Recommendations on Topical Fluoride Usage for Caries Management in East Asia.

Dental caries is a widespread oral health issue in Asia, affecting an estimated 30% to 90% of children and adults. Many caries cases remain untreated, resulting in pain and infection. In response, the Asian Academy of Preventive Dentistry (AAPD) emphasises comprehensive caries management and organised a fluoride workshop at the 15th International Conference of the AAPD in 2023. The AAPD invited a group of experts to form a fluoride working group to review existing literature and develop fluoride recommendations for stakeholders across Asian countries and regions. The working group assessed caries risk and identified commonly used topical fluoride products for home care, professional, and community settings in Asia. The working group concluded that fluoride is a safe and highly effective strategy to reduce caries prevalence and incidence. The working group provided key recommendations based on successful regional caries management practices: (1) use topical fluoride for prevention and control of dental caries; (2) encourage the use of fluoride toothpaste with a concentration of at least 1,000 ppm for effective caries reduction; (3) advise a 0.05% fluoride mouth rinse as soon as children can spit it out to prevent early childhood caries; (4) deliver professionally administered fluoride, such as 5% sodium fluoride varnish, 2% fluoride gel, or 1.23% acidulated phosphate fluoride preparations, to decrease dental caries in at-risk individuals; and (5) apply 38% silver diamine fluoride to arrest cavitated caries. These recommendations aim to help practitioners, health care providers, and parents/caregivers make informed decisions about fluoride use as part of comprehensive oral health care in the region.

Dental restorative materials containing quaternary ammonium compounds have sustained antibacterial action.

BACKGROUND: This narrative review addresses dental restorative materials with sustained antibacterial action, especially those containing quaternary ammonium compounds. Secondary caries occurs around restorations, causing further loss of mineral and breakdown of the restoration. Lesions adjacent to restorations account for more than 40% of needed restorations. Restorative materials with antibacterial properties will potentially solve this problem. TYPES OF STUDIES REVIEWED: Several groups are researching composite restorative materials that incorporate antibacterial agents. These agents are mostly exhausted over time. Newer studies involve materials that incorporate antibacterial microparticles that remain active and do not leach out. RESULTS: One such antibacterial agent, quaternary ammonium coupled with inorganic silica into minute particles (QASi), has been studied in the laboratory and in humans. QASi particles incorporated into dental materials retain their antibacterial action over time without leaching or loss of activity. A clinical in situ study in humans using dental composite containing QASi resulted in highly significantly less demineralization in the adjacent enamel than the control composite material. CONCLUSIONS AND PRACTICAL IMPLICATIONS: Dental restorative materials that contain QASi have sustained antibacterial properties, have mechanical properties comparable to those of presently marketed materials, and have been cleared by the US Food and Drug Administration. Clinical studies have shown that composites incorporating QASi have the potential to markedly reduce the occurrence of caries around restorations. Because caries around restorations is a major problem, restorative materials with sustained antibacterial properties will have an important effect in reducing secondary caries around restorations.

A Comparison of Four Caries Risk Assessment Methods.

Introduction: Caries risk assessment (CRA) is essential as the basis for successful management of dental caries. Of the many published CRA tools, four well-known ones are CAMBRA, Cariogram, American Dental Association (ADA), and American Academy of Pediatric Dentistry (AAPD) CRAs. The predictive accuracy of CAMBRA and Cariogram CRA tools have been examined in clinical outcomes studies in thousands of patients and the tools are widely used all over the world. The purpose of the present paper is three-fold, namely (1) to briefly review, compare and contrast these four CRA methods, (2) to provide a concise method for CRA introducing a quantitative component to the CAMBRA forms (CAMBRA 123), and (3) to guide the choice of CRA methods that will support caries management decisions. Comparison of Caries Risk Assessment Methods: In the present evaluation, the above-mentioned four CRA methods for ages 0-6 years and 6 years-adult were compared using 26 hypothetical patients (13 per age group). Comparison results show that Cariogram and CAMBRA categorized patients into identical risk categories. Each of the ADA and AAPD tools gave different results than CAMBRA and Cariogram in several comparison examples. CAMBRA 123 gave the same caries risk level results as the Cariogram and the CAMBRA methods for all hypothetical patients for both age groups. Conclusions: Both the Cariogram and the CAMBRA CRA methods are equally useful for identifying the future risk of dental caries. CAMBRA 123 shows promise as an easy-to-use quantitative method for CRA in clinical practice. The health care providers will be the ones to decide which CRA method will allow them to establish individualized, successful caries management therapies and how to combine these for the best care of their patients.

