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Divalent cations have captured the interest of researchers in biomedical and dental fields due to their beneficial effects on bone formation. These metallic elements are similar to trace elements found in human bone. Strontium is a divalent cation commonly found in various biomaterials. Since strontium has a radius similar to calcium, it has been used to replace calcium in many calcium-containing biomaterials. Strontium has the ability to inhibit bone resorption and increase bone deposition, making it useful in the treatment of osteoporosis. Strontium has also been used as a radiopacifier in dentistry and has been incorporated into a variety of dental materials to improve their radiopacity. Furthermore, strontium has been shown to improve the antimicrobial and mechanical properties of dental materials, promote enamel remineralization, alleviate dentin hypersensitivity, and enhance dentin regeneration. The objective of this review is to provide a comprehensive review of the applications of strontium in dentistry.

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OBJECTIVE: This systematic review aimed to describe and evaluate the caries patterns among the 21st century preschool children globally. METHOD: Six electronic databases (Pubmed, Embase, Medline, Web of Science, EBSCOhost, and Scopus) were searched using predetermined terms. Dual independent screening of all retrieved abstracts was performed to identify studies conducted after year 2000 and the caries pattern among preschool children was investigated. Data regarding the prevalence of caries by tooth type and surface were extracted. Meta-analyses, subgroup analyses and meta-regression were carried out with the statistics software Stata using the random-effects model. RESULTS: A total of 2642 records were screened, and 43 observational studies were finally included. Cavitated caries lesions were commonly found in the maxillary incisors and molars in both arches among preschool children. The highest caries prevalence was found in the maxillary central incisors (29.1%, 95%CI: 25.5%-32.7%) and the mandibular second molars (28.5%, 95%CI: 24.7%-32.3%), while the mandibular lateral incisors had the lowest prevalence (1.7%, 95%CI: 1.5%-2.0%). Occlusal surfaces of the mandibular molars were the most frequently affected by caries, whereas caries hardly affected the lingual surfaces of lower anterior teeth. Caries pattern on the left and right sides was symmetrical. The overall caries prevalence was significantly higher in the maxillary teeth. Caries prevalence was higher in the older children, whereas the caries pattern was not significantly different among children from countries with different human and economic development levels. CONCLUSION: Cavitated carious lesions were more commonly observed in the maxillary incisors and molars in both arches. The prevalence of caries varies significantly with child's age and primary tooth type. However, preschool children exhibit a similar pattern of caries, regardless of the time, socioeconomic status or geographical location.

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AIM: Lack of adequate mechanical strength and progressive shrinkage over time remain challenges in scaffold-free microtissue-based dental pulp regeneration. Surface collagen cross-linking holds the promise to enhance the mechanical stability of microtissue constructs and trigger biological regulations. In this study, we proposed a novel strategy for surface preconditioning microtissues using a natural collagen cross-linker, proanthocyanidin (PA). We evaluated its effects on cell viability, tissue integrity, and biomineralization of dental pulp stem cell (DPSCs)-derived 3D cell spheroids. METHODOLOGY: Microtissue and macrotissue spheroids were fabricated from DPSCs and incubated with PA solution for surface collagen cross-linking. Microtissue viability was examined by live/dead staining and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, with transverse dimension change monitored. Microtissue surface stiffness was measured by an atomic force microscope (AFM). PA-preconditioned microtissues and macrotissues were cultured under basal or osteogenic conditions. Immunofluorescence staining of PA-preconditioned microtissues was performed to detect dentin sialophosphoprotein (DSPP) and F-actin expressions. PA-preconditioned macrotissues were subjected to histological analysis, including haematoxylin-eosin (HE), alizarin red, and Masson trichrome staining. Immunohistochemistry staining was used to detect alkaline phosphatase (ALP) and dentin matrix acidic phosphoprotein 1 (DMP-1) expressions. RESULTS: PA preconditioning had no adverse effects on microtissue spheroid viability and increased surface stiffness. It reduced dimensional shrinkage for over 7 days in microtissues and induced a larger transverse-section area in the macrotissue. PA preconditioning enhanced collagen formation, mineralized nodule formation, and elevated ALP and DMP-1 expressions in macrotissues. Additionally, PA preconditioning induced higher F-actin and DSPP expression in microtissues, while inhibition of F-actin activity by cytochalasin B attenuated PA-induced dimensional change and DSPP upregulation. CONCLUSION: PA surface preconditioning of DPSCs spheroids demonstrates excellent biocompatibility while effectively enhancing tissue structure stability and promoting biomineralization. This strategy strengthens tissue integrity in DPSC-derived spheroids and amplifies osteogenic differentiation potential, advancing scaffold-free tissue engineering applications in regenerative dentistry.

