Changes in Caries Risk in a Practice-Based Randomized Controlled Trial.

To demonstrate that Caries Management by Risk Assessment (CAMBRA) can be successfully implemented in dental practice, 30 dentists were recruited to perform a 2-y CAMBRA trial. Twenty-one dentists (18 private practices, 3 community clinics) participated in a randomized, controlled, parallel-arm, double-blind clinical trial with individual-level assignment of 460 participants to standard of care (control) versus active CAMBRA treatment (intervention). Control or active antimicrobial and remineralizing agents were dispensed at baseline and 6-, 12-, 18-, and 24-mo recall visits according to risk level and assigned treatment arm. Primary outcome measure was dentist-determined caries risk level at recall. Among initially high-risk participants, secondary outcomes were recorded disease indicators. Generalized estimating equations were used to fit log-linear models for each outcome while accounting for repeated measurements. At 24 mo, follow-up rates were 34.3% for high-risk participants (32.1% intervention, 37.1% control) and 44.2% for low-risk participants (38.7% intervention, 49.5% control). Among 242 participants classified as high caries risk at baseline (137 intervention, 105 control), a lower percentage of participants remained at high risk in the intervention group (statistically significant at all time points). At 24 mo, 25% in the intervention group and 54% in the control group remained at high risk ( P = 0.003). Among 192 participants initially classified as low risk (93 intervention, 99 control), most participants remained at low risk. At 24 mo, 89% in the intervention group and 71% in the control group were low caries risk ( P = 0.18). The percentage of initially high-risk participants with recorded disease indicators decreased over time in both intervention and control groups, being always lower for the intervention group (statistically significant at the 12- and 18-mo time point). In this practice-based clinical trial, a significantly greater percentage of high-caries-risk participants were classified at a lower risk level after CAMBRA preventive therapies were provided. Most participants initially assessed at low caries risk stayed at low risk (ClinicalTrials.gov NCT01176396).

The Evidence for Caries Management by Risk Assessment (CAMBRA®).

A system for Caries Management by Risk Assessment (CAMBRA®) has been developed in California. The purpose of this article is to summarize the science behind the methodology, the history of the development of CAMBRA, and the outcomes of clinical application. The CAMBRA caries risk assessment (CRA) tool for ages 6 y through adult has been used at the University of California, San Francisco (UCSF), for 14 y, and outcome studies involving thousands of patients have been conducted. Three outcomes assessments, each on different patient cohorts, demonstrated a clear relationship between CAMBRA-CRA risk levels of low, moderate, high, and extreme with cavitation or lesions into dentin (by radiograph) at follow-up. This validated risk prediction tool has been updated with time and is now routinely used at UCSF and in other settings worldwide as part of normal clinical practice. The CAMBRA-CRA tool for 0- to 5-y-olds has demonstrated similar predictive validity and is in routine use. The addition of chemical therapy (antibacterial plus fluoride) to the traditional restorative treatment plan, based on caries risk status, has been shown to reduce the caries increment by about 20% to 38% in high-caries-risk adult patients. The chemical therapy used for high-risk patients is a combination of daily antibacterial therapy (0.12% w/v chlorhexidine gluconate mouth rinse) and twice-daily high-concentration fluoride toothpaste (5,000 ppm F), both for home use. These outcomes assessments provide the evidence to use these CRA tools with confidence. Caries can be managed by adding chemical therapy, based on the assessed caries risk level, coupled with necessary restorative procedures. For high- and extreme-risk patients, a combination of antibacterial and fluoride therapy is necessary. The fluoride therapy must be supplemented by antibacterial therapy to reduce the bacterial challenge, modify the biofilm, and provide prevention rather than continued caries progression.

Caries risk/susceptibility assessment: its value in minimum intervention oral healthcare.

This narrative review describes the intimate connection between minimum intervention (MI) oral healthcare and caries risk/susceptibility assessment (CRA). Indeed CRA is the corner stone of an MI care plan, allowing the determination of the appropriate interventions (non-invasive as well as invasive [restorative]) and recall consultation strategies. Various CRA protocols/models have been developed to assist the oral healthcare practitioner/team in a logical systematic approach to synthesising information about a disease that has a multifactorial aetiology. Despite the criticisms toward the lack of clear-cut validation of the proposed protocols/models, CRA still has great potential to enhance patient care by allowing the oral healthcare practitioner/team and the patient to understand the specific reasons for their caries activity and to tailor their care plans and recall intervals accordingly.

