Edwin L. Christiansen

A computed tomographic study of the distances between the maxillary sinus floor and the apices of the maxillary posterior teeth

The mean distance between the apices of the maxillary posterior teeth and the floor of the maxillary sinus was measured from computed tomographic display data from 12 autopsy specimens and 38 human subjects. The distance from these apices to the adjacent lateral bony surfaces was also measured. The apex of the mesiobuccal root of the maxillary second molar was closest to the sinus floor (mean 1.97 mm) but farthest from the buccal bony surface (mean 4.45 mm). The apex of the buccal root of the maxillary first premolar was closest to the adjacent lateral bony surface (mean 1.63 mm) but farthest from the floor of the sinus (mean 7.05 mm).

Intra- and inter-observer variability and accuracy in the determination of linear and angular measurements in computed tomography. An in vitro and in situ study of human mandibles.

The observer variability and accuracy of linear and angular computed tomography (CT) software measurements in the transaxial plane were investigated for the temporomandibular joint with the General Electric 8800 CT/N Scanner. A dried and measured human mandible was embedded in plastic and scanned in vitro. Sixteen observers participated in the study. The following measurements were tested: inter- and extra-condylar distances, transverse condylar dimension, condylar angulation, and the plastic base of the specimen. Three frozen cadaveric heads were similarly scanned and measured in situ. Intra- and inter-observer variabilities were lowest for the specimen base and highest for condylar angulation. Neuroradiologists had the lowest variability as a group, and radiology residents and paramedical personnel had the highest, but the differences were small. No significant difference was found between CT and macroscopic measurement of the mandible. In situ measurement by CT of condyles with structural changes in the transaxial plane was, however, subject to substantial error. It was concluded that transaxial linear measurements of the condylar processes free of significant structural changes had an error and an accuracy well within acceptable limits. The error for angular measurements was significantly greater than the error for linear measurements.

Computed tomography of condylar and articular disk positions within the temporomandibular joint

The computed tomograms of temporomandibular joints in 25 patients (41 joints) were retrospectively evaluated for condylar position and joint space with General Electric computer software. Computed tomography scans of the temporomandibular joint were made in the axial plane with the teeth in centric occlusion, and measurements were made from vertically reformatted images. Interarticular joint spaces were measured anterosuperiorly, superiorly, posterosuperiorly, and posteriorly from the condylar surfaces. This was repeated in five equidistant (3.1 mm) serial sagittal planes across the condyle, beginning and ending, on average, 2.5 mm from the lateral and medial condylar poles. Articular disk positions (anterolateral, anterior, anteromedial, medial, and normal) were correlated with condylar position. Significant differences between disk positions and joint spaces were found most frequently in the anterosuperior and the superior joint interval. When the disk was positioned normally, the anterosuperior joint space was consistent (1.5 to 2.0 mm) across the joint (standard deviation, 0.3 to 0.8 mm). The superior, the posterosuperior, and the posterior joint spaces in the normal joint were greater than the anterosuperior joint space. When the disk was anterior to the condyle, the anterosuperior joint interval was widened. When the disk was medial, the superior joint space was significantly wider than normal across the breadth of the condyle. In those joints in which the disk was anteromedial, there was an absence (0.2 mm) of joint space, and this occurred in all areas of the condyle except in its medial one fourth. In the internally deranged joint, joint space narrowing may be focal in nature.

CT assisted evaluation of variation in length and angulation of the lateral pterygoid muscle and variation in angulation of the medial pterygoid muscle: Mandibular mechanics implications

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Temporomandibular joint pain/dysfunction overlying more insidious diseases: Report of two cases

The attention being directed to the diagnosis and treatment of temporomandibular joint (TMJ) pain and dysfunction is evident from the literature. Because of this greater interest, referral of patients by physicians and dentists to TMJ and orofacial pain clinics is increasing. A potential problem that may arise from a narrow viewpoint of facial pain (concentrating on the TMJ) is the large risk of misdiagnosing the rare patient with a neoplastic tumor. Such a patient presents a serious diagnostic challenge, particularly when clinical signs of TMJ dysfunction also appear. Neoplastic diseases (primary or metastatic to the jaws and TMJ) while relatively rare, do occur.1-3 A report has been documented of one patient being treated for TMJ pain and dysfunction when the underlying cause of the pain was an undiscovered and undiagnosed tumor of life-threatening proportions.4 The purpose of this report is to emphasize the pitfalls that may arise because of a preoccupation with TMJ pain and dysfunction and to illustrate the necessity of an appropriate and adequate clinical and radiographic examination.

Anteriorly displaced temporomandibular joint articular disk

The diagnosis of anterior displacement of a temporomandibular joint articular disk was made with computed tomography and documented with conventional arthrography. We are reporting the case to show the potential value of computed tomography for evaluating problems of the temporomandibular joint. The patient underwent thin-section axial computed tomography with advanced software imaging techniques. The articular disk was evident on the scan. It was anterior to the condyle and inferior to the articular eminence. Further studies are planned to determine whether computed tomography can supplement or possibly supplant conventional arthrography in the diagnosis of soft-tissue disorders of the temporomandibular joint.

Undiagnosed, chronic temporomandibular joint pain: making a case for FDG-PET/CT

A 57-year-old woman was referred to an orofacial pain specialist due to a 4-year history of undiagnosed, chronic pain in the temporomandibular joint (TMJ). She reported alterations in her jaw position associated with marked-to-severe left preauricular pain and masticatory muscle pain (masseter and temporalis). The pain symptoms were described as sharp and stabbing with the patient self-rating her pain at 7 (visual analogue scale 0–10). Symptom triggers included prolonged talking, stress and left-sided chewing. The patient’s medical, family and social history were noncontributory and a history of craniofacial trauma was denied. In addition, no complaints or symptoms were noted in other joints. Radiographic examination using cone beam computed tomography (CBCT) showed minimal change on the mandibular condyle and temporal fossa at initial presentation (Fig. 1). Magnetic resonance imaging (MRI) revealed normal TMJ disc morphology and position. Treatment included physical therapy, occlusal splint prosthesis, muscle relaxants and arthrocentesis with corticosteroids and lidocaine, none of which provided pain relief. Referral was made to a rheumatologist where MRI and radiographic examination of major joints in addition to hands and TMJ revealed normal findings. The following laboratory tests, complete blood counts (CBC), comprehensive metabolic panels, erythrocyte sedimentation rate (ESR), rheumatoid factor (RF) and anti-cyclic citrullinated peptide antibodies, were all within normal ranges. Anti-nuclear antibody (ANA) levels were elevated at 1 : 160 with negative anti-double-stranded DNA, anti-Sj€ ogren’s syndrome B (antiSSB)/La, anti-Smith, anti-ribonucleoprotein with an equivocal anti-SSA/Ro. The rheumatologist’s initial assessment included: