Dental caries

Antibacterial and antibiofilm activities of extract and bioactive compounds from Bergenia ciliata (Haw.) Sternb. flowers against Streptococcus mutans through cell membrane damage

ETHNOPHARMACOLOGICAL RELEVANCE

Bergenia ciliata (Haw.) Sternb. (Family Saxifragaceae) remains mentioned as Pashanbheda in Ayurveda and Zakhmehayat in Unani. In North Waziristan, Pakistan, indigenous communities use this plant in ethnodentistry to treat tooth decay and toothaches. However, scientific evidence on its mode of action is still lacking.

AIM OF THE STUDY

To evaluate the effect of extracts and fractions of B. ciliata flower against oral bacteria and elucidate the possible antibacterial and antibiofilm mechanism.

MATERIALS AND METHODS

Prepared extract of B. ciliata flowers were checked for its antibacterial activity against oral (S. mutans, S. pyogenes, S. oralis) and opportunistic bacteria (Staphylococcus aureus, Citrobacter clonae and Achromobacter insolitus). Preparative TLC-bioautography and silica gel column chromatography was used to isolate bioactive compounds. HRESI-MS and NMR studies were employed for its structural elucidation. Antibacterial and antibiofilm activities of extracts and isolated compounds were studied against S. mutans. Scanning Electron Microscope studies indicated membrane damage. Reactive Oxygen Species (ROS) production, lipid peroxidation and cytoplasmic leakage were also assessed.

RESULTS

The most active ethyl acetate extract (EA) showed potent inhibitory effect against S. mutans (0.390 μg/μl). TLC-bioautography indicated spots F1 & F2 to show inhibition zones. F1 was identified as kaempferol. This is the first report on flowers of B. ciliata against oral infection. The mode of action of F1 can be attributed to its ability to destroy the membrane integrity, reducing and disrupting biofilm. It also produced ROS within the bacterial cell, leading to lipid peroxidation and subsequently causing death of the bacteria.

CONCLUSION

Kaempferol is the active compound in bioactive spot F1 which showed antibacterial and antibiofilm activity. The antibacterial activity can be linked with the membrane disrupting properties of kaempferol and producing ROS inside S. mutans. Thus, phytochemicals derived from B. ciliata can be used in the development of pharmaceutical dental products.

Cordycepin affects Streptococcus mutans biofilm and interferes with its metabolism

BACKGROUND

Streptococcus mutans (S. mutans) contributes to caries. The biofilm formed by S. mutans exhibits greater resistance to drugs and host immune defenses than the planktonic form of the bacteria. The objective of this study was to evaluate the anti-biofilm effect of cordycepin from the perspective of metabolomics.

METHODS

The minimum inhibitory concentration (MIC) was determined to evaluate the antimicrobial effect of cordycepin on planktonic S. mutans. The 24-h biofilm was treated with 128 µg/mL of cordycepin for 10 min at the 8- or 20-h time points. Biofilm biomass and metabolism were assessed using crystal violet and MTT assays and cordycepin cytotoxicity was evaluated in human oral keratinocytes (HOK) using CCK-8 assays. The live bacterial rate and the biofilm volume were assessed by confocal laser scanning microscopy. Metabolic changes in the biofilm collected at different times during with cordycepin were analyzed by metabolomics and verified by quantitative real-time PCR.

RESULTS

The results showed that treatment with 128 µg/mL cordycepin reduced both the biomass and metabolic activity of the biofilm without killing the bacteria, and cordycepin at this concentration showed good biocompatibility. Metabolomics analysis showed that differentially abundant metabolites following cordycepin treatment were mainly related to purine and nucleotide metabolism. After immediate treatment with cordycepin, genes related to purine and nucleotide metabolism were downregulated, and the levels of various metabolites changed significantly. However, the effect was reversible. After continuing culture for 4 h, the changes in genes and most metabolites were reversed, although the levels of 2'-deoxyadenosine, 2'-deoxyinosine, and adenine remained significantly different.

CONCLUSIONS

Cordycepin has the effect of anti-biofilm of S. mutans, mainly related to purine and nucleotide metabolism.

Do progression rates of initial and moderate caries lesions and sound surfaces of primary teeth increase significantly after 7 years?

BACKGROUND

Initial caries lesions in primary teeth have presented a low progression rate after 2 years, but it could be higher in longer follow-ups.

AIM

To evaluate the progression rates of sound surfaces and initial and moderate caries lesions after 7 years.

DESIGN

This prospective 7-year cohort study included 639 preschool children aged 1-5 years in 2010. In 2017, 449 children were reassessed (70.3% retention rate). Dental caries was collected using the International Caries Detection and Assessment System (ICDAS) in both assessments. Incidence rate (IR) per 100 surface-years estimated the progression rates of sound surfaces and initial and moderate lesions for worse conditions. Cox regression with shared frailty evaluated the possible risk factors.

RESULTS

IR was 1.0% for sound surfaces, 2.8% and 4.2% for ICDAS scores 1 and 2, respectively, and about 17.0% for moderate lesions. The most significant risk factor for the progression was the presence of cavitated lesions in other teeth. The type of surface and tooth also influenced the outcome.

CONCLUSION

The progression rate of initial caries lesions in primary teeth remains low even after 7 years, but cavitated caries lesions in other teeth increase this risk. Moderate lesions demonstrate a higher risk of progression when compared to sound surfaces and initial caries lesions.

Wearable Multifunctional Hydrogel for Oral Microenvironment Visualized Sensing Coupled with Sonodynamic Bacterial Elimination and Tooth Whitening

Bacterial-driven dental caries and tooth discoloration are growing concerns as the most common oral health problems. Current diagnostic methods and treatment strategies hardly allow simultaneous early detection and non-invasive treatment of these oral diseases. Herein, a wearable multifunctional double network hydrogel combined with polyaniline and barium titanate (PANI@BTO) nanoparticles is developed for oral microenvironment visualized sensing and sonodynamic therapy. Due to the colorimetric properties of polyaniline, the hydrogel displays a highly sensitive and selective response for visualized sensing of oral acidic microenvironment. Meanwhile, the barium titanate in the hydrogel efficiently generates reactive oxygen species (ROS) under ultrasound irradiation, realizing non-invasive treatment in the oral cavity. Through bacterial elimination experiments and tooth whitening studies, the hydrogel can achieve the dual effect of effectively inhibiting the growth of cariogenic bacteria and degrading tooth surface pigments. Owing to the visualized sensing of the oral acidic microenvironment and efficient sonodynamic therapy function, the proposed hydrogel system offers a solution for the prevention of caries and tooth whitening, which is promising in developing the biomedical system targeting the simultaneous sensing and therapy for oral diseases.

An optimized caries model of Streptococcus mutans in rats and its application for evaluating prophylactic vaccines

Dental caries is a prevalent oral disease that mainly results from Streptococcus mutans. Susceptibility to S. mutans decreased rapidly after weaning in a well-known rat model. However, owing to the lack of time to establish protective immunity ahead of challenge, the weaning rat model is suboptimal for assessing prophylactic vaccines against S. mutans infection. In this study, we found that, in adult rats, S. mutans cultured under air-restricted conditions showed dramatically increased colonization efficacy and accelerated development of dental caries compared with those cultured under air-unrestricted conditions. We propose that S. mutans cultured under air-restricted conditions can be used to develop an optimal caries model, especially for the evaluation of prophylactic efficacy against S. mutans. Therefore, we used the anti-caries vaccine, KFD2-rPAc, to reevaluate the protection against the challenge of S. mutans. In immunized rats, rPAc-specific protective antibodies were robustly elicited by KFD2-rPAc before the challenge. In addition to inhibiting the initial and long-term colonization of S. mutans in vivo, KFD2-rPAc immunization showed an 83% inhibitory efficacy against the development of caries, similar to that previously evaluated in a weaning rat model. These results demonstrate that culturing under air-restricted conditions can promote S. mutans infection in adult rats, thereby helping establish a rat infection model to evaluate the prophylactic efficacy of vaccines and anti-caries drugs.

Assessment of oral hygiene parameters in association to eating behaviors and healthy eating self-efficacy in school-aged children

BACKGROUND

Eating behavior are a broad category influenced by a various personal, social, cultural, environmental, and economic factors. The objective of this study was to evaluate the oral hygiene status of school-aged children in relation to their eating behavior and healthy eating self-efficacy.

METHODS

The study was carried out with the participation of 225 children aged 7-9 years. Parents carried out the Children's Eating Behavior Questionnaire (CEBQ) to assess eating behaviors and provided sociodemographic information. Oral examinations of the children were provided according to plaque index (PI), gingival index (GI), simplified oral hygiene index (OHI-S), dmft and DMFT and, the Healthy Eating Self-Efficacy Scale (HESES) was administered to the children. For statistical analysis, a consistent partial least squares structural equation model (PLS-SEM) technique was utilized.

RESULTS

A statistically significant negative correlation was found between the Healthy Eating Self-Efficacy Scale and the PI, GI, OHI-S, dmfs (p < 0.001) and DMFS (p = 0.002). Emotional undereating significantly negatively affected dmfs (p = 0.021), while emotional overeating had a significant positive effect on DMFS (p = 0.036). None of the eating behavior subgroups in children showed a significant relationship with self-efficacy. Additionally, higher self-efficacy (p = 0.001) and food fussiness (p = 0.001) were found in children from high-income families, while emotional overeating (p < 0.001) and desire to drink (p = 0.009) were observed in children from middle-income families.

CONCLUSION

This study reveals a significant relationship between healthy eating self-efficacy and oral hygiene in children. Higher self-efficacy correlates with better oral health, while emotional eating negatively impacts dental outcomes. Socioeconomic factors also play a role, suggesting that interventions should target self-efficacy and emotional eating to improve both eating behaviors and oral health in school-aged children.

Overdiagnosis of dental caries in South Korea: a pseudo-patient study

BACKGROUND

To evaluates the tendency of South Korean dentists to over-diagnose clinically healthy teeth in pseudo-patients.

METHODS

We conducted a pseudo-patient, cross-sectional study in 196 private dental clinics with 58 pseudo-patients in South Korea between August and December 2018. Trained pseudo-patients with no previous oral diseases, including dental caries, diagnosed by two experienced dentists, were sent to each dental clinic. Before visiting each private dental clinic, participants were instructed to state, "I have no symptoms, but I would like to have a dental caries examination". The oral examination was performed using visual and tactile inspection methods only. The interactions between the dental clinic staff and the pseudo-patient were documented on a data collection form shortly after each visit.

