Evaluation of the effect of interexaminer reliability in clinical trials of dental caries prevention

Data from a 3-yr clinical trial were used to assess reliability of two dentists who, without standardizing techniques, independently examined 286 continuous participants. Only 13.1 of 128 tooth surfaces (third molars excluded) showed a change in caries status during the trial by one or both examiners' findings. Although there was poor agreement between the examiners (46.5%) on these changes, they agreed very closely on measuring the cariostatic effects in the various treatment groups because the disagreements were random and were similar among groups.     

颌骨牙源性囊肿袋形术/减压术引流装置的设计与临床应用

 颌骨牙源性囊肿是一组来源于与牙发生相关组织的病变，上皮衬里的囊腔包含液体或半流体。由于囊腔内的压力、骨吸收因子释放及上皮增生引起囊肿不断增大，导致颌骨膨隆、牙松动移位，面部畸形及咬合功能障碍。牙源性囊肿的袋形术/减压术是一种简单易行而有效的保守性治疗方法。成功的治疗需要术后采用不同引流装置保持囊肿引流。较大的囊肿常在术后配戴囊肿塞或阻塞器，而较小的病变则通过减压管保守引流。大多数病例是在袋形术/减压术后囊肿缩小时二期行囊肿刮除术，可减少邻近结构的损伤或手术并发症，仅少数病例中袋形术作为惟一的治疗方式。文章简要介绍了袋形术/减压术的相关治疗机制以及多种引流装置的设计与临床应用。     

A regression model analysis of longitudinal dental caries data

Longitudinal data on caries experience were derived from the reexamination and interview of a cohort of 306 subjects with an average follow-up period of 33 years after the baseline examination. Analysis of the data was accomplished by the use of contingency tables utilizing enumeration statistics compared with a multiple regression analysis. The analyses indicated a strong association of caries experience at one point in time with the caries experience of that same person earlier in life. The regression model approach offers adjustment of any given independent variable for the effect of all other independent variables, providing a powerful means of bias reduction. The model is also useful in separating out the specific effect of an independent variable over and above the contribution of other variables. The model used explained 35% of the variability in the DMFS scores recorded. Similar models could be useful adjuncts in the analyses of dental epidemiologic data.     

"The rise and fall" of dental caries: some global aspects of dental caries epidemiology

Abstract The purpose of this paper was to review some global aspects of dental caries epidemiology. Existing data show that caries activity has increased, often rapidly, in developing countries in recent years while marked reductions have occurred in some industrialized countries during the last 10-15 years. Changes in the prevalence of a multifactorial disease like dental caries arc difficult to explain but the obvious ones seem to coincide either with increased intake of refined sugar-containing products or with increased use of fluorides. Furthermore it would appear that restorative treatment alone has little impact on caries activity when viewed in a life long perspective. Experience, the existing geographic distribution of oral health problems and resources to cope with them suggest an urgent need for co-operation in dental eduction and research between developing and industrialized countries to develop acceptable cost-elective preventive programs in countries where caries activity is high or increasing rapidly.     

An approach to objective assessment of caries prophylactic measures in a dental health program

ABSTRACT In a retrospective survey the mean number of intact proximal surfaces on the first molars of 13-year-old children was found to increase from 2.6 to 4.8 following 7 years of a preventive program with fortnightly fluoride mouthrinsings (0.2% NaF). This improvement was significant and corresponded to a reduction of the totally filled surfaces from 30.0 to 16.6. Caries on the proximal surfaces on the first molars was assessed from bite-wing radiographs. Judged from interexaminer comparisons, the number of filled surfaces was a reliable parameter of the caries prevalence ill 13-year-old children. In a group of 54 children aged 13 who participated in the preventive program, the caries experience on the proximal surfaces of the first molars was significantly associated with the total DMFS.     

