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The aim of this study was to identify the level of shared learning on a Bachelor of Medical Science in Dental Technology (BMedSci) course at the University of Sheffield, School of Clinical Dentistry. A summative evaluation of the course was carried out, using semi-structured nominal group interviews. BMedSci students, BDS students and recent graduates were questioned and their answers analysed to identify shared learning activities. The results revealed that different levels of shared learning opportunities occurred within the different departments which delivered the course modules. Shared learning was viewed favourably by the students. It has the potential to maximise the use of resources and offers the opportunity for developing an integrated dental team.

Background/aims: This study aimed to investigate the cytokine IL-1beta and its receptor antagonist IL-1ra in gingival crevicular fluid (GCF), in patients with adult periodontitis., Method: A total of 40 GCF samples were harvested from 10 subjects with moderate to severe adult periodontitis and 10 healthy controls. Subjects were selected from both genders, with all the upper anterior teeth present, and with no relevant systemic illness, pregnancy or recent medication. All subjects were non-smokers and had not received any periodontal therapy within the preceding 3 months. Deep bleeding sites, deep non-bleeding sites and healthy sites were investigated in relation to upper anterior teeth. Clinical measurements were recorded for each site, after obtaining a GCF sample. IL-1beta and IL-1ra were quantified using new commercially available ELISA kits (Quantikine), and could be detected in all samples., Results: The mean concentration for IL-1beta was 0.11 (SD 0.14) pg/microl for bleeding periodontitis sites, 0.04 (0.05) pg/microl for non-bleeding periodontitis sites, and 0.01 (0.03) pg/microl for healthy sites (p<0.001). In contrast, the mean concentration for IL-1ra was 6.99 (9.78) pg/microl for healthy sites, 0.59 (0.44) pg/microl for non-bleeding periodontitis sites, and 0.44 (0.36) pg/microl for bleeding periodontitis sites (p<0.001, except for comparisons between bleeding and non-bleeding periodontitis sites, p>0.05). For healthy sites, a strong inverse relationship was found between IL-1beta and IL-1ra levels in GCE., Conclusions: The results suggest a strong relationship between the severity of adult periodontitis and the increasing GCF levels of IL-1beta and decreasing levels of IL-1ra.

A series of 3-arylquinolones was prepared and evaluated for their ability to act as gonadotropin releasing hormone (GnRH) antagonists. A variety of substitution patterns of the 3-aryl substituent are described. The 3,4,5-trimethylphenyl substituent (23h) was found to be optimal.

The dog GnRH receptor was cloned to facilitate the identification and characterization of selective nonpeptide GnRH antagonists. The dog receptor is 92% identical to the human GnRH receptor. Despite such high conservation, the quinolone-based nonpeptide GnRH antagonists were clearly differentiated by each receptor species. By contrast, peptide antagonist binding and functional activity were not differentiated by the two receptors. The basis of the differences was investigated by preparing chimeric receptors followed by site-directed mutagenesis. Remarkably, a single substitution of Phe313 to Leu313 in the dog receptor explained the major differences in binding affinities and functional activities. The single amino acid replacement of Phe313 of the human receptor with Leu313 resulted in a 160-fold decrease of binding affinity of the nonpeptide antagonist compound 1. Conversely, the replacement of Leu313 of the dog receptor with Phe313 resulted in a 360-fold increase of affinity for this compound. These results show that Phe313 of the GnRH receptor is critical for the binding of this structural class of GnRH antagonists and that the dog receptor can be "humanized" by substituting Leu for Phe. This study provides the first identification of a critical residue in the binding pocket occupied by nonpeptide GnRH antagonists and reinforces cautious extrapolation of ligand activity across highly conserved receptors.

