Biomedical subjects

M Addy

Publications and source records attributed to M Addy.

At least 19 recordsLinked to original sources

PubMed1995

Dietary staining in vitro by mouthrinses as a comparative measure of antiseptic activity and predictor of staining in vivo.

Extrinsic staining of teeth is a side-effect of some antiseptic mouthrinses. However, few of the many rinse products available to the general public have been investigated for their propensity to cause staining. Dietary factors play an aetiological role in staining and have been used in vitro to study and compare the activity of rinses. The aim of this study was to assess rinse products for staining in vitro and, through the staining reaction, to compare the activity of products containing the same ingredients. Perspex blocks, with or without saliva pretreatment, were soaked in rinses for 2 min, washed and placed in a standard tea solution for 60 min and then the optical density (OD) read on a spectrophotometer. The cycle was repeated 10 times for saliva and 17 times for no saliva specimens or until the maximum OD was exceeded. A series of three separate experiments was performed by this method. The maximum OD was not exceeded by any product before seven passages and therefore data were compared at six passages. For most products OD increased with saliva pretreatment. Some cetylpyridinium chloride (CPC) rinses stained comparably to a chlorhexidine rinse. CPC rinses, most of which contained the same concentration of the antiseptic, varied considerably in their propensity to induce staining and one was little different to water controls. A 0.1% chlorhexidine rinse stained slightly more than a 0.2%. A phenolic/essential oil product produced some staining but zinc, triclosan and other essential oil rinses did not stain.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗

PubMed1995

An assessment of approximal bone height in the posterior segments of 15-16-year-old children using bitewing radiographs.

The alveolar bone height in a total of 713 15-16-year-old children consisting of 364 males and 349 females was assessed using posterior bitewing radiographs. The distance between the alveolar crest (AC) and amelo-cemental junction (ACJ) on all molar and premolar teeth was determined from magnified images of the radiographs. Analyses of variance models were fitted in order to assess the dependence of the overall ACJ to AC distance on the inter-subject variables of gender and social class and the intrasubject variables of site, missing adjacent tooth, condition of the approximal tooth surface, and for mesial surfaces, gingivitis and pocket depth. The overall geometric mean for bone height for the whole population was 0.542 mm. The ACJ to AC distance for the vast majority of sites was below 2 mm. Site had a highly significant effect on bone height (P < 0.001): ACJ to AC distances were greater in the maxilla compared to the mandible (P < 0.001), greater for distal sites compared to mesial (P < 0.001) and significantly affected by tooth type (P < 0.001). Sites with missing adjacent teeth also had significantly increased distances (P < 0.001). The condition of the approximal tooth surface and the presence of pocketing or gingivitis did not have a significant association with bone height. The geometric mean AC to ACJ distance, adjusted for subject, site and social class was 0.577 mm for males and 0.506 mm for females (P < 0.001), but the main effect of social class was not significant.

Adolescent↗

PubMed1995

Dentine hypersensitivity: uptake of toothpastes onto dentine and effects of brushing, washing and dietary acid--SEM in vitro study.

Toothpastes are commonly used in the treatment of dentine hypersensitivity. One mode of action could be to block patent dentinal tubules with toothpaste ingredients or by abrasion to form a smear layer. Studies in vitro have shown that toothpaste abrasives have variable affinity for the dentine surface but retention may be limited. This SEM study extended previous work and determined the uptake in vitro of toothpaste ingredients onto the dentine surface and their retention when challenged by washing with water or orange juice. All products were seen to leave variable residues on the surface of etched or unetched dentine specimens, furthermore brush application produced some smearing with closure of previously open tubules. Washing with water and more particularly orange juice removed most residues and orange juice etched the dentine to open previously closed tubules. One product with an artificial silica abrasive was relatively resistant to both water and orange juice washings and in a pilot experiment showed some penetration into tubules not seen with another desensitizing product. These findings suggest that some abrasives may be usefully employed in desensitizing products, but without consideration of erosive factors in the aetiology of dentine hypersensitivity recurrences of the condition will be common.

Acid Etching, Dental↗

PubMed1995

Subpopulations of T lymphocytes in the peripheral blood, dermal lesions and lymph nodes of post kala-azar dermal leishmaniasis patients.

