Audit of a 5-year radiographic protocol for assessment of mandibular third molars before surgical intervention

OBJECTIVES

To perform an audit of a three-step protocol for radiographic examination of mandibular third molars before surgery.

METHODS

1769 teeth underwent surgery. A standardized three-step radiographic protocol was followed: (1) panoramic imaging (PAN), (2) stereoscanography (SCAN) and (3) CBCT. If there was overprojection between the tooth and the canal in PAN, SCAN was performed. If the tooth was determined to be in close contact with the canal in SCAN, CBCT was performed. Close contact between the tooth and the canal was assessed in all images, and patient-reported sensory disturbances from the alveolar inferior nerve were recorded after surgery. The relation between the final radiographic examination and sensory disturbances was determined. Logistic regression analysis tested whether signs for a close contact in PAN/SCAN could predict no bony separation between the tooth and canal in CBCT.

RESULTS

46% of teeth underwent PAN, 31% underwent SCAN and 23% underwent CBCT as the final examination. 21% underwent all three radiographic examinations. 53/76% of teeth with close relation to the canal in PAN/SCAN showed no bony separation in CBCT; if there was close relation in PAN/SCAN, there was 1.6/4.3 times higher probability that no bony separation existed in CBCT. 16 cases of sensory disturbances were recorded: 4 operations were based on PAN, 8 on SCAN and 4 on CBCT.

CONCLUSIONS

The radiographic protocol was in general followed. SCAN was superior to PAN in predicting no bony separation between the tooth and the canal in CBCT, and there was no relation between sensory disturbances and radiographic method.

Reproducibility of mandibular third molar assessment comparing two cone beam CT units in a matched pairs design

The aim of this study was to evaluate the reproducibility of the third molar assessment, comparing five observers and two cone beam CT (CBCT) units. 28 patients, each with two impacted mandibular third molars, were included. Each patient was randomly examined with a Scanora(®) 3D (Soredex, Helsinki, Finland) CBCT unit in one mandibular third molar region and with a Cranex(®) 3D (Soredex) CBCT unit in the other region. Five observers with varying CBCT experience assessed all third molars and recorded the following variables: number and morphology of the roots, relation to the mandibular canal in two directions, shape of the canal and whether there was a direct contact between the roots of the molar and the mandibular canal. The radiographic assessments were compared pairwise among all observers for all variables. Wilcoxon's signed-rank test was used to test the differences in observer accordance percentages among the recorded variables in the images from the two units, and kappa statistics expressed interobserver reproducibility. The mean percentages for observer accordance ranged from 65.4 to 92.9 for Scanora 3D and 60.3 to 94.8 for Cranex 3D. There was no significant difference between the observer accordance in the two CBCT units (p > 0.05), except for assessing root flex in the mesiodistal direction, for which the observer accordance was higher for Scanora 3D (p < 0.05). Kappa values ranged from 0.1 to 1.0 for Scanora 3D and from 0.2 to 0.9 for Cranex 3D. For the variable "direct contact", the interobserver reproducibility was excellent for the two trained radiologists. The two units had almost similar interobserver reproducibility for mandibular third molar assessment. Observer variation existed, and experienced radiologists demonstrated the highest interobserver reproducibility for canal-related variables.

Influence of cone beam CT on treatment plan before surgical intervention of mandibular third molars and impact of radiographic factors on deciding on coronectomy vs surgical removal

OBJECTIVES

To assess the influence of cone beam CT (CBCT) on treatment plan before surgical intervention of mandibular third molars and to identify radiographic factors with an impact on deciding on coronectomy.

METHODS

186 mandibular third molars with an indication for surgical intervention underwent a radiographic examination with two methods: (1) panoramic imaging in combination with stereo-scanography and (2) CBCT. After the radiographic examination a treatment plan (TP) was established: either surgical removal (Sr) or coronectomy (Co). The first TP was based on the panoramic image and stereo-scanogram, while the second TP was established after CBCT was available. Logistic regression analyses were used to identify factors predisposing for Co after CBCT.

RESULTS

Treatment was performed according to the second TP. Agreement between the first and second TP was seen in 164 cases (88%), while the TP changed for 22 teeth (12%) after CBCT. Direct contact between the third molar and the mandibular canal had the highest impact on deciding on Co [odds ratio (OR) = 101.8, p < 0.001]. Direct contact was not a sufficient factor, however; thus, lumen narrowing of the canal (OR = 38.9-147.2, p < 0.001) and canal positioned in a bending or a groove in the root complex (OR = 32.8, p = 0.016) were additional canal-related factors for deciding on Co.

CONCLUSION

CBCT influenced the treatment plan for 12%. Direct contact in combination with narrowing of the canal lumen and canal positioned in a bending or a groove in the root complex observed in CBCT images were significant factors for deciding on coronectomy.

Periapical and endodontic status of permanent teeth in patients with hypophosphatemic rickets

Hypophosphatemic rickets (HR) is a rare hereditary disease in which dental problems in terms of spontaneous periapical infections are frequently reported. Most previous reports have been based on a small number of HR patients and have been published before the disease could be confirmed genetically. The aim of the present study was to describe the periapical and endodontic status of permanent teeth in patients with genetically and/or biochemically confirmed HR. The patients were recruited from a medical study on HR patients. The patients underwent a dental examination including a digital panoramic radiograph, which was scored for endodontically affected teeth (i.e. teeth with periapical radiolucencies and/or endodontically treated teeth). A total of 52 patients (age range: 5·7-74·5 years; 17 males and 35 females) were included. HR patients were characterised by a high number of endodontically affected teeth (mean: 4·2; s.d.: 5·0). The number of affected teeth rose significantly with age (P < 0·01), and no statistically significant gender difference was found. The relative distribution of endodontically affected teeth in the three tooth groups (incisors and canines, premolars, and molars) varied according to age. In the youngest age group, only incisors and canines were affected, while the relative proportion of affected premolars and molars increased with age. Endodontically affected teeth are common in HR patients, and the number of affected teeth increased significantly with age. Hence, the need for endodontic treatment among HR patients is comprehensive.

Effect of monitor display on detection of approximal caries lesions in digital radiographs

OBJECTIVES

The aim was to compare the accuracy of five flat panel monitors for detection of approximal caries lesions.

METHODS

Five flat panel monitors, Mermaid Ventura (15 inch, colour flat panel, 1024 x 768, 32 bit, analogue), Olórin VistaLine (19 inch, colour, 1280 x 1024, 32 bit, digital), Samsung SyncMaster 203B (20 inch, colour, 1024 x 768, 32 bit, analogue), Totoku ME251i (21 inch, greyscale, 1400 x 1024, 32 bit, digital) and Eizo FlexScan MX190 (19 inch, colour, 1280 x 1024, 32 bit, digital), were assessed. 160 approximal surfaces of human teeth were examined with a storage phosphor plate system (Digora FMX, Soredex) and assessed by seven observers for the presence of caries lesions. Microscopy of the teeth served as validation for the presence/absence of a lesion.

