[The effect of the risk of a complaint on treatment decision making. An explorative investigation in fourth-year dental students]. / Het effect van de klachtkans op een behandelbeslissing. Een exploratief onderzoek onder vierdejaarsstudenten tandheelkunde.

The perception of the seriousness of a false-negative or false-positive diagnosis could influence treatment decision making for carious lesions. In order to investigate this hypothesis, the perceived risk of a complaint at a disciplinary tribunal was used as an indicator of the seriousness of the consequences of treatment decision errors. Using a computer programme for caries diagnosis on radiographs and by means of a questionnaire, was investigated in a group of fourth-year dental students whether their accuracy of treatment decision making for carious lesions was dependent on the perception of the risk of a complaint at a disciplinary tribunal. The perception of the likelihood of complaints does not seem to play a significant role in the accuracy of decision making. However, the students demonstrated unrealistical high risk perceptions of a complaint at a disciplinary tribunal following a treatment decision making error by a false diagnosis of a carious lesion on a bitewing radiograph.

Evidence-based diagnosis and clinical decision making.

The application of evidence-based dentistry to diagnosis should result in a reduction of errors in decision making. The frequency of errors is dependent not only on the accuracy of a diagnostic test for pathology, but also on the prior chance of disease being present. If this chance is low and below a certain threshold, then, for example, applying a diagnostic test can result in more decision errors and therefore inappropriate treatment than omitting to use the test. In deciding on the usefulness of a diagnostic test an additional factor to take into account is the relative value of the possible health states resulting from diagnosis and subsequent therapy. These can be determined by eliciting from the patient the numerical values of the possible dental health conditions using a visual analogue scale technique. Clinical decision analysis can then be carried out to calculate the most appropriate diagnostic strategy for the patient. Clinical decision analysis is starting to influence the development of guidelines for the diagnostic use of radiographs although its application in dentistry needs further refinement and development.

An evaluation by teachers of a decision aid for viewing bitewing radiographs.

OBJECTIVES: To evaluate a new decision aid to improve restorative treatment decision making for proximal caries from bitewing radiographs. METHODS: Dental teachers involved in patient treatment and clinical caries diagnosis (n = 31) viewed a computerized decision aid. Whilst using the aid, measures of the teachers' diagnostic and treatment accuracy, and also their decision-making knowledge and values were recorded. After completing the aid, they evaluated its performance on ten aspects using visual analogue scales. We carried out two linear regression analyses, using "Overall usefulness" of the aid as the dependent variable. The independent variables were (1) nine decision-making variables and (2) the nine other aspects of aid performance. RESULTS: The teachers gave the program a mean overall usefulness score of 70% (median 73%, standard deviation (SD) 15%). Information presentation scored lowest (mean 58.9 %, median 64.5%, SD 19%) and aesthetic appearance of the aid scored highest (mean 77.4%, median 80.5%, SD 11.5%). The teachers' diagnostic and treatment decision-making acumen was not related to the score for overall usefulness (P > 0.14). Dentists with a lower subjective estimate of the probability of disease or a higher subjective estimate of 10-year restoration survival valued the aid more highly (P < or = 0.001). CONCLUSIONS: The basic decision-making variables from which the aid provides individual feedback and advice may need additional improvement in presentation. Despite shortcomings and irrespective of the users' diagnostic ability, the aid was valued as generally useful.

[Evidence-based diagnosis and clinical decision making]. / Evidence-based diagnostiek en klinische besluitvorming.

The application of evidence-based dentistry to diagnosis should result in a reduction in errors in decision making. The frequency of errors is dependent not only on the accuracy of a diagnostic test for pathology but also on the prior chance of disease being present. If this chance is low and below a certain threshold then, for example, applying a diagnostic test can result in more decision errors and therefore inappropriate treatment than omitting to use the test. In deciding on the usefulness of a diagnostic test an additional factor to take into account is the relative value of the possible health states resulting from diagnosis and subsequent therapy. These can be determined by eliciting from the patient the numerical values of the appropriate dental health conditions using a visual analogue scale technique. Although clinical decision analysis is starting to influence the development of guidelines for the diagnostic use of radiographs, its application in dentistry needs further refinement and development.

