Errors in diagnosis of approximal caries on bitewing radiographs

ABSTRACT The number of overlapped and unreadable surfaces occurring on bitewing radiographs of 1,417 children participating in a clinical trial was recorded. Of erupted surfaces, only 73.3 % were completely visible to both participating examiners. Interexaminer and intraexaminer reproducibility ratios were calculated according to the F.D.I, recommendations. The ratios obtained in the present study ranged from 0.06 to 0.36. Almost 57 % of approximal cavities were diagnosed on radiographic examination only: 21 % were diagnosed clinically, but were not apparent on the radiographs.     

Value of bitewing radiographs in detection of occlusal caries

A system of diagnosing occlusal caries from bitewing radiographs was developed in an attempt to overcome the problems of clinical diagnosis found in other studies. Standardised bitewing radiographs for 1172 Berkshire schoolchildren aged 11-13 years who were participating in a toothpaste trial, were assessed for occlusal caries under uniform magnification and illumination. The radiographic scores were then compared with the clinical records for these subjects. The radiographic technique proved to be acceptably reproducible at 82.6%. However, only 33.2% of the lesions present were detected on the radiographs. It is concluded that bitewing radiographs for the detection of occlusal caries are of little value in epidemiological studies.     

Monitoring of caries progression in permanent and primary posterior approximal enamel by bitewing radiography A review

The work which has monitored caries progression in posterior approximal enamel surfaces by reference to the size of radiolucency seen on bitewing radiographs is reviewed. There are wide variations in the degree of standardisation achieved, in the composition of the study groups and in the duration of the studies. There is a paucity of information relating to adults, the elderly, groups with low caries prevalence, and fluoridated communities. The results indicate that for the majority approximal caries progresses slowly, and large numbers of lesions remain unchanged for long periods. The available results are compared using the mathematical model of a negative exponential. The 'mean' time during which a lesion remains radiographically confined to the enamel is of the order of 3-4 yr, although in caries active individuals much shorter times are reported. Some clinical implications are suggested and the need for further research using comparable methods is stressed.     

Reproducibility and overlapping of bitewing radiographs: comparison of Eggen-bite with Kwik-bite

In the present study the reproducibility of horizontal dimensions and of overlappings of two filmholder techniques with aiming devices (Eggen-bite and Kwik-bite) and additionally the number of overlappings on the resulting bitewing radiographs were compared. The overlapping reproducibility was significantly higher with Kwik-bite. The microdensitometric reproducibility demonstrated the same tendency, but the result was not significant. Bitewings carried out by an oral radiologist demonstrated fewer overlappings with Eggen-bite than with Kwik-bite, while bitewings carried out by inexperienced students revealed no difference between the methods. Both reproducibility and number of overlappings should be taken into consideration when bitewing filmholder techniques are used in epidemiological and longitudinal studies.     

Frequency and distribution of proximal overlappings on posterior bitewing radiographs

Abstract 4374 proximal surfaces on 791 posterior bitewing radiographs were classified according to overlappings. Six categories were used: 1) no overlapping, 2) blurred contact areas, 3) less than half of the enamel overlapped, 4) more than half of the enamel overlapped, 5) dentin overlapped, and 6) unclassifiable overlappings. Filled surfaces and surfaces not in contact were excluded. Only 19% of the surfaces did not have overlappings. 65 % exhibited mild overlappings (categories 2 and 3), and 16 % severe overlappings (categories 4, 5 and 6). The frequencies of no overlappings varied from 7% to 40% for single tooth surfaces. The relationship between distribution of overlappings and tooth surfaces was statistically significant at the 0.05% level. Principles of excluding overlapping surfaces have been inconsistent in previous epidemiologic studies and clinical trials. The use of exact criteria for exclusion is recommended.     

Factors influencing the likelihood of successful decisions to treat dentin caries from bitewing radiographs

The purpose of this study was to describe the role played by the ability to estimate caries depth in successfully deciding to treat dentin caries when making use of bitewing radiographs as a diagnostic test. A 10% random sample (n = 444) of Dutch dental practitioners was sent a two-wave questionnaire concerning radiographic caries diagnosis and restorative treatment decision making. The second wave consisted of simulated bitewing radiographs of 105 tooth surfaces with and without dentin caries according to two measuring standards: (a) a micro-radiographic "gold" standard and (b) a norm of expert observers. The dentists were asked to diagnose caries at 4 depths of penetration using a 5-point certainty scoring system to measure diagnostic ability; and to make a treatment decision for each surface. The overall response was 61% (273). A regression analysis was carried out using the chance per dentist of correctly deciding to treat dentin caries as the dependent variable. The degree of agreement with the experts' diagnosis of radiographic caries depth was used to create variables measuring diagnostic ability. Five significant (P less than 0.05) variables explained 60% (R2 = 0.60) of the variation in decision making. The best diagnostic ability variable explained 47% of the variation while the treatment criterion reportedly used explained 3%. We conclude that the ability of practitioners to interpret radiographs plays a major role in treatment decision making and that their reported treatment decision making criteria should not be taken at face value.     

