Biomedical subjects

T F Walsh

Publications and source records attributed to T F Walsh.

At least 37 records · Page 2Linked to original sources

PubMed1997

Subgingival temperature in smokers and non-smokers with periodontal disease.

The purpose of this study was to compare subgingival temperature in a group of smokers to that of a group of non-smokers with similar levels of periodontal disease. 40 adult subjects, 20 cigarette smokers and 20 non-smokers with evidence of adult periodontitis were examined. Subgingival temperature was measured at 6 sites around each of 4 maxillary anterior teeth. Probing depth, and the presence or absence of bleeding was also recorded. In addition, the sublingual temperature was recorded. All sites were classified as diseased or healthy. Healthy sites did not bleed and had a probing depth of < or = 4 mm, diseased sites were any site which had a probing depth > or = 5 mm, or which bled on probing. Mean sublingual and site temperatures were calculated for smokers and non-smokers. Mean temperature differentials (delta T) between the sublingual temperature and the site temperature were calculated for each site. Smokers had a warmer mean sublingual temperature than non-smokers. A significant difference in subgingival site temperature was demonstrated between the smokers and non-smokers, with the mean site temperature being 0.4 degree C warmer in smokers (p < 0.01). When healthy or diseased sites were compared between smokers and non-smokers, smokers also had warmer mean site temperatures than non-smokers for both healthy and diseased sites (p < 0.01). When the mean temperature differentials (delta T) between healthy and diseased sites were compared across each group, significant differences were also found. For healthy sites, the smokers had a mean delta T 0.2 degree C lower (p < 0.01) than the non-smokers, representing warmer sites. In diseased sites however, delta T was 0.3 degree C higher (p < 0.01) in smokers, representing cooler sites.

Adult↗

PubMed1997

The relationship of bone loss observed on panoramic radiographs with clinical periodontal screening.

The aim of this study was to determine the relationship between bone levels observed on dental panoramic tomographs (DPT) and the WHO/FDI recommended periodontal screening technique: the community periodontal index of treatment needs (CPITN). Computer enhancement and digital analysis were used to improve accuracy and reliability. A total of 199 posterior sextants on DPT radiographs from 50 patients (29 female and 21 male) with a mean age of 42 were examined. A statistically significant relationship was found between CPITN and radiographic measurement from the cemento-enamel junction to the alveolar crestal bone margin (A). The relationship between A and CPITN was found to fit the following equation: square root of A = beta 1 + F, where, F is constant and beta 1 is the coefficient corresponding to the i the codes of CPITN. It was concluded that there was a close correlation between the CPITN screening codes and bone loss as measured on the DPT radiograph.

Adult↗

PubMed1997

Renal protection by a dual ETA/ETB endothelin antagonist, L-754,142, after aortic cross-clamping in the dog.

Renal insufficiency is a significant complication that occurs after surgical procedures, requiring cross-clamping of the aorta. The mechanism for this renal dysfunction is currently not known, but studies suggest a potential role of endothelin in mediating the insufficiency. Accordingly, the role of endothelin was assessed using the nonpeptidyl, dual ETA/ETB endothelin antagonist L-754,142 in a model of renal insufficiency in the anesthetized dog induced by cross-clamping the suprarenal aorta for 60 min, followed by 2 h of reperfusion. In vehicle-treated animals (saline, n = 8) after 2 h of reperfusion, plasma [ET-1] increased 66% and renal blood flow (RBF) was reduced by 38% compared with baseline. This decline was associated with an 84% increase in renal vascular resistance and a 54% reduction in GFR (baseline, 46 +/- 5 ml/min; 21 +/- 3 ml/min at 2 h; P < 0.01) and sodium reabsorption (baseline, 6.7 +/- 0.7 microEq/min; 3.0 +/- 0.5 microEq/min at 2 h, P < 0.01). After baseline measurements, pretreatment with L-754,142 at 0.3 mg/kg bolus + 0.1 mg/kg per h continuous infusion (low dose; n = 8) or 3.0 mg/kg bolus + 1 mg/kg per h infusion (high dose; n = 8) initiated 45 min before aortic cross-clamp led to a dose-dependent normalization of RBF and renal vascular resistance within 2 h of cross-clamp removal. GFR was also improved and returned to within 75% of baseline (P < 0.01 versus vehicle) by 2 h of reperfusion with L-754,142 (baseline, 55 +/- 5 ml/min; 42 +/- 5 ml/min at 2 h with the high dose). The improvement of GFR with L-754,142 treatment was associated with a preservation of sodium reabsorption compared with vehicle-treated animals. This study supports a role of endothelin in the pathogenesis of renal insufficiency after aortic cross-clamping and demonstrates that pretreatment with the dual ETA/ETB endothelin antagonist L-754,142 preserves RBF and sodium reabsorption, leading to a significant improvement in GFR.