RESULTS

In 33.2% (65/196) of these interactions, the pseudo-patients were diagnosed as having no dental caries. 11.7% (23/196), 12.8% (25/196), 10.7% (21/196), and 10.7% (21/196) of the sample were diagnosed with dental caries in one, two, three, and four teeth, respectively. Dentists diagnosed five or more dental caries in 20.9% (41/196) of the sample. 196 dental clinics diagnosed a total of 503 dental caries. Of these, 392 were in molars. Small solo practice dentists diagnosed 3.54 dental caries and large group practice dentists 1.57, but the difference was not significant (p = 0.07). The recommendation rate for dental caries treatment was highest among 43 (55.1%) large solo practices, and lowest in 7 (33.3%) large group practices. However, small solo practices had the lowest rate of preventive care recommendations at 12 (30.8%) and 10 (47.6%) in large group practices. The data shows that preventive care recommendations increased as the practice size increased.

CONCLUSION

The study findings indicate that Korean dentists tend to over-diagnose dental caries, which could pose a threat to public health both in Korea and worldwide. Therefore, it is important to carefully consider strategies to improve the correct diagnosis and standard of care for dental caries by private dentists.

Dental resin for periodontal and tooth root regeneration via metformin to enhance osteogenic and cementogenic differentiation of human periodontal ligament stem cells

OBJECTIVES

This study developed a novel dental resin incorporating metformin to repair root caries and periodontitis defects. The objectives were to: (1) Develop a novel dental resin with metformin release to fulfill the clinical requirements for mechanical properties; and (2) investigate the metformin release pattern and the effects on osteogenic and cementogenic differentiation of human periodontal ligament stem cells (hPDLSCs).

METHODS

Resin specimens with different concentrations of metformin were fabricated. Metformin release was measured using high-performance liquid chromatography. Cellular growth and proliferation on resin were assessed. Alizarin red S staining and an alkaline phosphatase (ALP) activity were determined. Quantitative real-time reverse transcription PCR was employed to determine osteogenic and cementogenic differentiation.

RESULTS

The resin with 7.5 % metformin had mechanical properties comparable to those of a commercial control, thus satisfying the clinical requirements (mean ± SD; n = 10). hPDLSCs showed robust growth and proliferation on resin. At 14 days, the number of hPDLSCs increased by four-fold (p > 0.1). ALP activity in the metformin group was 1.8 times higher than that of control (p < 0.05). At 21 days, the metformin group showed a significant increase in mineral synthesis. Metformin group had cementogenic and osteogenic differentiation values that were 2.5 and 2.3 times higher, respectively, than control without metformin (p < 0.05).

SIGNIFICANCE

A metformin-resin was formulated that greatly promoted both cementogenic and osteogenic differentiation for the first time. This resin was mechanically strong and supported hPDLSC adhesion, growth and proliferation. This resin substantially enhanced hPDLSC osteogenic and cementogenic differentiation, yielding mineral synthesis of hPDLSCs more than 2-fold that of control without metformin. This new metformin-resin shows promise for the restoration of tooth root caries and the regeneration of periodontal tissues including alveolar bone and cementum.

Resin infiltrant with antibacterial activity: effects of incorporation of DMAHDM monomer and NACP on physical and antimicrobial properties

OBJECTIVES

Considering the fact that resin infiltrants lack antibacterial activity, this study assessed the influence of the quaternary ammonium monomer dimethylaminohexadecyl methacrylate (DMAHDM) and amorphous calcium phosphate nanoparticles (NACP) on the physical and antibacterial properties of an experimental resin infiltrant (ERI).

METHODOLOGY

The following groups were established: ERI (75/25 wt.% TEGDMA/BISEMA), ERI + 2.5% DMAHDM (2.5DM), ERI + 5% DMAHDM (5DM), ERI + 2% NACP (NACP), ERI + 2.5% DMAHDM + 2% NACP (2.5DM_NACP), ERI + 5% DMAHDM + 2% NACP (5DM_NACP), and Icon® (IC), a commercial resin infiltrant. Degree of conversion (DC; n=4), sorption and solubility (SO/SOL; n=8), and contact angle (CA; n=10) tests were conducted. Biofilm biomass (BB; n=6) and bacterial metabolism (BM; n=8) were evaluated after Streptococcus mutans (UA159) cultivation for 48 h on material samples. Data were evaluated by one-way ANOVA and Tukey or Games-Howell post hoc tests (α=0.05).

RESULTS

IC exhibited the highest DC, with no difference from 2.5DM and 5DM. IC showed the lowest CA. IC had the lowest SO, followed by ERI, which had the lowest SOL, with no difference from IC. 5DM_NACP showed the lowest biofilm biomass, similar to 2.5DM and 5DM. Resin infiltrants containing DMAHDM showed reduced bacterial metabolism.

CONCLUSIONS

DMAHDM, with or without NACP, demonstrated significant antibacterial activity, while NACP impaired DC. Both DMAHDM and NACP increased the contact angle, sorption, and solubility of the resin infiltrant, which may affect the material's clinical performance.

Alterations in salivary profile in individuals with dental caries and/or obesity: A systematic review and meta-analysis

OBJECTIVES

To investigate current evidence on the association of salivary profile with dental caries and obesity.

DATA/SOURCES

A comprehensive search was conducted on PubMed, Web of Science, Embase, ProQuest Medical Database, ProQuest Sci-Tech Premium, and Cochrane Library up to June 2024. Observational studies comparing salivary profiles in individuals with dental caries and/or obesity were included. The risk of bias was evaluated using the Newcastle-Ottawa Scale. Meta-analysis was utilised to estimate the overall weighted or standardised mean differences (WMD or SMD).

STUDY SELECTION

Fifty studies were included, comprising 47 cross-sectional studies and three longitudinal studies with only baseline data extracted. Meta-analysis demonstrated that individuals with caries had higher total antioxidant capacity (SMD: 1.78, P<0.001) and elevated levels of interleukin-6 (SMD: 3.41, P=0.004) and tumour necrosis factor-α (SMD: 0.61, P=0.005) in unstimulated whole saliva (UWS) compared to caries-free controls. Individuals with overweight/obesity, when compared to normal-weight counterparts, showed decreased UWS pH (WMD: -0.14, P=0.009), unstimulated and stimulated salivary flow rates (WMD: -0.09 mL/min, P=0.001 and WMD: -0.35 mL/min, P<0.001, respectively), phosphorus/phosphate levels in stimulated whole saliva (SWS) (SMD: -0.36, P=0.004), and peroxidase levels in both UWS (SMD: -1.56, P<0.001) and SWS (SMD: -1.10, P<0.001). Additionally, they exhibited higher salivary levels of mutans streptococci (SMD: 0.47, P<0.001), secretory immunoglobulin A (WMD: 14.51 μg/mL, P=0.020), and total antioxidant capacity in UWS (SMD: 0.67, P<0.001).

CONCLUSION

Although individuals with dental caries and/or obesity have altered salivary profiles, the quality of evidence remains low. Further high-quality studies are required to investigate the triadic associations in depth.

CLINICAL SIGNIFICANCE

Monitoring salivary parameters and biomarkers could serve as a relatively simple and non-invasive method for identifying, predicting, controlling, and monitoring individuals at high risk of dental caries and obesity. This knowledge can inform the development of tailored oral health promotion programs for individuals with obesity.

The anti-caries effects of copper tetraamine fluoride on enamel: An in vitro study

OBJECTIVE

To investigate the antibacterial, remineralising, and discolouring effects of copper tetraamine fluoride (CTF) on artificial enamel caries.

METHOD

Human enamel blocks with artificial caries were treated with CTF, silver diamine fluoride (SDF, positive control) and water (negative control) before being challenged with Streptococcus mutans. The morphology, viability, and growth kinetics of biofilm were evaluated using scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM), and colony-forming unit (CFU) counting. The lesion depths, mineral loss, micro-hardness, and crystal characteristics were assessed using micro-computed tomography, Knoop Hardness Tester, and X-ray diffraction (XRD), respectively. The discolouring property was assessed by spectrophotometry.

RESULTS

SEM showed that bacteria completely covered the enamel surface treated with water, but not the enamel surface treated with CTF and SDF. CLSM showed dead-to-live ratio of biofilm treated with CTF, SDF and water were 0.8 ± 0.1, 0.9 ± 0.2 and 0.5 ± 0.1 (p < 0.001, CTF, SDF>Water). Log10 CFU values of biofilm treated with CTF, SDF and water were 7.7 ± 0.2, 7.7 ± 0.1 and 8.1 ± 0.1 (p < 0.001, CTF, SDFWater). XRD revealed well-crystallised hydroxyapatite in enamel treated with CTF and SDF, but not water. Spectrophotometry showed ΔE values of the CTF, SDF and water groups were 5 ± 3, 54 ± 6 and 6 ± 2 (p < 0.001, CTF, water

CONCLUSION

CTF inhibited Streptococcus mutans biofilm and remineralised artificial enamel caries without discolouration.

CLINICAL SIGNIFICANCE

If CTF is successfully translated into clinical use, it can be a simple agent for clinicians to arrest enamel caries.

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Key Words

• Antibacterial
• Caries
• Enamel
• Fluoride
• Remineralization

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MESH Headings

• Dental Enamel/drug effects
• Humans
• Biofilms/drug effects
• Streptococcus mutans/drug effects
• Dental Caries/microbiology
• Microscopy, Electron, Scanning
• X-Ray Microtomography
• Hardness
• Cariostatic Agents/pharmacology
• X-Ray Diffraction
• Silver Compounds/pharmacology
• Fluorides, Topical/pharmacology
• Quaternary Ammonium Compounds/pharmacology
• Anti-Bacterial Agents/pharmacology
• Microscopy, Confocal
• Tooth Remineralization/methods
• Materials Testing
• Water/chemistry

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Affiliation(s)

Veena Wenqing Xu Faculty of Dentistry, University of Hong Kong, Hong Kong, China
Iris Xiaoxue Yin Faculty of Dentistry, University of Hong Kong, Hong Kong, China
John Yun Niu Faculty of Dentistry, University of Hong Kong, Hong Kong, China
Ollie Yiru Yu Faculty of Dentistry, University of Hong Kong, Hong Kong, China
Mohammed Zahedul Islam Nizami Faculty of Dentistry, University of Hong Kong, Hong Kong, China; Department of Mineralized Tissue Biology and Bioengineering, The ADA Forsyth Institute, Cambridge, MA, USA.
Chun Hung Chu Faculty of Dentistry, University of Hong Kong, Hong Kong, China.