Recent high profile cases like Wisheart (Bristol babies) has placed healthcare professional autonomy under both ethical and legal scrutiny, reflected by the growing number of civil cases brought by the public. The aim of this paper is to investigate the effect of evidence-based treatment on the legal requirements of consent, when the treatment transcends the therapeutic boundary. The potential effect on the autonomy of healthcare professionals is also discussed. The study revealed that although consent remains the cornerstone of defence in many areas of therapeutic treatment, it is open to significant legal challenge in the grey area between therapeutic evidence-based treatment and non-evidenced-based procedures. Consent remains the cornerstone of defence for therapeutic procedures. However, it is less certain with innovative treatment or procedures that transcend the therapeutic boundaries and are shown to be non-evidence-based.

SAR studies which focused upon the C-6 position of a recently described series of quinolone gonadotropin releasing hormone antagonists are reported. Synthetic access to diverse quinolone-6-carboxamides was achieved via the palladium-catalyzed amino-carbonylation reactions of iodide 4 with various amines. Amides related to 9y were especially potent, functional antagonists of rat and human GnRH receptors.

The pharmacology of endothelin (ET)-1, big ET-1, ET-3, and S6c were characterized in the anesthetized ferret to assess whether this species would provide a new and suitable nonrodent model to be used in characterization of endothelin antagonists. Unlike other species such as dog, rabbit, and rat, the ferret exhibited a dose-dependent pressor response to both ET-1 and big ET-1 with no preceding vasodilatory response. The median effective concentration (ED50) values were 0.047+/-0.009 and 0.469+/-0.003 nmol/kg for ET-1 and big ET-1, respectively. ET-3 and S6c, however, were found to elicit a transient vasodilatory response preceding the pressor response, with ED50 values of 0.23+/-0.09 and 0.18+/-0.03 nmol/kg, respectively. The rank potency of the agonists for the pressor response was found to be ET-1 > S6c > big ET-1 > ET-3. The ET(A)-specific antagonist BQ-123 was shown to block only partially the ET-1 and big ET-1 pressor response with median antagonistic dose (AD50) of 0.24+/-0.11 and 0.015+/-0.005 mg/kg, i.v., respectively, and blockade of the ET(A) receptor did not uncover an ET(B)-induced vasodilation. The dual ET(A/B) antagonist L-754,142 completely antagonized the ET-1 and big ET-1 pressor responses with AD50 values of 0.195+/-0.063 and 0.019+/-0.006 mg/kg, respectively. The ET(B) antagonist BQ-788 blocked the depressor response of S6c entirely but was unable to antagonize the pressor response completely. BQ-123 was shown to antagonize the S6c pressor response partially, suggesting a possible interaction between the ET(A) and ET(B) receptors in the ferret. The unexpected absence of an ET-1-mediated depressor response but the presence of ET-3 and S6c vasodilation in this species supports the theory that there may be subtypes of the ET(B) receptor. These studies demonstrate that the anesthetized ferret provides a suitable model for assessing the physiological potencies of the endothelins and may provide a tool for further understanding of the diversity of the ET(B) receptor.

This study aimed to detect the levels of osteocalcin in gingival crevicular fluid (GCF) from healthy (< or =3 mm sulcus depth and non-bleeding) and diseased sites (> or =6 mm probing depth and bleeding) in subjects with adult periodontitis, in order to further investigate its potential as a possible marker of the disease process. Periodontal probing depths, attachment levels and gingival indices were recorded from one healthy and one diseased site in each of 20 subjects with adult periodontitis. Both GCF accumulated in the periodontal pocket or sulci and GCF flowing into the periodontal pocket or sulci over a three-minute interval were sampled. The amounts of osteocalcin in each GCF sample was determined using immunoassays. A mean of 2.34 ng/site (2.7 microg/ml) osteocalcin was found at diseased sites and a mean of 2.47 ng/site (5.47 microg/ml) was found at healthy sites for the accumulated GCF collection method. A mean of 0.17 ng/ site (2.17 microg/ml) osteocalcin was found at diseased sites and a mean of 0.14 ng/ site (1.85 microg/ml) at healthy sites for the flow method of GCF collection. There were no statistically significant differences between osteocalcin levels in diseased and healthy sites in subjects with adult periodontitis.

