Interexaminer agreement in the measurement of periodontal disease

Sample size determination for conducting a pilot study to assess reliability of a questionnaire

This article is a narrative review that discusses the recommended sample size requirements to design a pilot study to assess the reliability of a questionnaire. A list of various sample size tables that are based on the kappa agreement test, intra-class correlation test and Cronbach's alpha test has been compiled together. For all calculations, type I error (alpha) was set at a maximum value of 0.05, and power was set at a minimum value of 80.0%. For the kappa agreement test, intra-class correlation test, and Cronbach's alpha test, the recommended minimum sample size requirement based on the ideal effect sizes shall be at least 15, 22, and 24 subjects respectively. By making allowances for a non-response rate of 20.0%, a minimum sample size of 30 respondents will be sufficient to assess the reliability of the questionnaire. The clear guideline of minimum sample size requirement for the pilot study to assess the reliability of a questionnaire is discussed and this will ease researchers in preparation for the pilot study. This study provides justification for a minimum requirement of a sample size of 30 respondents specifically to test the reliability of a questionnaire.

Edentulism is associated with increased risk of all-cause mortality in adult men

BACKGROUND

Prior reports of positive associations between edentulism and all-cause mortality have been limited by onetime assessments of edentulism and inadequate control of known confounding variables. The authors aimed to assess the association between edentulism and mortality using a longitudinal clinical oral health cohort.

METHODS

The authors used data from the Department of Veterans Affairs Dental Longitudinal Study, an ongoing, closed-panel cohort study from 1968 through 2019 (N = 1,229). Dentition status was evaluated through triennial clinical examinations. Mortality was assessed via the National Death Registry. The authors used Cox regression models to estimate the association between edentulism and all-cause mortality after covariate adjustment. Furthermore, the authors calculated propensity scores and assessed hazard ratios (HRs) in a trimmed, matched, and inverse probability weighted sample.

RESULTS

Participants who were edentulous (N = 112) had 1.24 (95% CI, 1.00 to 1.55) times the hazard of all-cause mortality compared with those who were nonedentulous, after adjustment with time-varying covariates. Use of propensity scores in the model resulted in slightly elevated HRs compared with the standard Cox model, regardless of propensity score method; adjusted HRs were 1.35 (95% CI, 1.01 to 1.80) after matching, 1.26 (95% CI, 1.00 to 1.59) after trimming, and 1.29 (95% CI, 1.18 to 1.42) after inverse probability weighting.

CONCLUSIONS

Edentulism was associated with an increased risk of all-cause mortality in a cohort that captured incident edentulism. This association was consistent after multiple methods to account for confounding.

PRACTICAL IMPLICATIONS

The findings of this study suggest that edentulism is associated with an increase in risk of mortality, after accounting for salient confounding variables using multiple approaches. Efforts to improve equitable access to tooth-preserving treatments are critical.

Biocultural pathways linking periodontal disease expression to food insecurity, immune dysregulation, and nutrition

OBJECTIVES

In this article, we test theoretical pathways leading to and resulting from periodontal disease to better understand how periodontal disease, which is measurable in both past and present populations, integrates biocultural context and affects whole-body physiology.

METHODS

We use data from the National Health and Nutrition Examination Survey (NHANES) 2003-2004 and logistic and linear regressions to test pathways linking psychosocial stress to periodontal disease, and periodontal disease to serum vitamin C levels. We then use causal mediation analysis to test the role of mediating variables in these pathways (n = 1853 individuals).

RESULTS

Food insecurity was positively associated with periodontal disease and negatively associated with serum counts of C-reactive protein (CRP) and neutrophils. Neither CRP nor neutrophils significantly mediated the relationship between food insecurity and periodontal disease. Periodontal disease was negatively associated with serum vitamin C levels and positively associated with neutrophil counts. Neutrophils may mediate the relationship between periodontal disease and vitamin C.

CONCLUSIONS

We identify two main findings: (a) periodontal disease contributes to and may result from immune dysregulation, particularly of neutrophils, and (b) an immune response to chronic infection such as periodontal disease is metabolically expensive for the body to maintain and likely depletes serum micronutrient levels. Both micronutrient status and serum neutrophil counts affect multiple skeletal and physiological phenotypes and thus position periodontal disease in whole-body context.

A quantitative bias analysis to assess the impact of unmeasured confounding on associations between diabetes and periodontitis

AIM

To investigate unmeasured confounding in bidirectional associations between periodontitis and diabetes using quantitative bias analysis.

METHODS

Subsamples from the Veterans Affairs Dental Longitudinal Study were selected. Adjusted for known confounders, we used Cox proportional hazards models to estimate associations between pre-existing clinical periodontitis and incident Type II Diabetes (n = 672), and between pre-existing diabetes and incident severe periodontitis (n = 521), respectively. Hypothetical confounders were simulated into the dataset using Bernoulli trials based on pre-specified distributions of confounders within categories of each exposure and outcome. We calculated corrected hazard ratios (HR) over 10,000 bootstrapped samples.

RESULTS

In models using periodontitis as the exposure and incident diabetes as the outcome, adjusted HR = 1.21 (95% CI: 0.64-2.30). Further adjustment for simulated confounders positively associated with periodontitis and diabetes greatly attenuated the association or explained it away entirely (HR = 1). In models using diabetes as the exposure and incident periodontitis as the outcome, adjusted HR = 1.35 (95% CI: 0.79-2.32). After further adjustment for simulated confounders, the lower bound of the simulation interval never reached the null value (HR ≥ 1.03).

CONCLUSIONS

Presence of unmeasured confounding does not explain observed associations between pre-existing diabetes and incident periodontitis. However, presence of weak unmeasured confounding eliminated observed associations between pre-existing periodontitis and incident diabetes. These results clarify the bidirectional periodontitis-diabetes association.

Quantitative tooth mobility evaluation based on intraoral scanner measurements

BACKGROUND

Tooth mobility assessment is subjective and current techniques require the translation of a continuous variable to a categorical variable based on the perception of the examiner. The aim of this study was to evaluate the reliability of a novel technique to assess tooth mobility.

METHODS

Three experienced periodontists were asked to push tooth #16 into a buccal position to in a typodont model with different mobility (M1-M2). Tooth position was obtained using an intraoral scanner and files were compared in metrology software. Mobility was calculated at three reference points at the cervical (C), middle (M), and occlusal (O) regions of the buccal surface of the tooth to determine the linear deviation in the three axes (x, y, and z). Reliability was determined by intraclass-correlation coefficient, differences between M1 and M2 determined by t test, and the analysis of variance (ANOVA) was used to compare the data at the C-M-O regions.

RESULTS

Excellent reliability was assessed by Cronbach alpha >0.9 on the x-y-z axes for both mobility tested, except for M1-C X (0.85), M1-M Y (0.89), and M2-M Z (0.89). The correlation between the examiners demonstrated excellent (˃0.90) or good (0.75˃ x ˂0.90) consistency, except for M1-C Y (0.73; examiner 1 to 2) and M1-M X (0.69; examiners 1 to 3). Significant changes were detected in all axes at the three reference points comparing M1 and M2, and a similar proportional change was observed between O-M-C reference points for M1 and M2.

CONCLUSION

A novel technique to assess tooth mobility based on intraoral scanner measurements provided reliable data in an in vitro experiment.

Gingival Recession and Localized Aggressive Periodontitis Among HIV-infected Children and Adolescents Receiving Antiretroviral Therapy

BACKGROUND

Limited information is available on gingival recession or localized aggressive periodontitis among HIV-infected children and adolescents. This study reports on the prevalence of these conditions among children and adolescents receiving antiretroviral therapy (ART).