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Optimal storage time and temperature of human oral samples to minimize microbiome changes: A scoping review

Improper storage times and temperatures negatively impact the quality of biospecimens with oral microbiomes. This study aimed to determine the optimal storage time and temperature for maintaining the integrity of human dental plaque and saliva samples' microbial profiles. A comprehensive search yielded 5433 studies, with 12 meeting inclusion criteria. The number of studies on the storage time and temperature for plaque or saliva samples was extremely limited, with large variability in study designs and analytical tools. The best approach for dental plaque and saliva samples was to immediately freeze fresh specimens at - 80 °C or lower until DNA extraction, with a recommended storage time not exceeding 1-2 years, regardless of temperature. Checkerboard DNA-DNA hybridization-based studies suggested dental plaque storage at - 20 °C for 6 months, but a shorter duration was advised. Based on 16 S rRNA gene sequencing studies, dental plaque samples could be stored at - 80 °C for 6 months in 75 % ethanol or Bead Solution. Dental plaque and saliva samples could be stored at room temperature for 1-2 weeks without significant microbiome changes if stored in appropriate media. Further well-designed randomized controlled studies with longer-storage duration are necessary to establish more definitive guidelines.

Black Phosphorus Nanosheets-Loaded Mussel-Inspired Hydrogel with Wet Adhesion, Photothermal Antimicrobial, and In Situ Remineralization Capabilities for Caries Prevention

The main features of early caries are the massive colonization of cariogenic bacteria and demineralization of tooth enamel by the acids that they produce. Owing to the lack of effective treatments, the development of anticaries therapeutics with both antimicrobial and remineralizing properties is urgently required. Black phosphorus nanosheets (BPNs) are ideal therapeutics for the treatment of early caries because they can mediate photothermal antibacterial activity and subsequently promote remineralization by generating PO4 3-. However, the dynamic and wet environment of the oral cavity prevents the long-term adhesion of BPNs to the tooth surface. In this study, using catechol-modified chitosan and PLGA-PEG-PLGA as raw materials, a mussel-inspired versatile hydrogel, BP@CP5, is presented that can be used to physically load BPNs. BP@CP5 has exceptional injectability and can firmly adhere to tooth surfaces for up to 24 h. Upon irradiation, BP@CP5 can quickly eliminate ≈99% of Streptococcus mutans and Streptococcus sanguinis; furthermore, the PO4 3- generated via degradation also promotes rapid remineralization of enamel slabs. Importantly, the vivo rodent caries modeling results further confirm the excellent caries-prevention properties of BP@CP5. This study demonstrates that BP@CP5 is a promising anticaries material for caries management.

Frontiers of Global Research Trend on Root Caries: A Bibliometric Analysis

OBJECTIVE

This study aimed to examine the global research trend and frontiers in the field of root caries.

METHODS

Two independent investigators searched the Web of Science Core Collection to include journal articles published on root caries from 1994 to 2023. They examined citation trends of the selected publications and performed bibliometric analysis using VOSviewer. Cooccurrence and cocitation analysis were used to calculate the burst strength of the most cited keywords and the most cited publications.

RESULTS

This study included 1144 publications (1004 scientific research articles and 140 review articles) for bibliometric analysis. The number of publications from 2018 to 2023 was 404, accounting for 35% (404/1144) over the last 30 years. The annual citation count showed a gradual upward trend with a surge from 2018. The cooccurrence analysis classified the publications into four clusters which were in vitro studies, prevention, microbiology, and epidemiology. Cocitation analysis revealed silver diamine fluoride, systematic review, and randomized clinical trial were the three main keywords; and their citation burst strength (period) were 17.2 (2017-2023), 9.4 (2015-2023), and 6.9 (2018-2023), respectively. Noninvasive treatment of root caries (narrative review), aetiology of root caries (narrative review), and use of silver diamine fluoride in arresting root caries (clinical trial) were the topics (publication type) of the three most cited publications; and their burst strength (period) were 8.9 (2017-2020), 5.9 (2017-2021), and 4.7 (2015-2018), respectively.

CONCLUSION

This study highlights the recent growing research interest in root caries, particularly on its microbiology, prevention, and the use of silver diamine fluoride.

Antibacterial and mineralising properties of copper tetraamine fluoride on dentine caries: A laboratory study

OBJECTIVE

To investigate the antibacterial, mineralising, and discolouring properties of copper tetraamine fluoride (CTF) on artificial dentine caries.

METHOD

Demineralised human dentine blocks were treated with CTF, silver diamine fluoride (SDF, positive control) and water (negative control) before they were subjected to cariogenic challenge with Streptococcus mutans biofilm. The morphology, viability, and growth kinetics of the biofilm were assessed by scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM), and colony-forming unit (CFU) counting. The lesion depths, mineral loss, chemical structure, and crystal characteristics were measured using micro-computed tomography, Fourier transform infrared (FTIR), and X-ray diffraction (XRD). The discolouring property on demineralised dentine was assessed by spectrophotometry. One-way analysis of variance with the Bonferroni post hoc test was performed to assess and compare the data.

RESULTS

SEM revealed confluent bacterial growth covering the surface of dentine treated with Water but not CTF and SDF. CLSM showed the dead-to-live ratio of the biofilm treated with CTF, SDF and Water were 0.7 ± 0.1, 0.8 ± 0.1 and 0.5 ± 0.1 (p < 0.001, CTF, SDF>Water). The Log10 CFU values of the biofilm treated with CTF, SDF and Water were 7.8 ± 0.1, 7.8 ± 0.1 and 8.1 ± 0.2 (p < 0.001, CTF, SDF

CONCLUSION

CTF inhibited Streptococcus mutans. It mineralised but not discoloured artificial dentine caries.

CLINICAL SIGNIFICANCE

If CTF is successfully translated into clinical application, it may be a non-discolouring anti-caries agent for clinicians to arrest dentine caries.

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Key Words

• Antibacterial
• Caries
• Dentine
• Fluoride
• Remineralization

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MESH Headings

• Dentin/drug effects
• Humans
• Biofilms/drug effects
• Dental Caries/microbiology
• Anti-Bacterial Agents/pharmacology
• Streptococcus mutans/drug effects
• X-Ray Microtomography
• Spectroscopy, Fourier Transform Infrared
• Microscopy, Electron, Scanning
• Quaternary Ammonium Compounds/pharmacology
• Quaternary Ammonium Compounds/chemistry
• X-Ray Diffraction
• Silver Compounds/pharmacology
• Microscopy, Confocal
• Cariostatic Agents/pharmacology
• Cariostatic Agents/therapeutic use
• Cariostatic Agents/chemistry
• Fluorides, Topical/pharmacology

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Affiliation(s)

Veena Wenqing Xu Faculty of Dentistry, University of Hong Kong, Hong Kong, China
Iris Xiaoxue Yin Faculty of Dentistry, University of Hong Kong, Hong Kong, China
John Yun Niu Faculty of Dentistry, University of Hong Kong, Hong Kong, China
Ollie Yiru Yu Faculty of Dentistry, University of Hong Kong, Hong Kong, China
Mohammed Zahedul Islam Nizami Faculty of Dentistry, University of Hong Kong, Hong Kong, China; Department of Mineralized Tissue Biology and Bioengineering, The ADA Forsyth Institute, Cambridge, MA, USA.
Chun Hung Chu Faculty of Dentistry, University of Hong Kong, Hong Kong, China.

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Temporin-Derived Peptides Disrupt the Exopolysaccharide Matrix of Streptococcus mutans to Prevent Related Dental Caries

Dental caries, the most prevalent oral infectious disease, is closely associated with Streptococcus mutans. This study investigates the antimicrobial properties of the temporin-GHb peptide and its derivatives (GHbR, GHbK, and GHb3K) against S. mutans. These peptides exhibited potent anti-S. mutans activity through a membrane-disruptive mechanism, confirmed by flow cytometry and fluorescence staining assays while showing lower bactericidal effects on beneficial probiotic bacteria. Additionally, they inhibited the biofilm matrix formation by disrupting extracellular polysaccharide (EPS) synthesis, as demonstrated by zymography, qRT-PCR, and sucrose metabolism experiments. In a rat model of S. mutans-induced dental caries, treatment with these peptides significantly reduced the incidence of dental lesions. H&E staining analysis of rat oral tissues confirmed the biosafety of GHb and GHb3K. These findings suggest that temporin-derived peptides effectively target EPS, inhibiting biofilm formation and virulence, offering a promising strategy for preventing dental caries and promoting oral health. The findings suggest potential applications for peptide-based interventions to mitigate biofilm-related issues across various fields, including agriculture, food processing, and healthcare.

New insights into the correlation between bone mineral density and dental caries in NHANES 2011-2016

OBJECTIVES

Investigate the relationship between bone mineral density (BMD) at various body sites and dental caries.

MATERIALS AND METHODS

Based on the National Health and Nutrition Examination Survey (NHANES) database from 2011 to 2016, the correlation between BMD at various body sites and the DMFS index among 7044 adults aged 20-59 years was analyzed. Multiple linear regression, restricted cubic splines (RCS), piecewise linear regression, logistic regression, weighted quantile sum regression (WQS) and mediation effects analysis were integrated to explore the relationship between BMD and dental caries.

RESULTS

Under the linear assumption, except for arm BMD, the BMDs of all other sites are negatively correlated with the DMFS index of dental caries. RCS analysis indicates a U-shaped relationship between head BMD and the DMFS index (p for nonlinear < 0.0001). WQS analysis indicates that mixed BMD is significantly negatively correlated with the DMFS index for dental caries (estimate, - 0.023; 95% CI, - 0.025 ~ - 0.020), and head BMD has the most significant impact on the DMFS index (weight = 91.4%). Simple mediation analysis of the effect of dental caries on BMD levels mediated by inflammation levels showed negative results, suggesting that dental caries may not influence BMD through inflammation levels.

CONCLUSION

Monitoring BMD should be combined with appropriate oral healthcare and caries management strategies to effectively address these interconnected health issues, and particular attention should be paid to the monitoring of head BMD.

A cluster randomized trial of xylitol chewing gum for prevention of preterm birth: The PPaX trial

BACKGROUND

Maternal periodontal disease is associated with preterm and low-birthweight deliveries, but randomized trials of likely efficacious treatments (e.g., dental scaling and root planing) during pregnancy have not reduced these adverse outcomes. As an alternative, we hypothesized that periconception initiation of xylitol chewing gum would reduce the occurrence of preterm or low-birthweight deliveries among a historical high-prevalence population in Malawi.