This study was designed to identify gender and age-related differences among complete denture referrals from general dental practice to a dental teaching hospital over a 4 year period. Referral rates were calculated according to male/female ratios in the edentulous population. Although more women than men were referred overall, the proportion of males to females referred was similar to that in the edentulous population. Significant gender-related differences in referral patterns were identified, suggesting that edentulous males with complete denture problems, and aged 69 or less, made proportionately less use of hospital services, and proportionately more when aged 70 or over.

The aim of this study was to investigate the difference in subgingival temperature between smokers and non-smokers at different probing depths, and the effect of probing depth on subgingival temperature for smokers and non-smokers. 20 smokers and 20 non-smokers, with adult periodontitis, and retained upper anterior teeth were included. Initially sublingual temperatures were recorded, followed by subgingival temperature, pocket probing depth, and bleeding upon probing measurements at 3 buccal points at probing depths of 2, 3, 4, 5, and 6 mm for each of the anterior teeth. Sublingual temperatures were consistently higher than subgingival temperatures. The subgingival temperature measurements of pockets which bled upon probing, were subtracted from the sublingual temperature to produce temperature differentials (delta T), independent of individual body temperature, that were compared between smokers and non-smokers. The relationship between probing depth and delta T was examined in, and between, smokers and non-smokers for bleeding sites. delta T was found to decrease linearly with the increase of probing depth, suggesting a subsequent increase of subgingival temperature. Smokers were found to have significantly increased delta T(suggesting lower subgingival temperatures) compared to non-smokers, at probing depths of 2, 3, 4, and 5 mm. The differences in delta T for sites 6 mm in depth were not statistically significant between the 2 groups. It is concluded that for maxillary buccal anterior sites, there is a decrease of temperature differentials with an increase of probing depth at bleeding sites for both smokers and non-smokers. Smokers had higher temperature differentials compared to non-smokers, at probing depths of 2, 3, 4 and 5 mm.

Phylloquinone is a lipid soluble vitamin which is an absolute growth requirement for black-pigmented anaerobes, many of which are implicated in the aetiology of periodontal diseases. This cross-sectional study aimed to detect the levels of phylloquinone in GCF from healthy and diseased sites in subjects with adult periodontitis, in order to investigate further its potential role in the disease process. The sample consisted of eighteen patients with adult periodontitis. Periodontal probing depths, attachment levels and gingival indices were recorded from one healthy and one diseased site in each subject. GCF was sampled and the amount of phylloquinone in each sample was determined using reverse-phase high performance liquid chromatography coupled to electrochemical detection. The mean amount of phylloquinone in accumulated GCF from diseased sites was 406 pg/site and 80 pg/site from healthy sites (p=0.013). When the amounts of phylloquinone in GCF were expressed as concentrations the values were 228 ng/ml and 3350 ng/ml for diseased and healthy sites respectively (p=0.084). These findings suggest the levels of phylloquinone in GCF differs in periodontal health and disease in subjects with adult periodontitis. The total phylloquinone at diseased sites may provide the nutritional requirements favouring the growth of black-pigmented anaerobes.

Site-directed interspecies amino acid exchange was used to compare the binding determinants of a novel dual endothelial-angiotensin receptor ligand, L-746,072, with type-1 angiotensin receptor (AT1) selective antagonists on AT receptors expressed in COS cells. These studies suggest that residues on AT receptors which are non-conserved between amphibian and mammalian species play a greater role in subtype selective ligand recognition than for dual receptor ligands. These data also support the hypothesis that a common non-peptide binding site exists within transmembrane domains on peptidergic receptors.

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.

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.

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.

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.

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.

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.

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).

