Multiple imputation of dental caries data using a zero-inflated Poisson regression model

Excess zeros exhibited by dental caries data require special attention when multiple imputation is applied to such data. Objective: The objective of this study was to demonstrate a simple technique using a zero‐inflated Poisson (ZIP) regression model, to perform multiple imputation for missing caries data. Methods: The technique is demonstrated using data (n = 24,403) from a medical office‐based preventive dental program in North Carolina, where 27.2 percent of children (n = 6,637) were missing information on physician‐identified count of carious teeth. We first estimate a ZIP regression model using the nonmissing caries data (n = 17,766). The coefficients from the ZIP model are then used to predict the missing caries data. Results: This technique results in imputed caries counts that are similar to the nonmissing caries data in their distribution, especially with respect to the excess zeros in the nonmissing caries data. Conclusion: This technique can be easily applied to impute missing dental caries data.     

Obesity,dietary sugar and dental caries in Australian adults

Objectives: To determine the association of overweight/obesity, dental caries and dietary sugars in Australian adults. Materials and methods: The National Survey of Adult Oral Health (NSAOH) 2004–2006 provided data for analysis of dental caries experience. Self-reported body weight and height were used to calculate body mass index (BMI) for a subsample (n = 3,745, 89.8%) of the NSAOH data. A self-report questionnaire of 13 food items estimated the daily intake of added sugar, total sugars and total carbohydrate, using food composition estimates from the AUSNUT2011–2013. Bivariate analyses (Pearson’s Chi-square with Rao–Scott adjustment and Student’s t-tests) were used to determine the association of overweight/obesity, dental caries, sugar variables and putative confounders. Poisson regression models for the Decayed, Missing and Filled Teeth Index and individual measures of decayed, missing and filled teeth were constructed, with models containing BMI, dietary added sugar, total sugar and total carbohydrate, controlling for putative confounders. Results: There was a positive association between dental caries experience and being overweight or obese compared with having normal weight or being underweight as well as between sugar consumption with all four dental caries outcome measures. When controlled for putative confounders where sugar consumption was identified as a key determinant, the statistical significance between dental caries experience and being overweight or obese disappeared. The demographic and socioeconomic factors associated with dental caries experience were age, sex, education, smoking status and usual reason for dental visit. Conclusion: Analysis of the relationship between dental caries and obesity must include data about sugar and carbohydrate consumption.     

Dental caries in HIV-seropositive women

Reports that compare dental caries indices in HIV-seropositive (HIV+) subjects with HIV-seronegative (HIV-) subjects are rare. The objective of this study was to determine if there was an association between HIV infection and dental caries among women enrolled in the Women's Interagency HIV Study. Subjects included 538 HIV+ and 141 HIV- women at baseline and 242 HIV+ and 66 HIV- women at year 5. Caries indices included DMFS and DFS (coronal caries) and DFSrc (root caries). Cross-sectional analysis of coronal caries data revealed a 1.2-fold-higher caries prevalence among HIV+ women compared with HIV- women. Longitudinally, DMFS increased with increasing age and lower average stimulated salivary volume. Root caries results were not significant except for an overall increased DFSrc associated with smoking. Anti-retroviral therapy was not identified as a risk factor for dental caries.     

An ecological study on the association of public dental health activities and sociodemographic characteristics with caries prevalence in Japanese 3-year-old children

The aim of this ecological study was to determine the association of the frequency of dental health activities conducted as public health service and sociodemographic characteristics with caries prevalence in Japanese 3-year-old children using data for each municipality as one unit. Data on caries prevalence in 3-year-old children in 2000 were obtained from 3,251 municipalities (almost all municipalities in Japan). Caries prevalence for each municipality was recalculated using the empirical Bayes estimation model to make adjustments for variations in municipalities with small numbers of children. Explanatory factors included annual frequency of dental health activities such as dental health education and topical fluoride application programs and various sociodemographic characteristics. Multiple linear regression analysis was applied to examine the associations between caries prevalence and annual frequency of dental health activities with adjustment of other sociodemographic variables. Variations in caries prevalence in municipalities with small populations became smaller after being adjusted by the empirical Bayes estimation model. Multiple linear regression analysis showed significant associations of caries prevalence with sociodemographic characteristics such as the proportion of residents with university degrees, total fertility rate, and the proportion of workers in the manufacturing industry (p < 0.001). Annual frequency of topical fluoride application showed a significant but relatively weak association with caries prevalence (p < 0.001), explaining only 0.8% of the total variation in caries prevalence, whereas no correlation was found between caries prevalence and annual frequency of dental health education. It was concluded that the effect of the fluoride application service on caries prevalence in 3-year-old children, although statistically significant, was of far lower clinical significance than sociodemographic characteristics.     