Distinct decalcification process of dentin by different cariogenic organic acids: Kinetics, ultrastructure and mechanical properties.

OBJECTIVES: We studied artificial dentin lesions in human teeth generated by lactate and acetate buffers (pH 5.0), the two most abundant acids in caries. The objective of this study was to determine differences in mechanical properties, mineral density profiles and ultrastructural variations of two different artificial lesions with the same approximate depth. METHODS: 0.05M (pH 5.0) acetate or lactate buffer was used to create 1) 180µm-deep lesions in non-carious human dentin blocks (acetate 130h; lactate 14days); (2) demineralized, ∼180µm-thick non-carious dentin discs (3 weeks). We performed nanoindentation to determine mechanical properties across the hydrated lesions, and micro X-ray computed tomography (MicroXCT) to determine mineral profiles. Ultrastructure in lesions was analyzed by TEM/selected area electron diffraction (SAED). Demineralized dentin discs were analyzed by small angle X-ray scattering (SAXS). RESULTS: Diffusion-dominated demineralization was shown based on the linearity between lesion depths versus the square root of exposure time in either solution, with faster kinetics in acetate buffer. Nanoindentation revealed lactate induced a significantly sharper transition in reduced elastic modulus across the lesions. MicroXCT showed lactate demineralized lesions had swelling and more disorganized matrix structure, whereas acetate lesions had abrupt X-ray absorption near the margin. At the ultrastructural level, TEM showed lactate was more effective in removing minerals from the collagenous matrix, which was confirmed by SAXS analysis. CONCLUSIONS: These findings indicated the different acids yielded lesions with different characteristics that could influence lesion formation resulting in their distinct predominance in different caries activities, and these differences may impact strategies for dentin caries remineralization.

Understanding treatment effect mechanisms of the CAMBRA randomized trial in reducing caries increment.

The Caries Management By Risk Assessment (CAMBRA) randomized controlled trial showed that an intervention featuring combined antibacterial and fluoride therapy significantly reduced bacterial load and suggested reduced caries increment in adults with 1 to 7 baseline cavitated teeth. While trial results speak to the overall effectiveness of an intervention, insight can be gained from understanding the mechanism by which an intervention acts on putative intermediate variables (mediators) to affect outcomes. This study conducted mediation analyses on 109 participants who completed the trial to understand whether the intervention reduced caries increment through its action on potential mediators (oral bacterial load, fluoride levels, and overall caries risk based on the composite of bacterial challenge and salivary fluoride) between the intervention and dental outcomes. The primary outcome was the increment from baseline in decayed, missing, and filled permanent surfaces (ΔDMFS) 24 mo after completing restorations for baseline cavitated lesions. Analyses adjusted for baseline overall risk, bacterial challenge, and fluoride values under a potential outcome framework using generalized linear models. Overall, the CAMBRA intervention was suggestive in reducing the 24-mo DMFS increment (reduction in ΔDMFS: -0.96; 95% confidence interval [CI]: -2.01 to 0.08; P = 0.07); the intervention significantly reduced the 12-mo overall risk (reduction in overall risk: -19%; 95% CI, -7 to -41%;], P = 0.005). Individual mediators, salivary log10 mutans streptococci, log10 lactobacilli, and fluoride level, did not represent statistically significant pathways alone through which the intervention effect was transmitted. However, 36% of the intervention effect on 24-mo DMFS increment was through a mediation effect on 12-mo overall risk (P = 0.03). These findings suggest a greater intervention effect carried through the combined action on multiple aspects of the caries process rather than through any single factor. In addition, a substantial portion of the total effect of the CAMBRA intervention may have operated through unanticipated or unmeasured pathways not included among the potential mediators studied.

Maternal oral bacterial levels predict early childhood caries development.