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

Gingivitis was experimentally induced in 8 human subjects using an acrylic overlay to cover the teeth in the experimental area during any oral hygiene procedures. The overlays were used for a period of 3 weeks, after which the subjects received a scale and polish and then practised normal oral hygiene. At regular intervals during the experimental period, mixed saliva was collected for assay of peroxidase activity by spectrophotometric and test-strip procedures and plaque and gingival indices were assessed clinically. A considerable increase in peroxidase activity was observed during the experimental period, which declined after normal hygiene was resumed. This procedure may allow assessment of the progression of gingivitis under experimental conditions.

Current methods of measuring periodontal probing depths at specified sites by clinical means are subject to wide variation both within and between examiners. This paper reports an investigation into the influence of a constant-force periodontal probe on intra- and inter-examiner variability when measuring probing depths. 30 sites in 10 patients with untreated chronic adult type periodontitis were examined by 2 operators, firstly using a standard periodontal pocket probe then with a constant force probe. Neither examiner was aware of the others readings and were thus blind in relation to one another. Comparison of the recordings of the 2 operators using the standard probes showed significant differences between the operators (p less than 0.01) but this difference became insignificant when the constant force probe was used. One operator had a significant variation between his standard and constant force measurements (p less than 0.01), but the other did not. Overall there was a maximum variation of +/- 1 mm in 79.9% of recordings using the standard probe and this agreement was increased to 100% with the use of the constant pressure probe.

The ability of a powered rotary toothbrush to remove 3- and 4-day-old microbial plaque deposits was evaluated in 10 young adults with healthy gingivae. Using a split mouth technique and a cross-over experimental design, the powered brush was compared with a conventional hand brush over a 14-day period. Statistical analysis of the results showed no significant differences between either method of brushing when the whole mouth, maxillary or mandibular arches were compared. Further analysis of the proximal scores again showed no significant differences between the powered brush or handbrush. The majority of the subjects preferred the conventional handbrush to the powered brush.

This present investigation reports on the microbial pattern of subgingival plaque from English and Indian subjects living in the West Midlands of England. Subgingival plaque from healthy and diseased sites was studied using darkfield microscopy. The results indicate that significant differences exist in microbial flora of clinically normal and diseased sites of English as well as Indian subjects. Coccoid cells predominated in healthy sites, with an increase of 21% in the spirochaetes in diseased sites. The ratio of non-motiles to motiles was 1:0.6 in healthy sites, whereas in diseased sites the ratio observed was 1:1.8 in English subjects and 1:3.6 in Indian subjects. Comparison of healthy sites in Indians with healthy sites in English subjects revealed significant differences between numbers of rods (p less than 0.05). Comparing diseased sites of Indians with diseased sites in English subjects revealed significant difference between both cocci (p less than 0.05) and motile rods (p less than 0.01). A positive correlation between chronic inflammatory periodontal disease and spirochaete burden, and a negative one between the disease and coccal burden, was found.

Subjects for the study were 15 patients requiring periodontal surgery in the maxillary posterior quadrants. A split mouth technique with assignment of quadrants by random alternation was used. Assessments were carried out at given time intervals using the Gingival Index, crevicular fluid measurement, Plaque Index and Retention Index. Pain experience following surgery was also noted. Approximately 8 weeks after the initial assessment, periodontal flap surgery was carried out. On the one side debridement was carried out using an ultrasonic scaler, on the other side, hand instrumentation only was used. On the side receiving ultrasonic debridement during surgery, there was an increased rate of healing as measured by the Gingival Index and crevicular fluid. There was no difference in postoperative pain experience, Plaque Index or Retention Index.

Two replicating techniques currently used for scanning electron microscopy were investigated qualitatively and quantitatively. The most accurate and reliable replicating material was an epoxy resin; this was superior to copper plating as the model material, despite some dimensional inaccuracies. The selected method was then used to obtain accurate elastomeric replicas of rodent and human palatal mucosa. Salivary-duct openings, epithelial cell boundaries, desquamating cells and cell-surface micropits were identified. In some areas, coccal organisms could be seen colonizing the epithelial surface.