first molars. Fifteen studies, involving a total of 7895 children, were incorporated. The application regimen varied across studies. Most studies in this review consistently suggested that SDF is effective in arresting caries. An annual application of SDF effectively reduced Streptococcus mutans count. Adverse effects were primarily tooth staining and less commonly, oral mucosal irritation. A majority of studies showed a high risk of bias due to methodological insufficiencies. Overall, the evidence suggests that SDF is effective in arresting dental caries in children. It offers a viable, cost-effective, and minimally invasive treatment option, particularly suitable for use in low-resource settings. However, the aesthetic concern of tooth staining with SDF use remains a challenge. Further well-designed clinical trials may provide a fuller picture of SDF which can shape public health policy and shift towards a minimally invasive treatment approach.

Effect of adding sodium fluoride and nano-hydroxyapatite nanoparticles to the universal adhesive on bond strength and microleakage on caries-affected primary molars.

Evaluation of micro tensile bond strength (µTBS) and marginal leakage of sodium fluoride (NaF) and nano-hydroxyapatite (n-HA) modified universal adhesives (UAs) bonded using etch-and-rinse (ER) and self-etch (SE) bonding technique to the carious affected dentin (CAD). One hundred and twenty primary molars were prepared for CAD on the occlusal surface. The occlusal CAD surface was flattened and underwent a polishing procedure. The specimens were divided into six groups using a random allocation method based on the UAs applied and the mode of etching used (n = 20) Group A1: UAs (ER), Group B1: UAs (SE), Group A2: UAs (NaF) + ER, Group B2: UAs (NaF) + SE, Group A3: UA (n-HA) + ER and Group B3: UAs (n-HA) + SE. Composite restoration was placed and samples were thermocycled. Microleakage, µTBS, and failure mode assessment were performed using a dye penetration test, universal testing equipment, and stereomicroscope respectively. The µTBS and microleakage results (mean ± SD) were examined using analysis of the variance (ANOVA) and Tukey post hoc tests. Group B1 (UAs + SE) demonstrated the maximum scores of microleakage (25.14 ± 9.12 nm) and minimum recorded value of µTBS (14.16 ± 0.55 MPa). In contrast, Group A3 (UAs (n-HA) + ER) displayed a minimum value of marginal leakage (12.32 ± 6.33 nm) and maximum µTBS scores (19.22 ± 0.92 MPa). The outcomes of the intergroup comparison analysis showed that Group A2 (UAs (NaF) + ER), Group B2 (UAs (NaF) + SE), Group A3 (UA (n-HA) + ER) and Group B3 (UAs (n-HA) + SE) presented comparable outcomes of marginal seal outcomes and µTBS scores (p > 0.05). NaF and n-HA-modified UAs displayed favorable bond strength and minimum marginal leakage to the deciduous affected dentin surface.

Evaluation of nanohardness, elastic modulus, and surface roughness of fluoride-releasing tooth colored restorative materials.

Recently, interest in tooth-colored fluoride-releasing dental materials has increased. Although physical and mechanical properties such as surface hardness, elastic modulus and surface roughness of the restorative materials have been investigated, the effect of different immersion media on these properties is still controversial. The aim of this study was to evaluate the nanohardness, elastic modulus and surface roughness of the fluoride release of tooth-colored restorative materials after immersion in acidic beverages. Prepared samples of three restorative materials (a highly viscous glass ionomer (EQUIA Forte; GC, Tokyo, Japan), a compomer (Dyract XP; Dentsply, Weybridge, UK), and a bioactive restorative material (Activa BioACTIVE; Pulpdent, MA, USA)) were randomly divided and immersed in distilled water, a cola and an orange juice for one week. The HYSITRON T1 950 TriboIndenter device (Hysitron, USA) with the Berkovich diamond indenter tip was used for all measurements. The nanohardness and elastic modulus of the samples were measured by applying a force of 6000 µN to five different points on the sample surface. Surface roughness measurements were evaluated on random samples by scanning five random 40 × 40 µm areas. The properties were measured at the initial and one week after immersion. The values of nanohardness, elastic modulus and surface roughness were tested for significant differences using a two-way analysis of variance (ANOVA) with repeated measures (p < 0.05). Tukey's honest significant difference (HSD) test was used for multiple comparisons. AB (Activa BioACTIVE) had the highest initial mean values for nanohardness. After post-immersion, the highest mean value for elastic modulus was the initial AB value. The lowest mean value for roughness of 100.36 nm was obtained for the initial DX (Dyract XP) measurement. Acidic beverages had a negative effect on the nanohardness, elastic modulus and surface roughness of the restorative materials.