OBJECTIVE: To calculate the association of maternal salivary bacterial challenge (mutans streptococci [MS] and lactobacilli [LB]) from pregnancy through 24 months' postpartum with child caries incidence (≥1 cavitated or restored teeth) at 36 months. MATERIALS & METHODS: Dental, salivary bacterial, sociodemographic, and behavioral measures were collected at three- to six-month intervals from a birth cohort of low-income Hispanic mother-child dyads (N = 243). We calculated the relative child caries incidence, adjusted for confounding, following higher maternal challenge of MS (>4500 colony-forming units per milliliter of saliva [CFU/mL]) and LB (>50 CFU/mL) based on multivariable models. RESULTS: Salivary MS and LB levels were greater among mothers of caries-affected children versus caries-free children. Mothers with higher salivary MS challenge were more likely to have MS-positive children (>0 CFU/mL), but maternal LB challenge was not a statistically significant predictor of child LB-positive status. Adjusting for sociodemographics, feeding and care practices, and maternal dental status, higher maternal salivary challenge of both MS and LB over the study period predicted nearly double the child caries incidence versus lower MS and LB (cumulative incidence ratio: 1.9; 95% confidence interval: 1.1, 3.8). CONCLUSION: Maternal salivary bacterial challenge not only is associated with oral infection among children but also predicts increased early childhood caries occurrence.

Minimal intervention dentistry: part 3. Paediatric dental care--prevention and management protocols using caries risk assessment for infants and young children.

Recent increases in caries prevalence in young children throughout the world highlight the need for a simple but effective infant oral care programme. This programme needs to include a medical disease prevention management model with an early establishment of a dental home and a treatment approach based on individual patient risk. This article presents an updated approach with practical forms and tools based on the principles of caries management by risk assessment, CAMBRA. This method will aid the general practitioner to develop and maintain a comprehensive protocol adequate for infant and young children oral care visits. Perinatal oral health is vitally important in preventing early childhood caries (ECC) in young children. Providing dental treatment to expectant mothers and their young children in a 'dual parallel track' is an effective innovative strategy and an efficient practice builder. It promotes prevention rather than intervention, and this may be the best way to achieve long-lasting oral health for young patients. General dental practice can adopt easy protocols that will promote early preventive visits and anticipatory guidance/counselling rather than waiting for the need for restorative treatment.

Minimal intervention dentistry: part 1. From 'compulsive' restorative dentistry to rational therapeutic strategies.

The concept of minimal intervention dentistry is based on all the factors that affect the onset and progression of disease and therefore integrates concepts of prevention, control and treatment. The field of minimal intervention dentistry is wide, including the detection of lesions as early as possible, the identification of risk factors (risk assessment) and the implementation of preventive strategies and health education for the patient. When the effects of the disease are present, in the form of a carious lesion, other therapeutic strategies are required, but in this case the least invasive solutions should be chosen, for example remineralisation, therapeutic sealants and restorative care aimed at conserving the maximum amount of sound tissue. This article aims to enlighten dental practitioners as to the foundations of minimal intervention dentistry in order to help them in the implementation of modern concepts into everyday clinical practice.

The role of remineralizing and anticaries agents in caries management.

The first ICNARA conference (International Conference on Novel Anticaries and Remineralizing Agents) was held in Chile in January, 2008, and the proceedings were published in Advances in Dental Research (Volume 21, 2009). That issue of Advances summarized the state of the science and set a research agenda for the future for two key components of caries management, namely, antibacterial agents and remineralizing agents. The second conference (ICNARA 2, January 2012) provided an update on science and new directions for research and clinical practice. Over the past decade, renewed efforts have been made across the world to establish proven methods of caries risk assessment and to provide direction for improved methods of caries management based upon risk levels. Evidence-based caries risk assessment tools are now available. The need for improved therapy to reduce the bacterial challenge that initiates the caries process, and to enhance remineralization, is now very clear. Fluoride therapy alone is insufficient to control the caries process in high-risk individuals. New remineralizing and anticaries products and new delivery systems are in development, and ICNARA 2 presents future technology for the management of dental caries.

Strategic protein target analysis for developing drugs to stop dental caries.

Dental caries is the most common disease to cause irreversible damage in humans. Several therapeutic agents are available to treat or prevent dental caries, but none besides fluoride has significantly influenced the disease burden globally. Etiologic mechanisms of the mutans group streptococci and specific Lactobacillus species have been characterized to various degrees of detail, from identification of physiologic processes to specific proteins. Here, we analyze the entire Streptococcus mutans proteome for potential drug targets by investigating their uniqueness with respect to non-cariogenic dental plaque bacteria, quality of protein structure models, and the likelihood of finding a drug for the active site. Our results suggest specific targets for rational drug discovery, including 15 known virulence factors, 16 proteins for which crystallographic structures are available, and 84 previously uncharacterized proteins, with various levels of similarity to homologs in dental plaque bacteria. This analysis provides a map to streamline the process of clinical development of effective multispecies pharmacologic interventions for dental caries.

Clinical efficacy and effects of xylitol wipes on bacterial virulence.

