Association of Root Biofilm Bacteriome with Root Caries Lesion Severity and Activity.

INTRODUCTION: This research aimed to assess the association of root biofilm bacteriome with root caries lesion severity and activity in institutionalised Colombian elderlies and was conducted to gather data on the root caries bacteriome in this population. METHODS: A bacteriome evaluation of biofilm samples from sound and carious root surfaces was performed. Root caries was categorised (ICDAS Root criteria) based on severity (sound surfaces, initial: non-cavitated, moderate/extensive combined: cavitated) and activity status (active and inactive). DNA was extracted and the V4 region of the 16S rRNA gene was sequenced; afterwards the classification of features was conducted employing amplicon sequence variants and taxonomic assignment via the Human Oral Microbiome Database (HOMD). Bacterial richness, diversity (Simpson's and Shannon's indices), and relative abundance estimation were assessed and compared based on root caries severity and activity status (including Sound surfaces). RESULTS: A total of 130 biofilm samples were examined: sound (n = 45) and with root caries lesions (n = 85; by severity: initial: n = 41; moderate/extensive: n = 44; by activity: active: n = 60; inactive: n = 25). Species richness was significantly lower in biofilms from moderate/extensive and active groups compared to sound sites. There was a higher relative abundance of species like Lechtotricia wadei, Capnocytophaga granulosa, Cardiobacterium valvarum, Porphyromonas pasteri - in sound sites; Dialister invisus, Streptococcus mutans, Pseudoramibacter alactolyticus and Bacteroidetes (G-5) bacterium 511 - in moderate/extensive lesions, and Fusobacterium nucleatum subsp. animalis, Prevotella denticola, Lactobacillus fermentum, Saccharibacteria (TM7) (G-5)bacterium HMT 356 - in active lesions. CONCLUSION: Root caries bacteriome exhibited differences in species proportions between the compared groups. Specifically, cavitated caries lesions and active caries lesions showed higher relative abundance of acidogenic bacteria.

Effect of Three Chemical Agents on Stain Removal from Dentin Caries Lesions Treated with Silver Diamine Fluoride.

INTRODUCTION: This in vitro study aimed to evaluate the effect of three different chemical agents on stain removal and mineral uptake of artificial dentin caries (ADC) lesions treated with silver diamine fluoride (SDF). METHODS: Baseline L*a*b* values were determined in polished human permanent dentin blocks, and ADC lesions were induced with an acid gel for 1 week. Samples were assigned to four groups; in three groups, half of each sample received SDF (30% SDF for 3 min), while the other half received SDF followed by a bleaching treatment protocol (garlic extract, bentonite, or 35% hydrogen peroxide). The fourth group had one SDF-treated half and one half without SDF. Color changes (ΔE) were measured by spectrometry, and transversal microradiography was used to quantify integrated mineral loss (ΔZ) 24 h after treatment (SDF or SDF + bleaching). A two-way mixed ANOVA was applied to thirty percent. RESULTS: SDF application increased mineral uptake by ADC (p = 0.001). The type of chemical agent evaluated (p < 0.0001), time (p = 0.01), and their interaction (p < 0.0001) bleached the ADC treated with SDF. However, 35% hydrogen peroxide was the only compound with a bleaching effect (p < 0.001), without returning to baseline color. None of the compounds altered the mineral uptake effect of SDF (p = 0.30). CONCLUSION: This in vitro study showed mineral uptake effect in ACD within 24 h after SDF application and the ability of hydrogen peroxide to partially remove (reduction of 24%) the staining caused by SDF without affecting its mineral uptake effect.

Long-term clinical comparison of a resin-based composite and resin modified glass ionomer in the treatment of cervical caries lesions.