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OBJECTIVES: This study developed a sol-gel tricalcium silicate/graphene oxide (TCS-GO) composite and examined its physicochemical properties, antimicrobial activity, and osteo/odontogenic effect on dental pulp stem cells. METHODS: Tricalcium silicate was synthesized and combined with graphene oxide at three different concentrations, namely 0.02%, 0.04%, and 0.08% w/w, while tricalcium silicate and mineral trioxide aggregate served as controls. The setting time, compressive strength, pH, and calcium ion release of the composites were evaluated, as well as antimicrobial properties against Streptococcus mutans and Lactobacillus acidophilus. Additionally, the viability of dental pulp stem cells; apatite forming ability; and the gene expression of Alkaline phosphatase, Dentin sialophosphoprotein, and Runt-related transcription factor 2 were assessed. RESULTS: TCS-GO (0.08%) showed a significantly shorter setting time and higher compressive strength when compared to MTA (p < 0.05). Additionally, tricalcium silicate and TCS-GO groups showed a higher release of Ca ions than MTA, with no significant difference in pH values among the different groups. TCS-GO (0.08%) also demonstrated a significantly stronger antimicrobial effect against Lactobacillus acidophilus compared to MTA (p < 0.05). ALP expression was higher in TCS-GO (0.08%) than MTA on days 3 and 7, while DSPP expression was higher in TCS-GO (0.08%) than MTA on day 3 but reversed on day 7. There was no significant difference in RUNX2 expression between TCS-GO (0.08%) and MTA on days 3 and 7. CONCLUSIONS: The TCS-GO (0.08%) composite demonstrated superior physicochemical characteristics and antimicrobial properties compared to MTA. Moreover, the early upregulation of ALP and DSPP markers in TCS-GO (0.08%) indicates that it has the potential to promote and enhance the osteo/odontogenic differentiation of DPSCs.

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OBJECTIVE: To evaluate the effect of ions released from surface pre-reacted glass-ionomer (S-PRG) filler on collagen morphology, remineralization, and ultimate tensile strength (UTS) of demineralized dentin. MATERIALS AND METHODS: Bovine incisor root dentins were demineralized with EDTA and divided into three treatment groups: 1) water (control); 2) S-PRG filler eluate; 3) 125 ppm sodium fluoride (NaF). After a 3-min treatment, the specimens were stored in simulated body fluid (SBF) for 3 months. Collagen morphology and remineralization were assessed using transmission electron microscopy (TEM), scanning electron microscopy (SEM), and Fourier-transform infrared spectroscopy (FTIR). Additionally, ultimate tensile strength (UTS) was measured. RESULTS: TEM and SEM demonstrated that S-PRG induced more effective remineralization compared to NaF, while the control group exhibited faint mineral deposition with collagen degradation. S-PRG displayed the most homogenous mineral deposition in collagen fibrils, along with closure of interfibrillar spaces. Extensive mineral precipitation was observed within dentinal tubules in the S-PRG group. In addition, S-PRG filler eluate demonstrated significantly higher phosphate-to-amide ratio and UTS compared to NaF and control groups (p < 0.05). CONCLUSIONS: Ion released from S-PRG filler positively influenced collagen morphology, remineralization, and ultimate tensile strength of demineralized dentin. CLINICAL SIGNIFICANCE: S-PRG filler enhances remineralization and improve the biomechanics of demineralized dentin.