Approximal caries and frequency of bitewing examinations in Swedish children and adolescents

The aim of this study was to assess the number of, and time intervals between, bitewing examinations performed on a group of Swedish patients between 3 up to and including 18 yr of age and to relate them to the accumulated posterior approximal caries experience of the patients as found in the last bitewing examination before age 19. The patients showed a marked variability in approximal caries experience. 25% accounted for about 1% of the total number of carious lesions and restorations accumulated up to age 19 while 25% accounted for 60%. From age 9 up to age 18 more than 75% of the patients were subjected to at least one bitewing examination annually. Between 10 and 15 yr of age more than 90% received annual radiographic examinations. Mean number of bitewing examinations was 10.4 and the average time interval between bitewing examinations was 11.5 months. 11% of the variation in the number of bitewing examinations and 8% of the variation in average time intervals between bitewing examinations could be explained by the number of lesions and restorations in the approximal surfaces of the patients accumulated up to age 19.     

Accuracy at radiography and probing for the diagnosis of proximal caries

In 63 teenagers the proximal surfaces of premolars to be extracted for orthodontic reasons and the adjacent surfaces of neighboring teeth, 598 surfaces in all, were examined radiographically and by probing. Direct inspection after extraction revealed that 51% of the surfaces had incipient carious lesions and 5% lesions with cavities. Of the surfaces with cavities 82.1% were correctly diagnosed radiographically if any radiolucency, regardless of its extent, was used as a diagnostic criterion. However, this yielded a false positive rate of 19.6%. If only radioluccncies extending at least into the inner third of the enamel were called positive the true positive rate was 36.7% and the associated false positive rate 1.6%. At a 5% cavity frequency the predictive positive values were 17% and 53%, respectively. Probing yielded a true positive rate of about 29% and a false positive rate of 1.1% with a predictive positive value of 50-57%. All radiolucencies extending into the dentin were associated with cavities. When the most liberal radiographic criterion was used 37.5% of all carious lesions, whether associated with a cavity or not, were detected and 3.8% of sound surfaces were falsely called carious. The corresponding predictive positive value at the actual rate of incipient lesions and lesions with cavities was 92.6%.     

Systems for grading approximal carious lesions and overlaps diagnosed from bitewing radiographs Proposals for future standardization

The diagnosis of dental caries from bitewing radiographs has become an important and integral part of many clinical caries trials, particularly in longitudinal studies. Although many seemingly similar systems for grading the degrees of approximal lesions have been used, the diagnostic criteria employed often differ in a number of significant areas. A variety of different conventions have evolved for the treatment of: 1) overlapping surfaces, 2) lesions in the region of the ADJ, 3) subdivision of the radiographic enamel cap and 4) score transitions and caries progression systems. Direct intertrial comparisons may be invalidated by the use of incompatible grading systems. Whilst one rigid grading system will not be suitable for all clinical trials, the use of the appropriate scoring codes and criteria from a standard system may greatly facilitate the comparison and interpretation of results. A comprehensive standard system for the grading and scoring of radiographic diagnoses (compatible with the existing WHO recommendations for the grading of clinically diagnosed lesions) is proposed.     

Value of operating auxiliary personnel for caries diagnosis in dental epidemiology

The ability of a suitably trained operating auxiliary to obtain similar diagnostic results to those of a dentist was tested on 200 11--12 year-old boys and girls selected from a larger sample taking part in a 3-year caries prophylactic clinical trial. A clinical and radiographic examinati-n of all children was performed by both examiners at the beginning of the study and at three subsequent yearly examinations. The reliability of the caries prevalence and incremental data was high for both the dentist and hygienist. Differences between mean caries scores were consistently found between the examiners at the initial lesion level for clinical and radiographic diagnosis. Over the incremental periods of the study neither examiner revealed a significant difference between control and test groups until the end of the 3rd year when both measured a significant difference in mean DMFS at the clinical cavitation level, 26.2% for the dentist and 25.2% for the hygienist.     

Effect of variation in caries diagnosis and degree of caries on treatment decisions by dental teachers using bitewing radiographs

Abstract Nine teachers of clinical dentistry were presented with 12 pairs of duplicated bitewings on four different occasions. At the first two examinations they indicated the presence of caries in need of treatment and at the second two the degree of caries. The diagnostic sessions were repeated to measure reproducibility. A norm for the validity of degree of enamel caries and for the estimation of specificity and sensitivity of the diagnostic categories was applied. The teachers saw on average less caries and less deep caries than the norm. Variability by the teachers was especially large between examinations for enamel lesion categories. There was a mean of 69% agreement by the teachers with their own treatment indication criteria. Over recording of treatment need (mean 19%, SD 20%) and under recording (mean 36%, SD 17%) occurred at the same viewing periods. Using Cohen's kappa, it was found that despite their variation and inaccuracy this group of teachers should select caries in dentin as the teaching criterion for treatment need. It is suggested that the sensitivity and specificity with which dental practitioners can use a criterion should be taken into account firstly when selecting it, and secondly when choosing the frequency of radiographic screening.     