This 72-month study compared the clinical effectiveness of a resin-based composite (RBC) (Spectrum TPH3, Dentsply Sirona) with a resin-modified glass ionomer cement (RMGIC) (Riva Light Cure, SDI) in restoring cervical caries lesions (CCLs). Thirty-three patients, each with at least two CCLs, were enrolled. After caries removal, the dimensions of the cavities were recorded. In a split-mouth study design, a total of 110 restorations were randomly placed. Fifty-five restorations were placed with RBC using an etch-and-rinse adhesive system (Prime&Bond NT, Dentsply Sirona), while the remaining 55 were restored with RMGIC. The restorations were assessed at baseline, 6, 12, 18, 24, 36, 60, and 72 months according to modified USPHS criteria. Statistical analysis included Pearson Chi-square, Friedman tests, Kaplan Meier, and Logistic Regression analysis (p < 0.05). After 72 months, 47 restorations in 19 patients were evaluated (55% follow-up rate). Seventy-five percent of the RBC (n = 26) and 74% (n = 21) of the RMGIC restorations were fully retained. There were no significant differences between materials regarding retention and marginal adaptation (p > 0.05). Cavity dimensions, caries activity, and retention exhibited no correlation (p > 0.05). The increase in marginal staining in both groups over time was significant (p < 0.001). RMGIC restorations exhibited higher discoloration than RBC restorations (p = 0.014). At 72 months, three secondary caries lesions were detected in both restoration groups: two RMGIC and one RBC. There were no reports of sensitivity. After 72 months, both RBC and RMGIC restorations were clinically successful, with similar retention and marginal adaptation scores. However, it is noteworthy that RMGIC restorations tend to discoloration over time compared to RBC. The trial is registered in the database of "Clinical Trials". The registration number is NCT0372-2758, October 29, 2018.

Root caries in older adults: A co-citation network analysis (1980-2023).

BACKGROUND: Root caries affect the oral health and quality of life of older adults. This study examines the breadth of global research on this topic, aiming to clarify its expansive scope and to shed light on pertinent trends for new researchers in the field. OBJECTIVE: To identify key advances in root caries research as highlighted in high-quality articles from the Social Science Citation Index (SSCI) as well as to explore emerging trends and perspectives. MATERIALS AND METHODS: Using the Web of Science (WoS) database, we conducted a comprehensive review of articles related to root caries in older adults. Our focus was on finding high-quality SSCI articles, identifying major contributors, journals and research trends and exploring areas such as dentistry, oral surgery and medicine for potential future research. RESULTS: Our analysis included 192 articles, each of which was subjected to bibliometric and VOS viewer evaluations. The results revealed a concentration of studies in dentistry, oral surgery and medicine, with gaps identified in areas like anthropology, biochemistry, molecular biology and chemistry. A notable deficiency was found in root caries management. CONCLUSION: We discuss research gaps and propose future directions based on our findings, emphasising interdisciplinary research approaches.

Clinical parameters that affect performance and patient satisfaction of root-retained overdentures: A systematic review of randomised controlled clinical trials.

OBJECTIVE: To evaluate clinical parameters that affect the performance of root-supported overdentures (ROD) and to identify the possible factors that may affect it. BACKGROUND: ROD still serve as an alternative and successful treatment plan nowadays for partially edentulous patients. Nonetheless, there is not yet conclusive evidence about their clinical evaluation. MATERIALS AND METHODS: A search strategy was developed following a PIO (Population, Intervention, Outcome) framework including an electronic search in the following databases: PubMed, Cochrane Library and Scopus. The systematic search included only randomised controlled clinical trials (RCTs), published until January 2023 in English language and was performed by two independent reviewers. Quality assessment of the included studies was conducted according to the Cochrane Risk of Bias tool. RESULTS: The final selection of studies included 11 RCTs. Clinically relevant variables derived from this search were: Complications, with caries being the most frequently reported, periodontal aspects and bone changes around abutment teeth. Additionally, methods and clinical suggestions for the maintenance of these restorations and patient-related outcomes were assessed. According to the risk of bias assessment, nine studies were considered of high risk, whereas only 2 of low risk. A meta-analysis was not feasible. CONCLUSION: Within the limitations of this systematic review, ROD remain a viable treatment plan, offering better denture stability and bone preservation around abutment teeth and high patient satisfaction. Thorough oral hygiene and regular follow-ups are of utmost importance. Further well-designed RCTs are necessary for firmer conclusions.

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.

Depression and dental caries in US adults, NHANES 2015-2018.

