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Biomedical subjects

P S Hull

Publications and source records attributed to P S Hull.

At least 19 recordsLinked to original sources
PubMed2005

Developing dental education in primary care: the student perspective.

A pilot outreach course in restorative dentistry based in community clinics began in 2001. As part of the evaluation, 48 fourth year students completed a questionnaire about their opinions of the new course, and about restorative dentistry clinics in the dental hospital. Time management was the most frequently mentioned gain from outreach. In relation to the dental school, students most often saw the specialised teaching staff as a gain. Outreach was equally or more important for students' confidence in clinical diagnosis of dental caries, treatment planning, direct restorations, communicating with patients, and managing patients, time, and resources. The dental hospital was equally or more important for their confidence in the diagnosis of periodontal disease, root planing, crowns, bridges, dentures, and communicating effectively with laboratory staff. Patients in outreach were seen as different from those at the dental hospital because they were unselected, and had different treatment needs. Meeting course requirements was the most frequent concern about outreach. In relation to the dental hospital, students were most often concerned about the quality of teaching and support available. Outreach and the dental hospital provided complementary experiences and the new course met its educational objectives.

Dental Clinics↗
PubMed2001

Tacrolimus is not associated with gingival overgrowth in renal transplant patients.

BACKGROUND: Cyclosporin A is used extensively to prevent the rejection of allogenic renal transplants. However, it is associated with a variety of undesirable side effects including gingival overgrowth. Tacrolimus (FK506), has been marketed as an effective alternative immunosuppressant to cyclosporin A and recent subjective reports suggest patients taking it complain infrequently of gingival problems. This clinical investigation was undertaken to confirm whether or not tacrolimus adversely affected the gingival health of renal transplant recipients. METHODS: Renal transplant patients (RTPs) under the care of the Renal Transplantation Service at the Manchester Royal Infirmary, who had received a renal allograft at least 18 months earlier, were recruited for this study. All but one of the RTPs had been taking tacrolimus since transplantation. The other had commenced tacrolimus therapy two months after receiving her allograft. A hospital based control group was recruited from non transplanted individuals attending the Turner Dental School, Manchester. Each patient underwent a detailed dental assessment and had dental impressions taken. The extent of gingival overgrowth was determined from plaster models. RESULTS: 25 renal transplant recipients and 26 control patients were included in the study. None of the individuals in either the tacrolimus or control groups had clinically significant overgrowth. The patients in the tacrolimus group with the highest overgrowth scores were those also taking calcium antagonists as treatment for hypertension. CONCLUSION: This study demonstrates that tacrolimus has no adverse effects on the gingival tissues and thus has potential as an alternative immunosuppressant for individuals susceptible to developing cyclosporin A-induced gingival overgrowth.

Adult↗
PubMed2001

The influence of transforming growth factor-beta1 gene polymorphisms on the severity of gingival overgrowth associated with concomitant use of cyclosporin A and a calcium channel blocker.

BACKGROUND: The purpose of this study was to determine whether the prevalence and severity of gingival overgrowth in renal transplant recipients concomitantly treated with cyclosporin and a calcium channel blocker was associated with functional polymorphisms within the signal sequence of the transforming growth factor-(TGF)beta1 gene. METHODS: The extent and severity of gingival overgrowth for 164 renal transplant recipients immunosuppressed with cyclosporin A and concomitantly taking a calcium channel blocker since transplant were entered into the study (86 in Manchester, 78 in Belfast). Two biallelic polymorphisms of the TGF-beta1 gene were studied at position +869, codon 10 (leucine to proline substitution), and position +915, codon 25 (arginine to proline substitution). RESULTS: Subjects who were homozygous for proline at codon 10 had significantly higher overgrowth scores than those who were heterozygous (P= 0.03) or homozygous for leucine (P= 0.01). Subjects who were heterozygous (arginine/proline) at codon 25 had a significantly higher (P= 0.04) gingival overgrowth score than those who were homozygous for arginine. Logistic regression analysis indicated that for codon 25 independent predictors of severe gingival overgrowth were the heterozygous arginine/proline genotype (P= 0.009) and whether the individual was young (P= 0.05). CONCLUSIONS: Polymorphisms in the TGF-beta1 gene influence the expression of gingival overgrowth in renal transplant recipients concomitantly treated with cyclosporin and a calcium channel blocker. The polymorphism in the TGF-beta1 gene at codon 25 represented an independent genetic determinant of severe gingival overgrowth in the susceptible subjects studied.

