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Biomedical subjects

T W MacFarlane

Publications and source records attributed to T W MacFarlane.

At least 55 records · Page 3Linked to original sources
PubMed1990

Salivary levels of mutans streptococci, Lactobacillus, Candida, and Veillonella species in a group of Scottish adolescents.

Salivary levels of mutans streptococci, Lactobacillus, Candida, and Veillonella species were investigated on three occasions at annual intervals in a group of 372 Scottish adolescents. Counts of the micro-organisms studied were logarithmically distributed, with Candida spp. being isolated from approximately half the subjects. Counts of lactobacilli, mutans streptococci, and candida were significantly intercorrelated, while veillonella were associated consistently with mutans streptococci alone. Levels of each of the four micro-organisms were significantly correlated over the three examinations, with levels of the Candida spp. being the most stable over the period studied.

Adolescent↗
PubMed1990

The effect of sucrose application and implantation of mutans streptococci on the microbial composition of three-week experimental plaque--an in situ study.

This study describes the predominant cultivable microflora of three-week-old plaque samples obtained from human enamel sites, on the basis of microbial identification of over 9000 fresh isolates. Lower removable appliances, on which were mounted enamel sections and slabs, were worn by five young adult subjects under three experimental protocols. These were (1) 'normal' plaque conditions, (2) extra-oral sucrose applications nine times daily, and (3) inoculation of each subject's own mutans streptococci onto the enamel test sites and sucrose applications, as described above. With the exception of slightly higher proportions of Gram-negative bacilli associated with slab plaque following sucrose application, no significant differences in percentage or absolute counts of organisms were found between normal and sucrose plaques. The inoculation of mutans streptococci, combined with extra-oral sucrose applications, was associated with significantly higher percentages and absolute mean counts of both mutans streptococci and lactobacilli, and lower proportions of S. sanguis and S. oralis. Although the isolation frequency of mutans streptococci increased in all subjects and the overall mean proportion rose following inoculation, considerable inter-subject variation was seen in mean percentage counts of these organisms isolated from the three-week plaque samples.

Adult↗
PubMed1990

An intra-oral appliance study of the plaque microflora associated with early enamel demineralization.

An intra-oral appliance model was used to investigate the composition of the plaque microflora associated with early enamel demineralization. Enamel sections, with exposed windows, were mounted on lower removable appliances, and the devices were worn by volunteers for three-week periods under three experimental conditions. These were: (1) "normal" plaque conditions, (2) extra-oral sucrose applications nine times daily, and (3) inoculation of each volunteer's own mutans streptococci onto the test sites and sucrose applications as described for (2). After 21 days, the plaque overlying each window was removed, and the bacterial composition was determined. Changes in mineral content of the associated enamel were measured by microradiography and microdensitometry, and the total mineral loss (delta z) that had occurred at each site was calculated. The 144 sites studied were divided into four demineralization groups by delta z value, with an increase in mineral loss from group 1 to group 4. A progressive and significant increase in the isolation frequency of mutans streptococci occurred from delta z group 1 to group 4 sites. These organisms were isolated from the plaque of every location with enamel mineral loss of over 1000 delta z units, but were not detected in 27% of the group 3 sites. Lactobacilli comprised 2% to 3% of the total cultivable microflora in groups 1-3 sites, but were found in significantly higher proportions (18%) at those enamel sites experiencing the most extensive mineral loss (group 4). No significant relationship was found between demineralization and the levels of Actinomyces species or Veillonella.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Presentation and antimicrobial treatment of acute orofacial infections in general dental practice.

Information on the presentation of orofacial infections and the use of antimicrobial agents in general dental practice in the United Kingdom was obtained using a postal questionnaire. Six hundred dentists were randomly selected and a total of 340 replies were received, giving a response rate of 57%. The dental practitioners estimated that acute infection was present in only a minority (approximately 5%) of patients. A total of seven different antibiotics were prescribed, in a variety of regimens, for the treatment of bacterial infection. However, the majority of dentists (46-62%) preferred a 5-day course of penicillin (250 mg, qid) for bacterial conditions other than acute ulcerative gingivitis, for which most practitioners (89%) prescribed 3 days of metronidazole (200 mg, tid). Nystatin was the most frequently selected anticandidal agent and topical acyclovir the most popular therapy for Herpes simplex infection.

