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Objective To evaluate reliability in 3-dimensional (3D) landmark identification using cone-beam computerized tomography (CBCT). Study design Twelve presurgery CBCTs were randomly selected from 159 orthognathic surgery patients. Three observers independently repeated 3 times the identification of 30 landmarks in the sagittal, coronal, and axial slices. A mixed-effects analysis of variance model estimated the intraclass correlations (ICC) and assessed systematic bias. Results The ICC was >0.9 for 86% of intraobserver assessments and 66% of interobserver assessments. Only 1% of intraobserver and 3% of interobserver coefficients were Conclusion Overall, the intra- and interobserver reliability was excellent. Three-dimensional landmark identification using CBCT can offer consistent and reproducible data if a protocol for operator training and calibration is followed. This is particularly important for landmarks not easily specified in all 3 planes of space.

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 α = 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.

Objective. The objective of this study was to compare the diagnostic efficacy of tuned-aperture computed tomography (TACT) and conventional film for the detection of simulated periodontal defects. Study Design. Periodontal defects were created in 15 premolar-molar interproximal sites selected from 8 cadaver jaw segments. Ten observers viewed 45 image pairs (baseline and follow up) in 4 TACT modalities and film to assess the presence of defect. The TACT modalities were 1st and 2nd generation prototype systems (TACT-1 and TACT-2) with circular (C) and random (R) distribution patterns of source projection (TACT-1C, TACT-1R, TACT-2C, TACT-2R). Observer performance and related factors were analyzed by using receiver operating characteristic and analysis of variance. Results. Mean Az values were 0.64 for film, 0.74 for TACT-1C, 0.82 for TACT-1R, 0.64 for TACT-2C, and 0.69 for TACT-2R. TACT-1R was significantly better than film (P

Amelogenesis imperfecta, a group of hereditary conditions primarily affecting the enamel, has been associated with dental anomalies, including taurodontism, congenitally missing teeth, delayed eruption, crown resorption, and abnormal enamel density. The purpose of this study was to assess the prevalence of these anomalies in an amelogenesis imperfecta population. The study group consisted of members of 9 unrelated families--22 family members with amelogenesis imperfecta and 13 unaffected family members. Panoramic radiographs were evaluated for taurodontism, congenitally missing teeth, delayed tooth eruption, pathologic dental resorption, pulp calcification, and radiographic enamel density. The prevalence of taurodontism was similar in people with amelogenesis imperfecta and normal people; all of the remaining parameters were more commonly observed in people with amelogenesis imperfecta. The radiographic enamel density was quantitatively reduced in teeth affected by amelogenesis imperfecta in comparison with teeth with normal enamel. These findings suggest that some of the features associated with amelogenesis imperfecta result from abnormal enamel formation (eg, decreased enamel density, crown resorption) whereas others may occur as a result of expression of the genetic mutation in cells other than ameloblasts (eg, abnormal eruption, pulp calcification).

Objective. The purpose of this study was to compare the diagnostic performance of conventional digital images and tuned aperture computed tomography (TACT) slices in caries detection through use of cathode-ray tube monitor and laptop displays. Study design. Forty-two extracted posterior teeth were mounted and imaged with a direct digital radiography system. Conventional digital bitewing projections and TACT slices were acquired. Images were viewed on a high-resolution cathode-ray tube monitor and on an active-matrix laptop display. Eight observers assessed caries status of occlusal and proximal surfaces of the teeth using all combinations of image and display modality. Observers’ assessments were compared with the results of histologic examination of tooth sections. Possible differences in receiver operating characteristic curve areas among displays, image modalities, observers, and surfaces were analyzed by means of analysis of variance. Results. There was no statistically significant difference between the diagnostic performances provided by the cathode-ray tube monitor and laptop displays in caries detection ( P = .588). In addition, the performances of digital images and TACT slices were not significantly different ( P = .843). Conclusions. Modern active-matrix laptop displays provide diagnostic quality for caries detection comparable to that obtainable with cathode-ray tube monitors. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1999;88:234-8)

Objective. The objective of this study was to evaluate the accuracy of alveolar crestal bone detection in a comparison of unenhanced and enhanced Sidexis (Siemens Medical Systems, Inc., Bensheim, Germany) digital images with Ektaspeed Plus (Eastman Kodak, Rochester, N.Y.) films by means of receiver operating characteristic analysis. Study Design. More than 100 proximal and furcal areas in the anterior and posterior areas of the mandible and maxilla of each of three tissue-equivalent human skull phantoms were imaged with film, direct digital images, and contrast- and brightness-enhanced digital images. Alveolar crest status was assessed by a consensus panel of three experts who used the Delphi method and evaluated information from all of the imaging modalities concurrently. Five observers assessed all images for the presence or absence of crestal bone loss using a five-point confidence scale. Receiver operating characteristic curves were generated, and calculated areas (Az) were analyzed by means of analysis of variance. Results. The expert panel determined that of 106 crestal areas, 48 were disease free and 58 exhibited bone loss greater than 2 mm apical to the cemento-enamel junction. Analysis of variance of observer Az scores showed significant differences among readers (p < 0.001) and among readings (p = 0.027), but not among modalities (p = 0.435). Mean Az values for the different modalities were as follows: Sidexis, 0.70; enhanced Sidexis, 0.71; Ektaspeed Plus films, 0.735. Conclusion. The Sidexis digital imaging system was not significantly different from Ektaspeed Plus film for crestal bone evaluation in this in vitro study.

