Ion release of the glass ionomer restoration with silver diamine fluoride dentin pretreatment.

OBJECTIVE: To assess the fluoride and silver ion release of glass ionomer cement (GIC) restorations, including conventional GIC (CGIC) and resin-modified GIC (RMGIC) restorations, with 38% silver diamine fluoride (SDF) solution dentin pretreatment. METHODS: Eighty dentin blocks were allocated into 4 groups and restored with SDF+CGIC, CGIC, SDF+RMGIC and RMGIC, respectively. Each block was stored in deionized water at 37°C for 2 years. Fluoride and silver ion concentration in storage solution was measured using ion-selective electrode and inductively coupled plasma-optical emission spectrometry for up to 2 years. The cross-sectional surfaces of restored dentin blocks were assessed by X-Ray diffraction analysis (XRD), scanning electron microscope (SEM) with energy-dispersive X-ray spectroscopy (EDS) after 1 week and 2 years, respectively. RESULTS: The mean ± standard deviation (SD) of accumulative fluoride releasing in SDF+CGIC, CGIC, SDF+RMGIC and RMGIC for 2 years were 0.13±0.005 mg, 0.09±0.006 mg, 0.15±0.008 mg and 0.05±0.003 mg, respectively (Groups SDF+RMGIC > SDF+CGIC > CGIC >RMGIC, p<0.05). The mean ± SD of accumulative silver releasing in SDF+CGIC, CGIC, SDF+RMGIC and RMGIC for 2 years were 0.03±0.009 mg, 0.00±0.00 mg, 0.01±0.003 mg, and 0.00±0.00 mg, respectively (Groups SDF+CGIC > SDF+RMGIC > CGIC&RMGIC, p<0.05). Groups SDF+CGIC and SDF+RMGIC showed sustainably higher fluoride and silver releasing compared to Groups CGIC and RMGIC (p<0.05). XRD analysis indicated the fluorapatite and silver chloride were observed only in Groups SDF+CGIC and SDF+RMGIC, but not in Groups CGIC and RMGIC. SEM images of the cross-sectional view of the dentin blocks showed silver crystals within dentinal tubules 1 week and 2-year in Groups with SDF pretreatment. CONCLUSION: The 38% SDF dentin pretreatment sustainably increased the fluoride and silver release of GIC and RMGIC restorations for up to 2 years.

Developing a novel glass ionomer cement with enhanced mechanical and chemical properties.

OBJECTIVE: To develop a novel glass ionomer cement (NGIC) with enhanced mechanical and chemical properties and assess its biocompatibility, mechanical strength, and ion release. METHODS: Nanosilver doped bioactive glass (NanoAg BAG) was synthesized by sol-gel method and characterized by scanning electron microscopy with energy-dispersive X-ray spectroscopy and transmission electron microscopy. The NanoAg BAG, together with poly(vinylphosphonic acid) (PVPA), alumino-fluorosilicate glass and poly-acrylic acid were used to synthesize NGIC. The optimal PVPA concentration for NGIC was determined by PVPA modified GIC's biocompatibility and mechanical properties and used to prepare NGIC specimens. NGIC specimens with NanoAg BAG at 0%, 1%, 2%, and 5% were allocated into Groups NGIC0, NGIC1, NGIC2, and NGIC5, respectively. The biocompatibility, surface morphology, elemental composition, surface topography, chemical properties, compressive strength, diametral tensile strength, and ion release of the NGIC were assessed. A conventional glass ionomer cement (GIC) was used as a control. RESULTS: A granular BAG with nano silver particles attached on its surface were found, indicating the successful synthesis of NanoAg BAG. PVPA at 10% presented the best effect in enhancing the biocompatibility and mechanical properties of PVPA modified GIC and was used to prepare NGIC specimens. NGIC1 showed similar biocompatibility, surface morphology and topography to GIC. Chemical properties results showed that NGICs showed the same adsorption peaks to GIC. The compressive strength (mean±SD in MPa) was 168.1 ± 29.7, 205.5 ± 29.5, 221.8 ± 46.8, 216.6 ± 59.3 and 167.7 ± 36.4, and the diametral tensile strength (mean±SD in MPa) was 14.1 ± 1.7, 18.3 ± 4.9, 21.2 ± 2.2, 17.2 ± 3.8 and 13.3 ± 3.3 for GIC, NGIC0, NGIC1, NGIC2 and NGIC5 respectively. NIGC0, NGIC1 and NGIC2 showed higher compressive and diametral tensile strength than GIC (p < 0.01). NGIC2 and NGIC5 showed higher release of fluoride, calcium, phosphate and silver ion than GIC and NGIC0 (p < 0.05). CONCLUSION: A biocompatible NGIC with enhanced mechanical properties were developed. It presented enhanced fluoride, calcium, phosphate and silver ion release compared to conventional GIC.