Distribution of different subpopulations of T cells in the dermal lesions, lymph nodes and peripheral blood of post kala-azar dermal lesihmaniasis (PKADL) patients was studied by using appropriate phenotypic markers for CD2+, CD4+ and CD8+ cells. Histopathological studies of skin lesions showed marginal to massive infiltration of mononuclear cells depending upon the duration of illness and type of lesions. Thus, while the hypopigmented patches were represented by small focal collections of lymphocytes with scanty parasites in the dermis, these were replaced at the nodular stage with massive granulomas consisting of lymphocytes, plasma cells and histiocytes with numerous amastigotes. The involvement of CD4+ and CD8+ cell types in these lesions also showed a gradual change from the appearance of a few cells of both the phenotypes in early hypopigmented type to massive accumulation of cells, primarily of CD8+ phenotype, in the granuloma of nodular type. However, the observed preponderance of CD8+ cells at the lesion site of chronic PKADL patients is in contrast to their peripheral blood CD4+/CD8+ cell ratio (1.9:1) which remained within the normal limits. Similar studies of lymph nodes from PKADL patients with lymphadenopathy revealed infiltration of the cortical areas by T cells which were more of CD8+ than CD4+ phenotypes. All these results document the involvement of CD8+ cells in leishmanoid lesions. Thus, it is likely that these cells, in association with appropriate subpopulations of CD4+ cells, play a profound role in the evolution of dermal pathology in PKADL.

Adolescent↗

PubMed1995

Gingival crevicular fluid glycosaminoglycan levels in patients with chronic adult periodontitis.

This study investigated levels of hyaluronan and chondroitin-4-sulphate in the crevicular fluid of patients with chronic adult periodontitis at diseased and healthy sites before and after treatment. The relationship between clinical diagnostic parameters and levels of glycosaminoglycans in gingival crevicular fluid were also analysed. Within each patient, 4 sites either mesial or distal and on single rooted teeth were classified as diseased or healthy using a modified gingival index, pocket depth and attachment loss. Crevicular fluid was collected from each site using glass micropipettes and analyzed for glycosaminoglycan content by cellulose acetate electrophoresis. Significantly higher levels of chondroitin-4-sulphate were detected at diseased sites prior to treatment correlating with increased pocket depth or attachment levels. Following a period of treatment consisting of oral hygiene instruction and root planing, the patients were reassessed for their response to treatment by measuring the modified gingival index, pocket depth, attachment loss and levels of glycosaminoglycans. Analysis of glycosaminoglycan levels at diseased sites that demonstrated a poor response to treatment also demonstrated significantly higher levels of chondroitin-4-sulphate than those sites that responded well to treatment. Hyaluronan levels were less significantly associated with clinically succesful treatment. This study confirmed the use of the sulphated glycosaminoglycan chondroitin-4-sulphate as a potential diagnostic aid of periodontal tissue destruction; however, further longitudinal studies are required to assess their performance.

Adult↗

PubMed1995

A 6-month home-usage trial of 0.1% and 0.2% delmopinol mouthwashes (II). Effects on the plaque microflora.

The effects of 0.1% and 0.2% delmopinol mouthwashes on supragingival plaque flora were investigated in a 6-month home-use study. 141 subjects were studied from whom plaque was collected at baseline, 12, 24, and 36 weeks. Overall, there were no consistent effects on microscopic or total counts. However, there was a significant reduction in the proportion of dextran-producing streptococci in the active groups compared to the control group throughout treatment. There was no colonisation by Candida or Gram-negative aerobic bacilli in the active groups nor was there any decrease in susceptibility to delmopinol. Delmopinol appears to mediate its anti-plaque effect without causing a major shift in bacterial populations, although dextran-producing bacteria appear to be affected, which may have relevance to this agent's mode of action.

Adolescent↗

PubMed1995

The use of plaque area and plaque index to measure the effect of fluoride and chlorhexidine toothpastes on 24-h plaque regrowth.

Short-term methodologies have been developed to screen chemical agents for plaque inhibitory effects. Most measure inhibition of plaque regrowth over several days. A method was described to study agents over 16-24 h periods, although some difficulties with the index used were reported. The aim of this study was to determine whether more conventional plaque scoring methods could be used. These 2 crossover studies measured plaque regrowth over 24 h in 20 subjects and in response to single brushings with either a chlorhexidine and minus active toothpaste or to a fluoride toothpaste product and water. Significantly less plaque had reformed after brushing with the chlorhexidine toothpaste compared with its control and with the fluoride toothpaste compared with water. 18 subjects participated in both studies and using their data for an interstudy comparison, less plaque developed with the chlorhexidine compared with the fluoride toothpaste. These studies had the advantage that longer-term trials already demonstrated the same differences. This permits one to conclude with some certainty that the 24-h plaque regrowth study design, using conventional measures of plaque accumulation, could be a useful and rapid method of screening potential plaque inhibitory agents and formulations.

