Aditya Tadinada

Diagnostic accuracy of 2 cone-beam computed tomography protocols for detecting arthritic changes in temporomandibular joints.

INTRODUCTION The temporomandibular joint (TMJ) is a complex joint that often develops degenerative joint disease. Clinical examination alone cannot usually diagnose this accurately, and a radiographic examination complements and aids in diagnosis and treatment. The osseous components of the TMJ complex are best imaged using computed tomography. The evolution of cone-beam computed tomography (CBCT) offers a low radiation dose and a high spatial resolution alternative and is becoming the imaging modality of choice for the TMJ. To further reduce the dose and yet not compromise the diagnostic task at hand, some alternative rotation acquisition protocols are available but have not been adequately evaluated. The aim of this study was to evaluate the diagnostic efficacy of 2 CBCT acquisition protocols to detect degenerative changes associated with the TMJ complex. METHODS Thirty-four TMJs, from 17 dry human skulls, were obtained from the anatomy department at the School of Dental Medicine of the University of Connecticut. The sample consisted of complete dentate and partially dentate skulls with no identifiable markers such as age, sex, or ethnicity. Small and large lesions simulating early and established arthritic changes were created on the mandibular condyle. Each defect was randomly created on the medial pole, articulating surface, or lateral pole. After simulating the articular disc with rubber dam material, the condyle and the glenoid fossa were articulated and positioned in place by a rubber band. The skulls were scanned by using an Accuitomo CBCT scanner (J. Morita Corp, Kyoto, Japan) with 180° and 360° rotation protocols. Two operators scored the lesions and compared the results to the gold standard, which was the master list of where the lesions were made on the condyles. RESULTS On the 102 randomly selected sites, 39 large and 33 small lesions were made, and the rest of the sites had no lesions. The detection rates for areas with large lesions and areas with no lesions were 100% between the examiners. However, of the 33 small lesions, each examiner was able to identify 32 of them with the 360° scans: a 97.4% detection rate when compared with the gold standard. With the 180° scan, 94.9% of the small lesions were detected when compared with the gold standard, and 96.9% were detected with the 360° scan. The overall interexaminer reliability was over 90% for both imaging protocols (Cronbachs alpha, 92.4% for 180° and 97% for 360°). CONCLUSIONS Based on the results of this study, the 180° CBCT acquisition protocol can detect small and large arthritic lesions with high reliability and is comparable with the 360° spin acquisition.

Radiographic evaluation of the maxillary sinus prior to dental implant therapy: A comparison between two-dimensional and three-dimensional radiographic imaging

Purpose This study was performed to evaluate the diagnostic efficacy of panoramic radiography and cone-beam computed tomography (CBCT) in detecting sinus pathology. Materials and Methods This study was based on a retrospective evaluation of patients who had undergone both a panoramic radiograph and a CBCT exam. A total of 100 maxillary sinuses were evaluated. Four examiners with various levels of expertise evaluated the images using a five-point scoring system. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the diagnostic efficacy of the two modalities. The image analysis was repeated twice, with at least two weeks between the evaluation sessions. Interobserver reliability was assessed using Cronbachs alpha, and intraobserver reliability was assessed using Cohens kappa. Results Maxillary sinus pathology was detected in 72% of the patients. High interobserver and intraobserver reliability were observed for both imaging modalities and among the four examiners. Statistical analyses using ROC curves demonstrated that the CBCT images had a larger area under the curve (0.940) than the panoramic radiographs (0.579). Conclusion Three-dimensional evaluation of the sinus with CBCT was significantly more reliable in detecting pathology than panoramic imaging.

Cellular and Matrix Response of the Mandibular Condylar Cartilage to Botulinum Toxin

Objectives To evaluate the cellular and matrix effects of botulinum toxin type A (Botox) on mandibular condylar cartilage (MCC) and subchondral bone. Materials and Methods Botox (0.3 unit) was injected into the right masseter of 5-week-old transgenic mice (Col10a1-RFPcherry) at day 1. Left side masseter was used as intra-animal control. The following bone labels were intraperitoneally injected: calcein at day 7, alizarin red at day 14 and calcein at day 21. In addition, EdU was injected 48 and 24 hours before sacrifice. Mice were sacrificed 30 days after Botox injection. Experimental and control side mandibles were dissected and examined by x-ray imaging and micro-CT. Subsequently, MCC along with the subchondral bone was sectioned and stained with tartrate resistant acid phosphatase (TRAP), EdU, TUNEL, alkaline phosphatase, toluidine blue and safranin O. In addition, we performed immunohistochemistry for pSMAD and VEGF. Results Bone volume fraction, tissue density and trabecular thickness were significantly decreased on the right side of the subchondral bone and mineralized cartilage (Botox was injected) when compared to the left side. There was no significant difference in the mandibular length and condylar head length; however, the condylar width was significantly decreased after Botox injection. Our histology showed decreased numbers of Col10a1 expressing cells, decreased cell proliferation and increased cell apoptosis in the subchondral bone and mandibular condylar cartilage, decreased TRAP activity and mineralization of Botox injected side cartilage and subchondral bone. Furthermore, we observed reduced proteoglycan and glycosaminoglycan distribution and decreased expression of pSMAD 1/5/8 and VEGF in the MCC of the Botox injected side in comparison to control side. Conclusion Injection of Botox in masseter muscle leads to decreased mineralization and matrix deposition, reduced chondrocyte proliferation and differentiation and increased cell apoptosis in the MCC and subchondral bone.