RESULTS

The sensitivities varied between observers (range 7-25%) but the variation between the monitors was not large. The Samsung monitor obtained a significantly higher sensitivity than the Mermaid and Olórin monitors (P<0.02) and a lower specificity than the Eizo and Totoku monitors (P<0.05). There were no significant differences between any other monitors. The percentage of correct scores was highest for the Eizo monitor and significantly higher than for the Mermaid and Olórin monitors (P<0.03).

CONCLUSIONS

There was no clear relationship between the diagnostic accuracy and the resolution or price of the monitor. The Eizo monitor was associated with the overall highest percentage of correct scores. The standard analogue flat panel monitor, Samsung, had higher sensitivity and lower specificity than some of the other monitors, but did not differ in overall accuracy for detection of carious lesions.

Cone beam CT and conventional tomography for the detection of morphological temporomandibular joint changes

OBJECTIVE

To compare the diagnostic accuracy of cone beam CT images with conventional tomographic images for the detection of morphological temporomandibular joint (TMJ) changes.

METHODS

80 dry human skulls were scanned using a NewTom 3G scanner and lateral and frontal reconstructions of the right and the left TMJs were performed. In addition, lateral and frontal cross-sectional tomograms of the skulls' TMJs were obtained in a Cranex Tome unit with Digora storage phosphor plates. Naked-eye inspection of the TMJs performed by three observers served as the gold standard for the true presence of morphological changes. The mandibular fossae were excluded from the study due to few changes in this joint component. The NewTom and the conventional tomographic images were examined by three independent observers using a binary scale for the presence of morphological changes in the condyle (flattening, defects and osteophytes) and the articular tubercle (flattening and defects). The accuracy for the different types of changes in relation to the condyles and the articular tubercles was expressed as sensitivity and specificity values, whereas the diagnostic accuracy for a general assessment including all changes in both joint components was expressed by the sum of cases where the gold standard and the radiographic scores were not identical (absolute difference). Differences between the two radiographic modalities were tested by paired t-test.

RESULTS

Detection of the various types of morphological changes in relation to the condyle and the articular tubercle assessed separately resulted in no significant differences between the two radiographic modalities, with the exception of bone defects in the articular tubercle examined on frontal views alone where the specificity with tomography was significantly higher than with cone beam CT. Detection of all morphological changes in relation to both the condyle and the articular tubercle showed a significantly higher accuracy with tomography than with cone beam CT using lateral views alone, but there was no significant difference between the two modalities using frontal views alone and lateral and frontal views in combination.

CONCLUSION

In general, no significant differences in diagnostic accuracy for the detection of bone changes in the condyle and in the articular tubercle were found between cone beam CT images and conventional tomograms.

Comparison of diagnostic accuracy of film and digital tomograms for assessment of morphological changes in the TMJ

OBJECTIVE

To compare diagnostic accuracy of tomograms obtained with film and three digital image receptor modalities for detection of morphological changes in the temporomandibular joint (TMJ).

METHODS

Lateral and frontal cross-sectional tomograms of 158 TMJs in 80 dry human skulls were obtained with four X-ray receptors: one conventional film (Agfa-Gevaert), two photostimulable phosphor (PSP) plates: VistaScan and Digora PCT and one charge-coupled device (CCD): ProMax. The film and the PSP plate tomograms were exposed in a Cranex Tome X-ray unit and the CCD tomograms in the ProMax X-ray unit. The tomograms were examined by three observers for the presence of morphological changes in the condyle, the mandibular fossa and the articular tubercle. Naked-eye inspection of the articular surfaces of the TMJs performed by the same three observers served as the gold standard for the true presence of morphological changes.

RESULTS

For examination of TMJ changes using lateral and frontal tomograms in combination and lateral tomograms separately, the ProMax modality obtained a significant lower diagnostic accuracy than the other three modalities, between which no significant differences were found. For morphological changes localized to the condyle in which the highest number of changes were present according to the gold standard, the same result was found.

CONCLUSION

The ProMax modality was significantly less accurate than the film, VistaScan and Digora PCT modalities for the detection of overall TMJ morphological bone changes as well as condylar bone changes.

Diagnostic accuracy of two software modalities for detection of caries lesions in digital radiographs from four dental systems

OBJECTIVE

To compare the caries diagnostic accuracy of two software modalities used in the assessment of digital radiographs obtained with four different dental systems, and to evaluate whether the software used for image assessment influenced the mutual comparison of those four dental systems relating to their caries diagnostic accuracy.

METHODS

Under in vitro and standardized conditions 122 teeth (with 228 unrestored approximal and 99 occlusal surfaces) were radiographed in blocks of 3 test teeth and 2 non-test teeth using two storage phosphor plate systems: Digora (Soredex, Helsinki, Finland) and DenOptix (Gendex, Dentsply, Milan, Italy) and two charge coupled device (CCD)-based sensor systems: Dixi (Planmeca, Helsinki, Finland) and Sidexis (Sirona, Bensheim, Germany). The images were displayed and examined in two software modalities: their own dedicated software and a general software. Three observers examined all images for the presence of approximal enamel and dentine and occlusal dentine caries lesions using a 5-point confidence scale. The true presence of caries was validated by ground section histology. The diagnostic accuracy of the software modalities was expressed as ROC curve areas (A(z)) and differences between modalities were tested by paired t-test. Comparison of systems was analysed by post hoc t-test.

RESULTS

Results of approximal and occlusal surfaces assessed together revealed nearly identical mean A(z) with the two software modalities on images obtained with the Digora (A(z)=0.71) and DenOptix (A(z)=0.72) systems. On Dixi images the mean A(z) was 0.75 using the system's own software and 0.73 using the general software. On Sidexis images the corresponding mean A(z)s were 0.79 and 0.75. None of those differences were significant.

CONCLUSION

No significant difference in caries diagnostic accuracy was found between two software modalities used for examination of digital radiographs obtained with four different digital systems, and the software modality did not influence the mutual rank of the four systems relating to their diagnostic accuracy.

Comparison of standard and task-specific enhancement of Digora storage phosphor images for approximal caries diagnosis

OBJECTIVES

To compare approximal caries detection on Digora storage phosphor images pre-enhanced with the automatic "caries-specific Oslo enhancement procedure" ("Oslo-enhanced" method) and storage phosphor images individually enhanced by observers particularly experienced in digital imaging using standard brightness and contrast functions of the Digora system ("Digora-enhanced" method).

METHODS

Seven staff members from four oral radiology departments rated 240 approximal surfaces for caries with regard to lesion depth in the inner and outer half of the enamel and dentine, using a 5-point confidence scale. The observations were validated histologically. A receiver operating characteristic (ROC) analysis and an analysis of variance with three dependent variables (observer confidence, observer signed error and observer absolute error) were performed.

RESULTS

The most evident difference between the methods as elucidated by the ROC analysis was the highly significant smaller interobserver and intraobserver variance with the Oslo-enhanced method for all but one observer. The methods were not different with regard to average diagnostic accuracy (A(z) values) as tested with paired t-tests, and there was no correlation between A(z) across methods. The method and lesion main effects, as well as the lesion by method interaction effect, were multivariately significant (P<0.001) in favour of the Oslo-enhanced method. On a univariate level, the method main effect was not significant for the absolute observer error (P=0.330). All other univariate effects were significant (P<0.001).