PURPOSE: This study aimed to investigate the link between depression and untreated dental caries among adults in the United States. METHODS: Data were collected from the National Health and Nutrition Survey (2015-2018); respondents aged 20 years or older who completed a patient health questionnaire and underwent a comprehensive oral examination were included. Participants were categorized into three groups according to depressive symptoms as follows: those with no, mild, or moderate to severe depression. Data were weighted, and multiple potential covariates were included in the analysis to provide national estimates and account for the complex sample design. A multivariable weighted logistic regression model was performed to test the hypothesis that varying degrees of depression in American adults are associated with untreated dental caries. Subgroup analyses were performed based on age and gender after adjusting for potential covariates. A P value of <.05 was considered significant. RESULTS: Among 8740 participants, the prevalence of untreated coronal and root caries was 20.50% and 12.92%, respectively. Moderate to severe depression was a significant risk factor (odds ratio, 1.25; 95% confidence interval, 1.09-1.66) for untreated root caries. The risk of untreated root caries increased by 87% in young adults (aged 20-44 years) and by 46% in women with moderate to severe depression. The suest analysis revealed that the impact of moderate to severe depressive disorder on untreated root caries was non-significantly different between the age subgroup (p=0.09) and sex subgroup (p=0.51). However, depression was non-significantly associated with untreated coronal caries (mild depression: OR, 1.07; 95% CI, 0.85-1.34; moderate to severe depression 1.06; 95% CI, 0.83-1.36; respectively). CONCLUSION: The results of this study suggested a significant association between moderate and severe depression and untreated root caries; however, the association with untreated coronal caries was non-significant. In the United States, moderate and severe depression in adults is associated with root caries.

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.

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.

Immediate and Sustained Root Caries Prevention of Fluoride Varnish Combined with Toothpastes.

The aim of this study was to determine the immediate and sustained effect of a fluoride varnish and its combinations with toothpastes in preventing root caries development using a salivary microcosm in vitro model. Human root dentin specimens (n = 150) were randomly divided into 5 experimental protocols (n = 30): (1) Fluoride Varnish (V); (2) V followed by Paste One (V + PO); (3) V followed by Paste Plus (V + PP); (4) V followed by PO and PP (V + PO + PP); and (5) No treatment (control). One varnish layer was applied on the specimens (except for the control group) and kept for 18 h. Then, the varnish was removed and toothpaste treatments were initiated according to experimental groups. For the short-term incubation model (n = 15), the specimens were also immediately subjected to 7-day cariogenic challenge. For that, human saliva was used as bacterial inoculum and McBain artificial saliva containing 2% sucrose as growth medium. The other half of the specimens (n = 15) were used to study the varnish's sustained effect by long-term incubation (8 weeks) before cariogenic challenge. The protocols' anti-caries properties were evaluated by dentin porosity (rhodamine intensity; RI) and mineral density, while their anti-biofilm effects were evaluated using biofilm's biomass and viability assays. For short- and long-term incubation models, all experimental regimens resulted in statistically significant decreases (p < 0.05) in the RI (up to 180 µm and 120 µm, respectively) as well as higher mineral density compared to No treatment (p < 0.001). V + PO + PP and/or V + PO resulted in statistically lower RI compared to V for some depths (p < 0.05) in both models. There were changes in RI and mineral density within groups over time. All experimental treatments exhibited anti-biofilm effects. All prevention protocols exhibited immediate and sustained anti-caries effect against root caries development. The combination of a fluoride varnish with PO resulted in superior additional anti-caries effects.

A Bibliometric Analysis of Studies on Root Caries.

This study aimed to review the current state of the root caries field, explore the current hot topic, and anticipate future research frontiers. The Web of Science Core Collections was searched to acquire publications that were relevant to root caries from 1992 to 2021. After retrieval and manual screening, the co-occurrence and co-operation analysis of keywords and countries/institutions/authors were performed through CiteSpace and VOSviewer based on two periods (1992-2006 and 2007-2021). From 1992 to 2021, 451 unique publications were selected. The USA, which has been the center of international cooperation, has produced the most publications in the research area in 1992-2021. Journal of Dental Research and Caries Research are the main counterpart journals in the field of root caries. The University of London is the institution with the highest number of publications in the analyzed 30 years. "Demineralization," "remineralization," "aged," "dentin," and "fluoride" have been commonly used as keywords throughout the past 30 years. More studies from different aspects have been published in the field of root caries in recent years (2007-2021). The findings of this study provide a full picture of the last 30 years in this research area; hopefully, they also provide essential information for researchers and policymakers to make decisions.