METHODS

A cross-sectional study on HIV-infected children and adolescents attending a Pediatric HIV clinic in Gauteng, South Africa, between January 2013 and June 2016. Patients received an oral examination and oral hygiene instructions, irrespective of oral- or dental-related complaints. Hard and soft tissue pathology was managed and recorded, together with relevant demographic and clinical data. Statistical analysis was performed in Stata 14 with P < 0.05 as significant.

RESULTS

A total of 554 children and adolescents 5-19 years of age (median age: 12.2 years; interquartile range: 10.3-14.9) were included, of whom 78 (14.1%) presented with gingival recession on permanent mandibular incisors and/or localized aggressive periodontitis of molar teeth. Multivariable logistic regression revealed that patients with gingival recession and aggressive periodontitis had a significantly shorter duration of ART and were more likely to have suboptimal HIV control (CD4 count ≤500 cells/µL and/or HIV viral load ≥50 copies/mL) and be on advanced ART regimens after virologic failure on first- and second-line treatment.

CONCLUSIONS

The results emphasize the importance of oral health care among HIV-infected children and adolescents from the onset, to prevent and manage conditions that could result in tooth loss and permanent disfigurement. This is of particular importance in the presence of virologic failure and immunosuppression.

Simulation study of misclassification bias in association studies employing partial-mouth protocols

AIM

To simulate the exposure misclassification bias potential in studies of perio-systemic disease associations due to the use of partial-mouth recording (PMR) protocols.

METHODS

Using data from 640 participants in the Dental Longitudinal Study, we evaluated distributions of clinical periodontitis parameters to simulate hypothetical outcome probabilities using bootstrap sampling. Logistic regression models were fit using the hypothetical outcome as the dependent variable. Models were run for exposure classifications based on full-mouth recording (FMR) and PMR protocols over 10,000 repetitions.

RESULTS

The impact of periodontitis exposure misclassification was dependent on periodontitis severity. Per cent relative bias for simulated ORs of size 1.5, 2 and 4 ranged from 0% to 30% for the effect of severe periodontitis. The magnitude and direction of the bias was dependent on the underlying distribution of the clinical parameters used in the simulation and the size of the association being estimated. Simulated effects of moderate periodontitis were consistently biased towards the null.

CONCLUSION

Exposure misclassification bias occurring through the use of PMR protocols may be dependent on the sensitivity of the classification system applied. Using the CDC-AAP case definition, bias in the estimated effects of severe disease was small, on average. Whereas effects of moderate disease were underestimated to a larger degree.

Incisor malalignment and the risk of periodontal disease progression

INTRODUCTION

The objective of this study was to investigate the association between incisor crowding, irregularity, and periodontal disease progression in the anterior teeth.

METHODS

Data collected over 35 years from men enrolled in the Veterans Affairs Dental Longitudinal Study included information concerning pocket depth and alveolar bone loss. Plaster casts of the maxillary (n = 400) and mandibular (n = 408) arches were available for baseline measurements. Periodontal disease in the anterior teeth was defined as per arch sum of pathologic pocket depth and sum of teeth with any alveolar bone loss in the anterior sextants. Incisor malalignment status was defined by the anterior tooth size-arch length discrepancy index and Little's Irregularity Index. Adjusted mixed effects linear models computed the beta (β) estimates and 95% confidence intervals (95% CI) of the amounts of change in periodontal disease outcomes by the level of malalignment.

RESULTS

In the anterior maxillary arch, crowding and spacing were significantly associated with an increased per-arch sum of pathologic pocket depth (β, 0.70 mm; 95% CI, 0.20-1.21, and β, 0.49 mm; 95% CI, 0.06-0.91, respectively). In the anterior mandibular arch, incisor crowding and irregularity were significantly associated with an increased per-arch sum of pathologic pocket depth (mild crowding: β, 0.47 mm; 95% CI, 0.01-0.93; severe irregularity: β, 0.94 mm; 95% CI, 0.50-1.38), and the sum number of teeth with alveolar bone loss (mild and moderate-to-severe crowding: β, 0.45 teeth; 95% CI, 0.08-0.82; and β, 0.45 teeth; 95% CI, 0.13-0.83, respectively; moderate irregularity: β, 0.34 teeth; 95% CI, 0.06-0.62).

CONCLUSIONS

Certain incisor malalignment traits (ie, maxillary incisor crowding, maxillary incisor spacing, mandibular incisor mild crowding, mandibular incisor moderate-to-severe crowding, mandibular incisor moderate irregularity, and mandibular incisor severe irregularity) are associated with significant periodontal disease progression.

A comparison of the periodontal status in patients with type 2 diabetes based on glycated haemoglobin levels and other risk factors

PURPOSE

The aim of this study was to compare the periodontal status in patients with type 2 diabetes based on glycated haemoglobin levels and other risk factors.

MATERIAL/METHODS

75 patients with DM2 were grouped according to glycemic control: 40 subjects with HbA1c<7.0% and 35 subjects with HbA1c≥7.0%. We performed measurements of HbA1c, C-reactive protein (CRP), Approximal Plaque Index (API), Gingival Severity Index (GSI), tooth mobility (TM) as well as periodontal parameters such as probing depth (PD) and clinical attachment level (CAL). Age, gender and duration of the disease were analyzed too.

RESULTS

No significant differences in PD, CAL, API, GSI and TM were found between the analyzed groups. HbA1c positively correlated with CRP (p=0.046) and the duration of DM2 (p=0.012) but not with the periodontal parameters. Patients' age was positively correlated with both the duration of DM2 (p=0.002) and CAL (p=0.034). Regardless of HbA1c, men had significantly worse periodontal parameters compared to women (respectively: PD 2.73mm vs. 2.18mm, p=0.01; CAL 3.84mm vs. 2.54mm, p=0.005; proportion of deep pockets 9.06% vs. 2.97%, p=0.01; proportion of teeth with grade 2 mobility 9.14% vs. 2.8%, p=0.02).

CONCLUSIONS

The selected group of patients attending the Diabetes Outpatient Clinic showed a similar periodontal status with regard to glycated haemoglobin levels and other risk factors except gender. Male gender turned out to be a significant risk factor for periodontal disease in patients with type 2 diabetes mellitus.

The influence of prevalent cohort bias in the association between periodontal disease progression and incident coronary heart disease

PURPOSE

In longitudinal studies, the onset of the index condition (e.g. exposure) does not always coincide with the start of a study's observation period, leading to the possibility of bias in estimation that derives from studying prevalent exposure rather than new exposure. We investigate the possible role of this bias in the relationship between periodontitis progression and coronary heart disease (CHD) among a cohort of men participating in the Veterans Administration Dental Longitudinal Study.

METHODS

At baseline, there were 298 men with existing (i.e., prevalent) periodontitis. During follow-up, routine dental inspection identified 163 new (i.e., incident) cases of periodontitis. Change in mean alveolar bone loss score (MBLS) served as the measure of disease progression. Tabular analyses were performed to obtain crude, stratified, and adjusted measures of the association for periodontitis cases overall and separately for prevalent and incident cases. Potential bias was evaluated by comparing estimates across these subcohorts.

RESULTS

Among all periodontitis cases, increasing MBLS was associated with increasing risk of CHD event. Subdividing periodontal cases into new and prevalent cases revealed that the relationship was most pronounced among incident periodontitis cases (incident rate ratio for MBLS change >0.5 = 5.4), compared with prevalent cases (incident rate ratio for MBLS change >0.5 = 2.5).