CONCLUSIONS

The accuracy of approximal caries detection with Digora storage phosphor images pre-enhanced and images individually enhanced was similar, but interobserver and intraobserver variability improved with the Oslo-enhanced method. Since image manipulation is not performed with the Oslo-enhanced method, the increased speed of the diagnostic procedure combined with the improved observer variability would probably be even more pronounced for the general dental practitioner.

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.

Image quality of two solid-state and three photostimulable phosphor plate digital panoramic systems, and treatment planning of mandibular third molar removal

OBJECTIVES

The purpose was to evaluate image quality of two solid-state (charge-coupled device (CCD)) and three photostimulable phosphor (PSP) plate digital panoramic systems, and to assess their utility for treatment planning before mandibular third molar removal.

METHODS

433 patients were randomly allocated to five digital systems: Dimax2 and Orthophos Plus (both CCD systems) and DenOptix, DigiDent and Digora (all PSP systems). Image quality was evaluated in six regions on a 4-point scale by three independent observers. In addition, an oral surgeon evaluated image quality in the mandibular third molar region only as well as the utility of the image for treatment planning before removal of that molar.

RESULTS

Images from the DenOptix and DigiDent systems had a significantly lower overall quality than images from the Digora, Dimax2 and Orthophos Plus systems (P < 0.005). The oral surgeon's assessment of image utility resulted in rejection rates of 0% for Orthophos Plus, 2% for Digora, 8% for Dimax2, 12% for DigiDent and 14% for DenOptix images. The rates for the DigiDent and DenOptix images were significantly higher than those for the other systems (P < 0.001), and the rate for Dimax2 was significantly higher than that for Orthophos Plus (P = 0.002).

CONCLUSIONS

The quality of DenOptix and DigiDent digital panoramic images was found to be inferior to the quality found in images obtained with the Digora, Dimax2 and Orthophos Plus systems. Images from the Digora and Orthophos Plus systems were regarded to be the most useful for treatment planning before mandibular third molar removal.

Accuracy of caries detection with four storage phosphor systems and E-speed radiographs

OBJECTIVE

To evaluate the accuracy of caries detection using four intra-oral storage phosphor plate systems exposed with two different exposure times and one film system.

METHODS

Under in vitro and standardised conditions 365 approximal and 159 occlusal surfaces were radiographed using four storage phosphor plate systems: DenOptix, Cd-dent, Digora (blue and white plates) and one film system: Ektaspeed Plus. The plates were exposed twice with 10% and 25% of the time needed for the film. Four observers recorded approximal enamel/dentine and occlusal dentine caries using a five-point confidence scale. Caries presence was validated histologically and diagnostic accuracy of the systems by using ROC curve areas (Az).

RESULTS

The shorter exposure time for approximal caries, Digora(white)(Az=0.68) and Ekta Plus (Az=0.69) were significantly more accurate than the other systems (Az=0.64-0.65). For occlusal caries using the same exposure time, no significant difference was found between the digital systems (Az=0.76-0.77), which all showed to be significantly less accurate than Ekta Plus (Az=0.81). Using the longer exposure time for approximal caries, no significant difference was found between DenOptix (Az=0.68), Digora(blue) (Az=0.69), Digora(white) (Az=0.69) and Ekta Plus (Az=0.69) which were all significantly more accurate than Cd-dent (Az=0.65). For occlusal caries using the same exposure time, Digora(blue) (Az=0.81) was the most significantly accurate of the digital systems. When approximal caries was the diagnostic task, the longer exposure time resulted in significantly higher accuracy with the DenOptix and Digora(blue) systems but not with the Cd-dent and Digora(white) systems. For occlusal caries, the longer exposure time resulted in a significant improvement only with the Digora(blue) system.

CONCLUSION

For approximal caries using the longer exposure time, no significant difference in diagnostic accuracy was found between DenOptix, Digora(blue), Digora(white) and Ekta Plus which were all significantly more accurate than the Cd-dent. For occlusal caries using the longer exposure time, Digora(blue) was found to be the most accurate of the digital systems. The exposure time had an influence on the diagnostic accuracy with the DenOptix and Digora(blue) systems for approximal and with the Digora(blue) system for occlusal caries detection.

Influence of the validation method on diagnostic accuracy for caries. A comparison of six digital and two conventional radiographic systems

OBJECTIVE

To evaluate the influence of the validation method on the diagnostic accuracy and the relative comparison of eight radiographic systems for caries detection.

METHODS

Three hundred and thirty-eight approximal and 145 occlusal surfaces were radiographed under standardised conditions using six CCD-based sensor systems: MPDx (Dental/Medical Diagnostic Systems Inc., Woodland Hills, CA, USA), Dixi (Planmeca, Helsinki, Finland), Sidexis (Sirona, Bensheim, Germany), RVG(old) (Trophy, Paris, France, 1994 model), RVG(new) (Trophy, Paris, France, 2000 model) and Visualix (Gendex, Milan, Italy) and two film systems: Ektaspeed Plus and Insight (Eastman Kodak, Rochester, NY, USA). Four observers examined the radiographs for approximal and occlusal caries using a five-point confidence scale. The presence of caries was validated histologically and radiographically. Diagnostic accuracy was evaluated using ROC curve areas (A(z)).

RESULTS

For both approximal and occlusal caries the mean A(z) of the eight radiographic systems was significantly higher using radiographic than histological validation (P<0.001). Using histological validation for approximal caries, Dixi (A(z)=0.71) and Ektaspeed Plus (A(z)=0.7) were not significantly different, but Dixi was significantly more accurate than the other digital systems and the Insight film. Using radiographic validation for approximal caries, Ektaspeed Plus (A(z)=0.87) was significantly more accurate than Dixi (A(z)=0.82). Dixi was significantly more accurate than MPDx (A(z)=0.74), RVG(old) (A(z)=0.77), RVG(new) (A(z)=0.77) and Visualix (A(z)=0.76). Corresponding variations were found for occlusal caries depending on the validation method. Using histological validation, MPDx (A(z)=0.76) was significantly less accurate than Dixi (A(z)=0.81), Sidexis (A(z)=0.8), Ektaspeed Plus (A(z)=0.82) and Insight (A(z)=0.81). Using radiographic validation, MPDx (A(z)=0.83) was also significantly less accurate than RVG(old) (A(z)=0.89) and RVG(new) (A(z)=0.9).

