Risk assessment of dental caries by using Classification and Regression Trees

Risk Factors of Dental Caries in the Thai Population: The Retrospective Cohort Study

Aim

The aim of this retrospective cohort study was to determine the risk factors associated with the occurrence of dental caries increments in Thai dental patients.

Materials and Methods

The dental chart records of 500 patients who visited the Department of Advanced General Dentistry, Mahidol University during 2003-2013 were included in this research. Risk factors such as age, gender, medical history, marital status, routine oral checkup, oral appliance usage, initial and final records of decayed (DT)-missing-filled (DMF-T), dental history of tooth extraction due to caries, xerostomia, presence of visible plaque, presence of interproximal restoration, and caries risk level were retrieved from dental records. Cox proportional hazard regression model was used to determine the association of caries risk factors and new dental caries increments.

Results

The results indicated that the rate of incidence of new dental caries was 2.1 per 100 person-month. In the multivariate hazard model, past caries experience in more than three teeth (adjusted hazard ratio: 2.29, 95%CI: 1.53-3.44) and xerostomia (adjusted hazard ratio: 4.47, 95%CI: 1.82-10.98) were independent risk factors of dental caries increments. Other factors, such as demographic data, physical factors, clinical factors, and other contributing factors, were not associated with the incidence of new dental caries.

Conclusion

The presence of past caries experience and xerostomia were predictors of the occurrence of new dental caries.

Evidence-based Decisioning on the Management of a High Caries Risk Patient-A Case Report

Objective

The evidence-based approach to treatment planning has been at the forefront of clinical dentistry and the use of scientific evidence for clinical decisions has an impact on this case report, where the treatment planning of a high caries risk patient was performed with this approach.

Background

In this case report, management of a 30-year-old female patient with multiple carious lesions in her oral cavity has been discussed, and microbiological tests for caries risk assessment were performed that categorized her in the high caries risk group.

Methods

The management of this patient was formulated by carrying out a systematic search of the literature according to the clinical question. It is the evidence-based dentistry protocol, and the search was carried out in the following databases: PubMed, Embase, Medline, and Google Scholar. The CAMBRA protocol was employed for the management of high caries risk patients.

Results

A total of seven articles that included two randomized clinical trials, one case report, and four retrospective studies were identified for the evidence-based approach of the treatment planning.

Conclusion

The caries management by risk assessment has been advocated in this case report, where the patient was identified in the high caries risk group according to the caries assessment tests (microbiological), and the management was carried out inculcating the CAMBRA protocol.

Model for Predicting Temporomandibular Dysfunction: Use of Classification Tree Analysis

The aim of this study was to construct a predictive model that uses classification tree statistical analysis to predict the occurrence of temporomandibular disorder, by dividing the sample into groups of high and low risk for the development of the disease. The use of predictive statistical approaches that facilitate the process of recognizing and/or predicting the occurrence of temporomandibular disorder is of interest to the scientific community, for the purpose of providing patients with more adequate solutions in each case. This was a cross-sectional analytical population-based study that involved a sample of 776 individuals who had sought medical or dental attendance at the Family Health Units in Recife, PE, Brazil. The sample was submitted to anamnesis using the instrument Research Diagnostic Criteria for Temporomandibular Disorders. The data were inserted into the software Statistical Package for the Social Sciences 20.0 and analyzed by the Pearson Chi-square test for bivariate analysis, and by the classification tree method for the multivariate analysis. Temporomandibular disorder could be predicted by orofacial pain, age and depression. The high-risk group was composed of individuals with orofacial pain, those between the ages of 25 and 59 years and those who presented depression. The low risk group was composed of individuals without orofacial pain. The authors were able to conclude that the best predictor for temporomandibular disorder was orofacial pain, and that the predictive model proposed by the classification tree could be applied as a tool for simplifying decision making relative to the occurrence of temporomandibular disorder.

Inequality, Familial Aggregation, and Risk Prediction of Caries in Siblings

INTRODUCTION

Social and family conditions are likely of great importance to dental health; however, limited evidence of familial aggregation of caries among adolescent siblings exists. Moreover, social and family-level factors have never been evaluated as isolated caries predictors at the individual level.

OBJECTIVES

The objectives were to evaluate socioeconomic patterning of caries among siblings, assess sibling-specific aggregation of caries within families, and examine if such aggregation differed by parental socioeconomic position (SEP). We also evaluated the discriminant ability of sibling caries, SEP, and other social and familial factors in predicting caries in cosiblings.