Food insecurity and dental caries in schoolchildren: a cross‐sectional survey in the western Brazilian Amazon

We analyzed the association between food insecurity and dental caries in 7‐ to 9‐yr‐old schoolchildren. We performed a cross‐sectional survey nested in a population‐based cohort study of 203 schoolchildren. The participants lived in the urban area of a small town within the western Brazilian Amazon. Dental examinations were performed according to criteria recommended by the World Health Organization. The number of decayed deciduous and permanent teeth as a count variable was the outcome measure. Socio–economic status, food security, behavioral variables, and child nutritional status, measured by Z‐score for body mass index (BMI), were investigated, and robust Poisson regression models were used. The results showed a mean (SD) of 3.63 (3.26) teeth affected by untreated caries. Approximately 80% of schoolchildren had at least one untreated decayed tooth, and nearly 60% lived in food‐insecure households. Sex, household wealth index, mother's education level, and food‐insecurity scores were associated with dental caries in the crude analysis. Dental caries was 1.5 times more likely to be associated with high food‐insecurity scores after adjusting for socio–economic status and sex. A significant dose–response relationship was observed. In conclusion, food insecurity is highly associated with dental caries in 7‐ to 9‐yr‐old children and may be seen as a risk factor. These findings suggest that food‐security policies could reduce dental caries.     

Inequalities in the distribution of dental caries among 12-year-old Brazilian schoolchildren

We assessed the inequality in the distribution of dental caries and the association between indicators of socioeconomic status and caries experience in a representative sample of schoolchildren. This study followed a cross-sectional design, with a sample of 792 schoolchildren aged 12 years, representative of this age group in Santa Maria, RS, Brazil. Guardians answered questions on socioeconomic status and a dental examination provided information on the dental caries experience (DMF-T). Inequality in dental caries distribution was measured by the Gini coefficient and the Significant Caries Index (SiC). The assessment of association used Poisson regression models. Socioeconomic factors were associated with prevalence of dental caries for the whole sample and also for individuals with a high-caries level. Children from low-income households had the highest prevalence of dental caries. The Gini coefficient was 0.7 and the SiC Index 2.5. The percentage of caries prevalence was 39.3% (95% CI: 35.8%-42.8%) and the mean for DMF-T was 0.9 (± SD 1.5). Inequalities in the distribution of dental caries were observed and socioeconomic factors were found to be strong predictors of the prevalence of oral disease in children of this age group.     

A time-series analysis of caries status among adolescents in relation to socioeconomic variables in Göteborg, Sweden

The aim of this study was to detect, using time-series analysis methods, whether measurable socioeconomic adjustments for the time period 1986-96, as presented by caries index values, could be related to a new trend in caries status development for specific age groups leaving the free state-organized dental care system. In the study, G?teborg was divided into four districts. The study showed a favorable development in dental health for the 15-19 age group. However, the caries incidence index DSa (decayed approximal surfaces) values showed no or only negligible signs of lower mean values. During the study period, the study showed an unfavorable trend concerning the socioeconomic variables related to health care. However, the incongruity for the different districts between the trend results of the caries index values and the contemporaneous socioeconomic variable development indicated few signs of relationship. In relation to general discussions of environmental questions, the idea of sustainable development was discussed when applied to the field of dental care. The results of this study indicate that dental health, in times of major economic adjustments and lack of resources for health care for the 15-19 age group in G?teborg--as interpreted by the caries indices used is an example of sustainable dental health development.     