CONCLUSION

A(z) obtained from radiographic validation was significantly higher than A(z) obtained from histological validation. Comparison of the diagnostic efficacy for caries of the eight radiographic systems was strongly influenced by the validation method. DOI: 10.1038/sj/dmfr/4600645

Approximal caries prevalence in Danish recruits and progression of caries in the late teens: a retrospective radiographic study

This study aimed to assess radiographically the prevalence and distribution of approximal caries in Danish recruits and to estimate the rate of caries progression during the recruits' late teens. To assess caries progression radiographs taken previously (when leaving the Public Dental Health Care Service, usually at the age of 16-18) were requested. Of 676 recruits previous radiographs (taken 1-7 years earlier) were procured for 640. Approximal surfaces from 7d to 4m in the maxilla and the mandible were assessed for the absence or presence/depth of caries and restorations. Caries progression was expressed by the incidence rate indicating the number of new lesions/number of lesions with progression per 100 years. In the maxilla the average prevalence of enamel and dentine caries was 8.3 and 6.2%, respectively. Overall, 6m had the highest caries experience. In the mandible the average prevalence of enamel and dentine caries was 10.7 and 5.8%, respectively. The highest caries experience was found in 6d. Twenty percent of the recruits had no caries experience in the surfaces under study, 9% had caries experience in 1 surface, 13% in 4-5 surfaces and 25% in more than 10 surfaces. For all surfaces combined, the median incidence rate for the transition from sound to enamel caries was 2.4 surfaces per 100 years, ranging from 0.4 in mandibular 7d to 5.5 in mandibular 6d. The median rate for progression from the enamel to the outer half of the dentine was 9.2 surfaces per 100 years, ranging from 4.4 in mandibular 5m to 18.9 in mandibular 6d. The median incidence rate for progression from the outer to the inner half of the dentine was 2.3 surfaces per 100 years. However, this figure was based on a small number of events and should therefore be interpreted with caution. In conclusion, enamel and dentine caries was found in 9 and 6% of the approximal surfaces in newly called up recruits, and one quarter of the recruits had caries experience in more than 10 approximal surfaces. Generally, the development of new approximal lesions and the progression of enamel caries was a slow process during the late teens.

Reliability of visual examination, fibre-optic transillumination, and bite-wing radiography, and reproducibility of direct visual examination following tooth separation for the identification of cavitated carious lesions in contacting approximal surfaces

The aim of this study was to evaluate the diagnostic accuracy of visual, fibreoptic transillumination (FOTI), and bite-wing radiographic examination performed by 4 observers for the identification of cavitated carious lesions in contacting approximal surfaces, and to assess the inter-observer agreement with these methods and with direct visual examination conducted after tooth separation, the method used as validation for definitive determination of cavitation. A total of 338 unrestored approximal surfaces in 53 students were examined independently by 4 dentists using the diagnostic methods under study. The results from the diagnostic methods were compared with the results from the validation method for each observer. The sensitivities for identification of cavitated lesions using visual examination ranged from 0.12 to 0.50. For FOTI and radiography, the sensitivities ranged from 0.00 to 0.08 and from 0.56 to 0.69, respectively. The specificities exceeded 0.90 for all observers with all methods. Kappa values expressing inter-observer reproducibility were lowest for FOTI, followed by visual and radiographic examination. On the basis of these results, it was concluded that FOTI was the least reliable of the diagnostic methods tested. For the validation method, the inter-observer agreement was only 'substantial'. This implies that the method cannot be used as a validation for other diagnostic methods applied for the identification of cavitated carious lesions in contacting approximal surfaces. However, visual inspection after tooth separation may serve as a supplementary diagnostic tool to conventional visual and radiographic examination for clinical management of aproximal carious lesions.

Accuracy of radiographic detection of residual caries in connection with tunnel restorations

The aim of this study was to evaluate the diagnostic accuracy of radiographic examination for the detection of residual caries after tunnel preparation and filling with glass ionomer cement. Further, two different radiographic modalities were compared. Forty-five extracted human premolars and molars with clinical signs of approximal caries were selected for the study. The teeth were radiographed in order to identify surfaces with dentinal lesions suitable for tunnel preparation. Seventeen of the teeth had lesions that were as a minimum through the enamel and as a maximum into the outer half of the dentin (14 teeth = 1 lesion, 3 teeth = 2 lesions). Seventeen surgically removed third molars were thereafter included. These teeth were sound with respect to caries. The teeth were arranged in blocks with approximal contacts and radiographed using two image receptors: Ektaspeed Plus film (E) and the Digora (D) digital storage phosphor plate system. The 20 carious surfaces and 20 surfaces of the impacted teeth were prepared following the guidelines for the class II tunnel technique and filled with glass ionomer cement. The radiographic examination was repeated with both modalities after filling, and the approximal surfaces scored on the radiographs by 5 observers using the criteria: 0 = no filling, 1 = filling with residual caries, 2 = filling with no adjacent caries. All teeth except the unerupted third molars were sectioned, and the sections examined under the microscope. Residual caries was observed in 8 surfaces. On average, sensitivity was 0.25 for E and 0.32 for D, specificity 0.83 for E and 0.76 for D, positive predictive value 0.38 for E and 0.32 for D, and negative predictive value 0.75 for E and 0.77 for D. The differences between the two modalities were not statistically significant (p > 0.3). Based on the relatively small number of lesions in this study, it is suggested that radiography immediately after tunnel restoration cannot be recommended, as the diagnostic benefit from this examination seems to be minuscule.

Surface-specific electrical occlusal caries diagnosis: reproducibility, correlation with histological lesion depth, and tooth type dependence

Electrical conductance measurements are being used experimentally for occlusal caries detection. Recently, it was suggested to cover the fissure system with a conducting medium, resulting in a surface-specific measurement. It was the aim of this study to determine in vitro the reproducibility of this modified technique for occlusal caries in posterior teeth, to determine for a large study sample the correlation between the electrical measurements and histological lesion depth, and to evaluate the difference between results for premolars and molars. For the reproducibility determination, surface-specific electrical resistance measurements were made using a sample of 68 posterior teeth. Eight operators performed measurements on all teeth, and repeated measurements on 24 teeth. The validity study included the previous sample and the collected samples from two more studies, resulting in a total sample of 325 posterior teeth. One operator had performed electrical resistance measurements on all teeth in the sample. Reproducibility was good: mean Pearson's correlation coefficient 0.89 (+/-0.05) for interexaminer correlation, and 0.86 (+/-0.12) for intra-examiner correlation, using log (resistance) as the result parameter. The correlation coefficient between log(resistance) and histological lesion depth for the large sample was -0.78 for all teeth, -0.64 for premolars, and -0.73 for molars. The regression line for molars was located below the regression line for premolars: at a hypothetical histology score of 2.5 (a dentine caries threshold) the estimated resistance threshold would be 507 kOmega for premolars, and 233 kOmega for molars. Converted to Electronic Caries Monitor (ECM) readings, the difference is about 1.4 on the ECM scale. It was concluded that the in vitro reproducibility of the described surface-specific method for electrical resistance measurement is very good, even for inexperienced operators. The correlation between measurements and histological lesion depth is moderate to good. The method is sensitive to electrode area differences, which will result in different clinical cut-offs for caries diagnosis in premolar and molar teeth.