Declining dental caries in Jerusalem schoolchildren

Abstract There has been an increase of dental caries in Israel during the last decade (1970–80), while most developed industrialized countries reported a decline in dental caries since 1970. A survey carried out on 267 first graders (6 yr old) by the same investigator and with the same methods as in the previous survey (1977), showed a significant decrease in prevalence of dental caries in 1985 as follows: 78% affected children with a caries score of 4.9 compared to 86.2% with a caries score of 5.2 in 1977     

Increment of dental caries among Finnish dental students during a period of 2 years

The purpose of the study was to estimate the increment of dental caries among dental students in Helsinki, who acquired good knowledge of caries prevention during their studies. The group (59 students) was examined twice with an interval of 20.2 +/- 4.1 months. Clinical findings, augmented with bitewing radiographs and an orthopantomogram, were recorded separately for each tooth surface, and individual DMFS and DS index scores were computed. In addition, the students were interviewed with regard to oral hygiene, topical fluoride application, and dietary habits. The mean DMFS and DS index scores at the first examination were 45.0 and 9.1, respectively. At the second examination, DMFS was 46.4 and the number of new decayed surfaces per student 0.54/year. Both the latter values indicated that caries progression was slow. The increment of dental caries among the dental students was much smaller than that observed earlier among other groups of university students in Finland. Further evidence that caries progression among the dental students was slow was provided by the finding that of the 318 incipient caries lesions recorded at the first examination, no more than 11 had developed into clinical caries by 20 months.     

Validation of a simple approach to caries risk assessment

OBJECTIVE: This study examined the predictive validity of a simple subjective method promoted to dentists for assessing their patients' caries risk. METHODS: Data from two large group practices that have used guideline-assisted caries risk assessment (CRA) for several years were analyzed retrospectively to determine the receipt of caries-related treatment following a CRA. Patient age and receipt of caries preventive treatment subsequent to the CRA were control variables in logistic regressions to determine the likelihood of caries-related treatment for low, moderate, and high risk groups. RESULTS: Among 45,693 individuals in the two plans, those categorized as being at high caries risk were approximately four times as likely to receive any caries-related treatment as those categorized as being at low caries risk. Those categorized as at moderate risk were approximately twice as likely to receive any treatment. In addition, for those at elevated risk who required any treatment, the number of teeth requiring treatment was larger. CONCLUSION: The results of this study provide the first large-scale, generalizable evidence for the validity of dentists' subjective assessment of caries risk.     

Effect of different diagnostic thresholds on dental caries calibration

OBJECTIVES: (a) To analyze the intra- and inter-examiner reproducibility (reliability) of a calibration trial, at different diagnostic thresholds of dental caries; (b) to verify the accuracy (benchmark validity) though sensitivity (S), specificity (SP), positive (PPV) and negative predictive (NPV) values. PARTICIPANTS: A group of dental examiners (n=11), who had previous experience in epidemiological surveys and six to seven-year-old children. Children were selected according to the dmft and dental caries activity. METHODS: Theoretical and clinical training and calibration exercises were arranged for a total of 28 hours. WHO criteria including the active initial lesions (IL) were used. MAIN OUTCOME MEASURES: WHO and WHO+IL diagnostic thresholds according to tooth and dental surface. RESULTS: Excellent mean results of intra and inter-examiner Kappa values were found for both diagnostic thresholds, according to tooth and surface, during the calibration phase. The most relevant errors were related to IL diagnosis and to the first permanent molars. When assessed against a benchmark examiner, moderate to high validity values were observed (0.71-1.00), with some loss mainly for sensitivity and positive predictive value, when including IL. CONCLUSION: It was possible and feasible to use the proposed methodology of this study in epidemiological surveys, even with the inclusion of IL. However, further examiner calibration studies are still needed in order to improve and establish a methodology of calibration with this new diagnostic threshold.     

A combined approach to preventing dental caries in schoolchildren: caries reductions after 3 years

A combination of preventive methods have been used to reduce dental caries in children residing in a fluoridated area of Southeastern Michigan. These children had very low restorative treatment levels. The methods used include dental health education, prophylaxis, pit and fissure sealants, topical application of fluoride and restorative care. Prophylaxis, sealant and fluoride procedures were repeated every 6 months. Sealant was applied to all caries-free posterior teeth in the mouth. Three-year results show reduction of occlusal caries increments of nearly 73% for both 1st and 6th school grades. Although at baseline examination there was no statistically significant difference between the two groups in mean DMF teeth and surface scores, the difference in mean increments at the end of 3 years was statistically significant (P less than 0.01). Percent reductions in caries increment for permanent first molars in 1st graders were 65.6 for DMF teeth and 66.7 for DMF surfaces. Corresponding figures for permanent teeth among 6th graders were 71% and 58.3%.     