Can silver diamine fluoride reduce invasive treatments with general anesthesia?

This study aims to retrospectively evaluate the differences in dental treatments rendered in general anesthesia (GA) for patients who did or did not receive application of silver diamine fluoride (SDF) prior to GA. 1559 patients (≤6 years) who completed treatment with GA for caries at University of California San Francisco (UCSF) between 2015 and 2019 were included in the study. At baseline patients' electronic health record was reviewed to collect planned treatment, complete dental treatment and demographics. Patients were identified as SDF group (N = 335, 21.49%) or comparison (N = 1224, 78.51%). Dental treatments rendered were compared between the SDF and comparison group with multi-variable regression, including variables for demographics and clinical findings at baseline. The initial analysis identified variations in gender, age, dental pain, pulp involvement, and initial treatment plans between the SDF and comparison groups at baseline. In an unadjusted analysis, the SDF group displayed a statistically significant increase in the number of crown procedures but a notable decrease in the number of pulp therapy and extraction treatments completed (p < 0.05). An adjusted multivariable model affirmed the inverse relationship between SDF application and completion of pulp therapy and extractions at the time of GA (p < 0.05). No significant association was identified with the total number of crowns needed and SDF. The model further indicated a positive correlation between the total count of pulp therapy and extractions completed with patient age and the wait-time for GA. In conclusion, pre-GA application of SDF to carious primary teeth is negatively correlated with completed pulp therapy and extraction. SDF application prior to dental treatment with GA may be a valuable tool to reduce invasive dental procedures in GA.

Synergistic effects of arginine and fluoride on human dental biofilm control.

OBJECTIVES: The aim of this study was to quantitatively and comprehensively investigate the combined effects of arginine and fluoride on the suppression of pathogenicity using an in situ biofilm model and next-generation sequencing (NGS). METHODS: Using the in situ model, dental biofilms were formed and the viable bacterial counts and arginine activity in the arginine- and fluoride-containing dentifrice and control groups were measured. We also compared their effects on the bacterial microbiota and predictive functional factors in the control, arginine (arg), and arginine + fluoride (argF) groups using NGS analysis. RESULTS: Compared to the control treatment, the use of 8 % arginine and 1450 ppm fluoride toothpaste resulted in significantly high oral NH4+ concentrations without affecting the number of viable bacteria (P < 0.05). NGS analysis revealed that the oral microbiota of the control, arg, and argF groups were significantly different. Heat map analysis of the predicted functional factors revealed that the arg group had different properties from the other groups and activated specific substrate metabolic pathways; contrastingly, argF treatment inhibited the activity of these pathways and prevented an increase in the abundance of bacterial genera that utilize substrates such as sucrose, suggesting the synergistic effect of arginine and fluoride. CONCLUSIONS: This study indicates that the combination of arginine and fluoride has a synergistic effect on the bacterial microbiota and pathogenicity of dental biofilms compared with arginine alone. CLINICAL SIGNIFICANCE: Our findings suggest that the combination of arginine and fluoride could be used as an effective prebiotic and may inhibit the growth of bacteria associated with dental diseases.

A randomised clinical trial to arrest caries using silver diamine fluoride therapy with two postoperative instructions.