Evidence-Based Caries Management for All Ages-Practical Guidelines.

Introduction: The purpose of the present paper is to provide step-by-step guidelines for dental healthcare providers to manage dental caries based upon caries risk assessment (CRA) for ages 0-6 years and 6 years through adult. The manuscript reviews and updates the CAMBRA (caries management by risk assessment) system which includes CRA and caries management recommendations that are guided by the assessed risk level. Caries Risk Assessment: CAMBRA CRA tools (CRAs) have been evaluated in several clinical outcomes studies and clinical trials. Updated CAMBRA CRAs for ages 0-6 years and 6 years through adult are provided. These CRAs have been refined by the addition of a quantitative method that will aid the health care provider in determining the caries risk of individuals. Caries Management Based Upon Risk Assessment: Guidelines for individualized patient care are provided based upon the caries risk status, results of clinical exams and responses of the patient to questions in the CRA. These guidelines are based upon successful outcomes documented in several clinical outcomes studies and clinical trials. The paper includes a review of successful caries management procedures for children and adults as previously published, with additional emphasis on correct use of silver diamine fluoride (SDF) for children. The caries management plan for each individual is based upon reducing the caries risk factors and enhancing the protective factors with the additional aid of behavior modification. Beneficially altering the caries balance is coupled with minimal intervention restorative dentistry, if appropriate. These methods are appropriate for the management of dental caries in all patients.

Exposure of Streptococcus mutans and Streptococcus sanguinis to blue light in an oral biofilm model.

The potential anti-cariogenic effect of blue light was evaluated using an oral biofilm model. Two species, Streptococcus mutans and Streptococcus sanguinis, were cultivated ex vivo on bovine enamel blocks for 24 h, either separately or mixed together, then exposed to blue light (wavelengths 400-500 nm) using 112 J/cm2. Twenty four or 48 h after exposure to light the biofilm structure and biomass were characterized and quantified using SEM and qPCR, respectively. Bacterial viability was analyzed by CLSM using live/dead bacterial staining. Gene expression was examined by RT-qPCR. After exposure to light, S. mutans biomass in mono-species biofilm was increased mainly by dead bacteria, relative to control. However, the bacterial biomass of S. mutans when grown in mixed biofilm and of S. sanguinis in mono-species biofilm was reduced after light exposure, with no significant change in viability when compared to control. Furthermore, when grown separately, an upregulation of gene expression related to biofilm formation of S. mutans, and downregulation of similar genes of S. sanguinis, were measured 24 h after exposure to blue light. However, in mixed biofilm, a downregulation of those genes in both species was observed, although not significant in S. mutans. In conclusion, blue light seems to effectively alter the bacterial biomass by reducing the viability and virulence characteristics in both bacterial species and may promote the anti-cariogenic balance between them, when grown in a mixed biofilm. Therefore, exposure of oral biofilm to blue light has the potential to serve as a complementary approach in preventive dentistry.

Efficacy of an adenosine triphosphate meter for evaluating caries risk in clinical dental practice.