Design, development and validation of a questionnaire to assess dentists' knowledge and experience in diagnosing, recording, and managing root caries.

OBJECTIVES: The prevalence of root caries is increasing globally, especially in the elderly population, and even though the number of patients with root caries lesions is augmenting, there are still many discrepancies in how dentists manage this condition. The present study aimed to develop and validate a questionnaire to evaluate how dentists diagnose, record and manage root caries lesions, and to verify the validity and reliability of this questionnaire. MATERIALS AND METHODS: An expert panel developed a self-administered questionnaire survey with three domains: (1) dentists' knowledge on diagnosis, recording, and managing root caries; (2) information about their current general clinical routines; (3) their demographics. The original English [E] version was translated into three different languages (French [F], German [G], Italian [I]), and subsequently back-translated into English by independent dentists. For the validation, 82 dentists (20-22 for each of the translated versions) accepted to answer the questionnaire at two different time-points (with 1-week interval). The data was quality checked. Construct validity, internal reliability, and intra-class correlation (ICC) were assessed. RESULTS: Seventy-seven dentists completed the questionnaire twice [E: 17; F: 19; G: 19; I: 22]. The mean ICC (standard deviation) was 0.98(0.03) for E, 0.90(0.12) for F, 0.98 (0.04) for G, and 0.98 (0.01) for I. Overall, the test-retest reliability was excellent (mean ICC (SD): 0.96 (0.08)). Furthermore, the questionnaire demonstrated good internal reliability (inter-observer reliability; Fleiss kappa: overall:0.27(fair); E:0.30 (fair); F: 0.33(fair); G: 0.33(fair); I: 0.89 (almost perfect)). CONCLUSION: The questionnaire was validated and is suitable to be used in the four languages to assess the knowledge of dentists on diagnosing, recording and managing root caries. CLINICAL SIGNIFICANCE: The present questionnaire was validated and seems to be a good tool to evaluate how dentists diagnose, record, and manage root caries lesions both in its original (English) and its translated (French, German, and Italian) versions.

Accuracy of different approaches for detecting proximal root caries lesions in vitro.

OBJECTIVES: The objective was to evaluate the diagnostic accuracy of radiographic evaluation (XR), visual-tactile assessment (VT), laser-fluorescence (LF) (DIAGNOdent Pen/KaVo), and near-infrared-light transillumination (NILT) (DIAGNOcam/KaVo) on proximal root caries lesions in vitro. METHODS: Two-hundred extracted permanent premolars and molars with and without proximal root caries lesions were allocated to 50 diagnostic models simulating the proximal contacts between teeth and mounted in a phantom dummy head. Two independent examiners used the diagnostic approaches to detect any or advanced root caries lesions, with histologic evaluation of the lesions serving as reference. Receiver operating characteristic (ROC) curves were employed, and sensitivity, specificity, and the area under the ROC curve (AUC) are calculated. Significant differences in mean AUCs between approaches were assumed if p < 0.05 (two-sample t-test). RESULTS: NILT was not applicable for proximal root caries detection. The sensitivity/specificity to detect any lesions was 0.81/0.63 for XR, 0.76/0.88 for VT and 0.81/0.95 for LF, and the sensitivity/specificity to detect advanced lesions was 0.43/0.94 for XR, 0.66/0.99 for VT, and 0.83/0.78 for LF, respectively. For both, any and advanced root caries lesions, mean AUCs for LF and VT were significantly higher compared to XR (p < 0.05). For any root caries lesions, LF was significantly more accurate than VT (p = 0.01), but not for advanced root caries lesions (p = 0.59). CONCLUSIONS: Under the in vitro conditions chosen, LF and VT were more accurate than XR to detect proximal root caries lesions, with LF being particularly useful for initial lesion stages. CLINICAL RELEVANCE: LF might be a useful diagnostic aid for proximal root caries diagnosis. Clinical studies are necessary to corroborate the findings.

Classification of a patient's caries activity based on lesion activity assessment among adults: findings from a prospective cohort study.

