Hagfish-inspired hydrogel for root caries: A multifunctional approach including immediate protection, antimicrobial phototherapy, and remineralization.

Root caries is the main cause of oral pain and tooth loss in the elderly. Protecting root lesions from environmental disturbances, resisting pathogens, and facilitating remineralization over time are essential for addressing root caries, but are challenging due to the irregular root surface and the complex oral environment. Hagfish secretes slime when facing danger, which converts into gels upon contact with seawater, suffocating the predators. Inspired by hagfish's defense mechanism, a fluid-hydrogel conversion strategy is proposed to establish a mechanical self-regulating multifunctional platform for root caries treatment. The fluid system (silk fibroin-tannic acid-black phosphorene-urea, ST-BP-U), in which urea disrupts the hydrogen bonds between silk fibroin and tannic acid, can easily spread on the irregular root surface and permeate into dentinal tubules. Upon contact with the surrounding water, urea diffuses, prompting the hydrogel re-formation and creating intimate attachments with micromechanical inlay locks. Meanwhile, BP increases the crosslinking of the re-formed hydrogel network, resulting in reinforced cohesion for robust wet adhesion to the tooth root. This process establishes a structured platform for effective antimicrobial phototherapy and dentin remineralization promotion. This water-responsive fluid-hydrogel conversion system adapts to the irregular root surface in the dynamic wet environment, holding promise for addressing root caries. STATEMENT OF SIGNIFICANCE: Root caries bring a heavy burden to the aging society, but the irregular root surface and dynamic moist oral environment always hinder non-surgical therapeutic effects. Here, we propose a water-responsive fluid-hydrogel conversion strategy aimed at mechanical self-regulation on the irregular and wet root interface to construct a functional structural platform. The liquid system (ST-BP-U) that prebreak intermolecular hydrogen bonds can easily spread on irregular surfaces and dentin tubules. When encountering water, hydrogen bonds re-form, and BP increases the crosslinking of the hydrogel formed in situ. Based on this firm wet-adhesion platform, it provides powerful phototherapy effects and promotes dentin remineralization. This fluid-hydrogel conversion system turns the disadvantages of wet environment into advantages, offering a promising strategy for root caries.

Veillonella parvula promotes root caries development through interactions with Streptococcus mutans and Candida albicans.

Root caries is a subtype of dental caries that predominantly impacts older adults. The occurrence and progression of root caries are associated with the homeostasis of dental plaque biofilm, and microbial synergistic and antagonistic interactions in the biofilm play a significant role in maintaining the oral microecological balance. The objective of the current study was to investigate the role of Veillonella parvula in the microbial interactions and the pathogenesis of root caries. The analysis of clinical samples from patients with/without root caries revealed that Veillonella and V. parvula were abundant in the saliva of patients with root caries. More importantly, a significantly increased colonization of V. parvula was observed in root carious lesions. Further in vitro biofilm and animal study showed that V. parvula colonization increased the abundance and virulence of Streptococcus mutans and Candida albicans, leading to the formation of a polymicrobial biofilm with enhanced anti-stress capacity and cariogenicity, consequently exacerbating the severity of carious lesions. Our results indicate the critical role of V. parvula infection in the occurrence of root caries, providing a new insight for the etiological investigation and prevention of root caries.

Low Salivary IgA Levels Against PAc (361-386) as a Risk Factor for Root Caries in Older Adults.

OBJECTIVES: This study aimed to assess the intricate relationship between salivary IgA antibody levels to PAc (361-386) (PPA), mutans streptococci colonization, and root caries development in older adults. MATERIALS AND METHODS: This study included 307 participants aged 76 years residing in Niigata city, Japan. Clinical oral examinations were performed at baseline in 2004 and 1 year later, during which the total number of untreated and treated root caries was assessed using the root decayed, filled tooth (DFT) index. The stimulated saliva samples were collected using the spitting method during the baseline survey. Salivary IgA antibody levels to amino acid residues 361-386 of Streptococcus mutans PAc were quantified using an enzyme-linked immunosorbent assay. Statistical analyses, including the χ2 test, Mann-Whitney U test, and logistic regressions, were performed to examine the association of increased root DFT with the independent variables. RESULTS: Among the 307 participants (53.1% men), the mean root DFT at baseline was 3.77 ± 3.66, and 36.5% of the study sample exhibited increased root DFT after 1 year with a mean increment of 0.36 ± 0.48. Participants with increase in root DFT after 1 year had significantly higher rates of low PPA levels (≤ 25th percentile) than those without increased root DFT (p = 0.020). Low PPA levels (≤ 25th percentile) were significantly more likely to have an increased risk of root caries development compared with PPA levels > 25th percentile (adjusted OR: 1.88, 95% CI: 1.09-3.25). CONCLUSION: Low PPA levels and root caries incidence correlated significantly, suggesting that low levels of salivary IgA antibody to PAc (361-386) may serve as a risk factor for increased root caries in older adults.