Acetamides↗

PubMed1996

Pharmacology of L-744,453, a novel nonpeptidyl endothelin antagonist.

L-744,453 ((+/-)3-[4-(1-carboxy-1-(3,4-methylenedioxyphenyl)methoxy)-3,5-diprop ylphenyl methyl]-3H-imidazo[4,5-c]pyridine) is an endothelin (ET) receptor antagonist from a new structural class, the dipropyl-alpha-phenoxyphenylacetic acid derivatives. L-744,453 competitively and reversibly inhibits [125I]-ET-1 binding to Chinese Hamster Ovary cells expressing cloned human ET receptors (K(i)s: hET(A)=4.3 nM; hET(B)=232 nM), and is selective for endothelin receptors compared to other peptide receptors. It is an antagonist of ET-1 stimulated phosphatidyl inositol hydrolysis in rat uterine slices (IC50=220 nM) and exhibits no agonist activity. This compound also inhibits ET-1 stimulated contraction of rat aortic rings with a K(b) value of 50 nM. L-744,453 protects against ET-1 induced lethality in mice after i.v. (AD50=13 mg/kg i.v.) or oral administration. This compound also antagonizes ET-1 induced increases in diastolic blood pressure in conscious normotensive rats (AD50=0.67 mg/kg i.v.) and anesthetized ferrets (AD50=1.6 mg/kg i.v.). L-744,453 is a potent, selective, orally active endothelin antagonist which may be useful in elucidating the role of endothelin in normal and pathophysiological states.

Animals↗

PubMed1996

Clonality of Porphyromonas gingivalis, Prevotella intermedia and Prevotella nigrescens isolated from periodontally diseased and healthy sites.

Black-pigmented anaerobes have been implicated as major pathogens in the aetiology of adult periodontitis but these organisms are also found in healthy sites. This study aimed to examine the relationship between genotypes of black-pigmented anaerobes and disease status of periodontal sites using restriction endonuclease analysis (REA) and ribotyping. The main black-pigmented species recovered from sites were Porphyromonas gingivalis, Prevotella intermedia and Prevotella nigrescens. Each of the 58 subjects investigated harboured distinct genotypes of these three species. Most subjects appeared to be colonized by a single genotype of P. gingivalis and Pr. intermedia, whereas multiple types of Pr. nigrescens colonized many individuals. Plasmids were only found in a few Pr. nigrescens strains. No association was found between the disease status of sites and any specific or group of genotypes of either species or presence of a plasmid. Since the same genotypes of P. gingivalis, Pr. intermedia and Pr. nigrescens were found at both diseased and non-diseased sites in a subject, adult periodontitis is not explained by the presence of specially virulent clones of these organisms. Their role in periodontitis, therefore, is likely to be opportunistic.

Adult↗

PubMed1996

Mouthrinses as adjuncts in periodontal therapy.

Periodontal diseases are a group of related inflammatory disorders, initiated by dental plaque and causing destruction of the supporting structures of the teeth. Although the inflammatory response is a fundamental defence mechanism against bacterial infection, its persistence over a long period of time may extensively damage the periodontal tissues: cementum, alveolar bone, periodontal ligament and dentogingival tissues. These disorders, despite recent improvements in oral health are still a major cause of tooth loss in patients over 35 years of age.

