Biomedical subjects
Publications and source records attributed to J N Kent.
Most condylar fractures of the mandible may be treated by closed reduction and appropriate physiotherapy. Some, however, absolutely should be opened and reduced anatomically; with others, good arguments for open reduction may be offered. This article reviews the possible indications for open reduction and presents an approach that conceals the scar.
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An approach to correction of nasomaxillary dysplasia is described. Where midfacial hypoplasia is managed by surgical anteropositioning of the affected skeletal parts, this technique permits management of the associated nasal dysmorphia as well. The one-stage correction is performed with the midfacial skeleton entirely degloved, under direct vision. Details are described, and diagnostic and treatment considerations of two patients are given.
The clinical performance of LTI carbon, carbon-coated aluminum oxide, and uncoated aluminum oxide blade-type dental implants was studied in baboons. The objective of the study was to determine the effect that implant material elastic modulus and surface composition have on implant performance. Clinical parameters of mobility, sulcus depth, soft tissue characteristics, and radiographic appearance were used in the evaluation. The implants were placed in healed extraction sites in adult female baboons and were used as a distal abutment for a three-unit fixed gold prosthesis. The restorations were allowed to assume normal occlusal function and were left in situ for a period of two years. The radiographic and sulcus depth measurements appeared inferior for the LTI carbon implants and best for the carbon-coated aluminum oxide implants. No differences in mobility or soft tissue characteristics were noted for the three implant systems. Two implants both in the same animal--one LTI carbon and one uncoated aluminum oxide--were definite clinical failures. The results of the study indicate that an elastic modulus mismatch between implant and bone is not an a priori cause of implant failure and that the implant surface composition had little apparent effect on the clinical and radiographic performance of these implant materials.
Comparison of tissue ingrowth density values for Proplast I and its aluminum oxide analog, Proplast II, when implanted on the primate infraorbital rim and inferior border of the mandible, showed no difference between the two test materials. A similar comparison of local cellular response ratings showed slightly less response to Proplast II. Microscopic and clinical examination did not otherwise reveal any significant differences in biologic reaction to these materials.
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The presurgical evaluation, surgical treatment, and postoperative plan for benign maxillary tumors have been reviewed. Each tumor deserves individual consideration on the basis of its behavior and size. Treatment must also be suited to the particular case. Cases have been reviewed to demonstrate treatment.
A one-year prospective study of mandibular fractures that included 253 consecutive patients with 422 mandibular fractures was completed at Charity Hospital, New Orleans. Nine major categories were studied. Patients with multiple mandibular fractures seemed to have a fracture pattern. Complications associated with mandibular fractures are influenced more by location of the fracture or fractures and the cause than by a few days' delay in treatment, the specific technique in treatment, or extraction of teeth associated with the fracture. Thorough knowledge of occlusion and the masticatory apparatus is paramount in successful treatment.
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Presurgical infusion of Proplast (Vitek, Inc., Houston) with various solutions has been advoccated to enhance rapid ingrowth of tissue and stabilization of the implant. A comparison of Proplast blocks infused with saline solution, autogenous plasma, plasma with antibiotics, and control blocks was done after subperiosteal implantation in the maxillas and mandibles of primates. At specified time intervals from two to 66 weeks, implants were removed and examined for the character and degree of infiltration of tissue as well as for local cellular response to the alloplast. Microscopic examination of the implant showed increasing stabilization of tissue and decreasing local cellular response with increasing time of implantation. Examination of these parameters showed blocks infused with plasma to be least desirable.
Patients who have a maxilla that is retruded or hypoplastic, or both, but who have a mandible of normal position and size, will have degrees of flatness in the middle third of the face. Using systematic clinical evaluation and cephalometric skeletal analysis, a clinically recognizable facial deformity manifested by retrusion or hypoplasia, or both, of the maxilla, anterior zygoma, and infraorbital rims has been recognized. This deformity has been classified as infraorbital maxillary deficiency. The purpose of this paper is to describe an infraorbital-maxillary osteotomy for correction of this dentofacial deformity and to give a rationale for its use. The design of this osteotomy is determined by the skeletal deformity and can be classified as either low or high. The objective is to produce simultaneously a functional occlusion and facial harmony. Two of eight cases corrected by this surgical treatment are described.
An overview of infection as it applies to the oral and maxillofacial region has been provided. The following conclusions are drawn: odontogenic infections are caused by microbes found in the host's oral flora; cultures of purulent material generally will yield three to six anaerobes and one aerobe, (the aerobe is usually a Streptococcus species); Gram stains of purulent material can aid in therapeutic strategies; anaerobic as well as aerobic cultures are necessary to isolate all pathogens; pathogens found in infections of bite wounds reflect the oral flora of the aggressor; early postoperative wound infections are caused by the host's own flora, whereas later infections may be caused by hospital-acquired bacteria; and hepatitis B and herpes simplex virus are occupational hazards. Recommendations have been made for antimicrobial prophylaxis and for treatment. We recognize that some of these selections may be controversial. For instance, the value of prophylactic antibiotics in orthognathic surgery is not well defined; recommendations were made only in certain instances. However, in severe penetrating maxillofacial injuries with devitalized tissue, recommendations for antibiotics were for broad and prolonged coverage. In this instance, use of antibiotics is considered therapeutic and not prophylactic. In each instance, we tried to validate the selection. Our rationale has been to choose the antibiotics most active against the likely pathogens; additionally, consideration was given to drug toxicity and adverse reactions. We regard penicillin as the preferred agent for prophylaxis and treatment of most odontogenic infections. Alternative drugs include cephalosporins, doxycycline, and clindamycin. Erythoromycin and tetracycline are considered less effective than the former agents. Finally, we believe that successful treatment of infection depends as much on changing the microenvironment of the infected tissue by debridement and drainage as on appropriate antimicrobial therapy.
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Hypermobility of the temporomandibular joint is often caused by trauma, by opening the mouth too wide, by having a mouth forced open during general anesthesia procedures, or by dental procedures. The capsule may be stretched to an extent that dislocation occurs more easily thereafter. An implant of Vitallium mesh attached to the zygoma to restrict anterior movement of the condyle is used to prevent recurrent dislocation of the temporomandibular joint.
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