Erosive tooth wear among non-institutionalised older adults in Hong Kong: a cross-sectional study.

BACKGROUND: Non-institutionalised older adults is the majority of older adults in Hong Kong. The study aimed to examine erosive tooth wear (ETW) and its association with dental conditions and oral hygiene habits among non-institutionalised older adults in Hong Kong. METHODS: This cross-sectional study recruited dentate adults aged 60 or above from nine elderly daycare centres in the five main districts of Hong Kong. The study consists of a questionnaire survey and a clinical examination. A researcher used a questionnaire to collected the participants' demographic information, oral hygiene habits such as toothbrushing habits and dental visit behaviour. A calibrated examiner performed an oral examination in the daycare elderly centre to assess the ETW using basic erosive wear (BEWE) criteria. Oral hygiene was recorded using visible plaque index. Prosthetic status was recorded using the World Health Organization criteria. Logistic regression was used to examine the correlation between ETW and the dental conditions and oral hygiene habits. RESULTS: This study recruited 433 dentate adults and 333 adults were female (77%). Their age ranged from 60 to 99 years and their mean age was 74 years (SD = 7). They all had ETW (BEWE > 0). Over half of them (57%) had BEWE score of 3, indicating severe ETW. Analysis showed increasing age (OR = 1.030, p = 0.029) and older adults with untreated dental caries had higher odds (OR = 1.822, p = 0.002) of presenting severe ETW. No other associations were found between the ETW and the factors studied. CONCLUSION: Hong Kong non-institutionalised older adults aged 60 or above had ETW and more than half of them had severe ETW. Increasing age and having untreated dental caries were associated with severe ETW.

Application of omics technologies in cariology research: A critical review with bibliometric analysis.

OBJECTIVES: To review the application of omics technologies in the field of cariology research and provide critical insights into the emerging opportunities and challenges. DATA & SOURCES: Publications on the application of omics technologies in cariology research up to December 2022 were sourced from online databases, including PubMed, Web of Science and Scopus. Two independent reviewers assessed the relevance of the publications to the objective of this review. STUDY SELECTION: Studies that employed omics technologies to investigate dental caries were selected from the initial pool of identified publications. A total of 922 publications with one or more omics technologies adopted were included for comprehensive bibliographic analysis. (Meta)genomics (676/922, 73 %) is the predominant omics technology applied for cariology research in the included studies. Other applied omics technologies are metabolomics (108/922, 12 %), proteomics (105/922, 11 %), and transcriptomics (76/922, 8 %). CONCLUSION: This study identified an emerging trend in the application of multiple omics technologies in cariology research. Omics technologies possess significant potential in developing strategies for the detection, staging evaluation, risk assessment, prevention, and management of dental caries. Despite the numerous challenges that lie ahead, the integration of multi-omics data obtained from individual biological samples, in conjunction with artificial intelligence technology, may offer potential avenues for further exploration in caries research. CLINICAL SIGNIFICANCE: This review presented a comprehensive overview of the application of omics technologies in cariology research and discussed the advantages and challenges of using these methods to detect, assess, predict, prevent, and treat dental caries. It contributes to steering research for improved understanding of dental caries and advancing clinical translation of cariology research outcomes.

