Donald A. Tyndall

Cone-beam CT diagnostic applications: caries, periodontal bone assessment, and endodontic applications.

Cone-beam CT (CBCT) is useful for many maxillofacial applications, such as implant site imaging and diagnosis and treatment planning for orthodontics and craniofacial surgery. Dentoalveolar applications, such as carious lesion detection and characterization, assessment of the three-dimensional nature of periodontal bone topography, and various endodontic applications are less known and not as thoroughly studied. This article explores and assesses in vivo and in vitro efforts to apply CBCT imaging to these more common dentoalveolar tasks. CBCT imaging, like its medical counterpart, can be seen as a highly useful and, in some instances, indispensable part of the dental imaging armamentarium.

Position statement of the American Academy of Oral and Maxillofacial Radiology on selection criteria for the use of radiology in dental implantology with emphasis on cone beam computed tomography

A Position Paper Subcommittee of the American Academy of Oral and Maxillofacial Radiology (AAOMR) reviewed the literature since the original position statement on selection criteria for radiology in dental implantology, published in 2000. All current planar modalities, including intraoral, panoramic, and cephalometric, as well as cone beam computed tomography (CBCT) are discussed, along with radiation dosimetry and anatomy considerations. We provide research-based, consensus-derived clinical guidance for practitioners on the appropriate use of specific imaging modalities in dental implant treatment planning. Specifically, the AAOMR recommends that cross-sectional imaging be used for the assessment of all dental implant sites and that CBCT is the imaging method of choice for gaining this information. This document will be periodically revised to reflect new evidence.

Observer reliability of three-dimensional cephalometric landmark identification on cone-beam computerized tomography

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 <0.45. The systematic difference among observers was greater in X and Z than in Y dimensions, but the maximum mean difference was quite small. 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.

American Academy of Oral and Maxillofacial Radiology executive opinion statement on performing and interpreting diagnostic cone beam computed tomography

The American Academy of Oral and Maxillofacial Radiology (AAOMR) is the professional organization representing oral and maxillofacial radiologists in the United States. The Academy is a nonprofit professional society the primary purposes of which are to advance the science of radiology, improve the quality and access of radiologic services to the patient, and encourage continuing education for oral and maxillofacial radiologists, dentists, and persons practicing oral and maxillofacial imaging in allied professional fields. The AAOMR embraces the introduction of cone beam computed tomography (CBCT) as a major advancement in the imaging armamentarium available to the dental profession. The AAOMR is currently in the process of developing a position paper on appropriate application of CBCT to provide evidence-based guidelines. In the interim, the Executive Committee (EC) of the AAOMR considers it necessary to provide an opinion document addressing the principles of application of CBCT as it relates to acquisition and interpretation of maxillofacial imaging in dental practice.

A comparison of kodak ektaspeed plus film and the siemens sidexis digital imaging system for caries detection using receiver operating characteristic analysis

OBJECTIVE To evaluate the accuracy of proximal caries detection comparing enhanced and unenhanced Siemens Sidexis CCD-based digital images with Ektaspeed Plus films utilizing receiver operating characteristic analysis. STUDY DESIGN Sixty extracted teeth (24 posterior and 36 anterior) were imaged under identical standardized geometric and exposure conditions. Six observers, using a 5-point confidence scale, rated 120 proximal surfaces for the presence or absence of carious lesions by means of three image modalities: (1) observer enhanced and (2) unenhanced Sidexis displays, and (3) Ektaspeed Plus films. The ground truth was determined by microscopic analysis of ground sections. Receiver operating characteristic curves were generated with calculated areas (AZ) analyzed with analysis of variance for effect of reader, reading, and modality. RESULTS Analysis of variance demonstrated significant differences among readers, readings and modalities (mean square values of 0.012, 0.005, 0.004, F ratios of 13.604, 5.329, 5.100; p = values of 0.001, 0.043, and 0.030, respectively). Post-hoc paired comparisons of modalities using Tukeys statistic demonstrated that only film and enhanced Sidexis images were different from each other (p = 0.024). AZ scores were 0.7650, 0.7499, and 0.8008 respectively, for unenhanced Sidexis, enhanced Sidexis, and Ektaspeed Plus film. CONCLUSION Unenhanced digital Sidexis images were equivalent to film for the detection of proximal caries in this in vitro study. Observer enhanced Sidexis images exhibited a statistically significant lower diagnostic accuracy than the unenhanced digital and film images.

