W G Wade

King's College London, Londinium, England, United Kingdom

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Publications (94)271.87 Total impact

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    ABSTRACT: A collection of Streptococcus sanguinis strains from patients with endocarditis (n = 21) and from the oral cavity (n = 34) was subjected to a multi-locus sequence typing analysis using seven housekeeping genes, carbamoyl-phosphate synthetase (carB), Co/Zn/Cd efflux system component (czcD), d-alanyl-d-alanine ligase (ddl), DNA polymerase III (dnaX), glucose-6-phosphate dehydrogenase (gdh), DNA-directed RNA polymerase, beta subunit (rpoB) and superoxide dismutase (sodA). The scheme was expanded by the inclusion of two the putative virulence genes, bacitracin-resistance protein (bacA) and saliva-binding protein (ssaB), to increase strain discrimination. Extensive intra-species recombination was apparent in all genes but inter-species recombination was also apparent with strains apparently harbouring gdh and ddl from unidentified sources and one isolate harboured a sodA allele apparently derived from Streptococcus oralis. The recombination/mutation ratio for the concatenated housekeeping gene sequences was 1.67 (95% confidence limits 1.25-2.72) and for the two virulence genes the r/m ratio was 3.99 (95% confidence limits 1.61-8.72); recombination was the major driver for genetic variation. All isolates were distinct and the endocarditis strains did not form distinct sub-clusters when the data were analysed using ClonalFrame. These data support the widely held opinion that infecting S. sanguinis strains are opportunistic human pathogens.
    Molecular oral microbiology. 10/2011; 26(5):291-302.
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    ABSTRACT: SummaryA collection of Streptococcus sanguinis strains from patients with endocarditis (n = 21) and from the oral cavity (n = 34) was subjected to a multi‐locus sequence typing analysis using seven housekeeping genes, carbamoyl‐phosphate synthetase (carB), Co/Zn/Cd efflux system component (czcD), d‐alanyl‐d‐alanine ligase (ddl), DNA polymerase III (dnaX), glucose‐6‐phosphate dehydrogenase (gdh), DNA‐directed RNA polymerase, beta subunit (rpoB) and superoxide dismutase (sodA). The scheme was expanded by the inclusion of two the putative virulence genes, bacitracin‐resistance protein (bacA) and saliva‐binding protein (ssaB), to increase strain discrimination. Extensive intra‐species recombination was apparent in all genes but inter‐species recombination was also apparent with strains apparently harbouring gdh and ddl from unidentified sources and one isolate harboured a sodA allele apparently derived from Streptococcus oralis. The recombination/mutation ratio for the concatenated housekeeping gene sequences was 1.67 (95% confidence limits 1.25–2.72) and for the two virulence genes the r/m ratio was 3.99 (95% confidence limits 1.61–8.72); recombination was the major driver for genetic variation. All isolates were distinct and the endocarditis strains did not form distinct sub‐clusters when the data were analysed using ClonalFrame. These data support the widely held opinion that infecting S. sanguinis strains are opportunistic human pathogens.
    Molecular Oral Microbiology 01/2011; 26(5). · 2.65 Impact Factor
  • W G Wade
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    ABSTRACT: The human mouth is host to a diverse collection of microorganisms including bacteria, viruses, fungi and protozoa. Recent advances using molecular methods for the analysis of complex bacterial communities have demonstrated the richness of the oral bacterial biota and the presence of numerous previously undescribed lineages. Dental plaque forms in a structured way with pioneer species able to colonise pellicle-coated enamel followed by secondary plaque formers such as Fusobacterium nucleatum that have the capability of coaggregating with a range of other genera and species. The mature plaque biofilm has many features of multicellular organisms with the constituent organisms cooperating to make nutrients available and resist environmental stresses, and communicating to regulate their overall numbers. Control of the oral microbiota to prevent disease has conventionally been by mechanical means augmented with toothpastes and mouthrinses, but improved knowledge of oral microbial ecology is allowing the development of pre and pro-biotic approaches. Other possibilities include interference with the plaque formation process and the perturbation of bacterial communication networks.
