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Biomedical subjects

N H Wilson

Publications and source records attributed to N H Wilson.

At least 127 records · Page 7Linked to original sources
PubMed1994

Trends in glove use by dentists in England and Wales: 1989-1992.

The routine wearing of gloves during the dental treatment of patients forms an integral part of the recommended guidelines of many authorities worldwide. Compliance has been variable but there is evidence to show that this is increasing, as are other cross-infection control measures. A survey of glove use by general dental practitioners in England and Wales was carried out in 1989. This paper reports a follow up study in 1991/2 which aimed to identify any differences that had occurred in the interim. The results indicated that there was increasing compliance with recommended cross-infection control measures, although only one fifth of respondents were found to change gloves between patients. Of those practitioners who did not change gloves between patients, half considered that blood contact was not a reason for changing gloves. Comparisons are made with compliance rates in other countries and recommendations made for further education within the dental profession on the subject of cross-infection control.

Attitude of Health Personnel↗
PubMed1994

Fracture resistance of teeth restored with indirect composite resins: the effect of alternative luting procedures.

Some variations in luting technique from those recommended by manufacturers may hold clinical advantages, but it is also necessary to evaluate other parameters of the performance of the restored unit. Among these is fracture resistance. Accordingly, indirect composite resin restorations were placed in standardized preparations under standardized conditions. Restorations were placed in three groups of 10 teeth, each group with a different luting procedure: luting with a composite resin restorative material, conventional luting but without enamel etching, and luting with a 4-META material. In another group the restorations were luted in accordance with the manufacturer's recommendations, while two groups of sound teeth acted as control. Following compressive loading on a universal testing machine, the force required to cause fracture was recorded. The results indicated that optimal fracture resistance of teeth restored with indirect composite resin restorations was obtained when the 4-META-based luting material was used.

Acrylic Resins↗
PubMed1994

A clinical evaluation of the marginal adaptation of porcelain laminate veneers.

This paper reports the findings of a short-term (12 month) study to assess the initial adequacy and subsequent changes in the marginal adaptation of a series of porcelain laminate veneers (PLVs) placed in a highly selected group of patients by a single operator under strictly controlled conditions. The findings together with those of retrospective scanning electron microscope assessments of replicas of the veneered teeth indicate that ideal marginal adaptation is difficult to achieve when placing PLVs and that imperfections in the marginal adaptation of recently placed PLVs could be future sites for staining and caries in clinical service. It is suggested that, in prescribing PLVs, clinicians should take account of the limitations of such restorations.

Adolescent↗
PubMed1993

An assessment of the incidence of punctures in gloves when worn for routine operative procedures.

The value of glove wearing as part of dental surgery cross-infection control regimen is negated if gloves are punctured during use. An assessment of the procedures most likely to give rise to glove puncture is therefore of importance. Accordingly, 892 gloves worn by two dentists in general practice were examined for punctures, after being used in one of seven common operative procedures. It was found that gloves used for the treatment procedures investigated had a significantly higher proportion of punctures than unused gloves of the same type. Gloves used for surgical extraction showed the highest proportion punctured (16%). There was no significant difference in puncture frequency between the gloves worn on left or right hands irrespective of procedure.

Crowns↗
PubMed1993

Latex allergies.

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Gloves, Surgical↗
PubMed1993

Implications of the presence of dithiocarbamate in latex gloves.

Dithiocarbamate is used as a preservative or vulcanizing accelerator in the manufacturing process of latex gloves. Twenty-five types of gloves were tested for the presence of this additive by three methods: using an iodide/azide reagent; elemental analysis; and investigating the inhibition of the setting reaction of a vinyl polysiloxane putty. The results of these tests confirm that dithiocarbamates are the chemical components which cause the inhibition of the setting of a vinyl polysiloxane putty. Given this finding, and concerns regarding the possible effects of dithiocarbamate on skin, the use of dithiocarbamate-free gloves is recommended.

Dental Impression Materials↗
PubMed1993

A worldwide survey of the teaching of glass ionomer (polyalkenoate) cements.