The aim of the study was to investigate whether xylitol-wipe use in young children prevented caries by affecting bacterial virulence. In a double-blinded randomized controlled clinical trial, 44 mother-child pairs were randomized to xylitol-wipe or placebo-wipe groups. Salivary mutans streptococci levels were enumerated at baseline, 6 months, and one year. Ten mutans streptococci colonies were isolated and genotyped from each saliva sample. Genotype-colonization stability, xylitol sensitivity, and biofilm formation of these isolates were studied. Despite a significant reduction in new caries at one year in the xylitol-wipe group, no significant differences were found between the two groups in levels of mutans streptococci. Children in the xylitol-wipe group had significantly fewer retained genotypes (p = 0.06) and more transient genotypes of mutans streptococci (p = 0.05) than those in the placebo-wipe group. At one year, there was no significant difference in the prevalence of xylitol-resistant genotypes or in biofilm formation ability of mutans streptococci isolates between the two groups. The mechanism of the caries-preventive effect of xylitol-wipe use may be related to the stability of mutans streptococci colonization. Further studies with genomic characterization methods are needed to determine specific gene(s) that account for the caries-preventive effect of xylitol.

Effects of xylitol wipes on cariogenic bacteria and caries in young children.

The aim of the study was to investigate the efficacy of the use of xylitol-containing tooth-wipes in preventing dental caries in young children. In a double-blinded randomized controlled clinical trial, 44 mothers with active caries and their 6- to 35-month-old children were randomized to xylitol-wipe or placebo-wipe groups. The children's caries scores were recorded at baseline and 1 year. Salivary levels of mutans streptococci and lactobacilli were enumerated at baseline, 3, 6, and 12 months. Data were analyzed by intent-to-treat modeling with imputation for caries lesions and a linear mixed-effect model for bacterial levels. Significantly fewer children in the xylitol-wipe group had new caries lesions at 1 year compared with those in the placebo-wipe group (P < 0.05). No significant differences between the two groups were observed in levels of mutans streptococci and lactobacilli at all time-points. Daily xylitol-wipe application significantly reduced the caries incidence in young children as compared with wipes without xylitol, suggesting that the use of xylitol wipes may be a useful adjunct for caries control in infants (Clinicaltrials.gov registration number CT01468727).

A randomized clinical trial of anticaries therapies targeted according to risk assessment (caries management by risk assessment).

This randomized parallel group clinical trial assessed whether combined antibacterial and fluoride therapy benefits the balance between caries pathological and protective factors. Eligible, enrolled adults (n = 231), with 1-7 baseline cavitated teeth, attending a dental school clinic were randomly assigned to a control or intervention group. Salivary mutans streptococci (MS), lactobacilli (LB), fluoride (F) level, and resulting caries risk status (low or high) assays were determined at baseline and every 6 months. After baseline, all cavitated teeth were restored. An examiner masked to group conducted caries exams at baseline and 2 years after completing restorations. The intervention group used fluoride dentifrice (1,100 ppm F as NaF), 0.12% chlorhexidine gluconate rinse based upon bacterial challenge (MS and LB), and 0.05% NaF rinse based upon salivary F. For the primary outcome, mean caries increment, no statistically significant difference was observed (24% difference between control and intervention groups, p = 0.101). However, the supplemental adjusted zero-inflated Poisson caries increment (change in DMFS) model showed the intervention group had a statistically significantly 24% lower mean than the control group (p = 0.020). Overall, caries risk reduced significantly in intervention versus control over 2 years (baseline adjusted generalized linear mixed models odds ratio, aOR = 3.45; 95% CI: 1.67, 7.13). Change in MS bacterial challenge differed significantly between groups (aOR = 6.70; 95% CI: 2.96, 15.13) but not for LB or F. Targeted antibacterial and fluoride therapy based on salivary microbial and fluoride levels favorably altered the balance between pathological and protective caries risk factors.

Near-UV laser treatment of extrinsic dental enamel stains.