    Journal of dentistry 06/2010; 38 Suppl 1:S21-5. · 3.20 Impact Factor
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    ABSTRACT: Subgingival plaque samples obtained from human subjects with periodontitis, shown to include previously uncultivable members of the phylum Synergistetes, were used to inoculate Cooked Meat Medium (CMM). The presence of Cluster A (uncultivable) Synergistetes was monitored by fluorescent in situ hybridization (FISH) and quantitative PCR (Q-PCR). Cluster A Synergistetes were found to grow in CMM in co-culture with other plaque bacteria and growth was stimulated by the addition of mucin and serum. Plaque samples were also used to inoculate Blood Agar (BA) plates and growth of Cluster A Synergistetes was revealed after anaerobic incubation, by colony hybridization with specific probes. Surface growth on the plates in regions identified by colony hybridization was harvested and used to inoculate fresh plates, thus enriching for Cluster A Synergistetes. Cross-streaks of other plaque bacteria were also used to stimulate Synergistetes growth. In the early passages, no discrete Synergistetes colonies were seen, but after eight passages and the use of cross-streaks of other bacteria present in the enriched community, colonies arose, which consisted solely of Cluster A Synergistetes cells, as determined by 16S rRNA gene PCR and cloning. This is the first report of the successful culture of a member of the uncultivable branch of this phylum.
    Environmental Microbiology 04/2010; 12(4):916-28. · 6.24 Impact Factor
  • S.C. Williams, W.G. Wade
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    ABSTRACT: Aim  The aim of this study was to investigate the prevalence of enterococci in saliva, from within infected root treated teeth, and in British-produced cheeses. An additional aim was to determine if similar enterococcal genotypes were found within these three groups.Methodology  Seventy four samples were collected from the three groups and cultured on Chromocult® enterococci agar. The cultured bacteria were then identified using the Rapid ID 32 Strep kit (bioMerieux). DNA was then extracted from the enterococcal isolates, and genotyping performed by means of repetitive extragenic palindromic (REP) PCR with REP1R-DT and REP-2DT primers. Strains were assigned to clonal types by means of the GelCompar software analysis of REP-PCR profiles.Results  Enterococci were isolated from 8 of 50 saliva samples, and from 4 of 15 root canal samples, and from seven of nine cheese samples. Sixteen isolates were identified as E. faecalis, one isolate was identified as E. faecium, one isolate was identified as E. durans, and one isolate identified as E. avium. REP-PCR revealed nine clonal types within E. faecalis. The same clonal types were found in samples from saliva, from the root canal, and from British-produced cheeses.Conclusions  The prevalence of enterococci in the oral cavity was found to be 12%. The prevalence in the infected previously treated root canal was 27%. Enterococci was isolated from seven out of nine British cheeses investigated. The same clonal types of E. faecalis were recovered from saliva, from in the previously treated infected root canal and from British-produced cheese's. It would be of interest to investigate the prevalence of E. faecalis in the oral cavity from people that do not eat cheese due to the fact of medical reasons or through choice, to see if there is any difference in the prevalence found.
    International Endodontic Journal 03/2010; 43(4):352 - 353. · 2.05 Impact Factor
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    ABSTRACT: The effect of a 0.1 per cent hexetidine mouthwash on the microorganisms associated with aphthae and healthy mucosa in six volunteers was investigated in a cross-over study. No significant differences in total anaerobic, total streptococcal or dextran-producing streptococcal numbers or anaerobe/aerobe ratios were seen before or after either treatment. No differences were seen in the composition of the microflora between aphthous and control sites. No change in the susceptibility of the isolates to hexetidine was seen during the study.
    07/2009; 4(3):181-186.
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    W. G. Wade
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    ABSTRACT: Periodontal disease has been traditionally associated with an anaerobic gram-negative microbiota. However, improvements in sampling handling and culture media have revealed that gram-positive anaerobes belonging to the genus Eubacterium can make up around half of the microbiota in advanced disease. The asaccharolytic species E. brachy, E. nodatum, E. saphenum and E. timidum show significant associations with severe periodontal disease, but are only rarely found in oral health. Antibodies to E. brachy and E. timidum are raised in patients with periodontal disease compared with healthy controls. Studies of the genus are hampered by the poor and slow growth of the majority of species and the indifferent taxonomy of the group. It is estimated that there are at least 20 un-named taxa. 16S ribosomal RNA sequencing has revealed that the oral asaccharolytic Eubacterium species are closely related to the genera Clostridium and Peptostreptococcus and exhibit three distinct lines of descent. Virulence factors produced by these organisms are as yet unknown although one unnamed taxon which is strongly associated with dento-alveolar abscesses has been established in continuous culture and has been shown to exhibit a wide range of aminopeptidase activity.