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OBJECTIVES: To investigate enamel remineralization and antimicrobial effect of sodium fluoride (NaF) varnish containing calcium strontium silicate (CSR). METHODS: CSR was synthesized by sol-gel process and incorporated in 5 % NaF varnish at three different concentrations (1 %, 2 %, and 4 % w/v). The treatment/control groups were: 1 % CSR+NaF, 2 % CSR+NaF, 4 % CSR+NaF, NaF, and no treatment. Strontium and fluoride release from the varnishes was evaluated. Sound enamel specimens (n = 6) were demineralized, varnish-treated, and subjected to remineralization cycle. Mineral density of enamel specimens was evaluated using micro-CT. Antimicrobial effect of the varnishes on Streptococcus mutans and Lactobacillus acidophilus biofilms was assessed using confocal laser scanning microscopy. The HGF-1 cytotoxicity of the varnishes was examined using CCK-8 assay. RESULTS: Both 2 % and 4 % CSR+NaF varnishes showed significantly higher F release and remineralization potential than NaF varnish (p < 0.05). Dead bacterial proportion of 4 % CSR+NaF varnish was significantly higher than NaF varnish (p < 0.05). The CFUs values of both S. mutans and L. acidophilus were significantly lower in 4 % CSR+NaF group than NaF group (p < 0.05). No significant difference in cell viability was observed among the groups (p > 0.05). CONCLUSIONS: Incorporation of 4 % CSR in a NaF varnish significantly enhanced its enamel remineralization and antimicrobial potential with no cytotoxic effect. CLINICAL SIGNIFICANCE: Dental caries is a major public health problem globally. The study highlights the great potential of CSR-doped NaF varnish as a novel anti-caries agent with synergistic remineralizing and antimicrobial properties to combat early enamel caries lesions in the general population.

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This review aimed to systematically investigate the effect of minimal intervention dentistry on patient-reported and observation-based outcomes of anxiety, pain and patient cooperation in the pediatric population. Microinvasive treatments (MITs) were compared to conventional treatments, home-based and professionally applied non-invasive treatments (NITs), and between MITs. Two reviewers independently screened studies from four electronic databases, extracted data, assessed the risk of bias and certainty of evidence with the GRADE approach. Ultimately, 26 studies were included for qualitative synthesis, with the data from 12 studies being incorporated into the meta-analysis. No statistically significantly differences in terms of anxiety were noted between MITs and conventional treatments, or between MITs from the meta-analyses. The treatment durations of MITs were not necessarily shorter than conventional treatments but varied with the use of local anesthesia, behavioral and clinical approach, and other confounding factors. The certainties of evidence were deemed low due to high risk of bias of the included studies. NITs evoked less anxiety and pain compared to MITs. Minimal intervention dentistry is an alternative treatment to manage dental caries among children and does not arouse different levels of dental anxiety and pain compared to other treatment modalities. However, further well-designed studies are required to draw an evidence-based conclusion.

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OBJECTIVE: The aim of this study was to evaluate the risk indicators associated with noncavitated and cavitated lesions in preschool children. METHODS: The cross-sectional study included 3- to 4-year-old healthy children (N = 741) recruited in a randomised controlled clinical trial. After obtaining written informed consent, parents completed a questionnaire about their child's sociodemographic background and oral health-related behaviours and parents' oral health-related knowledge and attitude. Caries and plaque were evaluated using International Caries Detection and Assessment System-II and Visible Plaque Index (VPI), respectively. Children were grouped according to their oral health status as being caries-free (CF), having only noncavitated lesions (NC), or having cavitated lesions (CL). The least absolute shrinkage and selection operator (LASSO) sparse multinomial regression was used to study the variables using 1 standard error above the minimum criterion set at P < .05. RESULTS: The prevalence of children with NC and CL was 29.1% and 49.4%, respectively, with a prevalence of early childhood caries being 78.5%. The proportion of children who brushed twice or more than twice a day was highest in CF (71.7%), followed by NC (58.3%), and was least in CL (57.7%). A higher percentage of CL children (56.2%) had twice or more than twice the frequency of between-meal snacking than CF (41.7%) and NC (41.1%) (P < .001) children. The variables included with non-zero coefficients in the model were mean parental oral health knowledge, attitude score, and children's mean VPI score, and all were significant for CL; however, in NC, only VPI score was found to be significant. CONCLUSIONS: Poor oral hygiene is the risk indicator associated with the presence of NC in preschool children, whilst poor oral hygiene and poor parental oral health knowledge and attitude are associated with the presence of cavitated lesions.