CONCLUSIONS

Studying prevalent cases of periodontitis underestimates the association between incidence periodontitis and CHD.

Coffee consumption and periodontal disease in males

BACKGROUND

Coffee is a major dietary source of antioxidants as well as of other anti-inflammatory factors. Given the beneficial role of such factors in periodontal disease, whether coffee intake is associated with periodontal disease in adult males was explored.

METHODS

Existing data collected by a prospective, closed-panel cohort study of aging and oral health in adult males was used. Participants included the 1,152 dentate males in the Veterans Affairs (VA) Dental Longitudinal Study who presented for comprehensive medical and dental examinations from 1968 to 1998. Mean age at baseline was 48 years; males were followed for up to 30 years. Participants are not VA patients; rather, they receive their medical and dental care in the private sector. Periodontal status was assessed by probing depth (PD), bleeding on probing, and radiographic alveolar bone loss (ABL), measured on intraoral periapical radiographs with a modified Schei ruler method. Moderate-to-severe periodontal disease was defined as cumulative numbers of teeth exhibiting PD ≥4 mm or ABL ≥40%. Coffee intake was obtained from participant self-reports using the Cornell Medical Index and food frequency questionnaires. Multivariate repeated-measures generalized linear models estimated mean number of teeth with moderate-to-severe disease at each examination by coffee intake level.

RESULTS

It was found that higher coffee consumption was associated with a small but significant reduction in number of teeth with periodontal bone loss. No evidence was found that coffee consumption was harmful to periodontal health.

CONCLUSION

Coffee consumption may be protective against periodontal bone loss in adult males.

Changes in body weight and adiposity predict periodontitis progression in men

Most studies linking obesity and periodontal disease have been cross-sectional in design. We examined whether gains in body weight, waist circumference, and arm fat area are associated with periodontitis progression in 893 non-diabetic men followed for up to four decades in the prospective VA Dental Longitudinal Study. Probing pocket depth (PPD) was measured by calibrated examiners. Repeated-measures generalized linear models estimated the mean cumulative numbers of teeth with PPD events (PPD > 3 mm) at each dental examination and the slopes associated with increasing numbers of affected teeth over time. Means were adjusted for baseline PPD, education, and cigarette pack-years, and time-dependent values of age, mean plaque score, cigarette packs/day, brushing, and flossing. Men who were overweight at baseline and gained weight most rapidly (> 0.19 kg/yr or ~15 lb during follow-up) had significantly more PPD events than men in the lowest tertile of weight gain (≤ -0.05 kg/yr). Overweight men whose waist circumference increased > 0.14-0.39 or > 0.39 cm/yr experienced more PPD events than men in the lowest tertile (≤ 0.14 cm/yr). Increase in arm fat area was associated with disease progression in normal-weight men. These results suggest that tracking adiposity changes with easily obtained anthropometric measures may help predict risk of periodontitis progression.

Tooth loss and periodontal disease predict poor cognitive function in older men

OBJECTIVES

To determine whether rates of tooth loss, periodontal disease progression, and caries incidence predict cognitive decline in men.

DESIGN

Prospective study.

SETTING

Community-dwelling men enrolled in the Veterans Affairs Dental Longitudinal Study.

PARTICIPANTS

Five hundred ninety-seven dentate men aged 28 to 70 at study baseline who have been followed up to 32 years.

MEASUREMENTS

Oral examinations were conducted approximately every 3 years. Periodontal disease measures included probing pocket depth and radiographic alveolar bone height. Participants underwent cognitive testing beginning in 1993. Low cognitive status was defined as less than 25 points or less than 90% of the age- and education-specific median on the Mini-Mental State Examination (MMSE) and less than 10 points on a spatial copying task.

RESULTS

Each tooth lost per decade since the baseline dental examination increased the risks of low MMSE score (hazard ratio (HR)=1.09, 95% confidence interval (CI)=1.01-1.18) and low spatial copying score (HR=1.12, CI=1.05-1.18). Risks were greater per additional tooth with progression of alveolar bone loss (spatial copying: HR=1.03, CI=1.01-1.06), probing pocket depth (MMSE: HR=1.04, CI=1.01-1.09; spatial copying: HR=1.04, CI=1.01-1.06), and caries (spatial copying: HR=1.05, CI=1.01-1.08). Risks were consistently higher in men who were older than 45.5 at baseline than in younger men.

CONCLUSION

Risk of cognitive decline in older men increases as more teeth are lost. Periodontal disease and caries, major reasons for tooth loss, are also related to cognitive decline.

Periodontitis and incidence of cerebrovascular disease in men

OBJECTIVE

To identify associations between periodontitis and incidence of cerebrovascular disease.

METHODS

We analyzed data of 1,137 dentate men in the Veterans Affairs Normative Aging and Dental Longitudinal Study who were followed with triennial medical/dental exams for up to 34 years (mean, 24 years). We evaluated incidence of cerebrovascular events consistent with stroke or transient ischemic attack in relation to mean radiographic alveolar bone loss (a measure of periodontitis history) and cumulative periodontal probing depth (a measure of current periodontal inflammation). Cox proportional hazards models were fit controlling for age, baseline socioeconomic status, and time-varying effects of established cardiovascular risk factors.

RESULTS

Eighty incident cases of cerebrovascular disease occurred from 27,506 person-years. Periodontal bone loss was significantly associated with an increased hazard rate (HR) of cerebrovascular disease (HR, 3.52; 95% confidence interval [CI], 1.59-7.81 comparing highest to lowest bone loss category; p for trend, <0.001). There was a stronger effect among men aged <65 years (HR, 5.81; 95% CI, 1.63-20.7) as compared with men aged > or =65 years (HR, 2.39; 95% CI, 0.91-6.25). Periodontal probing depth was not associated with a significantly increased rate of cerebrovascular disease in the combined or age-stratified analyses.

INTERPRETATION

These results support an association between history of periodontitis-but not current periodontal inflammation-and incidence of cerebrovascular disease in men, independent of established cardiovascular risk factors, particularly among men aged <65 years.

Age-dependent associations between chronic periodontitis/edentulism and risk of coronary heart disease

BACKGROUND

Several epidemiological studies have suggested periodontitis as a risk factor for coronary heart disease (CHD), but results have been inconsistent.

METHODS AND RESULTS

We evaluated the association between clinical and radiographic measures of periodontitis, edentulism, and incident CHD (angina, myocardial infarction, or fatal CHD) among 1203 men in the VA Normative Aging and Dental Longitudinal Studies who were followed up with triennial comprehensive medical and dental examinations up to 35 years (median 24 years). Cox proportional hazards models with time-varying effects of exposure and potential confounders were fit. We found a significant dose-dependent association between periodontitis and CHD incidence among men < 60 years of age (hazard ratio 2.12, 95% confidence interval 1.26 to 3.60 comparing highest versus lowest category of radiographic bone loss, P for trend=0.02), independent of age, body mass index, smoking, alcohol intake, diabetes mellitus, fasting glucose, total cholesterol, high-density lipoprotein cholesterol, triglycerides, hypertension, systolic and diastolic blood pressure, education, marital status, income, and occupation. No association was found among men > 60 years of age. Similar results were found when the sum of probing pocket depths was used as a measure of periodontitis. Among men > or = 60 years of age, edentulous men tended to have a higher risk of CHD than dentate men in the lowest bone loss (hazard ratio 1.61, 95% confidence interval 0.95 to 2.73) and lowest pocket depth (hazard ratio 1.72, 95% confidence interval 1.03 to 2.85) categories, independent of confounders.