BACKGROUND: Adenosine triphosphate bioluminescence (ATP-B) readings have been proposed as markers of caries risk. ATP readings may indicate bacteria or oral streptococci activity in microbial plaque. The authors of this study aimed to evaluate whether readings using a commercial ATP meter (CariScreen Testing Meter, Oral BioTech) are significantly different for patients with low, moderate, and high caries risk in the Caries Management by Risk Assessment Practice-Based Research Network study. METHODS: Twenty practice-based research network dentists enrolled 460 patients; 271 returned for 2 or more semiannual follow-up visits over 2 years. Dentists were trained and calibrated to perform ATP-B testing and caries risk assessment (CRA) using established protocols. ATP-B readings were compared via CRA category (low, moderate, high). Generalized estimating equations were used to compare the risk of experiencing incident clinical outcomes (newly recorded decayed, missing, or restored tooth surfaces and CRA disease indicators) according to ATP-B reading at prior patient visits (≥ 1,500 versus < 1,500 relative light units). RESULTS: Median ATP-B readings did not differ statistically significantly by clinician-assessed caries risk level (low, 2,323; moderate, 2,940; high, 3,217; P = .65). Adjusted for patient demographics and trial intervention assignment, higher readings were not associated with newly developed decayed, missing, or restored tooth surface (relative risk, 1.57; 95% confidence interval, 0.55 to 4.45) or disease indicators (relative risk, 1.08; 95% confidence interval, 0.85 to 1.37) at the following visit, whereas clinician-assessed caries risk level was strongly associated. CONCLUSIONS: ATP-B readings poorly predicted caries risk and future clinical outcomes. CRA incorporating multiple risk, protective, and disease indicators has superior predictive performance. PRACTICAL IMPLICATIONS: The findings of this study do not provide evidence supporting the use of ATP-B to predict caries risk.

Caries Management by Risk Assessment: Results from a Practice-Based Research Network Study.

Thirty dentists with clinical practices outside of a university setting were trained and calibrated successfully in DMFS and ICDAS-scoring. This randomized, controlled, parallel-arm, double-blind 2-year clinical trial with individual-level caries risk assignment of 460 patients to standard of care as control versus active CAMBRA treatment as intervention demonstrated that caries risk level, as well as caries disease indicators, were significantly reduced in the CAMBRA intervention group compared to the controls at all recall time points.

The Adaptive Morphology of Bacillus subtilis Biofilms: A Defense Mechanism against Bacterial Starvation.

Biofilms are commonly defined as accumulations of microbes, embedded in a self-secreted, polysaccharide-rich extra-cellular matrix. This study aimed to characterize specific morphological changes that occur in Bacillus subtilis biofilms under nutrient-limiting growth conditions. Under varying levels of nutrient depletion, colony-type biofilms were found to exhibit different rates of spatial expansion and green fluorescent protein production. Specifically, colony-type biofilms grown on media with decreased lysogeny broth content exhibited increased spatial expansion and more stable GFP production over the entire growth period. By modeling the surface morphology of colony-type biofilms using confocal and multiphoton microscopy, we analyzed the appearance of distinctive folds or "wrinkles" that form as a result of lysogeny broth content reduction in the solid agar growth media. When subjected to varying nutritional conditions, the channel-like folds were shown to alter their morphology; growth on nutrient-depleted media was found to trigger the formation of large and straight wrinkles connecting the colony core to its periphery. To test a possible functional role of the formed channels, a fluorescent analogue of glucose was used to demonstrate preferential native uptake of the molecules into the channels' interiors which supports their possible role in the transport of molecules throughout biofilm structures.

Change of salivary fluoride level with intake of fluoride releasing lozenges: A pilot study.

AIM: Long-term, low-level fluoride concentrations in saliva are highly effective in caries prevention and remineralization. The aim of the present two-phased study was to test whether fluoride-releasing lozenges compared to placebo significantly raise salivary fluoride levels above baseline achieved by 1100 ppm fluoride toothpaste in a double-blind, crossover pilot study. METHODS: In phase 1, a four-arm crossover basic study, four participants used one dissolvable lozenge with .25, 0.5, 1 or 1.5 mg fluoride for 1 hour. In phase 2, the three-arm crossover main study, 11 participants used three lozenges per day for 1 hour for 1 week, establishing long-term salivary fluoride levels dissolving 0 (control), 0.5 and 1.5 mg fluoride lozenges. Saliva was collected at baseline; during lozenge use; 5, 15, 30, and 60 minutes later; and early the next morning. Salivary fluoride levels were determined by laboratory diffusion analysis. RESULTS: In phase 1, 5 minutes after using one lozenge, salivary fluoride levels were above baseline (0.03 ppm), reaching 0.13 ± 0.19 ppm for the 0.25 mg and 0.73 ± 0.75 ppm for the 1.5 mg fluoride lozenge, dropping to baseline after 60 minutes. In phase 2, after 1 week use of 0.5 and 1.5 mg lozenges, respectively, for the 0.5 mg lozenge for 15 minutes and the 1.5 mg lozenge 30 minutes after use, the salivary levels were significantly higher than baseline/control (0.02 ppm). During 1-hour lozenge use, fluoride levels >0.1 ppm were consistently achieved. CONCLUSIONS: Fluoride lozenges achieved elevated salivary fluoride levels during use, but only for short periods after use.