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OBJECTIVES: The study objective was to examine the effect of synbiotic-fluoride (SF) therapy within a multi-species cariogenic biofilm model system comprising of S. mutans, S. sanguinis, and S. gordonii. METHODS: The SF therapy was prepared using 2% L-arginine (Arg), 0.2% NaF and probiotic L. rhamnosus GG (LRG). The 8 treatment groups were: Group 1: No treatment, Group 2: 2% Arg, Group 3: 0.2% NaF, Group 4: LRG, Group 5: 2% Arg+0.2% NaF, Group 6: 2% Arg+LRG, Group 7: 0.2% NaF+LRG, and Group 8: SF therapy (2% Arg+0.2% NaF +LRG). Multi-species biofilm model over 96 h comprising Streptococcus mutans, Streptococcus sanguinis, and Streptococcus gordonii was utilized. The biofilms received cariogenic challenge and SF therapy 2 × /day. The extracellular matrix components were analyzed for carbohydrates, proteins, and extra-cellular DNA (eDNA). The live/dead cells were imaged and quantified using confocal microscopy. The viable/dead bacterial concentrations were estimated using propidium monoazide-quantitative polymerase chain reaction (PMA-qPCR). The gene expressions for gtfB, sagP, arcA, argG, and argH were measured using real-time reverse transcriptase qPCR. RESULTS: Carbohydrates and protein content with SF therapy were higher than non-LRG containing groups, while eDNA content was lower than other groups (p<0.05). Live bacterial proportions determined using confocal imaging with SF therapy were the lowest (p<0.05). The 2% Arg+LRG and SF therapy showed higher viable L. rhamnosus GG than 0.2% NaF+LRG (p<0.05). The dead S. mutans with SF therapy were higher than the other groups (p<0.05) with no difference from 2% Arg+0.2% NaF and 2% Arg+LRG (p>0.05). The SF therapy significantly downregulates gtfB and upregulates sagP, arcA, argG, argH gene expression (p<0.05). CONCLUSION: Synbiotic-fluoride therapy effectuates multi-fold changes in the multi-species biofilm matrix and cellular components leading to superior ecological homeostasis than its individual contents, prebiotics (arginine), probiotic (L. rhamnosus GG), and fluorides (NaF). CLINICAL SIGNIFICANCE: The ecological-based synbiotic-fluoride caries-preventive therapy aids in maintaining biofilm homeostasis to preempt/restore dysbiosis thereby sustaining dynamic-diverse health-associated microbial stability significant as a preventive regimen for high caries-risk patients.

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OBJECTIVE(S): The objectives of the present study were to examine the - a) enamel remineralization potential of synbiotic-fluoride (SF) therapy using a multi-species bacterial pH-cycling model; and b) cytotoxic and genotoxic effects of SF therapy extracts. MATERIALS AND METHODS: The SF therapy group comprised of 2% arginine (Arg), 0.2% NaF, and a probiotic Lactobacillus rhamnosus GG (LRG). The intervention groups studied were: 1) No treatment; 2) 2% Arg; 3) 0.2% NaF; 4) LRG; 5) 2% Arg+0.2% NaF; 6) 2% Arg+LRG; 7) 0.2% NaF+LRG; and 8) 2% Arg+0.2% NaF+LRG (SF therapy). The enamel remineralization potential of SF therapy was investigated under cariogenic biofilm challenge; while the cytotoxicity and genotoxicity of SF therapy extracts were examined on HGF-1 and Chinese hamster fibroblast V79, respectively. To determine the remineralization effect, the specimens were subjected to mineral density (MD) assessment using micro-CT, Ca/P molar ratio with SEM-EDX, and enamel fluoride uptake (EFU) estimates. The HGF-1 proliferation assessment was quantified using MTT/CCK-8 assays with qualitative analysis by nuclei staining Hoechst-based fluorescence imaging. The genotoxicity was determined by micronuclei formation test. RESULTS: Mineral gain and %remineralization derived from MD assessment for the SF therapy were significantly higher than the other groups (p<0.05). The %ΔCa/P for the SF and 2% Arg+0.2% NaF were significantly higher than the other groups (p<0.05). The SF and 2% Arg+0.2% NaF groups had the highest EFU compared to the other groups (p<0.05). No significant difference in the %viable HGF-1 cells were observed between the treatment interventions and no treatment group (p>0.05). Compared to the EMS-positive control, the micronuclei formation for all the intervention groups was significantly lower (p<0.05), with no significant difference among the treatment groups (p>0.05). CONCLUSION: The SF therapy enhanced enamel remineralization with no biocompatibility concerns. CLINICAL SIGNIFICANCE: With the enhanced enamel remineralization potential discerned in the present study, the SF therapy can be used as a promising caries-preventive agent targeted for high caries-risk individuals.