CONCLUSIONS

Chronic periodontitis is associated with incidence of CHD among younger men, independent of established cardiovascular risk factors.

Gingival bleeding on repeat probing after different time intervals in plaque-induced gingivitis

The aim of this study was to assess agreement and association of gingival bleeding after repeated probing at different time intervals in subjects with gingivitis. Twenty adults participated. Periodontal probing (P approximately 1.27 MPa) was conducted at six sites of every tooth present. Probing was repeated in different quadrants immediately after the first probing (T0), after 1 h (T1), 4 h (T4), and 24 h (T24). A total of 3,459 sites were probed twice. The mean proportion of sites bleeding on probing (BOP) was 0.23 (standard deviation 0.08, range 0.10-0.41). Probing itself had a significant effect on the results of repeated probing. For T0 through T24, respective mean differences of proportions were 0.04, 0.04, 0.01, and -0.03. Ninety-five percent repeatability coefficients of proportions were 0.17-0.18. Estimates of overall kappa were 0.390, 0.234, 0.233, and 0.046 for T0 through T4, respectively. Adjusted two-level binary response models revealed odds ratios (95% confidence interval) for BOP at T0 through T4 of 6.52 (4.34, 9.80), 3.23 (2.19, 4.76), 3.80 (2.63, 5.50), and 2.68 (1.85, 3.89). It was concluded that a certain degree of agreement of site-specific bleeding scores in subjects with plaque-induced gingivitis could be observed only if probing was repeated at once. Adjusted associations between repeat BOP were weak in general, but strongest immediately after first probing. There appears to be a significant effect of probing itself, which may last for more than 1 h, whereas 24-h results are obtained under different conditions.

Longitudinal validation of a risk calculator for periodontal disease

BACKGROUND

Risk assessment and utilization of the results are important components of prevention, diagnosis and treatment of periodontal diseases. Risk assessment is relatively new to dentistry. Currently risk is assessed by subjective evaluation and results vary widely among clinicians. We have developed a computer-based risk assessment tool, the Periodontal Risk Calculator (PRC), for objective, quantitative assessment of risk. The purpose of the study reported here was to evaluate the accuracy and validity of this tool.

METHODS

Clinical records and radiographs of 523 subjects enrolled in the VA Dental Longitudinal Study of Oral Health and Disease, covering a period of 15 years, were used. Information from baseline examinations was entered into the risk calculator and a risk score on a scale of l-5 for periodontal deterioration was calculated for each subject. Actual periodontal status in terms of alveolar bone loss determined using digitized radiographs, and tooth loss determined from the clinical records, was assessed at years 3, 9 and 15. The strength of the association between risk prediction and actual outcome was determined statistically.

RESULTS

The risk scores were strong predictors of future periodontal status measured as worsening severity and extent of alveolar bone loss and tooth loss, especially loss of periodontally affected teeth. Over the entire 15-year period, risk scores consistently ranked groups from least to most bone loss and tooth loss. Risk groups differed greatly from one another. By year 3, the incidence rate of bone loss of group 5 was 3.7-fold greater than for group 2, and by year 15, the loss of periodontally affected teeth was 22.7-fold greater than for group 2 (p<0.001). By year 15, 83.7% of subjects in risk group 5 had lost one or more periodontally affected teeth compared to 20.2% of subjects in group 2.

CONCLUSIONS

Risk scores calculated using the PRC and information gathered during a standard periodontal examination predict future periodontal status with a high level of accuracy and validity. Use of the risk assessment tool over time may be expected to result in more uniform and accurate periodontal clinical decision-making, improved oral health, reduction in the need for complex therapy and reduction in health-care cost.

Vitamin D Receptor Alleles, Periodontal Disease Progression, and Tooth Loss in the VA Dental Longitudinal Study

BACKGROUND

The relationship between the vitamin D receptor (VDR) genotype and periodontal disease is not known. This study compared periodontal disease progression among polymorphisms of 2 VDR genes in men in the VA Dental Longitudinal Study.

METHODS

Subjects were 125 medically healthy, middle-aged men who had serial oral examinations over a mean 23-year period. Probing depth, gingival bleeding on probing, clinical attachment loss (CAL), and alveolar bone loss (ABL) from radiographs were measured at each examination. Progression of periodontal disease was defined as the percentage of teeth per decade that increased ABL by > or = 40%, and the percentage of teeth per decade that developed CAL > or = 5 mm. ApaI and TaqI polymorphisms were determined from buffy coat cells following polymerase chain reaction (PCR) amplification. Mean changes in oral status were adjusted for baseline values of smoking status, number of teeth present, and periodontal status by analysis of covariance.

RESULTS

Genotype distributions were 41 AA, 58 Aa, 26 aa; and 53 TT, 46 Tt, 26 tt. The AA genotype showed the highest rates of progression of ABL (5 +/- 1% versus 1 +/- 1% and 2 +/- 1% teeth in Aa and aa, respectively; P = 0.03), CAL (37 +/- 4% versus 17 +/- 4% and 27 +/- 6% teeth; P = 0.004), and tooth loss (2 +/- 0.3 versus 1 +/- 0.3 and 1 +/- 0.4 teeth; P = 0.04). When genotype combinations were examined, progression of ABL, CAL, and tooth loss was highest in the AATT and AATt genotypes.

CONCLUSIONS

The ApaI polymorphism of the VDR gene is associated with oral bone loss, clinical attachment loss, and tooth loss in older men. Analysis of the VDR alleles may prove useful for predicting periodontal disease.

Validation of self-reported oral health measures

OBJECTIVES

To assess the validity of self-reported oral disease and health care measures in two populations.

METHODS

Telephone interviews were conducted among a subsample of participants in the VA Dental Longitudinal Study (VADLS) asking them about periodontal disease status and treatment. Radiographic alveolar bone loss evaluated at all the interproximal sites was used as the standard. A separate study was carried out among first-time patients at the Harvard School of Dental Medicine (HSDM) student clinic. Self-reported measures were obtained by a self-administered questionnaire and compared with clinical and radiograph examinations. The measures used were based on published work that demonstrated good validity of self-reported periodontal measures among health professionals.

RESULTS

Among 145 VADLS participants, self-reports of periodontal disease showed a good specificity (59.8%-90.7%), but low sensitivity (17.7%-64.7%). Among 58 HSDM patients, the self-reported numbers of remaining teeth, fillings, root canal therapy, and prosthesis were strongly correlated with clinical records (r = 0.74-1.0); self-report was less accurate for measures of periodontal disease (r = 0.56) and decayed teeth (r = 0.47).

CONCLUSIONS

Self-reports provide reasonably valid estimates for numbers of remaining teeth, fillings, root canal therapy, and fixed and removable prostheses. However, they appear to be less useful for the assessment of dental caries and periodontal disease in the two populations we have studied. There remains a need and potential to further develop self-report oral health measures that are valid for use in large population studies. Such self-report measures would yield great cost and time savings.

Validity and accuracy of a risk calculator in predicting periodontal disease

BACKGROUND

Research on the pathobiology of periodontal diseases has increased our knowledge of these diseases and is fostering a transition from the repair model to the medical or wellness model of periodontal care. Successful application of the wellness model depends on an accurate and valid assessment of disease risk, as well as institution of risk reduction as an integral part of prevention and treatment. A computer-based risk assessment tool has been developed.