Integrating Caries Management by Risk Assessment (CAMBRA) and Prevention Strategies Into the Contemporary Dental Practice.

In the past, the dental profession has adhered to a rigid tenet: remove decay from a tooth and then restore, a mindset that has been proverbially dubbed as "drill and fill." Today, dental caries is recognized as an infectious disease that affects children and adults throughout life. The philosophy of CAries Management By Risk Assessment, or CAMBRA®, represents a paradigm shift. The CAMBRA concept provides the dentist with scientific, evidence-based solutions with which to approach treatment of dental caries disease. This article reviews the current understanding of the caries balance, the process of demineralization and remineralization of tooth structure, caries risk assessment, and the different levels of caries risk. Adequate treatment protocols specifically related to the remineralization of non-cavitated lesions and CAMBRA validation studies are discussed.

Calibration of dentists for Caries Management by Risk Assessment Research in a Practice Based Research Network - CAMBRA PBRN.

BACKGROUND: To prove that Caries Management by Risk Assessment (CAMBRA) can be successfully implemented in dental practices outside of the university setting, dentists in the San Francisco Bay Area (CA) were approached to participate in a Practice Based Research Network (PBRN) study. The overall goal of the CAMBRA-PBRN study was to recruit 30 dentists to perform a two-year study involving approximately 900 patients. Goal of the calibration study was to standardize and calibrate dentists potentially participating in the CAMBRA-PBRN study. METHODS: To minimize inter-examiner variability in data collection, including classification of carious lesions and recording of existing restorations, participating dentists were trained and calibrated in accurate DMFS (decayed, missing, filled surfaces) charting. Dentists were also trained and calibrated to diagnose and differentiate between sound surfaces and non-cavitated caries lesions (International Caries Detection and Assessment - ICDAS scores 1 and 2) for posterior occlusal surfaces. Thirty dentists were calibrated to a single gold standard examiner (BJ) during 6 calibration sessions, between 2011 and 2014. Kappa statistics were used to determine inter-examiner reliability on 13 or more patients, aged 12-63 (average age 38 ± 15 years), per examiner during each session, resulting in 94 patient encounters over the course of all 6 sessions. To participate in the main study, examiners needed to achieve a minimum required kappa of 0.75. During the calibration process, examiners scored between 1036 and 2220 tooth surfaces. RESULTS: The kappa values (unweighted kappa) of the participating dentists compared to the gold standard examiner ranged from 0.75 to 0.90, with an average kappa of 0.84 ± 0.03. 90% of the examiners achieved overall kappa values above 0.8. However, separate reliability for assessment of non-cavitated lesions, as in other studies, was lower (0.55 ± 0.15). Multiple subcategories were evaluated. All dentists reached sufficient reliability values to proceed into the study; nevertheless, one dentist discontinued with the study due to scheduling conflicts. CONCLUSIONS: The high inter-examiner reliability results have shown that dentists who work in primarily non-research based practices can be effectively standardized and calibrated in data collection, based on specific guidelines created to anticipate potential research study scenarios.

MI Varnish and MI Paste Plus in a caries prevention and remineralization study: a randomized controlled trial.