Anti-Infective Agents, Local↗

PubMed1995

The use of planimetry to record and score the modified Navy index and other area-based plaque indices. A comparative toothbrush study.

Many plaque-scoring methods are based on a subjective assessment of the amount of tooth surface covered by plaque or the presence or absence of plaque at specific sites. The 2x modified Navy plaque index is an example of the latter and requires chairside decisions from 9 zones of all buccal and lingual tooth surfaces, i.e., up to 576 for a complete dentition. The present study describes a procedural modification to the index, whereby plaque is recorded using an established planimetric plaque area method. Scoring is then performed using an overlay away from the clinic. To test the method, plaque-area measurements were made during a 30-subject, crossover study to compare plaque removal following single toothbrushings with 3 different types of manual toothbrush. Consistent with many such studies, no significant differences in plaque removal were noted between the brushes. The method was found quick and simple at the chairside, provided a permanent record of plaque distribution and could be analysed by clinical or nonclinical personnel under ideal conditions. The same method could be employed for other plaque indices based on area or site subjective decisions.

Cross-Over Studies↗

PubMed1995

An approach to efficacy screening of mouthrinses: studies on a group of French products (I). Staining and antimicrobial properties in vitro.

There is a large and increasing number of oral hygiene products available to the general public. As such, it is difficult to demonstrate efficacy for all in long-term home-use studies. The aim of this project was to determine whether screening studies could position the activity and efficacy of a number of antiseptic mouthrinses, available in France, by comparison with an established product. This study reports the experiments in vitro. The products under test were, 4 containing chlorhexidine (Eludril, Hibident, Parodex and Prexidine) with Hibident considered the positive control, one containing cetylpyridinium chloride (Alodont) and one containing hexetidine (Hextril). The 1st study determined the antibacterial profile of the chlorhexidine products against a panel of oral bacteria using an agar dilution method. The 2nd study recorded, by optical density, the propensity of all products to induce tea staining on clear acrylic specimens. The maximum inhibitory dilution (MID) of the chlorhexidine products against the test organisms, once adjusted for initial concentration differences, were essentially similar. One exception was Eludril which had an increased MID against Capnocytophaga sputigena, an organism normally less sensitive to chlorhexidine. Hibident and Prexidine produced expected levels of tea staining; that produced by Parodex was lower than the expected. Staining by Eludril was little different than water controls suggesting markedly reduced availability of chlorhexidine in this product.(ABSTRACT TRUNCATED AT 250 WORDS)

Acrylic Resins↗

PubMed1995

An approach to efficacy screening of mouthrinses: studies on a group of French products (II). Inhibition of salivary bacteria and plaque in vivo.

The aim of this study was to determine the value of screening studies to assess the efficacy of antiseptic mouthrinse products relative to proven products. The products tested were 6 antiseptic mouthrinses available in France. 4 contained chlorhexidine (Eludril, Hibident, Parodex and Prexidine) with Hibident considered the positive control. 1 product contained cetylpyridinium chloride (Alodont) and 1 hexetidine (Hextril). Saline was used as the negative control. The 1st study assessed the persistence of action of the products by recording salivary bacterial counts before and up to 7 h after single rinses. The 2nd study measured the inhibition of plaque regrowth, from a zero baseline, in the absence of tooth-brushing over a 4-day period. Both studies used blind randomised crossover designs balanced for residual effects. Salivary bacterial count reductions with time were highly significantly greater for Parodex to 5 h and Hibident and Prexidine to 7 h; There were no significant differences between the latter three chlorhexidine rinses except at 3 h, when decrements were significantly less with Parodex. Despite a mean trend in favour, Alodont, Eludril and Hextril were not significantly different from saline. Plaque inhibition by area and index was highly significantly different between products. Hibident, Parodex and Prexidine showed similar plaque inhibition and were significantly more effective than all other rinses. Eludril and Hextril were significantly more effective than saline but Alodont was not. Taken with the associated study in vitro and published reports on the same or similar products, it is apparent that efficacy of a product cannot be assumed merely because it contains a known active plaque inhibitor.(ABSTRACT TRUNCATED AT 250 WORDS)

Anti-Infective Agents, Local↗

PubMed1995

Residual effect of chlorhexidine gluconate in 4-day plaque regrowth crossover trials, and its implications for study design.