METHODS

The authors reviewed clinical records and radiographs of 523 subjects enrolled in the Veterans Affairs Dental Longitudinal Study to evaluate the validity of risk prediction using the computer-based tool. Data from baseline examinations was entered into the risk calculator, and a risk score on a scale from 1 (lowest risk) to 5 (highest risk) was calculated for each subject to predict periodontal deterioration. Actual periodontal status in terms of alveolar bone loss (determined from digitized radiographs) and tooth loss (determined from clinical records) was assessed at years 3, 9 and 15. The authors determined the statistical strength of the association between risk prediction and actual outcome.

RESULTS

The risk scores were strong predictors of periodontal status, as measured by alveolar bone loss and loss of periodontally affected teeth. Risk scores consistently ranked risk score groups from least to most bone loss and tooth loss. Compared with a risk score of 2, the relative risk of tooth loss was 3.2 for a risk score of 3, 4.5 for a risk score of 4 and 10.6 for a risk score of 5.

CONCLUSIONS AND PRACTICE IMPLICATIONS

Use of the risk assessment tool over time may result in more uniform and accurate periodontal clinical decision-making, improved oral health, reduction in the need for complex therapy, reduction in health care costs and a hastening of the transition from a repair model to a wellness model of care.

A longitudinal study of the association between tooth loss and age-related hearing loss

The purpose of this study was to investigate cross-sectional and longitudinal associations between hearing acuity and tooth loss in 1156 US veterans taking part in the Veterans Affairs' Normative Aging (NAS) and Dental Longitudinal (DLS) Studies in the Boston, MA, area. The mean age was 48 years (SD = 8.9), 5.3% were edentulous, and 15.4% had < 17 teeth at baseline. Hearing acuity was determined by puretone, air- and bone-conduction audiometry, and speech discrimination tests at triennial examinations over a 20-year follow-up period. Hearing decline was defined as a change from baseline in the average puretone air-conduction thresholds of > or = 20 dB at 0.25, 0.5, 1, 2, 3, 4, 6, and 8 kHz. The explanatory variables of interest were change since baseline in dentate status (cut points at < 1, < 17, and < 20 teeth), and in the number of teeth lost (linear). Linear and logistic regression models--which controlled for baseline audiological status, age, air-bone gap, and otoscopic examination at current visit--showed that subjects who went from having > or = 17 to < 17 teeth had 1.64 times (95% CI, 1.24-2.17) as high odds of having hearing decline as those with no change in their dentate status. For every tooth lost since baseline, there was a 1.04 times as high odds (95% CI, 1.02-1.06) for hearing decline, when additional baseline and time-varying covariates were taken into account in the model.

Alveolar bone loss and tooth loss in male cigar and pipe smokers

BACKGROUND

While cigarette smoking is recognized as being detrimental to oral health, the effects of cigar and pipe smoking on tooth-loss risk, alveolar bone loss and periodontal disease are not known. The authors conducted this study to determine whether cigar and pipe smokers were at greater risk of experiencing tooth loss and alveolar bone loss than were nonsmokers.

METHODS

The authors studied 690 dentate men who participate in the Veterans Affairs Dental Longitudinal Study. Subjects are not VA patients, and they receive medical and dental care in the private sector. A board-certified periodontist conducted clinical examinations triennially for 23 years. These examinations included the number of teeth remaining, number of decayed and filled surfaces per tooth, and indicator scores for plaque, calculus, pocket probing depth, gingival bleeding and tooth mobility. Alveolar bone loss was assessed at each examination on intraoral periapical radiographs using the Schei ruler method, which measures loss of bone height in 20 percent increments. Multivariate analyses of tooth-loss rates and alveolar bone loss controlled for demographic and oral hygiene measures.

RESULTS

The relative risk, or RR, of tooth loss compared with that of nonsmokers was significantly elevated in cigar smokers (RR = 1.3, 95 percent confidence interval, or CI, = 1.2, 1.5), pipe smokers (RR = 1.6, 95 percent CI = 1.4, 1.9) and cigarette smokers (RR = 1.6, 95 percent CI = 1.5, 1.7). The percentages of mesial and distal sites with moderate-to-severe progression of alveolar bone loss (a change of 40 percent or more from baseline) were 8 +/- 1 percent (mean +/- standard error) in nonsmokers, 16 +/- 3 percent in cigar smokers (P < .05), 13 +/- 4 percent in pipe smokers (P = .17), and 16 +/- 3 percent in cigarette smokers (P < .001). Pipe and cigar smokers did not differ significantly from nonsmokers with respect to the percentage of sites at baseline with moderate-to-severe scores for calculus, pocket probing depth, gingival bleeding or tooth mobility. Pipe smokers had fewer sites with moderate-to-severe plaque accumulation than did nonsmokers (7 +/- 11 vs. 13 +/- 17, P < .05).

CONCLUSIONS

The authors found that men who smoke cigars or pipes were at increased risk of experiencing tooth loss. Cigar smokers also were at increased risk of experiencing alveolar bone loss. These elevations in risk are similar in magnitude to those observed in cigarette smokers.

CLINICAL IMPLICATIONS

The increases in risk related to cigar and pipe smoking provide a strong rationale for targeting smoking prevention and smoking cessation programs to smokers of all tobacco products.

Comparison of health behaviour and oral/medical conditions in non-insulin-dependent (type II) diabetics and non-diabetics

One hundred and two dentate patients with type II diabetes mellitus and 98 non-diabetic subjects were examined for oral conditions and metabolic state. Self-reported health behaviour was analysed. From factor analysis four factors emerged: general health behaviour (GHB), perceived fatigue (PF), diet control (DC) and regular diet (RD). In diabetics PF, DC and RD were significantly higher than that in non-diabetics. Patients with diabetes were more likely to control their disease through a programme of decreased kilojoule intake leading to weight management. However, they tended to tire. The mean gingivitis index was significantly higher (p < 0.01) among diabetics (2.39) than among non-diabetics (1.99). The number of missing teeth was significantly higher (p < 0.01) for diabetics (6.7) when compared with non-diabetics (4.3). On the other hand, aetiological factors (plaque, calculus) and the level of dental health behaviour as expressed in the HU-DBI scores were similar. Probing pocket depth did not differ statistically between groups. The increasing number of missing teeth in diabetics may primarily result from severe periodontitis with tooth mobility or deep pockets. Findings in this study suggest that the difference in the severity of periodontitis between diabetics and non-diabetics was significant although aetiological factors and the level of dental health behaviour were similar.