Anti-Bacterial Agents↗
PubMed1989

Antibiotic susceptibilities of bacteria isolated from acute dentoalveolar abscesses.

The antibiotic susceptibilities of 166 bacterial strains (43 facultative anaerobes and 123 strict anaerobes) cultured from 50 acute dentoalveolar abscesses was assessed. Firstly, the effectiveness of five antibiotics, penicillin, amoxycillin, erythromycin, clindamycin and metronidazole, which are available to treat acute dental infection, was studied using a Stokes' comparative disc diffusion method. Secondly, the minimum inhibitory concentrations and minimum bactericidal concentrations were determined for isolates of the predominant species, especially those strains deemed resistant by the Stokes' method. It was concluded that the vast majority of bacterial strains (96%) were sensitive or moderately sensitive to the antibiotics tested. However, resistance was recorded for each of the antibiotics tested on at least one occasion. The MIC of penicillin, presently the drug of choice for acute dental infection, was between 0.03 and 2 mg/l for the majority of strains (96%).

Acute Disease↗
PubMed1989

Systemic metronidazole in the treatment of periodontitis.

The present study evaluated the effect of systemic metronidazole on advanced periodontitis in 10 patients with inadequate oral hygiene. Clinical and microbiological observations were made at a total of 173 bleeding pockets of 5 mm depth or more. The clinical observations comprised plaque index scores, dichotomous measurements of gingival redness and suppuration, pocket depths and attachment levels. The microbiological variables investigated were the % spirochaetes, % black-pigmented Bacteroides species, % facultative streptococci and presence of absence of Bacteroides gingivalis. At baseline, after clinical measurements and microbiological samples had been taken, each patient received a thorough scaling and root planing. After 3 months, the clinical measurements and microbiological sampling were repeated and a 5-day course of metronidazole was administered while one side of the mouth was scaled and root planed. After a further 3 months, the final measurements and samples were taken. In comparing pre- and post-treatment data, the following significant differences were observed: for debridement alone, a reduction in mean % spirochaetes from 11.5% to 4.9% and an increase in mean % streptococci from 4.7% to 8.8%; for metronidazole alone, a 0.3 mm gain in mean attachment level, a 0.4 mm reduction in mean pocket depth and a reduction in the frequency of suppurating sites from 32% to 16%; for debridement plus metronidazole, a 0.2 mm gain in mean attachment level, a 0.5 mm reduction in mean pocket depth and a reduction in mean % spirochaetes from 5.6% to 2.5%. Thus systemic metronidazole, either alone or accompanied by debridement, produced a modest clinical improvement after debridement alone had failed.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1989

Oral carriage of Candida species and coliforms in patients with burning mouth syndrome.

The oral carriage of Candida species and coliforms in a healthy adult population and a group of patients with burning mouth syndrome (BMS) was investigated. The intra-oral prevalence of Candida species and coliforms was higher in the BMS group compared with the controls. The most frequent yeast isolated from the BMS group was Candida albicans while Enterobacter and Klebsiella species were the most prevalent coliforms. The possible reasons and the significance of the above findings are discussed.

Burning Mouth Syndrome↗
PubMed1989

An in vitro method to study the adherence of oral bacteria to HeLa cells.

Exfoliated buccal epithelial cells have been widely used in microbial adherence studies, but present a number of problems due to their variable nature and to contamination with indigenous bacteria. An adherence assay was developed using HeLa cell monolayers which were washed with buffer, or treated with saliva or serum to mimic buccal or crevicular epithelial cells, respectively. A total of eighteen strains of oral bacteria tested showed a low affinity for untreated HeLa cells, but most strains adhered in high numbers to saliva treated HeLa cells. A few strains, usually present in the gingival crevice, demonstrated a high affinity for serum treated HeLa cells. Thus, salivary and crevicular fluid components appear to be specifically implicated in the selective adherence and colonization of bacteria on oral surfaces.

Actinobacillus↗
PubMed1988

The effect of chlorhexidine and benzydamine mouthwashes on mucositis induced by therapeutic irradiation.

