David Hatcher

Followers

Following

Co-author

Mentions

1,476

Public Views

Fazlollah Ghofranipour

Tarbiat Modares University

Bora Gurel

Kocaeli University

Joachim Quack

Universität Heidelberg

Rita Lucarelli

University of California, Berkeley

Alexandra von Lieven

Universität Münster

Pavel Uspenskij

National Research University Higher School of Economics

DR.ABHITOSH DEBATA

Rajiv Gandhi University of Health Sciences

Mirza Firnanda

Universitas Airlangga

Alan Widgerow

University of California, Irvine

CLEMENT C AZODO

University of Benin

InterestsView All (6)

Uploads

Papers by David Hatcher

Radiation absorbed in maxillofacial imaging with a new dental computed tomography device

Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontology, 2003

Download

The Temporomandibular Joint of the Domestic Dog ( Canis lupus familiaris ) in Health and Disease

Journal of Comparative Pathology, May 1, 2018

Download

Clinical Application of Cone-Beam Computed Tomography of the Rabbit Head: Part 1 – Normal Dentition

Frontiers in Veterinary Science, Oct 17, 2016

Download

Age contributions to airway dimension changes in females

International Journal of Oral and Maxillofacial Surgery, 2017

Download

Consistency and precision of landmark identification in three-dimensional cone beam computed tomography scans

European Journal of Orthodontics, Mar 8, 2011

The purpose of this study was to quantify the consistency and precision of locating three-dimensi... more The purpose of this study was to quantify the consistency and precision of locating three-dimensional (3D) anatomic landmarks. The hypotheses tested are that these landmarks have characteristic and variable error patterns associated with their type and location. The consistency and precision of nine orthodontists identifying 32 landmarks of 19 patients were quantified. The cone beam computed tomography (CBCT) data were acquired using a Hitachi CB MercuRay system. Prior to the study, all examiners were calibrated with respect to the definitions of the landmarks and on the use of the software program (Dolphin) for identifying the landmarks. In addition, a reference guide was provided that had the definitions and sample images of the landmarks. Data were collected in spreadsheets as x, y, and z coordinates and statistically analysed to determine the mean and standard deviation (SD). The mean location for a given landmark on a given patient served as the reference point. The mean of the distances from the reference point was used as the consistency, while the SD of this mean was used as a measure of precision. The error in the x, y, and z planes was calculated in order to determine the specific characteristics of each landmark. The consistency in landmark location and precision did not differ significantly among the nine examiners. Sella turcica was the most consistently (0.50 mm) and most precisely (0.23 mm) identified anatomic landmark. The most inconsistent landmark was porion-right (2.72 mm) and the most imprecise landmark was orbitale-right (1.81 mm). Due to the lack of even distribution of the errors, careful use of these landmarks for analysis purposes is needed.

Download

Knee orthopedics as a template for the temporomandibular joint

Cell Reports Medicine, 2021

Although the knee joint and temporomandibular joint (TMJ) experience similar incidence of cartila... more Although the knee joint and temporomandibular joint (TMJ) experience similar incidence of cartilage ailments, the knee orthopedics field has greater funding and more effective end-stage treatment options. Translational research has resulted in the development of tissue-engineered products for knee cartilage repair, but the same is not true for TMJ cartilages. Here, we examine the anatomy and pathology of the joints, compare current treatments and products for cartilage afflictions, and explore ways to accelerate the TMJ field. We examine disparities, such as a 6-fold higher article count and 2,000-fold higher total joint replacement frequency in the knee compared to the TMJ, despite similarities in osteoarthritis incidence. Using knee orthopedics as a template, basic and translational research will drive the development and implementation of clinical products for the TMJ. With more funding opportunities, training programs, and federal guidance, millions of people afflicted with TMJ disorders could benefit from novel, life-changing therapeutics.

