Efficacy of identifying maxillofacial lesions in cone-beam computed tomographs by orthodontists and orthodontic residents with third-party software.

INTRODUCTION: The purpose of this study was to determine the ability of orthodontists and orthodontic residents to identify nonorthodontic incidental findings and false positives in cone-beam computed tomography scans. METHODS: Two groups of 10 cone-beam computed tomography scans containing equal numbers of scans with no, 1, or several abnormal nonorthodontic lesions were selected from a database. Eight orthodontists and 8 orthodontic residents screened the 2 groups of scans before and after a basic cone-beam computed tomography training course. The paired t test was used for statistical analyses. RESULTS: In the initial screening, the orthodontists and residents correctly identified 41.1% of the lesions. This lesion-detection rate improved significantly to a mean of 56.7% after the training course (P <0.0005). In parallel with these findings, the mean percentage of correctly identified extragnathic lesions improved significantly, from 22% to 48% (P <0.0005), and correctly identified temporomandibular joint lesions improved from 20% to 55% (P = 0.01) after the training. In contrast, the rate of correctly identified dentomaxillofacial lesions remained largely unchanged before and after the training. Both groups of evaluators had approximately 5 false positives per 10 scans before training and demonstrated significant decreases in false positives after training. CONCLUSIONS: Relative to known error rates in medical radiology, both groups of evaluators had high error rates for missed lesions and false positives before and after training. Given these findings and since the most frequent cause of medical radiology malpractice litigation is due to missed lesions, it is recommended that an appropriately trained radiologist should be involved in reading and interpreting cone-beam computed tomography scans.

Cross-sectional analysis of the mandibular lingual concavity using cone beam computed tomography.

OBJECTIVES: To study the prevalence and the degree of lingual concavity in the edentulous first molar region from cone beam computed tomography (CBCT) scans of the mandibles. MATERIAL AND METHODS: Qualified cross-sectional images in mandibular first molar edentulous region taken from CBCT were selected. The mandible morphology 2 mm above the inferior alveolar canal (IAC) was classified into the convex (C), parallel (P) and undercut (U) type, based on the presence of lingual concavity and the shape of alveolar ridge. The prevalence of each group was determined. Subsequently, the lingual concavity characters, including the depth, the angulation and the vertical location were determined by the measurements of selected anatomic landmarks. RESULTS: One hundred and three subjects (mean age 51 with a range of 23.7-70.4 years) were studied. The U type was the most prevalent, accounting for 66% of the study population. The mean undercut depth and angulation at the level 2 mm above IAC were on average 2.4 mm and 57.7°. The mean vertical distances from the most prominent point (P) of the lingual concavity to the cemento-enamel junction of second premolar and the inferior border of the mandible were 11.7 and 14.9 mm, respectively. CONCLUSIONS: The anatomic location and the degree of the lingual concavity presented in this article add more information in implant treatment planning in the mandibular first molar edentulous region.

Effect of ridge morphology on guided bone regeneration outcome: conventional tomographic study.

BACKGROUND: This study retrospectively analyzed conventional tomograms to estimate the prognostic value of the cross-sectional ridge morphology on the clinical outcome of guided bone regeneration (GBR). METHODS: Presurgical conventional tomograms of 23 single-implant sites were analyzed retrospectively in 20 patients. All sites had a non-space-making buccal dehiscence defect associated with the subsequently placed dental implant. Simultaneous GBR procedures were performed, and 6-month clinical outcomes were assessed. Measurements at baseline and at the 6-month reentry included defect height (from smooth-rough junction to the most apical part of the defect) and horizontal bone gain at three locations (smooth-rough junction, middle, and most apical portion of the defect). All measurements were taken from a reference template. Tomographic parameters included the implant-associated ridge angle and width measured at 6 mm below the alveolar crest and at the most apical point of the implant. Implant exposure and the presence of the barrier membrane were controlled for during statistical analyses. RESULTS: The presurgical ridge angle had a significant negative correlation with the percentage of defect height reduction (r = -0.621; P = 0.002) and horizontal bone gain (r = -0.469; P = 0.024). This difference remained significant even after controlling for implant/membrane exposure (P = 0.001 and P = 0.019, respectively). A statistically and clinically greater percentage of defect height reduction was observed for ridge angles <28 degrees (P = 0.023). Ridge width did not have a significant effect on the regenerative outcome. CONCLUSION: Cross-sectional presurgical ridge angles may have prognostic value in estimating the outcome of simultaneous GBR.