A variety of mouthwashes are frequently used in the management of irradiation-induced mucositis. Benzydamine has recently been introduced for alleviating this condition. Its efficacy as a mouthwash was compared with chlorhexidine in two groups of patients receiving radiotherapy for oral carcinoma. Mucositis and pain were recorded over a 6 week period and oral carriage of Candida species, coliforms and Staphylococcus aureus was assessed using an oral rinse technique. There was no significant difference in the mucositis scores, overall pain scores or the yeast and bacterial species isolated between the two treatment groups. However, 58% (7 out of 12) and 92% (12 out of 13) patients reported oral discomfort when rinsing the mouth with chlorhexidine and benzydamine, respectively. In both groups, the most common coliform isolated was Klebsiella pneumoniae and the carriage of yeasts was significantly greater than that of coliforms. These results indicate that, although the individual patient acceptance of chlorhexidine is better than benzydamine, there is little difference between the two mouthwashes both in controlling pain and mucositis or in the oral carriage of the micro-organisms studied.

Aged↗
PubMed1988

Assessment of the pathogenicity of bacterial species isolated from acute dentoalveolar abscesses.

The pathogenicity of 20 strains belonging to nine bacterial species isolated from acute dentoalveolar abscesses was assessed individually and in two species combinations by subcutaneous inoculation of mice. Infections were produced by all the bacteria although variations were seen both in the type of lesion produced and the subsequent recovery of viable bacteria. Anaerobic gram-negative bacilli were recovered more often (p less than 0.05) at high concentrations (10(6)-10(9) cfu/ml) and produced a localised abscess with peripheral necrosis more frequently (p less than 0.001) than either Streptococcus milleri or anaerobic gram-positive cocci. Lesions induced by a combination of bacteria comprising anaerobic gram-negative bacillus and any other species yielded both strains at high concentration more often (p less than 0.001) than a combination comprising anaerobic gram-positive cocci and S. milleri. It is concluded that anaerobic gram-negative bacilli are major pathogens in acute dentoalveolar abscesses.

Acute Disease↗
PubMed1988

Longitudinal study of untreated periodontitis (I). Clinical findings.

The principal aim of this study was to investigate the use of certain clinical and microbiological criteria to predict periodontal breakdown during a 1-year period. A further aim was to establish whether the act of collecting subgingival plaque samples periodically throughout the observation period would have any effect on the clinical or microbiological variables. Only the clinical data is presented in this paper. The study population comprised 11 volunteers (aged 32-51 years) with persistent advanced periodontitis and inadequate plaque control in spite of a previous intensive course of hygiene therapy. From the left jaw quadrants, 89 teeth were selected, yielding 148 bleeding pockets of 4 mm depth or more. From the right jaw quadrants, 74 teeth were selected, yielding 117 bleeding pockets of 4 mm depth or more. All subjects were examined on 7 occasions at 2-monthly intervals when plaque index scores, dichotomous measurements of gingival redness, pocket depths and attachment levels were recorded. Bacteriological sampling was carried out at each visit for each site only in the left jaw quadrants while the right jaw quadrants were sampled only at the first and last visits. During the study, no subgingival instrumentation was performed, except at 3 sites which exhibited loss of attachment of 3 mm. These teeth were withdrawn from the study for ethical reasons. At the completion of the study, the sequential changes in probing attachment level at each site were subjected to regression analysis to determine the direction and extent of attachment change which had taken place at each site.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Longitudinal study of untreated periodontitis (II). Microbiological findings.

11 volunteer subjects with advanced chronic periodontitis participated in a 1-year longitudinal clinical and microbiological study. Subgingival plaque was collected at each of 7 visits from 148 pre-selected sites in the left jaw quadrants (test sites) and on the first and last visits, only from 117 sites in the left jaw quadrants (control sites). All sites were examined clinically at each of the 7 visits, and the microbiological markers investigated were the % spirochaetes and % black pigmented Bacteroides species in subgingival plaque. At the completion of the study, the sequential changes in probing attachment level at each site were subjected to regression analysis to determine the direction and extent of attachment change. Possible correlations between attachment change and % spirochaetes or % black-pigmented bacteroides were investigated using both individual sites and individual subjects. No significant differences were observed in either of the microbial variables between test and control sites. Possible correlations between the microbiological markers and attachment changes were investigated at baseline, at the 12-month visit and using the microbial data accumulated over all 7 visits. Significant differences were observed only at the 12-month visit when the % spirochaetes of both test and control sites were significantly lower in subjects showing the greatest improvement in attachment level. Overall, these results indicate that quantification of either spirochaetes or black-pigmented Bacteroides species cannot be used reliably to identify or predict disease-active sites.

Adult↗