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Biomedical subjects

G R Barker

Publications and source records attributed to G R Barker.

At least 19 recordsLinked to original sources
PubMed1992

Prosthetic rehabilitation of the edentulous patient requiring a partial maxillectomy.

A variety of problems faces the prosthodontist attempting reconstruction of maxillary defects. This article reviews developments in materials and techniques of obturator prosthesis design for patients experiencing maxillectomy. The size of the maxillectomy defect is one of the main factors governing the prognosis for treatment. Many patients require special prosthodontic techniques. However, routine attention to extension of the prosthesis and balanced occlusion is essential. Obtaining satisfactory retention and stability in the definitive obturator prosthesis can be elusive. Resilient denture base materials are extremely useful in retaining the prosthesis, which obturates small defects. However, the flexibility of these materials makes them unsuitable in large maxillectomy cavities because of the deformation that occurs during mastication. Alternative forms of retention, eg., osseointegrated implants and sectional prostheses retained by magnets, are discussed.

Animals↗
PubMed1992

The facial nerve function coefficient: analysis of 100 normal subjects.

The Facial Nerve Function Index (FNFI) is a measure of asymmetrical facial movement and is a quick and easy method of monitoring the improvement of function in patients with facial nerve palsy. However, purely as a consequence of the way the index is formulated, and not primarily because of any tendency to biological asymmetry favoring one particular direction in the population, the FNFI has a highly skewed distribution. To remove the inherent asymmetry of the index, a modified index, the Facial Nerve Function Coefficient (FNFC), for which a symmetrical distribution is obtained, is proposed. A reference range for this index was derived.

Adolescent↗
PubMed1992

Experience with the Astra dental implant system.

The Astra Dental Implant System appears to be a relatively successful and economical method of osseointegration. This article lists its clinical components, explains how the system is fitted and discusses the preliminary results.

Aged↗
PubMed1991

Predominant cultivable flora in pericoronitis.

The predominant cultivable flora in pericoronitis was investigated by culturing pus from affected sites in 20 patients. Twenty colonies were picked at random from non-selective plates and identified using conventional biochemical and physiological tests, analysis of metabolic end-products by gas chromatography and protein profile analysis. The most frequently isolated organisms were Prevotella (Bacteroides) intermedia, Peptostreptococcus micros, Veillonella species, Fusobacterium nucleatum and Streptococcus mitis. Porphyromonas (Bacteroides) gingivalis was not isolated and asaccharolytic Eubacterium species were virtually absent. The predominant cultivable microflora in pericoronitis was found to be highly anaerobic in nature and superficially similar to that found in chronic periodontitis, although proposed marker organisms of severe periodontitis were absent.

Adolescent↗
PubMed1991

A computerized measurement of dental relapse following orthognathic surgery.

A computer-programmed osteotomy package was used to measure agreed values from lateral cephalograms preoperatively, postoperatively, and during the follow-up period. The variable representing the postoperative cephalometric analysis predicted by the program was included for further comparisons. The results were used to measure the degree of dental and skeletal relapse during the follow-up period, but only the dental relapse is discussed in the present study. There was a statistically significant proclination of the maxillary anterior teeth postoperatively that continued during the mean follow-up period of 16 months.

Adolescent↗
PubMed1990

A laboratory assessment of the antimicrobial effectiveness of glove washing and re-use in dental practice.

This study has assessed the ability of five hand-washing agents, Hibisol, Hibiscrub, Betadine, 70% isopropyl alcohol and bar soap, to decontaminate the surfaces of Biogel D, Surgikos Microtouch and Ansell Gammex latex medical gloves after repeated inoculation with Staphylococcus aureus. The glove and hand-washing agents were compared in a Latin Square experiment, and a standardized handwashing regime followed. Each of the gloves used in the study was later tested electrically for micropuncture formation. On the basis of microbial recovery, no specific combination of glove and hand washing agent proved superior, the marker organism being isolated on a sporadic basis. In addition, 17% of the gloves showed evidence of micropunctures after five sequential inoculations and washings. These results suggest that, even under strictly controlled conditions, glove surfaces cannot be reliably and consistently cleaned of microbial contamination, nor can they be guaranteed to remain puncture-free. Ideally, therefore, a new pair of gloves should be worn for each patient.

Cross Infection↗
PubMed1989

Cephradine penetration of mandibular bone.