Behaviour of approximal carious lesions assessed by clinical examination after tooth separation and radiography: a 2.5-year longitudinal study in young adults

This study aimed to record and monitor over a 2.5-year period the occurrence of cavitation and lesion depth progression in approximal surfaces with radiographic caries at baseline. In total, 66 approximal sites (in 29 students), where at least one of the contacting surfaces had radiographic caries, were selected to take part in the study. A clinical examination undertaken before and after tooth separation in order to assess the presence/absence of cavitation was repeated every sixth month. To monitor lesion progression bite-wing radiographs were taken every sixth month, too. After each series of examinations, surfaces judged to be prone for disease progression were referred to operative caries treatment. In surfaces with radiographic dentinal caries at baseline the cavitation prevalence following tooth separation found at the various recall examinations ranged from 20 to 44%. In surfaces with radiographic enamel caries at baseline this prevalence ranged from 4 to 8% at the various recall examinations. In dentinal lesions found with an intact surface at baseline, the risk of cavitation development during the first 1.5-year period was assessed to be up to 22%. After this period no new cavitations were found in previously intact dentinal lesions. In intact enamel lesions the risk of cavitation formation was found to be 3% during the first 1-year period. After this period no new cavitations developed in previously intact enamel lesions. Three of 7 lesions, which showed radiographic caries progression from the outer one third to the inner two thirds of the dentine during the observation period, had intact surfaces at baseline. On the basis of these results it is recommended to re-examine carefully intact, dentinal lesions by repeated clinical examination after tooth separation and by radiography about 1-1.5 years after baseline.

A two-film versus a four-film bite-wing examination for caries diagnosis in adults

The aim of this study was to compare the caries diagnostic outcome of a two-film and a four-film routine bite-wing examination undertaken in an adult population. A digital bite-wing examination using two and four films, respectively, was performed in 174 patients. The radiographs from the two examinations were assessed jointly by 2 observers for the number of imaged surfaces in the area from the distal surface of the canine to the distal surface of the third molar and for the detection of carious lesions. Significantly more surfaces were available for examination by the four-film than by the two-film examination. Overlapping surfaces were recorded in 14 and 10%, respectively, of the surfaces imaged by the two-film and four-film set. The prevalence of primary enamel and dentinal caries was 6.8% with the two-film and 5.6% with the four-film method. In 1, 684 surfaces only imaged by the four-film method caries was detected in 20 surfaces. If these extra lesions were added to the number of lesions found by the two-film method the total disease prevalence using the last-mentioned method would increase by 2 per thousand. The majority (92-99%) of all recorded lesions were detected in surfaces located between the occlusal surface of the first premolar and the mesial surface of the third molar. The little additional diagnostic outcome obtained by the use of four instead of two films did not seem to match the extra resources (double patient charge and radiation dose, and extended scan/developing and recording time for the dentist) connected to the four-film method. Thus, it may be recommended that a routine bite-wing examination undertaken in young adults should be performed with only two films: one in each side of the mouth, placed behind the premolars and the first and second molars.

Comparison of microscopy and radiography as gold standards in radiographic caries diagnosis

OBJECTIVES

To compare the effect of the choice of gold standard on the diagnostic outcome of approximal caries detection in original and compressed digital radiographs.

METHODS

116 extracted teeth radiographed with a storage phosphor system constituted the original images. These images were compressed at 1:20 and 1:33 with the JPEG irreversible compression standard. Five radiologists scored the three sets of images for the presence of approximal caries on a five-rank confidence scale. The radiographic scores were validated by stereomicroscopy (the true gold standard). The individual ROC areas for the five observers were used to select the worst (obsworst) and the best (obsbest) performer: Their scores in the original images were used as the second and third 'gold standards' for the remaining observers. Mean ROC areas for the three observers with the three types of images were calculated using these two new 'gold standards'. Differences between the ROC areas when using microscopy, obsworst, and obsbest as the 'gold standard' were compared.

RESULTS

The mean ROC areas in the original images were 0.66, 0.74 and 0.91 using the true gold standard and obsbest and obsworst as the 'gold standards' respectively. The difference between the true gold standard and obsworst was statistically significant (P < 0.001). The mean ROC areas using the true gold standard decreased with increasing compression whereas they were constant or increased using obsworst and obsbest as 'gold standards', respectively.

CONCLUSIONS

Accuracy in approximal caries diagnosis was significantly higher when an observer was the 'gold standard' than when the true gold standard was obtained by microscopy. Paradoxically, the compressed, degraded images were more accurate than the originals when an observer was the 'gold standard' while they were less accurate with the true gold standard. Thus, results obtained using observers' scores from the radiographs which are being evaluated, as validation for the presence of caries may mislead the clinician.

Patient discomfort and cross-infection control in bitewing examination with a storage phosphor plate and a CCD-based sensor

OBJECTIVES

The aim was to compare a CCD-based sensor and a storage phosphor plate with respect to patient discomfort and the efficacy of a simple cross-infection control procedure in connection with a posterior bitewing examination.

METHODS

130 patients accepted to have one posterior bitewing of the left and right side taken with two digital radiography systems, the Digora phosphor plate and the Trophy RVG XL, CCD-based sensor system. The patients assessed their feeling of discomfort after the examination on a 100-mm. Visual Analogue Scale (VAS). Microbiological samples were taken from the RVG sensor and cord and from the Digora envelope, plate and scanner during examination of 14 patients. The samples were plated and incubated anaerobically, and the colony-forming units counted.

RESULTS

Median VAS score for discomfort was 20 min for Digora and 32 min for the RVG sensor (P < 0.001). Median total counts of cultivable bacteria were low (< 20), the majority being catalase-positive, Gram-positive cocci and Gram-positive rods, presumably skin bacteria. Only the samples taken from the enveloped Digora plate and the rubber tube coated RVG sensor immediately after exposure yielded large numbers of oral bacteria.

CONCLUSION

The phosphor plate was less unpleasant than the CCD sensor. Cross-contamination posed a minor problem for both systems when a simple, standard hygiene procedure was followed.

Discrimination between restorative dental materials by their radiopacity measured in film radiographs and digital images

The aim of this study was to investigate the possibility of differentiating between various dental restorative materials by means of their radiopacity. Ten extracted molars and ten canines/anterior teeth were selected for the study. In the molar group a class II cavity and in the canines/anterior teeth group a class III cavity were cut by airrotor. The cavities were coated with vaseline before filling with five molar- and three anterior tooth restorative materials in the following sequence: for molars: amalgam, light-cured composite, glass ionomer cement, reinforced glass ionomer cement and light-cured composite. After each filling sequence radiographs were taken of the teeth on conventional film (Ektaspeed Plus) and by two digital systems: a storage phosphor plate (Digora) and a ccd-based sensor (Sidexis). Density was measured in the films with a densitometer in three areas of "air", in three areas of the class II fillings and one area of the class III fillings. The same areas were measured in the digital images where the program calculated automatically the mean grey shade values. The density values obtained from the filling areas were taken as a proportion of the values obtained from the areas of "air". Statistically significant differences in material density when related to "air" density (Wilcoxon's test) were observed between all materials in film (p < 0.01 for molars and p < 0.02 for canines/anterior teeth). For Digora only half of the materials differed significantly which was also the case for the Sidexis system (none of the CF materials were significantly different). In conclusion, the molar filling materials could be distinguished with a high probability in film while the two digital systems were less reliable. The results may be useful in forensic dentistry.