The association between alveolar bone loss and pulmonary function: the VA Dental Longitudinal Study

The effect of oral conditions on medical outcomes is not well understood. The purpose of this epidemiological investigation was to examine whether the risk for chronic obstructive pulmonary disease (COPD) is enhanced among individuals with a history of periodontal disease as assessed by radiographic alveolar bone loss (ABL). Subjects were selected from the VA Dental Longitudinal Study, a long-term study of aging and health in male veterans who were medically healthy at baseline. Subjects are not VA patients. Those subjects with a forced expiratory volume in 1 second (FEV1) less than 65% of predicted volume were categorized as having COPD. ABL was assessed by using full-mouth series periapical films measured by a Schei ruler. Bone loss at each interproximal site was measured in 20% increments, and the mean whole-mouth bone loss score was calculated. Logistic regression analysis was used to determine the independent contribution of bone loss measurement at baseline to the subsequent risk of developing COPD over a 25-year follow-up period. Covariates included measures of smoking, height, age, education, and alcohol consumption. Of the 1,118 medically healthy dentate men at baseline, 261 subsequently developed COPD. We found that ABL status at baseline was an independent risk factor for COPD, with subjects in the worst population quintile of bone loss (mean ABL > 20% per site) found to be at significantly higher risk (OR = 1.8; 95% CI = 1.3, 2.5). The results of this analysis indicate that increased ABL is associated with an increased risk for COPD

Periodontal disease and mortality from all causes in the VA Dental Longitudinal Study

(The role that oral conditions may play as risk factors or indicators for various medical outcomes, including mortality, is not well understood. We have examined the relationship of periodontal disease to mortality from all causes in the VA Dental Longitudinal Study and Normative Aging Study, a prospective cohort study of the determinants of disease in aging men. Subjects were screened for entry into the closed-panel cohort in the mid-1960s, based on good medical health. They are not VA patients. We have used proportional hazards regression models to assess the relationship of periodontal health status at baseline to all-cause mortality over a 25+-year follow-up period. A total of 804 dentate subjects who were alive and medically healthy through their first follow-up exam were used in the analysis; of these, 166 died during subsequent follow-up through December 1996. Survival was calculated in years from baseline exam to death or censoring (most recent study examination date). To define periodontal health status at baseline, we separately used radiographic alveolar bone loss (ABL) (person-level scores of mean whole-mouth % ABL, measured with a Schei ruler using full-mouth series of periapical films) and periodontal clinical probing depths. Covariates included age at baseline, and assessments at baseline of smoking and alcohol use, education, body mass index, serum cholesterol, white blood cell count, blood pressure, family history of heart disease, and number of teeth present. We found that periodontal status at baseline was a significant and independent predictor of mortality in this cohort, while controlling for other recognized predictors in multivariate models. For each 20% increment in mean whole-mouth ABL, the subject's risk of death increased by 51% (RR = 1.51; 95% CI = 1.11-2.04). The increase in risk attributable to periodontal status was found to be similar in magnitude to, and independent of that attributable to cigarette smoking in this cohort. While the increased risk due to smoking was 1.52-fold (95% CI = 1.06-2.19), being in the population quintile with highest ABL scores (i.e., worst periodontal status) was associated with a 1.85 fold increase in risk (95% CI = 1.25-2.74) using multivariate analyses. The hypothesis that chronic oral infections, as in periodontitis, may have important systemic sequelae merits further investigation in prospective controlled studies.

Smoking, smoking cessation, and tooth loss

Smoking is associated with an increased risk of tooth loss, but it is not known if this risk decreases significantly when individuals quit smoking. The objectives of this study were to describe the rates of tooth loss by smoking status in two populations of medically healthy men and women. Among the men, rates of tooth loss and edentulism in relation to smoking cessation were also evaluated. The subjects were drawn from a group of 584 women (aged 40 to 70) recruited from the Boston, MA, area and a separate population of 1231 male veterans (aged 21 to 75) who participated in the VA Dental Longitudinal Study in Boston. In cross-sectional baseline analyses, current cigarette smokers of either sex had significantly more missing teeth than never-smokers or former smokers. Former smokers and pipe or cigar smokers tended to have an intermediate number of missing teeth. Current male smokers had more teeth with calculus, but the differences in plaque, tooth mobility, probing depth > 2 mm, filled and decayed teeth, and bleeding on probing by smoking history were not significant. Prospective observations of 248 women (mean follow-up time = 6 +/- 2 years) and 977 men (mean = 18 +/- 7 years) indicated that individuals who continued to smoke cigarettes had 2.4-fold (men) to 3.5-fold risk (women) of tooth loss compared with non-smokers. The rates of tooth loss in men were significantly reduced after they quit smoking cigarettes but remained higher than those in non-smokers. Men who smoked cigarettes had a 4.5-fold increase in risk of edentulism, and this risk also decreased upon smoking cessation. These findings indicate that the risk of tooth loss is greater among cigarette smokers than among non-smokers. Smoking cessation significantly benefits an individual's likelihood of tooth retention, but it may take decades for the individual to return to the rate of tooth loss observed in non-smokers.

The achievement and maintenance of inter-examiner consistency in the assessment of plaque and gingivitis during a multicentre study based in general dental practices

This study set out to demonstrate that it was possible to train general dental practitioners (gdps) to achieve and maintain high levels of inter-examiner consistency in the use of simple periodontal indices over a 12-month period. The gdps were trained by one trainer in the use of the plaque index (PII) and a modified version of the gingival index (mGI) which assessed gingival bleeding only. All the gdps underwent intensive training and employed a technique, when assessing inter-examiner consistency in the use of the PII, such that the 1st examiner did not disturb in situ plaque from 50% of the circumference of a tooth. The problem of variation due to repeat probing, when assessing inter-examiner consistency for mGI, was overcome by one examiner lightly probing gingival margins and both examiners scoring the results. The problems relating to the multicentre nature of the study included: distance between the centres, the need for strict adherence to the study protocol, consistency in the use of forms and instruments, in the application of periodontal indices, and of inclusion and exclusion criteria. Techniques for overcoming these problems included: the planning and application of a coherent study design, which employed simple indices, a detailed protocol, the recruitment of very well-motivated gdps of similar age and experience as examiners, the recruitment of an experienced trainer who trained the gdps thoroughly and monitored their performance throughout the study, and repeat visits to the practices involved to explain the nature of the study to all their staff members. Initially, the gdps achieved inter-examiner kappa scores of 0.78-0.85 (mean 0.81) for PII and of 0.73-0.94 (mean 0.87) for mGI when assessing 168 sites for each variable. During the following 12 months, individual kappa scores, assessed every 3 months at 42 sites, ranged from 0.51-0.90 for PII and from 0.73-1.00 for mGI. Mean kappa for PII scores achieved by the five gdps fell during the study from 0.81 to 0.76, whereas that for mGI rose from 0.87 to 0.92. It is concluded that it is possible to train gdps to achieve high levels of inter-examiner consistency in the use of PII and mGI and for these high levels to be maintained during a 12-month multicentre study.

Periodontal disease and cardiovascular disease

It is our central hypothesis that periodontal diseases, which are chronic Gram-negative infections, represent a previously unrecognized risk factor for atherosclerosis and thromboembolic events. Previous studies have demonstrated an association between periodontal disease severity and risk of coronary heart disease and stroke. We hypothesize that this association may be due to an underlying inflammatory response trait, which places an individual at high risk for developing both periodontal disease and atherosclerosis. We further suggest that periodontal disease, once established, provides a biological burden of endotoxin (lipopolysaccharide) and inflammatory cytokines (especially TxA2, IL-1 beta, PGE2, and TNF-alpha) which serve to initiate and exacerbate atherogenesis and thromboembolic events. A cohort study was conducted using combined data from the Normative Aging Study and the Dental Longitudinal Study sponsored by the United States Department of Veterans Affairs. Mean bone loss scores and worst probing pocket depth scores per tooth were measured on 1,147 men during 1968 to 1971. Information gathered during follow-up examinations showed that 207 men developed coronary heart disease (CHD), 59 died of CHD, and 40 had strokes. Incidence odds ratios adjusted for established cardiovascular risk factors were 1.5, 1.9, and 2.8 for bone loss and total CHD, fatal CHD, and stroke, respectively. Levels of bone loss and cumulative incidence of total CHD and fatal CHD indicated a biologic gradient between severity of exposure and occurrence of disease.