METHODS

We conducted an open-label, parallel-enrollment, matched-pair, cluster-randomized, controlled clinical trial across eight health centers (sites) in and around Lilongwe, Malawi. Sites were paired by anticipated delivery volume and randomized to prenatal and oral health education alone (active control) or with twice-daily xylitol chewing gum (intervention) throughout the periconception and antenatal periods. For the primary prevention of preterm (<37 weeks) and low-birthweight (<2,500 g) deliveries (co-primary outcomes), comparison by allocation group was performed using generalized linear mixed models for each outcome as a fixed factor and the site(s) as a random factor.

FINDINGS

10,069 participants were enrolled (n = 4,549 at intervention sites, n = 5,520 at active control sites), with >95% available for analyses. Initiation of xylitol chewing gum resulted in significant reductions in the co-primary outcomes: preterm birth (12.6% [549/4,349] vs. 16.5% [878/5,321]; relative risk [RR] 0.76, 95% confidence interval [CI] 0.57-0.99) and <2,500-g neonates (8.9% [385/4,305] vs. 12.9% [679/5,260]; RR 0.70, 95% CI 0.49-0.99). Xylitol chewing gum use also led to fewer neonatal demises (0.2% [8/4,305] vs. 0.4% [22/5,260]; RR 0.41, 95% CI 0.19-0.89).

CONCLUSIONS

Periconception initiation and ongoing use of xylitol chewing gum significantly reduced the occurrence of preterm and low-birthweight deliveries in Malawi.

FUNDING

E.W. Al Thrasher Foundation (to K.A.) and USAID Saving Lives at Birth Grand Challenges Grant AID-OAA-G-11-00062 (to K.A.). Additional financial and in-kind support was graciously provided by Texas Children's Hospital and Baylor Foundation Malawi.

Exploring time-killing and biofilm inhibition potential of bioactive proteins extracted from two varieties of Pleurotus ostreatus

Introduction

Dental caries, caused by oral microbial pathogens, are a global health concern, further exacerbated by the presence of methicillin-resistant Staphylococcus aureus (MRSA). Bioactive proteins and peptides (BAPs) exhibit potent antimicrobial properties, targeting multiple cellular mechanisms within pathogens, reducing the likelihood of resistance development. Given the antimicrobial potential of BAPs, this study aimed to compare the efficacy of BAPs extracted from cultivated (Pleurotus ostreatus, PoC) and wild (Pleurotus ostreatus, PoW) mushrooms against pathogens responsible for dental caries.

Methods

BAPs were extracted from both PoC and PoW using a TCA-acetone method. Antimicrobial activities were tested against seven bacteria and one fungus using agar well diffusion and MIC determination. Antibiofilm activity was assessed via modified CV assay, while DPPH and erythrocyte lysis tests evaluated free radical scavenging.

Results

PoC showed superior antimicrobial efficacy, with lower MIC and MBC values, and disrupted biofilm integrity at increasing concentrations. PoW exhibited better antioxidant activity with higher DPPH scavenging, though its antimicrobial efficacy was slightly lower than PoC.

Discussion

Both PoC and PoW BAPs inhibited dental pathogens, with PoC showing stronger inhibition against MRSA and nystatin-resistant Candida albicans. This suggests BAPs may target additional cellular mechanisms beyond membranes, PBPs, and ergosterols. Despite PoW's stronger antioxidant properties, both BAPs had comparable antibiofilm activity. These findings suggest complementary actions of BAPs from PoC and PoW both, in treating dental caries, offering broad-spectrum antimicrobial and antioxidant benefits.

A Novel Nano-Hydroxyapatite Agarose-Based Hydrogel for Biomimetic Remineralization of Demineralized Human Enamel: An in-vitro Study

Purpose

This study aims to investigate the biomimetic effect of agarose hydrogel loaded with enamel matrix derivative (EMD-agarose) alone or in combination with nano-hydroxyapatite (n-HA-EMD-agarose) on the remineralization of human demineralized enamel.

Methods

Extracted human mandibular third molars were sectioned into 54 buccal and lingual halves. Acid-resistant nail varnish was applied to each half, except for two enamel windows. Enamel surface microhardness, energy-dispersive X-ray spectroscopy (EDX), and scanning electron microscopy (SEM) analyses were conducted to evaluate enamel surfaces at baseline, following demineralization with 37% phosphoric acid, and after each hydrogel application and remineralization for two, four, and six days. Remineralization was performed using a phosphate solution at 37°C.

Results

At day 6 following remineralization, a statistically significant higher mean microhardness was recorded in n-HA-EMD-agarose hydrogel (260.87 ± 3.52) as compared to EMD-agarose hydrogel (244.63 ± 2.76) (p = 0.027). Similarly, n-HA-EMD-agarose hydrogel showed a higher mean calcium (46.31 ± 2.78), phosphorous (24.92 ± 0.826), and fluoride (0.909 ± 0.053) weight percentage compared to EMD-agarose hydrogel calcium (19.64 ± 1.092), phosphorous (19.64 ± 1.092), and fluoride (0.7033 ± 0.0624) weight percentage (p < 0.05). Further, SEM analysis revealed a substantial deposition of n-HA following the application of the n-HA-EMD-agarose hydrogel, whereas the EMD-agarose exhibited a relatively smooth enamel surface with less visible enamel rods due to mineral deposition.

Conclusion

The combined n-HA-EMD-agarose hydrogel demonstrated improved surface microhardness of the remineralized enamel and enhanced mineral content deposition, indicating its potential as a biomimetic approach for dental enamel repair.

Developing a novel antibacterial copper tetraamine fluoride

OBJECTIVE

To develop a novel and biocompatible copper tetraamine fluoride (CTF) with antibacterial and nondiscolouring properties.

METHOD

This study used copper fluoride and ammonia solution to develop CTF solution. The CTF was characterized by X-ray photoelectron spectroscopy (XPS). Cytotoxicity was evaluated by stem cells from human exfoliated deciduous teeth (SHED) and human gingival fibroblasts (HGF-1). The fluoride concentration was determined using ion-selective electrode. The alkalinity was measured by a pH electrode. The human dentine blocks were treated with CTF and then incubated with Streptococcus mutans to evaluate the antimicrobial and discolouring effects. The silver diamine fluoride (SDF) was employed as the positive control, and water was the negative control. The colony-forming units (CFUs) and confocal laser scanning microscopy (CLSM) were used to examine the kinetics and viability of the biofilm. The discolouring property on dentine was assessed by spectrophotometry. One-way analysis of variance with the Bonferroni post hoc test was performed to assess and compare the data.

RESULTS

XPS confirmed synthesis of CTF solution. The half-maximal inhibitory concentration of CTF on SHED and HGF-1 was 195±16 ppm and 137±11 ppm. The fluoride concentration was 121,000±5,000 ppm. The pH value was 9. Log10 CFU of the CTF, SDF and water group were 5.0 ± 0.2, 4.9 ± 0.1 and 7.4 ± 0.1 (p < 0.001, CTF, SDFWater). Spectrophotometry showed that the ΔE of the CTF, SDF and water group were 5 ± 2, 6 ± 3 and 45±2 (p < 0.001, CTF, Water

CONCLUSION

This study developed an alkaline 58% CTF solution, which is biocompatible, antibacterial and non-discolouring.

CLINICAL SIGNIFICANCE

If CTF is successfully translated into clinical care, CTF can be a simple and affordable anti-caries agent for clinicians to prevent dental caries.

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Key Words

• Antibacterial
• Caries
• Copper
• Dentine
• Fluoride

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MESH Headings

• Humans
• Anti-Bacterial Agents/pharmacology
• Streptococcus mutans/drug effects
• Fibroblasts/drug effects
• Tooth, Deciduous/drug effects
• Hydrogen-Ion Concentration
• Biofilms/drug effects
• Quaternary Ammonium Compounds/pharmacology
• Quaternary Ammonium Compounds/chemistry
• Copper/pharmacology
• Copper/chemistry
• Gingiva/drug effects
• Gingiva/cytology
• Dentin/drug effects
• Photoelectron Spectroscopy
• Stem Cells/drug effects
• Silver Compounds/pharmacology
• Microscopy, Confocal
• Biocompatible Materials/pharmacology
• Fluorides, Topical/pharmacology
• Fluorides/pharmacology
• Ion-Selective Electrodes
• Cariostatic Agents/pharmacology
• Cariostatic Agents/chemistry
• Materials Testing
• Microbial Sensitivity Tests
• Cell Survival/drug effects

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Grants Collapse

Affiliation(s)

Veena Wenqing Xu Faculty of Dentistry, University of Hong Kong, Hong Kong, China
Iris Xiaoxue Yin Faculty of Dentistry, University of Hong Kong, Hong Kong, China
John Yun Niu Faculty of Dentistry, University of Hong Kong, Hong Kong, China
Ollie Yiru Yu Faculty of Dentistry, University of Hong Kong, Hong Kong, China
Mohammed Zahedul Islam Nizami Faculty of Dentistry, University of Hong Kong, Hong Kong, China; Department of Mineralized Tissue Biology and Bioengineering, The Forsyth Institute, Cambridge, MA, USA.
Chun Hung Chu Faculty of Dentistry, University of Hong Kong, Hong Kong, China.

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The Identification of Oral Cariogenic Bacteria through Colorimetric Sensor Array Based on Single-Atom Nanozymes

Effective identification of multiple cariogenic bacteria in saliva samples is important for oral disease prevention and treatment. Here, a simple colorimetric sensor array is developed for the identification of cariogenic bacteria using single-atom nanozymes (SANs) assisted by machine learning. Interestingly, cariogenic bacteria can increase oxidase-like activity of iron (Fe)─nitrogen (N)─carbon (C) SANs by accelerating electron transfer, and inversely reduce the activity of Fe─N─C further reconstruction with urea. Through machine-learning-assisted sensor array, colorimetric responses are developed as "fingerprints" of cariogenic bacteria. Multiple cariogenic bacteria can be well distinguished by linear discriminant analysis and bacteria at different genera can also be distinguished by hierarchical cluster analysis. Furthermore, colorimetric sensor array has demonstrated excellent performance for the identification of mixed cariogenic bacteria in artificial saliva samples. In view of convenience, precise, and high-throughput discrimination, the developed colorimetric sensor array based on SANs assisted by machine learning, has great potential for the identification of oral cariogenic bacteria so as to serve for oral disease prevention and treatment.