Caries behaviour in Danish teenagers: a longitudinal radiographic study

Coinciding with the decline in caries prevalence observed among children and adolescents, changes in the distribution and progression rates of the disease have been found. The aim of this study was to assess occlusal and approximal caries behaviour and disease distribution within a group of Danish teenagers, and to determine whether the presence of occlusal fillings at baseline could be used as predictor for caries behaviour. The material used was bitewing radiographs taken twice in 197 adolescents, at the age of 14.5 years (first examination) and approximately 3 years later (second examination). Of the occlusal surfaces assessed at both examinations, 93% remained unchanged, 1% developed new carious lesions, and 6% had been filled during the study period. All occlusal dentinal lesions found at the first examination and left unrestored during the study period did not appear to have progressed. Of the approximal surfaces, 86% remained unchanged, 9% developed caries, 2% showed caries progression, and 2.5% had been filled during the study period. 22% of the approximal enamel lesions found at the first examination progressed into the dentine during the study period. 18% of all the children were responsible for 50% of the total number of new lesions and fillings. The proportion of children exhibiting new lesions at the second examination was almost evenly distributed among children with and without occlusal fillings at the first examination. In the group of children with occlusal fillings at baseline, significantly more individuals than in the other group showed new fillings and lesions with and without progression. It is concluded that the progression percentage for approximal enamel lesions to penetrate into the dentine was low, that the distribution of new carious lesions and fillings among the children was polarized, and that the presence of occlusal fillings at baseline could not be used to identify children with a specific caries behaviour.

Effect of exposure time on in vitro caries diagnosis using the Digora system

The aim of this study was to determine the in vitro diagnostic performance for approximal caries and occlusal dentine caries diagnosis of the Digora system for digital radiography in relation to the exposure time. Radiographs were made of 220 extracted human posterior teeth and cuspids at exposure time levels of 3%, 6%, 10%, 20%, and 78% of the exposure time needed for E-speed film (image sets I, II, III, IV, and V, respectively). The image sets were put in random order (III, I, IV, II, V) and assessed independently by 3 observers using a 5-point confidence scale. True caries status was determined histologically after sectioning of the teeth. Evaluated parameters were: interexaminer kappa, sensitivity, specificity, Dz3/4 (the distance of one operating point to the diagonal in the ROC domain) and area under the ROC curve. The Spearman correlation coefficients between the parameters and both exposure time and order of viewing of the sets were calculated. For approximal surfaces, the ranges of mean parameter values were: sensitivity 26-33%, specificity 93-95%, Dz3/4 0.63-0.84, area 0.61-0.69. For occlusal surfaces, the ranges were: sensitivity 52-60%, specificity 91-95%, Dz3/4 1.03-1.34, area 0.79-0.87. Out of 24 pairwise comparisons between sets V and I, 5 were significant. Out of 24 comparisons between set V and II, only 2 were significant. It was concluded that diagnostic performance is unlikely to be impaired for an exposure time as short as 6% of E-speed film exposure. When reducing the exposure time to 3% of E-speed film exposure, caries diagnosis may be impaired.

Image homogeneity and recording reproducibility with 2 techniques for serial intra-oral radiography

The present study compared recording reproducibility and image homogeneity after applying two techniques for recording of serial intra-oral radiographs: 1) a technique previously described in 1990 based on mechanical fixation between the patient, the film holder, and the x-ray tube; and 2) a newly developed technique which operates with an optical alignment provided by a light beam. Twenty adults participated in the study. Two intra-oral radiographs were taken with a 30-minute time interval of the mandibular premolar/molar and the incisor region in each individual with either of the methods. All radiographs were scanned and digitized. Subtractions were performed between the two radiographs taken of the same individual and region with the same method. The standard deviation (SD) of the histogram defining the distribution of the grey shades in the subtraction image was used as the statistical test parameter. Subtractions were performed with an automated method and using a reference point-based program in order to test recording reproducibility and image homogeneity, respectively. Paired t-tests revealed that the average SDs obtained by the mechanical fixation method and the optical method were not statistically significantly different neither when applying the automated nor the reference point-based subtraction method (P > 0.05). The SDs increased significantly when the automated method was used compared to the reference point-based method (P = 0.001). In conclusion, the optical method and the mechanical method provided images of similar recording reproducibility and homogeneity.

Clinical and laboratory radiographic caries diagnosis. A study of the same teeth

OBJECTIVE

To compare the diagnostic accuracy of radiographs obtained both in vivo and in vitro of the same teeth for the detection of occlusal and approximal caries.

METHODS

Pre- and post-extraction radiographs were obtained of 130 teeth, mostly third molars. The two sets of radiographs were assessed by four independent observers using a five-level confidence scale. Caries was validated histologically after serial sectioning. A positive diagnosis was defined as caries present in dentine occlusally and in enamel or deeper approximally. The diagnostic accuracy was expressed by ROC curve areas.

RESULTS

For occlusal caries, the average ROC curve area was 0.767 in the in vivo and 0.826 in the in vitro radiographs. The corresponding areas for approximal caries were 0.707 and 0.735, respectively. The differences were not significant (p > 0.05).

CONCLUSION

The outcome of radiographic caries diagnosis in the clinic appeared comparable with that obtained in the laboratory.

In vitro comparison of Kodak Ultra-speed, Ektaspeed, and Ektaspeed Plus, and Agfa M2 Comfort dental x-ray films for the detection of caries

The aim of this study was to compare the diagnostic accuracy of two new dental x-ray films, Kodak Ektaspeed Plus (Plus) and Agfa M2 Comfort (M2), respectively, with the current Kodak Ultra-speed (Ultra) and Ektaspeed (Ekta) films for the detection of caries. A total of 103 occlusal and 224 proximal surfaces were examined independently by three observers. A histologic examination performed after the teeth were sectioned served as the validation method for lesion depth. Receiver operating characteristic curve areas were calculated to express the diagnostic accuracy. In the occlusal surfaces the receiver operating characteristic curve areas ranged from 0.764 (in Ultra films) to 0.800 (in Ekta films). In the proximal surfaces the receiver operating characteristic curve areas ranged from 0.550 (in Ultra films) to 0.696 (in Plus films). No statistically significant differences were found between the different film types.

Radiological modalities in the staging of colorectal tumors: new perspectives for increasing accuracy

The purpose of this study was to evaluate the diagnostic accuracy of contrast-enhanced endorectal MRI for the staging of rectal adenoma versus rectal carcinoma in correlation to findings from biopsy and histopathology. Ten volunteers and 20 patients underwent body-coil and endorectal MRI (1.5T supraconducting unit) using plain, T1-weighted (w) T2-w SE and TSE-w sequences, a dynamic Gd-DTPA enhanced protocol (turboFLASH), and postcontrast T1-w-SE sequences. Histopathological correlation via biopsy (n = 10) and surgical resection (n = 19) were conducted for all patients. An independent, two-observer, reader evaluation was performed and qualitative and quantitative data calculated. In volunteers and all patients endorectal MRI reliably delineated normal wall layers. Rectal adenomas (n = 7) were identified by a visualization of an intact muscularis mucosae, a homogeneous inner structure, and a significant contrast enhancement. T1 carcinomas (n = 4) were best identified in dynamic turboFLASH sequences by delineation of an intact muscularis propria. The visualization of contrast-enhancing tumor tissue was indicative of a T2 carcinoma (n = 4). All T3 (n = 3) and T4 (n = 2) carcinomas were correctly staged on dynamic and static MRI. The endorectal MRI stage agreed with the staging results from pathological study in 16 of 20 (80%) patients. Endorectal surface coil MRI provides reliable data for the preoperative staging and evaluation of rectal lesions.