Engineering a dysbiotic biofilm model for testing root caries interventions through microbial modulation.

BACKGROUND: This study aimed to engineer and optimise a dysbiotic biofilm model to develop in vitro root caries for investigating microbial modulation strategies. The model involved growing complex biofilms from a saliva inoculum collected from four volunteers using two strategies. In the first strategy ("pre-treatment strategy"), bovine root slabs were used, and two natural compounds were incorporated at time 0 of the 10-day biofilm experiment, which included sucrose cycles mimicking the cariogenic environment. In the second strategy ("post-treatment strategy"), mature biofilms were grown in a modified Calgary biofilm device coated with collagen and hydroxyapatite for 7 days and then were exposed to the same natural compounds. The metatranscriptome of each biofilm was then determined and analysed. Collagenase activity was examined, and the biofilms and dentine were imaged using confocal and scanning electron microscopy (SEM). Mineral loss and lesion formation were confirmed through micro-computed tomography (µ-CT). RESULTS: The pH confirmed the cariogenic condition. In the metatranscriptome, we achieved a biofilm compositional complexity, showing a great diversity of the metabolically active microbiome in both pre- and post-treatment strategies, including reads mapped to microorganisms other than bacteria, such as archaea and viruses. Carbohydrate esterases had increased expression in the post-treated biofilms and in samples without sugar cycles, while glucosyltransferases were highly expressed in the presence of sucrose cycles. Enrichment for functions related to nitrogen compound metabolism and organic cyclic component metabolism in groups without sucrose compared to the sucrose-treated group. Pre-treatment of the roots with cranberry reduced microbial viability and gelatinase (but not collagenase) activity (p < 0.05). SEM images showed the complexity of biofilms was maintained, with a thick extracellular polysaccharides layer. CONCLUSIONS: This root caries model was optimized to produce complex cariogenic biofilms and root caries-like lesions, and could be used to test microbial modulation in vitro. Pre-treatments before biofilm development and cariogenic challenges were more effective than post-treatments. The clinical significance lies in the potential to apply the findings to develop varnish products for post-professional tooth prophylaxis, aiming at implementing a strategy for dysbiosis reversal in translational research. Video Abstract.

Cross-sectional survey and analysis of factors influencing the prevalence of dental caries among older individuals aged 65-74 in Guangdong Province in 2021.

BACKGROUND: The prevalence of oral diseases is subject to change over time. In 2021, Guangdong Province conducted its fourth survey assessing the oral health status of individuals aged 65-74. MATERIALS AND METHODS: Evaluation criteria and potential influencing factors were identified. A sample of residents aged 65-74 from 13 designated monitoring sites in Guangdong Province was randomly selected for the study. Spearman correlation analysis was employed to investigate the clinical correlation between influencing factors and evaluation criteria. Negative binomial and zero-inflated negative binomial regression models were utilized to examine the factors influencing caries prevalence. In contrast, logistic regression was employed to identify the risk factors for caries occurrence. A p-value of ≤0.05 was considered statistically significant. RESULTS: The prevalence of caries rate of crowns, roots, and teeth were 76.36%, 52.25%, and 79.2%, respectively. Individuals with periodontal pockets exhibited a significantly higher risk of root caries. The presence of dental calculus significantly exacerbated the occurrence of crown, root, and dental caries, and increased the risk of crown and dental caries. Consuming sweet foods once or more a week notably increased the average root decayed score (D of roots), the prevalence rate of root caries, and the D score of the Decayed, Missing, and Filled teeth [DMFT] index in individuals already afflicted with this condition. Similarly, the consumption of sweetened drinks significantly elevated the risk of crown and root caries, exacerbating overall caries progression. Frequencies of manual toothbrush and toothpick cleaning showed a negative correlation with average tooth missing score (MT). In contrast, the frequency of manual/electric toothbrush and toothpick cleaning was negatively correlated with the DMFT index. Engaging in dental diagnosis and treatment behaviors significantly increased the number of filled crowns (F), MT, and DMFT scores while reducing the prevalence of dental caries. CONCLUSIONS: In Guangdong Province, caries prevalence among older individuals aged 65-74 remains substantial. Relevant professionals and institutions must provide comprehensive guidance and assistance to the older population, emphasizing the importance of reducing the consumption of sweets and sweetened beverages, adopting correct tooth brushing techniques and frequency (at least twice daily), timely treatment of periodontal diseases, conducting regular epidemiological caries surveys, and addressing economic barriers to accessing caries diagnosis and treatment services.

