The use of panoramic radiology in dental practice

Knowledge of Correct Prescription of Radiographs among Dentists in Yazd, Iran

Background and aims

While the use of X-ray is increasing, professional responsibility of dentists entitles them to have sufficient and correct knowledge of using radiographs. The aim of this study was to assess the level of knowledge of correct prescription of radiographs among dentists in Yazd, Iran.

Materials and methods

This was a descriptive cross-sectional study including 134 general dentists and dental specialists. A self-administered questionnaire was used to assess their level of knowledge in various sections pertaining to prescription of radiographs. Their level of knowledge was compared in each section on the basis of gender and educational status.

Results

Participants showed a high level of awareness in prescription of panoramic, periapical radiographs, and computerized tomography, whereas it was moderate in the field of occlusal radiographs, susceptible patients to caries, patients with periodontal diseases, evaluation of growth condition and dental crypts and weak in the fields of bitewing radiographs and insusceptible patients to caries. There was no difference in level of knowledge between genders. The level of knowledge in specialists was higher than general dentists except for using X-ray for susceptible patients to caries where no significant difference was observed.

Conclusion

Specialist dentists were more knowledgeable than general dentists in prescribing radiological examinations.

Extraoral imaging for proximal caries detection: Bitewings vs scanogram

OBJECTIVE

The objective of this study was to compare the diagnostic accuracy of 3 extraoral imaging modalities with an intraoral bitewing radiograph for proximal caries detection.

STUDY DESIGN

Three modalities of Cranex TOME scanograms, x-ray film and DenOptix photostimulable phosphor plates with and without digital enhancement, were compared with Insight intraoral radiographs for proximal caries detection. Nine observers evaluated images of the proximal surfaces of 45 extracted posterior teeth. The presence or absence of caries was scored using a 5-point confidence scale. The ground truth was determined from histological sections. Responses were evaluated by repeated measures analysis of variance (ANOVA) for areas under receiver operating characteristic (ROC) curves (A z ).

RESULTS

Repeated measures ANOVA (at alpha = 0.05) demonstrated significant differences among modalities ( P = .041). Paired t tests with Bonferroni correction demonstrated that Insight was superior to only unenhanced digital scanograms ( P = .003). Mean A z scores (+/-SD) were 0.73 (+/-0.08) for Insight, 0.65 (+/-0.06) for screen/film scanogram, 0.64 (+/-0.04) for unenhanced digital scanogram, and 0.66 (+/-0.07) for enhanced digital scanogram.

CONCLUSIONS

The performances of film-based and enhanced digital scanograms were not statistically different from Insight film for proximal caries detection. Unenhanced digital scanograms exhibited a statistically significant lower diagnostic accuracy than Insight film.

Accuracy of digital panoramic images displayed on monitor, glossy paper, and film for assessment of mandibular third molars

OBJECTIVE

The aim of this study was to compare the accuracy of 3 modalities of digital panoramic radiographs-monitor-displayed images and printed copies on glossy paper and on blue transparent film-for assessment of position and morphology of mandibular third molars.

STUDY DESIGN

164 third molars were recorded with one of 2 digital panoramic systems (Digora and Orthophos Plus) and assessed by 4 observers on 3 radiographic modalities: monitor display, glossy paper, and transparent film. The assessments were compared with surgeons' findings at the time of the operation ("gold standard").

RESULTS

Overall, the observer variation was larger than the variation between methods. A detailed paired analysis revealed some differences between the modalities for some diagnostic categories, but these were few and inconsistent.

CONCLUSION

Printed images from the Kodak 1200 ink-jet printer on glossy paper and blue transparent film may be as accurate as the original monitor-displayed digital panoramic images from the Digora and Orthophos Plus systems for assessment of position and morphology of mandibular third molars.

Determination of dose-area product from panoramic radiography using a pencil ionization chamber: Normalized data for the estimation of patient effective and organ doses

