Frank Abbas

Oral Biofilm Architecture on Natural Teeth

Periodontitis and caries are infectious diseases of the oral cavity in which oral biofilms play a causative role. Moreover, oral biofilms are widely studied as model systems for bacterial adhesion, biofilm development, and biofilm resistance to antibiotics, due to their widespread presence and accessibility. Despite descriptions of initial plaque formation on the tooth surface, studies on mature plaque and plaque structure below the gum are limited to landmark studies from the 1970s, without appreciating the breadth of microbial diversity in the plaque. We used fluorescent in situ hybridization to localize in vivo the most abundant species from different phyla and species associated with periodontitis on seven embedded teeth obtained from four different subjects. The data showed convincingly the dominance of Actinomyces sp., Tannerella forsythia, Fusobacterium nucleatum, Spirochaetes, and Synergistetes in subgingival plaque. The latter proved to be new with a possibly important role in host-pathogen interaction due to its localization in close proximity to immune cells. The present study identified for the first time in vivo that Lactobacillus sp. are the central cells of bacterial aggregates in subgingival plaque, and that Streptococcus sp. and the yeast Candida albicans form corncob structures in supragingival plaque. Finally, periodontal pathogens colonize already formed biofilms and form microcolonies therein. These in vivo observations on oral biofilms provide a clear vision on biofilm architecture and the spatial distribution of predominant species.

Periodontal inflamed surface area: quantifying inflammatory burden

BACKGROUND Currently, a large variety of classifications is used for periodontitis as a risk factor for other diseases. None of these classifications quantifies the amount of inflamed periodontal tissue, while this information is needed to assess the inflammatory burden posed by periodontitis. AIM To develop a classification of periodontitis that quantifies the amount of inflamed periodontal tissue, which can be easily and broadly applied. MATERIAL AND METHODS A literature search was conducted to look for a classification of periodontitis that quantified the amount of inflamed periodontal tissue. A classification that quantified the root surface area affected by attachment loss was found. This classification did not quantify the surface area of inflamed periodontal tissue, however. Therefore, an Excel spreadsheet was developed in which the periodontal inflamed surface area (PISA) is calculated using clinical Attachment Level (CAL), recessions and bleeding on probing (BOP). RESULTS The PISA reflects the surface area of bleeding pocket epithelium in square millimetres. The surface area of bleeding pocket epithelium quantifies the amount of inflamed periodontal tissue. A freely downloadable spreadsheet is available to calculate the PISA. CONCLUSION PISA quantifies the inflammatory burden posed by periodontitis and can be easily and broadly applied.

Treatment of periodontitis improves the atherosclerotic profile: a systematic review and meta‐analysis

AIM Systematic review and meta-analyses to study the robustness of observations that treatment of periodontitis improves the atherosclerotic profile. MATERIAL AND METHODS Literature was searched in Medline-PubMed, Cochrane CENTRAL and EMBASE, based on controlled periodontal intervention trials, including also a non-intervention group. Data were extracted and meta-analyses were performed. RESULTS From 3928 screened studies, 25 trials met the eligibility criteria. These trials enrolled 1748 periodontitis patients. Seven trials enrolled periodontitis patients that were otherwise healthy, 18 trials recruited periodontal patients with various co-morbidities, such as CVD or diabetes. None of the trials used hard clinical endpoints of CVD. However, improvement of endothelial function has been consistently reported. Meta-analyses demonstrated significant weighted mean difference (WMD) for hsCRP (-0.50 mg/l, 95% CI:-0.78; -0.22), IL-6 (-0.48 ng/l, 95% CI: -0.90; -0.06), TNF-α (-0.75 pg/ml, 95% CI: -1.34; -0.17), fibrinogen (-0.47 g/l, 95% CI: -0.76; -0.17), total cholesterol (-0.11 mmol/l, 95% CI: -0.21; -0.01) and HDL-C (0.04 mmol/l, 95% CI: 0.03; 0.06) favouring periodontal intervention. Importantly, periodontitis patients with co-morbidity benefitted most from periodontal therapy; significant WMD were observed for levels of hsCRP (-0.71 mg/l, 95% CI: -1.05; -0.36), IL-6 (-0.87 ng/l, 95% CI: -0.97; -0.78), triglycerides (-0.24 mmol/l, 95% CI: -0.26; -0.22), total cholesterol (-0.15 mmol/l, 95% CI: -0.29; -0.01), HDL-C (0.05 mmol/l, 95% CI: 0.03; 0.06) and HbA1c (-0.43%, 95% CI: -0.60; -0.25). CONCLUSIONS This systematic review and meta-analyses demonstrate that periodontal treatment improves endothelial function and reduces biomarkers of atherosclerotic disease, especially in those already suffering from CVD and/or diabetes.