A Cross-Sectional Study to Assess Diabetes as a Risk Factor for Root Caries Amongst the Elderly Population in Udupi District, Karnataka State, India.

Objectives: To compare the prevalence of root surface carious lesions among the nondiabetic and diabetic elderly population and its association with various risk factors. Methods: An observational analytical cross-sectional study was conducted among 800 elderly participants, 431 males and 369 females, aged 50 years and above, with a minimum of ten teeth present, with 400 being diabetic and 400 nondiabetic from the various hospitals of the Udupi district. Demographics, socioeconomic status, oral hygiene practices, oral abusive habits, and history of type 2 diabetes were collected using an interviewer-administered questionnaire followed by an intraoral examination to assess root caries. The primary outcome measure was the presence of any carious or filled root surface. Binary logistic regression univariate analysis was done for all the predictor variables, and those with significant associations were further analyzed by multivariate analysis with the enter method in a single-step model. An appropriate nomogram was designed for risk prediction. Results: Overall, the root caries prevalence was 37.3%, and the mean root caries index was 14.28%. The prevalence of root caries was 46% in people with diabetes and 28.5% in nondiabetics. Participants with type 2 diabetes, less education, low socioeconomic status, and using finger cleaning had a significantly higher risk of developing root caries. Additionally, those who used removable partial dentures (RPDs) were found to be 4.65 times more likely to have root caries than those who did not use RPDs. Conclusion: Elderly diabetics are at a higher risk for developing root caries and are strongly advised to maintain good oral hygiene practices and to undergo periodic dental evaluations. Therefore, it is crucial to emphasize early diagnosis and treatment of root caries in this population.

Comparative analysis of microbiome in coronal and root caries.

BACKGROUND: The global rise in the elderly population has increased the prevalence of root caries. Streptococcus mutans, Lactobacilli and Actinomyces are considered the primary pathogens of dental caries in culture-based studies. This study aimed to investigate bacterial profiles in coronal and root caries lesions and determine the association of specific bacterial genera at each site. METHODS: Dentine samples from carious lesions were collected from 22 extracted teeth using an excavator. Microbial DNA was extracted from the samples using a protocol developed for this study. 16S rRNA gene amplicon sequencing was employed for microbial analysis. PCR amplification targeted the V3-V4 region of the bacterial 16S rRNA, and the amplicon sequencing used an Illumina MiSeq system (2 × 300 bp paired-end reads). Statistical analysis was performed by the Phyloseq and DESeq2 packages in R. RESULTS: In coronal caries, Olsenella, Lactobacillus and Prevotella were the most prevalent genera, comprising approximately 70% of the microbiome community. In the root caries, however, although Olsenella, Prevotella and Lactobacillus remained the dominant genera, they accounted for only half of the microbiome community. This study identified significant differences in alpha diversity indices between the coronal and root caries. LEfSE analysis revealed several unique genera in each caries lesion. CONCLUSION: The microbiome of root caries lesions was richer and more complex than the coronal caries microbiota. The results suggest that lesion-related variations in the oral microflora may be detected in carious dentine.

Challenges in differential diagnosis and treatment of cervical root resorption vs. root caries.

External cervical root resorption may be occasionally mistaken for root caries and vice versa. Radiographical and clinical differential diagnoses of cervical root resorption and root caries are essential for correct treatment planning and a successful treatment outcome. This article reviews the contemporary literature and summarises the prevailing professional consensus pertaining to external cervical root resorption. Clinical diagnostics which help distinguish cervical root resorption from root caries are outlined and treatment approaches of external cervical root resorption are discussed.

Cross-Sectional Associations between Nutrient Intake and Tooth Decay in Older Australian Men: The Concord Health and Ageing in Men Project.

Poor nutrition is a risk factor for dental decay in younger people. However, except for sugar, it is unclear if this is true in older age groups. The aim of this study was to analyze the possible associations between overall dietary intake of nutrients and diet quality and the presence of dental decay in community-dwelling older men. A cross-sectional analysis of a longitudinal study with a standardized validated diet history assessment and comprehensive oral health examination in 520 community-dwelling men (mean age: 84 years) participating in the Concord Health and Ageing in Men Project. Nutrient reference values were used to determine if individual micronutrients and macronutrients were meeting recommendations. Acceptable macronutrient distribution ranges (AMDRs) were attained for fat and carbohydrate intakes and were incorporated into a dichotomous variable to determine if the participants were consuming a high fat-low carbohydrate diet. Diagnosis of coronal caries was based on visual criteria and inspection and was completed on each of the five coronal surfaces. Root surface caries was textual changes across four root surfaces. This diagnosis was used to categorize participants by the presence and severity of coronal and root caries. The adjusted logistic regression showed not meeting the recommended intakes for thiamin (odds ratio [OR]: 2.32 95% confidence interval [CI] 1.15-4.67), and zinc (OR: 3.33, 95% CI: 1.71-6.48) were associated with presence of severe root decay. Adjusted analysis also showed that participants who were outside the recommended AMDR for fat (OR: 0.61, 95% CI: 0.38-0.98) and those who consumed a high fat and low carbohydrate diet (OR: 0.56, 95% CI: 0.35-0.91) were less likely to have coronal tooth decay. Our study shows associations between micronutrients and macronutrients and coronal and root surface decay. Although this study cannot prescribe causality or be generalized to all older adults, diet has a possible association with dental decay in older men.

Enhancement of mineral density and mechanical properties in root caries treated with silver diammine fluoride and glass ionomer cement, with emphasis on silver ion distribution.

OBJECTIVES: This study aimed to measure the distribution of silver ion (Ag+), mineral recovery, and nanohardness in carious lesions and comprehensively evaluate the degree of dentin restoration. METHODS: Sixty human teeth with root caries were randomly assigned to the control, silver diammine fluoride (SDF) [Safo], and SDF+Glass ionomer cement (GIC) treatment [Safo+Fuji] groups. Micro-computed tomography (micro-CT) was performed at five time points for each sample before/after treatment to evaluate mineral density within and around carious lesions. Three months following treatment, 12 samples were selected for synchrotron radiation X-ray fluorescence analysis to evaluate Ag+ distribution, while 15 samples were selected for nanoindentation. Data were analyzed using Dunnett's T3 test for micro-CT and Wilcoxon rank sum test with Bonferroni correction (p = 0.017) for nanoindentation. The correlation between hardness and mineral change was analyzed using the Spearman rank correlation coefficient. RESULTS: The Safo and Safo+Fuji groups showed significantly higher mineral recovery rates than did the control group (p < 0.001). In the Safo group, Ag+ accumulated in the deeper layers rather than the superficial layer of caries. In the Safo+Fuji group, Ag+ was found evenly distributed throughout caries, with only a few Ag+ detected in the GIC layer. Hardness in the Safo+Fuji group was significantly higher compared with the Safo group at depths in the range of 10-50 µm. CONCLUSION: In the presence of GICs, SDF exhibited high remineralization capacity when diffusing throughout carious lesions over time. Combined treatment with SDF and GIC could strengthen root dentin even in the presence of caries. CLINICAL SIGNIFICANCE: We found that combination treatment with SDF and GIC could increase mineral density in caries and improve the hardness of the tooth structure compared with fluoride-based agents alone. These findings might pave the way for future clinical trials to determine the therapeutic potential of nanotechnology-based restorative materials.

Decision making and management of root caries: A practice-based survey.

