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Biomedical subjects

Richard M Palmer

Publications and source records attributed to Richard M Palmer.

9 recordsLinked to original sources
PubMed2006

Investigation of periodontal destruction patterns in smokers and non-smokers.

BACKGROUND: Previous work has suggested that tobacco smoking has a local as well as a systemic effect on the severity of periodontal disease. OBJECTIVE: To test the hypothesis that smokers have more disease in the upper anterior region. METHODS: A retrospective stratified random sample of 49 non-smokers and 39 heavy smokers (>or=20 cigarettes/day) was obtained from a total of 3678 referred patients with adult periodontitis. Probing depth data were collected from clinical records and radiographic measurements were carried out on existing dental panoramic tomographs to assess the inter-proximal bone levels. RESULTS: The proportion of sites with "bone loss" 4.5 mm or greater was higher in smokers, the greatest difference being observed in upper anterior sites (smokers: 73.3+/-25.5%, non-smokers: 48.3+/-31.2%, p<0.001). A difference was also observed when the number of palatal sites probing 4 mm or greater in the upper anterior region was expressed as a proportion of all such sites in the mouth (smokers: 12.3+/-6.8%, non-smokers: 9.8+/-8.8%; p=0.050). CONCLUSION: The overall pattern of tissue destruction was consistent with a systemic effect of smoking. The suggestion of a marginal local effect of the smoking habit in maxillary anterior palatal sites requires further investigation.

Alveolar Bone Loss↗
PubMed2006

Maintenance of osseointegrated implant prostheses.

UNLABELLED: Implant-retained prostheses need to be re-evaluated on a regular basis. This should include review of the effectiveness of oral hygiene procedures to maintain soft tissue health, evaluation of the integrity and function of the prosthetic superstructure and comparison of radiographic bone levels at appropriate intervals. CLINICAL RELEVANCE: All dental care professionals need to be aware of the maintenance care requirements of patients treated with dental implants. With the increase in numbers of patients treated there will be greater demands to provide this care in general practices.

Alveolar Bone Loss↗
PubMed2006

Immediate and early replacement implants and restorations.

UNLABELLED: There have been rapid developments in dental implant treatment protocols to reduce the time between implant placement and restoration. Implants may be placed immediately following tooth extraction or following a period of healing to allow resolution of residual infection or sufficient bone and soft tissue healing. Early restoration and loading of implants has to be carefully controlled to avoid increased failure and complications. Advantages and disadvantages of the various techniques are described. CLINICAL RELEVANCE: The clinician should adopt a treatment protocol that ensures a high success rate and a long-term functional and aesthetic implant restoration. Rapid treatment protocols can be considered when they do not compromise these goals, and the clinician is sufficiently experienced in their application.

Dental Implantation, Endosseous↗
PubMed2005

Mechanisms of action of environmental factors--tobacco smoking.

AIM: To review the potential biological mechanisms underlying the effects of tobacco smoking on periodontitis. MAIN FINDINGS: Smoking has major effects on the host response, but there are also a number of studies that show some microbiological differences between smokers and non-smokers. Smoking has a long-term chronic effect on many important aspects of the inflammatory and immune responses. Histological studies have shown alterations in the vasculature of the periodontal tissues in smokers. Smoking induces a significant systemic neutrophilia, but neutrophil transmigration across the periodontal microvasculature is impeded. The suppression of neutrophil cell spreading, chemokinesis, chemotaxis and phagocytosis have been described. Protease release from neutrophils may be an important mechanism in tissue destruction. Tobacco smoke has been found to affect both cell-mediated immunity and humoral immunity. Research on gingival crevicular fluid has demonstrated that there are lower levels of cytokines, enzymes and possibly polymorphonuclear cells in smokers. In vitro studies have shown detrimental effects of nicotine and some other tobacco compounds on fibroblast function, including fibroblast proliferation, adhesion to root surfaces and cytotoxicity. CONCLUSION: Tobacco smoking has widespread systemic effects, many of which may provide mechanisms for the increased susceptibility to periodontitis and the poorer response to treatment.

Cell Adhesion↗
PubMed2002

A prospective study of single stage surgery for implant supported overdentures.

OBJECTIVES: To investigate the clinical and psychological outcomes with ball attachment supported mandibular overdentures on Branemark implants placed in a single stage surgical approach. MATERIAL AND METHODS Sixteen edentulous patients aged 32-74, with atrophic (flat) mandibular residual alveolar ridges, and a history of having difficulty coping with technically adequate mandibular dentures made within the last 2 years were recruited. Mark II Branemark implants were placed using a single stage surgical technique with healing abutments placed at time of surgery. Mandibular complete dentures were modified by relieving the areas over the abutments and a resilient liner was placed. After a period of 3 months, healing abutments were replaced with ball abutments and new complete dentures were made and the patients followed for a period of 2 years. Patients completed the General Health Questionnaire (GHQ) and answered further questions relating to the functional and psychological impact of complete denture wearing before treatment and 3 months after the dentures were provided. Patients additionally completed the GHQ 2 years after overdenture insertion. RESULTS: Six patients suffered from loss of one of their two implants in the first 2 years after placement. Three of the implants had failed to osseointegrate, which was detected at initial loading 3 months after placement. General Health Questionnaire scores were statistically significantly reduced after treatment and the improvement was maintained over 2 years. Responses to the functional and psychological questions were similarly improved. CONCLUSION: Single stage surgery led to a higher rate of implant failure than expected. Patients showed significant psychological health benefits from the treatment provided.

Adaptation, Psychological↗
PubMed2002

Cytokine release by osteoblast-like cells cultured on implant discs of varying alloy compositions.

OBJECTIVE: The aims of this study were (i). to assess the morphological features of osteo-blast-like, osteosarcoma cells (cell line SaOS-2) cultured on implant surfaces of varying alloys and (ii). to evaluate the biological activity of these cells, following their adhesion onto these surfaces. MATERIALS AND METHODS: SaOS-2 cells (6 x 104) were grown on titanium discs (diameter 30 mm), each with a surface of differing composition and roughness (commercially pure titanium, titanium-aluminium-vanadium alloy, oxide-blasted titanium and Astra-Tech special treatment titanium; the alloys are directly comparable with those used to construct implants). The cells were grown for time periods of 1, 3, 5 and 7 days, the media were collected and the cells were fixed with 2.5% glutaraldehyde. The media were then assayed (using enzyme-linked immunosorbant assay) for the levels of interleukin (IL)-1, interleukin-6, interleukin-18 and osteoprotegerin (OPG) produced by the cells. The discs, with the cells fixed on them, were viewed under scanning electron microscopy (SEM, x 2.0 k) to evaluate cell morphology. RESULTS: Following attachment, the cells changed their morphology and released local factors known to activate osteoclasts. Commercially pure titanium stimulated the cells the most and titanium-aluminium-vanadium alloy the least. All implant materials stimulated production of IL-1, IL-6, IL-18 above that produced by cells grown on Petri dishes (polystyrene). The titanium-aluminium-vanadium alloy allowed cell attachment but levels of IL-1 in this medium were significantly lower (31.5 +/- 5.2 pg/ml on same day) than cultures with pure titanium (201.8 +/- 11.5 pg/ml at day 5). The same pattern was observed with the IL-6, IL-18, and OPG with polystyrene appearing to stimulate most production of OPG. Titanium-aluminium-vanadium produced the least biological response.

Alloys↗