    07/2009; 9(6):367-370.
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    M. A. Slayne, W. G. Wade
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    ABSTRACT: Asaccharolytic Eubacterium species are strongly associated with advanced periodontal disease. Raised systemic antibody levels to Eubacterium brachv, E. nodatum and E. timidum have been found in periodontitis patients compared to healthy controls using ELJSA and RIA. This study compared antibody profiles in periodontitis patients and controls against oral asaccharolytic Eubacterium species by Western blotting. Whole-cell proteins from strains of E. brachy, E. nodatum, E. timidum and representative strains of five candidate species were separated using PhastSystem SDS-PAGE. The proteins were electroblotted onto nitrocellulose and probed with 23 sera from periodontitis patients and 23 from periodontally healthy age- and sex-matched controls. Antibodies were present to proteins of all strains except E. nodatum but there was no relationship between patterns of antigen recognition and periodontal status.
    07/2009; 7(5):283-286.
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    ABSTRACT: Members of the phylum "Synergistetes" have frequently been detected in the human oral cavity at sites of dental disease, but they have rarely been detected in studies of oral health. Only two oral "Synergistetes" taxa are cultivable. The aims of this study were to investigate the diversity of "Synergistetes" in the oral cavity, to establish whether "Synergistetes" taxa are more strongly associated with periodontitis than with oral health, and to visualize unculturable "Synergistetes" in situ. Sixty samples (saliva, dental plaque, and mucosal swabs) were collected from five subjects with periodontitis and five periodontally healthy controls. Using phylum-specific 16S rRNA gene primers, "Synergistetes" were identified by PCR, cloning, and sequencing of 48 clones per PCR-positive sample. Subgingival plaque samples were labeled with probes targeting rRNA of unculturable oral "Synergistetes" using fluorescent in situ hybridization (FISH). Analysis of 1,664 clones revealed 12 "Synergistetes" operational taxonomic units (OTUs) at the 99% sequence identity level, 5 of which were novel. "Synergistetes" OTU 4.2 was found in significantly more subjects with periodontitis than controls (P = 0.048) and was more abundant in subgingival plaque at diseased sites than at healthy sites in subjects with periodontitis (P = 0.019) or controls (P = 0.019). FISH analysis revealed that unculturable oral "Synergistetes" cells were large curved bacilli. The human oral cavity harbors a diverse population of "Synergistetes." "Synergistetes" OTU 4.2 is associated with periodontitis and may have a pathogenic role.
    Applied and Environmental Microbiology 05/2009; 75(11):3777-86. · 3.95 Impact Factor
  • M.A. Slayne, M. Addy, W.G. Wade
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    ABSTRACT: The effect of the copolymer M239, 144 with and without chlorhexidine on the adherence of oral streptococci to saliva-coated hydroxyapatite was investigated. At 1% w/v M239, 144 reduced the adherence of Streptococcus sanguis NCTC 7863 by 94%. It had a moderate effect on the adherence of other Strep. sanguis strains and a Streptococcus gordonii strain but had no effect on the adherence of Streptococcus oralis or Streptococcus mutans. Chlorhexidine did not influence the anti-adhesive properties of 1% w/v M239, 144.
    Letters in Applied Microbiology 06/2008; 18(3):174 - 176. · 1.63 Impact Factor
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    ABSTRACT: OBJECTIVE: This study was undertaken in order to test the hypothesis that the consequences of tobacco smoking may include increased synthesis of toxic volatile sulphur compounds in diseased periodontal pockets.DESIGN: A cross-sectional, parallel study comparing groups of smokers and non-smokers with periodontitis and the level of volatile sulphur compounds in the gingival sulci of these subjects.PATIENTS AND METHODS: Levels of volatile sulphur compounds were measured in diseased periodontal sites of 12 smokers and 11 non-smokers using a portable sulphide monitor. Anaerobic and aerobic counts of the total cultivable subgingival microflora of both groups were also determined.RESULTS: The percentage of sites per subject with high levels of sulphides (≥10 units) detected in moderate (4–6 mm) and deep (≥7 mm) periodontal pockets was found to be significantly higher in smokers, compared to non-smokers (P= 0.040 and P= 0.005, respectively). No significant difference in the microbiological parameters tested were observed between the two groups.CONCLUSIONS: Increased production of volatile sulphur compounds may represent a further mechanism of increased susceptibility to periodontitis in smokers and also help to explain the reported association between smoking and halitosis.
