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Biomedical subjects

A J Preston

Publications and source records attributed to A J Preston.

16 recordsLinked to original sources
PubMed2005

Determination of the pH of peri-implant crevicular fluid in successful and failing dental implant sites: a pilot study.

The aims of this pilot study were to assess if a standard technique which is used to determine the pH of dental plaque around natural teeth (the 'touch electrode' technique) could be modified for use to determine the pH of crevicular fluid around dental implants, and to evaluate any possible changes in the peri-implant crevicular fluid pH in successful and failing implants. pH measurements of a sample of subjects' (n=17) peri-implant crevicular fluid of both successful and failing dental implants present in the same oral cavities were performed using iridium/iridium oxide (Beetrode) electrodes with 100 microm sensing tips, connected to an Orion 720 A pH meter. The technique appeared to be satisfactory for the purpose intended. The mean pH of the successful implants was 6.80 [STD+/-0.4; 95% confidence intervals (CI), 6.50-7.0], and that for the failing dental implants was 7.20 (STD+/-0.6; 95% CI, 6.90-7.50). The results showed that the technique described could be satisfactorily used to determine the pH of peri-implant crevicular fluid at dental implant sites, and that there was a significant difference between the pH of successful and failing dental implants (P<0.05). However, the results obtained should be interpreted with caution in view of the small sample size used in this pilot study.

Adult↗
PubMed2004

Developments in dental plaque pH modelling.

OBJECTIVES: The objectives of this review were to give a comprehensive account of the methods used to determine dental plaque pH over the last 50 years, to review how these methods have been used in dental cariology research and to give an update as to how dental plaque pH studies might be developed in the future. DATA: Published, referred papers and abstracts of conference proceedings in the literature were reviewed. SOURCES: A comprehensive search of the electronic databases PubMed and Medline, was undertaken. In addition, a hand search of the Index Denticus was done to identify relevant citations before 1966. STUDY SELECTION: Relevant published literature in peer-reviewed publications was reviewed. No additional inclusion criteria were applied. CONCLUSIONS: This comprehensive review gives an account of the background to, history of, relative merits and demerits of, applications of and future of dental plaque pH technologies.

Animals↗
PubMed2003

A study investigating the formation of artificial sub-surface enamel caries-like lesions in deciduous and permanent teeth in the presence and absence of fluoride.

OBJECTIVES: Clinical and in situ studies have shown that caries formation and progression is faster in primary than in permanent teeth. Ambient levels of fluoride are also known to influence the processes of carious lesion formation. The aims were, firstly to investigate the incidence of artificial sub-surface caries lesion formation in the enamel of deciduous and permanent teeth in vitro. Secondly, to compare quantitatively the mineral content and distribution of these lesions and assess the possible influence of fluoride upon the lesion parameters. METHODS: Twenty primary molars and 20 permanent premolars were randomly assigned to one of four experimental groups. Samples in each experimental group were immersed in a 0.05M lactic acid gel (6% w/v hydroxyethyl cellulose, pH 4.5) either in the absence or presence of fluoride for 7 days. Subsequently, lesion parameters of mineral loss (vol x % microm) and lesion depth (microm) were assessed by transverse microradiography and image analysis. RESULTS: No significant differences existed between the lesion parameters of permanent and primary teeth (P=0.20). Irrespective of tooth type, lesion parameters were significantly reduced in samples demineralised in the presence of fluoride (P< or =0.002). CONCLUSIONS: Fluoride significantly reduces the severity of sub-surface caries lesions formed in vitro and in contrary to previous studies, there were no significant differences in lesions parameters between permanent and primary teeth.

Cariogenic Agents↗
PubMed2002

Implant complications and failures: the fixed prosthesis.

The implant-retained fixed prosthesis has been advocated as an effective restoration offering significant benefits over conventional prosthetics. The success of treatment depends on careful pre-surgical planning and prosthesis design. This paper outlines some common complications encountered during the planning, fabrication and maintenance of both large and small fixed prostheses and suggests how these complications can be minimized.

Bite Force↗
PubMed2001

The efficacy and safety of once-daily Kytril (granisetron hydrochloride) tablets in the prophylaxis of nausea and emesis following fractionated upper abdominal radiotherapy.

This multicenter, randomized, double-blind study compared the efficacy and safety of once-daily oral granisetron 2 mg (n = 134) and placebo (n = 126) as prophylaxis for nausea and emesis in patients receiving upper abdominal fractionated radiotherapy. Patients were scheduled to receive 10-30 fractions of radiotherapy; granisetron (two 1-mg tablets) or placebo was administered 1 hr before radiotherapy on each scheduled treatment day. Treatment comparisons were made at 24 hr and at 10 and 20 fractions. Patients treated with granisetron experienced greater emetic control than those treated with placebo as evidenced by median times to first emesis (35 vs. 9 days, p < 0.001) and first nausea (11 vs. 1 day, p < 0.001). Overall endpoint analysis showed that proportionally more granisetron than placebo patients were emesis free (57.5% vs. 42.1%, p = 0.0047) and nausea free (30.6% vs. 16.7%, p = 0.0042). Furthermore, 25% more granisetron-treated than placebo-treated patients were emesis free and 20% more were nausea free on at least 80% of study treatment days. The most commonly reported adverse experiences in granisetron-treated patients were diarrhea, asthenia, and constipation. These findings demonstrate that a once-daily, 2-mg dose of oral granisetron is well tolerated and significantly more effective than placebo in preventing nausea and emesis induced by fractionated radiotherapy to the upper abdomen.