OBJECTIVES: White spot lesions (WSLs) are a complication of orthodontic therapy. This study investigated the effect of MI (minimally invasive) Paste Plus (MIPP) and MI Varnish (MIV) on WSLs in orthodontic patients during a 12-month, randomized, single-blind, prospective, standard-of-care controlled clinical trial. MATERIALS AND METHODS: Forty subjects, recruited from the UCSF School of Dentistry Orthodontics Clinic, were randomly assigned to the experimental (twice-daily 1100 ppm fluoride toothpaste, daily MIPP, quarterly MIV application) or control group (twice-daily 1100 ppm fluoride toothpaste, fluoride rinse recommendation). Facial surfaces of incisors, canines, and first bicuspids were evaluated at baseline, 3, 6, and 12 months using the enamel decalcification index (EDI) and the international caries detection and assessment system (ICDAS). RESULTS: Findings from 37 subjects are reported. At 12 months, teeth receiving experimental treatment were at lower but not significantly different odds of increased EDI scores (odds ratio, OR 0.63; intra-patient cluster-adjusted 95% CI 0.43, 1.18) and not associated with increased ICDAS scores (OR 0.99; 95% CI 0.64, 1.54). There was no statistically significant difference in mean patient-level EDI sum (experimental group 40.2; control 41.3; t test p = 0.80), ICDAS score (experimental 22.3; control 22.6; Mann-Whitney U test p = 0.80), or percentage of scored surfaces with ICDAS > 0 (experimental 54.6%; control 55.2%; t test p = 0.88). Salivary fluoride levels were significantly higher at 12 months for the experimental than for the control group (0.20 ± 0.26 versus 0.04 ± 0.04 ppm, Mann-Whitney U test p < 0.01). CONCLUSIONS: Applying daily MIPP and quarterly MIV resulted in no statistically significant differences in EDI sum and ICDAS scores. Higher salivary fluoride levels in the experimental group suggest that MIPP and MIV effectively deliver fluoride when used clinically. CLINICAL RELEVANCE: Daily MIPP and quarterly MIV applications do not appear to reduce significantly WSLs incidence during fixed orthodontic treatment.

Bacillus subtilis Biofilm Development - A Computerized Study of Morphology and Kinetics.

Biofilm is commonly defined as accumulation of microbes, embedded in a self-secreted extra-cellular matrix, on solid surfaces or liquid interfaces. In this study, we analyze several aspects of Bacillus subtilis biofilm formation using tools from the field of image processing. Specifically, we characterize the growth kinetics and morphological features of B. subtilis colony type biofilm formation and compare these in colonies grown on two different types of solid media. Additionally, we propose a model for assessing B. subtilis biofilm complexity across different growth conditions. GFP-labeled B. subtilis cells were cultured on agar surfaces over a 4-day period during which microscopic images of developing colonies were taken at equal time intervals. The images were used to perform a computerized analysis of few aspects of biofilm development, based on features that characterize the different phenotypes of B. subtilis colonies. Specifically, the analysis focused on the segmented structure of the colonies, consisting of two different regions of sub-populations that comprise the biofilm - a central "core" region and an "expanding" region surrounding it. Our results demonstrate that complex biofilm of B. subtillis grown on biofilm-promoting medium [standard lysogeny broth (LB) supplemented with manganese and glycerol] is characterized by rapidly developing three-dimensional complex structure observed at its core compared to biofilm grown on standard LB. As the biofilm develops, the core size remains largely unchanged during development and colony expansion is mostly attributed to the expansion in area of outer cell sub-populations. Moreover, when comparing the bacterial growth on biofilm-promoting agar to that of colonies grown on LB, we found a significant decrease in the GFP production of colonies that formed a more complex biofilm. This suggests that complex biofilm formation has a diminishing effect on cell populations at the biofilm core, likely due to a combination of reduced metabolic rate and increased levels of cell death within this region.

Pediatric Caries Risk Assessment as a Predictor of Caries Outcomes.

PURPOSE: To determine cumulative dental treatment experience in a retrospective clinical cohort, according to baseline caries risk assessment (CRA) information. METHODS: Evaluated were electronic records from a university pediatric dental clinic (2009 to 2014) of new, six- to 72- month-old patients who were not treated under sedation or general anesthesia (N equals 750). The mean number of teeth restored or extracted (two-year total and omitting the first 190 days post-baseline to discount initial treatment needs) was compared by baseline CRA category and CRA items (caries risk indicators, protective items, and clinical disease indicators). RESULTS: The CRA category was associated with mean treated teeth over two years (low equals 0.53, moderate equals 1.02, high/extreme equals 4.47) and post 190 days (low equals 0.51, moderate equals 0.89, high/extreme equals 2.11). Any treatment probability was greatest for high/extreme-risk children but not statistically significantly different between low- and moderate-risk. Age-standardized means were greater for all individual baseline clinical indicators and most risk indicators, but lower for most protective items (not statistically significantly for all items). Clinical indicators were the strongest outcome correlates. CONCLUSIONS: In this population, baseline risk information was associated with clinical outcomes. CRA can help identify patients needing more intensive caries prevention.