Adult↗
PubMed2000

The calcium channel blocker used with cyclosporin has an effect on gingival overgrowth.

BACKGROUND/AIMS: To investigate whether the choice of calcium channel blocker, used in conjunction with cyclosporin A, affected the prevalence of gingival overgrowth. METHOD: A cohort of 135 renal transplant recipients who had been medicated with cyclosporin A in combination with either nifedipine (89) or amlodipine (46) since transplant, took part in the study. The inclusion criteria were that eligible subjects had been in receipt of a kidney transplant for at least 12 months, had at least 10 teeth and had not received specialist periodontal treatment. The age, gender, current drug regimen and dosage were recorded for each participant and alginate impressions taken of both arches. The presence and severity of gingival overgrowth were scored from plaster models. RESULTS: A higher proportion (72%) of the amlodipine group were categorised as having gingival overgrowth compared with only 53% of the nifedipine group, chi square=4.5, p<0.05. Logistic regression analysis was used to explore the relationship between the presence or absence of gingival overgrowth (dependent variable) and age, gender, time since transplant, dose of cyclosporin A, centre in which the patient was treated, and the calcium channel blocker used (independent variables). Independent predictors of gingival overgrowth in this multivariate analysis were whether the individual was treated with amlodipine or nifedipine (p=0.01) and whether the individual was young or old (p=0.01). Within the multivariate analysis, the odds ratio for amlodipine to be associated with gingival overgrowth compared with nifedipine was 3.0 (confidence interval 1.3-6.9). CONCLUSIONS: The prevalence of gingival overgrowth in renal transplant recipients maintained on cyclosporin A and nifedipine is lower than those treated with cyclosporin A and amlodipine.

Adult↗
PubMed2000

Reduction in gingival overgrowth associated with conversion from cyclosporin A to tacrolimus.

BACKGROUND: Unsightly gingival overgrowth affects many individuals immunosuppressed with cyclosporin A (CsA). Current management involves repeated periodontal surgery and intensive hygienist support. Tacrolimus is an effective alternative immunosuppressive agent for renal transplantation which does not appear to produce gingival enlargement. AIMS: The purpose of the present study was to monitor the gingival response of 4 renal transplant patients (RTPs), with clinically significant CsA-induced gingival overgrowth, after their immunosuppressive therapy was switched to tacrolimus. METHODS: Intra-oral photographs and alginate impressions were taken both prior to the drug conversion and again, 6 to 9 months later. Gingival overgrowth scores were determined, from plaster models on both these occasions. RESULTS: All of the RTPs experienced significant resolution of their gingival enlargement within the time period studied; however, only one had complete regression. CONCLUSION: It is concluded that conversion of RTPs with gingival overgrowth from CsA to tacrolimus may provide an effective management strategy for this clinical problem.

Adolescent↗
PubMed2000

Phospholipid analogues of Porphyromonas gingivalis.

Porphyromonas has lipids containing hydroxy acids and C16:0 and iso-C15:0 major monocarboxylic acids among others. Nothing is known of its individual phospholipid molecular species. The aim of this study was to determine molecular weights and putative identities of individual phospholipid molecular species extracted from Porphyromonas gingivalis (seven strains), P. asaccharolytica (one strain) and P. endodontalis (two strains). Cultures on Blood-Fastidious Anaerobe Agar were harvested, washed and freeze-dried. Phospholipids were extracted and separated by fast atom bombardment mass spectrometry (FAB MS) in negative-ion mode. Phospholipid classes were also separated by thin layer chromatography (TLC). The major anions in the range m/z 209-299 were consistent with the presence of the C13: 0, C15: 0, C16: 0 and C18: 3 mono-carboxylate anions. Major polar lipid anion peaks in the range m/z 618-961 were consistent with the presence of molecular species of phosphatidylethanolamine, phosphatidylglycerol and with unidentified lipid analogues. Porphyromonas gingivalis differed from comparison strains of other species by having major anions with m/z 932, 946 and 960. Unusually, a feline strain of P. gingivalis had a major peak of m/z 736. Selected anions were studied by tandem FAB MS which revealed that peaks with m/z 653 and 946 did not correspond to commonly occurring classes of polar lipids. They were however, glycerophosphates. It is concluded that the polar lipid analogue profiles obtained with Porphyromonas are quite different from those of the genera Prevotella and Bacteroides but reveal heterogeneity within P. gingivalis.