Epidemiologic characteristics of dental caries: relation of DMFS to DMFT

Abstract The relationship between the age-specific mean number of DMF teeth and the age-specific mean number of DMF surfaces in the population has been studied using the original data of Knutson and epidemic/logic data from five Finnish materials, including data of 4718 subjects examined. Two models of regression between the variables were evaluated statistically by making a comparison between a linear and a curvilinear model of regression. For Knutson 's original data, both models were suitable, apart from one data set with a relatively high caries prevalence, for which the association between the variables could be better expressed by the linear model. Concerning the recent Finnish materials, the difference in accuracy between the models seemed to be related to the range of the measurements; the larger the range of the measured caries prevalences, including low and high prevalence rates, the more preponderant the curvilinear model. For very low caries populations as well, the curvilinear model, a correction exponential curve, seemed to fit caries data somewhat better than the straight line.     

东北地区老年人群患龋状况的抽样调查报告

目的了解东北地区老年人群的患龋状况,为制定防治方案提供基线资料。方法采用多阶段分层等容量随机抽样的方法,按照世界卫生组织《口腔健康调查基本方法》（第4版）的原则,对东北三省2 364名65～74岁老年人的冠龋和根龋情况进行检查,应用SPSS 12.0统计软件对三省患龋情况进行分析。结果1）东北地区65～74岁老年人的患龋率为67.5%,龋均为2.68,因龋充填牙构成比为10.82%;2）东北地区65～74岁老年人的冠龋患龋率为66.4%,龋均为2.55,因龋充填牙构成比为11.37%;3）东北地区65～74岁老年人的根龋患龋率为48.4%,龋均为1.64,因龋充填牙构成比为1.8%。结论东北三省老年人群患龋率高,治疗率低。开展针对老年人的社区口腔卫生服务是提高老年人口腔健康状况的前提。     

Methods of measuring the reliability of caries prevalence and incremental data

abstract The purpose of undertaking repeat examinations in oral epidemiology has been discussed. Since many of the published methods of demonstrating repeatability do not allow the influence of error to be quantified, the value of estimating reliability was investigated. This is based on the assumption that the coefficient of reliability is the ratio of true to total variance, where total variance is the sum of true and error variance. It was suggested that the reliability coefficient together with error variance should be used to express repeatability in oral epidemiology since reliability is closely related to the efficiency of the study and allows the relative importance of error to be assessed. Five methods for determining the reliability of dental caries data have been investigated and compared; all but one required the reexamination of subjects. The fifth method, although not requiring a reexamination, was considered unsuitable for use in caries studies. The two methods recommended for use in prevalence surveys were simple to use and provided data from which the reliability of incremental scores might be calculated.     

Epidemiology of dental caries in 5-year-old children in Israel

The objective of this study was to assess the prevalence of dental caries in the earliest age at which children were organized as a group in the national education system and to find possible associations with variables that may help to identify "groups at risk" in this population. A total of 965 children, 5 years old, were examined. They were selected by a method to form a representative sample of all West Jerusalem compulsory kindergarten classes in 1971. Caries, gingivitis and oral hygiene were assessed and demogrphic data were collected. It was found that 84% of the children were affected with mean dif value of 4.7 (+/- 3.6). Association was found between caries and social class. The high morbidity suggests that organized services should be planned for this age group. Since the resources are limited, efforts should be directed mainly towards "groups at risk".     

Effect of different diagnostic thresholds on dental caries calibration - a 12 month evaluation

OBJECTIVE: To analyze the reproducibility of a calibration trial, at different diagnostic thresholds of dental caries, in a 12-month evaluation. METHODS: A group of dental examiners (n = 11), who had previous experience in epidemiological surveys, participated in the study. An initial training phase (theoretical and clinical) and five calibration exercises (baseline, 3, 6, 9 and 12 months) were arranged. World Health Organization (WHO) criteria, including the active initial lesions (IL) were used. Six- to 7-year-old children took part in the study. They were selected according to past history and dental caries activity. The data were analyzed at WHO and WHO + IL diagnostic thresholds in accordance with tooth and dental surfaces. RESULTS: Excellent mean intra- and inter-examiner Kappa values were obtained for both diagnostic thresholds, in accordance with tooth and surface, during the calibration phases. However, the most relevant errors were related to the decayed component and to IL diagnosis. CONCLUSION: It was possible to use the methodology proposed in this study in epidemiological surveys when examining the mixed dentition, although new strategies to improve training in IL diagnosis and calibration are necessary.     