Adult↗

PubMed1995

The effect of irrigation with chlorhexidine or saline on plaque vitality.

24 adult patients suffering from Adult periodontitis were assigned to 4 groups: the 1st rinsed for 1 min with 0.2% chlorhexidine gluconate (CHX); the 2nd group were irrigated for 15 s with 0.2% CHX in a pulsed oral irrigator; the 3rd group rinsed for 1 min with saline and the 4th group were irrigated for 15 s with saline. Plaque vitality was measured after the 4 experimental procedures, using the method described by Netuschil et al. and scored using the method described by Rundegren et al. The results showed that a single rinse or irrigation with 0.2% CHX solution decreased the % of viable micro-organisms, but the vitality of the bacteria remained unchanged in saline groups. Statistical analysis indicated that irrigation with CHX was more effective at reducing plaque vitality than rinsing with CHX.

Adult↗

PubMed1995

Comparison of digitised and visual plaque vitality measurement.

Plaque samples from 12 patients suffering from adult periodontitis (8 male, 4 female), aged 32-58 (mean age 44.3) years were stained using the technique of vital fluorescence described by Netuschil and co-workers. The proportions of vital plaque was then assessed by 2 techniques: the visual methods previously described and by an image capture system linked to a computerised image programme. A total of 94 plaque samples were included in the study. Analysis of the data from the 2 sets showed that there was no significant difference between the two methods (p = 0.26).

Adult↗

PubMed1995

Characterisation of black-pigmented anaerobes isolated from diseased and healthy periodontal sites.

Prevotella intermedia has recently been re-defined and a new species, Prevotella nigrescens has been proposed. However, there is little data available on the incidence of these new species in periodontal health or disease. Black-pigmented anaerobes isolated from diseased and healthy subgingival sites were identified by serotyping, SDS-PAGE and physiological tests. In adult periodontitis subjects, 64% of active sites, 35.7% of inactive sites and 38.5% of healthy sites yielded black-pigmented anaerobes. Of these, Porphyromonas gingivalis was found in 11% of active and 5% of healthy sites in diseased patients, Prevotella intermedia in 15.5% of active and 20.5% of healthy sites, Prevotella nigrescens in 37.7% of active and 11.5% of healthy sites and Prevotella denticola in 3% of active and 1% of healthy sites. In healthy subjects, 50% of sites yielded black-pigmented anaerobes. P. gingivalis was not found in healthy subjects but P. intermedia was found in 18% and P. nigrescens in 31% of sites. SDS-PAGE proved to be a useful method for routinely differentiating P. intermedia and P. nigrescens and two sub-types of the latter species were detected on the basis of band pattern. Only one P. nigrescens sub-type was found in any given individual and one type, typified by ATCC 25261, was more commonly found in deep pockets. However, overall both P. nigrescens and P. intermedia as species were just as frequently found at healthy sites as diseased sites. Thus, these species, in contrast to P. gingivalis, appear to be common commensals but they may act as opportunistic pathogens.

Adult↗

PubMed1995

The effect of a single application of subgingival antimicrobial or mechanical therapy on the clinical parameters of juvenile periodontitis.

Twenty-six (26) patients, 18 female and 7 male, aged 16 to 25 years (mean age 19.03 +/- 2.2 years) previously diagnosed as suffering from localized juvenile periodontitis were randomly assigned to one of the following treatment groups: 9 patients acted as controls; 8 received subgingival chlorexidine gel; and 9 had subgingival tetracycline paste application. All treatment modalities resulted in a pronounced improvement in PI, GI, and GI-S by 12 weeks (P < 0.001). The mean probing depths also decreased, but there were no significant differences found between the three groups. However, when the interproximal sites of the 3 groups were examined separately from the buccal and lingual sites, it was found that there was a significant (P < 0.05) difference between the probing depths, with the control group showing the greatest reduction of 2.58 mm and the chlorhexidine group showing the least reduction of 1.37 mm. It was concluded that a single application of topical subgingival tetracycline did not result in any short-term improvement over that achieved by standard non-surgical therapy in the clinical parameters of these localized juvenile periodontitis patients.