The aims of the present study were (a) to investigate the potential of pencil ionization chamber to be used for the determination of dose-width product (DWP) and dose-area product (DAP) from panoramic radiographic exposures and (b) to provide data normalized to DAP for the determination of patient effective and gonadal dose from panoramic radiography performed in any laboratory. A pencil ionization chamber commonly used to measure CT dose index (CTDI) in CT scanners was employed to determine DWP for various combinations of panoramic exposure settings at the beam exit slit of a Cranex Tome panoramic x-ray unit (Soredex, Helsinki, Finland). DWP values were also measured using an array of thermoluminescence dosimeters. Reproducibility of the DWP measurement was tested. The effect of milliamperage and kilovoltage of panoramic exposures on DWP was investigated. DAP was estimated using the value of DWP measured using the pencil ionization chamber and the beam exit slit length measured using dosimetric film attached on the beam exit slit. A Rando anthropomorphic phantom appropriately loaded with thermoluminescent dosimeters (TLDs) was used to obtain organ dose and effective dose values from panoramic radiography. Reproducibility of DWP determination using the proposed method was better than 1.5%. DWP was found to be linearly related to milliamperage (r>0.999, p<0.001) and to kilovoltage raised in a power ranging from 2.18 to 2.55. DWP measured using the pencil chamber was found to be up to 11% higher than the corresponding values determined using TLD array. The panoramic exposure obtained with settings appropriate for the typical adult patient was found to result in 0.008 mSv patient effective dose, 0.0002 mGy gonadal dose, and 11.3 cGy cm2 DAP. The use of a pencil ionization chamber is proposed for the determination of DWP and DAP from panoramic radiographic exposures. Normalized data over DAP were provided for the determination of patient effective and gonadal dose from panoramic radiography.

Accuracy of digital and film panoramic radiographs for assessment of position and morphology of mandibular third molars and prevalence of dental anomalies and pathologies

OBJECTIVES

To compare the accuracy of digital and film panoramic radiographs for determining (1) the position and morphology of mandibular third molars before surgical removal and (2) the prevalence of dental anomalies and pathologies.

METHODS

Three hundred and eighty-eight third mandibular molars were available for examination. Position and morphology of third molars observed on film radiographs and on digital panoramic images from five systems (DenOptix, DigiDent, Digora, Dimax2 and Orthophos Plus) were recorded by two observers and were compared with surgeons' findings at the time of the operation (gold standard). One observer further recorded the prevalence of dental anomalies and pathologies on both imaging modalities.

RESULTS

Few differences were found between the digital and film-based panoramic systems in the assessment of accuracy of position and morphology of mandibular third molars. The prevalence of dental anomalies and pathologies determined with the two modalities was roughly similar.

CONCLUSION

The five digital panoramic systems evaluated in this study were equally as useful for third molar treatment planning and diagnosis of dental anomalies and pathologies as conventional film-based panoramic radiographs.

Routine panoramic radiography of new adult patients in general dental practice: relevance of diagnostic yield to treatment and identification of radiographic selection criteria

OBJECTIVES

We sought to measure the diagnostic yield of relevance to treatment on routine panoramic radiographs taken of new adult (ie, 18 years and over) patients in general dental practice.

STUDY DESIGN

Routine panoramic radiographs (n = 1817) obtained from general dental practice were assessed and radiologic yield recorded using consensus viewing by 2 dental radiologists. A modified diagnostic yield of relevance to treatment for each radiograph was calculated by omission of findings that would have been identified on bilateral posterior bitewing radiographs and of radiologic findings of no relevance to treatment. Stepwise logistic regression analysis was used in attempt to identify clinical indicators of a high diagnostic yield of relevance to treatment.

RESULTS

The diagnostic yield of relevance to treatment was zero for the majority (56%) of patients. This figure rose to 71% when the symptom-free patients were considered. Five clinical indicators for panoramic radiography were identified, as follows: clinical suspicion of teeth with periapical pathologic conditions, presence of partially erupted teeth, clinically evident caries lesions, swelling, and clinically suspected unerupted teeth.

CONCLUSION

Routine panoramic radiography of adult dental patients is not supported by the results of this study. The use of clinical indicators to select patients may help to improve diagnostic yield.

[Non-invasive evaluation of an injectable bone substitute]

Despite the increasing number of techniques for the preservation of bone ridges after dental avulsion, no precise evaluation of alveolar filling has been performed to date. The criteria of available measurement techniques (probes, retroalveolar or panoramic radiography, and lateral teleradiography) are not sufficiently reliable and precise. This study investigated the reliability of evaluation based on CT images in comparison with retroalveolar radiography (the most precise radiographic technique, providing standardised images), direct measurements, and images obtained in scanning electron microscopy. After a preliminary investigation ex vivo, a study was performed in vivo on three beagles. Mandibular premolars were extracted, and the corresponding alveoli were filled with an injectable bone substitute composed of a calcium phosphate mineral load associated with hydroxypropyl methylcellulose. Measurements performed on CT images relative to visual and automatic detection of density changes and studies of density curves provided better precision than those obtained by retroalveolar radiography.

Screening panoramic radiography of new adult patients: diagnostic yield when combined with bitewing radiography and identification of selection criteria

OBJECTIVES

To measure the radiological diagnostic yield on screening panoramic radiographs taken of new adult patients and to identify selection criteria for panoramic radiography of new adult patients.