[Digital radiography in young children. Considerations based on experiences in practice]. / Digitale radiografie bij jonge kinderen. Afweging op basis van praktijkervaringen.

In dentistry, digital radiology techniques, such as a charge-coupled device and a storage phosphor plate, are gaining popularity. It was the objective of this study to assess the importance of the advantages and disadvantages of digital radiology techniques for bitewing radiography in young children, when compared to conventional film. A group of dentists received a questionnaire regarding their experiences with digital radiology techniques or conventional films among young children. Using the Simple Multi-Attributive Rating Technique (SMART) a final weighted score was calculated for the charge-coupled device, the phosphor plate, and conventional film. The scores were 7.40, 7.38, and 6.98 respectively. The differences were not statistically significant (p > 0.47). It could be concluded that, on the basis of experiences in practice, there are no statistically significant preferences for the use of digital radioogy techniques for bitewing radiography in young children.

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.

Randomized controlled trial of a computer-assisted learning program to improve caries detection from bitewing radiographs.

OBJECTIVES: To investigate whether using a computer-assisted learning (CAL) calibration program improves the accuracy of dental students in caries detection from bitewing radiographs. METHODS: Dental students were assigned to an experimental (n=33) and control (n=34) group using a randomized block design. The experimental group used the CAL program with feedback to calibrate themselves against experts in radiographic caries detection and a histological gold standard of the actual clinical condition. Feedback was provided visually of the actual tooth surface condition and in the form of graphics showing diagnostic accuracy performance measures. Performance was tested before the program (for the control group) and after the program (for the experimental group) by assessing surfaces (n=56) from a new independent digital test set of evaluation radiographs for the presence, histologically, of dentine caries (n=23). The summary receiver operating characteristic (SROC) method for summarizing true positive ratio (TPR) (sensitivity) and false positive ratio (FPR) (1-specificity) was used to analyse the dichotomous data. Differences between the control and experimental groups were tested for (a) the area under the SROC curve (A(z)) and (b) the TPR, FPR and diagnostic odds ratio (DOR) using the Mann-Whitney test (P<0.05). RESULTS: The mean TPR for dentine caries detection was 76.3% (SD 13.0%) for the experimental group and 66.9% (SD 14.8%) for the control group (P=0.005). Mean FPRs were similar (experimental 28.1% and control 28.7%; P>0.5). The area under the SROC curve A(z) was 0.832 for the experimental group and 0.773 for the control group (P=0.002). The mean DOR for dentine caries in the experimental group (12.4) was better than that in the control group (8.8) (P=0.003). CONCLUSIONS: The CAL program does improve diagnostic performance. Improving the cognitive feedback provided by the program should be considered before implementation.

Preferences for oral health states: effect on prescribing periapical radiographs.

OBJECTIVES: To elicit preferences for the outcomes of radiographic endodontic diagnosis and subsequent therapy, and to test for differences in these preferences between three types of dental specialists. METHODS: Using the "standard gamble" method, dentists involved in teaching oral diagnosis (n=26) were asked to rank on a scale of 0.0-1.0 their preferences (utilities) for four treatment outcomes, "composite filling in vital tooth", "composite restoration and root filled", "root filled and post crown" and "extraction and bridge", from a previously analysed diagnostic testing and therapeutic strategy for managing damaged anterior teeth. Respondents consisted of oral radiologists (n=9), specialized treatment planners (n=11) and specialist endodontists (n=6). Using the derived utilities, a decision analysis was subsequently carried out on the expected health value of taking periapical radiographs of patients with otherwise symptomless fractured incisors. RESULTS: "Composite restoration and root filled" (mean utility 0.83, SD 0.15) was the option preferred above that of "root filled and post crown" (mean utility 0.77, SD 0.16) by the entire sample of oral diagnosticians (P=0.007). Radiologists and endodontists had higher utilities for "composite restoration and root filled" than treatment planners. According to the decision analysis, for the preferred option of "composite restoration and root filled", taking a radiograph was the best strategy only when the prevalence of pathology exceeds 10%, 12% and 50% for radiologists, endodontists and treatment planners, respectively. CONCLUSIONS: The expected utility of using radiographs as a diagnostic test varies among groups of dental specialists. We conclude that variation in utilities among dentists could in part explain variation in the diagnostic use of dental radiographs.

