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Biomedical subjects

S L Brooks

Publications and source records attributed to S L Brooks.

At least 37 records · Page 2Linked to original sources
PubMed1995

Gradient-echo MR imaging of the temporomandibular joint: diagnostic pitfall caused by the superficial temporal artery.

OBJECTIVE: In routine MR imaging of the temporomandibular joints, a low-signal structure posterosuperior to the mandibular condyle is occasionally seen on the two-dimensional gradient-echo sequence. The structure is ovoid and may have a higher-signal core, simulating a loose body within the joint. We undertook a clinical and cadaveric study to determine the cause of this finding. MATERIALS AND METHODS: In a clinical study, we reviewed the MR images of 100 temporomandibular joints. We scored each joint for the presence and appearance of a low-signal structure posterosuperior to the mandibular condyle: type 1 was ovoid with a low-signal rim and a higher-signal core, type 2 was ovoid with uniformly low signal, type 3 was a low-signal structure inseparable from the posterior wall of the glenoid fossa, and type 4 was normal. Using this scoring system, we determined the appearance and frequency of the finding on two-dimensional gradient-echo, T1-, T2-, and proton density-weighted images. To determine the cause of the finding, we correlated the imaging and anatomic findings in a cadaveric specimen. RESULTS: Of the 100 MR images of joints reviewed, 22 showed a type 1 structure, 24 a type 2 structure, 11 a type 3 structure, and 43 were normal. The finding was seen only on the two-dimensional gradient-echo sequences, never on the spin-echo sequences. Correlation between the imaging and anatomic findings in the cadaveric specimen showed that the finding was caused by the superficial temporal artery. The variability in its appearance is thought to result from the complex manifestations of flowing blood within this artery. CONCLUSION: The finding posterosuperior to the mandibular condyle seen on two-dimensional gradient-echo MR images is a flow phenomenon within the superficial temporal artery. Recognition of the nature of this finding will avoid mistaking it for disease, such as an intraarticular loose body.

Adult↗
PubMed1993

Validation of a specific selection criterion for dental periapical radiography.

It has been recommended that the prescription of dental radiographic examinations be based on a series of selection criteria. This study evaluated the usefulness of the presence of a large or deep restoration as an indicator for the need for a radiographic examination. Patients in need of routine examinations were questioned regarding pain in restored teeth. The radiographs of 2269 restored teeth in 209 patients were evaluated for depth of restoration and presence or absence of periapical pathosis. Another 1306 nonrestored teeth in 100 patients were evaluated similarly. There was an association between pain and periapical pathosis and between depth of restoration and periapical pathosis (p < 0.001 in each case). Radiographic yield for positive apical findings was low in restored teeth, especially when the restoration was shallow. The radiographic yield may be increased if other factors such as pain or integrity of the restoration are used to help make the decision regarding the need for radiographs.

Chi-Square Distribution↗
PubMed1993

Temporomandibular joint: value of coronal MR images.

To evaluate the use of coronal magnetic resonance (MR) imaging in assessment of disk position in the temporomandibular joint (TMJ), sagittal and coronal 1.5-T MR images were obtained of 158 TMJs in 79 patients. From the sagittal images, medial or lateral displacement was suspected in 24 joints. Displacement could be confirmed from coronal images in 21 joints but could not be confirmed in three. In 18 other joints, the coronal images revealed a lateral or medial displacement that was not evident on sagittal images. In seven of these 18, displacement was purely lateral or purely medial, whereas the other 11 had a combination of anterior and lateral or medial displacement. On the basis of only sagittal images, the seven with pure displacement would have been diagnosed as normal. Use of the coronal plane added diagnostic information to that obtained with sagittal imaging and may increase diagnostic accuracy. Coronal images are therefore recommended as a supplement to sagittal images in MR imaging evaluation of the TMJ.

Adolescent↗
PubMed1993

Computed tomography.

Although CT scanning has been available for less than 20 years, it has made a major impact on the practice of dentistry, particularly in oral and maxillofacial surgery, in the diagnosis and management of a wide variety of oral lesions. The use of computers to reconstruct x-ray attenuation data into an image allows the clinician to view pathology from many different perspectives, unobstructed by other anatomic structures, and to adjust contrast to concentrate on the soft-tissue and hard-tissue pathology in turn. Advances in computer software already allow three-dimensional visualization of pathology and anatomy, but additional refinements in this technology still are expected.

Humans↗
PubMed1993

Advances in diagnostic imaging in dentistry.

Advances in optical and x-ray imaging will affect dramatically the practice of dentistry in the next decade. "Hard copy" of these images will be on thermographic paper from videoprinters as well as x-ray film. Reconstruction of images in both (two and three dimensions) will allow better visualization of disease processes and allow quantification of disease changes over time, thus assisting the treatment planning decisions of the dentist and improving patient care. Some of these innovations are here, others are in the research and development stage. All dentists eventually will use these techniques routinely.