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BACKGROUND: Due to some unique physical, social and psychological features in the adolescent population, adolescents can be a time of heightened caries activity and periodontal disease. Oral health-related behaviors can be modified to improve oral health status. The family networks and the built environment can promote or inhibit health behaviors. The aim of this study is to implement and evaluate a behavior theory-based, integrated family intervention via mobile messaging to improve oral health of adolescents. METHODS: This is a three-arm parallel-design cluster-randomized controlled trial. This trial will allocate 12 local secondary schools (clusters) in Hong Kong to three test or comparison groups with a ratio 1:1:1. The enrolled Form II to IV students (ages 12 to 15) will be eligible for participation. The intervention to three study groups will be (i) Health Belief Model (HBM)-based mobile messaging to the adolescents and their parents, which will consist of several blocks of HBM-based messages and reinforcement during 24 weeks; (ii) same HBM-based messaging to adolescents only; and (iii) delivering e-version of oral health education pamphlets to adolescents. The primary outcome will be caries increment 2 years post-intervention. Changes in oral health self-efficacy and behaviors, oral hygiene, and gingival status will be the secondary outcomes. DISCUSSION: No school dental care service is available to secondary school students in Hong Kong. This study will be the first to test a theory-driven and family-engaged preventive intervention among adolescents in Hong Kong. Findings will contribute to developing a low-cost, feasible, and efficient oral health preventive program for adolescents. TRIAL REGISTRATION: ClinicalTrials.gov NCT05448664 . Registered on 7 July 2022.

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The aim of this paper is to systematically review the literature to determine whether early childhood caries (ECC) is significantly associated with caries development in permanent teeth among school children and adolescents, and to identify the association of other risk factors over 24 months. A systematic literature search was performed in four electronic databases and via a manual search from inception to 28 July 2022. Independent study selection and screening, data extraction, evaluation of risk of bias using ROBINS-I tool and certainty of evidence with GRADE were performed. Ten cohort studies were included, all of which identified that ECC significantly increased the risk of caries in permanent teeth. Meta-analysis suggested children with ECC were three times more likely to develop caries in their permanent teeth (OR, 3.22; 95% CI 2.80, 3.71; p < 0.001), especially when the lesions were in primary molars and progressed to dentine. However, the certainty of evidence was substantially compromised by serious risk of bias and inconsistency between studies. There were inconsistent findings between socioeconomic or behavioural factors on caries development, which could not be pooled for meta-analyses. ECC significantly increases the likelihood of caries development in permanent teeth. Evidence on the association of socioeconomic and oral health behavioural factors is weak.

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Oral health is an integral component of general health and well-being but might be undermined among children living with HIV (CLWH) due to the condition itself or the antiretroviral therapy (ART) received. This review summarises the current evidence and compares the oral health status of the CLWH who were treatment-naïve with those undergoing different ART medications. Fourteen studies were included in the final qualitative and quantitative analyses. This review identified no significant difference in the prevalence of caries, periodontal conditions, and tooth development between both groups. Orofacial opportunistic infections were more prevalent in the CLWH without ART. Children undergoing ART with a duration longer than 3 years had a significantly lower prevalence of oral candidiasis and CD4+ T-cell counts. However, due to the insufficient number of well-administered case-control studies with adequate sample size, the quality of the evidence in all outcomes was of very low certainty.

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Antiretroviral therapy (ART) increases the survival of HIV-infected children, but might also bring in oral health-related side effects and increase their risks of oral diseases. The review compared the oral health status of children living with HIV (CLWH) undergoing ART with healthy controls. Dual independent screening and study selection from four electronic databases and manual searches, data extraction, risk of bias assessment, and quality-of-evidence evaluation with Grading of Recommendations Assessment Development and Evaluation were performed. Twelve studies were included in qualitative and quantitative analysis. CLWH taking ART had a significantly higher prevalence of periodontal diseases (OR = 3.11, 95% CI 1.62-5.97), mucosal hyperpigmentation (OR = 20.35, 95% CI 3.86-107.39), and orofacial-related opportunistic infections than healthy controls. No significant differences regarding caries prevalence and tooth development were identified. Those with CD4+ T-cell counts below 250 cells/mm3 were more likely to manifest opportunistic infections, while medication duration had minimal influence on the prevalence of orofacial opportunistic infections. The current findings did not identify HIV and antiretroviral status as predisposing factors to dental caries, but affirmed the associated increased risk of periodontal diseases, mucosal hyperpigmentation and candidiasis.

