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Biomedical subjects

M Addy

Publications and source records attributed to M Addy.

At least 217 records · Page 12Linked to original sources
PubMed1985

Evaluation of a method to study the uptake of prednisolone sodium phosphate from different oral mucosal sites.

A filter paper disk method for the delivery of drugs to oral mucosal sites was evaluated. The water-soluble steroid prednisolone sodium phosphate was chosen as the tracer drug. The in vitro recovery of the steroid from the filter paper disks after placement onto glass was greater than 95% and within the pipetting error for the method. Filter paper disks containing 1.25 mg doses of prednisolone sodium phosphate were placed on three different intraoral sites for 5 minutes and the drug retention was calculated in six volunteers. The mean percentage retention at the three sites was 65.4% for the sublingual mucosa, 24.1% for the buccal mucosa, and 9.9% for the palatal mucosa. The differences between the sites were all significant. The method may be useful for studying the retention of other drugs at various oral mucosal sites and for determining the factors that affect such retention.

Absorption↗
PubMed1985

The pattern of adsorption of cationic antiseptics to polymethylmethacrylate.

Few studies have reported the maximum potential of surfaces to adsorb the cationic antiseptics and few comparisons between antiseptics have been carried out. The purpose of this investigation was to measure the maximum uptake of alexidine, cetyl pyridinium chloride, chlorhexidine gluconate and chlorhexidine acetate to polymethylmethacrylate and by the construction of adsorption isotherms determine the pattern of molecular attachment to the recipient surface. The mean maximum adsorption findings for these antiseptics demonstrated significantly greater uptake of cetyl pyridinium chloride than the other antiseptics and significantly less uptake of alexidine compared with the other antiseptics. All four antiseptics showed a Langmuir type adsorption isotherm consistent with the formation of a monolayer of molecules on the recipient surface. For chlorhexidine preliminary studies demonstrated that the pattern of adsorption was not altered by saliva pre-treatment of surfaces. No evidence of molecular multilayering was observed even at higher concentrations of the antiseptics. However, the maximum uptake on to the surface was significantly increased when no post-treatment washings were carried out. It was concluded that this increased uptake would be unlikely to play an important role in antiplaque activity because of its relative instability. The pH dependency for the adsorption of these antiseptics was demonstrated such that as previously observed for chlorhexidine gluconate at low pH adsorption is almost completely, or completely, prevented.

Adsorption↗
PubMed1985

Candidal carriage and plaque distribution before, during and after removable orthodontic appliance therapy.

Candidal counts at 6 mucosal sites in 33 subjects were estimated by imprint culture before, during and after removable orthodontic appliance therapy. Additionally, dental plaque scores and salivary pH were measured at each stage. Whole mouth and site prevalence of candida rose significantly during therapy before falling to levels approximating initial values. A similar pattern was seen for candidal counts for the whole mouth and at individual mucosal sites, although post-treatment densities were usually lower than originally seen. The number of sites colonised by candida and salivary pH also increased significantly during treatment and fell significantly afterwards. Only the upper palatal plaque scores rose during therapy and most other dental sites showed a gradual decrease in value during the course of the study. This could be attributed to regular monitoring of the patient's oral hygiene procedures. This investigation demonstrated a direct relationship between the presence of an acrylic appliance, candida and low salivary pH levels. Furthermore, removable appliance therapy had a positive, though transient influence upon the prevalence and density of oral candidal carriage, suggesting that the appliance may initiate the carrier state.

Adolescent↗
PubMed1985

The development and clinical use of acrylic strips containing anti-microbial agents in the management of chronic periodontitis.

Several methods have been used to deliver antimicrobial drugs into periodontal pockets. This study was concerned with the development of acrylic in strip form for such an application. Initially the release of chlorhexidine acetate from cold cured acrylic strips into water, was measured spectrophotometrically over a 15 day period. The release of chlorhexidine was highest on day 1, was reduced considerably by day 2 and then fell progressively to day 15. With the exception of the release on day 1 there was little difference in daily release from drug admixtures between 40 to 80 per cent. Comparison of the release of chlorhexidine, metronidazole and tetracycline demonstrated a similar release pattern for metronidazole and chlorhexidine but the daily release of tetracycline was considerably less. A bioassay indicated that all drugs were released in active form. In a clinical study chlorhexidine, tetracycline and metronidazole rods were placed in periodontal pockets for 2-3 days and the effects monitored by dark field microscopy. All drugs produced a proportional increase in cocci and marked reductions in other organisms, notably the curved and motile rods and spirochaetes. The effects of metronidazole and tetracycline were greater than those of chlorhexidine. A second clinical study compared the effects of metronidazole and tetracycline strips placed for 2 weeks. Clinically, both treatment methods had immediate effects upon pocketing, bleeding on probing and crevicular flow, which for metronidazole were maintained to the 3-month follow-up period. For tetracycline, the bleeding and crevicular flow were significantly reduced and maintained to the 3-month period but the initial pocket reduction returned to baseline levels by 3 months.(ABSTRACT TRUNCATED AT 250 WORDS)

Acrylic Resins↗
PubMed1984

Slow release metronidazole and a simplified mechanical oral hygiene regimen in the control of chronic periodontitis.

