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Biomedical subjects

R G Newcombe

Publications and source records attributed to R G Newcombe.

At least 163 records · Page 9Linked to original sources
PubMed1993

A 6-month home usage trial of a 1% chlorhexidine toothpaste (II). Effects on the oral microflora.

The effects of 1% chlorhexidine and 1% chlorhexidine/fluoride dentifrices on supragingival plaque flora were investigated in a 6-month home-usage study. 146 subjects were studied from whom plaque around 6 teeth was collected at baseline, 6 weeks and 24 weeks. Total anaerobic counts were reduced at 6 and 24 weeks in both active groups compared to control. No differences were seen in any other bacterial parameters. There was a significant decrease in the susceptibility to chlorhexidine of bacteria recovered from the subjects on the active treatments compared to control but, since the magnitude of effect was less than one dilution, this was not thought to be of any clinical significance.

Adolescent↗
PubMed1993

A study of Spanish sepiolite workers.

BACKGROUND: Sepiolite is an absorbent clay that is used as pet litter. It forms thin crystals, which are a transition between chain and layered silicates. Inhalation studies in animals have shown no evidence of pulmonary damage. This paper reports a cross sectional study of the total work force of the largest sepiolite production plant in the world. METHODS: Two hundred and eighteen workers (210 men and eight women) were studied. Height, age, and smoking history were recorded. Chest radiographs were read according to the International Labour Office (ILO) classification by two readers. Readings were used to construct a numerical score, which was then used in statistical analyses. Forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) were divided by the square of the height. Casella size selective personal samplers were used in randomly selected operatives to collect dust eight years before the rest of the study was carried out. These samples were evaluated gravimetrically. Total dust samples were examined by optical and electron microscopes. Results were analysed by bivariate linear regression, chi 2 tests, and analysis of variance. RESULTS: When allowance was made for smoking habit workers exposed to dry dust showed a significantly greater decline in FEV1 with age than workers with little exposure to dry dust. A similar pattern applied to FVC. Radiographic score showed deterioration with age but no clear differences from other variables. High concentrations of dust were found in the bagging department and also in the classifier shed. CONCLUSIONS: The major finding was that lung function deteriorated more rapidly in those who had had more exposure to dust, but there was no evidence of any accompanying radiographic change.

Adult↗
PubMed1993

An in vitro study into the effect of a bacterial artificial caries system on the enamel adjacent to composite and amalgam restorations.

A microbial artificial caries system was used to produce caries-like lesions adjacent to amalgam and composite restorations. Polarised microscopy allowed measurement of outer and wall lesions depths. Comparison was made of the depths found in relation to the restorative materials, margin finishing procedures (composite group), varnish application (amalgam group) and thermal stressing. It was found that differences were detectable between the different restorative materials and the type of margin finishing procedure used in the composite group. Varnish application and thermal stressing had little effect. Some comparison is made between this microbial technique, other artificial caries techniques, and other methods of assessing marginal leakage.

Adolescent↗
PubMed1993

The plaque removal effects of single rinsings and brushings.

Chemical plaque removal is one mechanism whereby an agent could improve oral hygiene and gingival health. As with toothpastes most agents, when delivered as rinses, would be considered adjunctive to mechanical tooth cleaning procedures. The aim of this study was to determine whether selected commercial rinses exhibited clinically significant plaque removal properties alone or when combined with toothbrushing with water or a toothpaste. A group of 12 volunteers took part in this single blind, randomized placebo-controlled, 12 cell cross-over study, employing 6 rinses. During each regimen subjects accumulated plaque from a zero baseline over 72 hours. Plaque removal was then measured by index and area after first a single rinse of product and second a subsequent brushing with water or toothpaste. Prebrushing rinsing removed less than 5% of the plaque with little difference between agents. No rinse was more adjunctive than water to postrinse brushings. Most statistically significant differences arose with the chlorhexidine rinse being apparently less effective. However, the possibility of a disclosing dye interaction cannot be discounted as explaining this anomalous result. This study could not support any claim of a direct prebrushing rinse benefit greater than that provided by water to mechanical plaque removal by any of the products tested.

Adult↗
PubMed1992

Association between postpartum thyroid dysfunction and thyroid antibodies and depression.