Application of Zeolites and Zeolitic Imidazolate Frameworks in Dentistry-A Narrative Review.

Zeolites and zeolitic imidazolate frameworks (ZIFs) are crystalline aluminosilicates with porous structure, which are closely linked with nanomaterials. They are characterized by enhanced ion exchange capacity, physical-chemical stability, thermal stability and biocompatibility, making them a promising material for dental applications. This review aimed to provide an overview of the application of zeolites and ZIFs in dentistry. The common zeolite compounds for dental application include silver zeolite, zinc zeolite, calcium zeolite and strontium zeolite. The common ZIFs for dental application include ZIF-8 and ZIF-67. Zeolites and ZIFs have been employed in various areas of dentistry, such as restorative dentistry, endodontics, prosthodontics, implantology, periodontics, orthodontics and oral surgery. In restorative dentistry, zeolites and ZIFs are used as antimicrobial additives in dental adhesives and restorative materials. In endodontics, zeolites are used in root-end fillings, root canal irritants, root canal sealers and bone matrix scaffolds for peri-apical diseases. In prosthodontics, zeolites can be incorporated into denture bases, tissue conditioners, soft denture liners and dental prostheses. In implantology, zeolites and ZIFs are applied in dental implants, bone graft materials, bone adhesive hydrogels, drug delivery systems and electrospinning. In periodontics, zeolites can be applied as antibacterial agents for deep periodontal pockets, while ZIFs can be embedded in guided tissue regeneration membranes and guided bone regeneration membranes. In orthodontics, zeolites can be applied in orthodontic appliances. Additionally, for oral surgery, zeolites can be used in oral cancer diagnostic marker membranes, maxillofacial prosthesis silicone elastomer and tooth extraction medicines, while ZIFs can be incorporated to osteogenic glue or used as a carrier for antitumour drugs. In summary, zeolites have a broad application in dentistry and are receiving more attention from clinicians and researchers.

Use of Digital Diagnostic Aids for Initial Caries Detection: A Review.

The advance in digital diagnostic technologies has significantly facilitated the detection of dental caries. Despite the increase in clinically available digital diagnostic aids for dental caries, there is yet to be a comprehensive summary of all available technology. This review aims to provide an overview of digital diagnostic aids for the clinical detection of dental caries, particularly those at an initial stage. Currently available digital diagnostic aids for caries detection can be classified into four categories according to the initial source of energy, including radiation-based aids, light-based aids, ultrasound-based aids, and electric-based aids. Radiation-based aids use ionizing radiation, normally X-ray, to produce images of dental structures. Radiation-based aids encompass digital bitewing radiography and cone beam computed tomography. Light-based aids employ light or laser to induce signals for the detection of the changes in the carious dental hard tissue. Common light-based aids include digital transillumination and light/laser-induced fluorescence. Ultrasound-based aids detect the signal of ultrasound waves to assess the acoustic impedance of the carious teeth. The ultrasound caries detector is an available ultrasound-based aid. Electric-based aids assess the changes in the electric current conductance or impedance of the teeth with caries. Available electric-based aids include electrical conductance measurement and alternating current impedance spectroscopy. Except for these clinically available digital diagnostic aids, many digital diagnostic aids for caries detection are still under development with promising results in laboratory settings.

The preventive effect of glass ionomer cement restorations on secondary caries formation: A systematic review and meta-analysis.