Dental anomalies associated with amelogenesis imperfecta: A radiographic assessment

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).

Digital subtraction radiography for detecting cortical and cancellous bone changes in the periapical region

Previous studies have found that bony lesions cannot be visualized on conventional radiographs unless there is cortical plate involvement. The aim of this project was to compare the sensitivity of digital subtraction to conventional radiography for detecting periapical changes in cortical and cancellous bone. Using a long source-to-object X-ray technique and E-speed film, serial radiographs of a dry skull mandible were obtained. Two bone lesions per radiograph were simulated using #1 to 8 round burs. Conventional and digitally subtracted images were evaluated for lesion presence by a board of reviewers. The results demonstrated greater sensitivity scores for digitally subtracted images in identifying cortical and cancellous bone changes. The lower limit of detection was less for digitally subtracted images in cortical and cancellous bone as well.

Assessment of external root resorption using digital subtraction radiography

Digital subtraction radiography was investigated for its capability to detect and quantify experimentally produced external root resorptive defects in teeth. Using a long source to object X-ray technique and E-speed film, serial radiographs of teeth with artificial lesions in a dry human skull (soft tissue simulated) were obtained. Receiver operating characteristic analysis was used to evaluate the diagnostic performance for each imaging system (conventional versus subtraction). To explore the quantitative assessment potential of digital subtraction radiography, images were produced after sequential demineralization by HCl. The acid solution was analyzed for calcium concentration by atomic absorption spectrophotometry. Three-dimensional histogram quantification for each subtracted image was performed. In overall performance for detecting experimentally produced external root resorption, digital subtraction radiography was found to be significantly superior to conventional radiography. In addition, digital subtraction radiography can provide quantification of experimentally produced external root resorptive defects.

Head Orientation in CBCT-generated Cephalograms

OBJECTIVE To determine the reliability of obtaining two-dimensional cephalometric measurements using two virtual head orientations from cone-beam computed tomography (CBCT) models. MATERIALS AND METHODS CBCT scans of 12 patients (6 class II and 6 class III) were randomly selected from a pool of 159 patients. An orthodontist, a dental radiologist, and a third-year dental student independently oriented CBCT three-dimensional (3D) renderings in either visual natural head position (simulated NHP) or 3D intracranial reference planes (3D IRP). Each observer created and digitized four CBCT-generated lateral cephalograms per patient, two using simulated NHP and two using 3D IRP at intervals of at least 3 days. Mixed-effects analysis of variance was used to calculate intraclass correlation coefficients (ICCs) and to test the difference between the orientations for each measure. RESULTS ICC indicated good reliability both within each head orientation and between orientations. Of the 50 measurements, the reliability coefficients were > or =0.9 for 45 measurements obtained with 3D IRP orientation and 36 measurements with simulated NHP. The difference in mean values of the two orientations exceeded 2 mm or 2 degrees for 14 (28%) of the measurements. CONCLUSIONS The reliability of both virtual head orientations was acceptable, although the percentage of measurements with ICC >0.9 was greater for 3D IRP. This may reflect the ease of using the guide planes to position the head in the 3D IRP during the simulation process.

Incidental findings from cone beam computed tomography of the maxillofacial region: a descriptive retrospective study

OBJECTIVE To evaluate the type and prevalence of incidental findings from cone beam computed tomography (CBCT) of the maxillofacial region. Findings are divided into those that require (i) intervention/referral, (ii) monitoring, and (iii) no further evaluation. METHODS Three hundred consecutive CBCT scans conducted in the University of North Carolina School of Dentistry Oral and Maxillofacial Radiology Clinic from January 1 to August 31, 2008 were retrospectively reviewed. Findings were categorized into airway, soft tissue calcifications, bone, temporomandibular joint (TMJ), endodontic, dental developmental, and pathological findings. RESULTS A total of 272 scans revealed 881 incidental findings (3.2 findings/scan). The most prevalent was airway findings (35%) followed by soft tissue calcifications (20%), bone (17.5%), TMJ (15.4%), endodontic (11.3%), dental developmental (0.7%), and pathological (0.1%). 16.1% required intervention/referral, 15.6% required monitoring, and the remainder (68.3%) required neither. CONCLUSION This study underscores the need to thoroughly examine all CBCT volumes for clinically significant findings within and beyond the region of interest.