Administration, Topical↗

PubMed1994

Influence of a single application of subgingival chlorhexidine gel or tetracycline paste on the clinical parameters of adult periodontitis patients.

The clinical effects of subgingivally placed 1% chlorhexidine gel (w/w) and 40% tetracycline (w/w) paste in periodontal pockets of 22 adult periodontitis patients were studied. The 2 agents were applied following scaling and root planing in pockets exceeding 4 mm. The patients were randomly divided into 3 groups: (a) scaling and root planing (SCRP) only, the control group; (b) corsodyl gel+SCRP; (c) Tetracycline paste+SCRP. Gel or paste were gently applied using a syringe with a blunt needle until the selected pocket was overfilled. Evaluations were made of clinical parameters including the plaque index (PI), gingival index (GI), bleeding index (GI-S), probing pocket depths, probing attachment levels and position of the gingival margin. The results suggested that all the treatment modalities were effective in producing statistically significant improvements in clinical parameters. It was concluded that the conventional treatment modalities were essential in the treatment of periodontal diseases, but in view of the structure of the periodontal pocket and adjacent complex root surface, subgingival drug application in certain cases, might also provide adjunctive improvement.

Administration, Topical↗

PubMed1994

Ethanol and pH levels of proprietary mouthrinses.

This study measured the pH and alcohol (ethanol) content of a number of proprietary mouthrinses available for purchase by the general public, as well as assessing the influence of the alcohol content on police exhaled air analysis (breathalysing) procedures. The majority of the mouthrinses were acidic, some with a pH as low as 3.40. Only one was found to be alkaline and one near neutral in pH. The ethanol content varied from 0 to 27 per cent. The effect of the alcohol content on the results of the exhaled air analysis were transient and would be unlikely to influence any legal proceedings.

Adult↗

PubMed1993

Rationale and techniques of non-surgical pocket management in periodontal therapy.

Traditional views on pocket instrumentation in periodontal therapy have centred upon the thorough scaling and planing of root surfaces, which aim to remove all calculus and substantial amounts of 'necrotic' and 'contaminated' cementum. The lack of scientific evidence for removing calculus in periodontal therapy, was highlighted by Frandsen and recent studies have also questioned the need for extensive root planing to remove 'substantial' amounts of cementum. The need for some degree of pocket instrumentation during periodontal therapy however, is beyond doubt, as clinical studies on the efficacy of nonsurgical periodontal treatment published during the last decade have clearly shown. A review of this important topic is therefore timely and this paper aims to elucidate some of the concepts which are currently the subject of debate. A resume of the formation and characteristics of the subgingival environment is a necessary starting point.

Dental Cementum↗

PubMed1993

Pulsed oral irrigation in the management of inflammatory periodontal diseases.

While subgingival scaling and root planing are effective at removing plaque, the use of periodic subgingival irrigation with a antimicrobial solution could be a useful adjunct. This paper initially discusses the management of inflammatory periodontal diseases in general, covering current mechanical therapy and chemical antimicrobials, before describing pulsed oral irrigation in more detail.

Chlorhexidine↗

PubMed1992

Clinical effects of pulsed oral irrigation with 0.2% chlorhexidine digluconate in patients with adult periodontitis.