Increased public reimbursement for prophylactic visits with dentists associated with increased receipt of preventive dental services in children.

OBJECTIVE: To determine whether higher reimbursement for children's preventive dentistry correlates with greater utilization of preventive dental care. METHODS: A cross-sectional analysis of National Survey of Children's Health 2011/2012 was conducted, combined with state Medicaid reimbursement rates for preventive dentistry. Analyses included prevalence, unadjusted odds ratios, and multivariable logistic regression for receipt of preventive dental services. RESULTS: Of all surveyed American children 1-17 years, almost 20 percent had not received preventive dental care in prior year; this percentage is even higher in those with public insurance. Each $10 increase in state reimbursement was associated with a 17 percent decrease in odds of children not receiving preventive services. CONCLUSIONS: Higher state reimbursement for preventive services may increase children's receipt of preventive dental care.

Caries Risk Assessment Item Importance: Risk Designation and Caries Status in Children under Age 6.

BACKGROUND: Caries risk assessment (CRA) is widely recommended for dental caries management. Little is known regarding how practitioners use individual CRA items to determine risk and which individual items independently predict clinical outcomes in children under age 6-years. OBJECTIVES: Assess the relative importance of pediatric CRA items in dental providers' decision-making regarding patient risk and in association with clinically evident caries, cross-sectionally and longitudinally. METHODS: CRA information was abstracted retrospectively from electronic patient records of children initially ages 6-72 months at a university pediatric dentistry clinic (N=3810 baseline; N=1315 with follow-up). The 17-item CRA form included caries risk indicators, caries protective items, and clinical indicators. Conditional random forests classification trees were implemented to identify and assign variable importance to CRA items independently associated with baseline high-risk designation, baseline evident tooth decay, and follow-up evident decay. RESULTS: Thirteen individual CRA items, including all clinical indicators and all but one risk indicator, were independently and statistically significantly associated with student/resident providers' caries-risk designation. Provider-assigned baseline risk category was strongly associated with follow-up decay, which increased from low (20.4%), moderate (30.6%), to high/extreme risk patients (68.7%). Of baseline CRA items, before adjustment 12 were associated with baseline decay and 7 with decay at follow-up; however, in the conditional random forests models, only the clinical indicators (evident decay, dental plaque, and recent restoration placement) and one risk indicator (frequent snacking) were independently and statistically significantly associated with future disease, for which baseline evident decay was the strongest predictor. CONCLUSIONS: In this predominantly high-risk population under caries-preventive care, more individual CRA items were independently associated with providers' risk determination than with future caries status. These university dental providers considered many items in decision-making regarding patient risk, suggesting that in turn, these comprehensive CRA forms could also aid individualized care, linking risk assessment to disease management.

Caries inhibition with a CO2 9.3 µm laser: An in vitro study.

BACKGROUND AND OBJECTIVES: The caries preventive effects of different laser wavelengths have been studied in the laboratory as well as in pilot clinical trials. The objective of this in vitro study was to evaluate whether irradiation with a new 9.3 µm microsecond short-pulsed CO2 -laser could enhance enamel caries resistance with and without additional fluoride applications. STUDY DESIGN/MATERIALS AND METHODS: One hundred and one human tooth enamel samples were divided into seven groups. Each group was treated with different laser parameters (CO2 -laser, wavelength 9.3 µm, 43 Hz pulse-repetition rate, pulse duration between 3 µs at 1.5 mJ/pulse to 7 µs at 2.9 mJ/pulse). A laboratory pH-cycling model followed by cross-sectional microhardness testing determined the mean relative mineral loss delta Z (ΔZ) for each group to assess caries inhibition in tooth enamel by the CO2 9.3 µm short-pulsed laser irradiation. The pH-cycling was performed with or without additional fluoride. RESULTS: The non-laser control groups with additional fluoride had a relative mineral loss (ΔZ, vol% × µm) that ranged between 646 ± 215 and 773 ± 223 (mean ± SD). The laser irradiated and fluoride treated samples had a mean ΔZ ranging between 209 ± 133 and 403 ± 245 for an average 55% ± 9% reduction in mineral loss (ANOVA test, P < 0.0001). Increased mean mineral loss (ΔZ between 1166 ± 571 and 1339 ± 347) was found for the non-laser treated controls without additional fluoride. In contrast, the laser treated groups without additional fluoride showed a ΔZ between 470 ± 240 and 669 ± 209 (ANOVA test, P < 0.0001) representing an average 53% ± 11% reduction in mineral loss. Scanning electron microscopical assessment revealed that 3 µs pulses did not markedly change the enamel surface, while 7 µs pulses caused some enamel ablation. CONCLUSION: The CO2 9.3 µm short-pulsed laser energy renders enamel caries resistant with and without additional fluoride use. The observed enhanced acid resistance occurred with the laser irradiation parameters used without obvious melting of the enamel surface as well as after irradiation with energies causing cutting of the enamel. Lasers Surg. Med. 48:546-554, 2016. Published 2016. This article is a U.S. Government work and is in the public domain in the USA.