Abdomen↗
PubMed2000

Endodontics in the adult patient: the role of antibiotics.

OBJECTIVES: The aim of this study was to review the published work on the indications and efficacy for antibiotics in endodontic therapy. DATA SOURCES: Published works in the medical and dental literature. STUDY SELECTION: Evaluation of published clinical trials in endodontic and other pertinent literature. CONCLUSIONS: Antibiotics are not routinely indicated in the practice of endodontics. Therapeutic antibiotics may be required as an adjunct to operative treatment when there is pyrexia and/or gross local swelling; they are only rarely indicated in the absence of operative intervention. Prophylactic antibiotics may be required for certain patients who are susceptible to serious infective sequaelae.

Adult↗
PubMed2000

Oral care of elderly patients: nurses' knowledge and views.

It is important that healthcare professionals caring for the elderly in hospitals have a core knowledge of the orodental care requirements of their patients. The aim of this study was to determine the knowledge and views of nurses working on acute and rehabilitation care of the elderly wards about orodental care. One hundred nurses and healthcare assistants took part in this questionnaire study of which 58 were qualified nurses and 70 had been employed on care of the elderly wards for two or more years. Although the majority of the respondents were registered with a dentist and attended regularly, 40 did have 'some anxiety' about visiting their dentist. Approximately half of the study population regularly gave advice to their patients about dental care but their knowledge of and reasons for providing oral care and advice was often incorrect. The group's understanding of the availability of dental treatment provided by the National Health Service was also often inaccurate. It was concluded that a better core knowledge of the orodental care of older patients is required by all healthcare professionals who care for this group. It is also important that individuals in whom anxiety is associated with their own dental experience do not neglect to give orodental health advice to their patients.

Aged↗
PubMed1999

Pseudomonas aeruginosa septicaemia from an oral source.

Oral colonisation with aerobic Gram-negative bacilli (AGNB) is abnormal and usually indicates a medically compromised state in the host. It has been postulated that oral colonisation with AGNB may predispose a patient to serious systemic infection, but proof of this assertion is lacking. This report describes an elderly patient who had oral colonisation of Pseudomonas aeruginosa and developed septicaemia from an identical strain of this bacterium.

Aged↗
PubMed1999

Fluoride release from aesthetic dental materials.

The objective of the study was to compare the amounts of fluoride released by two glass-ionomer cements, a resin-modified glass-ionomer cement, a compomer and a fluoride-containing composite into deionized water and artificial saliva. Disc samples of each of the materials were fabricated and placed in either water or artificial saliva. Fluoride analysis of the media was performed periodically over 64 days. The data were analysed to show the rate of fluoride release per cm2 per hour for each material. The results showed that the fluoride release rate for all the materials in both solutions decreased dramatically after 24 h. The release rate in artificial saliva was significantly less than in water (P < 0.001). The resin-modified glass-ionomer cement consistently displayed the highest fluoride release rate per hour into both media.

Acrylic Resins↗
PubMed1999

Fluoride recharge of aesthetic dental materials.

The objective of the study was to compare the potential for fluoride recharge of two glass-ionomer cements, a resin-modified glass-ionomer cement, a compomer and a fluoride-containing composite in artificial saliva. Disc samples of each of the materials were placed into artificial saliva. The fluoride content of the artificial saliva was determined at various intervals up to 57 days. The discs were subjected to a 2 min exposure of NaF (500 parts/106). This recharge procedure was repeated at 64 and 120 days. The fluoride release was measured before and after recharge. The fluoride release for all of the materials increased after each exposure to NaF; however, the amount for the composite was very low. The resin-modified glass-ionomer cement displayed the greatest potential for fluoride recharge at 57 and 64 days (P<0.05). By 120 days, the amount of fluoride released in the 24 h post-recharge interval had decreased in all the materials. All the materials showed a potential for fluoride recharge. This effect, however, was minimal in the fluoride-containing composite.

Acrylic Resins↗
PubMedDate not supplied

Oral flora of elderly patients following acute medical admission.

The human oral microflora is diverse and is usually predominately composed of Gram-positive bacteria. It is uncommon to find Gram-negative bacilli (GNB) in healthy mouths. The incidence of infection with GNB rises in institutionalised, frail elderly subjects. There is also evidence of an association between intra-oral GNB presence and denture wearing. There have been few studies which have investigated intra-oral GNB carriage in acutely ill elderly patients. The aim of this study was to evaluate the oral flora of a group of elderly patients during an acute medical admission and to investigate any associations between the oral microflora and existing medical or oral factors. A total of 28 patients (17 females and 11 males; age: 74-93 years) on a care for the elderly ward were studied. Epidemiological data, detailed medical histories and oral examinations were undertaken. In addition, oral swabs of the palate area were taken to determine their oral flora. Twelve (43%) of the patients had GNB in their oral cavities. These patients were suffering from a variety of medical conditions and were on various drug regimes. There was a correlation between oral GNB presence and denture use. There was no association between GNB presence and denture hygiene. As oropharyngeal GNB colonisation can be associated with infections such as aspiration pneumonia, it is important in patients at risk that intra-oral organisms are identified and managed.

Aged↗
PubMedDate not supplied

A review of dentifrices.

Dentifrices have a role to play in the prevention of certain oral diseases, such as dental caries and gingivitis. The use of fluoridated dentifrices has had a dramatic effect on the caries rate in the western world over the last 30 years, and antibacterial, desensitizing and anticalculus dentifrice formulations have recently been developed. This paper provides a brief overview of the dentifrices currently available.

Cariostatic Agents↗