    Oral Diseases 01/2008; 6(6):371-375. · 2.38 Impact Factor
  • William G. Wade, Martin A. Slayne
    Periodontology 2000 02/2007; 15(1):25 - 31. · 4.01 Impact Factor
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    ABSTRACT: Molecular ecological analysis based on 16S rRNA gene sequence analysis is well established for the characterisation of complex bacterial communities. However, 'universal' PCR primers can introduce biases into the analysis of the species composition of clone libraries because of mismatches between the primer and target organism sequences. In this study, three universal primer sets were compared for the analysis of the microflora in subgingival plaque. Three subgingival plaque samples were collected from two subjects with localised severe chronic periodontitis. Half of each sample was cultured while DNA was extracted from the remaining half and 16S rDNA amplified with universal primer pairs 27F, 1525R (A); 27F, 1492R (B) and 530F, 1525R (C). Amplified genes were cloned, sequenced and identified by comparison with 16S rRNA databases. 137 taxa were identified among 177 isolates and 417 clones sequenced. Of these, 86 were detected only by the molecular technique whereas 26 were found only by culture. Sequences from 81 taxa did not correspond to those of named species and of these, 38 were not represented in the nucleotide databases. 16S RNA genes for these 38 taxa were sequenced and deposited with GenBank. The use of three sets of universal primers allowed the identification of 38 novel bacterial phylotypes. There were marked differences in the composition of the libraries generated by the different primer sets. A combination of molecular and cultural techniques is recommended to maximise the coverage of detection of bacterial taxa in oral samples.
    Oral Microbiology and Immunology 03/2006; 21(1):61-8. · 2.81 Impact Factor
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    ABSTRACT: Periodontitis is the commonest bacterial disease of humans and is the major cause of adult tooth loss. About half of the oral microflora is unculturable; and 16S rRNA PCR, cloning, and sequencing techniques have demonstrated the high level of species richness of the oral microflora. In the present study, a PCR primer set specific for the genera Porphyromonas and Tannerella was designed and used to analyze the bacterial populations in subgingival plaque samples from inflamed shallow and deep sites in subjects with periodontitis and shallow sites in age- and sex-matched controls. A total of 308 clones were sequenced and found to belong to one of six Porphyromonas or Tannerella species or phylotypes, one of which, Porphyromonas P3, was novel. Tannerella forsythensis was found in significantly higher proportions in patients than in controls. Porphyromonas catoniae and Tannerella phylotype BU063 appeared to be associated with shallow sites. Targeted culture-independent molecular ecology studies have a valuable role to play in the identification of bacterial targets for further investigations of the pathogenesis of bacterial infections.
    Journal of Clinical Microbiology 01/2005; 42(12):5523-7. · 4.07 Impact Factor
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    ABSTRACT: The use of culture-independent molecular methods for the characterisation of the oral microflora in health and disease is revolutionising our understanding of the microbial ecology of the mouth. In addition, the use of 16S rRNA gene sequence analysis is allowing more precise identification of oral bacteria compared with that obtained using conventional phenotypic tests. The aim of this study was to use a combination of cultural and culture-independent methods to characterise the microflora in dentinal caries, endodontic lesions and periodontal pockets. Samples were cultured under aerobic and anaerobic conditions and randomly selected isolates were identified by 16S rRNA gene sequence analysis. In addition, DNA was extracted directly from the samples, 16S rRNA genes amplified by PCR and the amplified genes cloned to create Escherichia coli libraries. 3592 clones and isolates were sequenced and identified. 265 taxa, identified to species-level, were represented and belonging to 9 phyla: Actinobacteria, Bacteroidetes, Chloroflexi, Firmicutes, Fusobacteria, Proteobacteria, Spirochaetes, Synergistes and candidate Division TM7. 62 taxa were found in the endodontic samples, 98 in the carious lesions while the periodontal samples were the most species-rich with 161 taxa present. 15 taxa were found in both the caries and endodontic samples, 17 in the caries and periodontal samples and 21 in the endodontic and periodontal samples. Only 4 taxa were found in all three sample sets. In conclusion, the oral microflora is highly species-rich and the bacterial communities associated with the common dental diseases are specific to those diseases.