Anions↗
PubMed1999

Effects of tobacco products on the attachment and growth of periodontal ligament fibroblasts.

BACKGROUND: Cigarette smoking is one of the most significant risk factors in the development and further advancement of inflammatory periodontal disease, however, the role of either nicotine or its primary metabolite cotinine in the progression of periodontitis is unclear. This study aimed to investigate the effects of nicotine and cotinine on the attachment and growth of fibroblasts derived from human periodontal ligament (PDL). METHODS: Primary cultures were prepared from the roots of extracted premolar teeth. Cells were used at both low (P3 to P5) and high (P11 to P13) passage. Cell numbers were determined over 14 days using either the 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) assay or with a Coulter counter. Cultures were exposed to culture medium supplemented with 1) 15% fetal calf serum (FCS) only; 2) 1% FCS only; 3) 1% FCS and nicotine (concentration range 5 ng/ml to 10 mg/ml); or 4) 1% FCS and cotinine (concentration range 0.5 ng/ml to 10 microg/ml). RESULTS: Nicotine significantly (P <0.05, by ANOVA) inhibits attachment and growth of low passage cells at concentrations >1 mg/ml and high passage PDL fibroblasts at concentrations >0.5 mg/ml. Cotinine, at the highest concentration used (10 microg/ml), appeared to inhibit attachment and growth of both low and high passage fibroblasts but this was not statistically significant (P >0.05, by ANOVA). CONCLUSIONS: Tobacco products inhibit attachment and growth of human PDL fibroblasts. This may partly explain the role of these substances in the progression of periodontitis.

Analysis of Variance↗
PubMed1998

Phospholipid molecular species distribution of oral Prevotella corporis clinical isolates.

The aim of this study was to determine the distribution of phospholipid molecular species within Prevotella corporis of oral origin. Phospholipids of fresh clinical isolates were extracted and analysed by fast atom bombardment mass spectrometry (FAB-MS) in negative-ion mode. The major monocarboxylate anion peaks, with putative identification, observed for Prevotella corporis were m/z 241, C(15:0); 255, C(16:0); 269, C(17:1); 277, C(18:3); 279, C(18:2); 281, C(18:1). In the high mass region, major anion peaks putatively identified as individual phospholipid (PL) molecular species of Prevotella corporis were of m/z 677, PG(29:1); 691, PG(30:1); 705, PG(31:1); 706, first isotope peak of PG(31:1); and 707, PG(31:0). Related species have a different distribution of PL analogues. Separation of extracted lipid families by TLC confirmed that phosphatidylethanolamine (PE) and phosphatidylglycerol (PG) are the major polar lipids (PLs) in Prevotella corporis. Thus Prevotella corporis has a unique combination of phospholipid analogues of chemosystematic significance.

Chromatography, Thin Layer↗
PubMed1996

The effect of subgingival calculus on the validity of clinical probing measurements.

OBJECTIVES: The aims of this study were to assess the validity of the WHO 621 probe for the detection of subgingival calculus and to assess the effect of subgingival calculus on the measurement of probing pocket depths and clinical attachment levels. METHODS: Teeth used in the study were designated for extraction under local analgesia. Prior to extraction the clinical detection of subgingival calculus was made with a WHO 621 probe. Probing pocket depths and clinical attachment levels were measured. The location and direction of the gingival margin and probing measurements were marked on the teeth with a fine, sterile pencil and following extraction, permanent reference grooves were cut with a fine, tapered diamond bur. The extracted teeth were stained with Gomori's stain and examined for the presence of calculus, and the pocket depths and attachment levels were measured using a stereomicroscope. RESULTS: There was an 80% agreement between the clinical and laboratory detection of subgingival calculus. There was no systematic difference between clinical and histopathological measurements when calculus was present or absent (P > 0.05). Analysis of variance indicated a random error effect due to the presence of subgingival calculus. CONCLUSION: This study has demonstrated the validity of the WHO 621 probe in detecting subgingival calculus and has shown that subgingival calculus could be a source of error in the measurement of probing depths and clinical attachment levels.