Comparing the accuracy of Dutch dentists and dental students in the radiographic diagnosis of dentinal caries.

OBJECTIVES: To compare the diagnostic accuracy of dental students using bitewing radiographs for the diagnosis of dentinal caries with that of general dental practitioners and to establish a bench mark for testing for improvement in diagnostic performance. METHODS: Fourth year dental students (n=259) viewed bitewing radiographs of 105 proximal tooth surfaces. According to a micro-radiography "gold standard" 45 surfaces had dentine caries. The students were asked to diagnose presence and absence of dentine caries from which, under supervision, they calculated their sensitivity (TPR) and false positive rate (FPR). The students binary diagnostic data was compared with the historical data from a random sample of Dutch dentists (n=273). The Summary Receiver Operating Characteristic (SROC) curve method was used to analyse the data. The two groups were tested for differences in (a) diagnostic odds ratio and (b) the area under the SROC curve. RESULTS: The students mean TPR for dentine caries diagnosis was 67.2% (s.d. 11.8%) and the FPR was 8.3% (s.d. 8.4%). The corresponding values for dentists were: TPR 54.0% (s.d. 14.1%) and FPR 3.1% (s.d. 4.5%). Significantly more dentists (85%) than students (72%, P<0.001) had a diagnostic odds ratio > or =21. The area under the SROC curve (Az) was 0.8194 for students and 0.8140 for dentists (P=0.70). CONCLUSIONS: In our study (i) the students had a higher TPR but also a higher FPR than the dental practitioners, (ii) their overall performance (Az) was similar but (iii) for a clinically relevant population the dental practitioners would out-perform the students in diagnostic performance.

Decision analysis in dentistry--the last 30 years.

OBJECTIVES: To review publications in dentistry of decision analyses during the last 30 years. METHODS: A systematic review of the English literature from 1969 to 1998 was performed using specified indexing terms. The number of retrieved articles in dentistry was compared with the number of articles in medicine. The quality of articles in dentistry presenting a decision tree with utilities and a sensitivity analysis was judged using a published peer review process. We report weaknesses of the analyses together with selected applications. RESULTS: Sixty-seven articles were published on decision analysis in dentistry. Whilst the number of articles published in medicine has accelerated there has been a decline in the last four years in dental publications. Only 22 of the articles in dentistry presented a decision analysis with utilities and a sensitivity analysis. CONCLUSIONS: Current weaknesses of the decision analyses reported were: opaque basic assumptions in the description of the analysis, lack of data on patient preferences and of reliable data on the chances of the long-term effects and side effects of intervention together with an absence of sensitivity analyses. The decision analysis approach complements that of "evidence-based health care" by enabling the best empirical evidence to be used in clinical practice. Formal methods such as decision analysis will promote the rational use of existing knowledge. For it to do this the quality of research data will have to improve in dentistry. Furthermore decision analysis is important in education to demonstrate explicitly how decisions might be arrived at and improved.

The role of caries recognition: treatment decisions from bitewing radiographs.

OBJECTIVE: To describe the effect of the ability to estimate caries depth from bitewing radiographs on restorative treatment decisions. METHODS: A 10% random sample of Dutch dental practitioners (n = 444) was sent a two-part questionnaire based on an analytic approach to radiographic caries diagnosis and restorative treatment decision making. In the second part the dentists were asked to diagnose radiographs of 105 tooth surfaces with and without dentine caries and then to make a treatment decision for each surface. A regression analysis was carried out using the negative predictive value (TN/[TN + FN]) of the restorative treatment decision for dentine caries as the dependent variable. RESULTS: The mean negative predictive value for the dentists' proposals from radiographs to leave surfaces untreated was 0.77 (SD 0.05; min. 0.60, max 0.87). Nine significant (P < 0.05) variables explained 65% (R2 = 0.65) of the variation in decision making. One diagnostic ability variable explained 48% of the variation found. CONCLUSIONS: Dentists appear to take the seriousness of errors in restorative decisions into account when deciding on treatment. The ability of dental practitioners to identify and discriminate between lesions in the inner half of the enamel and the outer half of the dentine, however, plays a dominant role in their treatment decision making.