Dental caries and salivary alterations in patients with type 2 diabetes: A systematic review and meta-analysis

INTRODUCTION

The association between dental caries, salivary alterations, and type 2 diabetes (T2D) is inconclusive. This systematic review evaluated the caries status and salivary alterations in adults with T2D.

DATA

Observational studies (cross-sectional, case-control, or cohort studies) that evaluated the association between type 2 diabetes and dental caries and/or salivary changes were included.

SOURCES

Systematic searches of PubMed/Medline, Web of Science, Embase, and the Cochrane Library for relevant literature published up to January 2024 were performed.

STUDY SELECTION

Ninety-eight studies were selected from the 1981 records obtained after screening the databases. Thirty-nine studies that met the eligibility criteria were included in the qualitative synthesis, and twenty-eight of the included studies were suitable for the quantitative synthesis (meta-analysis).

RESULTS

The meta-analysis showed that compared to non-diabetic individuals, type 2 diabetic individuals had higher DMFT (mean difference: 2.27; 95 % CI, 1.31 to 3.22; P < 0.00001). Moreover, type 2 diabetic individuals had lower salivary flow rate (standardized mean difference: -2.62; 95 % CI, -4.38 to -0.86; P = 0.003), salivary pH (standardized mean difference: -1.35; 95 % CI, -1.89 to -0.80; P < 0.00001) and salivary buffering capacity (standardized mean difference: -0.60; 95 % CI, -0.93 to -0.27; P = 0.0004). Whereas DMFT (mean difference: -2.15; 95 % CI, -6.47 to 2.17; P = 0.33) and salivary buffering capacity (standardized mean difference: -0.05; 95 % CI, -0.48 to 0.37; P = 0.80) were not significantly different between individuals with well-controlled diabetes and those with poorly-controlled diabetes.

CONCLUSIONS

Type 2 diabetes may lead to an increased index of dental caries and a reduction in salivary flow rate, salivary pH, and salivary buffering capacity in adults.

CLINICAL SIGNIFICANCE

Individuals with type 2 diabetes exhibit an elevated risk of dental caries and salivary alterations that facilitate the progression of dental caries. It is recommended that dentists and endocrinologists focus their attention on the oral health of this population.

An In-vitro Evaluation of Tooth Discoloration and Shear Bond Strength of Glass Ionomer Cement Bonded to Tooth Surface Pretreated with Silver Diamine Fluoride and Glutathione Biomolecule

BACKGROUND

Silver diamine fluoride (SDF) is employed in caries prevention and treatment; however, tooth discoloration post treatment is a significant disadvantage, which can be reduced using glutathione (GSH), a water soluble tripeptide.

AIM

To evaluate and compare the effect of glutathione biomolecule (GSH) and potassium iodide (KI) along with SDF on tooth discoloration and shear bond strength of glass ionomer cement (GIC) on the tooth surface.

METHODS

Artificial caries were created on 48 extracted unblemished premolars and divided into four groups (SDF, SDF + KI, SDF + GSH, and Water). The solutions were applied according to the manufacturer's instructions, and the samples were incubated for 24 hours. The color assessment was recorded on days 1, 7, and 14 by using a spectrophotometer. Following the color assessment, all the treated samples were bonded with GIC. The shear bond strength was evaluated using a universal testing machine.

RESULTS

Mixing SDF with GSH initially reduced tooth discoloration. Although there was an increase in the discoloration after 2 weeks, it was still less when compared to the SDF group. The application of GSH and KI post SDF application had no significant difference in the shear bond strength of GIC on the tooth surface.

CONCLUSIONS

The use of GSH along with SDF helps in reducing the discoloration without compromising the shear bond strength.

Description of Streptococcus dentalis sp. nov., Streptococcus gingivalis sp. nov., and Streptococcus lingualis sp. nov., Isolated from Human Oral Cavities

We isolated three novel strains, S1T, S2T, and S5T, from human oral cavities and identified them as distinct novel species. All these strains are facultatively anaerobic, Gram-stain-positive, and non-flagellated bacteria. Their optimal growth conditions for these strains were observed in Columbia broth (CB) at 37 °C, pH 7.0, and in the absence of NaCl. Phylogenetic analyses, employing the 16S rRNA gene and whole-genome sequencing, confirmed that all three strains belong to the genus Streptococcus. The 16S rRNA gene sequences of strains S1T, S2T, and S5T showed the highest similarities to Streptococcus parasanguinis, 98.57%, 99.05%, and 99.05%, respectively, and the orthologous average nucleotide identity (OrthoANI) values between the three strains and S. parasanguinis were 93.82%, 93.67%, and 94.04%, respectively. The pairwise OrthoANI values between the novel strains were 94.37% (S1T-S2T), 95.03% (S2T-S5T), and 94.71% (S1T-S5T). All strains had C20:1 ω9c and summed feature 8 (C18:1 ω7c and/or C18:1 ω6c) as major cellular fatty acids. Additionally, diphosphatidylglycerol (DPG) and hydroxyphosphatidylethanolamine (OH-PE) were identified as major polar lipids. Menaquinone was undetected in all strains. The results from the phylogenetic, phenotypic, chemotaxonomic, and genotypic analyses collectively indicated that strains S1T, S2T, and S5T represent three distinct novel species within the genus Streptococcus, and we propose the names Streptococcus dentalis sp. nov. for strain S1T (= KCTC 21234T = JCM 36526T), Streptococcus gingivalis sp. nov. for strain S2T (= KCTC 21235T = JCM 36527T), and Streptococcus lingualis sp. nov. for strain S5T (= KCTC 21236T = JCM 36528T).

Assessment of Vitamin E and Glutathione Peroxidase Levels in Salivary Samples of Children With and Without Dental Caries in Erbil City, Iraq

INTRODUCTION

According to the classic understanding of the etiology of dental caries, an imbalance between demineralization and remineralization in the oral cavity is important. Salivary antioxidants, including glutathione peroxidase and vitamin E, can modulate oxidative stress.

METHODS

This cross-sectional study evaluated the levels of glutathione peroxidase and vitamin E in the saliva of 90 children from Erbil City. The children were further subdivided based on their caries status and membership in the caries-free group. SPSS software was used for statistical comparisons.

RESULTS

The difference in antioxidant levels between the groups was statistically significant. In children, a significant decrease in the levels of glutathione (1664.356 µM) and vitamin E (4.0844 nM) in caries-susceptible individuals was observed compared to those not affected by caries (glutathione, 1945.355 µM; vitamin E, 5.3240 nM).

CONCLUSION

The study postulates that lower levels of antioxidants are associated with dental caries and highlights the potential of glutathione and vitamin E for oral health protection. This calls for further exploration of the usefulness of these antioxidants as potential therapeutic mediators for dental care.

Exploring the Applications of Artificial Intelligence in Dental Image Detection: A Systematic Review

BACKGROUND

Dental care has been transformed by neural networks, introducing advanced methods for improving patient outcomes. By leveraging technological innovation, dental informatics aims to enhance treatment and diagnostic processes. Early diagnosis of dental problems is crucial, as it can substantially reduce dental disease incidence by ensuring timely and appropriate treatment. The use of artificial intelligence (AI) within dental informatics is a pivotal tool that has applications across all dental specialties. This systematic literature review aims to comprehensively summarize existing research on AI implementation in dentistry. It explores various techniques used for detecting oral features such as teeth, fillings, caries, prostheses, crowns, implants, and endodontic treatments. AI plays a vital role in the diagnosis of dental diseases by enabling precise and quick identification of issues that may be difficult to detect through traditional methods. Its ability to analyze large volumes of data enhances diagnostic accuracy and efficiency, leading to better patient outcomes.

METHODS

An extensive search was conducted across a number of databases, including Science Direct, PubMed (MEDLINE), arXiv.org, MDPI, Nature, Web of Science, Google Scholar, Scopus, and Wiley Online Library.

RESULTS

The studies included in this review employed a wide range of neural networks, showcasing their versatility in detecting the dental categories mentioned above. Additionally, the use of diverse datasets underscores the adaptability of these AI models to different clinical scenarios. This study highlights the compatibility, robustness, and heterogeneity among the reviewed studies. This indicates that AI technologies can be effectively integrated into current dental practices. The review also discusses potential challenges and future directions for AI in dentistry. It emphasizes the need for further research to optimize these technologies for broader clinical applications.

CONCLUSIONS

By providing a detailed overview of AI's role in dentistry, this review aims to inform practitioners and researchers about the current capabilities and future potential of AI-driven dental care, ultimately contributing to improved patient outcomes and more efficient dental practices.

Tertiary Lymphoid Structure in Dental Pulp: The Role in Combating Bacterial Infections

Tertiary lymphoid structure (TLS) is associated with various pathologies, including those of cancers and chronic infections. Depending on the organ, multiple factors regulate the formation of TLS. However, the role of TLS in immune response and the molecules that drive its formation remain uncertain. The dental pulp, includes a few immune cells surrounded by rigid mineralized tissue, and opens to the outside through the apical foramen. Owing to this special organization, the dental pulp generates a directional immune response to bacterial infection. Considering this aspect, the dental pulp is an ideal model for comprehensively studying the TLS. In the present study, single-cell RNA sequencing of healthy and inflamed human dental pulp reveals known markers of TLS, including C-C motif chemokine ligand 19 (CCL19), lysosome-associated membrane glycoprotein 3 (LAMP3), CC chemokine receptor 7 (CCR7), and CD86, present in inflamed dental pulp. Compared with the healthy pulp, types and proportions of immune cells increase, along with enhanced cellular communication. Multiple immunofluorescence staining reveals that typical TLS emerges in dental pulp with pulpitis, consistent with the high expression of CC chemokine ligand 3 (CCL3), which may be a key driver of TLS formation. Moreover, TLS is also observed in a mouse model of pulpitis. These findings collectively offer insights into the formation and function of TLS in response to infection.

The effects of pregnancy on oral health, salivary ph and flow rate

BACKGROUND

The frequent occurrence of dental caries and periodontal diseases in women during pregnancy may be due to many factors, such as salivary variables. The aim of this study was to evaluate the effects of pregnancy on salivary pH, flow rate, the DMFT index, and CPI sores.

METHODS

A total of 198 volunteers (pregnant in different trimesters and non- pregnant) were included for the present observational cross-sectional study. Data about sociodemographic characteristics and dental and systemic health conditions were recorded. Unstimulated saliva samples were collected for 5 min via the spitting method. The pH of the saliva was measured by a portable pH meter. The salivary flow rate was determined by the weight measurement method. The DMFT index and CPI were determined. The statistical evaluation was performed using Robust ve Poisson Regression analyses (p < 0.05).