OBJECTIVE: To define the relation between mood and autoimmune thyroid dysfunction during the eight months after delivery. DESIGN: Double blind comparison of the psychiatric status of women positive and negative for thyroid antibodies. Clinical examination and blood sampling for free triiodothyronine and thyroxine, thyroid stimulating hormone, and thyroid antibody concentrations at four weekly intervals. Psychiatric assessment at six, eight, 12, 20, and 28 weeks post partum. SETTING: Outpatient department of district hospital. PATIENTS: 145 antibody positive women and 229 antibody negative women delivering between August 1987 and December 1989. MAIN OUTCOME MEASURES: Thyroid status. Number of cases of mental ill health by the general health questionnaire, research diagnostic criteria, Hamilton 17 item depression scale, hospital anxiety and depression scale, and Edinburgh postnatal depression scale. RESULTS: Six weeks after delivery the general health questionnaire showed 62 (43%) antibody positive women and 65 (28%) antibody negative women had mental ill health (chi 2 = 8.18, p less than 0.005). Follow up of 110 antibody positive and 132 antibody negative women showed significantly greater depression by research diagnostic criteria in antibody positive women (47%) than antibody negative women (32%) regardless of thyroid dysfunction. Antibody positive women showed higher mean scores for depression on the Hamilton (6.01 v 3.89, p = 0.0002), Edinburgh (7.45 v 5.92, p = 0.031), and hospital depression scales (4.95 v 3.79, p = 0.003). CONCLUSION: Depressive symptoms are associated with positive thyroid antibody status in the postpartum period.

Autoantibodies↗
PubMed1992

Measurements of uterine volume: a comparison between measurements by ultrasonography and by water displacement.

The uterine volume was measured in 30 patients 24 hours before hysterectomy by ultrasonography using the prolate ellipsoid formula. At hysterectomy the volumes of the same uteri were measured again by water displacement. A comparison is made between the two methods of measurements. Although the correlation between the methods is high (r = 0.964) and the mean percentage bias very small (+2.0%), the agreement between the methods for 95% of subjects is between -33.6, 8% and +37.6%. This is a potentially large disagreement relative to the typical size of the uterus, indicating that ultrasonic uterine volume measurement by the prolate ellipsoid method is not adequately precise for clinical management of the individual patient.

Female↗
PubMed1992

Smoking habits in psoriasis: a case control study.

We have examined smoking habits in 108 patients with psoriasis, including some with palmoplantar distribution, and compared the results with matched controls from the community. There was a significant association between psoriasis, current smoking status (OR = 2.7, 95% CI 1.44-5.42, P less than 0.01) and smoking habits prior to the onset of disease (OR = 3.75, 95% CI 1.68-9.47, P less than 0.001). There was also a marked dose-response relationship; the relative risk of psoriasis in those currently smoking more than 20 cigarettes/day was significantly elevated (OR = 5.3, 95% CI 2.1-13.0, P less than 0.001). Separate analysis of patients without palmoplantar distribution of psoriasis showed a significant association with smoking prior to onset of psoriasis (OR = 3.6, 95% CI 1.5-9.8, P less than 0.001). Smoking may play a role in the aetiology of this common skin disorder.

Adolescent↗
PubMed1992

Comparison of six files to prepare simulated root canals. 1.

A total of 300 simulated root canals of various angles and positions of curvature in clear resin blocks were prepared by hand using either K-files, K-Flex files, Flexofiles, Flex-R files, Hedstrom files or Unifiles. Each file type was used to prepare 50 canals employing a linear filing motion and an anticurvature stepback technique. Part 1 of this two-part report describes the efficacy of the files in terms of preparation time, instrument failure, loss of canal length and weight loss from the blocks. Two-way analysis of variance confirmed that there was significant variation for each parameter between instruments, between canal types, and with interaction between instruments and canal types. Overall, preparation with Hedstrom files was significantly quicker than with any other file, whilst preparation with K-files and K-Flex files took significantly longer. Fracture and deformation of instruments occurred substantially less often with Flex-R and Hedstrom files, but significantly more often with Unifiles. Loss of working distance occurred with all file types, but was significantly greater in canals prepared with K-files. Unifiles and Hedstrom files were responsible for significantly more weight loss than the other files, whilst K-files produced significantly less weight loss. Canals with rough undulating walls were created most often by Hedstrom files and Unifiles. Overall, under the conditions of this study, Flexofiles, Flex-R files and Hedstrom files appeared to be substantially more effective than K-files, K-Flex files and Unifiles.

Analysis of Variance↗
PubMed1992

Comparison of six files to prepare simulated root canals. 2.