Adult↗
PubMed1995

An assessment of the validity of a constant force electronic probe in measuring probing depths.

Reproducible and accurate measurement of probing depth and attachment levels is important in longitudinal studies and clinical monitoring of patients. The aim of this study was to determine the validity of a constant force electronic probe in comparison with a conventional probe in measuring probing depth. Thirty-three teeth scheduled for extraction from 15 patients were used in the study. Probing depths were measured with a constant force electronic probe and a conventional probe at six sites per tooth prior to extraction. The teeth were extracted, washed, and stained and the actual probing depth measured in the laboratory. The constant force electronic probe showed a consistent systematic bias to under measure pocket depths. The mean difference was 0.48 mm, which was statistically significant (P < 0.01). The conventional probe over measured by a statistically non-significant mean of 0.08 mm (P > 0.05). The measurements with the constant force electronic probe were not affected by the site or the position of the tooth in the mouth. The study demonstrated that the constant force electronic probe under measured the probing depths as determined in the laboratory and was less valid than the conventional probe. However, the validity of probing depth measurements using the constant force electronic probe was clinically acceptable.

Adolescent↗
PubMed1992

The use of the CPITN to monitor the outcome of periodontal treatment in a dental hospital setting.

The Community Periodontal Index of Treatment Need (CPITN) is recommended for monitoring the outcome of periodontal treatment, yet to date there is only one published prospective study that has used the index for that purpose. The aim of the present study was to monitor the outcome of periodontal treatment of 42 patients referred to a consultant periodontist in a dental hospital. The CPITN was recorded at baseline by a single trained examiner. Subsequently, the patients were examined independently by the consultant and a treatment plan formulated. The prescribed treatment was carried out, and a record was maintained of the type of treatment provided and the number of visits involved. The CPITN was recorded again approximately 6 months after baseline by the same trained examiner. Full data were obtained for 36 subjects; most (22 patients) had deep pockets (CPITN, code 4) at baseline, while nine had shallow pockets (CPITN, code 3). Patients with deep pockets at baseline required more complex treatment and more visits (mean 6.2 visits) than patients with shallow pockets, calculus or gingival bleeding (mean 3.5 visits). Nineteen of the 22 subjects with deep pockets at baseline showed a reduction in the number of sextants with deep pockets after 6 months; however, in only 11 of these subjects were the number of sextants with deep pockets reduced to zero. In the light of these findings a modified format for summarising such CPITN data is recommended.

Adolescent↗
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

Identification, and susceptibility to seven antimicrobial agents, of 61 gram-negative anaerobic rods from periodontal pockets.

Sixty-one cultures of Gram-negative anaerobic rods were isolated from deep periodontal pockets of patients with rapidly progressive periodontitis. Isolates were speciated as Bacteroides gingivalis (18 isolates), Bacteroides intermedius (8), Bacteroides oris (1), Bacteroides gracilis (17) and Fusobacterium nucleatum (17). Their susceptibilities, to seven antimicrobial agents, were determined in vitro using a plate dilution technique. Amoxycillin and amoxycillin with clavulanic acid were active against all isolates (MIC less than 1 mg/l) and proved the most effective agents tested. F. nucleatum and B. gracilis showed resistance to erythromycin; F. nucleatum had MIC values ranging from 0.03 mg/l up to 128 mg/l when tested with this, least effective agent. Metronidazole was effective against all isolates except for a few strains of B. gracilis (MIC less than 4 mg/l). Tetracycline hydrochloride and minocycline were active against all isolates except for a few strains of B. gracilis (MIC less than 2 mg/l with both minocycline and tetracycline hydrochloride). Penicillin proved less effective than amoxycillin with regard to inhibition of B. gracilis.