Classification and volumetric analysis of temporal bone pneumatization using cone beam computed tomography.

OBJECTIVE This study performed volumetric analysis and classified different repeated patterns of temporal bone pneumatization in adults using cone beam computed tomography (CBCT) scans. STUDY DESIGN A total of 155 temporal bones were retrospectively evaluated from 78 patients with no radiographic evidence of pathology. Two reference structures were used to classify temporal bone pneumatization into 3 groups. Volumetric analysis of the pneumatization was performed using a window thresholding procedure on multiplanar CBCT images. Correlation between direct communication of peritubal cells with the eustachian tube and the degree of pneumatization was also assessed. RESULTS Using 2 reference structures, pneumatization pattern in the temporal bone can be classified into 3 groups. Statistically significant differences were present in their mean volumes between 3 groups. Statistically significant correlation was found between degree of pneumatization and presence of peritubal cells associated with ET. CONCLUSIONS This study showed that CBCT can be effectively used for imaging temporal bone air cavities and for volumetric assessment.

Evaluation of linear measurements of implant sites based on head orientation during acquisition: An ex vivo study using cone-beam computed tomography.

Purpose This study evaluated the effect of various head orientations during cone-beam computed tomography (CBCT) image acquisition on linear measurements of potential implant sites. Materials and Methods Six dry human skulls with a total of 28 implant sites were evaluated for seven different head orientations. The scans were acquired using a Hitachi CB-MercuRay CBCT machine. The scanned volumes were reconstructed. Horizontal and vertical measurements were made and were compared to measurements made after simulating the head position to corrected head angulations. Data was analyzed using a two-way ANOVA test. Results Statistical analysis revealed a significant interaction between the mean errors in vertical measurements with a marked difference observed at the extension head position (P<0.05). Statistical analysis failed to yield any significant interaction between the mean errors in horizontal measurements at various head positions. Conclusion Head orientation could significantly affect the vertical measurements in CBCT scans. The main head position influencing the measurements is extension.

Arrested pneumatization of the sphenoid sinus mimicking intraosseous lesions of the skull base

Arrested pneumatization of the sphenoid sinus is a developmental variant that is not always well recognized and is often confused with other pathologies associated with the skull base. This report describes the case of a patient referred for cone-beam computed tomography (CBCT) imaging for dental implant therapy. CBCT demonstrated a well-defined incidental lesion in the left sphenoid sinus with soft tissue-like density and sclerotic borders with internal curvilinear opacifications. The differential diagnoses included intraosseous lipoma, arrested pneumatization of the sphenoid sinus, chondrosarcoma, chondroid chordoma, and ossifying fibroma. The radiographic diagnosis of arrested pneumatization was based on the location of the lesion, its well-defined nature, the presence of internal opacifications, and lack of expansion. Gray-scale CBCT imaging of the area demonstrated values similar to fatty tissue. This case highlighted the fact that benign developmental variants associated with the skull base share similar radiographic features with more serious pathological entities.

Evaluation of alveolar bone dimensions in unilateral palatally impacted canine: a cone-beam computed tomographic analyses.

INTRODUCTION The purpose of this study was to evaluate the alveolar bone dimensions and arch perimeter discrepancy in unilateral palatally impacted canines. METHODS This retrospective split-mouth study reviewed 207 cone-beam computed tomography (CBCT) scans of patients with unilateral or bilateral impacted canines referred for orthodontic treatment. Out of 207 CBCT scans, only 39 scans in which canines were unilaterally palatally impacted were approved for the study based on our inclusion and exclusion criteria. Two fiducial lines were used to orient the examiners and standardize the measurements. Arch perimeter, buccopalatal (BP) width, and alveolar height were measured both on the impacted and non-impacted side. Two different examiners measured all the parameters. A one-sample Kolmogorov-Smirnov test was used to examine normality of distribution of outcomes. Wilcoxon Signed Rank tests were used for comparing arch width and alveolar bone height between the impacted and non-impacted sides. For arch perimeter, the paired-sample t-test was used. RESULTS The arch perimeter, BP width, and alveolar bone height was significantly decreased on the impacted side (P < 0.05). The mean arch perimeter on the impacted side was 41.7 ± 2.5mm compared to 43.5 ± 2.37 on the non-impacted side. Similarly, BP width and alveolar bone height on the impacted side was 6.87 ± 1.08 mm and 18.12 ± 2.28 mm, respectively, whereas on the non-impacted side was 8.70 ± 1.13 mm and 19.49 ± 2.09 mm, respectively. CONCLUSION There was a significant decrease in the arch perimeter and alveolar bone dimensions (BP width and alveolar bone height) on the impacted side.