Salivary lactobacillus counts in the prediction of caries activity

Abstract The aim of the study was lo investigate the reliability and clinical value for prediction of caries activity of determining the number of lactobacilli in saliva, the salivary secretion rate and the presence of yeasts in the saliva. For this purpose one entire age group of pupils (115 14-year-olds) attending one of the compulsory 9-year comprehensive schools in Örebro was selected for longitudinal examination. Over a period of 64 weeks three clinical recordings were made and seven salivary samples were collected. The correlations between caries activity, caries frequency (DFS), lactobacillus counts, yeasts in saliva, salivary secretion rate and gingivitis were examined. The results showed that in spite of a well-organized dental health service, including adequate preventive measures, a pronounced variation in caries activity remained and thus a means of predicting the onset of caries would be a valuable asset. Statistically significant correlations were found between caries activity on the one hand and caries frequency and lactobacillus counts on the other. The lactobacillus count was found to be a suitable measure in predicting caries activity. It was concluded that the lactobacillus count should be used for caries prediction in healthy, properly treated patients. It is important that there are no areas of microbial retention on the teeth such as open carious lesions, poorly executed restorations, dentures or orthodontic bands. In such situations, the lactobacillus count seems to relied the frequency of ingested fermentable carbohydrates and thus, indirectly, the risk of initiating carious lesions.     

Etiologic models for incident periodontal attachment loss in older adults

Etiologic factors for incident periodontal attachment loss (ALOSS) have not been conclusively identified. The purpose of this study was to develop etiologic models for ALOSS in older adults. Data on 697 older blacks and whites were obtained from 5 sequential examinations over 7 years in the Piedmont 65+ dental study, a complex random sample of older adults in North Carolina. Multivariable Poisson regression models were fit for average number of ALOSS events per person or site month at risk. In models for whites, molar sites, sites with adjacent caries, sites in persons who had: Porphyromonas gingivalis (P.g.) at least 2% of total microbial count (TMC), never had a dental checkup, more depression symptoms, fewer than 12 years of education, higher BANA score, or smoked, had significantly higher rates of ALOSS. In a separate model for blacks, interproximal and molar sites, sites in blacks who had: P.g. at least 2% of TMC, higher BANA score, never had a dental checkup, lower socioeconomic status (SES), or smoked, had significantly higher rates of ALOSS. These results confirm a multifactorial etiology for ALOSS in older adults and indicate that interventions aimed at infection, smoking, and preventive dental care utilization, may be most useful.     

Dental Caries and Fluorosis Prevalence and Their Relationship with Socioeconomic and Behavioural Variables Among 12-year-old Schoolchildren

Purpose: To evaluate caries experience and fluorosis prevalence in 12-year-old schoolchildren in Piracicaba, Brazil in 2007 and to verify the relationship of these changes with socioeconomic and behavioural variables. Materials and Methods: The sample consisted of 724 schoolchildren from public and private schools. A calibrated dentist performed the examination under natural light using CPI probes and mirrors. The mean number of decayed, missing and filled permanent teeth (DMFT) and the SiC (Significant Caries Index) were determined for dental caries and the Thylstrup and Fejerskov index (T-F) for fluorosis. Socioeconomic and behavioural variables were collected by means of a questionnaire. Multiple logistic regression analyses were performed to verify the relationship of caries and fluorosis with socioeconomic and behavioural variables. Results: The DMFT and SiC indices were 0.85 (±1.54) and 2.52 (±1.72). Fluorosis prevalence was 29.42%. The regression models showed that children whose families earned up to four minimum wages were 2.58 times more prone to having caries than those whose families earned over four minimum wages. Furthermore, children who visited the dentist were 4.27 times more likely to have DMFT > 0. However, for fluorosis, the regression model was not significant. Conclusions: The 12-year-old schoolchildren in Piracicaba presented very low caries prevalence. Significant associations were observed between the presence of caries, monthly family income and visiting the dentist. Considering dental fluorosis, the majority of the sample presented no clinical signs of fluorosis.     