Download

The Diagnostic Yield of Cone-Beam Computed Tomography for Degenerative Changes of the Temporomandibular Joint in Dogs

Frontiers in Veterinary Science, 2021

Degenerative changes of the temporomandibular joint (DTMJ) may be diagnosed via cone - beam compu... more Degenerative changes of the temporomandibular joint (DTMJ) may be diagnosed via cone - beam computed tomography (CBCT). However, despite advancement in CBCT imaging, correlation of DTMJ features identified on CBCT with gross and histological findings is currently limited. This study aimed to correlate CBCT findings of DTMJ of dogs with gross and histopathologic changes. Temporomandibular joints (TMJ) (n = 38) from fresh cadaver heads of asymptomatic dogs (n = 19) were examined radiologically, macroscopically, and microscopically. Association of CBCT - detected DTMJ changes with gross and histological findings were statistically evaluated via kappa statistics and ordinal logistic mixed-effects models. The radiological changes observed on CBCT included joint space narrowing, subchondral/cortical bone changes (i.e., erosions or lysis), osteophytes, and subchondral bone sclerosis. Upon macroscopic evaluation, the majority of examined specimens had mild changes with cartilage defects and...

Download

Intra- and Extra-articular Features of Temporomandibular Joint Ankylosis in the Cat (Felis catus)

Journal of Comparative Pathology, 2020

Temporomandibular joint (TMJ) ankylosis is an uncommon clinical entity in human and veterinary me... more Temporomandibular joint (TMJ) ankylosis is an uncommon clinical entity in human and veterinary medicine. However, the condition is severely debilitating and is life-limiting if not treated. This study sought to characterize the intra-and extra-articular features of naturally occurring TMJ ankylosis in cats. TMJs from clientowned cats (n ¼ 5) that underwent bilateral TMJ gap arthroplasty were examined and compared with TMJs from healthy, age-matched feline cadavers (n ¼ 2) by cone-beam computed tomography (CBCT), microcomputed tomography (mCT) and histologically. Features of bilateral intra-and extra-articular ankylosis compounded by degenerative joint lesions were identified radiographically and histologically in all affected cats. Features of TMJ 'true' ankylosis included variable intracapsular fibro-osseous bridging, degeneration of the disc and the articular surfaces, narrowing of the joint space and flattening of the condylar process of the mandible. Extra-articular features of TMJ ankylosis included periarticular bone formation and fibroosseous bridging between the mandible, zygomatic arch and coronoid process. In addition, subchondral bone loss or sclerosis, irregular and altered joint contours and irregularly increased density of the medullary bone characterized the degenerative changes of the osseous components of the TMJ. Complex radiological and histological features of both ankylosis and pseudoankylosis were identified that clinically manifested in complete inability to open the mouth.

Download

Accuracy and reliability of the expected root position setup on clinical decision making of root position at midtreatment

American Journal of Orthodontics and Dentofacial Orthopedics, 2019

Introduction: Accurate root position is imperative for successful orthodontic treatment that is s... more Introduction: Accurate root position is imperative for successful orthodontic treatment that is stable and functional. Current methods to monitor root position are either inaccurate or use relatively high levels of radiation. A method to generate an expected root position (ERP) setup has been reported to have the potential to accurately evaluate root position with minimal radiation. The purpose of this study was to determine the accuracy and reliability of the clinical decisions made on root position using the ERP setup. Methods: This retrospective study included 10 subjects who had pretreatment and midtreatment cone-beam computed tomography (CBCT) scans and study models. An ERP setup was generated for all patients at midtreatment. Four examiners assessed both the CBCT scan and ERP setup and made clinical decisions regarding the root position with each method. Cohen's kappa was determined to assess intraoperator and intermethod reliability. Sensitivity, specificity, positive predictive value, and negative predictive value were calculated to determine the accuracy of the ERP setup. Results: The kappa values for intraoperator reliability for both the CBCT scan and ERP setup fell within the 0.61-0.80 range. The kappa values for intermethod reliability between the CBCT scan and ERP setup fell within the 0.61-0.80 range for all tooth groups. The sensitivity of the ERP setup ranged from 0.72 to 0.90, specificity ranged from 0.89 to 0.97, positive predictive value ranged from 0.57 to 0.85, and negative predictive value ranged from 0.93 to 0.99. Conclusions: This study demonstrated that the ERP setup, when compared with the gold standard CBCT scan, was accurate and reliable in making clinical decisions regarding root position at midtreatment.