RESULTS

It was determined that there was a gradually significant decrease in the Ph value from the first trimester to the third trimester during pregnancy, which was lower than the control group. (p < 0.001) The flow rate of pregnants in their third trimester was lower than that of first trimester (p = 0.017). The CPI scores of pregnant women were significantly greater than that of non-pregnants (p = 0.042), while the DMFTs were similar among all groups.

CONCLUSION

Our findings indicate that pregnancy leads to a notable reduction in unstimulated salivary pH and flow rate, which also has a detrimental impact on periodontal health.

TRIAL REGISTRATION

Clinical Trials-ID: NCT06343337; Registration Date: 04.01.2024.

Association of vitamin D receptor gene polymorphisms with caries risk in children: a systematic review and meta-analysis

BACKGROUND

To investigate the association of vitamin D receptor (VDR) gene polymorphism with caries risk in children(< 18 years).

METHODS

The electronic databases PubMed, Cochrane, EMBASE, Web of Science, CNKI, Cqvip, and Wanfang were searched for observational studies on the relationship between VDR single nucleotide polymorphism(SNP) and caries, including cohort, case-control, and cross-sectional studies. Quality assessment of selected studies was conducted using the Newcastle Ottawa scale. Odds ratios (OR) with 95% confidence intervals (CI) values for associations of individual VDR SNP with dental caries were calculated based on four genetic models: allelic, recessive, dominant, and over-dominant.

RESULTS

Of 79 studies considered, 10 (nine case-control and one cross-sectional) were selected for analysis; the studies involved seven VDR SNPs: ApaI(rs7975232),BsmI(rs1544410),FokI(rs2228570),TaqI(rs731236), TaqI/BglI(rs739837), FokI(rs10735810) and Cdx-2(rs11568820). Alleles C and T of FokI(rs10735810) were significantly differently distributed in the caries and caries-free groups (OR = 1.33, 95% CI: 1.30-2.30, P = 0.03), with CC + CT genotypes at this locus associated with greater risk of developing caries than the TT genotype (OR = 1.87, 95%CI: 1.15-3.04, P = 0.01). Further, TT + CC genotype at TaqI(rs731236) was associated with a 1.33-fold higher risk of caries development than the TC genotype (OR = 1.33, 95%CI: 1.06-1.67, P = 0.02). On subgroup analysis, the association between TaqI(rs731236) and caries risk was affected by dentition type, and ethnicity (permanent dentition: OR = 1.48, 95%CI: 1.07-2.03, P = 0.02; Asian: OR = 1.38, 95%CI: 1.02-1.87, P = 0.03;). Genotype distributions at BsmI(rs1544410), TaqI/BglI(rs739837), FokI(rs2228570), and ApaI(rs7975232) did not differ significantly between the caries and caries-free groups.

CONCLUSIONS

Caries risk could be associated with TaqI(rs731236) and FokI(rs10735810) genotypes, and TaqI(rs731236) may be a risk factor for permanent teeth caries among Asian people.

Poverty Dynamics and Caries Status in Young Adolescents

OBJECTIVES

To investigate whether timing, accumulation and trajectories of poverty are associated with dental caries in young adolescents.

METHODS

The study was conducted within the Generation R Study, which is an ongoing population-based prospective cohort study conducted in Rotterdam, the Netherlands. This study included 2653 children. Information about household income and number of children and adults living in a household at six time points from pregnancy to 13 years old was retrieved from parental questionnaires to construct the poverty variable. Dental caries was assessed with the decayed, missing and filled teeth index through intraoral photographs at the age of 13 years. Sociodemographic and oral health-related characteristics were included as possible confounders. The association between poverty and dental caries was analysed on the basis of the three lifecourse theories, that is, critical period, cumulative risk and social mobility model. For the latter, we used latent class growth analysis (LCGA) to identify poverty trajectories over time. Next, the associations were studied with Hurdle Negative Binomial Models.

RESULTS

Poverty at birth and intermittent poverty up to the age of 13 were significantly associated with dental caries at 13 years of age (OR 1.41, 95% CI 1.01-1.99; OR 1.36, 95% CI 1.01-1.83 respectively) and with an increased mean number of decayed teeth by 34% (95% CI 1.02-1.76; 95% CI 1.05-1.71, respectively). LCGA showed four trajectories for the probabilities of poverty. All trajectories were significantly associated with dental caries at 13 years of age, with the 'downward mobility' trajectory showing the strongest association with dental caries (OR 1.55, 95% CI 1.05-2.29) and an increasing mean number of decayed teeth by 58% (95% CI 1.18-2.12) than the 'stable absent' trajectory.

CONCLUSION

Poverty at birth, intermittent poverty and downward poverty trajectory were associated with higher odds and higher mean number of decayed teeth at 13 years of age. The three lifecourse models influenced dental caries status during adolescence, hence strategies and policies targeted to improve socioeconomic conditions on deprived children should be implemented.

Social Inequalities and Geographical Distribution in Caries Treatment Needs among Schoolchildren Living in Buenos Aires City: A Cross-Sectional Study

BACKGROUND

Caries experience in Argentine children is quite high and no national data are present.

AIM

This cross-sectional observational survey aimed to assess the oral health status of schoolchildren in Buenos Aires (CABA) using CTNI and to evaluate the ecological association between health inequalities and caries prevalence.

DESIGN

Data were collected, via a clustered procedure, during the 2016-2018 school years. Children were examined at school to determine dental status according to the CTNI performed under standardized conditions, using light, dental mirrors, WHO probes and magnification (2.5×). Secondary sources were used to acquire socio-demographic and epidemiological data. A hierarchical cluster analysis was carried out with the municipalities of the CABA as the dependent variable and the socio-demographic factors.

RESULTS

The study population consisted of 62,904 schoolchildren, 43,571 of whom were enrolled into the study. Total caries prevalence was 67.78% while severe caries prevalence was 28.29%, which was statistically associated with the year of the survey (p < 0.01). Four territorial conglomerates from a socio-epidemiological standpoint outline homogeneous areas of social risk; cluster 1 had the highest social risk. The prevalence of severe caries (CTNI 7-14) was highest in cluster 1 (44.7-53.2% of the population).

CONCLUSION

The social inequalities between municipalities of the CABA were statistically associated with high inequalities in oral health needs.

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.

Applying Social Practice Theory to Explore Australian Preschool Children's Oral Health

INTRODUCTION

Despite substantial research and provision of dental care, significant morbidity remains for children's oral health. Guided by social practice theory (SPT), this research moves away from the often-ineffective focus on changing individual behavior to rethinking the centrality of the social world in promoting or undermining oral health outcomes. We define social practice as a routinized relational activity linking and integrating certain elements (competence, materials, and meanings) into the performance of a practice that is reproduced across time and space.

OBJECTIVE

To investigate oral health in preschool children in Perth, Western Australia, using social practice theory.

METHODS

With no definitive methodology for investigating SPT, we chose focused ethnography as a problem-focused, context-specific approach using mainly interviews to investigate participants' experience caring for their children's oral health. The focus of analysis was the practice of oral health care, not individual behavior, where themes identified from participants' transcripts were organized into categories of elements and performance.

RESULTS

Eleven parents, all of whom were married or partnered, were interviewed in 2021. Findings identified social practices relevant to oral health within parenting and family relations linked to routine daily activities, including shopping, consumption of food and beverages, and toothbrushing. Oral health literacy was reflected in integrating competence, materials, and meanings into performing oral health care, notably preferences for children to drink water over sugary beverages and information often being sourced from social media and mothers' groups rather than health providers.

CONCLUSION

Focusing on social practices as the unit of analysis offers a more layered understanding of elements in young children's oral health care that can indicate where the problem may lie. Findings provide an opportunity to consider future research and policy directions in children's oral health.

KNOWLEDGE TRANSFER STATEMENT

Examining social practices related to young children's oral health care identifies parents/carers' knowledge about, for example, toothbrushing, the resources required, and why toothbrushing is important. Analyzing these separate elements can reveal both enablers and barriers to oral health care. This provides researchers, clinicians and policymakers an opportunity to focus on not changing individual behavior but understanding how social context impacts parents/carers' capacity to make optimum decisions around young children's oral health.

Association between untreated caries and cariogenic bacteria in adolescents in Taiwan

Background/purpose

There is a paucity of research focused on salivary bacteria analyzed through real-time polymerase chain reaction (qPCR) among adolescents. The current study determined the quantity of Streptococcus mutans (SM) and Lactobacillus (LB) in saliva obtained from Taiwanese adolescents and investigated the association between the oral bacteria and untreated dental caries.

Materials and methods

This cross-sectional study recruited Taiwanese students aged 10-18. Saliva was collected using a Salivette kit and then analyzed through qPCR. The relative quantification values of SM and LB were coded based on mean fold ratios, with values > 2 coded as high and other values coded as low. Untreated dental caries was assessed through standard oral examinations. Univariate and multivariate logistic regression models were used to estimate the association between the levels of bacteria in the saliva of the study participants and the presence of untreated caries.

Results

The study involved 421 adolescents. 56 (13.3%) had both SM and LB values of >2 and were coded as having high levels of bacteria, whereas the other 365 (86.7%) students were coded as having low levels. The multivariate logistic regression analysis revealed that adolescents who had high combined salivary SM and LB levels had an odds ratio of having untreated dental caries of 2.05 (95% CI = 1.09, 3.86, P = 0.027) compared with those who had low salivary SM and LB levels.

Conclusion

The results of the present study indicate that salivary SM and LB levels are significantly associated with adolescents having untreated caries.

Association Between Age at First Birth and Long-Term Dental Caries Experience Among Women in the United States

Background: Pregnant women are at a higher risk of caries compared to nonpregnant women, and higher parity is a risk factor for untreated caries and tooth loss. However, it is unknown whether the timing of birth is associated with dental caries experience over time. Materials and Methods: This study is a cross-sectional study using the National Health and Nutrition Examination Survey (NHANES), 2011-2018. The study population included nonpregnant women 20 years of age or older, who had available data on the oral health examination and age at first birth (AFB). Dental caries experience was defined as the DMFT score (sum of the number of decayed, missing due to caries, and filled permanent teeth). The associations between AFB and DMFT scores were assessed using Poisson regression to compute incidence rate ratios (IRRs) and the associated 95% confidence intervals (CIs). Results: This study included 6,553 women (mean age 53.4 years, SD 15.7). The mean DMFT index score was 13.1 ± 7.4, with younger AFB groups generally having higher mean scores. After adjusting for sociodemographic variables, time since last dental visit, and reproductive health factors, women with an AFB of <18 years (IRR, 1.10; 95% CI, 1.01-1.21) or 18-20 years (IRR, 1.11; 95% CI, 1.01-1.21) had significantly higher DMFT index scores compared to those with an AFB of 30-32 years. Conclusions: This study suggests that younger maternal AFB may be associated with greater dental caries experience. More rigorous studies are necessary to determine how to improve oral health outcomes during pregnancy and postpartum.