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The development of biomaterials that exhibit profound bioactivity and stimulate stem cell differentiation is imperative for the success and prognosis of vital pulp therapies. The objectives were to (1) synthesize calcium strontium silicate (CSR) ceramic through the sol−gel process (2) investigate its physicochemical properties, bioactivity, cytocompatibility, and its stimulatory effect on the differentiation of human dental pulp stem cells (HDPSC). Calcium silicate (CS) and calcium strontium silicate (CSR) were synthesized by the sol−gel method and characterized by x-ray diffraction (XRD). Setting time, compressive strength, and pH were measured. The in vitro apatite formation was evaluated by SEM-EDX and FTIR. The NIH/3T3 cell viability was assessed using an MTT assay. The differentiation of HDPSC was evaluated using alkaline phosphatase activity (ALP), and Alizarin red staining (ARS). Ion release of Ca, Sr, and Si was measured using inductive coupled plasma optical emission spectroscopy (ICP-OES). XRD showed the synthesis of (CaSrSiO4). The initial and final setting times were significantly shorter in CSR (5 ± 0.75 min, 29 ± 1.9 min) than in CS (8 ± 0.77 min, 31 ± 1.39 min), respectively (p < 0.05). No significant difference in compressive strength was found between CS and CSR (p > 0.05). CSR demonstrated higher apatite formation and cell viability than CS. The ALP activity was significantly higher in CSR 1.16 ± 0.12 than CS 0.92 ± 0.15 after 14 d of culture (p < 0.05). ARS showed higher mineralization in CSR than CS after 14 and 21 d culture times. CSR revealed enhanced differentiation of HDPSC, physicochemical properties, and bioactivity compared to CS.

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OBJECTIVES: To evaluate the inhibitory effect of a novel mussel-inspired monomer (N-(3,4-dihydroxyphenethyl)methacrylamide (DMA) on the soluble and matrix-bound proteases. METHODS: The inhibitory effect of DMA (0, 1, 5, and 10 mM) and 1 mM chlorhexidine (CHX) dissolved in 50% ethanol/water on soluble recombinant human matrix metalloproteinases (rhMMP-2, -8, and -9), as well as cysteine cathepsins (B and K) were evaluated using both fluorometric assay kits and molecular docking. The effect of CHX and DMA on matrix-bound proteases was examined by in situ zymography, and the fluorescence intensity and relative area were calculated by Image J software. All data obtained were analyzed by one-way ANOVA followed by Tukey test (α = 0.05). RESULTS: The anti-proteolytic ability of DMA increased in a dose-dependent manner except that of rhMMP-9. Inhibitory effect of 1 mM DMA against rhMMP-2, - 8, - 9, as well as cathepsin B and K was all significantly lower than 1 mM CHX (p < 0.05). The molecular docking analysis was in good agreement with the experimental results, that the binding energy of DMA was lower than CHX for all proteases. In situ zymography revealed that all DMA- and CHX-treated groups significantly inactivated the matrix-bound proteases, with a dramatic reduction of the fluorescence intensity and relative area compared with the control group (p < 0.05). SIGNIFICANCE: Under the prerequisite condition that the overall inhibitory performance on matrix-bound proteases was comparable by DMA and CHX, the more selective property of DMA could avoid inducing potential negative effects by suppressing MMP-9 when applied in dental treatment compared with CHX.

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OBJECTIVES: To examine the biofilm modulatory effect of arginine (Arg)-fluoride (F) varnish on multi-species biofilms. METHODS: Experimental varnishes were prepared by incorporating L-Arg (1, 2, and 4%) in 5% NaF varnish, which served as the control. Multi-species biofilms comprising Streptococcus mutans, Streptococcus sanguinis and Streptococcus gordonii were grown on hydroxyapatite (HA) discs and treated with the Arg and F released from the experimental and control groups. The HA discs with treated biofilms were examined for biofilm composition. The biofilm thickness and live/dead counts were investigated using confocal microscopic imaging, while biofilm polysaccharides, proteins, and extracellular DNA (eDNA) were assessed spectrophotometrically. Bacterial composition in biofilms was analysed using viability real-time quantitative polymerase chain reaction (qPCR). The relative gene expression (RGE) was determined for gtfB, SMU.150, nlmD, arcA, and sagP. RESULTS: Both the 2 and 4% Arg-NaF groups reduced biofilm thickness, with the 4% Arg-NaF group showing a significantly greater proportion of dead bacteria, followed by 1 and 2% Arg-NaF (p < 0.001). All Arg-NaF groups significantly reduced the carbohydrate content of the biofilm, while the 4% Arg-NaF-treated biofilms demonstrated higher concentration of eDNA and proteins compared to the control NaF (p < 0.001). Expression of gtfB, SMU.150, and nlmD were significantly downregulated in 4% Arg-NaF-treated biofilms; while 2% Arg-NaF enhanced the expression of arcA. Both 2% Arg-NaF and 4% Arg-NaF significantly increased the expression of sagP. CONCLUSION: The incorporation of L-arginine (2%/4%) enhances the biofilm modulatory effect of 5% NaF varnish through released Arg and F. CLINICAL SIGNIFICANCE: The study results indicate that Arg-F varnish (at 2%/4% w/v. Arg) has the potential to modulate cariogenic biofilms in high-risk individuals.