The periodontium of periodontitis patients contains citrullinated proteins which may play a role in ACPA (anti-citrullinated protein antibody) formation

AIM To determine the presence and location (stroma versus epithelium) of citrullinated proteins in periodontitis tissue as compared to non-periodontitis tissue and synovial tissue of RA patients. MATERIALS & METHODS Periodontitis, healthy periodontal and RA-affected synovial tissue samples were collected in addition to buccal swabs. These samples were stained for the presence of citrullinated proteins using polyclonal (Ab5612) and monoclonal (F95) antibodies. Furthermore, Western blotting with F95 was performed on lysates prepared from periodontal and synovial tissues. RESULTS In periodontitis stroma, increased citrullinated protein presence (80%) was observed compared with control stroma (33%), the latter was associated with inflammation of non-periodontitis origin. Periodontal epithelium always stained positive for Ab5612. Noteworthy, only periodontitis-affected epithelium stained positive for F95. All buccal mucosal swabs and 3 of 4 synovial tissue samples stained positive for both Ab5612 and F95. Western blotting with F95 showed presence of similar citrullinated proteins in both periodontitis and RA-affected synovial tissue. CONCLUSION Within the periodontal stroma, citrullination is an inflammation-depended process. In periodontal epithelium, citrullination is a physiological process. Additional citrullinated proteins are formed in periodontitis, apparently similar to those formed in RA-affected synovial tissue. Periodontitis induced citrullination may play a role in the aetiology of rheumatoid arthritis.

Denaturing Gradient Gel Electrophoresis as a Diagnostic Tool in Periodontal Microbiology

ABSTRACT Bacteria play an important role in the initiation and progression of periodontal diseases and are part of a biofilm, which can contain over 100 different species. The aim of the present study was to show the potential of denaturing gradient gel electrophoresis (DGGE) as a tool for the detection of clinically relevant species and to compare the results of detection by DGGE with those by PCR and culturing. Hybridization of the bands from the DGGE profiles with species-specific probes was developed to confirm the band positions in the marker obtained with reference strains. The sensitivities of DGGE compared to those of cultivation for the detection of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, and Tannerella forsythensis were 100, 100, 88, and 100%, respectively; and the sensitivities of DGGE compared to those of PCR were 100, 90, 88, and 96%, respectively. DGGE as a diagnostic tool could easily be extended to other species, as shown for Treponema denticola, which could be detected in 48% of the samples. Three different groups of A. actinomycetemcomitans serotypes could be distinguished by DGGE (i.e., a group comprising serotypes a, d, e, and f; a group comprising serotype b; and a group comprising serotype c). Amplicons from P. gingivalis and T. denticola migrated to the same position in the gel, and P. intermedia produced multiple bands. In the present study we show that the DGGE profiles represent clinically relevant species which can be detected by hybridization with species-specific probes. With DGGE, large numbers of samples can be analyzed for different species simultaneously, and DGGE may be a good alternative in periodontal microbial diagnostics.

Efficacy of natural antimicrobials in toothpaste formulations against oral biofilms in vitro.

OBJECTIVES To evaluate the antimicrobial efficacies of two toothpaste formulations containing natural antimicrobials (herbal extracts and chitosan) against oral biofilms of different composition and maturational status. METHODS Bacteria from a buffer suspension or fresh saliva were adhered for 2h to a salivary conditioning film and subsequently grown for 16h. Dual-species biofilms were prepared from Actinomyces naeslundii T14V-J1 and Streptococcus oralis J22, whilst multi-species biofilms were grown from freshly collected human saliva. Biofilms were exposed to 25wt% toothpaste supernatants. A chlorhexidine-containing mouthrinse and a buffer were used as positive- and negative-controls, respectively. Antibacterial efficacy was concluded from acute killing, bacterial removal, prevention of bacterial re-deposition and continued killing during re-deposition. RESULTS The herbal- and chitosan-based supernatants showed immediate killing of oral biofilm bacteria, comparable with chlorhexidine. Moreover, exposure of a biofilm to these supernatants or chlorhexidine, yielded ongoing killing of biofilm bacteria after exposure during re-deposition of bacteria to a matured 16h biofilm, but not to a much thinner initial biofilm formed by 2h adhesion only. This suggests that thicker, more matured biofilms can absorb and release oral antimicrobials. CONCLUSIONS Supernatants based on herbal- and chitosan-based toothpastes have comparable immediate and ongoing antibacterial efficacies as chlorhexidine. Natural antimicrobials and chlorhexidine absorb in oral biofilms which contributes to their substantive action.