OBJECTIVE: The objective is to compare the preventive effect on secondary caries of glass ionomer cement (GIC) restorations with amalgam or resin-composite restorations. METHODS: Two independent researchers conducted a systematic search of English publications in PubMed, Web of Science, Cochrane and Scopus. They selected randomized clinical trials comparing secondary caries incidences around GIC restorations (conventional GIC or resin-modified GIC) with amalgam or resin-composite restorations. Meta-analysis of the secondary-caries incidences with risk ratio (RR) and 95% confidence interval (95% CI) as the effect measure was performed. RESULTS: This review included 64 studies. These studies included 8310 GIC restorations and 5857 amalgam or resin-composite restorations with a follow-up period from 1 to 10 years. Twenty-one studies with 4807 restorations on primary teeth and thirty-eight studies with 4885 restorations on permanent teeth were eligible for meta-analysis. The GIC restorations had a lower secondary caries incidence compared with amalgam restorations in both primary dentition [RR= 0.55, 95% CI:0.41-0.72] and permanent dentition [RR= 0.20, 95% CI:0.11-0.38]. GIC restorations showed similar secondary caries incidence compared with resin-composite restorations in primary dentition [RR= 0.92, 95% CI:0.77-1.10] and permanent dentition [RR= 0.77, 95% CI:0.39-1.51]. Conventional GIC restorations showed similar secondary caries incidence compared with resin-modified GIC-restored teeth in both primary dentition [RR= 1.12, 95% CI:0.67-1.87] and permanent dentition [RR= 1.63, 95% CI:0.34-7.84]. CONCLUSIONS: GIC restorations showed a superior preventive effect against secondary caries compared to amalgam restorations, and a similar preventive effect against secondary caries compared to resin-composite restorations in both primary and permanent teeth. [PROSPERO Registration ID: CRD42022380959].

A concise review of chewing gum as an anti-cariogenic agent.

Chewing gum has been endorsed as a caries preventive agent by the FDI World Dental Federation, the American Dental Association, and the European Food Safety Authority. This review discusses the mechanism and provides an update of the use of chewing gum for caries prevention. Chewing gum typically consists of a water-insoluble gum base, water-soluble added ingredients, and active ingredients. It can be classified as sugar-containing or sugar-free, as well as nonmedicated or medicated. Chewing gum prevents dental caries through a range of mechanisms, including the clearance of the oral cavity, neutralization of oral acidity, inhibition of cariogenic bacterial growth, remineralization of enamel, and reduction of appetite. Recent clinical studies have evaluated the efficacy of sugar-free chewing gum for caries prevention, with most demonstrating positive results, although some studies have reported contradictory outcomes. To achieve optimal caries prevention, it is generally recommended that individuals chew sugar-free gum for five minutes after meals, three times daily.

Dental Pulp Response to Silver-Containing Solutions: A Scoping Review.

Dentists used silver-containing solutions for deep cavity disinfection before restoration. This review aims to identify the silver-containing solutions reported in the literature for deep cavity disinfection and summarize their effects on dental pulp. An extensive search was performed using the search words "(silver) AND (dental pulp OR pulp)" in ProQuest, PubMed, SCOPUS, and Web of Science to identify English publications on silver-containing solutions for cavity conditioning. The pulpal response to the included silver-containing solutions was summarized. The initial search identified 4112 publications and 14 publications met the inclusion criteria. Silver fluoride, silver nitrate, silver diamine nitrate, silver diamine fluoride, and nano-silver fluoride were used in deep cavities for antimicrobial purposes. Indirect silver fluoride application induced pulp inflammation and reparative dentine in most cases, and pulp necrosis in some cases. Direct silver nitrate application caused blood clots and a wide inflammatory band in the pulp, whilst indirect silver nitrate application caused hypoplasia in shallow cavities and partial pulp necrosis in deep cavities. Direct silver diamine fluoride application induced pulp necrosis, while indirect silver diamine fluoride application induced a mild inflammatory response and reparative dentine formation. No evidence of the dental pulpal response to silver diamine nitrate or nano-silver fluoride was available in the literature.

Effect of silver diamine fluoride upon the microbial community of carious lesions: A scoping review.