A clinical trial of the Nomad portable X-ray unit.

OBJECTIVES: To compare image quality of intraoral radiographs made with the Nomad portable X-ray unit (Aribex, Inc.) and with a wall-mounted dental X-ray machine in a clinical setting. METHODS AND MATERIALS: Twelve patients requiring a full-mouth radiographic series for diagnostic purposes were recruited for the study, in which half of the radiographs (one side selected randomly) were made with the Nomad and half with a wall-mounted dental X-ray machine. Each individual image was evaluated independently by three reviewers for diagnostic utility and quality, using a three-point scale: 2 = perfect radiograph; 1 = acceptable for diagnostic purposes despite a small error; 0 = unacceptable. A total score was derived for each of the 220 images, each of the 12 patients, and the study population as a whole. RESULTS: The combined quality scores of the three reviewers for each set of radiographs ranged from 22-60 for the Nomad and 21-55 for the control units. Median scores were 33 for the Nomad and 33.5 for the control. The maximum possible score was nine films/half mouth x two points for perfect film x three reviewers = 54 (maximum 66 for 11 films). Three of the films, all on the same patient in a wheelchair, showed motion artifact (two with Nomad, one with control). DISCUSSION: Image quality for radiographs taken with the Nomad and a wall-mounted X-ray machine appears to be similar in a variety of clinical situations. Motion artifact is not a significant issue with the Nomad.

Radiographic detection of approximal caries: a comparison between senior dental students and senior dental hygiene students.

PURPOSE: Dental hygienists do not legally (or definitively) diagnose caries, but they often are responsible for preliminary interpretation of bitewing (BW) radiographs taken during prophylaxis appointments. Given this custom of practice, it is important to understand whether there is a difference between the capabilities of dental hygienists and dentists in interpreting BWs based on education and clinical experience. This study compared proximal carious lesion classification from BWs by senior dental students and senior dental hygiene students. METHODS AND MATERIALS: Volunteers (40 dental [D] and 54 dental hygiene [DH] students) classified proximal carious lesions from BWs of 96 extracted teeth, which were mounted in wax to simulate quadrants of the mouth. A soft tissue equivalent was placed in front of the mounted teeth before x-ray exposure. Films were developed automatically and mounted into six sets point scale. The teeth were sectioned vertically and evaluated clinically at 5x magnification with an explorer. The "gold standard" of carious lesion classification was then compared to the students' classifications. RESULTS: All students detected 54% of the carious lesions and correctly identified lack of caries 80.5% of the time. There were no differences between the two groups of students in terms of sensitivity, but dental students showed higher specificity (p = 0.0006). CONCLUSION: Permitting dental hygienists to make preliminary interpretations of caries from BWs in the dental office appears to be an acceptable practice.

Diagnosis of non-dental conditions. Carotid artery calcifications on panoramic radiographs identify patients at risk for stroke.

BACKGROUND: The oral and maxillofacial manifestations of some occult systemic disorders may be identified during the provision of dental care. Medical conditions so identified should be referred to a physician for confirmation by appropriate test and indicated therapy. Atherosclerosis at the bifurcation of the carotid artery is a common cause of stroke, and, when such lesions are calcified, they may easily be identified on a panoramic radiograph since the carotid bifurcation lies within the field of a properly performed X-ray. LITERATURE REVIEWED: To examine the degree to which this finding is recognized by the dental community, the authors conducted a PubMed review to find publications that detailed the identification of carotid artery calcifications on panoramic radiographs. RESULTS: Between 1981-2003, there were 39 peer-reviewed dental manuscripts and 29 pertinent abstracts reporting the observation of incidental carotid calcifications visible on routine panoramic radiographs. These studies documented a 3% to 5% prevalence of carotid artery calcifications in the general dental population, with higher percentages occurring in patients having medical illnesses associated with advanced atherosclerosis. PRACTICE IMPLICATIONS: The widespread recognition that calcifications seen in the region of the carotid bifurcation can identify a population at increased risk of stroke supports the practice of routinely examining this area during review of panoramic radiographs. Since a panoramic radiograph is often obtained for dental reasons, in many instances, further examination of the area of the carotid bifurcation is essentially cost-free, and can serve to prolong lives and bring significant savings in overall health care costs by assisting in the prevention of critical events such as strokes.

Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) for Clinical and Research Applications: recommendations of the International RDC/TMD Consortium Network* and Orofacial Pain Special Interest Group†.

AIMS: The original Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) Axis I diagnostic algorithms have been demonstrated to be reliable. However, the Validation Project determined that the RDC/TMD Axis I validity was below the target sensitivity of ≥ 0.70 and specificity of ≥ 0.95. Consequently, these empirical results supported the development of revised RDC/TMD Axis I diagnostic algorithms that were subsequently demonstrated to be valid for the most common pain-related TMD and for one temporomandibular joint (TMJ) intra-articular disorder. The original RDC/TMD Axis II instruments were shown to be both reliable and valid. Working from these findings and revisions, two international consensus workshops were convened, from which recommendations were obtained for the finalization of new Axis I diagnostic algorithms and new Axis II instruments. METHODS: Through a series of workshops and symposia, a panel of clinical and basic science pain experts modified the revised RDC/TMD Axis I algorithms by using comprehensive searches of published TMD diagnostic literature followed by review and consensus via a formal structured process. The panel's recommendations for further revision of the Axis I diagnostic algorithms were assessed for validity by using the Validation Project's data set, and for reliability by using newly collected data from the ongoing TMJ Impact Project-the follow-up study to the Validation Project. New Axis II instruments were identified through a comprehensive search of the literature providing valid instruments that, relative to the RDC/TMD, are shorter in length, are available in the public domain, and currently are being used in medical settings. RESULTS: The newly recommended Diagnostic Criteria for TMD (DC/TMD) Axis I protocol includes both a valid screener for detecting any pain-related TMD as well as valid diagnostic criteria for differentiating the most common pain-related TMD (sensitivity ≥ 0.86, specificity ≥ 0.98) and for one intra-articular disorder (sensitivity of 0.80 and specificity of 0.97). Diagnostic criteria for other common intra-articular disorders lack adequate validity for clinical diagnoses but can be used for screening purposes. Inter-examiner reliability for the clinical assessment associated with the validated DC/TMD criteria for pain-related TMD is excellent (kappa ≥ 0.85). Finally, a comprehensive classification system that includes both the common and less common TMD is also presented. The Axis II protocol retains selected original RDC/TMD screening instruments augmented with new instruments to assess jaw function as well as behavioral and additional psychosocial factors. The Axis II protocol is divided into screening and comprehensive self report instrument sets. The screening instruments' 41 questions assess pain intensity, pain-related disability, psychological distress, jaw functional limitations, and parafunctional behaviors, and a pain drawing is used to assess locations of pain. The comprehensive instruments, composed of 81 questions, assess in further detail jaw functional limitations and psychological distress as well as additional constructs of anxiety and presence of comorbid pain conditions. CONCLUSION: The recommended evidence-based new DC/TMD protocol is appropriate for use in both clinical and research settings. More comprehensive instruments augment short and simple screening instruments for Axis I and Axis II. These validated instruments allow for identification of patients with a range of simple to complex TMD presentations.

Anatomical variations of trabecular bone structure in intraoral radiographs using fractal and particles count analyses.

PURPOSE: This study was performed to evaluate possible variations in maxillary and mandibular bone texture of normal population using the fractal analysis, particles count, and area fraction in intraoral radiographs. MATERIALS AND METHODS: Periapical radiographs of patients who had full mouth intraoral radiographs were collected. Regions of interest (100×100 pixels) were located between the teeth of the maxillary anterior, premolar, and molar area, as well as the mandibular anterior, premolar, and molar areas. The fractal dimension (FD) was calculated by using the box counting method. The particle count (PC) and area fraction (AF) analyses were also performed. RESULTS: There was no significant difference in the FD values among the different groups of age, gender, upper, and lower jaws. The mean FD value was 1.49±0.01. The mean PC ranged from 44 to 54, and the mean AF ranged from 10.92 to 11.85. The values of FD, PC, and AF were significantly correlated with each other except for the upper molar area. CONCLUSION: According to the results, patients with normal trabecular pattern showed a FD of approximately 1.5. Based on these results, further investigation would be recommended if the FD value of patient significantly differenct from this number, since the alteration of this value indicates microstructural modification of trabecular pattern of the jaws. Additionally, with periapical radiographs, simple and cost-effective, PC and AF could be used to assess the deviation from the normal.