Diagnosis, Oral↗
PubMed1992

Temporomandibular joint: surgically created disk displacement causes arthrosis in the rabbit.

To document a causal relationship between temporomandibular joint disk displacement and arthrosis, the disk was surgically displaced in one temporomandibular joint in each of three rabbits. The rabbits were sacrificed after 4 weeks and the mandibular condyles were studied radiographically and histologically. All three joints that underwent disk displacement had radiographic and histologic evidence of arthrosis, which included erosion of the bone, irregularity and fissure formation of the articular soft tissue cover, disruption of the subchondral layer of cartilage cells, and chondrocyte proliferation. No radiographic or histologic changes occurred in the joints that were untouched. The results suggest that surgically created disk displacement can cause arthrosis in the temporomandibular joint of the rabbit.

Animals↗
PubMed1992

Temporomandibular joint disk displacement without reduction. Treatment with flat occlusal splint versus no treatment.

A flat occlusal splint has been extensively used in the treatment of patients with temporomandibular joint disk displacement without reduction, but no studies with untreated controls have assessed its effect. We randomly assigned 51 patients with temporomandibular joint pain and arthrographically verified disk displacement without reduction to be treated with a flat occlusal splint or to serve as untreated control subjects in a 12-month clinical trial. Pain symptoms disappeared in about one third of the patients in each group. Another third of the patients in the control group improved. Sixteen percent of the patients in the control group and 40% of the patients treated with a flat occlusal splint were worse at the end than at the beginning of the study. Joint pain and muscle tenderness decreased more frequently in the nontreatment controls than in the treatment group. A statistically significant benefit of a flat occlusal splint over nontreatment control subjects could not be identified in this study of patients with painful disk displacement without reduction. The use of a flat occlusal splint in this patient group should therefore be reconsidered.

Adolescent↗
PubMed1992

Accuracy of clinical diagnosis for TMJ internal derangement and arthrosis.

This study investigated the accuracy of clinical examination in determining the status of the temporomandibular joint with respect to internal derangement and arthrosis. A series of 110 patients was given standard clinical examinations followed by bilateral imaging with arthrography and/or magnetic resonance imaging. There was agreement between the clinical diagnosis and the imaging finding in 95 joints (43%). In the other 125 joints (57%), the clinical diagnosis did not agree with imaging findings. There were false-positive clinical diagnoses in 39 joints and false-negative clinical diagnoses in 31 joints. In the other 55 joints the clinical diagnosis correctly indicated that the joint was abnormal but was incorrect about the stage of abnormality. On the basis of the overall diagnostic accuracy of 43%, it was concluded that a clinical examination is not reliable for determining the status of the joint in patients with signs and symptoms of temporomandibular joint internal derangement.

Adolescent↗
PubMed1992

Oral radiographs in the detection of early signs of osteoporosis.

A study was conducted to determine whether radiographic changes could be detected in the mandible of patients with mild-to-moderate postmenopausal osteoporosis and whether these changes could be used as a diagnostic tool to differentiate normal from osteoporotic patients. Subjects were classified as either osteoporotic (21) or normal (14) on the basis of bone density measurements of the lumbar spine and femoral neck, as determined by dual-photon absorptiometry. Mandibular bone density measurements were made on panoramic and periapical radiographs and expressed in terms of millimeters of aluminum equivalent. Thickness of the cortex at the angle of the mandible, sinus floor, and lamina dura of the tooth socket was also measured. There were no significant differences in any of the mandibular measurements between the normal and osteoporotic subjects. Whereas the skeletal bone measurements were correlated with each other, there was no correlation between skeletal and mandibular bone measurements. Women with mild-to-moderate osteoporosis could not be distinguished from women with normal bone density with the method described in this article.

Bone Density↗
PubMed1992

Prevalence of osseous changes in the temporomandibular joint of asymptomatic persons without internal derangement.

There is a controversy in the literature regarding the prevalence of osseous changes in the temporomandibular joint (TMJ) of asymptomatic persons. Using cephalometrically corrected tomograms, we assessed one TMJ of each of 34 asymptomatic persons who had no arthrographic or magnetic resonance imaging evidence of internal derangement. Minimal flattening of the condyle or articular eminence was seen in 12 joints (35%). More advanced osseous changes such as erosion, osteophytosis, or sclerosis were not seen in any joint. The findings suggest that generally no osseous changes occur in the TMJ in asymptomatic persons without internal derangement. When osseous changes occur, they are confined to minimal flattenings. Minimal flattening is probably of no clinical significance because the persons were asymptomatic, and arthrography and magnetic resonance imaging showed no evidence of abnormalities in the soft tissues.

Adolescent↗
PubMed1992

Compliance of Michigan dentists with radiographic safety recommendations.