Room for improvement? The accuracy of dental practitioners who diagnose bony pathoses with radiographs.

OBJECTIVES: The impact of any effort aimed at improving diagnostic accuracy by improving clinical decision making in diagnostic radiology will be limited by the ability of the clinician to correctly recognize the presence of abnormalities on radiographs. We carried out a study designed to examine whether dentists are able to correctly identify various kinds of periapical bone lesions visible on intraoral radiographs and diagnose their pathologic nature. STUDY DESIGN: General dental practitioners (n = 98) assessed 32 radiographs that showed either normal bone (10) or one abnormality (22) in the periapical bone. The "gold standard" for pathosis was histopathologic analysis. The dentists were asked to judge for the presence of an abnormality and to decide whether an active pathologic process was present. RESULTS: On average dentists identified 81% of all visible abnormalities correctly. Subsequently, they diagnosed 59% of all the pathologic cases correctly. Dentists, however, incorrectly identified 55% lesions on radiographs when experts had stated that no abnormality was visible. CONCLUSION: There is room for improvement of diagnostic accuracy of bony pathology.

Use of the Delphi technique to develop standards for quality assessment in diagnostic radiology.

The Delphi technique is a method for obtaining answers to questions that are issues of uncertainty even to experts. The aim of this study was to use the Delphi technique to develop two standards for the assessment of the diagnostic performance of dentists using radiographs. Two Delphi consensus procedures were initiated to determine the presence of visible abnormalities on radiographs and their pathological nature. A panel of expert radiologists was independently selected. This panel reached consensus on the items of both Delphi procedures through a number of rounds of written correspondence. The outcomes of the procedures were compared to a histopathologic norm for the presence of pathology. The group procedure was described as well as tested for dominance on part of any of the individual panellists. It was found that up to 98 per cent agreement occurred among the majority of panellists on items of the procedures. The panellists were significantly better than dentists in the diagnosis of pathology (P < 0.05) and kept improving during the process of consensus formation. In neither of the Delphi procedures was the judgement of any panellist dominant (P > 0.4). It is concluded that, if carefully controlled, the Delphi technique may be used in the development of diagnostic standards in oral radiology.

An approach to the development of decision support for diagnosing pathology from radiographs.

OBJECTIVES: Large inter-observer variation has been reported in oral radiology. Providing observers with a checklist prompting them to focus on specific radiographically visible features with known relevance to the diagnosis has been shown to improve diagnostic accuracy. We intended to investigate whether diagnostic accuracy for bony pathology could be improved by a computerized decision aid. The decision support provided the user with radiographic reference images for the degree of presence of a radiographic feature (such as radiopacity) and structured the use of diagnostic knowledge. METHODS: Twenty-seven general dental practitioners participated in the study. They diagnosed seven radiographic cases of bony pathology using a prototype decision aid and seven other cases unaided. For each radiograph the dentists assessed the degree of presence of five radiographically visible features which had been selected from the literature oral radiology because of their use in describing, radiographically visible bony pathology. The dentists' assessments of degree of feature presence, and their diagnoses, were recorded. Histopathology was used as a diagnostic 'gold standard'. The degree of presence of the features in the radiographic images was also assessed by an independently selected panel of expert oral radiologists in a Delphi consensus procedure. RESULTS: Determination of the degree of presence of three radiographically visible features assessed by the dentists using the prototype decision aid was significantly improved (by up to 12%) compared to the results of their unaided assessments. The diagnostic accuracy of one-third of the dentists was also improved. CONCLUSION: The use of reference images can improve dentists' assessments of the degree of feature presence.