OBJECTIVE: The objective of this study is to investigate the beneficial effect of not rinsing for 30 min in arresting early childhood caries after SDF therapy. METHODS: This randomised clinical trial recruited 3- to 4-year-old kindergarten children with active (soft) dentine caries. A questionnaire was sent to the parents to collect children's demographic data and oral health-related behaviours. A dentist conducted an oral examination and measured the caries experience using dmft index and oral hygiene using visible plaque index. After 38 % SDF therapy, the children were randomly allocated into two groups. Children in group A were instructed to rinse with water immediately, whereas children in group B were asked to refrain from rinsing, drinking, or eating for 30 min. After six months, the same examiner determined the lesion activity (active/arrest) of the SDF-treated carious tooth surface. Generalized Estimating Equations was used to compare the proportion of caries arrest (caries-arrest rate) between the two groups. RESULTS: This study recruited 298 children with 1,158 decayed tooth surfaces receiving SDF therapy at baseline and evaluated 275 (92 %) children with 1,069 (92 %) SDF-treated tooth-surface at the six-month examination. The demographic background, oral hygiene and caries status of two groups were comparable at baseline (p > 0.05). The caries-arrest rate for group A and group B were 65 % (337/519) and 61 % (338/550), respectively (p = 0.28). CONCLUSION: This randomised clinical trial found not rinsing for 30 min after SDF therapy is not better than immediate rinsing in arresting early childhood caries. CLINICAL SIGNIFICANCE: Topical SDF application leaves an unpleasant taste in the mouth, which may affect the acceptance or even rejection of SDF therapy among young children. This study provides clinicians with information to make their decision on postoperative instruction after SDF therapy.

Preventing proximal enamel caries in neighboring tooth with glass ionomer cement restoration and silver diamine fluoride pretreatment.

OBJECTIVE: To investigate caries preventive effects of 38 % silver diamine fluoride (SDF) pretreatment on neighboring tooth proximal to glass ionomer cement (GIC), including conventional GIC (CGIC) and resin-modified GIC (RMGIC) restorations in an in vitro model. METHODS: HUMAN TOOTH BLOCKS WERE RESTORED WITH: SDF+CGIC (Group 1), CGIC (Group 2), SDF+RMGIC (Group 3) or RMGIC (Group 4). Enamel specimen simulating proximal surface of neighboring tooth was placed in proximity to the restorations. The specimen underwent cariogenic challenge with cross-kingdom biofilm of Streptococcus mutans, Lacticaseibacillus casei and Candida albicans. After cariogenic challenge, the biofilm's growth kinetics, viability, and morphology were evaluated by propidium monoazide-quantitative polymerase chain reaction (PMA-qPCR), confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM), respectively. The enamel lesion depth, surface morphology and crystal characteristics were determined by micro-computed tomography (micro-CT), SEM and X-ray diffraction (XRD), respectively. RESULTS: PMA-qPCR demonstrated lower microbial growth in Group 1 and 3 compared with Group 2 and 4 (p < 0.05). CLSM showed the dead-to-live ratio in Groups 1-4 were 1.15±0.12, 0.53±0.13, 1.10±0.24 and 0.63±0.10, respectively (Group 1,3 > 2,4, p < 0.05). SEM revealed Groups 1 and 3 had scattered biofilm whereas Group 2 and 4 had confluent biofilm. Micro-CT showed the enamel lesion depths (µm) were 98±9, 126±7, 103±6 and 128±7 for Group 1 to 4, respectively (Group 1,3 < 2,4, p < 0.05). SEM revealed oriented and ordered enamel prismatic patterns in Group 1 and 3, not in Group 2 and 4. XRD showed the reflections of hydroxyapatite in Groups 1 and 3 were sharper than Groups 2 and 4. CONCLUSION: SDF pretreatment enhances the preventive effect of GIC on proximal enamel surface on neighboring tooth through inhibiting cariogenic biofilm, reducing enamel demineralization and promoting enamel remineralization. CLINICAL SIGNIFICANCE: SDF pretreatment of GIC restorations can help prevent caries on neighboring teeth, particular for patients with high caries risk.

In vitro assessment of NaF/Chit supramolecular complex: Colloidal stability, antibacterial activity and enamel protection against S. mutans biofilm.