OBJECTIVES: With increasing life expectancy and improved preventive measures, teeth are retained longer, leading to a rise in prevalence of root caries lesions (RCL). However, little is known about how dentists manage this condition. The present survey aimed to evaluate the knowledge of Swiss dentists on decision making and management of RCL. METHOD: The survey evaluated dentists' knowledge, clinical routines, and demographics concerning RCL. Dentists were contacted via email and local newsletters, and 383 dentists from 25 (out of 26) cantons responded. Mann-Whitney U test, χ2 test, intraclass correlation coefficients, Spearman correlation and Chi Square were used. RESULTS: The dentists had a mean(SD) working experience of 22.5(12) years. Most dentists correctly classified an inactive (67%) and an active (81%)RCL. Although the inactive lesion did not call for restorative treatments, 61% of the dentist declared they would restore it. From the active lesion,83% would restore it. The invasive treatments leaned toward complete caries excavation with composite resin as preferred restorative material. There were significant correlations between material choice and expected success rates. Among the non-invasive options, oral hygiene instructions and (highly-)fluoridated toothpaste were favored. Most dentists declared having a recall system for such patients, with biannual follow-ups preferred. The dentists' place of education significantly influenced restorative decisions (p < 0.001), while participants' age (≥60years) impacted activity status (p = 0.048) and restorative decisions (p = 0.02). CONCLUSION: Material preferences for non-invasive or invasive management varied greatly and there were minimal differences in the management of inactive or an active RCL. Moreover, diagnosing active lesions appeared easier than diagnosing inactive ones. CLINICAL SIGNIFICANCE: Despite diverse material preferences for (non-)invasive treatments, a strong positive correlation existed between the chosen restorative material and its expected 2-year success rate. Moreover, diagnosing active lesions appeared easier than diagnosing inactive ones. The outcome emphasis the need to align guideline recommendations with their application in private dental practices.

Immediate and sustained root caries prevention of fluoride varnish combined with toothpastes: findings of clinical relevance?

DESIGN: An in vitro study to determine the immediate and sustained effect of fluoride varnish and its combination with fluoride toothpastes in preventing the development of root caries. CASE SELECTION: Human root dentine samples (150) were randomly divided into five experimental protocols of 30 specimens each: 1) fluoride varnish (22,600 ppm fluoride and 1-5% CPP-ACP); 2) fluoride varnish followed by Paste One (1100 ppm sodium fluoride and CPP-ACP); 3) fluoride varnish followed by Paste Plus (900 ppm sodium fluoride and CPP-ACP); 4) fluoride varnish followed by Paste One and Paste Plus; and 5) no treatment (control). A layer of varnish was applied to specimens except the control group and was left in situ for 18 h. The varnish layer was removed, and the various toothpaste treatments were initiated. Half of the specimens in each group were assigned to a short-term incubation model in which they were immediately subjected to a 7-day cariogenic challenge consisting of a combination of human saliva and artificial saliva containing 2% sucrose. The other half of the specimens in each group were assigned to the long-term incubation model in which the experimental protocol was continued for 8 weeks before initiating the seven-day cariogenic challenge. The protocols were evaluated by assessing dentine porosity (rhodamine intensity), mineral density, biofilm biomass, and viability assays. DATA ANALYSIS: Confocal laser scanning microscopy was used to determine dentine porosity and Levene's test was used to verify the assumption of equality of variances and normal distribution of errors before two-way ANOVA and the Games-Howell test were carried out at a significance level of 0.05 for both incubation models. Microcomputed tomography was used to determine mineral density with statistical analysis involving Levene's test, two-way ANOVA and Tukey's test at a significance level of 0.05 for both incubation models. Biomass was evaluated using a biofilm biomass assay with analysis of optical density data using Levene's test, ANOVA and Scheffe's test at a significance level of 0.05. RESULTS: For both the short- and long-term incubation models, all the experimental regimes resulted in a statistically significant decrease in dentine porosity and an increase in mineral density when compared to the control group. Fluoride varnish followed by both pastes and fluoride varnish followed by Paste One resulted in a statistically significant decrease in dentine porosity for some depths in both models when compared to fluoride varnish alone. Changes in dentine porosity and mineral density were observed within groups over time. All the experimental regimes demonstrated anti-biofilm effects. Immediate and sustained anti-caries effects were observed for all preventive protocols, with the combination of fluoride varnish and Paste One resulting in superior additional anti-caries effects. CONCLUSIONS: The authors concluded that all protocols demonstrated immediate and sustained anti-caries effects against the development of root caries despite variations in effects over time. The combination of fluoride varnish and Paste One resulted in additional anti-caries effects that were consistently superior, with no additional effects being observed when Paste Plus was added in combination. The authors suggest that, within the study's limitations, topical fluoride varnish seems to have a protective effect on root surfaces for up to eight weeks and that fluoride varnish should be considered as an important adjunct strategy in the prevention of root caries in older adults.

The action of microbial collagenases in dentinal matrix degradation in root caries and potential strategies for its management: a comprehensive state-of-the-art review.