Amoxicillin↗
PubMed1991

Evaluation of acrylic strips containing amoxycillin with clavulanic acid for local drug delivery.

The in vitro release of amoxycillin with clavulanic acid from acrylic strips at initial concentrations of 30, 40 and 50 per cent w/w was monitored using a double-beam ultraviolet spectrophotometer and compared with release of tetracycline hydrochloride. Highest levels of the antibacterial agents were released during the first 24 h period. Therapeutic levels of the drugs continued to be released during the subsequent 9 day period and were shown to be biologically active. Furthermore, for amoxycillin with clavulanic acid, an initial concentration of 40 per cent gave the highest level of release on day 10; while, for tetracycline, 50 per cent provided the highest level of release. Local application of 40 per cent amoxycillin with clavulanic acid incorporated into acrylic strips placed in periodontal pockets in patients with established periodontitis produced a marked change in the subgingival microflora as monitored by dark-field microscopy and cultural techniques. These changes in the subgingival flora were concomitant with elimination of bleeding on probing at the treated sites and were still evident 3 weeks after removal of the acrylic strips. The sensitivity of Bacteroides gingivalis (syn. Porphyromonas gingivalis) and Bacteroides intermedius (syn. Prevotella intermedia) isolated before and after treatment to amoxycillin with clavulanic acid remained unchanged.

Acrylic Resins↗
PubMed1991

Amoxycillin with clavulanic acid and tetracycline in periodontal therapy.

The effects of tetracycline and amoxycillin with clavulanic acid on the clinical parameters and subgingival flora of eight patients with rapidly progressive periodontitis was assessed. Subjects received either tetracycline 250 mg four times daily or amoxycillin 250 mg with clavulanic acid 125 mg three times daily for a period of 2 weeks together with subgingival scaling and root planning. Both treatment regimens produced significant reductions in bleeding on probing and probing pocket depths which were still present 16 weeks after the antibiotic therapy. A significant reduction in the mean percentage of black-pigmented Bacteroides spp., Fusobacterium nucleatum and anaerobic corroding bacilli was also obtained. Both treatment regimens were equally effective in reducing the clinical parameter and altering the subgingival flora. The MIC values for Bacteroides gingivalis (Porphyromonas gingivalis). Bacteroides intermedius (Prevotella intermedia) and F. nucleatum to amoxycillin with clavulanic acid remained constant throughout the period of investigation. The MIC values of these organisms to tetracycline increased.

Amoxicillin↗
PubMed1980

Chemical inhibition of plaque.

Attempts to control plaque by chemical means using enzymes, antibiotics and antiseptics are reviewed. Enzymes such as mucinase, dehydrated pancreas, enzymes of fungal origin, dextranase and mutanase showed limited clinical success despite promising in vitro and animal studies. Side effects from the use of enzymes were observed. Many antibiotics have been used in attempts to control plaque and several have been successful. However, problems exist from the long-term use of such drugs which precludes their routine use as agents for controlling plaque. The biguanide chlorhexidine is the most widely used and investigated method of chemical plaque control. Many studies have been demonstrated that it will successfully control plaque. No toxic side effects have been reported from its long-term use but local side effects such as staining of the teeth do occur. The quaternary ammonium compounds have at present no advantages over the biguanides and require more frequent usage to achieve the same degree of plaque control as chlorhexidine.

Anti-Bacterial Agents↗
PubMed1977

The influence of experimental gingivitis on plaque formation.

The rate of plaque growth was assessed using daily Plaque Index measurements over a 7-day period in eleven dental students with an initial mean Gingival Indes of 1.21 (+/- 0.05). The mean Gingival Index was then reduced to 0.27 (+/- 0.04) and the rate of plaque growth assessed in the same way. Bacterial smears were taken from the teeth at intervals during both experimental periods and percentage counts of various morphological types of bacteria made. The rate of plaque growth was found to be significantly greater when the Gingival Index was high compared with when the Gingival Index was low (P less than 0.001). There was also an earlier development of a complex bacterial flora when the Gingival Index was high. The hypothesis is presented that gingival exudate has no inhibitory action on the formation of dental plaque, but contains substances which enhance bacterial aggregation and the colonization of the tooth surfaces by these aggregates.

Adult↗