The present study is one of a series aimed at devising practical methods of control of chronic periodontitis that do not depend upon stringent interdental cleaning by the patient. The regime consists of professional and home care components thought to be realistic for general practice. Patients with chronic periodontitis, but without any complicating factor, such as systemic disease, recent antimicrobial therapy or occlusal traumatism were selected. They received an initial thorough scaling, root planing and an instruction in Bass brushing, using a multituft brush and a sodium fluoride toothpaste, but without emphasis on inter-dental cleaning. They were then assigned to one of two groups, one of which received, in addition to the above mechanical oral hygiene regime, low (0.5%) and the other high (40%) dose metronidazole locally in periodontal pockets once a week for 4 weeks. The low dose was supplied in the form of solution inside fine dialysis tubing. The high dose was in the form of metronidazole powder incorporated in acrylic resin. Plaque index, sulcus bleeding index, probeable pocket depth and gingival shrinkage were monitored during this period and for a further 8 weeks. Both groups showed highly significant reductions in (supragingival) plaque and periodontal inflammation, maintained at least 8 weeks after the end of the 4-week chemotherapy period. Reductions in SBI were greatest for the 40% metronidazole group. It was concluded that local metronidazole, even in the form of 0.5% metronidazole in a small portion of dialysis tubing, has a positive rôle in the control of chronic periodontitis.

Chronic Disease↗
PubMed1984

Comparison of the immediate effects on the sub-gingival microflora of acrylic strips containing 40% chlorhexidine, metronidazole or tetracycline.

In the management of chronic periodontitis, there has been a renewed interest in the local delivery of antimicrobial drugs into periodontal pockets. This study assessed the effects of the acrylic strip delivery system containing chlorhexidine, metronidazole or tetracycline on subgingival microflora assessed by dark field microscopy. Strips containing 40% chlorhexidine, metronidazole or tetracycline were placed for 2 to 3 days into pockets greater than 6 mm which bled on probing. Plaque samples were obtained before and after treatment and counts of morphological and motile groups of organisms were made by dark field microscopy. Prior to treatment, the dark field microscopic counts were similar to those previously reported for diseased sites with motile bacteria, in particular spirochaetes, present in high numbers. Following treatment, all 3 antimicrobial drugs produced a significant increase in the proportion of cocci and significant decreases in all other types of organisms. Motile organisms, in particular, were markedly reduced and spirochaetes could not be recovered from some sites treated with metronidazole and tetracycline. Metronidazole was significantly more effective than tetracycline or chlorhexidine on spirochaetes. The results indicate that acrylic strips may be useful in the management of chronic periodontitis as an adjunct to routine mechanical methods.

Acrylic Resins↗
PubMed1984

Simple bacteriological methods to assess changes in subgingival microflora produced by metronidazole-containing acrylic strips placed into periodontal pockets.

Dark field microscopy is perhaps the simplest microbiological technique to monitor the effects of treatment methods on bacterial plaque. However, the method provides qualitative rather than true quantitative data. This study attempts to measure changes in flora by a number of methods following the placement of 40% metronidazole acrylic strips into periodontal pockets. 10 patients with periodontal pockets greater than 6 mm which bled on probing had acrylic strips placed for 2 to 3 days. Prior to insertion and after removal, subgingival plaque samples were collected into 1 ml of saline and processed as follows. (a) Dark field microscopy for qualitative shifts. (b) Gram stain for differential counts. (c) Counting chamber for total counts. (d) Serial dilution and culture for total cultivable counts. After treatment the significant changes were as follows. (a) % increase in cocci and decreases in other forms, particularly motile organisms. (b) Gram-positive cocci increased and Gram-negative bacilli decreased. (c) Total counts obtained by the sampling method decreased greater than 80%. (d) Total cultivable counts decreased greater than 75%. (e) The efficiency of culturing appeared low and the potential problems of sampling to quantification were identified. The consistency of the changes produced suggested that using simple bacteriological techniques it was possible to show marked changes in the numbers and types of organism present in subgingival plaque following the use of local antimicrobial therapy.

Acrylic Resins↗
PubMed1984

The effect of surface adsorption and staining reactions on the antimicrobial properties of some cationic antiseptic mouthwashes.

