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Biomedical subjects

R G Merrill

Publications and source records attributed to R G Merrill.

At least 19 recordsLinked to original sources
PubMed1999

Noma: report of a case resulting in bony ankylosis of the maxilla and mandible.

Noma, or cancrum oris, has been described as a gangrenous infection of the soft and hard tissues of the oronasal region. Prior to the advent of antibiotics the disease was commonly fatal. Now many survive the acute phase of the disease and present the surgeon with formidable problems of repair. This is a report of a presumed case of noma that resulted in bony ankylosis of the maxilla and mandible. Three-dimensional shaded surface CT reconstruction images were especially useful in demonstrating the architecture of the abnormal bone.

Aged↗
PubMed1992

Histologic study of the fate of autogenous auricular cartilage grafts in the human temporomandibular joint.

Biopsies of 30 autogenous auricular cartilage grafts previously placed in 21 patients with ankylosis and arthropathy of the temporomandibular joint were studied. These joints were reoperated because of persistent pain and limitation of motion. Histologically, all grafts showed viability of the cartilage. Eighteen cartilage grafts placed after Proplast (Vitek, Inc, Houston, TX) or Silastic (Dow Corning, Midland, MI) implants had been removed, all showed foreign-body granuloma with coexistent intact cartilage grafts. This indicated that the autogenous auricular cartilage was resistant to the foreign-body reaction. All cartilage grafts were encased by fibrous tissue. This overgrowth of fibrous tissue may be responsible for the ankylosis. Seven grafts showed cartilaginous proliferation grossly and all showed proliferation histologically. The cartilage proliferation also may contribute to the persistent symptoms and recurrent limitation of joint motion.

Adult↗
PubMed1990

A histologic evaluation of the accuracy of TMJ diagnostic arthroscopy.

Sixty-seven temporomandibular joints with internal derangement were examined with arthroscopy, and synovial biopsies were taken for histologic evaluation. Histologically, in 10 cases, the synovium appeared to be normal in appearance, 24 cases had moderate to severe synovitis, 11 cases showed hyperplastic synovitis, 13 cases showed synovial fibrosis, and foreign body granuloma was found in 9 cases. Correlation between arthroscopic observation and histologic findings disclosed an 89.1% specificity and 100% sensitivity.

Arthroscopy↗
PubMed1989

Central hemangioma of the jaws.

Fifteen cases of central hemangioma of the jaws in 14 patients are reported, and considerations in diagnosis and treatment are discussed. In the management of these tumors, diagnostic considerations are of paramount importance if associated risks are to be minimized while maximizing the chances for a successful outcome. A search of the literature suggests that surgery, either alone or in combination with embolization, remains the treatment of choice for these lesions. All cases in this report were treated surgically without incident and with good results. Of special interest were two cases in which the tumor was removed from the excised mandible, which was then sterilized and used in the immediate reconstruction of the surgical defect.

Adolescent↗
PubMed1988

Secondary closure of oroantral and oronasal fistulas: a modification of existing techniques.

Fifty-three patients, 25 with oroantral and 28 with oronasal fistulas, were treated using a modified technique of peripheral de-epithelialization and overlapping flaps. This technique was used with sliding buccal flaps, palatal rotation flaps, palatal island flaps, tongue flaps, and distant tubed pedicle flaps. The advantage of the flap is that it provides more tissue attachment, which promotes healing and resists the tendency of the flap to return to its original position. A high degree of success can be predicted. Only two failures were observed in 53 cases.

Adolescent↗
PubMed1987

Sliding capsular discopexy.

A surgical technique for inferior repositioning of disk attachments is described. This reattachment of the disk permits much more flexibility and possibly more permanence of the repositioning of the disk and a greater surgical margin of safety by avoiding the disk-bilaminar zone junction. The technique has been used on patients in selected cases in the past 2 years with acceptable clinical results.

Cartilage, Articular↗
PubMed1986

Toxicity of particles emitted from combustion of waste crankcase oil: in vitro and in vivo studies.

The ever-rising cost of energy provides incentives for the utilization of low-cost waste crankcase oil (WCO) for space heating. Although WCO is known to contain toxic heavy metals, the potential health hazards of emissions and waste products resulting from the combustion of WCO are unknown. Thus, the toxicity of the emission particles and waste products from two different types of burners, a Dravo atomizing oil burner (AOB) and a Kroll vaporizing oil burner (VOB), is evaluated using automotive WCO. Samples are characterized by performing elemental analysis and scanning electron microscopy. Both burners emitted fine (less than or equal to 3 microns), respirable particles. The AOB emission particles contained high concentrations of toxic heavy metals, especially Pb, which showed concentrations as high as 7.5%. The VOB retained a significant amount of heavy metals in the burner residue and emitted a much smaller quantity into the air. The toxicity of AOB emission particles, VOB emission particles, and VOB waste residue is evaluated in three bioassay systems, including a rabbit alveolar macrophage (RAM) cytotoxicity in vitro assay, an intratracheal injection infectivity assay, and a peritoneal irritancy test in mice. The emission particles from both burners and leachate from VOB residue produce a dose-related reduction in viability and cellular adenosine triphosphate (ATP) in alveolar macrophages following 20-hr exposure. Acidity of the RAM medium due to the presence of VOB emission particles and waste leachate contributes to its toxicity.(ABSTRACT TRUNCATED AT 250 WORDS)

Air Pollutants↗
PubMed1976

Interdental osteotomy for immediate repositioning of dental-osseous elements.

The treatment of crowded, poorly aligned, and spaced teeth is most commonly accomplished by orthodontic means. Interdental osteotomy offers a method for the immediate repositioning of dental-osseous elements that may serve as an aid to orthodontic treatment or be used as an independent procedure. The history of the procedure, its indications, planning considerations, surgical methods, and case results are presented.

Adult↗