OBJECTIVE: To investigate whether the classification of a patient's caries activity based on lesion activity assessment can predict the increment and progression of coronal and root caries lesions among adults. METHODS: This population-based prospective cohort study followed 413 individuals (mean age 54.1) from southern Brazil for 4 years. Data collection included a questionnaire and clinical examination to record coronal/root caries and gingival recession. The main outcomes were caries increment measured as decayed, missing and filled tooth surfaces (DMFS) and caries progression (surface-level analysis). The main predictor variable was patients' caries activity at baseline ("caries-inactive" or "caries-active"). Negative binomial regression models (unadjusted and adjusted) were used. RESULTS: Caries-active individuals were more likely to present DMFS increment than caries-inactive ones when migrations among DMFS components were considered (IRR [incidence risk ratio] = 1.26, 95%CI [confidence interval] = 1.01-1.58). On the other hand, no such association was found when these migrations were disregarded. The risk for coronal caries progression on filled surfaces was 90% higher among caries-active patients (IRR=1.9; 95%CI=1.4-2.6). In addition, patient's caries activity was able to predict higher risk for root caries progression in newly exposed root surfaces (IRR=1.9; 95%CI=1.0-3.6). CONCLUSION: The classification of a patient's caries activity based on lesion activity was able to foresee lesion progression on the coronal and root surfaces more susceptible to caries among adults. Clinical relevance Classifying a patient's caries activity is a useful tool for the clinical management of dental caries in adults.

Effect of a single application of silver diamine fluoride on root caries after 12 months in institutionalised older adults-A randomised clinical trial.

OBJECTIVE: Silver diamine fluoride (SDF) has been shown to be highly effective against caries, in particular for arresting root surface caries and for dentine caries in primary teeth. SDF may complement fluoride varnish routines for treatment of root caries in nursing home residents. The aim of this randomised, single-blinded, placebo-controlled trial was to evaluate the additive effect of a single annual application of SDF for prevention and treatment of incipient root caries in older adult nursing home residents. METHOD: Four hundred older adult nursing home residents (≥70 years old) with at least one exposed root surface (on teeth 15, 14, 13, 23, 24, or 25) were identified during routine dental examination visits in the domiciliary dental care setting. Eligible patients, who were able to understand the implication of consenting to the study, were invited to participate. Their cleaned root surfaces were randomly allocated to treatment with SDF (Advantage Arrest Silver Diamine Fluoride 38%, Advantage Arrest, LLC, Redmond, OR 97756, USA, Lot 16 152) or with placebo (tap water), each for 1 minute. RESULTS: Of the 400 eligible individuals, 42 declined to participate and two forms were destroyed. The remaining 356 participants (89.0%; mean age 87.7 years) were randomly allocated, with 174 going to the SDF group and 182 to the placebo group. At 1 year, 273 participants (76.7%) were available for assessment: 135 in the SDF group and 138 in the placebo group. By that time, 109 individuals (39.9%) demonstrated root caries progression or regression. Among those 118 (16.7%) of the 708 included root surfaces had developed caries There were no statistically significant differences in the primary outcome related to treatment with SDF or placebo, at either patient or root surface level. CONCLUSION: Based on the finding of this clinical trial, it is concluded that a single SDF application to complement a risk-based preventive programme including fluoride varnish applications did not have a statistically significant additional preventive effect on root caries development in a group of older adult nursing home residents with limited caries activity and cognitive capacity to cooperate in oral care activities.

Salivary levels of five microorganisms of root caries in nursing home elderly: a preliminary investigation.