METHODS

This nationwide register-based study included all 15-y-olds in Denmark in 2003 (index siblings) and their biological siblings born within ±3 y (cosiblings). Clinical and sociodemographic data for each subject were compiled from Danish national dental, social, and population registers. Caries was measured by the decayed, missing, and filled tooth surfaces (DMFS) index. Predictors included SEP (parental education, income, and occupational social class), gender, birth order, immigration status, and household type. Adjusted SEP-caries associations were estimated using negative binomial regression. Familial aggregation was evaluated using adjusted pairwise odds ratios from alternating logistic regressions. Caries prediction was based on classification and regression tree (CART) analyses.

RESULTS

The study included 23,847 sibling pairs (n = 47,694). Socioeconomic patterning of caries was similar among the index and cosiblings with significant graded SEP-caries associations. Significant sibling-specific aggregation of caries was observed; cosiblings of caries-affected index siblings had odds of having caries 3.9 times (95% confidence interval: 3.65-4.18) as high as that of cosiblings with caries-free index siblings. This sibling similarity was stronger in socioeconomically disadvantaged families (adjusted pairwise odds ratios: 3.08-5.47). CART revealed index sibling caries as the single most important caries predictor, with caries predicted in ≥84% of cosiblings of adolescents with ≥3 carious tooth surfaces.

CONCLUSIONS

Caries in a sibling should prompt preventive family-based approaches targeting cosiblings.

KNOWLEDGE TRANSFER STATEMENT

This study revealed significant socioeconomic patterning of caries in adolescent siblings. Prediction modeling indicated that the single most important caries predictor among cosiblings was index sibling caries. Information on sibling caries level should be routinely combined with clinical evaluation to identify children at risk. Moreover, information on social and family conditions should be used to target prevention and health promotion at the school or municipal level. These approaches could possibly contribute to reducing the existing caries inequalities.

Decision Tree Approach to the Impact of Parents' Oral Health on Dental Caries Experience in Children: A Cross-Sectional Study

Decision tree (DT) analysis was applied in this cross-sectional study to investigate caries experience in children by using clinical and microbiological data obtained from parent–child pairs. Thirty pairs of parents and children were recruited from periodontal and pediatric dental clinics. All participants were clinically examined for caries and periodontitis by a calibrated examiner. Cariogenic and periodontopathic bacteria examinations were conducted. The Kendall rank correlation coefficient was used to measure the association between data variables obtained through clinical and microbiological examinations. A classificatory inductive decision tree was generated using the C4.5 algorithm with the top-down approach. The C4.5 DT analysis was applied to classify major influential factors for children dental caries experience. The DT identified parents’ periodontal health classification, decayed, missing, filled permanent teeth (DMFT) index, periodontopathic test (PerioCheck) result, and periodontal pocket depth as the classification factors for children caries experience. 13.3% of children were identified with a low decayed, missing, filled primary teeth (dmft) index (dmft < 3) whose parents had a periodontal pocket depth ≤3.7, PerioCheck score >1, DMFT index <13.5, and periodontal classification >2. The DT model for this study sample had an accuracy of 93.33%. Here, parental periodontal status and parents’ DMFT were the factors forming the DT for children’s caries experience.

Identifying the critical factors that influence intraocular pressure using an automated regression tree

Background: Assessment of intraocular pressure (IOP) is an important test in glaucoma. In addition, anterior segment variables may be useful in screening for glaucoma risk. Studies have investigated the associations between IOP and anterior segment variables using traditional statistical methods. The classification and regression tree (CART) method provides another dimension to detect important variables in a relationship automatically.Aim: To identify the critical factors that influence IOP using a regression tree.Methods: A quantitative cross-sectional research design was used. Anterior segment variables were measured in 700 participants using the iVue100 optical coherence tomographer, Oculus Keratograph and Nidek US-500 ultrasonographer. A Goldmann applanation tonometer was used to measure IOP. Data from only the right eyes were analysed because of high levels of interocular symmetry. A regression tree model was generated with the CART method and Pearson’s correlation coefficients were used to assess the relationships between the ocular variables.Results: The mean IOP for the entire sample was 14.63 mmHg ± 2.40 mmHg. The CART method selected three anterior segment variables in the regression tree model. Central corneal thickness was the most important variable with a cut-off value of 527 µm. The other important variables included average paracentral corneal thickness and axial anterior chamber depth. Corneal thickness measurements increased towards the periphery and were significantly correlated with IOP (r ≥ 0.50, p ≤ 0.001).Conclusion: The CART method identified the anterior segment variables that influenced IOP. Understanding the relationship between IOP and anterior segment variables may help to clinically identify patients with ocular risk factors associated with elevated IOPs.