The efficacy of oral hygiene agents in preventing the accumulation of plaque from a zero baseline is conveniently evaluated in the 4-day plaque regrowth model. In many studies a panel of volunteers has been used to compare several agents according to a highly efficient Latin square based crossover design. Often chlorhexidine gluconate is included as a positive control; there is concern that the effect of this potent agent might persist for longer than the 3-day washout period often employed. To test this hypothesis of residual effect, we put together the evidence relating to possible carryover from 12 studies. The residual effect of chlorhexidine differs from that of an inert rinse such as saline or water. Consequently, a longer washout period, such as 10 days, is preferable. Studies omitting chlorhexidine are worth considering. Designs should be balanced for residual effects, at least from the preceding treatment period; several useful designs with this property are presented.

Chlorhexidine↗

PubMed1995

Analysis of cultivable Porphyromonas gingivalis with trypsin-like protease enzyme activity and serum antibodies in chronic adult periodontitis.

OBJECTIVE: Trypsin-like protease (TLPase) enzyme produced by Porphyromonas gingivalis has been implicated as a virulence factor in the pathogenesis of periodontal disease. The aims of this study were to investigate the relationship between cultivable P. gingivalis, TLPase enzyme activity (BANA hydrolysis) and serum antibody levels against cell sonicate and a purified TLPase antigen from P. gingivalis W50. MATERIALS AND METHODS: Sub-gingival plaque samples were cultured for levels of P. gingivalis together with a chairside analysis of TLPase enzyme activity (Perioscan) from periodontitis and gingivitis sites of adult periodontitis patients. A TLPase from P. gingivalis was purified by gel filtration and ion exchange chromatography from the vesicle fraction for use as a test antigen. RESULTS: Elevated levels of P. gingivalis were found at periodontitis sites, however, there was no correlation with sub-gingival plaque TLPase enzyme activity. Adult periodontitis patients had higher levels of IgG and IgA against cell sonicate and TLPase antigens than did controls. Those patients who were P. gingivalis culture-positive demonstrated an elevated immune response against both cell sonicate and TLPase when compared to P. gingivalis culture-negative patients. Treatment resulted in an improvement of clinical indices and no cultivable P. gingivalis could be recovered from the treated sites and there was a concomitant decrease in IgG levels against the TLPase. There was no significant difference in BANA hydrolysis at gingivitis sites or periodontitis sites after treatment. CONCLUSIONS: Further longitudinal studies are suggested to investigate the role of the TLPase in the response to treatment of chronic adult periodontitis patients.

Adult↗

PubMed1995

Fulminating strongyloidiasis complicating Indian kala-azar.

Infection with Strongyloides stercoralis in an immunocompetent host usually remains unrecognized. Sometimes, however, it may cause serious problems in the immunocompromised host due to its enhanced invasiveness. We present here details of three kala-azar patients with fulminating strongyloidiasis manifested by acute diarrhoea with blood and mucus, severe dehydration, cough and dyspnoea with low peripheral blood eosinophils and filariform larvae of S. stercoralis in faeces. No larvae could be detected in the sputum in spite of radiological evidence of infiltration. The impact of albendazole was dramatic with a disappearance of parasites from the faeces and of pulmonary infiltration and an increase in blood eosinophil count. It is emphasized that S. stercoralis infection in kala-azar patients should be considered a serious infection and treated accordingly.

Adolescent↗

PubMed1995

Evaluation of clinical trials of agents and procedures to prevent caries and periodontal disease: choosing products and recommending procedures.

The prevention of caries, gingivitis and periodontal diseases has been, and still is, a major objective for the dental profession. A large number of products are available to the general public, either over the counter or on prescription, formulated to prevent these diseases. Formulations are also used by professionals for the prevention and treatment of dental diseases. In recommending or using agents for prevention or therapy it is necessary for the practitioner to appreciate whether proof of efficacy is established. Preventive or therapeutic roles of formulations are frequently confused and there is a need to define the often misleading terminology used to describe products. Guidelines are required to enable the dental professional to understand research data and what constitutes proof of efficacy for preventive and/or therapeutic formulations. The guidelines should describe the research methodologies used today, including study design and analysis, ethics, the format of research papers and the relevance of laboratory data to clinical efficacy.

Anti-Infective Agents, Local↗

PubMed1994

Aetiological, predisposing and environmental factors in dentine hypersensitivity.