The phenomenon of surface adsorption appears fundamental to the antiplaque activity of the cationic antiseptics. Moreover, reaction with chromogenic material is relevant to the local side effect of staining. The purpose of this investigation was to determine how such local reactions affect the antibacterial activity of some of these antiseptics. The minimum inhibitory concentration (MIC) of commercial mouthrinses containing alexidine, cetyl pyridinium chloride, chlorhexidine gluconate and hexetidine against Oxford staphylococcus (NCTC 6571) and Escherichia coli (NCTC 10418) was established by tube dilution. The effect on the MIC values against O. staphylococcus of adding polymethylmethacrylate polymer or against E coli of adding a standard tea solution was then measured. The zones of inhibition around acrylic blocks soaked in the respective antiseptics, with and without postexposure washings, were measured. The effects on zone width of placing the antiseptic-soaked blocks in tea were recorded. The MIC values of alexidine, cetyl pyridinium chloride and chlorhexidine gluconate, but not hexetidine, were all increased by adding polymethylmethacrylate to cultures. Tea added to the culture increased the MIC values against E. coli for alexidine, chlorhexidine and hexetidine, but not for cetyl pyridinium chloride. Zones of inhibition around antiseptic-treated blocks were reduced by washing and, in the case of hexetidine, completely abolished. Tea-soaking further reduced the zones of inhibition for alexidine and chlorhexidine, but not cetyl pyridinium chloride.(ABSTRACT TRUNCATED AT 250 WORDS)

Adsorption↗
PubMed1983

Comparison of plaque accumulation after topical application and mouth rinsing with chlorhexidine gluconate.

This study measured plaque accumulation on anterior teeth after topical or mouth rinse application of 0.2% chlorhexidine gluconate. Compared with water plaque scores were highly significantly reduced. There was no significant difference in plaque scores between topical application or mouth rinsing. The importance of locally adsorbed chlorhexidine is emphasised and the relevance of an oral reservoir effect questioned.

Administration, Topical↗
PubMed1983

Dentine hypersensitivity--a review. Aetiology, symptoms and theories of pain production.

The exposure of cervical dentine has a multifactorial aetiology and pain may frequently be elicited by a number of stimuli. Management of the condition, dentine hypersensitivity, tends to be empirical because of the lack of knowledge concerning the mechanism of pain transmission through dentine. The pulpal changes associated with the condition and any modulating effect on symptoms are by no means clearly established. Evidence suggests that exposed dentine which is sensitive exhibits patent tubules. The question of how pain is initiated across the dentine has received considerable attention but still remains somewhat debatable. The literature reviewed indicates that, at most, nerve fibres only penetrate a limited distance along some dentinal tubules. The theories that either the odontoblasts and their processes act as dentinal receptors or the nerves in the pulp are the pain receptors, are discussed. Evidence for the stimulation of pulp nerve fibres by a hydrodynamic mechanism would appear the most likely mechanism. Nevertheless, whichever theory proves to be correct, occlusion of dentinal tubules would appear an essential prerequisite for an effective desensitising agent.

Dentin↗
PubMed1983

Dentine hypersensitivity--a review. Clinical and in vitro evaluation of treatment agents.

A large number of compounds have been employed in the management of dentine hypersensitivity. The symptomatic nature of the condition and its variability poses many problems to any evaluation of effect. Several semi-quantitative methods of response have been used; however, at this time it is uncertain what advantages they hold over the patients' subjective assessment of improvement. A review of the clinical studies reveals that a positive result for every agent tested to date may be found. Nevertheless considerable placebo responses have been obtained and equivocal results are occasionally reported. The fluorides and metal salts, particularly of strontium, have been most studied when used either in solution or delivered in toothpaste formulations. For these compounds the literature contains considerable information concerning the reaction with dental hard tissues which can be extrapolated into hypotheses for the modes of action in relieving dentine hypersensitivity. Moreover, some in vitro studies provide useful information concerning the effects of certain compounds on dentine, and are consistent with the clinical data. Unfortunately, contradictory findings and anomalies between clinical and in vitro effects still prevent the development of a sound clinical basis for the treatment of the condition. Moreover, there is a need to recognise those factors which predispose to dentine exposure, if the prevention of the occurrence or re-occurrence of hypersensitivity is to be achieved.

Calcium Hydroxide↗
PubMed1983

Subgingival metronidazole in acrylic resin vs. chlorhexidine irrigation in the control of chronic periodontitis.

After initial scaling, root planing and cleaning of subcontact areas, chronic periodontitis patients received oral hygiene instruction consisting of Bass toothbrushing using a sodium fluoride toothpaste, but without stress on interdental cleaning. They were then assigned to two groups, one of which self-administered 0.2% chlorhexidine solution subgingivally, once daily for 4 weeks, while the other was subjected to subgingival application of acrylic resin strips containing 40% metronidazole once weekly for 4 weeks. Plaque Index, Sulcus Bleeding Index, probeable pocket depth and gingival shrinkage were assessed for this treatment period and for a further 8 weeks. Highly significant improvements compared with baseline values were achieved and maintained to the end of the study. There were no significant differences between the groups at any time, except for Sulcus Bleeding Index which at Days 56 and 84 showed metronidazole to be superior. It was concluded that the regimens selected were equally effective in improving periodontal health over a 3-month period.

Acrylic Resins↗