The concentration of cephradine in serum and mandibular bone was assayed in 22 patients undergoing third molar surgery following a single 1-g intramuscular injection. Serum and cortical bone samples taken simultaneously contained mean cephradine concentrations of 12.41 micrograms/mL and 1.25 micrograms/g, respectively. These results, when compared with those reported for other bony sites, including femoral head and knee, show a reduced bone penetration with a bone-to-serum ratio of approximately 0.10:1.

Adult↗
PubMed1989

Spectral analysis of the masseter and anterior temporalis: an assessment of reliability for use in the clinical situation.

The electromyogram (EMG) of contracting muscles can be analysed in the frequency domain by spectral analysis. However, there is a need to establish the reproducibility of spectral parameters such as mean power frequency (MPF). This study examined the variation of MPF (masseter and anterior temporalis) between and within recording sessions. The MPF was found to be significantly reliable for both muscles, but considerable within-subject variation was found despite comprehensive measures to standardize recording methods and conditions. It is concluded that MPF may have clinical application in the diagnosis and treatment of patients with facial pain arising from muscle dysfunctions, but caution should be exercised in interpreting small changes in frequency, given the inherent variability of MPF.

Adult↗
PubMed1988

Maxillary chloroma: a myeloid leukaemic deposit.

A chloroma is described in the left quadrant of the maxilla in a 4-year-old girl. This patient had previously completed a course of chemotherapy for acute myeloid leukaemia, but had been off all drug therapy and in remission for 1 year prior to presentation. Chloroma is a well recognised, if uncommon, mode of presentation of acute myeloblastic leukaemia and a previous case of chloroma occurring in the mandibular gingival tissues has been reported (Reichart et al., 1984). An unusual feature in the present case is the appearance of the chloroma as a form of leukaemic relapse and as a solitary deposit which is itself uncommon in acute myeloblastic leukaemia. It is suggested that this chloroma was a leukaemic deposit which had spread from within the maxillary antrum or the tissues adjacent to the meninges.

Child, Preschool↗
PubMed1988

An intraoral combined blue naevus.

A combined blue naevus is described which lay below the epithelial surface of the attached lingual gingiva and the anterior region of the floor of the mouth. There was no visible pigmentation due to the masking effect of the overlying hyperkeratotic mucosa. Histologically the lesion was composed of a mixture of intramucosal naevus cells and dendritic melanocytes typical of a common blue naevus. Prophylactic excision of intraoral naevi is advised.

Humans↗
PubMed1988

Xeroradiography in relation to a Stafne bone cavity.

A symptomless radiolucency was noted to be lying between the inferior dental canal and the lower border of the left side of the mandible. Sialography of the left submandibular gland showed the existence of salivary gland tissue in relation to this radiolucency. However, xeroradiography revealed that this radiolucency was formed by an infolding of the lower border of the mandibular cortex, thus supporting the hypothesis that a Stafne bone cavity arises from the incorporation of salivary tissue into the developing mandibular cortical bone.

Bone Cysts↗
PubMed1988

A radiolucency of the ascending ramus of the mandible associated with invested parotid salivary gland material and analogous with a Stafne bone cavity.

A 60-year-old man presented with a well demarcated radiolucency in the posterior border of the left ascending ramus of the mandible, lying below the neck of the condyle. This area appeared to have the characteristic features of a bone cavity as previously described by Stafne. Although such cavities are now frequently recognized and generally accepted to represent entrapment of the submandibular, or more rarely sublingual, salivary gland tissues; Stafne (1942) only described their location as being, 'situated below the mandibular canal in the region as far forward from the angle as the third molar'. Developmental bone cavities have not been reported previously in the region of the ascending ramus of mandible, nor in relation to the parotid salivary gland. In the case described the radiolucency in the ramus appeared to be developmental in origin and was later shown by sialography, to be closely related to salivary gland tissues of the parotid gland.

Bone Cysts↗
PubMed1988

Effect of the calcium entry blocker verapamil on renal ischemia.

The ability of the calcium entry blocker verapamil to ameliorate the effects of renal ischemia was studied in ten sheep. Postanesthesia, bilateral cutaneous ureterostomies were placed in each sheep to facilitate urine collection and analysis. Both kidneys were made ischemic for one hour by occluding each renal artery. However, immediately before occlusion of the right renal artery, 0.05 mg/kg of verapamil was injected into the artery. Comparison of urinary creatinine excretion and urine volume for 72 h after reversal of ischemia demonstrated that those kidneys pretreated with verapamil had greater functional preservation (p less than .05). In this study, verapamil appeared to provide protection against renal damage after an ischemic insult.

Acute Kidney Injury↗