Multicenter study on caries risk assessment in adults using survival Classification and Regression Trees

Dental caries is an important public health problem worldwide. This study aims to prove how preventive therapies reduce the onset of caries in adult patients, and to identify patients with high or low risk of caries by using Classification and Regression Trees based survival analysis (survival CART). A clinical data set of 732 patients aged 20 to 64 years in nine Japanese general practices was analyzed with the following parameters: age, DMFT, number of mutans streptococci (SM) and Lactobacilli (LB), secretion rate and buffer capacity of saliva, and compliance with a preventive program. Results showed the incidence of primary carious lesion was affected by SM, LB and compliance with a preventive program; secondary carious lesion was affected by DMFT, SM and LB. Survival CART identified high-risk patients for primary carious lesion according to their poor compliance with a preventive program and SM (≥10⁶ CFU/ml) with a hazard ratio of 3.66 (p = 0.0002). In the case of secondary caries, patients with LB (≥10⁵ CFU/ml) and DMFT (>15) were identified as high risk with a hazard ratio of 3.50 (p < 0.0001). We conclude that preventive programs can be effective in limiting the incidence of primary carious lesion.

Using association rule mining to identify risk factors for early childhood caries

BACKGROUND AND OBJECTIVE

Early childhood caries (ECC) is a potentially severe disease affecting children all over the world. The available findings are mostly based on a logistic regression model, but data mining, in particular association rule mining, could be used to extract more information from the same data set.

METHODS

ECC data was collected in a cross-sectional analytical study of the 10% sample of preschool children in the South Bačka area (Vojvodina, Serbia). Association rules were extracted from the data by association rule mining. Risk factors were extracted from the highly ranked association rules.

RESULTS

Discovered dominant risk factors include male gender, frequent breastfeeding (with other risk factors), high birth order, language, and low body weight at birth. Low health awareness of parents was significantly associated to ECC only in male children.

CONCLUSIONS

The discovered risk factors are mostly confirmed by the literature, which corroborates the value of the methods.

Biopolymers from lactic acid bacteria. Novel applications in foods and beverages

Lactic acid bacteria (LAB) are microorganisms widely used in the fermented food industry worldwide. Certain LAB are able to produce exopolysaccharides (EPS) either attached to the cell wall (capsular EPS) or released to the extracellular environment (EPS). According to their composition, LAB may synthesize heteropolysaccharides or homopolysaccharides. A wide diversity of EPS are produced by LAB concerning their monomer composition, molecular mass, and structure. Although EPS-producing LAB strains have been traditionally applied in the manufacture of dairy products such as fermented milks and yogurts, their use in the elaboration of low-fat cheeses, diverse type of sourdough breads, and certain beverages are some of the novel applications of these polymers. This work aims to collect the most relevant issues of the former reviews concerning the monomer composition, structure, and yields and biosynthetic enzymes of EPS from LAB; to describe the recently characterized EPS and to present the application of both EPS-producing strains and their polymers in the fermented (specifically beverages and cereal-based) food industry.

Multicenter study on caries risk assessment in Japanese adult patients

OBJECTIVES

This study was conducted to identify significant risk factors for the onset and the accumulation of new caries in adult patients undergoing regular preventive therapy.

METHODS

The data of 732 patients from nine Japanese general dental practices were retrospectively analyzed. Classification and regression tree (CART) analysis was applied to develop a caries prediction model using the following patient parameters: age, number of teeth with caries experience (DMFT), levels of mutans streptococci (SM) and lactobacilli (LB), saliva flow rate and buffer capacity, and compliance with a preventive program. Poisson regression analysis was conducted to identify factors affecting caries accumulation within three years.

RESULTS

CART analysis identified patients at high risk for primary caries with an odds ratio of 3.08 (95%CI, 1.55-5.79; p=0.0018) according to SM levels and compliance; and those for secondary caries with an odds ratio of 3.69 (95%CI, 2.29-5.91; p<0.0001) according to LB and SM levels. Poisson regression analyses showed that accumulation of primary caries was affected by compliance (p<0.001), SM (p<0.001) and LB (p=0.013). Accumulation of secondary caries was affected by DMFT (p<0.001), SM (p<0.001) and LB (p<0.001).