Examiner agreement on periodontal indices during dental surveys of elders

Indices used to evaluate periodontal health have been widely accepted in epidemiological studies, yet their reliability cannot be guaranteed. The aim of this study was to evaluate the reliability of periodontal indices applied on elders. 19 elderly subjects, 73-years-old on average, were examined at a 1st appointment by 2 independent examiners. They were re-examined 2 weeks later during a 2nd session. The examinations were performed in a dental chair with good illumination. Periodontal health was evaluated using the community periodontal index of treatment need, and tooth mobility was evaluated using 2 different indices. Inter and intra-examiner agreements were evaluated using kappa statistics. Taken as an overall measurement, the CPITN was a reliable assessment of periodontal treatment need in elders. Disagreement occurred mainly on the evaluation of bleeding and shallow pockets. The detection of fairly mobile teeth was reliable; however, the performance of the more sensitive scale was deceptive. it seems that, in the case of tooth mobility, a choice has to be made between sensitivity or reproducibility. It can be concluded that examiners should be trained carefully since the reliability of the CPITN and tooth mobility evaluation were good but close to a critical level for which an agreement is classified as poor.

Validity of a self-reported periodontal disease measure

OBJECTIVES

The purpose of this study was to determine the validity of a self-reported periodontal disease measure for use in the Health Professionals Follow-up Study.

METHODS

Participating dentists responded to the question "Have you had periodontal disease with bone loss?" Radiographs obtained from 140 participants were evaluated for bone loss at 32 posterior sites and used as the standard. A site was positive if it had bone loss > 2 mm and/or complete loss of crestal lamina dura. To avoid falsely classifying participants as positive, three blinded examiners independently evaluated each participant's radiographs. An a priori decision rule was used to classify a participant positive if all examiners independently assessed the same two or more sites positive.

RESULTS

The validity of the self-reported measure was good among dentists, with positive and negative predictive values of 0.76 and 0.74, respectively. Among nondentists, the self-reported measure showed discriminatory power by confirming associations with known risk factors such as age and smoking.

CONCLUSIONS

Dentists have a good perception of their periodontal status, and there is reasonable consensus among dentists regarding the threshold for defining periodontal disease. Self-reported measures might have potential for use in studies of other populations with substantial cost reduction, and deserve further evaluation.

Utilization of dental services as a risk factor for periodontitis

The relation between utilization of dental services from community dentists and the extent and severity of alveolar bone loss is reported for a panel of men followed for over 6 years. Oral health data were collected by the Department of Veterans Affairs, Dental Longitudinal Study, which began in 1969 and still continues. Participants have received regular oral examinations approximately every 3 years. A variety of oral health conditions were assessed, including plaque, calculus, gingival inflammation, probing depth, tooth mobility, clinical attachment level, and alveolar bone loss. Utilization data were abstracted from the dental records of dental offices that participants attended from 1979 through 1988. Multivariate modeling as well as comparisons of high utilizers and non-utilizers indicate that utilization of routine diagnostic and preventive services was not predictive of the extent and severity of periodontitis.

Epidemiologic study of sound surface trends in a 10-year longitudinal study

Longitudinal data of 589 men aged 30-65 yr, each followed for 10 yr, were analyzed to identify variables which may be associated with healthy tooth surface loss. A longitudinal linear growth curve model was used. As expected, older cohorts tended to have fewer sound surfaces (P < 0.02), but they also tended to have greater rates of sound surface loss (P < 0.01). Age, bone loss, number of teeth at baseline, gingivitis, pocket depth and calculus were individually correlated (P < 0.05) with the rate of sound surface loss. The number of filled or diseased surfaces at baseline was also marginally correlated (P < 0.06) with rate of sound surface loss.

Longitudinal statistical models for loss of sound surfaces

Longitudinal data of 50-yr-old men, followed for 10 yr, were analyzed to identify variables which may be associated with healthy tooth surface loss. Three types of longitudinal models were used, arriving at similar conclusions. Predictors of sound tooth surface loss with aging included pocket depth, mobility, and recession.

Meta-analysis of surgical versus non-surgical methods of treatment for periodontal disease

A meta-analysis was performed on 5 randomized controlled trials comparing surgical with non-surgical treatment for periodontal disease. The specific procedures considered were the modified Widman flap compared with scaling and root planning or curettage with anesthesia. We chose the most consistently reported outcomes, pocket depth and attachment level, for analysis. At 1 year of follow-up, surgical treatment reduced pocket depth more than non-surgical for all initial levels of disease, but by 5 years, only the deepest initial pockets (> 7 mm) showed significant improvement over non-surgically treated teeth (0.51 mm reduction, p < 0.01). Attachment level showed significantly better early results for non-surgical treatment for less diseased teeth, but by 5 years, all significant differences had disappeared. We computed quality scores following a method described by Chalmers. The mean quality score for study data analysis and presentation was 0.37 +/- 0.009 and for the study protocol, the mean quality score was 0.19 +/- 0.002. We find that this meta-analysis supports findings relating response to therapy with initial level of disease severity. We also find that the choice of outcome measure influences the choice of therapy, with surgical therapy providing greater benefit for probing depth and non-surgical therapy providing greater benefit for attachment level. These results must be viewed, however, in light of the low quality scores of the evaluated studies and the potential for bias due to lack of binding, the small mean treatment differences, and the observer measurement variability.

Evaluation of a photographic method for diagnosis of gingivitis and caries

The aim of the present study was to determine the value of a photographic method when diagnosing gingivitis and caries. 78 patients participated in the investigation. The validity of the photographic method could not be established, since the reproducibility of the clinical diagnosis was not 100%. Instead, the value of the method was determined by comparing the reproducibility of the clinical and the photographic diagnosis. For gingivitis the intra- and inter-examiner reproducibilities were best for the photographic readings. For caries the reproducibility of the clinical diagnosis was highest. The photographic method was not limited by method variation when diagnosing redness of the gingiva and caries. However, limitations due to variation were present when diagnosing gingival swelling. The paper also describes the bias reducing capacity of the photographic method.

Examiner reliability for an invasive gingival bleeding index

This investigation was undertaken to determine the intra- and inter-examiner reliability of the method of stimulation for bleeding used in the Eastman interdental bleeding index. 26 subjects were examined twice, 1 h apart, by either a single examiner or 2 examiners in each half of their mouths, for the presence bleeding after stimulation with a wooden interdental cleaner. Scores were tabulated and intra- and inter-examiner % agreements and kappa-coefficients calculated. Z-tests were performed on the pairs of agreement statistics to check for significant differences. Overall, intra-examiner agreement statistics were high (91.3% to 93.1% agreement; 0.79 to 0.86 kappa-coefficient). Further breakdowns of the data into facial and lingual sites by arch and location (anterior or posterior) resulted in similar levels of reliability, with no significant differences within examiners. The overall inter-examiner agreement statistics were good (82.8% to 87.6% agreement; 0.62-0.75 kappa coefficient). When inter-examiner data were analyzed at facial or lingual sites by arch and location, a significant difference existed in reliability for mandibular posterior lingual sites, but reliability was high in all other areas. These data demonstrate a high level of reproducibility for this method, which suggests that the Eastman interdental bleeding index is suitable for clinical trials and epidemiologic studies of interdental gingivitis.

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.