DESIGN

Survey of 1,817 consecutive panoramic radiographs taken as 'routine' on new patients with statistical analysis of clinical and radiological findings.

SETTING

All radiographs were obtained from 41 general dental practitioners (GDPs). The GDPs provided the clinical information about the patient obtained by history and examination. Collection of material occurred in 1998/1999.

MATERIALS AND METHODS

Two dental radiologists recorded the radiological findings on each of 1,817 panoramic radiographs by consensus. Those findings that would have been identified from bilateral posterior bitewing radiographs of each patient were then excluded to give modified figures for radiological findings.

MAIN OUTCOME MEASURES

Indices of diagnostic yield were devised and calculated for each radiograph from the data on radiological findings. Total diagnostic yield (DY) and modified diagnostic yield (MDY), after exclusion of findings identifiable on bitewing radiographs, were both calculated. Clinical indicators of a high MDY were identified using stepwise multiple regression analysis.

RESULTS

MDY was 0 for 17% of the radiographs (all patients) and 23% of the radiographs when the asymptomatic group were considered. The clinical variables for which the significance was high (p < 0.001) were: increasing number of teeth with clinical suspicion of periapical pathology, presence of partially erupted teeth, increasing number of clinically evident carious lesions, partially dentate status and presence of crowns.

CONCLUSION

Taking posterior bitewing radiographs of new adult patients would reduce the diagnostic yield identified solely by panoramic radiography. Using clinical factors derived from the history and examination as radiographic selection criteria modestly improves the odds of achieving a high diagnostic yield from panoramic radiography.

Screening panoramic radiology of adults in general dental practice: radiological findings

AIM

To identify the radiological findings from routine screening panoramic radiographs taken of adult (> or = 18 years) patients in general dental practice.

METHOD

Forty-one general dental practitioners (GDPs) who routinely took panoramic radiographs of all new adult patients were recruited. In total, they submitted 1,818 panoramic radiographs of consecutive patients along with basic patient information, radiological reports and treatment plans. The radiographs were also reported by 'experts' (consensus of two dental radiologists). Radiological findings were recorded from the GDP assessments (dentist RY), the experts (expert RY), after exclusion of findings that would have been seen on posterior bitewing radiographs (MRY) and after exclusion of findings of no relevance to treatment (MRYT).

RESULTS

There was no significant difference in age profile between the study sample and Dental Practice Board population figures (P = 0.26). No radiographs other than the panoramic radiograph had been taken for 57.1% of patients. For the GDP assessments, only 4.6% of patients had radiographs with no radiological findings, while for the experts this proportion was 3.1%. With the exception of the assessment of periodontal bone loss, the experts diagnosed significantly greater proportions of cases as having positive radiological findings. Agreement between dentist and expert assessments varied greatly. When findings from bitewing radiographs were excluded, no radiological findings were recorded on the radiographs of 17.2% of patients. When proposed treatment plans were taken into account, the majority of patients' radiographs (56.3%) had no radiological findings of relevance to treatment.

CONCLUSIONS

The choice of radiographic examination for the majority of patients in the study did not follow current guidelines. Dentists diagnosed fewer abnormalities than did experts. While many radiological findings are revealed by panoramic radiography, these may either duplicate information from bitewing radiographs or are often of no significance to treatment planning. This study did not provide evidence to support the practice of routine panoramic radiography of all new adult patients.

Advances in dental imaging

The number of dental radiographs taken in the UK has steadily increased over the past 20 years--recently estimating around 18 million taken in the general dental services alone, and dental radiographs now account for nearly 25% of all medical radiographic exposures. Radiographs remain our most useful diagnostic aid. Their strength is in demonstrating hard tissue pathology, which makes radiographs particularly effective in the maxillofacial region. Although well accepted in this capacity, there remain a number of limitations and drawbacks to conventional radiographs which recent developments have begun to overcome. There have been improvements in the scope and capabilities of dental imaging equipment. There has also been a continuing effort to reduce radiation-induced harm by limiting our exposure to it. This has been possible both through the introduction of new methods and protocols for reducing individual radiation exposures and by the creation of guidelines for selecting radiographs more effectively and thereby reducing the total number of radiographs taken.

Occlusal caries diagnosis in molar teeth from bitewing and panoramic radiographs

INTRODUCTION

Previous studies have implied that the panoramic radiograph was inferior to the bitewing radiograph for caries diagnosis. However, these clinical studies lacked a method of validation. The aim of this study was to use an electronic caries meter (ECM II, LODE, Groningen, The Netherlands) to validate occlusal caries diagnosis made from bitewing and panoramic radiographs.

