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Biomedical subjects

O R Beirne

Publications and source records attributed to O R Beirne.

At least 19 recordsLinked to original sources
PubMed1991

Histologic evaluation of hydroxylapatite-coated versus uncoated titanium blade implants in delayed and immediately loaded applications.

It has been suggested that the long-term success of blade implants could be improved by placing the implants using a two-stage surgical protocol to allow the implant to develop a direct bony interface instead of a fibrous tissue interface. This study compared the implant interfaces of delayed and immediately loaded blade implants in nonhuman primates. A second objective was to compare the effects of hydroxylapatite coating on delayed and immediate loading applications. The delayed loaded uncoated titanium and hydroxylapatite-coated blade implants did osseointegrate. This study also suggests that hydroxylapatite-coated blade implants may form a direct bony interface even when they are loaded immediately after implantation, provided that they are splinted to a firm natural tooth.

Animals↗
PubMed1988

Osseointegration of two types of implants in nonhuman primates.

Branemark developed a dental implant that can reliably replace missing teeth. The success of this implant is attributed to a direct connection of bone with the implant (osseointegration). Several implants, including the Core-Vent implant, adhere to the requirements described by Branemark and his coworkers to achieve osseointegration, yet no studies have attempted to directly compare osseointegration of the Biotes implant with other implants. This study directly compared the response of bone to the unloaded and occlusally loaded Core-Vent and Biotes implants at the light microscopic level by using the nonhuman primate model. Histologic examination revealed that both Core-Vent and Biotes implants achieved osseointegration and maintained the direct contact with bone after 5 months of occlusal loading.

Animals↗
PubMed1988

Effect of hydroxylapatite, tricalcium phosphate, and collagen on the healing of defects in the rat mandible.

The effects of hydroxylapatite and tricalcium phosphate alone or mixed with collagen on the repair of surgically created bony defects in the mandible of 30 rats were evaluated by gross examination and light microscopy. When specimens were examined 4 and 12 weeks after placement of the implants, bone was observed in direct contact with the implants at the periphery; however, in the central portion of the defects, the implants were surrounded by fibrous connective tissue containing macrophages and a few multinucleated giant cells. Neither the hydroxylapatite or the tricalcium phosphate induced bony healing in the defect, and the addition of collagen did not interfere with healing. Because collagen does not alter healing, it might be possible to use it as biocompatible resorbable binder to confine particulate ceramic implants and inhibit their migration.

Animals↗
PubMed1987

Autogenous bone grafts for atrophic edentulous mandibles: a final report.

While autogenous bone augmentations for atrophic edentulous mandibles are not the ideal solution for this problem, we do not share the pessimism of other investigators. The average loss of bone over the 92-month observation period was 60% for this small sample of eight patients. However, there was an 81% gain in bone height in the premolar-molar regions when compared with presurgical measurements. Seven of the eight patients believed these procedures were beneficial.

Alveolar Ridge Augmentation↗
PubMed1986

Mandibular augmentation with hydroxyapatite.

This study investigated the success of hydroxyapatite mandibular augmentation in nine patients, the histologic response around hydroxyapatite, and the effect of collagen in localizing hydroxyapatite. It can be concluded that hydroxyapatite is biocompatible, causes minimal inflammatory response, and can increase denture retention. However, a large number of patients develop lip paresthesia, and hydroxyapatite migrates. Paresthesia might be avoided by altering the surgical technique to avoid manipulation of the mental nerve, and collagen might be a useful binder to confine hydroxyapatite particles. Further studies are in progress to develop new methods to place the hydroxyapatite and materials to confine it.

Adult↗
PubMed1986

Evaluation of patients for preprosthetic surgery.

The success of preprosthetic surgery and subsequent complete dentures depends not ony on the technical success of the procedures but also on the patient's satisfaction with the outcome. Studies of patients' satisfaction with their complete dentures confirm the experience of prosthodontists--that the problems described by patients do not always correlate with detectable anatomic deficiencies or technical faults in the prostheses. Since the responsibility for patient care is shared by both the surgeon and the prosthodontist, it is important that both specialists by involved in the screening process and evaluation of patients for preprosthetic surgery, prior to treatment. This article describes the basic criteria for patient evaluation, including signs that might indicate a poor prognosis for preprosthetic surgery. Everyone benefits if a realistic prognosis for the proposed combined treatment can be established before therapy is begun.

Consumer Behavior↗
PubMed1986

The effect of methylprednisolone on pain, trismus, and swelling after removal of third molars.