Accuracy of caries diagnosis in digital images from charge-coupled device and storage phosphor systems: an in vitro study

OBJECTIVES

To evaluate the diagnostic accuracy of carries detection with four intra-oral digital radiographic systems in vitro and to investigate the impact of image compression.

METHODS

116 extracted human premolars and molars mounted three in a line with approximal contacts were radiographed with four digital systems (Digora, RVG, Sens-A-Ray, and Visualix) and imported into a Windows-based program. Sixteen images from each system were compressed (JPEG, irreversible compression). The total of 528 images was assessed by six radiologists using a 5-point confidence scale for the detection of approximal and occlusal caries. Caries was validated histologically. The disease threshold was caries in enamel for approximal surfaces and in dentine for occlusal surfaces.

RESULTS

Mean ROC curve areas for approximal surfaces were 0.611 (DIG), 0.572 (RVG), 0.594 (SAR), and 0.596 (VIX), and for occlusal surfaces 0.794 (DIG), 0.819 (RVG), 0.751 (SAR), and 0.761 (VIX). There were no significant differences between the areas under the ROC curves (p > 0.05); nor were there any significant differences between the compressed and uncompressed images (p > 0.05).

CONCLUSIONS

The four digital systems performed almost equally well for detection of caries in vitro, and compressed images were as accurate as uncompressed.

Stereomicroscopy, film radiography, microradiography and naked-eye inspection of tooth sections as validation for occlusal caries diagnosis

In establishing a trustworthy validation for occlusal caries lesions, various methods have been used after sectioning teeth. The aim of the present study was to compare the accuracy of four such methods: stereomicroscopy (SM), film radiography (FR), microradiography (MR) and naked-eye inspection (NEI) for the detection of caries in occlusal tooth surfaces. Further, the interobserver agreement between three observers' registrations of occlusal caries by these methods was evaluated. The material consisted of 18 unerupted third molars known to be sound with respect to caries, as they were embedded in bone prior to removal, and 20 erupted third molars with an unknown 'true state of disease'. The teeth were serially sectioned, coded and examined blindly for occlusal caries by three independent observers by the four validation methods under study. SM was demonstrated to be the only method by which all observers correctly identified all 18 unerupted teeth as sound, resulting in a specificity of 1.00. By the other three methods, 1 or more of the unerupted teeth were falsely classified as carious. In the erupted teeth, 73, 58, 52 and 32%, respectively, of the teeth were determined carious by SM, MR, NEI and FR. As it was possible by SM to detect caries in nearly three quarters of the erupted teeth and at the same time to identify all unerupted teeth as sound, this method seemed to be the most trustworthy of the validation methods under study.

Clinically undetected dental caries assessed by bitewing screening in children with little caries experience

Following the decline in caries prevalence, it has been questioned whether it is still justifiable to continue the practice of radiographic bitewing screening. This study was undertaken to compare the value of a clinical examination with screening bitewing radiograph in children who had little previous caries experience. One hundred and sixty-eight 14-year-old children participated in the investigation. The children were examined clinically by one of three pedodontists for the presence of 'sound', 'suspect caries', and 'carious' occlusal and approximal tooth surfaces. Bitewing screening radiographs were obtained of all the children prior to the clinical examination. The radiographs were assessed for the presence and extent of occlusal and approximal caries. Radiography detected more than 94% of the total number of reported (clinically and radiographically) caries lesions. 1.2% of the occlusal and 10.2% of the approximal surfaces clinically designated sound were scored as carious by radiography. Of these clinically undetected lesions, 15% were assessed to have penetrated into dentine on the radiographs. Although the number of false-positive radiographic scores could not be ascertained in this study, it is likely that, as the caries prevalence was low, the probability of a false-positive diagnosis would be high. It was therefore concluded that there was no convincing evidence that 14-year-old children with little previous caries experience benefit from a screening bitewing examination.

In vitro comparison of D- and E-speed film radiography, RVG, and visualix digital radiography for the detection of enamel approximal and dentinal occlusal caries lesions

The aims of this study were (1) to compare the accuracy of conventional D- and E-speed film radiography and direct digital radiography using the RadioVisioGraphy and Visualix systems for the detection of enamel approximal caries lesions and (2) to compare the accuracy of D- and E-speed films and the Visualix system for the detection of dentinal occlusal caries lesions. In total, 122 approximal surfaces were examined in vitro by 3 observers and 65 occlusal surfaces by 2 observers. The true caries diagnosis was based on histological assessment of the surfaces after sectioning the teeth. Approximal surfaces were deemed diseased by the presence of a demineralization in enamel, while occlusal surfaces were deemed diseased by the presence of a demineralization into dentine. The diagnostic accuracy for each radiographic method was expressed as a receiver operating characteristic (ROC) curve area. For the approximal surfaces, the areas under the ROC curves ranged from 0.53 (Visualix) to 0.70 (E-speed film). For the occlusal surfaces, the areas ranged from 0.62 (Visualix) to 0.79 (D- and E-speed films). No statistically significant differences between mean ROC curve areas for the radiographic methods were found either for the approximal or for the occlusal surfaces. It was concluded that radiography was of almost no value in the detection of enamel approximal caries lesions, but of some value in the detection of dentinal lesions in occlusal surfaces.

Perception of image quality in direct digital radiography after application of various image treatment filters for detectability of dental disease

This study evaluated dentists' perception of the quality of digitally captured radiographs. Thirty radiographs were taken with the Visualix digital video radiographic system, 10 periapicals for tooth and bone anatomy, 10 periapicals for bone disease and 10 bitewings for dental caries. Three numeric copies were made of each image and treated with three different filters: 'optimize', 'enhance' and 'enhance + smooth', respectively. Four images of the same case were displayed simultaneously in a random sequence on the monitor. Twenty dentists ranked each set of four images on a scale from 1 to 4. In general, most dentists preferred a treated image to the original. The optimized and enhanced images were selected most frequently as first or second choice from the tooth and bone anatomy and bone disease groups. The original image was ranked lowest in more than half (55%) of the series. For the bitewings, the smoothed images were ranked significantly higher. In conclusion, image treatment possibilities should be offered in digital radiography as the majority of dentists preferred a treated image to the original version. The image treatment chosen seemed to be task dependent; less treatment was required to delineate the more subtle tissue differences.