CONCLUSIONS

CART is an important tool in identifying the risk of caries development in individual adult patients. Cariogenic bacteria are important factors for both the onset and accumulation of primary and secondary caries.

CLINICAL SIGNIFICANCE

Participation in a regular preventive program limits the onset and the accumulation of primary caries in adult patients.

Do hemophiliacs have a higher risk for dental caries than the general population?

OBJECTIVE

The aim of this study was to examine if patients with hemophilia were at increased risk for dental decay as compared to the general population.

MATERIALS AND METHODS

Census sampling was used in this case-control study to recruit cases (patients with hemophilia) and a control group individuals recruited randomly from the general population, which were matched with cases based on gender, age and place of residence. Clinical examinations included dental health and salivary assessments (flow rate, buffer capacity, caries-associated bacteria) and a structured questionnaire which inquired about socioeconomic status and dental health-related behaviors.

RESULTS

In the deciduous dentition, the overall caries experience (dmf) differed statistically significantly (P=0.003) between the hemophiliacs (2.6±2.6) and their matched healthy controls (6.1±2.5). Bivariate analyses did not reveal significant differences between cases and controls regarding salivary functions, except that higher bacteriological counts were found in healthy controls in deciduous dentitions than in patients with hemophilia (P=0.019). Children without hemophilia were from higher socioeconomic status families than hemophiliacs (P=0.004), but such differences were not found for adults (P=0.090). When compared to healthy adults, adult hemophiliacs had more gum bleeding at rest (P<0.001) as well as during their tooth brushing (P=0.007) and they also consumed more soft drinks than controls (P=0.025).

CONCLUSIONS

Better dental health was observed in children with hemophilia as compared to children without it. There were no differences in dental health between adult hemophiliacs and healthy controls from the general population. None of the linear multiple regression models confirmed hemophilia to be an additional caries risk when it was controlled for other caries determinants.

A retrospective analysis of caries treatment and development in relation to assessed caries risk in an adult population in Sweden

Background

The Public Dental Service of Västerbotten County (Sweden) recommends using population-based prevention strategies combined with an individual strategy for high-risk patients to manage caries. To facilitate this management strategy, all patients are evaluated for their risk of developing caries in the coming year using defined criteria. Using caries risk scoring over a seven-year period, the present study evaluates prophylactic measures, caries development, and non-operative treatments in adult patients.

Methods

From all adult patients (25–65 years; n = 76 320) scored with a high caries risk in 2005 (baseline) and with a dental visit in 2011, 200 subjects were randomly selected. In addition, an equally sized control group with a no/low caries risk was selected. Information concerning dental status, counselling, treatments, visits, and costs were retrieved from dental records.

Results

Over the seven-year study period, subjects with high caries risk had significantly higher caries incidence in spite of shorter recall intervals, more dental appointments, and higher costs for dental care than subjects with no/low caries risk. Non-operative measures, such as additional fluoride and individual counselling on diet at baseline (2005), was higher in the high caries risk group, whereas information about basic prophylaxis and counselling on oral hygiene showed only small differences. The frequency of non-operative measures given during the seven-year study period to patients in the high caries risk group is considered to be remarkably low and improvement, determined as reclassification from high to no/low caries risk from 2005 to 2011, was seen in only 13% of the participants.

Conclusions

This study formulated two major conclusions. First, adult patients with high or no/low caries represent different populations, that each contain distinct subpopulations, those who improve/impair or maintained their caries risk and disease progression. These groups need different strategies in disease treatment. Second, preventive measures and non-operative treatments were associated with improvements in caries risk and maintenance, but the extent to which such treatments were given to high caries risk subjects was unacceptably low. Improved adherence to the guidelines for caries treatment may reduce caries risk, visits to dental clinics, and costs for the patients.