Conventional views associate microbial biofilm with demineralization in root caries (RC) onset, while research on their collagenases role in the breakdown of collagen matrix has been sporadically developed, primarily in vitro. Recent discoveries, however, reveal proteolytic bacteria enrichment, specially Porphyromonas and other periodontitis-associated bacteria in subgingivally extended lesions, suggesting a potential role in RC by the catabolism of dentin organic matrix. Moreover, genes encoding proteases and bacterial collagenases, including the U32 family collagenases, were found to be overexpressed in both coronal and root dentinal caries. Despite these advancements, to prove microbial collagenolytic proteases' definitive role in RC remains a significant challenge. A more thorough investigation is warranted to explore the potential of anti-collagenolytic agents in modulating biofilm metabolic processes or inhibiting/reducing the size of RC lesions. Prospective treatments targeting collagenases and promoting biomodification through collagen fibril cross-linking show promise for RC prevention and management. However, these studies are currently in the in vitro phase, necessitating additional research to translate findings into clinical applications. This is a comprehensive state-of-the-art review aimed to explore contributing factors to the formation of RC lesions, particularly focusing on collagen degradation in root tissues by microbial collagenases.

Organization for Caries Research-European Federation of Conservative Dentistry Consensus Report on Clinical Recommendations for Caries Diagnosis Paper II: Caries Lesion Activity and Progression Assessment.

INTRODUCTION: This consensus paper provides recommendations for oral health professionals on why and how to assess caries activity and progression with special respect to the site of a lesion. METHODS: An expert panel was nominated by the executive councils of the European Organization for Caries Research (ORCA) and the European Federation of Conservative Dentistry (EFCD). The steering committee built three working groups that were asked to provide recommendations on (1) caries detection and diagnostic methods, (2) caries activity and progression assessment, and (3) obtain individualized caries diagnoses. The experts of work group 2 phrased and agreed on provisional general and specific recommendations on caries lesion activity and progression, based on a review of the current literature. These recommendations were then discussed and refined in a consensus workshop followed by an anonymous Delphi survey to determine the agreement on each recommendation. RESULTS: The expert panel agreed on general (n = 7) and specific recommendations (n = 6). The specific recommendations cover coronal caries on pits and fissures, smooth surfaces, proximal surfaces, as well as root caries and secondary caries/caries adjacent to restorations and sealants. 3/13 recommendations yielded perfect agreement. CONCLUSION: The most suitable method for lesion activity assessment is the visual-tactile method. No single clinical characteristic is indicative of lesion activity; instead, lesion activity assessment is based on assessing and weighing several clinical signs. The recall intervals for visual and radiographic examination need to be adjusted to the presence of active caries lesions and recent caries progression rates. Modifications should be based on individual patient characteristics.

Evaluation of toothpastes for treating root carious lesions - a laboratory-based pilot study.

BACKGROUND: Root caries is preventable and can be arrested at any stage of disease development. The aim of this study was to investigate the potential mineral exchange and fluorapatite formation within artificial root carious lesions (ARCLs) using different toothpastes containing 5,000 ppm F, 1,450 ppm F or bioactive glass (BG) with 540 ppm F. MATERIALS AND METHODS: The crowns of each extracted sound tooth were removed. The remaining roots were divided into four parts (n = 12). Each sample was randomly allocated into one of four groups: Group 1 (Deionised water); Group 2 (BG with 540 ppm F); Group 3 (1,450 ppm F) and Group 4 (5,000 ppm F). ARCLs were developed using demineralisation solution (pH 4.8). The samples were then pH-cycled in 13 days using demineralisation solution (6 h) and remineralisation solution (pH 7) (16 h). Standard tooth brushing was carried out twice a day with the assigned toothpaste. X-ray Microtomography (XMT) was performed for each sample at baseline, following ARCL formation and after 13-day pH-cycling. Scanning Electron Microscope (SEM) and 19F Magic angle spinning nuclear magnetic resonance (19F-MAS-NMR) were also performed. RESULTS: XMT results showed that the highest mineral content increase (mean ± SD) was Group 4 (0.09 ± 0.05), whilst the mineral content decreased in Group 1 (-0.08 ± 0.06) after 13-day pH-cycling, however there was evidence of mineral loss within the subsurface for Groups 1, 3 and 4 (p < 0.05). SEM scans showed that mineral contents within the surface of dentine tubules were high in comparison to the subsurface in all toothpaste groups. There was evidence of dentine tubules being either partially or completely occluded in toothpaste groups. 19F-MAS-NMR showed peaks between - 103 and - 104ppm corresponding to fluorapatite formation in Groups 3 and 4. CONCLUSION: Within the limitation of this laboratory-based study, all toothpastes were potentially effective to increase the mineral density of artificial root caries on the surface, however there was evidence of mineral loss within the subsurface for Groups 1, 3 and 4.