BACKGROUND: Streptococcus, Bifidobacteria, Lactobacillus and Actinomyces are acidogenic aciduria that may be associated with root caries (RC). The aim of the study was to analyze Streptococcus mutans (S. mutans), Streptococcus sobrinus (S. sobrinus), Bifidobacterium spp., Lactobacillus spp. and Actinomyces naeslundii (A. naeslundii) in the saliva of nursing home elderly, to assess the correlation between bacterial composition and RC for five putative catiogenic organisms. METHODS: In this study, we collected 43 saliva samples and divided into two groups: the root caries group (RCG, n = 21) and the caries-free group (CFG, n = 22). Bacterial DNA was extracted from the saliva samples. The presence and abundance of the five microorganisms were detected by Quantitative real-time PCR (qPCR). Spearman correlation test was performed to evaluate the relationship between the numbers of root decayed filled surfaces (RDFS) and root caries index (RCI) and salivary levels of the bacteria. RESULTS: The salivary levels of S. mutans, S. sobrinus, Bifidobacterium spp. and Lactobacillus spp. were significantly higher in RCG than in CFG (p < 0.05). RDFS and RCI (RDFS/RCI) were positively associated with salivary levels of S. mutans, S. sobrinus and Bifidobacterium spp. (r = 0.658/0.635, r = 0.465/0.420 and r = 0.407/0.406, respectively). No significant differences in presence and amounts of A. naeslundii was observed between the two groups (p > 0.05). CONCLUSION: S. mutans, S. sobrinus and Bifidobacterium spp. in saliva appear to be associated with RC in the elderly. Taken together, the findings indicate that specific salivary bacteria may be involved in the progression of RC.

Caries experience and risk indicators of having decayed teeth among 65-year-olds in Oslo, Norway: a cross-sectional study.

BACKGROUND: Meeting the oral health needs of the increasing population of older adults presents a major challenge in dental care. Knowledge about the oral health status in the young-elderly age group is essential for the planning of future oral health education and prevention programs. The aims of the present study were therefore to investigate the caries experience among 65-year-olds in Oslo, Norway, and to explore associations between having decayed teeth and sociodemographic, behavioural, and biological factors. METHODS: A random sample of 65­year­olds in Oslo answered a questionnaire and underwent clinical and radiographic examinations (n = 457, 52% men and 48% women) at the Research Clinic, Faculty of Dentistry, University of Oslo, between February and December 2019. Primary- and secondary coronal and root caries lesions, root remnants, and missing and restored teeth were recorded. Decayed teeth (DT) were defined as teeth with coronal- and root caries lesions that had progressed into dentine and root remnants, and the DMFT/S scores were calculated. RESULTS: The mean number of teeth was 25 (SD: 4) and the mean DMFT was 19.4 (SD: 4.7). Thirty seven percent of the individuals had at least one decayed tooth (DT > 0), and the mean number of filled teeth (FT) was 16.1 (SD: 5.4). Multivariable logistic regression analysis showed that male gender (OR: 1.8, 95% CI: 1.2-2.8), basic level of education (OR: 1.9, 95% CI: 1.2-2.9), irregular dental attendance (OR: 2.2, 95% CI: 1.0-4.8), and hyposalivation (OR: 2.1, 95% CI: 1.0-4.4) were significant risk indicators for having decayed teeth (DT > 0) (p < 0.05). CONCLUSIONS: In conclusion, 65-year-olds in Oslo had a low average number of decayed and missing teeth, and a high number of restored teeth. Irregular dental attendance and hyposalivation were the strongest risk indicators for having decayed teeth. Based on the present results, it will be important to ensure access to regular dental care and to increase the emphasis on caries preventive measures for individuals with hyposalivation in this age group.

A Co-Association of Streptococcus mutans and Veillonella parvula/dispar in Root Caries Patients and In Vitro Biofilms.

Root caries in geriatric patients is a growing problem as more people are maintaining their natural teeth into advanced age. We determined the levels of various bacterial species previously implicated in root caries disease or health using quantitative real-time PCR in a pilot study of 7 patients with 1 to 4 root caries lesions per person. Levels of 12 different species on diseased roots compared to healthy (contralateral control) roots were measured. Four species were found at significantly higher levels on diseased roots (Streptococcus mutans, Veillonella parvula/dispar, Actinomyces naeslundii/viscosus, and Capnocytophaga granulosa) compared across all plaque samples. The level of colonization by these species varied dramatically (up to 1,000-fold) between patients, indicating different patients have different bacteria contributing to root caries disease. Neither of the two species previously reported to correlate with healthy roots (C. granulosa and Delftia acidovorans) showed statistically significant protective roles in our population, although D. acidovorans showed a trend toward higher levels on healthy teeth (P = 0.08). There was a significant positive correlation between higher levels of S. mutans and V. parvula/dispar on the same diseased teeth. In vitro mixed biofilm studies demonstrated that co-culturing S. mutans and V. parvula leads to a 50 to 150% increase in sucrose-dependent biofilm mass compared to S. mutans alone, depending on the growth conditions, while V. parvula alone did not form in vitro biofilms. The presence of V. parvula also decreased the acidification of S. mutans biofilms when grown in artificial saliva and enhanced the health of mixed biofilms.