A method for obtaining periodic identical bitewing radiographs

ABSTRACT – A method for obtaining periodic identical bitewing radiographs has been developed using impression.s of the occlusal surface of molars and premolars. Two positioning devices, one fixed to the film holder, and the other mounted on the X-ray tube, were used in order to obtain periodic identical radiographs. Because no fixed connection between the film holder and the X-ray tube is employed, it is possible to obtain several radiographs with the same film holder. Using a stereoautograph, the error of the method was found to be very low and probably without clinical importance. The method may be valuable in clinical trials where no changes in the occlusal anatomy are taking place over time, or where it is possible to correct minor changes due to tbe insertion of fillings.     

Dutch dentists'' decisions to take bitewing radiographs

A postal questionnaire was sent to a 10% (n = 444) national random sample of Dutch dental practitioners. The response was 77% (n = 344). The practitioners prescribed bitewings on average for 57% of "new" 25-yr-old patients. Five significant (P less than 0.05) variables explained 24% of the variation in bitewing prescribing for these "new" patients. These were, in declining level of importance: the initial dental condition of the patient, the proportion of restorative treatment decisions based solely on radiographs, the level of urbanization of the practice location, the technical level of the practice equipment and the importance attached by dentists to the diagnostic use of dental floss for interproximal caries diagnosis. The low power of the regression model in explaining variation in the decision to take bitewings indicates an idiosyncratic use of bitewing radiographs for caries diagnosis. A weak tendency to adopt different diagnostic sets of procedures was demonstrated.     

A comparative radiographic investigation of caries prevalence in Danish schoolchildren

In order to assess the prevalence of untreated caries in two groups of Danish 7th grade (13- to 14-year-old) school children in a blind study, a radiographic investigation was carried out. Only half of the children (394) had received regular school dental care during their years of attendance of primary school; the other children (368) had not. A bitewing radiograph of the right side of the mouth of each child was taken, employing a standardized technique. The radiographs were read without the examiner knowing the group identity of the radiographs. The criteria for discarding poor radiographs, teeth, and tooth surfaces are described. Some of the radiographic results are compared with the clinical caries score of the same group. Most of the radiographs without untreated caries were found among those of the children who received school dental service. Uncertainty of method in connection with radiographic investigation is discussed.     

Accuracy of computer-automated caries detection in digital radiographs compared with human observers

The aim of this study was to compare diagnostic accuracy of a caries detection program with that of human observers. A total of 190 extracted teeth were radiographed with two Trophy RVG (RadioVisioGraphy) digital sensor systems. Four observers scored the approximal surfaces in all images on a disease severity scale. Each observer thereafter used the Logicon Caries Detector (LCD) program to analyse the surfaces in the digital images and recorded their outcome. To determine the true absence or presence of caries, histological validation was used. Sensitivities, specificities, positive and negative predictive values were calculated and differences between the diagnostic methods tested. Specificities for the outcome with the LCD were significantly lower for three observers than when they themselves assessed the RVG images and, correspondingly, the positive predictive values were lower for the LCD outcome for three of the observers. Sensitivity was also lower for two observers on the diagnostic threshold caries in dentine. It was concluded that the automated caries detection program is less accurate than human observers in detecting approximal caries lesions.     

Looking for caries…? Teachers evaluate a program to improve caries diagnosis from radiographs

We developed a computer-assisted learning (CAL) program to improve student caries diagnosis from bitewing radiographs. In order to decide on its appropriateness, dental teachers independently evaluated the program before it was introduced. Our objective was to describe an evaluation by the teachers of the CAL diagnostic module and to compare the diagnostic performance with the evaluation score of the program. Key dental teachers involved in teaching clinical caries diagnosis and epidemiology (n = 22) viewed the CAL program. They evaluated aspects of the program by scoring 10 criteria on a visual analogue scale. Measures of the teachers' initial diagnostic accuracy assessed during use of the program were: sensitivity and specificity for the presence of dentine caries. Using Pearson's correlation coefficients, these measures of the teachers' diagnostic accuracy were compared separately with their evaluation score of one aspect of the program: the overall functionality of the program for a 2nd-year dental student. The teachers' mean sensitivity for dentine caries diagnosis was 76.5% (median 77.8%; SD 15.4%) and the mean specificity was 93.7% (median 94.2%; SD 3.9%). The teachers gave the program a mean overall functionality score of 68% (median 75.1%; SD 21%). Dentists with a lower sensitivity (P = 0.065) for dentine caries tended to give the CAL program a higher overall functionality score than the other teachers. The CAL program was valued as generally useful. It tended to be more highly valued by the dentists with initially lower scores for diagnostic accuracy.     

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.     

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".