Download

The Diagnostic Yield of Dental Radiography and Cone-Beam Computed Tomography for the Identification of Dentoalveolar Lesions in Cats

Frontiers in Veterinary Science, 2019

The objective of this study was to evaluate the diagnostic yield of dental radiography (DR) and 3... more The objective of this study was to evaluate the diagnostic yield of dental radiography (DR) and 3 cone-beam computed tomography (CBCT) software modules for the identification of 32 pre-defined dentoalveolar lesions in cats. For 5 feline cadaver heads and 22 client-owned cats admitted for evaluation and treatment of dental disease, 32 predefined dentoalveolar lesions were evaluated separately and scored by use of dental radiography and 3 CBCT software modules [multiplanar reconstructions (MPR), tridimensional (3-D) rendering, and reconstructed panoramic views]. A qualitative scoring system was used. Dentoalveolar lesions were grouped into 14 categories for statistical analysis. Point of reference for presence or absence of a dentoalveolar lesion was determined as the method that could be used to clearly identify the disorder as being present. Accuracy, sensitivity, specificity, and positive and negative predictive values were calculated with the McNemar χ 2 test of marginal homogeneity of paired data. When all 3 CBCT software modules were used in combination, the diagnostic yield of CBCT was significantly higher than that of dental radiography for 4 of 14 categories (missing teeth, horizontal bone loss, loss of tooth integrity, feline resorptive lesions), and higher, although not significantly so, for 9 categories (supernumerary teeth, supernumerary roots, abnormally shaped roots, vertical bone loss, buccal bone expansion, periapical disease, inflammatory root resorption, and external replacement root resorption). In conclusion, we found that CBCT provided more clinically relevant detailed information as compared to dental radiography. Therefore, CBCT should be considered better suited for use in diagnosing dentoalveolar lesions in cats.

Download

Evaluation of the diagnostic yield of dental radiography and cone-beam computed tomography for the identification of dental disorders in small to medium-sized brachycephalic dogs

American journal of veterinary research, 2018

OBJECTIVE To evaluate the diagnostic yield of dental radiography (Rad method) and cone-beam CT (C... more OBJECTIVE To evaluate the diagnostic yield of dental radiography (Rad method) and cone-beam CT (CBCT) methods for the identification of 31 predefined dental disorders in brachycephalic dogs. ANIMALS 19 client-owned brachycephalic dogs admitted for evaluation and treatment of dental disease. PROCEDURES 31 predefined dental disorders were evaluated separately and scored by use of dental radiography and 3 CBCT software modules (serial CBCT slices and custom cross sections, tridimensional rendering, and reconstructed panoramic views). A qualitative scoring system was used. Dental disorders were grouped into 10 categories for statistical analysis. Point of reference for presence or absence of a dental disorder was determined as the method that could be used to clearly identify the disorder as being present. Accuracy, sensitivity, specificity, and positive and negative predictive values were calculated with the McNemar χ test of marginal homogeneity of paired data. RESULTS When all 3 CBCT...

Download

Umwandlung dreidimensionaler Cone-Beam CT-Daten in rekonstruierte Fernröntgenseitenaufnahmen

Informationen aus Orthodontie & Kieferorthopädie, 2007

Radiographic Findings in Bisphosphonate-Treated Patients With Stage 0 Disease in the Absence of Bone Exposure