Does radiographic feature recognition contribute to dentists' diagnosis of pathology?

OBJECTIVES: To measure the degree to which dentists can accurately identify radiographic features and use their findings in the diagnosis of three lesions. METHODS: Fourteen radiographic examples were used in this study and five features derived from the literature: border sharpness, border radiopacity, lesion shape, lesion radiopacity and root contact. A 'silver standard' for the presence of the features in the radiographic images of the lesions was established by expert observers; and a diagnostic 'gold standard' based on the histopathology of the lesions was available. Dentists scored each image according to these features and gave their diagnosis. RESULTS: When dentists made different subjective diagnoses for a case, significant differences were found in the extent to which features were reported to be present. The degrees of presence of border sharpness (21%) and border radiopacity (46%) measured using the 'silver standard' were significantly related to the diagnosis of osteosarcoma. CONCLUSIONS: Radiographic information is not used to its full extent and improvement in the recognition of features and the cognitive use of this radiographic information in the diagnostic process could improve diagnostic accuracy.

Diagnostic confidence and the accuracy of treatment decisions for radiopaque periapical lesions.

The periapical radiograph is a tool used in the diagnosis of periapical bone pathology. Radiographic diagnosis might therefore influence endodontic treatment planning and the quality and the cost of dental health care. The hypotheses were tested that (1) the subjective prevalence of a lesion would be associated with the accuracy with which it is diagnosed, (2) 'confident dentists' would be as accurate in their diagnosis as 'doubtful dentists' and (3) the diagnostic confidence of dentists for the diagnosis of periapical pathology would not influence their treatment planning. It was found that the probability of an appropriate treatment decision increased when dentists were relatively confident about a diagnosis. The results showed, furthermore, that the accuracy of diagnostic decisions increased when the dentist's confidence about a particular decision was high. Ways to increase diagnostic accuracy of radiopaque periapical pathology are proposed as a result of this study.

Prescribing endodontic retreatment: towards a theory of dentist behaviour.

The large variations observed in dentists' management of periapical lesions in endodontically treated teeth suggest that disease concepts used in clinical practice should be investigated. In the present study it was hypothesized that dentists regard various periapical conditions as different stages on a health continuum. Variations could then be regarded as the result of the individuals selection of differing cut-off points for prescribing retreatment. The hypothesized decision-making model was tested using dental students in Amsterdam (Holland), Gothenburg (Sweden) and Pavia (Italy). The students were shown six simulated cases among which the quality of root filling seal and presence of post and crown were systematically varied. For each case, management of five periapical conditions was assessed. Five options were offered: no therapy, wait-and-see, nonsurgical retreatment, surgical retreatment, and extraction. For each examiner and case a 'retreatment preference score (RPS)' was established. The investigation showed large interindividual variations in RPS. A statistically significant higher mean RPS was seen among students in Pavia compared with students in Amsterdam and Gothenburg. Among all observers and cases it was found that if retreatment was proposed for a certain size of lesion, retreatment was subsequently selected for all larger lesions. The experiment gave evidence in support of the proposed hypothesis. The data also suggest that the choice of retreatment criterion is affected by values, costs of retreatment and technical quality of the original treatment.

Blind chance? An investigation into the perceived probabilities of phrases used in oral radiology for expressing chance.

The necessity for numerical probabilities in oral radiographic diagnosis is increasing, due to recent developments in computer-aided diagnosis, decision analysis, informed consent and medical litigation. These numerical probabilities are only partly available from current texts on oral radiology, where they are often expressed by ill-defined, semiquantitative phrases. Therefore, in this study 30 phrases expressing the probability of a relationship between a diagnosis and its symptoms were taken from a selected textbook on oral radiology. Seven oral radiologists from the USA and the Netherlands scored each of these probabilistic phrases on a 20-cm visual analogue scale. Low intraradiologist and high interradiologist variation was found. Because the high variation among authors of texts on oral radiology in interpreting probability information could have a negative influence on their ability to transfer unambiguous information to their readers, it is recommended that the use of semiquantitative phrases in oral radiology is restricted to five probability groups.

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.