OBJECTIVES: This study assessed the effect of NaF/Chit suspensions on enamel and on S. mutans biofilm, simulating application of a mouthrinse. METHODS: The NaF/Chit particle suspensions were prepared at molar ratio [NaF]/Chitmon]≈0.68 at nominal concentrations of 0.2 % and 0.05 % NaF and characterized by Fourier transform infrared spectroscopy (FTIR), dynamic light scattering and zeta potential. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were measured. The S. mutans biofilm was formed for 7 days on eighty human enamel blocks that were divided into eight groups (n = 10/group): i) 0.05 % NaF solution; ii) 0.31 % Chit solution; iii) NaF/Chit(R=0.68) suspension at 0.05 % NaF; iv) 1.0 % HAc solution (Control); v) 0.2 % NaF solution; vi) 1.25 % Chit solution; vii) NaF/Chit(R=0.68) suspension at 0.2 % NaF; viii) 0.12 % chlorhexidine digluconate. The substances were applied daily for 90 s. S. mutans cell counts (CFU/mL) were performed, and the Knoop microhardness (KHN) of enamel samples were measured before and after biofilm formation. The KHN and CFU/mL data were analyzed by repeated measure ANOVA and Tukey's test (α = 0.05). RESULTS: Interactions between NaF and Chit were evidenced in solid state by FTIR spectra. The NaF/Chit complexes showed spontaneous microparticle formation and colloidal stability. The MIC and MBC ranged from 0.65 to 1.31 mg/mL. The NaF/Chit(R=0.68) suspension at 0.2 %NaF Group showed lower CFU/mL values than other groups. The NaF/Chit(R=0.68) suspensions Groups had the highest KHN values after biofilm formation. CONCLUSIONS: The NaF/Chit(R=0.68) complexes exhibited an antibacterial effect against S. mutans biofilm and reduced the enamel hardness loss. CLINICAL SIGNIFICANCE: The NaF/Chit(R=0.68) suspensions showed potential to be used as a mouthrinse for caries prevention.

Effects of graphene oxide and graphene quantum dots on enhancing CPP-ACP anti-caries ability of enamel lesion in a biofilm-challenged environment.

OBJECTIVE: To investigate the anticaries effects of graphene oxide (GO) and graphene quantum dots (GQDs) combined with casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) on enamel in a biofilm-challenged environment. MATERIAL AND METHODS: GO and GQDs were synthesised using citric acid. The antibiofilm and biofilm inhibition effects for Streptococcus mutans were evaluated by scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM), and colony-forming units (CFU). Remineralisation ability was determined by assessing mineral loss, calcium-to-phosphorus ratio, and surface morphology. To create a biofilm-challenged environment, enamel blocks were immersed in S. mutans to create the lesion and then subjected to artificial saliva/biofilm cycling for 7 days. Anticaries effects of GO, GQDs, GQDs@CPP-ACP, GO@CPP-ACP, and CPP-ACP were determined by broth pH and mineral changes after 7-day pH cycling. Biocompatibility was tested using a Cell Counting Kit-8 (CCK8) assay for human gingival fibroblasts (HGF-1). RESULTS: GQDs and GO presented significant antibiofilm and biofilm inhibition effects compared to the CPP-ACP and control groups (P < 0.05). The enamel covered by GQDs and GO showed better crystal structure formation and less mineral loss (P < 0.05) than that covered by CPP-ACP alone. After 7 days in the biofilm-challenged environment, the GO@CPP-ACP group showed less lesion depth than the CPP-ACP and control groups (P < 0.05). GO and GQDs showed good biocompatibility compared to the control group by CCK8 (P > 0.05) within 3 days. CONCLUSION: GO and GQDs could improve the anti-caries effects of CPP-ACP, and CPP-ACP agents with GO or GQDs could be a potential option for enamel lesion management. CLINICAL SIGNIFICANCE: GO and GQDs have demonstrated the potential to significantly enhance the anticaries effects of CPP-ACP. Incorporating these nanomaterials into CPP-ACP formulations could provide innovative and effective options for the management of enamel lesions, offering improved preventive and therapeutic strategies in dental care.