If the hydrodynamic theory of stimulus transmission across dentine is valid, sensitive dentine has tubules open at the surface and patent to the pulp. Direct and indirect evidence supports this supposition. Factors that result in dentine exposure remove the covering enamel or periodontal tissues (gingival recession). Epidemiological and clinical data for the distribution of exposed cervical dentine indicate that chronic trauma from physical and chemical factors is the most significant aetiological factor. Brushing with a toothpaste may not open dentinal tubules. It is more likely that toothpaste ingredients, when brushed on dentine, would create a smear layer. Exposure of tubules by erosion is probably the major initiator of sensitivity. An increase in our understanding of the aetiological factors involved in dentine hypersensitivity is essential if a sound approach to its management is to evolve. Such information could emanate from epidemiological studies, clinical investigations and laboratory experiments.

Beverages↗

PubMed1994

An 8-year study of changes in oral hygiene and periodontal health during adolescence.

This study reports data collected from a cohort of 405 South Wales adolescents examined at the ages of 11-12, 15-16 and 19-20 years. Dental plaque and gingivitis scores decreased markedly between the ages of 11-12 and 15-16 years, and to a lesser extent between 15-16 and 19-20 years. There was a decrease in the mean depth of the gingival sulcus between the ages of 11-12 and 15-16 years, perhaps reflecting a decrease in false pocketing and gingival oedema associated with puberty and tooth eruption. Conversely, there was an increase in the mean depth of the gingival sulcus between the ages of 15-16 and 19-20 years, possibly indicating the initiation of periodontal breakdown and the appearance of true pocketing. Gender was found to be an important determinant of the level of oral hygiene practised, the boys having consistently poorer oral hygiene than did the girls. At the commencement of adolescence this was not reflected in higher gingivitis scores, but by the age of 15-16 years the boys exhibited significantly more gingivitis than did the girls.

Adolescent↗

PubMed1994

Dose response of chlorhexidine against plaque and comparison with triclosan.

The optimum dose of chlorhexidine delivered by mouthrinse, which balances efficacy against local side-effects, is generally considered to be in the region of 20 mg 2 x daily. Unfortunately, there have been few dose-response studies for chlorhexidine mouthrinses and for these, only limited details are published. The aims of this study were to determine the dose response of chlorhexidine to plaque inhibition and position a 0.1% triclosan rinse within this model. 28 subjects took part in this 7-treatment, double-blind, randomised cross-over 4-day plaque regrowth study. The rinses were 0.01%, 0.05%, 0.1% and 0.2% chlorhexidine, 0.1% triclosan and minus active controls for chlorhexidine and triclosan. On day 1 from a zero plaque baseline, volunteers suspended tooth-cleaning and commenced supervised 2 x daily rinsing with 10 ml volumes of the allocated rinses. On Day 5, plaque was scored by index and area. Treatment differences between the 7 rinses were highly significant. A clear dose-response pattern was seen for chlorhexidine with mean plaque scores decreasing with increasing dose. Even at 0.01%, chlorhexidine showed considerable and significant plaque inhibition compared to control. Triclosan at 0.1% showed limited plaque inhibition and less than 0.01% chlorhexidine. The findings of this study suggest that consideration could be given to low concentration chlorhexidine rinses as adjuncts to oral hygiene.

Adult↗

PubMed1994

Comparison of 2 chlorhexidine mouthwashes on plaque regrowth in vivo and dietary staining in vitro.

Until recently, the few available chlorhexidine mouthrinse products have been 0.2% formulations. However, concentrations of 0.12% chlorhexidine appear as effective as 0.2%, if the volume of the rinse is increased to 15 ml. Since the mere incorporation of chlorhexidine in a formulation does not guarantee availability of the antiseptic, it would seem reasonable to evaluate or compare all products. This is particularly the case when other ingredients, such as fluoride are added. The 1st study compared the effect of a 0.12% chlorhexidine rinse with a 0.12% chlorhexidine/0.022% sodium fluoride rinse for effects on plaque regrowth. The study was a 7-day, blind, randomised, 2-cell cross-over design with a baseline control run in period, in which 18 subjects participated. Both chlorhexidine products significantly reduced plaque compared to control but the chlorhexidine fluoride rinse was less effective than the chlorhexidine only rinse. The 2nd study assessed the propensity of the chlorhexidine rinses to induce dietary staining in vitro. For the chlorhexidine fluoride rinse, this was less than the other 0.12% rinse and a commonly used 0.2% product. The data in vivo and in vitro suggest reduced chlorhexidine availability from the chlorhexidine fluoride product which appears to cause some loss of efficacy.

Chlorhexidine↗