This in vitro investigation compares biplanar (sagittal and coronal) temporomandibular joint images produced by multidirectional tomographic and panoramic techniques for diagnostic accuracy in the detection of simulated degenerative lesions. A series of dentin chips placed at four locations on the head of a temporomandibular joint condyle in a dried human skull were imaged with tomographic and panoramic modalities. Equal numbers of images with and without chips were scored by four examiners with the use of confidence levels for presence or absence of the lesion. To assess intra-examiner reliability, each examiner viewed one of the modalities twice. Responses were assessed by generating receiver operating characteristic curves and analyzing the area (Az) under the curves with analysis of variation methods. Biplanar tomography provided significantly more accurate assessment of condylar lesions than biplanar panoramic images (p=0.007). No statistical difference by location (p=0.592) was found. The effects of observer and repeated observation were marginally significant at p=0.046 and p=0.030, respectively.

Immediate access to off-site expert diagnostic consultants regarding unusual radiographic findings or radiographic quality assurance issues could be a current problem for private dental practitioners. Teleradiology, a system for transmitting radiographic images, offers a potential solution to this problem. Although much research has been done to evaluate feasibility and utilization of teleradiology systems in medical imaging, little research on dental applications has been performed. In this investigation 47 panoramic films with an equal distribution of images with intraosseous jaw lesions and no disease were viewed by a panel of observers with teleradiology and conventional viewing methods. The teleradiology system consisted of an analog video-based system simulating remote radiographic consultation between a general dentist and a dental imaging specialist. Conventional viewing consisted of traditional viewbox methods. Observers were asked to identify the presence or absence of 24 intraosseous lesions and to determine their locations. No statistically significant differences in modalities or observers were identified between methods at the 0.05 level. The results indicate that viewing intraosseous lesions of video-based panoramic images is equal to conventional light box viewing.

EARLY DETECTION AND QUANTITATIVE ASSESSMENT OF APICAL ROOT RESORPTION USING CROWNROOT RATIO AND TUNED-APERTURE COMPUTED TOMOGRAPHY (TACT). Andre Mol, Julie H. Mol, Onanong Chai-u-dom, and Donald A. Tyndall, University of North Carolina, Chapel Hill, NC, and Chulalongkorn University, Bangkok, Thailand Background. Apical root resorption (ARR) is a complication of orthodontic treatment without clear causative factors. The relationship between causative factors and ARR may be obscured by inaccuracies in current methods of detection and quantification. Twodimensional imaging, lack of image standardization, as well as orthodontic tooth movement and remodeling of the surrounding tissues all pose considerable challenges. Objective. The purpose of this study was to develop and test a tuned-aperture computed tomography (TACT) application and to assess the validity of the crown-root ratio (CRR) method for the detection and quantification of small oblique apical root resorption lesions. Methods and materials. A registered (R) and a nonregistered (NR) version of TACT were tested. In TACT-R, the detector moved with the tooth through mechanical standardization. TACT-NR allowed the tooth to move independently of the detector. Ten basis images with a maximum angular disparity of 20° were used. Oblique slicing of TACT-NR follow-up stacks was required for registration with baseline stacks. A slice shifting algorithm was applied to prevent drifting of cross-talk shadows. Twenty extracted maxillary incisors placed in a widened alveolus of a maxillary jaw segment served as test and control sites. Baseline images were acquired without lesions. Follow-up images were acquired with and without lesions. Lesions were created by cutting an oblique buccolingual segment of the root just below the apex. Teeth were moved between baseline and follow-up (rotation and torque), and a bone-putty mixture was used to simulate remodeling of the surrounding bone. CRR, TACT-R, and TACT-NR were tested by 6 radiologists using ROC-analysis. CRR and TACT-R were also tested for their quantitative ability. Results. Low Az-values were obtained for CRR (0.68; SD .09), TACT-R (0.64; SD .09), and TACT-NR (0.60; SD .09). Differences between modalities were not statistically significant (ANOVA: P .05). Lesion quantification was poor for both CRR (R .03) and TACT-R (R .13). Conclusions. Crown-root ratio and TACT are not valid for the detection and quantification of small oblique apical root resorption lesions. Imaging techniques with greater angular disparity between basis images reduce cross-talk effects and are likely to improve performance.