OBJECTIVES: To explore the effects of silver diamine fluoride (SDF) on the microbial community of carious lesions. DATA: Original studies evaluating the effect of SDF treatment on the microbial community of human carious lesions were included. SOURCES: A systematic search of English-language publications was performed in PubMed, EMBASE, Scopus, and Web of Science. Gray literature was searched in ClinicalTrials.gov and Google Scholar. STUDY SELECTION/RESULTS: This review included seven publications reporting the effects of SDF on microbial community of dental plaque or carious dentin, including the microbial biodiversity, relative abundance of microbial taxa, and predicted functional pathways of the microbial community. The studies on microbial community of dental plaque reported that SDF did not have a significant effect on both the within-community species diversity (alpha-diversity) and inter-community microbial compositional dissimilarity (beta-diversity) of the plaque microbial communities. However, SDF changed the relative abundance of 29 bacterial species of plaque community, inhibited carbohydrate transportation and interfered with the metabolic functions of the plaque microbial community. A study on the microbial community in dentin carious lesions reported that SDF affected its beta-diversity and changed the relative abundance of 14 bacterial species. CONCLUSION: SDF showed no significant effects on the biodiversity of the plaque microbial community but changed the beta-diversity of the carious dentin microbial community. SDF could change the relative abundance of certain bacterial species in the dental plaque and the carious dentin. SDF could also affect the predicted functional pathways of the microbial community. CLINICAL SIGNIFICANCE: This review provided comprehensive evidence on the potential effect of SDF treatment on the microbial community of carious lesions.

A concise review of dental sealants in caries management.

This concise review provides an update of the use of dental sealants. Dental sealants protect a tooth from caries development by providing a physical barrier to microorganism colonisation and creating a favorable environment for patients to clean. Some sealants release fluoride ions to promote remineralization. Dental sealants can be applied on pits and fissures of primary and permanent teeth to prevent and arrest early enamel caries. They are effective in caries prevention. The preventive fraction of resin sealant is up to 61% after 5 years. Dental sealants can be classified as resin, glass ionomer and hybrid (compomer or giomer) according to the material. Recent studies from 2012 to 2022 showed resin sealant has a high retention rate of up to 80% after 2 years, whereas glass ionomer sealants is 44%. Chemical etching with 37% phosphoric acid is the standard of care, whereas laser or air-abrasion cannot does not increase the sealant retention rate. Moist control is critical and studies found the use of rubber dam and cotton rolls had similar success for sealant retention. The longevity of dental sealant is also associated with clinical operative factors, including approaches of moisture control, enamel pretreatment, selection of dental adhesive, and time of acid etching.

A novel glass ionomer cement with silver zeolite for restorative dentistry.

OBJECTIVE: To develop an antimicrobial silver zeolite glass ionomer cement (SZ-GIC) and determine its biocompatibility, physical, adhesive and antibacterial properties. METHODS: Silver nitrate and sodium zeolite were used to synthesize silver zeolite (SZ). SZ-GICs were prepared by incorporating SZ into GIC at 5% (SZ-GIC5), 2% (SZ-GIC2), or 1% (SZ-GIC1) by weight, respectively. The SZ-GICs were characterized by evaluating surface morphology, topography and elemental composition. SZ-GICs' biocompatibility was assessed by evaluating cell cytotoxicity. Their physical properties were determined by testing setting time, compressive strength, flexural strength, water sorption and solubility. Their adhesive property was assessed by evaluating micro-tensile bond strength. Their antibacterial properties were assessed by evaluating biofilm growth kinetic, metabolic activity, viability and morphology. GIC was used as a control. RESULTS: SZ was a three-dimensional crystalline mineral. SZ-GICs (including SZ-GIC 5, 2 and 1) showed similar surface morphology and topography to GIC. SZ-GIC1 and GIC had no difference in cell cytotoxicity (p>0.05). SZ-GICs and GIC showed no difference in setting time (p>0.05). SZ-GICs had higher compressive and flexural strength than GIC (p<0.05). SZ-GIC2 and SZ-GIC1 showed lower water sorption and solubility than GIC (p<0.05). SZ-GICs had higher micro-tensile bond strength than GIC (p<0.05). Biofilms on SZ-GICs' surfaces showed lower colony-forming units, decreased metabolic activities, higher percentages of dead cells and more ruptured bacterial cells compared with those on GIC. CONCLUSION: SZ-GIC with silver zeolite at 1% by weight are as biocompatible as conventional GIC. The SZ-GICs have enhanced physical, adhesive and antibacterial properties than GIC. CLINICAL SIGNIFICANCE: A silver zeolite glass ionomer cement was developed. The SZ-GICs have great potential for caries prevention and management.