Pattern recognition in long‐term Sooty Shearwater data: applying machine learning to create a harvest index

Rakiura Māori (New Zealand's southernmost group of indigenous peoples) have harvested the chicks of burrow-nesting Sooty Shearwaters (Tītī; Puffinus griseus) for generations. As part of the harvest process, some families have maintained annual harvest diaries, some dating back to the 1950s. We used generalized boosted regression models, a machine-learning algorithm, to calculate a harvest index that takes into account factors that could impact the numbers of birds taken on any given hunt. For predicted vs. observed values, r2 was between 0.59 and 0.90 for the nanao (first half of the season, when chicks are harvested from burrows during the day) and 0.67 and 0.88 for the rama (second half of the season, during which chicks are harvested from the surface at night). Exploration of the controlling factors of the models revealed that “day of season” plays an important role in predicting daily harvest during the second half of the season (the rama). The nightly tally in the rama peaked approximately halfway through (10–15 days in), which is probably related to the timing of birds emerging from burrows to fledge. The models also suggested that data from the rama (when chicks are 100–120 days old) may be the most suitable for long-term monitoring of populations of Sooty Shearwaters due to consistencies in calculated harvest indices between diaries. Nanao harvest indices, although less consistent, showed patterns similar to those of the rama. When comparing these data to the harvest indices calculated by general linear models by Clucas and colleagues, we found that the agreement between both indices was r2 = 0.31 and r2 = 0.59 for the nanao and rama, respectively. The use of machine learning to correct for extraneous factors (e.g., hunting effort, skill level, or weather) and to create standardized measures could be applied to other systems such as fisheries or terrestrial resource management.

Evaluation of polymerization characteristics and penetration into enamel caries lesions of experimental infiltrants

OBJECTIVES

To evaluate the properties of experimental infiltrant blends by comparing them with the commercial infiltrant Icon(®) and penetration homogeneity into enamel caries lesions.

METHODS

Groups were set up as follows: G1 (TEGDMA 100%); G2 (TEGDMA 80%, Ethanol 20%); G3 (TEGDMA 80%, HEMA 20%); G4 (TEGDMA 75%, BisEMA 25%); G5 (TEGDMA 60%, BisEMA 20%, Ethanol 20%); G6 (TEGDMA 60%, BisEMA 20%, HEMA 20%); G7 (TEGDMA 75%, UDMA 25%); G8 (TEGDMA 60%, UDMA 20%, Ethanol 20%); G9 (TEGDMA 60%, UDMA 20%, HEMA 20%) and Icon(®). Ten specimens were comprised by each group for the following tests (n=10): degree of conversion (DC), elastic modulus (EM), Knoop hardness (KH), and softening ratio (SR). Infiltrant penetration was evaluated using confocal microscopy (CLSM). Data were subjected to two-way ANOVA and a Tukey's test (5%). Data comparing experimental materials and Icon(®) were analysed using ANOVA and Dunnett's test (5%).

RESULTS

The highest DC values were found in G1, G7, G8, and G9. The lowest DC values were found in G2, G4, G5, and G6. EM and KHN were significantly lower in HEMA and with ethanol addition for all blends, except for G9. There was no significant difference among the groups regarding SR, and it was not possible to take KHN readings of G2, G5, and G8 after storage. There was no significant difference among groups for infiltrant penetration into enamel lesions.

CONCLUSIONS

The addition of hydrophobic monomers and solvents into TEGDMA blends affected DC, EM, and KHN. UDMA added to TEGDMA resulted in an increase in DC, EM, and KHN. Overall, solvents added to monomer blends resulted in decreased properties. The addition of hydrophobic monomers and solvents into TEGDMA blends does not improve the penetration depth of the infiltrants.

Patient stratification for preventive care in dentistry

Prevention reduces tooth loss, but little evidence supports biannual preventive care for all adults. We used risk-based approaches to test tooth loss association with 1 vs. 2 annual preventive visits in high-risk (HiR) and low-risk (LoR) patients. Insurance claims for 16 years for 5,117 adults were evaluated retrospectively for tooth extraction events. Patients were classified as HiR for progressive periodontitis if they had ≥ 1 of the risk factors (RFs) smoking, diabetes, interleukin-1 genotype; or as LoR if no RFs. LoR event rates were 13.8% and 16.4% for 2 or 1 annual preventive visits (absolute risk reduction, 2.6%; 95%CI, 0.5% to 5.8%; p = .092). HiR event rates were 16.9% and 22.1% for 2 and 1 preventive visits (absolute risk reduction, 5.2%; 95%CI, 1.8% to 8.4%; p = .002). Increasing RFs increased events (p < .001). Oral health care costs were not increased by any single RF, regardless of prevention frequency (p > .41), but multiple RFs increased costs vs. no (p < .001) or 1 RF (p = .001). For LoR individuals, the association between preventive dental visits and tooth loss was not significantly different whether the frequency was once or twice annually. A personalized medicine approach combining gene biomarkers with conventional risk factors to stratify populations may be useful in resource allocation for preventive dentistry (ClinicalTrials.gov, NCT01584479).