Synchrotron radiation analysis of root dentin: the roles of fluoride and calcium ions in hydroxyapatite remineralization.

Although the use of fluoride for root caries control is reported to be effective, the mechanism of maintaining hydroxyapatite is still unclear. This study elucidates the roles of fluoride in the recrystallization of hydroxyapatite, and the impact of calcium to maintain the abundance of hydroxyapatite on acid-challenged root dentin with a novel approach - using synchrotron radiation. Root dentin samples obtained from 40 extracted human premolars were subjected to pH challenge in combination with fluoride treatment. The effect of fluoride on hydroxyapatite regeneration on the root was investigated by using a range of fluoride concentrations (1000-5000 p.p.m.) and the EDTA-chelation technique in vitro. Synchrotron radiation X-ray micro-computed tomography and X-ray absorption spectroscopy were utilized to characterize the chemical composition of calcium species on the surface of prepared samples. The percentage of hydroxyapatite and the relative abundance of calcium species were subsequently compared between groups. The absence of calcium or fluoride prevented the complete remineralization of hydroxyapatite on the surface of early root caries. Different concentrations of fluoride exposure did not affect the relative abundance of hydroxyapatite. Sufficient potency of 1000 p.p.m. fluoride solution in promoting hydroxyapatite structural recrystallization on the root was demonstrated. Both calcium and fluoride ions are prerequisites in a caries-prone environment. Orchestration of F- and Ca2+ is required for structural homeostasis of root dentin during acid attack. Sustainable levels of F- and Ca2+ might thus be a strict requirement in the saliva of the population prone to root caries. Fluoride and calcium contribute to structural homeostasis of tooth root, highlighting that routine fluoride use in combination with calcium replenishment is recommended for maintaining dental health. This study also demonstrates that utilization of synchrotron radiation could provide a promising experimental platform for laboratory investigation especially in the dental material research field.

Streptococcus mutans Gene Expression and Functional Profile in Root Caries: An RNA-Seq Study.

The literature is still scarce on studies describing Streptococcus mutans global gene expression under clinical conditions such as those found on complex biofilms from sound root surfaces (SRS) and carious root surfaces (RC). This study aimed to investigate the S. mutans gene expression and functional profile within the metatranscriptome of biofilms from SRS and from RC in an attempt to identify enriched functional signatures potentially associated with the healthy-to-disease transitioning process. Total RNA was extracted, and prepared libraries (SRS = 10 and RC = 9) were paired-end sequenced using the Illumina HiSeq2500. A read count assigned to each gene of the S. mutans UA159 strain was obtained. Differentially expressed genes (DEG) between SRS and RC were identified using the DESeq2 R package, and weighted gene co-expression network analysis (WGCNA) was performed to explore and identify functional modules related to SRS and RC. We found seventeen DEG between SRS and RC samples, with three overexpressed in RC and related to membrane protein, alanyl-tRNA synthetase, and GTP-binding protein, with the remaining ones overexpressed in SRS samples and related to hypothetical protein, transposon integrase, histidine kinase, putative transporter, bacteriocin immunity protein, response regulator, 6-phospho-beta-galactosidase, purine metabolism, and transcriptional regulator. Key-functional modules were identified for SRS and RC conditions based on WGCNA, being 139 hub genes found on SRS key-module and 17 genes on RC key-module. Functional analysis of S. mutans within the metatranscriptome of biofilms from sound root and from carious root revealed a similar pattern of gene expression, and only a few genes have been differentially expressed between biofilms from SRS and those from root carious lesions. However, S. mutans presented a greater functional abundance in the carious lesion samples. Some functional patterns related to sugar (starch, sucrose, fructose, mannose, and lactose) and heterofermentative metabolisms, to cell-wall biosynthesis, and to acid tolerance stress seem to be enriched on carious root surfaces, conferring ecological advantages to S. mutans. Altogether, the present data suggest that a functional signature may be associated with carious root lesions.