A cost-effectiveness analysis of fluoride varnish application in preventing Root caries in elderly persons: a Markov simulation study.

BACKGROUND: Root caries are prevalent issues that affect dental health, particularly among elderly individuals with exposed root surfaces. Fluoride therapy has shown effectiveness in preventing root caries, but limited studies have addressed its cost-effectiveness in elderly persons population. This study aimed to evaluate the cost-effectiveness of a fluoride treatment program for preventing root caries in elderly persons within the context of Chinese public healthcare. METHODS: A Markov simulation model was adopted for the cost-effectiveness analysis in a hypothetical scenario from a healthcare system perspective. A 60-year-old subject with 23 teeth was simulated for 20 years. A 5% sodium fluoride varnish treatment was compared with no preventive intervention in terms of effectiveness and cost. Tooth years free of root caries were set as the effect. Transition probabilities were estimated from the data of a community-based cohort and published studies, and costs were based on documents published by the government. The incremental cost-effectiveness ratio (ICER) was calculated to evaluate cost-effectiveness. Univariate and probabilistic sensitivity analyses were performed to evaluate the influence of data uncertainty. RESULTS: Fluoride treatment was more effective (with a difference of 10.20 root caries-free tooth years) but also more costly (with a difference of ¥1636.22). The ICER was ¥160.35 per root caries-free tooth year gained. One-way sensitivity analysis showed that the risk ratio of root caries in the fluoride treatment group influenced the result most. In the probabilistic sensitivity analysis, fluoride treatment was cost-effective in 70.5% of the simulated cases. CONCLUSIONS: Regular 5% sodium fluoride varnish application was cost-effective for preventing root caries in the elderly persons in most scenarios with the consideration of data uncertainty, but to a limited extent. Improved public dental health awareness may reduce the incremental cost and make the intervention more cost-effective. Overall, the study shed light on the economic viability and impact of such preventive interventions, providing a scientific basis for dental care policies and healthcare resource allocation.

Diagnosing and recording root caries: A survey among Swiss dentists.

OBJECTIVES: Despite the increase in the root caries prevalence, little is still known about how dentists manage this condition. The present study aimed to evaluate the knowledge of dentists on diagnosing and recording root caries lesions (RCL). METHODS: The survey consisted of three domains: (1) dentists' knowledge on diagnosing, recording and managing RCL; (2) information about their current general clinical routines; and (3) their demographics. The four Swiss Universities distributed the survey via e-mail lists for alumni or professionals participating in continuing education. The data was quality checked. Construct validity, internal reliability and intraclass correlation (ICC) were assessed. RESULTS: The survey was answered by 383 dentists from 25(out of 26) cantons [mean(SD) working experience: 22.5(12) years]. The majority replied that they see less than 5 patients with RCL per week, whereas 41 have at least 5 per week, and 40 % (157 dentists) do not distinguish RCL from coronal caries in their patients' medical records. When diagnosing active RCL, tactile sensation was the most predominant criterion (n = 380), whereas color (n = 224) and visual appearance (n = 129) of the lesion were less often selected. The most often chosen risk factors for RCL were poor oral hygiene and presence of biofilm.The responses were significantly influenced by the participants' place of education, their age and working area. CONCLUSION: The present survey highlights the huge diversity in diagnosing, recording and assessing risk factors of RCL. The benefits of an appropriate diagnosis, recording and management of risk factors of RCL should be highlighted in under- and postgraduate dental education. CLINICAL SIGNIFICANCE: A great diversity in diagnosing, recording and assessing risk factors of RCL was observed, which migh strongly impact how dentists manage RCL. The study emphasizes the necessity for intensive efforts to bridge the gap between guideline recommendations and their implementation in private dental practices.

Clinical Investigation of the Inhibitory Effects of Tooth-Coating Materials on Initial Active Root Caries: A Pilot Randomized Controlled Trial.