Clinical Effects of Sugar Substitutes on Cariogenic Bacteria: A Systematic Review and Meta-Analysis

BACKGROUND

The use of sugar substitutes in food products has recently increased. Limited information regarding the role of various sugar substitutes in caries prevention was found. This systematic review and meta-analysis was conducted to investigate the effects of sugar substitute consumption on reducing cariogenic bacteria in dental plaque and saliva.

METHODS

We systematically searched PubMed, EMBASE, and Web of Science (inception to July 2023) for prospective controlled trials published in English and investigated the effects of sugar substitute consumption on cariogenic bacteria in dental plaque and saliva. The primary outcome was the changes in cariogenic bacteria. Two independent reviewers screened the papers. Quality was assessed using the Cochrane risk-of-bias tools.

RESULTS

From 977 studies identified, 32 trials were included. Almost half (14/32, 44%) of the included studies had a high risk of bias. Almost all (31/32, 96.88%) were investigations of xylitol and other sugar alcohols (low-intensity sweeteners), such as sorbitol, erythritol, and maltitol. Only one trial investigated stevia, a high-intensity sweetener, whereas no studies on other high-intensity sweeteners, such as sucralose, saccharin, or aspartame, were found. Almost all studies (30/32, 93.75%) showed the consumption of low-intensity sweeteners led to a significant reduction of different types of cariogenic bacteria. The results of the meta-analysis showed that consumption of low-intensity sweeteners led to a significant reduction of cariogenic bacteria in both dental plaque and saliva compared to no treatment.

CONCLUSION

The consumption of low-intensity sweeteners helps reduce cariogenic bacteria in dental plaque and saliva. There is limited clinical evidence regarding the role of high-intensity sweeteners in reducing cariogenic bacteria.

Incorporating nanosilver with glass ionomer cement-A literature review

OBJECTIVES

The objectives of this study were to retrieve and review studies that incorporated nanosilver with GIC and summarise the evidence regarding the properties of nanosilver-modified GIC.

MATERIALS AND METHODS

Two independent researchers performed a literature search using the keywords (nanosilver OR nano-silver OR (nano silver) OR (silver nanoparticles)) AND (GIC OR (glass ionomer cement) OR (glass ionomer cements)) in PubMed, Web of Science and ScienceDirect.

RESULTS

A total of 368 articles were identified. After removing duplicate results, titles and abstracts were screened for eligibility. Full texts of publications that investigated the manufacture and properties of nanosilver-modified GIC were retrieved and analysed. Finally, 21 studies were included.

CONCLUSIONS

All of the studies reviewed in this investigation included the incorporation of nanosilver in GIC. The proportions of nanosilver added into GIC varied from 0.05 % to 50 %. Thirteen studies investigated the antimicrobial properties of nanosilver-modified GIC; all studies supported that adding nanosilver enhanced antimicrobial effectiveness. Nineteen studies reported the mechanical properties including compressive strength, flexure strength, tensile strength, and microhardness of nanosilver-modified GIC; but the results were inconclusive. Four studies tested the bonding strength of nanosilver-modified GIC to dentine and found that adding nanosilver would not influence the bonding property of GIC. Some studies explored fluoride release level, colour stability, and cytotoxicity of nanosilver-modified GIC; but the results were all inconclusive.

CLINICAL SIGNIFICANCE

This literature review is the first study to retrieve and summarise the findings and evidence regarding nanosilver-modified GIC research. It can provide clinicians with clinically relevant information about novel GIC materials that can be used in their treatment decisions.

Decomposing Socioeconomic Inequality in Early Childhood Caries Among 3 to 5-Year-Old Children in China

INTRODUCTION AND AIMS

Early childhood caries (ECC) is a widespread oral disease that harms children's health in China. Although previous studies have linked ECC prevalence to socioeconomic status, few have measured the degree of socioeconomic inequality. This study aimed to evaluate the socioeconomic inequality of ECC in children aged 3 to 5 years in China and identify the contributor to the inequality.

METHODS

We extracted data on 3 to 5-year-old children from the fourth National Oral Health Survey. We measured the inequality of ECC by the average household income per capita. We used the average household income per capita to measure the inequality of ECC. To describe inequality both qualitatively and quantitatively, we used the following methods: concentration curve, Erreygers-corrected concentration index, relative index of inequality and slope index of inequality. We also applied a decomposition based on the probit model to identify the factors that contributed to inequality.

RESULTS

The prevalence of ECC in Chinese preschool children was 63.11% (95% CIs: 60.54%, 65.61%). The negative value of the Erreygers-corrected concentration index (-0.0459; 95% CIs: -0.0594, -0.0324), slope index of inequality (-0.0674; 95% CIs: -0.0876, -0.0471) and the positive value of relative index of inequality (0.7484; 95% CIs: 0.6856, 0.8169) all indicated that ECC prevalence was higher among children from low-income families. The main factors contributing to inequality were average household income, parents' educational level and living areas.

CONCLUSION

There is a pro-poor inequality in ECC among 3 to 5-year-old children in China.

CLINICAL RELEVANCE

To improve oral health equality, policymakers should focus more on children from low-income families, with less educated parents and living in rural areas.

Novel strategy of S. mutans gcrR gene over-expression plus antibacterial dimethylaminohexadecyl methacrylate suppresses biofilm acids and reduces dental caries in rats

OBJECTIVE

Streptococcus mutans (S. mutans) is a major contributor to dental caries, with its ability to synthesize extracellular polysaccharides (EPS) and biofilms. The gcrR gene is a regulator of EPS synthesis and biofilm formation. The objectives of this study were to investigate a novel strategy of combining gcrR gene over-expression with dimethylaminohexadecyl methacrylate (DMAHDM), and to determine their in vivo efficacy in reducing caries in rats for the first time.

METHODS

Two types of S. mutans were tested: Parent S. mutans; and gcrR gene over-expressed S. mutans (gcrR OE S. mutans). Bacterial minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) were measured with DMAHDM and chlorhexidine (CHX). Biofilm biomass, polysaccharide, lactic acid production, live/dead staining, colony-forming units (CFUs), and metabolic activity (MTT) were evaluated. A Sprague-Dawley rat model was used with parent S. mutans and gcrR OE S. mutans colonization to determine caries-inhibition in vivo.

RESULTS

Drug-susceptibility of gcrR OE S. mutans to DMAHDM or CHX was 2-fold higher than that of parent S. mutans. DMAHDM reduced biofilm CFU by 3-4 logs. Importantly, the combined gcrR OE S. mutans+ DMAHDM dual strategy reduced biofilm CFU by 5 logs. In the rat model, the parent S. mutans group had a higher cariogenicity in dentinal (Dm) and extensive dentinal (Dx) regions. The DMAHDM + gcrR OE group reduced the Dm and Dx caries to only 20 % and 0 %, those of parent S. mutans + PBS control group (p < 0.05). The total caries severity of gcrR OE + DMAHDM group was decreased to 51 % that of parent S. mutans control (p < 0.05).

SIGNIFICANCE

The strategy of combining S. mutans gcrR over-expression with antibacterial monomer reducing biofilm acids by 97 %, and reduced in vivo total caries in rats by 48 %. The gcrR over-expression + DMAHDM strategy is promising for a wide range of dental applications to inhibit caries and protect tooth structures.

Evaluation of incipient enamel-carious-like lesion treated with hydroxyapatite-chitosan nanocomposite hydrogel

BACKGROUND

Non-invasive restoration of tooth enamel is a topic of high relevance in dental material science. Multiple approaches have been proposed to reach optimum reconstruction results. The current study was performed to evaluate the cross-sectional microhardness besides mineral quality and content in artificially induced carious enamel after treatment with hydroxyapatite-chitosan (HAp-CS) nanocomposite gel.

METHODS

Artificially carious lesions were induced by immersion of teeth in acidic carboxymethyl cellulose gel (pH 4.95-5) for 24- and 72-hours periods. Two different compositions of HAp-CS nanocomposite hydrogel were prepared with two different ratios 50/50 (%) and 70/30 (%), respectively. Additionally, sodium fluoride gel (1000 ppm concentration) was prepared and used as reference. Gels were applied to carious lesions twice/day for 3 min/each. After 45 days of application, surface morphology, energy dispersive x-ray spectroscopy, micro-Raman analysis in addition to cross-sectional microhardness were evaluated. Statistical analysis was performed using two-way ANOVA and Tukey's post hoc statistical tests.

RESULTS

Surface morphological evaluation of treated surfaces showed obliteration of surface irregularities. Groups demineralized for 24 hours and treated with 70/30 (HAp-CS) showed highest significant cross-sectional-microhardness (P ≤ 0.05). Evaluated subsurface cross-sectional microhardness showed better mineral quality for groups demineralized for 24 hours and treated with HAp-CS nanocomposite gels.

CONCLUSIONS

Nanocomposite gel with 70/30 (HAp-CS) could efficiently improve cross-sectional microhardness and both minerals composition and quality for lesions demineralized for 24 hours. More severely induced lesions, as demineralized for 72 hours, need more powerful agent compositions and/or prolonged application protocols for improvement.

Association Between ABO Blood Group, Dental Caries, Gingivitis, Impacted Teeth and Malocclusion Among Saudi Adults: A Cross-Sectional Study

Background

Whether there is a relationship between blood group and the likelihood of acquiring oral diseases. Therefore, the present study investigated the potential association between ABO blood groups and various dental conditions, including dental caries, gingivitis, malocclusion, and impacted teeth, in Saudi adults aged 18 years and older.

Methods

A cross-sectional study was conducted on 300 participants who met the inclusion criteria. Data collection included assessment of dental caries status using the decayed missing filled teeth (DMFT) and decayed missing filled surfaces (DMFS) indices, evaluation of gingivitis using the Gingival Index, classification of malocclusion according to Angle's classification system, and recording the presence or absence of impacted teeth.