    International Congress Series 01/2005; 1284:150-157.
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    ABSTRACT: The uncertain taxonomy of oral anaerobic gram-positive bacilli and their generally slow growing nature has limited the understanding of their role in periodontal disease. The current objective was to design and use species-specific oligonucleotide probes to investigate the relationship of selected gram-positive anaerobic bacilli to periodontal disease. Plaque and clinical measurements were collected from 40 patients with periodontitis and from 40 matched controls. Oligonucleotide probes were designed for Bulleidia extructa, Eubacterium nodatum, Mogibacterium timidum and Slackia exigua and used to probe nucleic acids extracted from the samples with a chemiluminescent detection method. Species were quantified as absent or present at low (approximately 10(3)-10(4) cells), medium (approximately 10(4)-10(5) cells) or high levels (approximately 10(5)-10(6) cells). M. timidum and B. extructa were detected in only three and four samples, respectively. The level of both E. nodatum and S. exigua was significantly higher in deep than shallow pockets (Wilcoxon, p < 0.001). The level of E. nodatum, but not S. exigua, was higher in patients than matched controls (Mann-Whitney U, p < 0.03). Using an ordered logistic regression model, the probing depth of the sampled sites had the greatest influence on the level of both species and significant variations occurred between individuals. Bleeding also influenced the levels of both species, with supragingival plaque influencing S. exigua. Both E. nodatum and S. exigua were associated with clinical indicators of periodontal disease.
    Journal of Periodontal Research 08/2004; 39(4):213-20. · 1.99 Impact Factor
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    ABSTRACT: Molecular techniques have revealed many novel, presumed unculturable, taxa in oral infections. The aim of this study was to characterize the bacterial community of the middle and advancing front of carious dental lesions by cultural and molecular analyses. Samples were collected with a hand excavator from five teeth with carious lesions involving dentine. Samples were cultured on blood agar and Rogosa agar incubated in air plus 5% CO(2) and on fastidious anaerobe agar anaerobically. DNA was also extracted directly from the samples and 16S rRNA genes were amplified by PCR with universal primers. PCR products were singularized by cloning, and the cloned inserts and cultured isolates were identified by 16S rRNA gene sequence analysis. We identified 95 taxa among the 496 isolates and 1,577 clones sequenced; 44 taxa were detected by the molecular method alone; 31 taxa were previously undescribed. Only three taxa, Streptococcus mutans, Rothia dentocariosa, and an unnamed Propionibacterium sp., were found in all five samples. The predominant taxa by anaerobic cultivation were the novel Propionibacterium sp. (18%), Olsenella profusa (14%), and Lactobacillus rhamnosus (8%). The predominant taxa in the molecular analysis were Streptococcus mutans (16%), Lactobacillus gasseri/johnsonii (13%), and Lactobacillus rhamnosus (8%). There was no significant difference between the compositions of the microflora in the middle and advancing front samples (P < 0.05, Wilcoxon matched pairs, signed ranks test). In conclusion, combined cultural and molecular analyses have shown that a diverse bacterial community is found in dentinal caries and that numerous novel taxa are present.
    Journal of Clinical Microbiology 08/2004; 42(7):3023-9. · 4.07 Impact Factor
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    J Downes, M Munson, W G Wade
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    ABSTRACT: Six strains of anaerobic, Gram-negative coccobacilli isolated from the root canals of patients with endodontic infections (five strains) and from a deep periodontal pocket (one strain) were subjected to a comprehensive range of phenotypic and genetic tests and were found to comprise a homogeneous group. Following 16S rRNA gene sequence analysis, they were found to be most closely related to Dialister pneumosintes, with 93 % sequence similarity between the two taxa. A novel species, Dialister invisus sp. nov., is proposed. Biochemically, the species is largely unreactive and is asaccharolytic, with only traces of acetate and propionate detected as metabolic end-products. The G+C content of the DNA of D. invisus strains is 45-46 mol%. The type strain is E7.25(T) (=CCUG 47026(T)=DSM 15470(T)).