Journal of Oral and Maxillofacial Surgery, 2010

Purpose: Radiographic features in patients with bisphosphonate-related osteonecrosis of the jaw (... more Purpose: Radiographic features in patients with bisphosphonate-related osteonecrosis of the jaw (BRONJ) are well described, but less is known in bisphosphonate-exposed individuals with stage 0 disease (clinical symptoms without exposed necrotic bone) considered at risk for BRONJ. We sought to characterize radiographic findings in a subgroup of patients with concerning clinical symptoms and bisphosphonate exposure to identify imaging features that may presage development of BRONJ. Materials and Methods: A dental symptom survey was returned by 8,572 Kaiser Permanente Health Plan members receiving chronic oral bisphosphonate therapy, and 1,005 patients reporting pertinent dental symptoms or complications after dental procedures were examined. Those without BRONJ but with concerning symptoms were referred for clinical evaluation, including imaging. Among the subset who received maxillofacial imaging, we identified those with stage 0 disease and abnormal radiographic features. Results: There were a total of 30 patients without exposed bone but with concerning symptoms who received maxillofacial imaging (panoramic radiography or computed tomography) in the context of clinical care. Among these 30 patients, 10 had stage 0 disease with similar radiographic features of regional or diffuse osteosclerosis in clinically symptomatic areas, most with extension beyond the involved site. Other findings in these 10 patients included density confluence of cortical and cancellous bone, prominence of the inferior alveolar nerve canal, markedly thickened and sclerotic lamina dura, uniform periradicular radiolucencies, cortical disruption, lack of bone fill after extraction, and a persisting alveolar socket. None had exposed bone develop during 1-year follow-up. The remaining 20 patients had normal or localized radiographic findings consistent with odontogenic pathology. Conclusion: In 10 of 30 symptomatic patients referred for clinical evaluation and imaging, a consistent finding was conspicuous osteosclerosis in clinically symptomatic areas characteristic of stage 0 disease. These data support the need to better understand radiographic features associated with bisphosphonate exposure and to determine whether osteosclerosis is a specific finding indicative of the risk for progression to BRONJ.

Download

Comparison between traditional 2-dimensional cephalometry and a 3-dimensional approach on human dry skulls

American Journal of Orthodontics and Dentofacial Orthopedics, 2004

The cephalogram is the standard used by orthodontists to assess skeletal, dental, and soft tissue... more The cephalogram is the standard used by orthodontists to assess skeletal, dental, and soft tissue relationships. This approach, however, is based on 2-dimensional (2D) views used to analyze 3-dimensional (3D) objects. The purpose of this project was to evaluate and compare a 3D imaging system and traditional 2D cephalometry for accuracy in recording the anatomical truth as defined by physical measurements with a calibrated caliper. Thirteen skeletal landmarks were located by both radiographic methods on 9 dry human skulls. Intraclass correlation (0.995), variance (0.054 mm 2), and standard deviation (SD) (0.237 mm) were averaged over 76 measurements and derived from precision calipers to establish these physical measurements as a reliable gold standard to make comparisons of the 2D and 3D radiographic methods. The results showed great variability of the 2D from the gold standard, with the range varying from Ϫ17.68 mm (underestimation of Gn-Zyg R) to ϩ15.52 mm (overestimation of Zyg L-Zyg R). In contrast, the 3D method (Sculptor, Glendora, Calif) indicated a range of the SD from Ϫ3.99 (underestimation) mm to ϩ2.96 mm (overestimation). The 3D evaluation was much more precise, within approximately 1 mm of the gold standard. These results indicate that, when the actual distance is measured on a human skull in its true dimensions of 3D space, the Sculptor program, by using a 3D method, is more precise and 4 to 5 times more accurate than the 2D approach. Evaluating distances in 3D space with a 2D image grossly exaggerates the true measure and offers a distorted view of craniofacial growth. There is an inherent problem of representing a linear measure occupying a 3D space with a 2D image.

Download

Magnetic resonance spectroscopy of the human masseter muscle in nonbruxing and bruxing subjects

Journal of orofacial pain, 1995

The masseter muscles of six nonbruxing subjects (five men, one woman) and six bruxing subjects (f... more The masseter muscles of six nonbruxing subjects (five men, one woman) and six bruxing subjects (four men, two women) were assessed during chewing by nuclear magnetic resonance spectroscopy (31P-NMR). The NMR spectra were collected on a GE Sigma 1.5T whole body magnet with a double-tuned 31P/1H surface coil. Two-minute trials of rest/chewing/rest were completed three times. Averaged spectra of inorganic phosphate, phosphocreatine, and three adenosine 5' triphosphate peaks were collected in each trial. Bruxing subjects had a lower concentration of total phosphate and phosphocreatine than nonbruxing (control) subjects at rest. Bruxing subjects increased their inorganic phosphate during chewing significantly less than control subjects. The pH levels during rest and during chewing were similar in both controls and bruxers. These preliminary results suggest that bruxing subjects exhibit an altered phosphate metabolism during rest and exhibit a different phosphate metabolism pattern du...