This paper reports the findings of a worldwide survey of the teaching of glass ionomer (polyalkenoate) cements (GICs). A total of 324 questionnaires was returned from the 650 dental schools included in the study (50 per cent response), with the response ranging from 100 per cent (Australasia) to 4 per cent (USSR). The findings indicate that most primary dental degree students in the majority of countries investigated are presently taught the use of GICs in a wide range of applications using techniques which largely conform with those recommended by the manufacturers of such materials.

Africa↗
PubMed1992

The influence of dietary essential fatty acids on uterine C20 and C22 fatty acid composition.

The effect of dietary fatty acids on uterine fatty acid composition was studied in rats fed control diet or semi-synthetic diet supplemented with 1.5 microliter/g/day evening primrose oil (EPO) or fish oil (FO). Diet-related changes in uterine lipid were detected within 21 days. Changes of 2- to 20-fold were detected in the uterine n-6 and n-3 essential fatty acids (EFA) and in certain saturated and monounsaturated fatty acids. The FO diet was associated with higher uterine C20 and C22 n-3, and the EPO diet, with higher uterine n-6 fatty acid. High uterine C18:2 n-6 was detected in neutral lipid (NL) of rats fed high concentrations of this fatty acid, but there was little evidence of selective incorporation or retention of C18:2 n-6 by uterine NL. The incorporation of EFA into uterine phospholipids (PL) was greater than NL EFA incorporation, and uterine PL n-3/n-6 ratios showed greater diet dependence. Tissue/diet fatty acid ratios in NL and PL also indicated preferential incorporation/synthesis of C16:1 n-9, and C16:0, and there was greater incorporation of C12:0 and C14:0 into uteri of rats fed EPO and FO. Replacement of 50-60% of arachidonate with n-3 EFA in uterine PL may inhibit n-6 EFA metabolism necessary for uterine function at parturition.

Animals↗
PubMed1992

Developmental changes in the fatty acids of rat uterus and the influence of dietary essential fatty acids.

The effect of age on uterine fatty acid composition was studied in rats fed diets of differing fatty acid composition. Uteri of newly weaned 23-day rats had a higher fatty acid content and a higher proportion of short-chain (less than or equal to C18) fatty acids. Higher incorporation of C less than or equal to 18 fatty acids into neutral lipid (NL) and phospholipid (PL) of young 42-day rats compared with adult 240-day rats was detected. Uterine NL incorporated predominantly C less than or equal to 18 fatty acids which may be an important metabolic energy store in developing uterine tissue. Incorporation of C less than or equal to 18 fatty acids by uterine PL and NL was relatively unselective. In contrast, there was selective retention of arachidonic acid (AA) and docosahexanoic acid (DHA) throughout uterine development. An effect of dietary EFA on uterine n-3 and n-6 EFA was detected in each age group. There was marked retention of uterine AA when dietary supplies of n-6 EFA were low, but the total AA, eicosapentaenoic acid (EPA) and DHA in uterine PL remained constant in the three diet groups, and a constant content of AA, EPA and DHA was maintained throughout uterine development, regardless of diet. The degree of n-3 substitution achieved in this study inhibited uterine release of PG and parturition in adult rats.

Aging↗
PubMed1992

Glove use by orthodontists: results of a survey in England and Wales.

Attitudes to glove wearing during treatment of patients were tested by distribution of a questionnaire to 2000 dentists known to be practising under the National Health Service regulations in England and Wales. Of the dentists who replied, 41 specialist orthodontists, representing approximately one-sixth of all orthodontists working in the general dental services in England and Wales, were identified. Results indicate that 39 per cent of these orthodontic respondents wore gloves routinely for all patients and procedures, while 49 per cent wore gloves for some patients or procedures, with 12 per cent never wearing gloves. Reasons given by the occasional glove wearers for not wearing gloves routinely included loss of tactile sensation, perceived small risk, lack of comfort, and restriction of movement. Six per cent of those who replied had experienced skin irritation considered to be associated with glove wearing, while latex gloves were preferred by 78 per cent of respondents who wore gloves.

Attitude of Health Personnel↗
PubMed1992

Characterization of receptors involved in the direct and indirect actions of prostaglandins E and I on the guinea-pig ileum.