Background and Objectives: Caredyne ZIF-C is a novel, capsule-mixed zinc-containing prototype glass ionomer cement (GIC). Zinc ions are reported to inhibit root dentin demineralization, dentin collagen degradation, bacterial growth, acid production, and in vitro bacterial biofilm formation. However, the effectiveness of GICs against initial root caries lesions is unclear. Therefore, this study aimed to evaluate the efficacy of GICs, especially the new zinc-containing Caredyne ZIF-C GIC, as tooth-coating materials in patients with initial active root caries. Materials and Methods: A total of 58 lesions in 47 older adults (age > 65 years) were randomly allocated to one of the following three groups: Caredyne ZIF-C, Fuji VII (a conventional GIC), and sodium fluoride (NaF). All the lesions were treated with the assigned materials without removing the infected dentin, and the rates of dental plaque attachment and coating material fall-out were evaluated after 3, 6, and 12 months. The failure rate was defined as the number of teeth that needed restoration due to caries progression. Results: The plaque attachment rates tended to be lower in the material-coated root surfaces than in the healthy exposed root surfaces after 3, 6, and 12 months, although the differences among the three groups were not significant. Moreover, the coating material fall-out rate tended to be lower in the Caredyne ZIF-C group than in the Fuji VII group. There was no significant difference in the failure rate among the three groups at the 12 months mark. Conclusions: Though this pilot study offers a new direction for suppressing the progression of initial active root caries by controlling plaque attachment using GICs including Caredyne ZIF-C, clinical studies with a larger sample size are needed.

The effect of silver nanoparticles in addition to sodium fluoride on remineralization of artificial root dentin caries.

BACKGROUND: Silver nanoparticle was developed to overcome the drawback of silver diamine fluoride. However, evidence is limited, especially in root caries. The aim of this study was to evaluate the remineralization effect of silver nanoparticles on root caries. MATERIALS AND METHODS: Fifty-five root human dentin slices size 5 × 5 mm2 from patients aged over 60 years old were immersed in demineralized solution to create artificial caries. Specimens were allocated into five groups according to the remineralizing agents: silver diamine fluoride (SDF), silver nanoparticles solution (AgNPs), silver nanoparticle solution followed by sodium fluoride varnish (AgNPs+NaF), sodium fluoride varnish (NaF), and tap water. After 8 days of pH-cycling challenge, the microhardness test, lesion depth evaluation, dentin surface morphology, and elemental analysis were performed. Data was analysed using F-test One-way ANOVA followed by Tukey's post hoc test and paired T-test. RESULTS: All test groups demonstrated a significantly higher microhardness value and lower lesion depth compared with the control group. AgNPs+NaF and NaF-treated groups showed lower efficacy than SDF. Crystal precipitation was presented in all groups composed of silver. CONCLUSION: Addition of fluoride varnish did not benefit for silver nanoparticles in preventing further demineralization. SDF provides the highest effectiveness in elderly root carious dentin.

Systematic review and network meta-analysis of restorative therapy and adhesive strategies in root caries lesions.

AIM: This systematic review and network meta-analysis (NMA) aimed to establish a clinically relevant hierarchy of the different adhesive and/or restorative approaches to restore cavitated root caries lesions through the synthesis of available evidence. MATERIALS AND METHODS: A systematic search was conducted in Medline/Web of Science/Embase/ Cochrane Library/Scopus/grey literature. RCTs investigating ≥2 restorative strategies (restorative /adhesive materials) for root caries lesions in adult patients were included. Risk of bias within studies was assessed (Cochrane_RoB-2) and the primary outcome was survival rate of restorations at different follow-up times (6-/12-/24-months). Network meta-analyses were conducted using a random effects model stratified by follow-up times. I2-statistics assessed the ratio of true to total variance in the observed effects. All available combinations of adhesives (1-SE: one-step self-etch; 2-3ER: two-/three-step etch-and-rinse) and restorative materials (conventional composite (CC) as well as conventional and resin-modified glass ionomer cements (GIC, RMGIC)) were included. Risk of bias across studies and confidence in NMA (CINeMA) were assessed. RESULTS: 547 studies were identified and nine were eligible for the NMA. In total, 1263 root caries lesions have been restored in 473 patients in the included clinical trials. Patients involved were either healthy (n = 6 trials), living in nursing homes (n = 1 trial) or received head-and-neck radiotherapy (n = 2 trials). There was statistically weak evidence to favour either of material/material combination regarding the survival rate. A tendency for higher survival rate (24-months) was observed for 2-3ER/CC (OR24mths 2.65; 95%CI=1.45/4.84) as well as RMGIC (OR24mths 2.05; 95%CI=1.17/3.61) compared to GIC. These findings were though not statistically significant and confidence of the NMA was low. CONCLUSION: An evidence-based choice of restorative strategy for managing cavitated root caries lesions is currently impossible. There is a clear need for more standardised, well-designed RCTs evaluating the retention rate of root caries restoration approaches.