We surveyed a random sample of 398 Michigan dentists in private practice to determine their compliance with the American Dental Association Council's recommendations for radiographic equipment and techniques. The response rate was 67% of the questionnaires delivered successfully. The majority of dentists use only D-speed film (73%) and round collimation of the x-ray beam (90%). Only 5% have an x-ray machine equipped with a rectangular collimator and 18% have at least one machine with a pointed cone. Leaded apron use is almost universal, but only 49% of the dentists use cervical collars in addition to the apron. The majority of dentists surveyed do not comply with the American Dental Association Council's recommendations on film speed, collimation, and use of leaded cervical collar. Using effective dose equivalents determined by Gibbs et al. for a variety of radiographic techniques, we estimate that an eight-fold reduction in radiation dose could be achieved without eliminating a single radiograph if all dentists used E-speed film and collimation of the beam to the size of the film.

Attitude of Health Personnel↗
PubMed1992

Temporomandibular joint sounds: correlation to joint structure in fresh autopsy specimens.

In an attempt to better understand the cause of different types of temporomandibular joint (TMJ) sounds, we recorded joint sounds from 27 fresh autopsy specimens, displayed the time frequency distribution of the sound as a three-dimensional graph, and correlated the sound character to morphologic observations at subsequent dissection. Eleven joints elicited sounds, and 16 joints were silent. All joints with sounds had different degrees of intraarticular changes. These ranged from disk displacement with reduction to displacement without reduction and arthrosis of the articular surfaces. Reciprocal clicking occurred both in joints with disk displacement with and without reduction, as well as in joints with arthrotic changes. Crepitation only occurred in joints with arthrosis and perforation. The sample was too small to demonstrate any statistically significant association between the joint sound classified as clicking or crepitation and joint structure types of joint pathosis in this small sample. A high frequency component to the sound appeared to be associated with arthrosis of the articular surfaces. It was concluded that joint sounds indicate joint abnormality but that the absence of joint sound does not exclude intraarticular pathosis.

Aged↗
PubMed1992

Temporomandibular joint: relationship between MR evidence of effusion and the presence of pain and disk displacement.

OBJECTIVE: The purpose of this study was to correlate MR evidence of joint effusion in the temporomandibular joint with symptoms of joint pain and the presence of disk displacement and arthrosis. SUBJECTS AND METHODS: The temporomandibular joints of 379 patients with clinical symptoms of temporomandibular joint disorders and 11 asymptomatic volunteers were imaged bilaterally. Sagittal and coronal proton density-weighted and T2-weighted images were obtained. Imaging findings of joint effusion were correlated with the presence of disk displacement and arthrosis and the symptom of pain. RESULTS: MR showed effusion in 7% of the joints with normal superior disk position, 40% of the joints with disk displacement with reduction, 50% of the joints with disk displacement without reduction, and 27% of the joints with arthrosis. Two of the control subjects had disk displacement with reduction; MR did not show joint effusion in any of the control subjects. A strong association was seen between joint effusion and joint pain. Joint effusion was seen in 46% of the joints on the more painful side and in 13% of the joints on the less painful side. CONCLUSION: The results show that temporomandibular joint effusions primarily occur in joints with disk displacement and are strongly associated with joint pain.

Humans↗
PubMed1991

Biosensors for process control.

Biosensors have been extensively studied during the last 20 years, and a myriad of laboratory biosensors have been developed. Improvements are required in biosensor design and performance before they become widely accepted in industrial process monitoring. However, as the biotechnology industry expands, biosensors may become more acceptable because, despite their limitations, they are the only devices capable of delivering the information required.

Biosensing Techniques↗
PubMed1990

Anti-inflammatory glucocorticoids inhibit the induction by endotoxin of nitric oxide synthase in the lung, liver and aorta of the rat.

The induction by endotoxin of Ca2(+)-independent nitric oxide (NO) synthase in the lung and liver of the rat was prevented by the glucocorticoids dexamethasone and cortisol but not by progesterone. The activity of the constitutive Ca2(+)-dependent NO synthase in the brain and the aorta was not affected by treatment with either endotoxin or glucocorticoids. In the aorta a Ca2(+)-independent NO synthase was also found following endotoxin treatment of rats, and this induction was likewise prevented by dexamethasone. The Ca2(+)-dependent NO synthase in the aorta was located in the vascular endothelium, whereas the Ca2(+)-independent enzyme was predominantly located in the vascular smooth muscle layer. Inhibition of induction of the Ca2(+)-independent NO synthase in vivo may underlie some of the physiological and pharmacological effects of the anti-inflammatory glucocorticoids.

Amino Acid Oxidoreductases↗
PubMed1989

The appearance of mental foramina on panoramic and periapical radiographs. II. Experimental evaluation.

The image of the mental foramen was studied on panoramic and periapical radiographs taken on four dry skulls with a variety of vertical and horizontal angulations, skull positions, and exposure times. It was found that any change in exposure conditions affected both the type of appearance (continuous, separated, diffuse, or unidentified) and the relative vertical position of the foramen. The radiographic position agreed with the actual position less than half the time regardless of technique, although the apparent diameter of the foramen was close to the true diameter.

Adult↗