CBCT evaluation of buccal bone regeneration in postmenopausal women with and without osteopenia or osteoporosis undergoing dental implant therapy

STATEMENT OF PROBLEM Because alveolar bone augmentation in women with osteoporosis/osteopenia has an uncertain prognosis, objective and reliable methods should be used to study standard surgical approaches. PURPOSE The purpose of this clinical study was to evaluate bone regeneration 9 months after bone augmentation and implant placement in postmenopausal women with different levels of systemic bone health by using cone beam computed tomography (CBCT) and to test proof of concept for this measurement approach. MATERIAL AND METHODS A subset of 14 participants was analyzed in a best practice study of postmenopausal women receiving dental implants and simultaneous horizontal ridge augmentation. Women were categorized as osteopenic/osteoporotic or normal based on the results of preoperative dual-energy x-ray absorptiometry. All implant study sites received a particulate graft and/or buccal plate expansion. The study sites were evaluated with CBCT preoperatively, immediately postoperatively, and 9 months postoperatively. Nonparametric statistics were used for all analyses. The related samples Wilcoxon signed rank test was used to assess the differences in bone width between time points (α=.05 for all tests). RESULTS After 9 months, 13 out of 14 participants showed increased bone width compared to the preoperative baseline measurements. The increase was statistically significant for the participants with osteoporosis/osteopenia (P=.007), but not for those with normal bone health (P=.066). The CBCT scans showed that mineralized tissue buccal to the implant surface had the radiographic appearance of mature bone. CONCLUSIONS CBCT showed evidence of bone regeneration, with an increase in alveolar ridge width in postmenopausal osteopenic/osteoporotic women subsequent to surgical reconstruction.

The reliability of tablet computers in depicting maxillofacial radiographic landmarks.

Purpose This study was performed to evaluate the reliability of the identification of anatomical landmarks in panoramic and lateral cephalometric radiographs on a standard medical grade picture archiving communication system (PACS) monitor and a tablet computer (iPad 5). Materials and Methods A total of 1000 radiographs, including 500 panoramic and 500 lateral cephalometric radiographs, were retrieved from the de-identified dataset of the archive of the Section of Oral and Maxillofacial Radiology of the University Of Connecticut School Of Dental Medicine. Major radiographic anatomical landmarks were independently reviewed by two examiners on both displays. The examiners initially reviewed ten panoramic and ten lateral cephalometric radiographs using each imaging system, in order to verify interoperator agreement in landmark identification. The images were scored on a four-point scale reflecting the diagnostic image quality and exposure level of the images. Results Statistical analysis showed no significant difference between the two displays regarding the visibility and clarity of the landmarks in either the panoramic or cephalometric radiographs. Conclusion Tablet computers can reliably show anatomical landmarks in panoramic and lateral cephalometric radiographs.

Dental Anomalies Associated with Craniometaphyseal Dysplasia

Craniometaphyseal dysplasia (CMD) is a rare genetic disorder encompassing hyperostosis of craniofacial bones and metaphyseal widening of tubular bones. Dental abnormalities are features of CMD that have been little discussed in the literature. We performed dentofacial examination of patients with CMD and evaluated consequences of orthodontic movement in a mouse model carrying a CMD knock-in (KI) mutation (Phe377del) in the Ank gene. All patients have a history of delayed eruption of permanent teeth. Analysis of data obtained by cone-beam computed tomography showed significant bucco-lingual expansion of jawbones, more pronounced in mandibles than in maxillae. There was no measurable increase in bone density compared with that in unaffected individuals. Orthodontic cephalometric analysis showed that patients with CMD tend to have a short anterior cranial base, short upper facial height, and short maxillary length. Microcomputed tomography (micro-CT) analysis in homozygous AnkKI/KI mice, a model for CMD, showed that molars can be moved by orthodontic force without ankylosis, however, at a slower rate compared with those in wild-type Ank+/+ mice (p < .05). Histological analysis of molars in AnkKI/KI mice revealed decreased numbers of TRAP+ osteoclasts on the bone surface of pressure sides. Based on these findings, recommendations for the dental treatment of patients with CMD are provided.