The aim of this study was to investigate the effects of using 0.2% Chlorhexidine digluconate in an pulsated jet irrigator by patients as part of their daily dental home-care measures. After initial assessment, 16 patients diagnosed as having adult periodontitis received scaling and polishing together with advice on the subgingival use of a pulsated jet oral irrigator with which they were supplied. 8 patients having 293 active sites with probing depths equal to or in excess of 4 mm used 0.2% chlorhexidine digluconate (CHX) in the oral irrigator, 2 x daily for 56 days. The other group of 8 patients with 253 active sites over 4 mm used a placebo as the irrigating solution. A modified dichotomous plaque index (MPI), gingival bleeding index (GBI) and probing pocket depths (PPD) were assessed on days 0, 28 and 56. Within-group comparisons showed that the CHX regime reduced MPI, GBI and PPD significantly but that the placebo group (PG) only achieved a significant reduction in the PPD. Between-group comparisons showed that the use of 0.2% CHX as an irrigant was significantly more effective than the placebo solution at reducing all the clinical parameters studied. The patients found the oral irrigator easy and pleasant to use, although all the CHX group developed staining to a varying extent. This double blind study demonstrated that 0.2% CHX used 2 x daily in an oral irrigator was effective at reducing plaque deposition, periodontal inflammation and probing pocket depths. The effects of using lower concentrations of chlorhexidine digluconate in this regime need to be investigated.

Adult↗

PubMed1991

A new method to assess damaging effects on the gingival tissues of non-surgical instrumentation.

A method of assessing the damaging effects of non-surgical instrumentation was developed. To test the technique, the effect of cavitational activity in the water supply of an ultrasonic scaler was investigated in an in vivo situation. Using a replication technique for the scanning electron microscope, it was shown that the water supply of the ultrasonic scaler caused superficial disruption of the surface of the gingiva, distant from the area of damage caused by mechanical contact. The results indicated that further investigations of this phenomenon using the technique were required.

Dental Scaling↗

PubMed1991

Scanning electron microscopic investigation of changes in the dentogingival area during experimental gingivitis.

The purpose of this study was to investigate the changes that occur in the dentogingival area during experimental gingivitis using a replication technique and scanning electron microscopy (SEM). The upper 1st premolars of 20 subjects were examined prior to plaque accumulation, after plaque had become clinically visible and after 3 weeks plaque accumulation. 3 distinct zones were examined: the tooth surface and its integuments, the gingival crevice and the oral gingiva. Surface features such as perichymata, pits, depressions and cracks were rapidly covered by plaque deposits. These had a raised globular surface with occasional embedded desquamated epithelial cells. Raised plaque colonies were frequently seen by the end of the study. Initially, the gingival crevice presented a layered undulating appearance. With plaque accumulation many desquamating epithelial cells were seen and variations occurred in the width of the crevice. These changes were mirrored in the oral gingiva. The junctional epithelium was initially smooth with occasional pores and emigrating leucocytes. As plaque accumulated, the presence of pores and leucocytes increased and considerable disruption by desquamating epithelial cells was noted. No subject proved resistant to the influence of plaque-induced changes.

Adolescent↗

PubMed1990

Effects of cavitational activity on the root surface of teeth during ultrasonic scaling.

It is recognised that roughness of the root surface will occur during ultrasonic scaling and this has been attributed to the vibrating scaling tip. Although the presence of cavitational activity and acoustic microstreaming forces have been described their effects on the root surface have not been fully evaluated. Utilising an in vitro system of polished gold, it was possible to demonstrate an indentation produced by the scaling tip. However cavitational activity around the tip within the water supply appeared to produce an area of erosion (0.66 +/- 0.3 mm2, 1 SD, n = 10), and the surface appeared pitted. A scanning electron microscope study (SEM) of root surfaces following ultrasonic scaling showed similar areas of erosion. A replica technique was utilised so that control and experimental root surfaces could be observed. Cavitational activity and acoustic microstreaming resulted in a superficial removal of root surface constituents, and this area of removal was measured as 0.7 +/- 0.3 mm2 (1 SD, n = 10), which was not significantly different from that area observed with the gold surface system (p greater than 0.1). It may be concluded that cavitational activity within the cooling water supply of the ultrasonic scaler results in a superficial removal of root surface constituents.

Dental Prophylaxis↗