1. A study of the effects of prostaglandin E2 (PGE2) and eleven synthetic analogues on the guinea-pig isolated ileum preparation has revealed three distinct contractile actions, each associated with a different prostaglandin E (EP-) receptor subtype. In addition, PGI2 (prostacyclin) and its stable analogues can activate prostaglandin I (IP-) receptors to elicit both contraction and relaxation of the ileum. 2. Two of the PGE actions involve direct stimulation of the smooth muscle, being unaffected by 1 microM morphine treatment. One action is blocked by AH 6809 at micromolar concentrations and ICI 80205 and 16,16-dimethyl PGE2 are particularly potent agonists. Activation of EP1-receptors appears to be involved. The second action is unaffected by AH 6809; sulprostone and MB 28767 are potent agonists. Comparison with agonist potency rankings on the guinea-pig vas deferens indicates that EP3-receptors may be involved. 3. The third PGE effect and the stimulant PGI effect are blocked by morphine, indicating enteric neurones and/or sensory nerve terminals as sites of action. EP2-receptors may be involved in the PGE action, in view of the marked effect of morphine on the contractile actions of misoprostol, 11-deoxy PGE2-1-alcohol, 11-deoxy PGE1 and butaprost, all of which show some selectivity for EP2-receptors. The PGI action is most easily studied with cicaprost (EC25 = 1.3 nM), since iloprost, carbacyclin and to a lesser extent PGI2 also have agonist activity at EP1-receptors. 4. The contractile action of 17-phenyl-omega-trinor PGE2 on the ileum is unaffected by morphine. Since this analogue shows only weak agonist activity on the rabbit jugular vein (EP2 preparation) and guinea-pig vas deferens (EP3), it may be a more useful standard agonist than PGE2 in EPl1-receptor studies.5. In the presence of morphine and AH 6809, cicaprost inhibits histamine-induced contractions (IC25 = 22 nM). PGI2 and iloprost show mixed inhibitory/potentiating actions, whereas carbacyclin only potentiates histamine contractions. This IP-receptor-mediated inhibition may account for the bell-shaped log concentration-response curve of cicaprost (no inhibitors present) and the very marked block of iloprostinduced contractions by AH 6809.6. We have found no evidence for either IP-receptors mediating direct contraction or EP-receptors mediating inhibition of the ileum longitudinal smooth muscle, as has been suggested in the literature.7. In view of the complexity of prostanoid action on the guinea-pig ileum we feel that the preparation must be used with caution to ascertain the EPl agonist or antagonist potencies of novel compounds.

Animals↗
PubMed1992

Restorative decision-making behavior with magnification.

Assessment of occlusal fissure systems and restorations of amalgam in 100 extracted teeth were carried out by four examiners. An initial assessment, made with the naked eye, was repeated with binocular magnification (x 3). The data indicated that restorative decision-making behavior was modified when magnification was used, with an increase in the number of restorations planned for replacement and an increase in the number of tooth surfaces planned for restoration. Statistical analysis indicated that one of the examiners was particularly sensitive to the use of magnification and modified his treatment planning behavior considerably. As part of the process of adapting to the use of magnification, clinicians should review their decision-making behavior.

Decision Making↗
PubMed1992

Matrices: their development and in clinical practice.

Recent developments in amalgam alloys composite resin materials have highlighted the importance of meticulous restoration placement by the dentist. This paper discusses the selection and use of the matrix which is significant in both the quality and longevity of the final restoration.

Dental Restoration, Permanent↗
PubMed1992

Adaptation and condensation of amalgam restorations in Class II preparations of conventional and conservative design.

The purpose of this study was to investigate in vitro the adaptation and condensation of the proximal section of amalgam restorations placed in Class II preparations of conventional and conservative designs. The amalgam restorations were placed with traditional hand instruments with and without the aid of an automatic amalgam condenser. The restorations and sections of the restored teeth were examined and scored for adaptation and porosity. The restorations in the preparations of conservative design, especially those placed without the aid of the automatic condenser, exhibited more adaptation defects, porosity, and voids than did the restorations in the preparations of conventional design. It is necessary to identify and describe instruments and techniques that will facilitate the placement of amalgam restorations in preparations with limited access.

Analysis of Variance↗