Biomedical subjects

N J Jepson

Publications and source records attributed to N J Jepson.

24 records · Page 2Linked to original sources

PubMed1995

A new temporary soft lining material.

The viscoelastic properties of a new light-activated temporary denture soft lining material have been monitored in vitro using a force/distance probe. Its baseline behaviour was characteristic of an elastic material and its compliance considerably less than that of both a short-term and a long-term soft lining material which were used as controls. Sample thickness had no appreciable effect on this compliance. These results suggest that the new product is likely to be perceived as being significantly harder by a patient. Twenty-four weeks' immersion in distilled water had no significant effect on either the compliance or elasticity of the test material and would suggest an improved durability when compared to other conventional short-term resilient denture lining materials, albeit at the expense of compliance.

Compliance↗

PubMed1994

Intake of non-starch polysaccharide (dietary fibre) in edentulous and dentate persons: an observational study.

Compromised masticatory efficiency places edentulous persons at risk of consuming a diet low in non-starch polysaccharide (NSP) ('dietary fibre'). No study has quantified NSP intake in edentulous people using a valid and reliable method of dietary assessment. The aim of this study was to provide quantitative data on NSP intake of edentulous persons, together with information on its dietary sources. Using the dietary history method, habitual intake of NSP was compared between edentulous persons (n = 30) and dentate persons (n = 30) between the ages of 40 and 60. Groups were matched for sex and social class. The edentulous group had a median NSP intake of 73 (31-211) g/week. This was significantly lower than that of the dentate group of 106 (25-225) g/week (P = 0.014). Neither group completely met current UK guidelines. NSP intake of 56% (n = 17) of the edentulous group was below 84 g/week, whilst 17% (n = 5) of the dentate group was below this figure--a level of intake below which increased occurrence of gastrointestinal complaints has been observed. The dentate group obtained significantly more NSP from all rich sources, including wholemeal breads, cereals, vegetables and fruit. Depending on their form and preparation, such foods are not necessarily difficult to chew. Specific advice on food selection is required to ensure the edentulous patient has an adequate intake of NSP. Education of the dentist for this purpose is of paramount importance.

Adult↗

PubMed1994

The clinical serviceability of two permanent denture soft linings.

Forty-four patients, most of whom had previous experience of soft linings, had a total of 62 soft linings placed in their lower complete dentures:32 of the silicone-based Molloplast-band 30 of the heat-cured plasticised acrylic Palasiv 62. Linings were evaluated at insertion and then at 3-monthly intervals. Surface changes and the reasons for lining replacement were used to assess the clinical serviceability of the linings. The median survival time of Molloplast-b linings was significantly greater than that of Palasiv 62, whose performance was inadequate with frequent failure due to surface deterioration, with and without a failure of bonding. Denture fracture was the most common cause of lining failure for Molloplast-b and occurred more frequently than with Palasiv 62. Fading and lining discolouration was commonly observed for both materials.

Acrylic Resins↗

PubMed1993

Evaluation of the viscoelastic properties of denture soft lining materials.

Denture soft lining materials are widely used in prosthetic dentistry. Their success has been attributed to their softness and resilience, properties described by their viscoelasticity. Though these properties have been extensively investigated in laboratory studies, clinical studies have been limited. The viscoelastic properties of the temporary soft lining material Coe Soft and the permanent soft lining materials Palasiv 62 and Molloplast-B have been studied using a force/distance probe whereby penetration was measured against time under constant stress. Derived values of an initial and time-dependent compliance has allowed a quantitative in vivo and in vitro assessment of freshly prepared samples of each test material and comparison between materials. The baseline behaviour of each test material in response to the test regimen was similar for both clinical and laboratory specimens. Three types of behaviour could be identified: (i) constant strain in which penetration was clearly less than specimen thickness--elastic behaviour (Molloplast-B); (ii) constant strain in which the penetration was equal or nearly equal to specimen thickness--apparent elastic behaviour (Coe Soft); (iii) strain which increased with time of load application--viscoelastic behaviour (Palasiv 62). The mean and range of baseline clinical thickness for Coe Soft was approximately half that seen for the permanent soft lining materials. There was a much smaller range in the baseline compliance of all materials than might have been anticipated from a knowledge of their relative softness.

Acrylic Resins↗

PubMed1993

Age changes in the viscoelasticity of permanent soft lining materials.

Age-related changes in the viscoelasticity of an acrylic-based (Palasiv 62) and silicone (Molloplast-B) permanent soft lining material were evaluated in parallel clinical and laboratory longitudinal studies using a force/distance probe. Changes in the viscoelastic properties of Palasiv 62 in clinical use were characterized by a significant and continued reduction in both initial and delayed compliance. That is, the material became harder whilst still retaining the underlying pattern of viscoelasticity seen at baseline. Laboratory immersion in distilled water resulted in significant reductions in compliance values. These reductions were cumulatively similar to those seen clinically but did not occur as rapidly. There was evidence of small, continued reductions in the measured thickness of clinical linings of Palasiv 62. The clinical and laboratory compliance of Molloplast-B remained stable over time. Ageing did not affect the essential elasticity of this material.

Acrylic Resins↗

PubMed1993

Age changes in the viscoelasticity of a temporary soft lining material.

The viscoelastic properties of a widely used temporary soft lining material have been monitored in vivo and in vitro using a force distance probe. Over a period of 8 weeks' clinical use, Coe Soft demonstrated a significant and continued reduction in compliance with time, the reduction being particularly rapid over the first week. These changes were not associated with a reduction in measured lining thickness for which significant changes were not found. In vitro immersion in water, saline or artificial saliva was characterized by a rapid and significant reduction in compliance values over the first week. Further continued reductions in compliance values were only observed in artificial saliva over 8 weeks, and on prolonged immersion in distilled water over 96 weeks. All reductions in compliance were significantly less than those seen clinically.

Acrylic Resins↗