    International journal of systematic and evolutionary microbiology 12/2003; 53(Pt 6):1937-40. · 2.11 Impact Factor
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    ABSTRACT: Cultural studies have indicated that a subset of the oral microflora is responsible for endodontic infections. Approximately 50% of oral bacteria are unculturable, so it is likely that currently unknown bacteria are present in such infections. In this study, cultural and molecular analyses were performed on the microflora in aspirate samples collected from 5 infected root canals. 16S rDNA sequences from 261 isolates and 624 clones were identified by comparison with database sequences. Sixty-five taxa were identified, of which 26 were found by the molecular method alone. A mean of 20.2 taxa was found in each sample. A new species of Dialister was the only organism present in all 5 samples. Twenty-seven novel taxa were detected, 18 of which belonged to the phylum Firmicutes and 8 to Bacteroidetes. Culture-independent, molecular analysis has revealed a more diverse microflora associated with endodontic infections than that revealed by cultural methods alone.
    Journal of Dental Research 12/2002; 81(11):761-6. · 3.83 Impact Factor
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    ABSTRACT: Several studies have reported adjunctive benefits to scaling and root planing (SRP) of systemic amoxycillin and metronidazole in the treatment of periodontal diseases. To date no comparisons have been made of these antimicrobials alone or in combination. The aim of this study was to compare the adjunctive benefits to SRP of amoxycillin and metronidazole alone and combined. 66 subjects <46 years of age with advanced chronic periodontal disease participated in this randomised, double blind, 4 parallel treatment group designed study. All subjects received quadrant SRP and then were prescribed amoxycillin capsules (250 mg) and metronidazole tablets (200 mg) (AM) or lactate capsules and metronidazole (PM) or amoxycillin and calcium lactate tablets (AP) or lactate and calcium lactate (PP). All medication was 3 of each per day for 7 days. Subgingival plaque samples were obtained and probing depth (PD), loss of attachment (LOA), bleeding on probing (BOP), suppuration (SUPP) and plaque (DEP) were recorded pre-treatment, 1, 3 and 6 months post-treatment. Final group sizes were: AM=15, PM=16, AP=16 and PP=15. PD improved in all groups. Treatment effects were highly significantly different and always greatest in the AM and least in the PP groups. Benefits of PM and AP over PP were also noted. LOA improved in all groups and showed the same highly significant treatment differences, again favouring AM. BOP improved in all groups, particularly in AM compared to the other groups. SUPP improved in all groups and was virtually eradicated in AM with differences among treatments highly significant. DEP changed little in any group and there were no significant differences among groups. Microbiological data showed significant differences in favour of AM compared to PP and PM for total aerobes and anaerobes at 1 month. P. intermedia counts were always lower in active groups compared to PP and reached significance for AM and AP at 1 month and AM and PM at 3 months. The significant differences among treatment groups and the overall trend in the data, in line with other studies, support the considerable adjunctive benefits to SRP of amoxycillin and metronidazole combined in the treatment of advanced chronic periodontal disease.
    Journal Of Clinical Periodontology 04/2002; 29(4):342-50. · 3.69 Impact Factor

Publication Stats

2k Citations
271.87 Total Impact Points

Institutions

  • 1999–2010
    • King's College London
      • Dental Institute
      Londinium, England, United Kingdom
  • 2005
    • Cardiff University
      Cardiff, Wales, United Kingdom
  • 2002
    • The Kings College
      Guymon, Oklahoma, United States
    • British Society for Restorative Dentistry
      Bristol, England, United Kingdom
  • 2001
    • King College
      Guymon, Oklahoma, United States
    • The Forsyth Institute
      Cambridge, Massachusetts, United States
  • 1997
    • University of the West of England, Bristol
      Bristol, England, United Kingdom
  • 1995–1997
    • University of Bristol
      • School of Oral and Dental Sciences
      Bristol, England, United Kingdom
  • 1996
    • Aarhus University
      • Faculty of Health Sciences
      Aars, Region North Jutland, Denmark
  • 1987–1996
    • University of Wales
      • College of Medicine
      Cardiff, Wales, United Kingdom