Thirty-one healthy patients whose third molars needed to be removed were randomly placed into two groups. Before sedation the control group (n = 16) received normal saline solution and the experimental group (n = 15) received 125 mg of methylprednisolone intravenously. Swelling was measured by photographic and face-bow techniques, trismus was determined by measuring maximal interincisal opening, and pain was evaluated by asking the patients to report the number of pain pills they used and assess th severity of their pain daily. The swelling and pain, but not the trismus, that developed after third molar removal were significantly reduced by a single dose of methylprednisolone.

Adolescent↗
PubMed1986

Viability of the retained bone core in the core-vent dental implant.

The survival of dental implants has been correlated with the formation of a bone-implant interface. This study was done to determine whether the recently developed Core-Vent dental implant forms a bone-implant interface without intervening fibrous tissue. Core-Vent implants were placed in four dogs, and healing was evaluated histologically 15, 30, 60, and 120 days after insertion. Bone grew through the implant vents to join with the inner bone plug, and the implants approximated the bone without an intervening fibrous tissue layer.

Alveolar Process↗
PubMed1986

Comparison of complications after bone removal from lateral and medial plates of the anterior ilium for mandibular augmentation.

6 patients whose mandibles were to be augmented with autogenous bone were divided into 2 groups of 3 patients each. In one group, autogenous donor bone was harvested from the medial plate of the anterior ilium, whereas in the second group bone was harvested from the lateral plate. Although some clinicians have asserted that there is less morbidity when bone is harvested from the medial plate, no difference between the 2 groups was noted in the length of hospitalization, amount of blood loss during surgery, incidence of seroma development, or need for a cane or walker. The decision to remove bone from the lateral or medial plates should be based on surgical access rather than incidence of complications.

Adult↗
PubMed1984

A method for assaying aryl hydrocarbon hydroxylase in man using fibroblasts cultured in vitro from oral mucosa.

Animal studies have linked aryl hydrocarbon hydroxylase (AHH) with cancer induction by polycyclic aromatic hydrocarbons (PAH), but the relationship between the activation of PAH by AHH and cancer induction in man is unclear. Studies using human lymphocytes to investigate this relationship have produced conflicting results. This report describes a technique for assaying AHH in fibroblasts isolated and cultured from normal human oral mucosa. Fibroblasts were cultured from normal portions of routine oral mucosal biopsy specimens obtained from 6 patients, and AHH activity was found in fibroblasts cultured from all the specimens. AHH activity was induced by 1,2-benzanthracene and reached a peak after 48 h. The assay had a pH optimum of 8.6 and an absolute requirement for reduced nicotinamide-adenine dinucleotide phosphate. The fibroblasts maintained their inducibility of AHH through 11 cell passages. Fibroblasts cultured from oral mucosal biopsy specimens offer several advantages over other systems for comparison of individual differences in AHH activity in man, including the consistent presence of inducible AHH activity, stability of enzyme activity in culture, provision of ample number of cells for study, and availability of oral mucosal specimens from patients having routine diagnostic biopsies.

Aryl Hydrocarbon Hydroxylases↗
PubMed1978

Agranulocytosis associated with an infected mandibular fracture.

This report describes a case of agranulocytosis associated with an infected mandibular fracture. Because agranulocytosis is most frequently associated with drug sensitivity, drug therapy is usually stopped or changed when the disease is discovered. This case demonstrates the need to evaluate the causes of agranulocytosis before stopping or changing a patient's medications.

Adult↗
PubMed1977

Regulation of 3-hydroxy-3-methylglutaryl coenzyme a reductase in minimal deviation hepatoma 7288C. Immunological measurements in hepatoma tissue culture cells.

The mechanism of action of serum lipoproteins and 25-hydroxycholesterol on 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase activity in hepatoma tissue culture (HTC) cells was investigated using antiserum against purified rat liver HMG-CoA reductase (Heller, R. A., and Shrewsbury, M. A. (1976)J. Biol. Chem. 251, 3815-3822). This antiserum cross-reacted with solubilized and membrane-bound HMG-CoA reductase from HTC cells. The enzymes from rat liver and HTC cells appeared antigenically identical. The increase in HMG-CoA reductase activity of HTC cells grown in medium which lacked serum lipoproteins was shown to be due to an increase in immunoprecipitable enzyme. In contrast, the 25-hydroxycholesterol suppression of reductase activity leads to a reduction in the antigenicity of the enzyme rather than a decrease in its number of molecules.

Alcohol Oxidoreductases↗