MATERIALS AND METHOD

Forty-nine Army recruits were examined with the ECM, and had bitewing and panoramic radiographs taken. In total 299 molar occlusal surfaces were available for examination. Seven examiners viewed the bitewing and panoramic radiographs on two separate occasions and assessed each occlusal surface for dentine caries as 1: almost definitely no caries, 2: probably no caries, 3: unsure, 4: caries probably present, and 5: caries almost definitely present. This was repeated on 20% of the radiographs at two further separate sittings. ECM conductance readings greater than 9 were taken to indicate dentine caries. Examiner decisions that caries was probably and definitely considered to be present were taken as positive diagnoses.

RESULTS

Bitewing and panoramic radiographs provided sensitivity values of 0.25 and 0.19 and specificity values of 0.93 and 0.97 respectively. ROC analysis indicated no statistically significant difference in diagnostic quality between the bitewing and panoramic radiographs. Intra-examiner reproducibility was found to be poor to moderate (Kappa values for bitewing = 0.31-0.44, panoramic = 0.07-0.54).

CONCLUSION

No difference in overall diagnostic performance was found between bitewing and panoramic radiographs for the diagnosis of occlusal dentine caries.

Quality evaluation of young adults' radiographs in Finnish public oral health service

OBJECTIVE

To evaluate the quality of young adults' radiographs exposed and processed under everyday clinical conditions.

SETTING

One administrative unit of the Finnish public oral health service.

DESIGN

Two reviewers independently evaluated the radiographs by the same written criteria that were designed as a checklist for on-site evaluations, without any further calibration.

SAMPLE

In total, 312 radiographs (178 bitewing, 88 periapical and 46 panoramic) from 1990 to 1996, collected from patient documents of a randomly selected sample of young adults born in 1966-1971.

OUTCOME MEASURES

Radiographs were assessed by quality indicators pertinent to the clinical utility as acceptable or unacceptable. If erroneous by some indicator(s) but still contributing to the diagnostic information, a radiograph was rated as diagnostically acceptable. A score of quality points was calculated for each radiograph.

RESULTS

The overall kappa statistics for intra-examiner reliability was 0.63, the proportional agreement 83%. For inter-examiner reliability, 0.42 and 71%, respectively. Although the evaluation criteria took the clinical utility of the radiographs into consideration, only 15% of bite-wings, 13% of periapicals, and 2% of panoramics received the maximum quality points. Erroneous film positioning was the most common fault on intraoral radiographs. On panoramics, the most frequent faults were in density and contrast and in patient positioning. The radiological evaluation had only been recorded for less than one fifth of the films.

CONCLUSIONS

A proportion of radiographs fell short of the ideal. There is room for improvement in the quality of radiography in order to obtain the greatest possible diagnostic yield from the exposed radiographs.

Detection of dentine caries using the oblique lateral radiograph

OBJECTIVES

The aim of the study was to evaluate the level of agreement between bitewing radiographs and oblique lateral radiographs for the diagnosis of dental caries extending into dentine, and to draw conclusions from the results as to which view is more useful.

SAMPLE

Radiographs were selected from patients attending an orthodontic assessment clinic: 53 patients, 52% male, 48% female, aged 6-18 years old. Total 105 bitewings and 105 oblique lateral radiographs.

METHODS

Contemporaneous bitewing and oblique radiographs taken over the period 1987-97 were independently assessed by two dentists for the presence of caries extending into dentine.

RESULTS

The agreement between the oblique lateral and the bitewing radiographs for the presence of approximal caries expressed in the form of Cohen's Kappa gave values of 0.64 for observer 1 and 0.53 for observer 2. For occlusal caries, values were 0.72 for observer 1 and 0.56 for observer 2. Kappa values for the level of agreement between observers and for the same observer on different occasions were within the range 0.5-0.95 for both types of film.

CONCLUSION

The Kappa values for the agreement between the two views as well as the intra- and inter-observer agreement and reproducibility of the oblique lateral view all fall in the range K = 0.5-0.75. Results suggested a fair to good agreement in diagnoses made using the two types of film. However, levels were lower than estimates of reproducibility reported for bitewing films alone.

Factors influencing the selection of panoramic radiography in general dental practice

OBJECTIVES

To identify factors influencing dentists' decisions to take panoramic radiographs and to determine dentists' perceptions of the value of panoramic radiographs in the diagnosis of common dental pathologies.