Results

The AB blood group had the significantly highest mean DMFS score (8.58±6.63), while the O blood group had the lowest mean DMFS score (6.37±4.43). Additionally, blood group O showed a slightly higher prevalence of gingivitis (51.92%) than the other blood groups. Blood group A demonstrated a higher prevalence of both Class II (34.2%) and Class III (19%) malocclusions, with statistically significant differences. Regarding impacted teeth, blood group AB (48.8%) had the highest occurrence.

Conclusion

There exists an association between oral disease and ABO blood group in Saudi adults. The results of this study indicate that individuals with specific blood types may be more prone to oral diseases, which can aid in the early diagnosis and prevention of these conditions.

Effects of a Novel Magnetic Nanomaterial on Oral Biofilms

Dental caries is one of the most common oral chronic infectious diseases, and novel antibacterial materials must be developed to control plaque and inhibit formation of dental caries. Combining magnetic nanomaterials with antibacterial agents to decrease the formation of bacterial biofilm has been a hot topic in the biomedical field. The present study developed a novel magnetic nanomaterial chemically combined with dimethylaminododecyl methacrylate (DMADDM) and initially investigated its inhibiting effects on biofilms by using traditional caries-related bacteria and saliva flora models. The novel magnetic nanomaterials successfully loaded DMADDM according to thermogravimetric analysis, Fourier transform infrared spectroscopy, x-ray diffraction, vibrating sample magnetometry, scanning electron microscopy, and transmission electron microscopy results. Further, the novel nanoparticle Fe3O4@SiO2@DMADDM with concentration of 8 mg/mL could effectively reduce Streptococcus mutans biofilm and decrease the production of lactic acid. The 16S rDNA sequencing revealed that Fe3O4@SiO2@DMADDM could depress the proportion of caries-related bacteria in saliva-derived biofilm, such as Streptococcus, Veillonella, and Neisseria. Therefore, Fe3O4@SiO2@DMADDM is a novel effective antibacterial magnetic nanomaterial and has clinical potential in plaque control and dental caries prevention.

Antimicrobial peptide-based strategies to overcome antimicrobial resistance

Antibiotic resistance has emerged as a global threat, rendering the existing conventional treatment strategies ineffective. In view of this, antimicrobial peptides (AMPs) have proven to be potent alternative therapeutic interventions with a wide range of applications in clinical health. AMPs are small peptides produced naturally as a part of the innate immune responses against a broad range of bacterial, fungal and viral pathogens. AMPs present a myriad of advantages over traditional antibiotics, including their ability to target multiple sites, reduced susceptibility to resistance development, and high efficacy at low doses. These peptides have demonstrated notable potential in inhibiting microbes resistant to traditional antibiotics, including the notorious ESKAPE pathogens, recognized as the primary culprits behind nosocomial infections. AMPs, with their multifaceted benefits, emerge as promising candidates in the ongoing efforts to combat the escalating challenges posed by antibiotic resistance. This in-depth review provides a detailed discussion on AMPs, encompassing their classification, mechanism of action, and diverse clinical applications. Focus has been laid on combating newly emerging drug-resistant organisms, emphasizing the significance of AMPs in mitigating this pressing challenge. The review also illuminates potential future strategies that may be implemented to improve AMP efficacy, such as structural modifications and using AMPs in combination with antibiotics and matrix-inhibiting compounds.

Research Interest in Copper Materials for Caries Management: A Bibliometric Analysis

This study examined research interest in copper materials for caries management. We conducted an exhaustive literature search of English publications on copper materials for caries management. We removed duplicate publications and screened the titles and abstracts to identify relevant publications. Then, we analyzed the bibliometric data of the publications using the Bibliometrix and VOSviewer programs. This study included 75 laboratory studies, six clinical trials, and 17 reviews. Most of the original research studied copper or copper oxide nanoparticles (45/81, 56%). The materials could be doped into topical agents, restorative fillers, dental adhesives, dental implants, and orthodontic appliances. Since the first paper was published in 1980, publication counts gradually increased and surged in 2019. Among publications on copper materials for caries management, the publication counts and citations from 2019 to 2024 accounted for 65% (64/98) and 74% (1677/2255) over the last 45 years. Cocitation analysis revealed that the two main keywords were nanoparticles and antibacterial activity, and their burst strengths (period) were 3.84 (2021-2024) and 2.21 (2020-2021). The topics of the top two publications with the highest citation burst strength (period) are the antimicrobial effect of copper oxide nanoparticles (3.14, 2021-2022) and the dental application of copper nanoparticles (2.84, 2022-2024). In conclusion, this study revealed a growing interest in copper materials for caries management.

The Use of Artificial Intelligence in Caries Detection: A Review

Advancements in artificial intelligence (AI) have significantly impacted the field of dentistry, particularly in diagnostic imaging for caries detection. This review critically examines the current state of AI applications in caries detection, focusing on the performance and accuracy of various AI techniques. We evaluated 40 studies from the past 23 years, carefully selected for their relevance and quality. Our analysis highlights the potential of AI, especially convolutional neural networks (CNNs), to improve diagnostic accuracy and efficiency in detecting dental caries. The findings underscore the transformative potential of AI in clinical dental practice.

Depression, stress-related disorders and risk for dental caries and periodontitis: A bidirectional and multivariable Mendelian randomization study

AIMS

Our Mendelian randomization (MR) analysis focused on investigating the bidirectional relationships between major depressive disorder (MDD), anxiety and stress-related disorder (ASRD), and dental caries as well as periodontitis.

MATERIALS AND METHODS

We used summary statistics from two studies: an MDD genome-wide association study (GWAS) including 135,458 cases with 344,901 controls and a Lundbeck Foundation Initiative for Integrative Psychiatric Research (iPSYCH) GWAS based on 12,655 ASRD individuals and 19,225 controls from Denmark. GWASs on dental caries and periodontitis were based on the Gene-Lifestyle Interactions in Dental Endpoints (GLIDE) consortium. We employed different MR approaches, such as inverse-variance weighted (IVW), MR-Egger, weighted median, and MR-PRESSO, to calculate causal effects.

RESULTS

Single-variable MR analysis revealed that ASRD was potentially significantly associated with decayed, missing, and filled tooth surfaces (DMFS) (β = 0.056; 95 % CI: 0.009, 0.103; p = 0.018). Periodontitis was suggested to be causally related to increased ASRD risk (OR = 1.143, 95 % CI: 1.008, 1.298; p = 0.038). According to the multivariable MR analysis, no significant associations were detected between MDD and ASRD with dental caries and periodontitis, and vice versa.

CONCLUSIONS

ASRD demonstrated a potential association with DMFS, and periodontitis was found to potentially impact ASRD according to single-variable MR analysis. Nevertheless, no significant associations were identified between MDD, ASRD, dental caries, or periodontitis after adjusting for smoking status and education level. Hence, more robust genetic instruments are required to validate and reinforce our findings.

Prevalence of dental carries among school-going children aged 7-13 years in Kabul City

BACKGROUND

Dental caries is a major, multifactorial oral condition that causes the demineralization of tooth enamel and impacts approximately half of the world's child population. This study aimed to determine the prevalence of dental caries among school-going children aged 7 to 13 years in Kabul city.

METHODS

This descriptive cross-sectional study was conducted with 491 students aged 7 to 13 years in Kabul during the first half of 2019. A multistage cluster sampling method was used, in which educational zones, schools, and classes were selected. The data were collected using pre-structured questionnaires through face-to-face interviews and oral examinations of students using dental probes and mouth mirrors while adhering to infection control protocols. The collected data were analyzed using Statistical Package for Social Science version 21.0, and a p-value < 0.005 was considered as statistically significant.

RESULTS

The average age of the study participants was 9.9 ± 1.8 years. Boys made up approximately 45% of the participants, while 54.8% were girls. The overall prevalence of dental caries was 78.8%, with 62.1% in deciduous teeth and 42.8% in permanent teeth. Among students who did not brush their teeth, the prevalence of dental caries was 84.8%, compared to 81.7% for those who brushed once daily, 78.7% for those brushing twice daily, and 67.4% for those brushing three times daily (p = 0.022). About 10% of students had dental calculus, with a prevalence of 17.0% among those aged eleven and older, 10.0% among students aged nine to ten years, and 5.9% among students aged eight and younger (p = 0.006). Poor oral hygiene affected nearly one-third of the students, with 34.2% among boys and 30.9% among girls. Poor oral hygiene was more prevalent in students aged eight and younger (38.8%) compared to those aged eleven and older (25.9%) (p = 0.023).

CONCLUSIONS

The prevalence of dental caries among students aged 7 to 13 years in Kabul schools was similar to that in most developing countries. The prevalence of dental calculus was greater among students aged eleven years and older. Over 99% of the students surveyed had not undergone any dental treatment.

Comparison of various chitosan-based in situ forming gels with sodium fluoride varnish for enamel biomineralization: an in-vitro pH cycling model

This study aimed to evaluate chitosan (CS)-based formulations loaded with 5% sodium fluoride (NaF) and/or 10% nanohydroxyapatite (nHA) to remineralize the demineralized primary tooth enamel surface. Ninety enamel blocks were demineralized and were divided into six groups (n = 15): (1) CS-based hydrogel, (2) CS-based hydrogel loaded with NaF, (3) CS-based hydrogel loaded with nHA, (4) CS-based hydrogel loaded with NaF and nHA, (5) 5% NaF varnish, and (6) negative control with no intervention. After intervention, the specimens were pH cycled by 2 h immersion in demineralizing solution and 22 h immersion in remineralizing solution for 8 days. The remineralization effects were evaluated by Vickers microhardness measurements and field emission scanning electron microscopy coupled with energy-dispersive X-ray spectrometry (FESEM-EDS). The best mean ± SD percentage microhardness recovery in remineralized enamel (%REMH) was found in group 4 (56.90 ± 5.49). The %REMH of groups 2 (30.74 ± 3.51) and 5 (29.23 ± 5.65) were statistically the same (p = 0.943). FESEM images confirmed partial coverage of the porous demineralized enamel with a newly formed mineralized layer. Based on EDS findings, the Ca/P ratio values of the treated enamel surfaces with CS-based hydrogels ranged between 1.71 and 1.87, and the highest F content was noticed in group 2 (1.02 ± 0.03). Although, all tested CS-based hydrogels demonstrated the potential to repair demineralized enamel, nHA- and NaF-containing CS-based hydrogel showed the highest remineralization effect. We infer that this new hybrid hydrogel is a potentially useful dental material for tooth biomineralization.