Effect of pit and fissure sealants on caries detection by a fluorescent camera system

OBJECTIVE

The aim of this study was to evaluate the effect of sealant placement on the detection of caries by a fluorescent camera (FC), the Spectra caries detector.

MATERIALS AND METHODS

In a laboratory study, FC images and readings were obtained from 31 extracted teeth, before and following application of clear sealants (Shofu Clear or Delton unfilled), or opaque sealants (3M Clinpro or Delton FS). Teeth were then sectioned and examined for enamel or dentine caries. Using each tooth's true caries diagnosis, the sensitivity and specificity of the FC measurements in detecting dentine caries was calculated. In the clinical study, FC readings were obtained from 41 molars in children prior to and following application of clear sealants.

RESULTS

Following application of Shofu or Delton unfilled there were reductions in the mean FC readings of 10% (p=0.5) and 8.2% (p=0.009), respectively. Application of two opaque sealants, 3M or Delton FS significantly reduced mean FC readings 16.2% and 20.8% (p<0.5), respectively. Although the carious lesions could still be observed in FC images from teeth with opaque sealants there was a significant loss of sensitivity in detecting dentinal caries. Clear sealant application caused an insignificant loss of detection sensitivity. Following application of clear sealants to children's molars there was a small (4.01%) but significant (p<0.01) reduction in FC readings recorded from these teeth.

CONCLUSIONS

The FC can detect caries under clear sealants with little loss of sensitivity. Although lesions can be seen through opaque sealants, loss of sensitivity precludes accurate lesion assessment.

Digital image analysis method to assess the performance of conventional and self-limiting concepts in dentine caries removal

OBJECTIVE

To assess dentine caries removal effectiveness (CRE) and minimal invasiveness potential (MIP) of carbide and polymer burs.

METHODS

Sectioned carious molars were photographed. Digital images were taken, before and after caries removal, using a Digital Single Lens Reflex camera. The following regions of interest were measured using visual criteria: Residual Infected Dentine (RI), Residual Affected Dentine (RA), Removal Sound Dentine (RA), Prepared Cavity (PC) and Removed Sound Dentine (RS). CRE was determined on basis of: relative residual infected dentine (RI/II), relative residual carious-affected dentine (RA/IA) and total relative residual dentine (RI+RA/II-IA). MIP was determined on basis of: infected dentine cavity size (PC/II), total relative cavity size (PC/II+IA), and corrected relative cavity size (PC-RS/II+IA).

RESULTS

The polymer bur showed the highest preservation of carious-affected dentine after excavation, when the RA/IA ratio was studied. Both kind of burs showed similar values after assessing the RI/II and RI+RA/II-IA ratios. The infected dentine relative cavity size (PC/II) was higher when the carbide bur was used. Both burs attained similar PC/II+IA and PC-RS/II+IA ratios.

CONCLUSIONS

Polymer burs accomplished the concept of minimal-invasive dentistry, showing its self-limiting ability. The minimal-invasiveness potential showed that carbide burs resulted in the worst compromise between effective and selective infected-caries removal.

How regular visits and preventive programs affect onset of adult caries

If it is to be effective, preventive dental treatment must be based on an individual's risk of caries and periodontal disease. However, hitherto, preventive treatment has been generally conducted without proper caries-risk assessment because of lack of knowledge about an individual's caries risk. This study sought to identify high-risk adult patients and examine the effectiveness of preventive programs. Data for 442 patients from a single general practice who met the inclusion criteria were analyzed. Multiple logistic-regression analysis showed that high levels of mutans streptococci (SM) correlated with the onset of primary and secondary caries, with odds ratios of 2.34 (95%CI: 1.15-4.76, p = 0.019) and 2.22 (95%CI: 1.06-4.62, p = 0.034), respectively. Lactobacilli (LB) also correlated with secondary caries, with an odds ratio of 3.34 (95%CI: 1.35-6.85, p = 0.007). When the patients were checked after three years of a preventive program, the correlation with SM and LB disappeared. Survival analyses by Cox regression models and Kaplan-Meier methods showed that secondary caries was difficult to control by conventional preventive programs alone in patients with high levels of cariogenic bacteria. In conclusion, cariogenic bacteria play an important role in the incidence of caries, and additional intensive preventive treatment should be considered for high-risk patients.