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The prevalence of dental erosion among preschool children and its associated factors range widely between studies. The aims of this review are to evaluate the literature and to determine the prevalence and associated factors of dental erosion among children below 7 years old. An electronic search was undertaken to identify observational studies evaluating the prevalence of dental erosion and its associated factors in children below 7 years old. Dual independent screening, data extraction, risk of bias assessment, meta-analysis, meta-regression, and evaluation of quality of evidence were performed. Twenty-two papers were included. The overall estimated prevalence of dental erosion in children was 39.64% (95% CI: 27.62, 51.65; I2 = 99.9%), with very low certainty of evidence. There was also low-quality evidence suggesting that the likelihood of (1) boys having dental erosion was significantly higher than girls (p < 0.001) and (2) children with digestive disorders having dental erosion was significantly higher than those without such digestive disorders (p = 0.002). Qualitative synthesis identified that more frequent intake of fruit juices and soft drinks correlated with erosive tooth wear. Dental erosion is prevalent among over one-third of preschool children. Digestive disorders and dietary factors are the main potential contributing factors.

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Various materials are used in bone tissue engineering (BTE). Graphene oxide (GO) is a good candidate for BTE due to its antibacterial activity and biocompatibility. In this study, an innovative biomaterial consists of GO, agarose and hydroxyapatite (HA) was synthesized using electrophoresis system. The characterization of the synthesized biomaterial showed that needle-like crystals with high purity were formed after 10 mA/10 h of electrophoresis treatment. Furthermore, the calcium-phosphate ratio was similar to thermodynamically stable HA. In the synthesized biomaterial with addition of 1.0 wt% of GO, the colony forming units test showed significantly less Staphylococcus aureus. Initial attachment of MC3T3-E1 cells on the synthesized biomaterial was observed which showed the safety of the synthesized biomaterial for cell viability. This study showed that the synthesized biomaterial is a promising material that can be used in BTE.

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The study objective was to examine the acid-resistance potential of enamel carious lesions treated with arginine (Arg)-sodium fluoride (NaF) varnishes using nano-mechanical testing and chemical mapping. L-arginine (at 1%, 2%, & 4%) was incorporated in 5% NaF varnish. The experimental/control groups were: 1% Arg-NaF, 2% Arg-NaF, 4% Arg-NaF, NaF, and no treatment. Enamel specimen blocks were subjected to incipient carious lesion formation. After treatment, the specimens underwent chemical pH-cycling for 8-days and acid challenge for 2 h. The specimens were characterised for surface nano-hardness (SNH) and calcium/phosphate content of the treated lesions to determine enamel solubility reduction (ESR). Post-acid challenge, X-ray diffraction crystallography (XRD), and energy dispersive X-ray spectrophotometry (EDX) were performed. The SNH for 2%/4% Arg-NaF demonstrated a higher resistance to acid challenge with significantly higher SNH recovery than NaF varnish (p<0.05). The ESR potential of 2%/4% Arg-NaF varnish was significantly higher than NaF varnish (p<0.05). The XRD crystalline phases demonstrated that 2%/4% Arg-NaF had intense hydroxyapatite peaks discerning its increased potential to resist demineralization than NaF varnish. The EDX results showed that 2%/4% Arg-NaF demonstrated Ca/P ratio closer to hydroxyapatite (~1.67) post-acid challenge. Incorporating 2%/4% L-arginine in a 5% NaF varnish enhances the acid-resistance potential of NaF varnish.

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