BACKGROUND AND OBJECTIVES: The selective ablation of extrinsic dental enamel stains using a 400-nm laser is evaluated at several fluences for completely removing stains with minimal damage to the underlying enamel. STUDY DESIGN/MATERIALS AND METHODS: A frequency-doubled Ti:sapphire laser (400-nm wavelength, 60-nanosecond pulse duration, 10-Hz repetition rate) was used to treat 10 extracted human teeth with extrinsic enamel staining. Each tooth was irradiated perpendicular to the surface in a back-and-forth motion over a 1-mm length using an ∼300-µm-diam 10th-order super-Gaussian beam with fluences ranging from 0.8 to 6.4 J/cm(2) . Laser triangulation determined stain depth and volume removed by measuring 3D surface images before and after irradiation. Scanning electron microscopy evaluated the surface roughness of enamel following stain removal. Fluorescence spectroscopy measured spectra of unbleached and photobleached stains in the spectral range of 600-800 nm. RESULTS: Extrinsic enamel stains are removed with laser fluences between 0.8 and 6.4 J/cm(2) . Stains removed on sound enamel leave behind a smooth enamel surface. Stain removal in areas with signs of earlier cariogenic acid attacks resulted in isolated and randomly located laser-induced, 50-µm-diam enamel pits. These pits contain 0.5-µm diam, smooth craters indicative of heat transfer from the stain to the enamel and subsequent melting and water droplet ejection. Ablation stalling of enamel stains is typically observed at low fluences (<3 J/cm(2) ) and is accompanied by a drastic reduction in porphyrin fluorescence from the Soret band. CONCLUSION: Laser ablation of extrinsic enamel stains at 400 nm is observed to be most efficient above 3 J/cm(2) with minimal damage to the underlying enamel. Unsound underlying enamel is also observed to be selectively removed after irradiation.

Effect of sublethal CO2 laser irradiation on gene expression of streptococcus mutans immobilized in a biofilm.

Streptococcus mutans colonizing on tooth surfaces is one of the major causative agents of human dental caries. Despite numerous studies conducted on lasers and oral tissue interactions, little is known about the effect of laser energy on S. mutans gene expression in a biofilm form. The aim of this study was to investigate the effect of sublethal energies of CO(2) laser on biofilm and gene expression of the oral bacteria S. mutans immobilized in biofilm. S. mutans biofilm was irradiated with CO(2) laser. Vitality and construction of the biofilm were observed by confocal laser scanning microscopy and scanning electron microscopy. The effect of laser irradiation on gene expression was evaluated by DNA microarray. CO(2) laser irradiation had a dose effect on the viability of S. mutans immobilized in biofilm. A nonsignificant lethal effect was observed at 31 J/cm(2) while at higher energy of 70 and 144 J/cm(2) an antibacterial effect was recorded. The mode of antibacterial action seems to be from the inner layers toward the outer layer of the biofilm, indicating the influence of the surface on the killing effect. At 31 J/cm(2), microarray analysis indicated a moderate effect on S. mutans gene expression due to CO(2) laser irradiation, mainly down-regulating genes related to bacterial stress response. In conclusion, laser irradiation at sublethal energy had an effect on gene expression of S. mutans.

Horizontal transmission of mutans streptococci in children.

It has not been established whether transmission of mutans streptococci occurs between unrelated children older than 4 years of age. The aim of the study was to investigate the possible transmission of mutans streptococci genotypes from child to child in kindergarten. We studied 96 children (ages 5-6 yrs) in three San Francisco Bay Area public schools. Mutans streptococci colonies from each child were isolated from selective culture on Mitis Salivarius Sucrose Bacitracin agar. We used arbitrary primed polymerase chain reactions to determine the mutans streptococci genotypes. Two children (not siblings) in each of the three schools (6%) shared an identical amplitype of S. mutans, unique to each pair. The 19 S. sobrinus amplitypes were found in 12 children, and all were unique to each child. The presence of matching genotypes of S. mutans demonstrates horizontal transmission of this species between unrelated children aged 5-6 years.

Dental caries: a dynamic disease process.

Abstract Dental caries is a transmissible bacterial disease process caused by acids from bacterial metabolism diffusing into enamel and dentine and dissolving the mineral. The bacteria responsible produce organic acids as a by-product of their metabolism of fermentable carbohydrates. The caries process is a continuum resulting from many cycles of demineralization and remineralization. Demineralization begins at the atomic level at the crystal surface inside the enamel or dentine and can continue unless halted with the end-point being cavitation. There are many possibilities to intervene in this continuing process to arrest or reverse the progress of the lesion. Remineralization is the natural repair process for non-cavitated lesions, and relies on calcium and phosphate ions assisted by fluoride to rebuild a new surface on existing crystal remnants in subsurface lesions remaining after demineralization. These remineralized crystals are acid resistant, being much less soluble than the original mineral.