Prevalence of dental caries and caries-related risk factors in premature and term children

This study evaluated the prevalence of enamel defects and dental caries and their risk factors on primary and permanent dentitions of prematurely-born children and term children. Eighty children were examined, 40 born prematurely (G1) and 40 born term (G2), in the age group between 5 and 10 years. The demographic variables, medical history and oral health behaviors were recorded on a questionnaire. The teeth were examined for presence of deficiencies of the enamel and caries that were registered. The caries were registered, focusing on the indices dmft (decayed, missing, and filled primary teeth) and DMFT (decayed, missing, and filled permanent teeth). The results showed that 75% of the total sample had enamel defects. The logistic regression model showed that other risk factors such as per capita family income, educational level, dietary and hygiene habits, fluoride exposure, trauma, and diseases had no correlation with enamel defects and caries. A smaller value of total DMFT (0.95) was found in the group of premature children in comparison to the term children (2.07) p = 0.0164. There was no difference concerning the permanent dentition between the two groups (p = 0.9926). One concludes that prematurity can't be a predisposing factor for the presence of dental caries.     

Statistical methods for comparing dental diagnostic procedures

In dental diagnosis, there are typically two or more clinical diagnostic procedures which may be used either independently or jointly to reach a conclusion regarding the presence of a particular disease in a patient. To determine which of these diagnostic procedures are more accurate, statistical methods may be applied to research data in which the true health status as well as the diagnosis provided by each clinical procedure are available on each observation. Results arising from this type of analysis can be of great interest to clinicians when the diagnostic procedures themselves are costly, painful, or even potentially harmful to the patient. Considered here is the special situation encountered in dental research in which each patient can have multiple concurrent cases of a certain disease such as caries, for then the statistical evaluation of diagnostic procedures is even further complicated. This report describes several statistical approaches for comparing the efficacy of diagnostic tests and illustrates their application on data from a study of diagnostic radiographs for dental caries.     

Disparities in Early Childhood Caries

Despite remarkable reduction in the prevalence of dental caries in the United States, dental caries is still a highly prevalent disease among children who are socially disadvantaged (racial/ethnic minority, poor, rural, immigrants). Consequently, caries sequelae such as dental pain, need for dental treatment under general anesthesia, and future orthodontic treatment, are also concentrated among the most socially disadvantaged children. To make the situation more appalling, those children who need treatment the most are the ones least likely to visit the dentist. Low income children are less likely to visit the dentist in part because of family's competing needs for limited resources, shortage of pediatric dentists, and dentists not taking uninsured or publicly insured patients. In the same vein, if these children do not have access to dental care, they are deprived from effective caries preventive measures that are dentist-dependent such as sealants and professionally applied fluoride. Dentistry has done well at devising caries preventive and treatment strategies; but these strategies have missed the most needed segment of society: disadvantaged children. The challenge now is to develop innovative strategies to reach these children.     

Metabolic control as a modifier of the association between salivary factors and dental caries among diabetic patients

The aim here was to analyze the role of metabolic control as a modifier of the association of salivary factors with dental caries among diabetic patients. Cross-sectional data were gathered from 149 insulin-dependent diabetes mellitus patients by means of clinical examination, a quantitative questionnaire and patient records. Dental caries was measured as the number of decayed surfaces. The data were analyzed using negative binomial regression models. HbA1(c) level appeared not to be associated with dental caries. Of the salivary factors, only high levels of mutans streptococci (MS) and lactobacilli were associated with dental caries. Among the subjects with HbA1(c) > or =8.5, the presence of dental caries was more distinctly associated with higher levels of MS (RR = 3.86, CI: 1.39-11.96) and lactobacilli (RR = 3.59, CI: 1.44-9.33) compared to those with HbA1(c)<8.5. It can be concluded that poor glycemic control strengthens the positive association of MS and lactobacilli with dental caries.     