A total of 300 simulated root canals of various angles and positions of curvature in clear resin blocks were prepared by hand using either K-files, K-Flex files, Flexofiles, Flex-R files, Hedstrom files or Unifiles. Each file type was used to prepare 50 canals employing a linear filing motion and an anticurvature stepback technique. Part 2 of this two-part report describes the efficacy of the files in terms of the prevalence of canal aberrations, the amount and direction of canal transportation and the overall postoperative canal shape. Hourglass shaped canals were found in 4.5% of curved canals, the majority of these being created by K-files and K-Flex files. Perforations were seen in 6.3% of curved canals, the majority being produced by Flex-R files and K-files. Excessive removal of material from along the inner aspect of the canal curve occurred in 10.4% of canals, by far the majority being created by Hedstrom files. Transportation of canals was a consistent finding with all instruments. Two-way analysis of variance revealed how significant differences in the absolute magnitude of transportation occurred between instruments, between canal types and by an interaction between instrument and canal type. In general, transportation was towards the outer aspect of the canal curve at the end-point of preparation and the zip and elbow, but towards the inner aspect at the beginning of the curve. Further towards the orifice, transportation reverted to the outer aspect of the canal curve.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMed1992

Crossover trials comparing several treatments.

Designs exist for crossover studies in which the possibility of distortion by carryover effects is minimised. A novel design including 5 treatments and 15 subjects with this property is presented, along with existing designs. These designs incorporating balance for carryover effects should be used in preference to cyclical permutation designs. Statistical analysis of the resulting data is readily performed.

Analysis of Variance↗
PubMed1992

Oral carriage of yeasts, coliforms and staphylococci in patients with advanced malignant disease.

Many patients with advanced cancer have oral problems, some of which may have a microbiologic basis. The oral flora in such patients has not, however, been characterized. This study has assessed the prevalence of yeasts, coliforms and coagulase positive staphylococci in the oral flora of 197 patients with advanced cancer. Both imprint cultures (n = 197) and oral rinses (n = 161) were collected. Yeasts were isolated from the mouths of 83% of the patients, coliforms from 49.1% and coagulase-positive staphylococci from 28%. All these percentages are considerably in excess of reported levels for healthy individuals. The results indicate a loss of colonization resistance of the oral mucosa in terminal cancer, with potential implications for the development of mouth care regimes for such patients.

Adult↗
PubMed1992

Incidence of ulcerative colitis in Cardiff over 20 years: 1968-87.

The annual incidence of ulcerative colitis in the city of Cardiff was examined over a 20 year period. In the decade 1968-77, the mean annual incidence was 6.4 per 10(5) of the population compared with 6.3 for the period 1978-87. There was no difference in the distribution or extent of the disease between decades or between sexes. This contrasts with the increased incidence of Crohn's disease during the same period. The study included a survey of family practitioners which identified a further 19 patients (11% of the total).

Adolescent↗
PubMed1992

Age at onset and life table risks in genetic counselling for Huntington's disease.

Age related genetic risk data for carrying the gene for Huntington's disease in relatives at risk, based on a previously documented life table approach, are presented in a form allowing ready access for use in genetic counselling. Figures are given for first degree relatives and for second degree relatives showing varying age combinations of consultand and intervening parent at risk. Data are also given for the risk of developing Huntington's disease over varying finite periods in relation to age. The availability of this information in tabular form should help those involved in genetic counselling for this disorder in providing accurate risk estimates to relatives; the data are also of importance for combination with genotype information in predictive testing.

Adult↗
PubMed1992

Old versus new ECT.

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Confidence Intervals↗
PubMed1992

The effect of a number of commercial mouthrinses compared with toothpaste on plaque regrowth.

Mouthwashes are frequently used as adjuncts to oral hygiene. However, for some products there is little supportive evidence that rinses provide greater benefits than plain water or additional benefits to the plaque inhibitory action provided by toothpaste. This study was a single blind, randomized, cross-over design in which 6 rinses were compared for inhibitory action against plaque regrowth. The formulations were a cetylpyridinium chloride rinse, a prebrushing detergent rinse, a peroxyborate rinse a toothpaste slurry rinse, a chlorhexidine rinse, and a saline rinse. From a zero baseline, plaque regrowth at day 5 was significantly reduced by chlorhexidine compared to peroxyborate; and, in turn, significantly reduced by peroxyborate compared to the other rinses. There were no significant differences between saline or a toothpaste slurry and the cetylpyridinium chloride or prebrushing rinse products. The findings would appear pertinent to the value of the respective rinses as adjuncts to oral hygiene.

Adult↗