From 2D to 3D: an algorithm to derive normal values for 3-dimensional computerized assessment.

OBJECTIVE: To test the accuracy of a mathematical model (algorithm) that corrects measurements made on conventional lateral head films to corresponding dimensions observed in a cone beam computed tomography (CBCT) scan in human subjects. MATERIALS AND METHODS: Thirteen subjects had lateral cephalograms taken with a conventional cephalometric machine as well as a CBCT scan. Measurements of midface length, mandibular length, and lower anterior face height (LAFH) from both examinations were calculated. Two other groups of measurements were derived mathematically from the dimensions directly quantified on the lateral cephalogram: the magnification correction group and the algorithm correction group. The data were analyzed statistically, using repeated measures analysis of variance (ANOVA). RESULTS: All measurements from the lateral cephalogram were significantly different from the corresponding measurements derived from the CBCT. Simply taking into account the image magnification did not correct the 2-dimensional (2D) linear measurement obtained from a conventional cephalogram into a 3-dimensional (3D) linear measurement made on a CBCT scan, unless the structures from which the distance will be measured are located on the midsagittal plane. When the algorithm was used to correct the 2D measurements, however, there were no statistically significant differences between the CBCT group and the algorithm group. CONCLUSIONS: Using the mathematical formula presented herein, 2D cephalometric measurements from landmarks both on and off the midsagittal plane can be corrected into a 3D CBCT measurement with accuracy. By applying this algorithm to other existing cephalometric longitudinal growth studies, control groups and standards for CBCT images could be derived without exposing untreated subjects to radiation.

Anterior mandibular lingual salivary gland defect: a report of a case diagnosed with cone-beam computed tomography and magnetic resonance imaging.

Anterior mandibular lingual salivary gland defects are rare. They may be evident on routine radiographic exam. Because the differential diagnosis can be exhaustive, differential interpretation and diagnosis are crucial. A case of large bilateral radiolucent lesions of the anterior mandible that was an anterior mandibular salivary gland defect is reported in a young female. This lesion was initially visualized on a panoramic radiograph. Further evaluation was undertaken with dental cone-beam computed tomography. Confirmation of bilateral anterior mandibular lingual salivary gland defects was made using magnetic resonance imaging, negating the need for surgical biopsy.

Comparison of linear tomography and direct ridge mapping for the determination of edentulous ridge dimensions in human cadavers.

OBJECTIVE: The purpose of this study was to compare the accuracy of linear tomography (LT) and direct ridge mapping (RM) for determining alveolar ridge dimensions. STUDY DESIGN: One site in the posterior mandible was selected for evaluation in each of 5 cadaver heads. Vacuum-formed stents made from models of the cadaver ridges were used to identify 3 sets of measurement points for each specimen: coronal (intersection of coronal and middle third of ridge), middle (intersection of middle and apical third), and apical (base of vestibule). The imaging stent contained 2-mm metal balls at each point, while the RM stent had holes drilled at corresponding locations. Linear tomograms and periapical radiographs (PA) were taken of the selected sites. RM measurements were made with calipers. Five blinded examiners measured ridge width at the designated measurement points with both LT and RM as well as distance from the ridge crest to mandibular canal (using PAs for RM group). Mandibles were then sectioned and an independent examiner made direct measurements (DM). MANOVA was used to determine whether LT and RM differed significantly from DM. RESULTS: There were no significant differences between LT and RM for ridge width measurements. However, both techniques underestimated ridge dimensions compared to DM ( P < .05). Measurement of mandibular canal height was accurate when determined by periapical radiographs but not by LT. CONCLUSION: Neither LT nor RM proved to be completely accurate in determining ridge width in the posterior mandible.