Radiographic screening examination: frequency, equipment, and film in general dental practice in Denmark

The aim of the present study was to evaluate types and frequencies of radiographic screening examinations, and radiographic equipment and film used in general dental practice in Denmark. A questionnaire was mailed to 400 randomly selected dental practitioners. A total of 258 questionnaires were returned, out of which 249 were analyzed. Two-thirds of the respondents performed radiographic screening examinations, of which bitewing-screening was the one most frequently used for first-visit and regular patients. The more recent their graduation year, the more apt were dentists to perform radiographic screening examinations. More than 40% of the dentists had radiographic units operating at a voltage capacity of 60-70 kV, and more than 50% had facilities for automatic or semiautomatic processing. Only one-quarter of the respondents used the Kodak Ektaspeed film (E-speed film). The results show that radiographic procedures and film used in general dental practice are not always in accordance with guidelines and recommendations.

Screening with conventional and digital bite-wing radiography compared to clinical examination alone for caries detection in low-risk children

The study compared conventional and digital bite-wing screening, performed in combination with a clinical examination for caries detection, in 168 14-year-old children with little caries experience. Radiography revealed 2-3 times more carious lesions than did clinical examination. Conventional and digital radiography detected dentinal caries in only 1.6 and 1.1%, respectively, of the clinically sound surfaces. Conventional, as well as digital radiography revealed caries in 7% of occlusal surfaces suspected of caries after a clinical examination. Of the suspected approximal surfaces, conventional radiography found caries in 25%, and digital radiography in 19%. From these results, it may be appropriate to perform radiographic screening in combination with clinical examination when the purpose is to assess caries prevalence, and as a basis for individual treatment decisions, if treatment is offered to surfaces with enamel lesions. However, if treatment is offered only to surfaces with clinically detected lesions and to surfaces with radiographically perceived dentinal lesions, it may not be appropriate to perform radiographic bite-wing screening, as less than 2% of the treatment-demanding surfaces will be overlooked by clinical examination alone. Instead, selective radiography should be conducted of surfaces suspected clinically as being carious.

Digital subtraction radiography for assessment of simulated root resorption cavities. Performance of conventional and reverse contrast modes

A previous study of the sensitivity and accuracy of a standardized radiographic technique for the disclosure of root cavities in a cadaver material indicated that it was not possible to perceive small artificial "resorption" cavities. Using the same material, the aim of the present study was to evaluate whether the use of subtraction radiography would improve the detection of root cavities. In an autopsy material of five mandibular blocks each containing two premolars, small, medium, and large cavities were drilled in the cervical, middle, and apical thirds of the proximal and oral root surfaces. Each jaw block was radiographed before (B) and after (A) cavity preparation with three different exposure times resulting in light, medium, and dark film densities. The radiographs were digitized. Digital subtraction was performed between the A- and B images of varying densities by a computer program developed for dental subtraction radiography. Conventional and reverse contrast modes of the subtraction image were assessed independently by four observers. The results showed small inter- and intraobserver differences in diagnostic accuracy for assessment of total number of root cavities. Original film density did not influence the diagnostic performance in the resulting subtraction image. Contrast mode in the subtraction image influenced diagnostic performance as the majority of observers did best with the reverse contrast mode (p < 0.05). Some of the small root cavities were disclosed by the subtraction technique, but overall accuracy was not increased compared to conventional radiography.

Radiographic detection of occlusal caries in noncavitated teeth. A comparison of conventional film radiographs, digitized film radiographs, and RadioVisioGraphy

The aim of this study was to compare the accuracy of conventional film radiographs, digitized radiographs, and RadioVisioGraphy (RVG) for the detection of dentinal caries in occlusal surfaces of noncavitated extracted teeth. Eighty-one fully erupted extracted third molars were assessed by four observers using five radiographic methods: conventional film radiographs, digitized radiographs with contrast enhancement and with a filtering procedure, and RVG with contrast enhancement and with x function. Scoring criteria were dichotomous. Histologic sections (500 to 600 microns thick) served as the validation criterion. The two digital methods with contrast enhancement tended to perform more accurately than, although not significantly different from, the other three methods (p greater than 0.05). Average likelihood ratios (true positive/false positive) were 4.3 (conventional film radiographs), 4.4 (RVG with contrast enhancement), 3.6 (RVG with x function), 4.9 (digitized radiographs with contrast enhancement), and 3.7 (digitized radiographs with filtering procedure). Observers 1 and 2 (oral radiologists) performed better than observers 3 and 4 with all five methods (p less than 0.005).

Diagnostic value of clinical examination for the identification of children in need of orthodontic treatment compared with clinical examination and screening pantomography

Ninety children in the 5th school grade (means age = 11.9 years) participated in this investigation. As part of the orthodontic screening examination, pantomograms of all children had been performed as a routine procedure. Prior to assessment of the pantomograms each child was assigned to one of the following treatment categories based on clinical examination: -T (no indication for orthodontic treatment), O (observation of dentition development) and +T (indication for orthodontic treatment). Children, in whom clinical symptoms gave rise to a radiographic examination, were selected and their pantomograms assessed. Finally, the pantomograms of all children were interpreted, and the clinically established treatment categories re-evaluated on basis of the findings on the pantomograms. Fifteen children were selected for pantomography, but only one changed treatment category (from O to +T) due to observation of developmentally missing premolars. Three of the children not selected for pantomography changed categories from -T; two to O and one to +T. Clinical examination with selective pantomography was thus able to correctly identify 97 per cent of children in need of immediate orthodontic treatment, while it was able to correctly exclude 94 per cent of the healthy children. On the basis of these results, routine screening pantomography may be omitted.

Longitudinal study of accuracy of clinical examination for detection of permanent tooth aplasia

It was the aim of the present investigation to evaluate the accuracy of clinical examination for the detection of permanent tooth aplasia in the 3rd/4th grade and again 1 yr later and to record the number of children initiating orthodontic treatment in the interval between the two examinations. The validating criterion for tooth aplasia was a panoramic radiograph taken in a routine procedure. 628 children participated in the study. The clinical examinations were performed without knowledge of the radiographic evidence. During the examination children exhibiting symptoms of permanent tooth aplasia were selected for radiography. At both occasions clinical examination was very sensitive for the detection of children with aplasia of permanent incisors (nosological sensitivity = 1.00). It was, however, less sensitive for the detection of children with premolar aplasia (nosological sensitivity = 0.22 at both examinations). The nosological specificity for identification of children without aplasia of incisors and premolars was more than 0.90 at both examinations. Twenty-two children had started orthodontic treatment in the timespan between the two clinical examinations, but only three on the basis of observations on their radiographs alone (aplasia of permanent teeth). The present clinical method would have selected two of these children, thus in only one child postponing panorama screening might have affected treatment prognosis. Between the two examinations all permanent teeth mesial to the permanent second molars had erupted in 181 children who might therefore totally avoid screening radiography.

Accuracy of clinical diagnosis for the detection of dentoalveolar anomalies with panoramic radiography as validating criterion

It is noteworthy that little attention has been paid to the balance between economy, discomfort, and risk to the patient (costs) and the clinical significance (benefit) of panoramic radiography as a routine screening procedure. This study used orthopantomographs to validate clinical detection of dentoalveolar anomalies in young children. It appears that 439 children (67 percent) were exposed without benefit from the radiography.