Research progress on neutrophil extracellular traps in oral infectious diseases / 口腔疾病防治

@#Eutrophils are the first innate immune cells to reach the site of inflammation. Neutrophils produce neutrophil extracellular traps (NETs) that can quickly capture and limit the spread of pathogens, facilitating the removal of pathogens and their debris. Neutrophils in the oral cavity are specifically transformed from circulating neutrophils in the blood, and the number of NETs released by oral neutrophils is much higher than that of circulating neutrophils, thus better maintaining the balance of the oral microenvironment. As a bimorphic fungus, only the mycelium phase of Candida albicans can induce NETs, which is related to the neutrophils' ability to sense the size of pathogenic microorganisms through neutrophil elastase. However, spherical Staphylococcus aureus are much smaller than Candida albicans, and they can still induce NETs. Porphyromonas gingivalis, as one of the microorganisms in the periodontitis complex, induces fewer NETs than Streptococcus oralis and Actinomycetes, which are two common oral microorganisms, and there may be a mechanism allowing them to escape neutrophilic immunity in the early stage of periodontitis. Although the two main pathways of NET production have been studied in detail, the mechanisms involved in the induction of NETs by different microorganisms, especially from oral neutrophils, are not well understood. This review describes the mechanism of the immune effects of pathogenic microorganisms on neutrophil NETs in the oral cavity, providing a reference for the search for therapeutic targets and the development of key drugs for treating oral infectious diseases.

Copper Materials for Caries Management: A Scoping Review.

This study comprehensively reviewed the types, properties and potential applications of copper materials for caries management. Two researchers independently searched English publications using PubMed, Scopus and Web of Science. They screened the titles and abstracts of publications presenting original studies for review. They included 34 publications on copper materials, which were categorized as copper and copper alloy materials (13/34, 38%), copper salt materials (13/34, 38%) and copper oxide materials (8/34, 24%). All reported copper materials inhibited the growth of cariogenic bacteria such as Streptococcus mutans and Candida albicans. The materials could be doped into topical agents, restorative fillers, dental adhesives, drinking water, dental implants, orthodontic appliances, mouthwash and sugar. Most publications (29/34, 83%) were laboratory studies, five (5/34, 14%) were animal studies and only one paper (1/34, 3%) was clinical research. In conclusion, copper and copper alloy materials, copper salt materials and copper oxide materials have an antimicrobial property that inhibits cariogenic bacteria and Candida albicans. These copper materials may be incorporated into dental materials and even drinking water and sugar for caries prevention. Most publications are laboratory studies. Further clinical studies are essential to validate the effectiveness of copper materials in caries prevention.

Update on Dental Luting Materials.

A dental luting material aids in the retention and stability of indirect restorations on the prepared tooth structure. In dentistry, clinicians are using a wide range of luting materials for the cementation of indirect restorations. Zinc oxide eugenol and non-eugenol cements, zinc phosphate cement, zinc polycarboxylate cement, glass ionomer cement and resin cements are common dental cements used in dentistry. Each luting material or cement possesses unique properties and clinical implications. An ideal luting cement should be biocompatible, insoluble, resistant to thermal and chemical assaults, antibacterial, aesthetic, simple and easy to use. It should have high strength properties under tension, shear and compression to resist stress at the restoration-tooth interface, as well as adequate working and setting times. So far, no luting material possesses all of these properties of an ideal cement. Scientists have been modifying the conventional luting cements to improve the material's clinical performance and developing novel materials for clinical use. To achieve the best clinical outcome, clinicians should update their knowledge and gain a good understanding of the luting materials so that they can make a wise clinical decision on the material selection and obtain an insight into the development of luting cements. Therefore, the objective of this study is to provide a discussion on the physical, chemical, adhesive and aesthetic properties of common luting materials. The clinical indications of these luting materials are suggested based on their properties. In addition, overviews of the modification of the conventional luting materials and the newly developed luting materials are provided.