Effect of different frequencies of preventive maintenance treatment on dental caries: five-year observations in general dentistry patients

A long-term study in adults at a public dental clinic in Sweden was initiated to evaluate the relative effectiveness of prophylactic treatments on the progression of dental caries and periodontal disease. With treatments scheduled every 3rd, 6th, 12th or 18th month, this report presents results on caries for the 3-month, 6-month and 18-month groups, and evaluates the impact of various caries-related risk factors. Caries increment over approximately 5 years was determined by adding clinical and radiographic findings of manifest primary and secondary caries during the study. Overall caries activity among all 105 participating individuals was low to moderate. No significant differences for caries on any of the various tooth surfaces or for total caries were observed among the three groups. Multiple regression analysis with 5-year caries increment as dependent variable showed that the following factors had a statistically significant association with caries increment: percentage filled surfaces at baseline examination, dietary score, plaque score, and number of mutans streptococci and lactobacilli in saliva. Non-significant factors included number of preventive treatments provided during the 5-year interval. The results of this long-term trial suggest that preventive treatments as often as every 3-6 months may not be justified in the case of patients with low to moderate caries activity.     

Effect of different frequencies of preventive maintenance treatment on dental caries: five-year observations in general dentistry patients

A long-term study in adults at a public dental clinic in Sweden was initiated to evaluate the relative effectiveness of prophylactic treatments on the progression of dental caries and periodontal discase. With treatments scheduled every 3rd, 6th, 12th or 18th month, this report presents results on caries for the 3-month, 6-month and 18-month groups, and evaluates the impact of various caries-related risk factors. Caries increment over approximately 5 years was determined by adding clinical and radiographic findings of manifest primary and secondary caries during the study. Overall caries activity among all 105 participating individuals was low to moderate. No significant differences for caries on any of the various tooth surfaces or for total caries were observed among the three groups. Multiple regression analysis with 5-year caries increment as dependent variable showed that the following factors had a statistically significant association with caries increment: percentage filled surfaces at baseline examination, dietary score, plaque score, and number of mutans streptococci and lactobacilli in saliva. Non-significant factors included number of preventive treatments provided during the 5-year interval. The results of this long-term trial suggest that preventive treatments as often as every 3 6 months may not be justified in the case of patients with low to moderate caries activity.     

The prescription and outcomes of fissure sealants applied to a group of high caries risk children by general dental practitioners working in the North West of England

OBJECTIVE: To describe the use and outcomes of fissure sealants applied to the first permanent molars (FPMs) of children with high caries risk. DESIGN: Retrospective cohort study. SETTING: General dental practices in North West England. PARTICIPANTS: 677 children between the ages of 5 and 14 years who had dmfs > or =2, and regularly attended 50 general dental practitioners. OUTCOMES: Analyses were performed at patient level. Logistic regression models, taking into account the clustering of subjects within dental practices, were fitted to identify whether the decision to fissure seal FPMs was significantly associated with gender, socio-economic status, number of carious primary teeth and percentage of carious primary teeth filled. Similar logistic regression models were fitted for caries experience in FPMs. RESULTS: Poorer children were significantly (p < 0.05, OR = 0.84, 95% CI = 0.71, 0.99) less likely to receive fissure sealants than affluent children, whilst girls (p < 0.01, OR = 1.54, 95% CI = 1.12, 2.12) were more likely to have sealants than boys. The total number of carious primary teeth was also a significant (p < 0.01, OR = 1.15, 95% CI = 1.06, 1.25) independent predictor of dentists' decisions to fissure seal FPMs. For each carious primary tooth, the odds of having caries in FPMs increased by 1.16 (95% CI = 1.06, 1.26). Analysis showed that pit and fissure caries in FPMs was not affected by the presence or absence of fissure sealants. CONCLUSIONS: The decision to fissure seal FPMs is affected by caries experience in the primary dentition. Girls and affluent children were more likely to receive fissure sealants. It appears that the placement of fissure sealants by general dental practitioners was not effective in preventing pit and fissure caries in these high-risk children.     

Assessment of periodontal diseases in epidemiological investigations: a critical review

Like dental caries, epidemiological assessment of periodontal disease is important for purposes of recognizing the extent of the disease in the population as well as a basis for planning and evaluating preventive and treatment programmes. while present day measurement methods for dental caries are excellent such is not true for periodontal diseases. This paper reviews the development and usefulness of different indices for the assessment of periodontal disease and treatment needs in epidemiological investigations.