Approximal and occlusal carious lesions: Restorative treatment decisions by California dentists.

BACKGROUND: Investigators use questionnaire surveys to evaluate treatment philosophies in dental practices. The aim of this study was to evaluate the management strategies California dentists use for approximal and occlusal carious lesions. METHODS: In May 2013, the authors e-mailed a questionnaire that addressed approximal and occlusal carious lesion management (detection and restorative threshold, preferred preparation type, and restorative materials) to 16,960 dentists in California. The authors performed a χ(2) statistical analysis to investigate the relationship between management strategies and respondent demographic characteristics. RESULTS: The authors received responses from 1,922 (11.3%) dentists; 42.6% of the respondents would restore approximal lesions at the dentinoenamel junction, and 33.4% would wait until the lesion reached the outer one-third of dentin. The preferred preparation type was the traditional Class II preparation. Dentists who graduated more recently (20 years or less) were more likely to delay approximal restorations (P < .0001); 49.9% of the more recent graduates would wait to restore an occlusal lesion until the outer one-third of dentin was involved, and 42.6% would restore a lesion confined to enamel. CONCLUSIONS: There is wide variety among California dentists regarding their restorative treatment decisions, with most dentists restoring a tooth earlier than the literature would advise. More recent dental graduates were more likely to place their restorative threshold at deeper lesions for approximal carious lesions. PRACTICAL IMPLICATIONS: Clinical evidence shows that noncavitated carious lesions can be remineralized; therefore, early restorative treatment may no longer be necessary or appropriate. Noninvasive and minimally invasive measures should be taken into consideration.

Sustained effects of blue light on Streptococcus mutans in regrown biofilm.

In prior studies, exposure of Streptococcus mutans in biofilm to blue light using high fluences of up to 680 J/cm(2) did not interfere with bacterial capability to reform an initial biofilm; however, a delayed antibacterial effect was observed. Our aim was to determine the sustained effecttts of blue light-emitting diode (LED) curing light on the pathogenicity of the newly formed biofilm. S. mutans were grown to form biofilm that was exposed to blue light (wavelengths, 460-480 nm) for 1, 3, and 7 min (equivalent to 37, 112, and 262 J/cm(2), respectively). Then, bacteria were suspended and allowed to regrow into new biofilms. The regrown biofilms were assessed for bacterial quantification by optical density (OD) measurement and quantitative polymerase chain reaction (qPCR), bacterial viability and extracellular polysaccharide production by fluorescent staining using confocal scanning laser microscopy, acid production by bacteria (acidogenicity), and bacterial survival at low pH (aciduricity) using qPCR. Bacterial growth in the regrown biofilms was increased when samples were previously exposed to light; however, under the confocal microscopy, a higher proportion of dead bacteria and a reduction in polysaccharide production were observed. The acidogenicity from the regrown biofilm was lowered as fluences of light increased. The aciduricity of the regrown biofilm was decreased, meaning less growth of bacteria into biofilm in low pH with increasing fluences. Blue light has sustained effects on S. mutans bacteria grown into new biofilm. Although bacterial growth in biofilm increased, bacterial viability and virulence characteristics were impaired. The cariogenic potential over time of S. mutans previously exposed to blue light when grown on tooth surfaces is yet to be determined.