Principals' Perspectives on Joining a Kindergarten Outreach Dental Service: A Qualitative Study.

In this qualitative study, the researchers explored principals' perspectives on a free outreach dental service with silver diamine fluoride (SDF) therapy for children in kindergarten. Two researchers recruited kindergarten principals using purposive sampling. They conducted individual semi-structured interviews to collect the principals' perspectives regarding their adoption of and experience with the service. They manually transcribed the interview verbatim into text and followed a thematic approach for data analysis. The researchers interviewed eight principals. The principals identified the prevalent caries status and importance of oral health promotion for kindergarten children. They acknowledged that the service enhanced dental knowledge, fostered oral hygiene practice and improved children's oral health. To adopt this service, they needed to ensure adequate capacity to perform the service. They had no concern with staining by SDF because the parents were informed and consented to the SDF therapy. They appreciated the free service provided by a professional team managed by a reputable university. In conclusion, the principals were generally satisfied with the outreach dental service. They realised the necessity of oral health promotion. They found that parents accepted the SDF therapy although the SDF stained their children's carious teeth. They needed support from their teachers and the children's parents to run the service.

Oral Microbiome and Dental Caries Development.

Dental caries remains the most prevalent oral disease worldwide. The development of dental caries is highly associated with the microbiota in the oral cavity. Microbiological research of dental caries has been conducted for over a century, with conventional culture-based methods and targeted molecular methods being used in order to identify the microorganisms related to dental caries. These methods' major limitation is that they can identify only part of the culturable microorganisms in the oral cavity. Introducing sequencing-based technology and bioinformatics analysis has boosted oral microbiome research and greatly expanded the understanding of complex oral microbiology. With the continuing revolution of molecular technologies and the accumulated sequence data of the oral microbiome, researchers have realized that microbial composition alone may be insufficient to uncover the relationship between caries and the microbiome. Most updated evidence has coupled metagenomics with transcriptomics and metabolomics techniques in order to comprehensively understand the microbial contribution to dental caries. Therefore, the objective of this article is to give an overview of the research of the oral microbiome and the development of dental caries. This article reviews the classical concepts of the microbiological aspect of dental caries and updates the knowledge of caries microbiology with the results of current studies on the oral microbiome. This paper also provides an update on the caries etiological theory, the microorganisms related to caries development, and the shifts in the microbiome in dental caries development.

The preventive effect of glass ionomer restorations on new caries formation: A systematic review and meta-analysis.

OBJECTIVE: To investigate the effectiveness of glass ionomer cement (GIC) restorations on preventing new caries in primary or permanent dentitions compared with other types of restorations. DATA: Randomized controlled clinical trials evaluating caries experience increment or caries incidence in patients with GIC restorations, including conventional GIC (CGIC) and resin-modified GIC (RMGIC) restorations, were included. SOURCES: A systematic search of publications in English was conducted in PubMed/Medline, Web of Science, Cochrane, and Scopus databases. STUDY SELECTION/RESULTS: This review included 10 studies reporting caries preventive effect of GIC restorations and selected 5 studies for meta-analysis. Patients with GIC restorations showed lower caries incidence compared with other restorations in primary and permanent dentition [RR=0.67, 95% CI:0.55-0.82, p < 0.0001]. Patients with CGIC restorations showed lower caries incidence compared with amalgam restorations [RR=0.57, 95% CI:0.43-0.76, p = 0.0001] and RMGIC restorations [RR=0.70, 95% CI:0.56-0.87, p = 0.002], but no statistical difference with composite resin restorations [RR=0.73, 95% CI:0.51-1.04, p = 0.08] in primary dentition. Patients with RMGIC restorations showed no statistical differences of caries incidence compared with composite resin restorations in primary and permanent dentition [RR=0.83, 95% CI:0.56-1.22, p = 0.33]. CONCLUSIONS: GIC restorations presented a better preventive effect on new caries than other restorations did in primary and permanent dentitions. CGIC restorations presented a better caries preventive effect on new caries than RMGIC and amalgam restorations in primary dentitions did. RMGIC restorations showed similar preventing effect on new caries with composite resin restorations in primary and permanent dentitions. CLINICAL SIGNIFICANCE: This review affirmed the potential of GIC in preventing new caries development in the dentition.