Periodontal disease and pre-eclampsia: a systematic review

AIM This review evaluates the possible relationship between periodontal disease and pre-eclampsia, a major pregnancy complication. A generalized inflammatory response plays an important role in the pathogenesis of pre-eclampsia. Because periodontal disease is a low-grade inflammatory state, periodontal disease might contribute to the pathogenesis of pre-eclampsia. MAIN FINDINGS AND CONCLUSION A literature search of PubMed, EMBASE and CINAHL until August 2010 revealed 12 eligible observational studies and three randomized-controlled trials (RCTs). It appeared difficult to compare these studies, due to variations in definitions of periodontal disease and pre-eclampsia, timing of periodontal examination and inadequate control for confounding factors. Eight observational studies reported a positive association, while four studies found no association. None of the RTCs reported reductions in pre-eclamptic rate after periodontal therapy during pregnancy. Therefore, it is questionable whether periodontal disease plays a causal role in the pathogenesis of pre-eclampsia. The observed association in eight observational studies might be the result of induction of periodontal disease due to the pre-eclamptic state or it may be an epiphenomenon of an exaggerated inflammatory response to pregnancy. Larger RCTs with pre-eclampsia as the primary outcome and pathophysiological studies are required to explore causality and to dissect biological mechanisms involved.

Periodontitis Prevalence and Severity in Indonesians With Type 2 Diabetes

BACKGROUND The prevalence of diabetes mellitus type 2 (DM2) in Indonesia is high and still rising. Periodontitis is associated with DM2. No study has investigated this association in Indonesia, nor has any study investigated this association using a variety of methods to operationalize periodontitis. The present study compares prevalence and severity of periodontitis in patients with DM2 to healthy controls, using different methods to operationalize periodontitis. METHODS A total of 78 subjects with DM2 and 65 healthy control subjects underwent a full-mouth periodontal screening assessing probing depth, gingival recession, plaque index, and bleeding on probing. Using these measurements, the prevalence and severity of periodontitis was operationalized in various ways. Differences in the prevalence and severity of periodontitis between subjects with DM2 and healthy subjects were analyzed using univariate analyses. In regression analyses, the prevalence and severity of periodontitis were predicted on the basis of DM2 presence, controlling for confounders and effect modification. RESULTS Prevalence of periodontitis was significantly higher in subjects with DM2 compared to healthy subjects, showing odds ratios of 5.0 and 6.1. Likewise, periodontitis severity was significantly higher in subjects with DM2. CONCLUSION Indonesian subjects with DM2 had more prevalent and more severe periodontitis than healthy Indonesian subjects, independent of confounding factors or the methods used to operationalize periodontitis.

Retention of Antimicrobial Activity in Plaque and Saliva following Mouthrinse Use in vivo

The aim of this study was to determine the contribution of plaque and saliva towards the prolonged activity, also called substantivity, of three antimicrobial mouthrinses (Listerine®, Meridol®, Crest Pro Health®), used in combination with a toothpaste (Prodent Coolmint®). Volunteers brushed for 4 weeks with a toothpaste without antimicrobial claims, while during the last 2 weeks half of the volunteers used an antimicrobial mouthrinse in addition to brushing. At the end of the experimental period, plaque and saliva samples were collected 6 h after oral hygiene, and bacterial concentrations and viabilities were determined. The contribution of plaque and saliva towards substantivity was assessed by combining plaque obtained after mechanical cleaning only with plaque and saliva obtained after additional use of an antimicrobial rinse. Subsequently, resulting viabilities of the combined plaques were determined. The viabilities of plaque samples after additional rinsing with mouthrinses were lower than of plaque obtained after mechanical cleaning only, regardless of the rinse involved. Moreover, plaque collected 6 h after rinsing with antimicrobial mouthrinses contained a surplus of antimicrobial activity. Only Listerine showed decreased viability in saliva, but none of the mouthrinses showed any residual antimicrobial activity in saliva. The findings indicate that plaque left behind after mechanical cleaning contributes to the prolonged substantivity of antimicrobial mouthrinses.

The recolonization hypothesis in a full‐mouth or multiple‐session treatment protocol: a blinded, randomized clinical trial

AIM To test recolonization of periodontal lesions after full-mouth scaling and root planing (FM-SRP) or multiple session-SRP (MS-SRP) in a randomized clinical trial and whether FM-SRP and MS-SRP result in different clinical outcomes. MATERIALS AND METHODS Thirty-nine subjects were randomly assigned to FM-SRP or MS-SRP groups. At baseline and after 3 months, probing pocket depth (PPD), plaque index (PlI) and bleeding on probing (BoP) were recorded. At baseline, immediately after treatment, after 1, 2, 7, 14 and 90 days, paper point samples from a single site from the maxillary right quadrant were collected for microbiological analysis of five putative pathogens by polymerase chain reaction. RESULTS FM-SRP and MS-SRP resulted in significant reductions in PPD, BoP and PlI and the overall detection frequencies of the five species after 3 months without significant differences between treatments. Compared with MS-SRP, FM-SRP resulted in less recolonization of the five species, significantly for Treponema denticola, in the tested sites. CONCLUSION FM-SRP and MS-SRP result in overall clinically and microbiologically comparable outcomes where recolonization of periodontal lesions may be better prevented by FM-SRP.