Clinical indicators of radiographically detectable dental diseases in the adult patient

A comprehensive analysis of the relationship between clinical observations in dental patients without symptoms and oral disease as detected by full-mouth and panoramic dental radiographs in a large population of patients has never been reported. Knowledge of these relationships is necessary in the design of a diagnostic decision process (clinical algorithm) that can predict which patients require dental radiographs for the diagnosis of dental caries or periodontal disease to be confirmed or refined. An accurate clinical algorithm could reduce the number of radiographs that are taken of certain routinely seen dental patients without symptoms, thus reducing unnecessary exposure x-radiation as well as potentially reducing health care costs for these patients. A sample of 602 adult men on whom a complete series of panoramic, posterior bitewing, and periapical dental radiographs and an independent oral examination were performed provided the opportunity to evaluate the relationship between clinically observed oral disease indicators and independent radiographic evidence of dental caries and periodontal disease. The analysis suggests that combinations of several clinical indicators can predict with some success which patients without symptoms will benefit most from oral radiographs. The presence of several carious lesions on oral examination was the best predictor of radiographic detection of dental caries. Clinical indicators tht appear to predict radiographic evidence of periodontal disease are clinical measures of pocket depth, mobility, and the patient's denture status. An important finding is that because of the high prevalence of gingivitis and plaque, these indicators were not related to radiographic evidence of periodontal disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Longitudinal radiographic analysis of carious lesion progression

Information on the rate at which carious lesions progress through the enamel of human teeth in an adult population was obtained from dental radiographs taken at 3-yr intervals, over a 10-yr period on 602 men. Clinical measures of calculus deposition, plaque accumulation, gingival inflammation, tooth mobility, periodontal pocket depth, and gingival recession were studied to find predictors that might be of value to the clinician for determining how frequently radiographs should be taken. We estimate that 50% of the enamel lesions on mesial and distal surfaces, if left untreated, would not progress into the dentin until 73 months had elapsed after the lesion was initiated. Significant differences in the progression rate were associated with the arch and tooth type. Patient age, number of decayed or filled surfaces, degree of gingival inflammation, amount of recession, and plaque accumulation were positively associated with more rapid caries progression, while greater numbers of teeth present were predictive of slower disease progression.

Representativeness of the "Ramfjord teeth" for epidemiologic studies of gingivitis and periodontitis

Data from the Veterans Administration Dental Longitudinal Study of 736 men each examined four times were analyzed to determine how representative the six "Ramfjord Teeth" (RT) were of the rest of the dentition for epidemiologic studies of gingivitis and periodontitis. Correlation coefficients were calculated between scores for gingival inflammation generated by the RT and scores for the teeth in the rest of the mouth; the correlation coefficients between the two scores tended to be high. Sensitivity, specificity and predictive values were calculated for periodontal pathology classified on the basis of the pocket depths of the six RT. Reliance on the RT resulted in systematic underestimation of the prevalence and incidence of deep periodontal pockets. The RT are more than adequately representative of the rest of the dentition for epidemiologic studies of gingivitis, but are inadequate surrogates of the rest of the mouth for epidemiologic studies of periodontitis.

Reliability of attachment level measurements using the cementoenamel junction and a plastic stent

Repeated measurements of attachment level appear to be important assessments in periodontal clinical trials, yet the lack of reliability for this assessment creates measurement error which in turn demands increased sample sizes or reduces the power of the test. A plastic occlusal stent has been developed as a fixed reference point to assess changes in probing depths over time and thus reflect differences in attachment levels. The advantages of this system over traditional methods have not been measured. The purpose of this study was to determine intra- and interexaminer reliability for probing depths from the stent and the CEJ. Paired measurements of attachment level using the stent produced correlation coefficients for inter- and intraexaminer readings of 0.84 and 0.76, respectively. For subgingival cementoenamel (CEJ) measurements, lower coefficients of 0.71 and 0.59 were found for inter- and intraexaminer paired readings, respectively. Thus, measurements using the stent appear to be more reliable than subgingival CEJ readings.

Comparison of manual and pressure-controlled periodontal probing

Over 25,000 sites around natural teeth in three stages of periodontal therapy (prior to instrumentation, following closed subgingival instrumentation and following surgical therapy) were independently probed by two examiners. Examiner A used a conventional periodontal probe with uncontrolled pressure. Examiner B used an identical probe tip mounted in a handle which controlled vertical probing force at 50 g. The pressure-controlled technique produced significantly deeper clinical probing measurements on the direct facial and lingual aspects of teeth regardless of the stage of periodontal therapy that had been completed. Manual probing obtained deeper measurements on the distal-lingual aspects of teeth in the posterior regions which had not received surgical therapy. The percentage match between probing depths obtained by the two methods declined as the probing depths increased. Control of vertical force during probing may provide a more objective method of monitoring periodontal status during longitudinal trials.

Design and analysis considerations for a longitudinal study of periodontal disease

Perception and concern for the health changes in our aging population led the Veterans Administration to initiate an interdisciplinary and longitudinal investigation of the aging process, the Veterans Administration Normative Aging Study, in 1963. A cohort of the 2,280 healthy men of this study self-selected to enroll in the dental longitudinal study, an investigation of oral health in these healthy males. In 1968, 1,221 men between the ages of 25 and 75 began with a baseline cycle of 5 general series of examinations, including an interim health history and survey of dietary habits; masticatory performance and taste thresholds; salivary analyses; oral cytologic and radiographic survey and comprehensive clinical data on caries and periodontal status. Design considerations for the Dental Longitudinal Study included prospective planning of specific oral variables to be recorded, and provision of collection techniques to allow for additional analyses based on a wide menu of retrospective data. The volunteer cohort was screened to obtain men who met stringent general health criteria, who represented wide socioeconomic ranges and would likely remain geographically stable. Importantly, enrollment in the parent study was without regard for dental status or oral health. Administrative design considerations included orderly transfer for exam data to machine-readable format by use of optical scan forms designed to register specific oral variables, with security preserved for the primary source records and rapid record retrieval. Additional data collection requiring manual coding was designed to transfer spreadsheets of clinical impressions and diagnoses to computer retrieval protocols. Provisions for recording of exceptional circumstances, i.e., salient oral pathology, were recognized and the optical scan forms modified to index and retrieve such cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Examiner reliability in dental radiography

In long-term investigations involving a large number of study participants, it is frequently necessary to employ the use of multiple examiners who must exhibit high levels of inter- and intra-examiner reliability in order to minimize examiner bias, which can distort scientific findings. This report on the calibration of four examiners in a large project investigating the efficacy of dental radiography shows high levels of examiner reliability using various statistical measures of agreement. Levels of intra-examiner agreement using Cohen's Kappa index were 0.75 and higher at baseline, and remained at approximately the same level (0.80) throughout the 24-month period of the study. The Kappa index of inter-examiner agreement among the six pairings of the four examiners ranged from 0.68 to 0.80 for caries and 0.72 and 0.83 for periodontal disease. Values of four statistical measures of agreement (proportional agreement, Kendall's rank correlation, Cohen's Kappa index, and Cohen's weighted Kappa index) were determined to show the importance of using measures, such as the Kappa index, which take chance agreement into account.

Percent agreement, Pearson's correlation, and kappa as measures of inter-examiner reliability

Percent agreement and Pearson's correlation coefficient are frequently used to represent inter-examiner reliability, but these measures can be misleading. The use of percent agreement to measure inter-examiner agreement should be discouraged, because it does not take into account the agreement due solely to chance. Caution must be used in the interpretation of Pearson's correlation, because it is unaffected by the presence of any systematic biases. Analyses of data from a reliability study show that even though percent agreement and kappa were consistently high among three examiners, the reliability measured by Pearson's correlation was inconsistent. This study shows that correlation and kappa can be used together to uncover non-random examiner error.