Differences between reported and actual restored caries lesion depths: results from The Dental PBRN

OBJECTIVE

The objectives of this research were to (1) quantify the discordance between the caries lesion depth at which dentists restored initial lesions during a clinical study ("actual depth") and the lesion depth that they reported during a hypothetical clinical scenario ("reported depth"); (2) test the hypothesis that certain practitioner, practice, patient, and caries lesion characteristics are significantly associated with this discordance.

METHODS

Practitioner-investigators who perform restorative dentistry in their practices completed an enrollment questionnaire and participated in two consecutive studies on caries diagnosis and treatment. The first study was a survey asking about caries treatment. The second study collected data on restorations placed in routine clinical practice due to caries in patients over 19 years of age on occlusal surfaces only or proximal surfaces only. We report results on 2691 restorations placed by 205 dentists in 1930 patients with complete data.

RESULTS

Discordance between actual depth and reported depth occurred in only about 2% of the restorations done due to proximal caries, but about 49% of the restorations done due to occlusal caries. Practice type, restorative material used and the diagnostic methods used were significantly associated with discordance.

CONCLUSION

Dentists frequently restored occlusal caries at a shallower depth as compared to their reported depth, but the discordance was very small for proximal lesions. Discordance for occlusal caries was more common when radiographs were not taken or if a resin restoration was placed.

Genetic variation in MMP20 contributes to higher caries experience

Matrix metalloproteinases play an important role during the initial process of enamel development and therefore may play a role in caries.

OBJECTIVES

To evaluate the association between MMP20 and caries experience in Brazilian children.

METHODS

Eligible unrelated children with or without caries were evaluated using a cohort design. Demographic data and oral health habits were obtained though a questionnaire. Caries data was collected by clinical examination. Genotyping of the selected polymorphism was carried out by real-time PCR from genomic DNA. Allele and genotype frequencies were compared between groups with distinct caries experience and oral health habits.

RESULTS

Of 388 subjects, 161 were caries free children. There were no differences between caries levels and genotype distribution in the total cohort. When ethnic background was considered, differences in genotype distribution were observed in caries free children vs. children with caries in Caucasians (p=0.03). Differences could also be seen when poor oral hygiene was used to stratify the analysis (p=0.02). Regression analysis, adjusted for genotype and ethnicity, confirmed that ingestion of sweets between meals increases the risk of presenting carious lesions (p=0.00001; OR=2.33; 95%CI 1.53-3.54).

CONCLUSION

Variation in MMP20 may be associated with caries experience mainly in Caucasian subjects with poor oral health habits.

Intraoral pH measurement of carious lesions with qPCR of cariogenic bacteria to differentiate caries activity

OBJECTIVES

A low pH environment is created by cariogenic bacteria. This study was aimed to measure pH of carious lesions intraorally using a micro-pH sensor, and assess predominant acid-producing cariogens by qPCR to differentiate caries activities.

METHODS

103 dentine lesions classified as active or arrested caries based on the clinical and radiological examinations were collected from patients after intraoral measurement of the lesion surface pH using a micro-pH sensor. Quantitative detection of genomic DNA copies of target cariogenic bacteria (mutans streptococci and Lactobacillus spp.) in each lesion was performed using real-time PCR. Correlation between the pH ranges and the number of bacterial species was examined by Spearman test.

RESULTS

50 samples were diagnosed as active and 53 as arrested lesions. Statistically significant difference was observed on average surface pH value between active and arrested lesions (p<0.05). Prevalence of Lactobacillus spp. was higher in active lesions than in arrested lesions (76% vs. 58% of samples, respectively). When the carious lesions were categorised into four different pH ranges (up to 5.5, from 5.6 to 5.8, from 5.9 to 6.1 and 6.2 or above), increased prevalence of Lactobacillus spp. was observed with decrease of pH levels. A significant negative relationship was found between pH value and number of Lactobacillus spp. (r=-0.209, p<0.05) but no such correlation was found for mutans streptococci.

CONCLUSIONS

Intraoral pH measurement might be clinically useful to determine acidity of the local environment of carious lesions as one aspect of the caries activity assessment.

CLINICAL SIGNIFICANCE

The population of certain bacteria may indicate activity of carious lesions. Intraoral pH measurement of the carious lesions using a micro-pH sensor may be a clinically feasible method for assessment of lesion acidity.