METHODS

Questionnaire of dentists with access to panoramic radiography equipment in 22 randomly selected Family Health Service Authorities in England and Wales. Dentists were asked to score 17 factors for their influence upon panoramic use, compare the relative diagnostic value of panoramic and intraoral radiographs for diagnosis of common dental pathologies and state their principal reasons for taking panoramic radiographs.

RESULTS

The response rate to the questionnaire was 73.3%. The factors most likely to influence dentists to take a panoramic radiograph were 'planning oral surgery', 'facial trauma', 'periodontal disease', 'heavily restored dentition' and 'patient first attendance'. Dentists' opinions on the diagnostic usefulness of panoramic radiographs were in broad agreement with those in the scientific literature. The main reasons for taking panoramic radiographs were as a 'general screen' and as a 'view for unerupted or impacted teeth'.

CONCLUSIONS

There are areas where dentists' prescription of panoramic radiographs is in disagreement with recent guidelines. Successful implementation of these guidelines would be likely to lead to a substantial reduction in the numbers of panoramic radiographs taken by GDPs.

Aspects of panoramic radiography in general dental practice

OBJECTIVES

To gather information on the types of panoramic x-ray equipment used in NHS dental practice and whether dentists satisfy the legal requirements for safety, to determine which practice personnel take panoramic radiographs and to assess the prevalence of the practice of 'routine' panoramic radiography among NHS dentists.

DESIGN

Postal questionnaire survey of general dental practitioners carried out during 1997 in selected FHSAs in England and Wales.

RESULTS

542 dentists returned the questionnaire, a 73.3% response. Panoramic x-ray equipment ranged in age from 27 years old to new, with 42.2% exceeding 10 years in age. The overwhelming majority of GDPs satisfied the requirement for regular maintenance and surveying of equipment. Almost all dentists (95.9%) performed a history and clinical examination prior to panoramic radiography but 42% practised 'routine screening' of new adult patients. A substantial proportion (36.7%) of dentists used unqualified personnel to take panoramic radiographs.

CONCLUSIONS

While some aspects of this study give reassurance about the prevalence of good practice, widespread panoramic screening and using unqualified staff to take radiographs causes concern. These findings have implications for educators and for those involved in maintaining clinical standards.

Practical periodontal screening and diagnosis

The differences in approach between screening for and diagnosis of periodontal diseases are highlighted. The Periodontal Screening and Recording procedure is discussed in terms of its evolution and current application. For patients screened and found to have more advanced periodontal problems a panoramic dental radiograph with restricted supplemented periapicals are recommended. A comprehensive clinical periodontal examination should be performed for these patients, but it is argued that this may be performed after the initial hygiene phase of treatment. In establishing a diagnosis it is suggested that attention be paid to possible risk exposures. Newer, non-anatomic diagnostic procedures are discussed in principle and it is concluded that these do not have a practical application at present.

Digital radiography and caries diagnosis

Direct digital acquisition of intra-oral radiographs has been possible only in the last decade. Several studies have shown that, theoretically, there are a number of advantages of direct digital radiography compared with conventional film. Laboratory as well as controlled clinical studies are needed to determine whether new digital imaging systems alter diagnosis, treatment and prognosis compared with conventional methods. Most studies so far have evaluated their diagnostic performance only in laboratory settings. This review concentrates on what evidence we have for the diagnostic efficacy of digital systems for caries detection. Digital systems are compared with film and those studies which have evaluated the effects on diagnostic accuracy of contrast and edge enhancement, image size, variations in radiation dose and image compression are reviewed together with the use of automated image analysis for caries diagnosis. Digital intra-oral radiographic systems seem to be as accurate as the currently available dental films for the detection of caries. Sensitivities are relatively high (0.6-0.8) for detection of occlusal lesions into dentine with false positive fractions of 5-10%. A radiolucency in dentine is recognised as a good predictor for demineralisation. Radiography is of no value for the detection of initial (enamel) occlusal lesions. For detection of approximal dentinal lesions, sensitivities, specificities as well as the predictive values are fair, but are very poor for lesions known to be confined to enamel. Very little documented information exists, however, on the utilization of digital systems in the clinic. It is not known whether dose is actually reduced with the storage phosphor system, or whether collimator size is adjusted to fit sensor size in the CCD-based systems. There is no evidence that the number of retakes have been reduced. It is not known how many images are needed with the various CCD systems when compared with a conventional bitewing, nor how stable these systems are in the daily clinical use or whether proper cross-infection control can be maintained in relation to scanning the storage phosphor plates and the sensors and the cable. There is only sparse evidence that the enhancement facilities are used when interpreting images, and none that this has changed working practices or treatment decisions. The economic consequences for the patient, dentist and society require examination.