Diagnosing dental caries in populations with different levels of dental fluorosis

The aim of this study was to assess the reliability of the Nyvad visual–tactile caries-diagnostic criteria when used among children who have been lifelong residents in areas with 'optimal' or low concentrations of fluoride in the drinking water. In each of two areas with drinking water fluoride concentrations of 0.3 and 1.1 ppm (0.3 and 1.1 mg/l) fluoride, respectively, 150 children were clinically examined twice, 2 wk apart, for dental fluorosis, using the Thylstrup-Fejerskov index (TF index), and for dental caries using the Nyvad visual–tactile caries criteria. The prevalence of dental fluorosis was 45% in the 1.1 ppm fluoride area and 21% in the 0.3 ppm fluoride area. When the results of the duplicate caries recordings were compared at the surface level, only minute differences were observed in the percentage agreement (91.7 and 90.7%, respectively) and in the kappa values (0.73 and 0.72, respectively). When individual DFS counts were compared across examinations using Bland–Altman plots and estimation of prediction intervals for the differences, we observed a greater variability of the differences between recordings among children from the low-fluoride area. Contrary to our expectations, a pronounced dental fluorosis background did not reduce the reliability of the caries recordings, which appeared to be slightly less reliable at very low levels of dental fluorosis.     

Assessment of different methods for diagnosing dental caries in epidemiological surveys

AIMS: The aims of the study were: (i) to assess different clinical diagnostic methods of dental caries during epidemiological surveys; (ii) to determine which combinations of methods and diagnostic adjuncts show the best performances in epidemiological surveys when compared with examinations performed in a traditional dental setting (standard); (iii) to evaluate the influence of including noncavitated (NC) lesions in dental caries estimation. METHODS: Forty 12-year-old children were divided into low and moderate caries prevalence groups. The individuals were submitted to 12 epidemiological examinations (in an outdoor setting), which combined three methods (blade, mirror and mirror + CPI (Community Periodontal Index) dental probe) with or without diagnostic adjuncts (previous dental brushing and dental drying). The last examination was performed in a traditional dental setting (standard examination). The unit of measure was the DMFS (decayed, missing and filled surfaces) index according to WHO criteria. The variance analysis, Dunnet's and Tukey's tests were applied. RESULTS: For the DMFS analysis, the visual/tactile method, with or without diagnostic adjuncts, was the best method for both groups, presenting a performance higher than 90% when compared with the standard examination, except for the examinations without previous dental brushing for the low caries prevalence group. Previous dental brushing was more relevant than dental drying (P = 0.0054). All of the epidemiological examinations underestimated the NC diagnosis even with the association of diagnostic adjuncts when compared with the standard examination. CONCLUSION: The visual-tactile (for both groups) and the visual (mirror) methods plus dental brushing (for the moderate group) are appropriate for diagnosing cavitated lesions, but not NC lesions.     

Dental caries experience and prevalence of children afraid of dental treatment

The aim of this study was to examine the clinical outcome with regard to dental caries of high self reported dental anxiety in a group of Scottish secondary schoolchildren. 1103 children participated in the study, mean age 14 yr (sd 0.35 yr), and the prevalence of high dental anxiety was 7.1% (95% CI = 5.6%, 8.6%). When these children were compared with their contemporaries their DMFT and all its components were higher but only the mean MT reached statistical significance after adjusting for gender and social class. Children with a high dental anxiety were 62% more likely to have at least 1 missing tooth due to caries. In addition this group when compared to the rest of the study population, had a significantly lower mean number of teeth fissure sealed and a lower proportion of children with sealants. No similar trend was obvious for children who had a high general fear. The dentally anxious more accurately perceived their treatment need and were more likely to defer, cancel or not turn up for dental appointments.