Knowledge, Practices and Attitudes towards Silver Diamine Fluoride Therapy among Dentists in Japan: A Mixed Methods Study.

In 2021, the World Health Organization included silver diamine fluoride (SDF) as an essential medicine to manage caries in adults and children. SDF was developed in the 1960s, but its use for children became unpopular in Japan because of the decline and low prevalence of early childhood caries. This mixed methods study explored the knowledge, practices and attitudes towards SDF therapy among dentists promoting fluoride use in Japan. It also investigated senior dentists' perceptions of SDF therapy in Japan. The quantitative study invited all 173 members of the largest organisation promoting fluoride use in Japan to complete a web-based questionnaire survey. Sixty (60/173; 35%) dentists promoting fluoride use in Japan completed the questionnaire survey. All dentists knew of SDF treatment, and 50 (50/60; 83%) used SDF for dental care. Fifty-nine dentists (59/60; 98%) agreed that SDF therapy was simple and quick. All 60 dentists agreed that SDF was effective to arrest caries; 51 dentists (51/60; 85%) agreed that SDF was effective to prevent caries. Most dentists (51/60; 85%) were concerned about SDF's unaesthetic staining. Fifty-seven dentists (57/60; 95%) used SDF to arrest primary posterior teeth, and 52 dentists (52/60; 87%) used SDF to arrest root caries. However, 25 dentists (25/60; 42%) did not use SDF to prevent caries in permanent teeth. The qualitative study interviewed 12 senior dentists using snowball sampling and achieved data saturation. The dentists opined that SDF therapy was effective, simple, painless, non-invasive and inexpensive. SDF is seldom used in Japan at present because of the unaesthetic black staining and the low prevalence of early childhood caries; however, it can regain popularity by arresting root caries in the aging population.

Effect of silver diamine fluoride on vital dental pulp: A systematic review.

OBJECTIVE: This study aims to review systematically the dental pulp response to silver diamine fluoride (SDF) treatment, including the inflammatory response, pulp cells activity, dentinogenesis, silver penetration, and the presence of the bacteria in the dental pulp. DATA: In vitro studies, animal studies, clinical studies, and case reports on the use of SDF on vital dental pulp were included. Quality assessment of the included studies was conducted. A narrative synthesis of the collected data was performed. SOURCES: A systematic search was performed in ProQuest, PubMed, SCOPUS, and Web of Science databases for articles published from inception to Nov 1, 2021. STUDY SELECTION: The initial search identified 1,433 publications, of which five publications met the inclusion criteria. These five publications reported the effect of direct/ indirect SDF application on the vital pulp of a total of 30 teeth. Direct SDF application on vital pulp caused pulp necrosis. Indirect SDF application caused none or mild inflammatory response of dental pulp. The odontoblasts in the dental pulp showed increased cellular activity. Tertiary dentine was formed in the pulpal side of the cavity with indirect SDF application. Accentuated incremental lines of tertiary dentine reflected disturbances in mineralisation. Silver ions were found to penetrate along the dentinal tubules but were not detected inside the pulp. CONCLUSION: According to the limited available literature, direct SDF application causes pulp necrosis. Indirect SDF application is generally biocompatible to dental pulp tissue with a mild inflammatory response, increased odontoblastic activity, and increased tertiary dentine formation. Future studies with precise quantitative and qualitative tests, larger sample size and longer follow-up time are imperative to understand the biological activity of dental pulp to SDF treatment.