Three-dimensional evaluation of upper airway in patients with different anteroposterior skeletal patterns

Orthodontics & Craniofacial Research, 2013

Obstructive sleep apnea syndrome (OSAS) represents a frequent and common respiratory disease char... more Obstructive sleep apnea syndrome (OSAS) represents a frequent and common respiratory disease characterized by repeated episodes of complete and/or partial obstruction of upper airways during sleep, normally associated with reduction of oxygen saturation in blood. The oral appliances (OAs) are considered to be an effective treatment modality thanks to the upper airway enlargement. Lateral cephalometry has been used for the 2-dimensional evaluation of upper airway form with several limits. We obtained an accurate 3-dimensional (3D) volume analyses with cone beam computed tomography (CBCT) scans to confirm the effects of OA on the upper airway in patients with OSAS. Ten Italian patients with moderate or severe OSA (3 males and 7 females, 53.4 AE 11.3 years of age, and BMI 24.5 AE 2.7), who cannot tolerate continuous positive air pressure therapy and rejected a surgical approach, were treated with non-adjustable customized OAs and evaluated with CBCT and polysomnography. Upper airway form was examined in the presence and absence of OA and the volume was measured and compared in 2 different areas. Specific planes have been considered to match the data and calculate the benefit obtained with therapy. Nine out of ten patients showed an improvement of total upper airway volume and an improvement in apnea-hypopnea index. Volume increased both in the posterior soft palate region and in the posterior tongue region. In the inferior area, we observed greater differences. 3D image reconstruction accurately confirmed morphological changes in the upper airway during OA therapy. The use of this 3D evaluation is expected to improve the results of OA therapy in the future.

Download

Automated landmark identification on cone-beam computed tomography: Accuracy and reliability

The Angle Orthodontist

Objectives To evaluate the accuracy and reliability of a fully automated landmark identification ... more Objectives To evaluate the accuracy and reliability of a fully automated landmark identification (ALI) system as a tool for automatic landmark location compared with human judges. Materials and Methods A total of 100 cone-beam computed tomography (CBCT) images were collected. After the calibration procedure, two human judges identified 53 landmarks in the x, y, and z coordinate planes on CBCTs using Checkpoint Software (Stratovan Corporation, Davis, Calif). The ground truth was created by averaging landmark coordinates identified by two human judges for each landmark. To evaluate the accuracy of ALI, the mean absolute error (mm) at the x, y, and z coordinates and mean error distance (mm) between the human landmark identification and the ALI were determined, and a successful detection rate was calculated. Results Overall, the ALI system was as successful at landmarking as the human judges. The ALI's mean absolute error for all coordinates was 1.57 mm on average. Across all three ...

Download

Novel 3-dimensional analysis to evaluate temporomandibular joint space and shape

American journal of orthodontics and dentofacial orthopedics : official publication of the American Association of Orthodontists, its constituent societies, and the American Board of Orthodontics, 2016

The purpose of this study was to present and validate a novel semiautomated method for 3-dimensio... more The purpose of this study was to present and validate a novel semiautomated method for 3-dimensional evaluation of the temporomandibular joint (TMJ) space and condylar and articular shapes using cone-beam computed tomographic data. The protocol for 3-dimensional analysis with the Checkpoint software (Stratovan, Davis, Calif) was established by analyzing cone-beam computed tomographic images of 14 TMJs representing a range of TMJ shape variations. Upon establishment of the novel method, analysis of 5 TMJs was further repeated by several investigators to assess the reliability of the analysis. Principal components analysis identified 3 key components that characterized how the condylar head shape varied among the 14 TMJs. Principal component analysis allowed determination of the minimum number of landmarks or patch density to define the shape variability in this sample. Average errors of landmark placement ranged from 1.15% to 3.65%, and none of the 121 landmarks showed significant av...