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    Marc Quirynen

    AimAlthough the complexity of the oral ecology and the ecological differences between health and disease are well accepted, a clear view on the dynamics in relation to disease is lacking. In this study, the prevalence and abundance of 20... more
    AimAlthough the complexity of the oral ecology and the ecological differences between health and disease are well accepted, a clear view on the dynamics in relation to disease is lacking. In this study, the prevalence and abundance of 20 key oral bacteria was assessed in health and disease and more importantly a closer look was given to the inter‐bacterial relationships.Materials and methodsA blinded microbiological database was analysed in this cross‐sectional, retrospective study. The database was constructed based on microbiological analyses of samples from 6308 patients, with gradations of periodontitis (healthy to periodontitis). Data concerning the abundance of 20 oral bacteria and probing pocket depth were provided.ResultsPorphyromonas gingivalis, Tannerella forsythia, Treponema denticola, Eubacterium nodatum, Porphyromonas micra and Porphyromonas intermedia showed a clear increase in abundance and prevalence with increasing pocket depth. Correlation matrices illustrated that...
    The aim of the present study was to assess the influence of endogenous and local factors on the occurrence of implant failure up to the abutment stage. The study comprised a group of 399 consecutive patients, which represented the total... more
    The aim of the present study was to assess the influence of endogenous and local factors on the occurrence of implant failure up to the abutment stage. The study comprised a group of 399 consecutive patients, which represented the total of patients who had been treated from 1995 to 1997 (with a total of 1263 Brånemark Brån-system implants) at the Department of Periodontology of the University Hospital, Catholic University Leuven. For each patient, the medical history was carefully examined. Data collection and analysis were mainly focused on endogenous factors such as hypertension, osteoporosis, hypo- or hyperthyroid function, chemotherapy, diabetes type I or II, Crohn's disease, some local factors (e.g. bone quality, reason for tooth loss) and breach of sterility during surgery. The reason for tooth loss, smoking habits, radiotherapy and other local bone factors (bone quality and quantity) were also recorded. Implant failures were recorded up to the abutment connection. The present study indicated a success rate until this stage of 97.8%. General factors such as heavy smoking, chemotherapy plus poor bone quality increased implant failure rate. Radiotherapy, limited bone volume and claustrophobia, which led to breaching the strict preoperative rules of asepsis, appeared to be the most relevant local factors for early implant failures.
    The purpose of this study was to evaluate over time the marginal bone level changes around implants installed to treat partial edentulism and to investigate the possible effect of several confounding variables. Consecutive intraoral... more
    The purpose of this study was to evaluate over time the marginal bone level changes around implants installed to treat partial edentulism and to investigate the possible effect of several confounding variables. Consecutive intraoral radiographs taken with the paralleling technique were used. In all, 660 partially edentulous patients ever treated in the departments (248 males; 15-83 years of age) with 1655 implants, which were successfully integrated at abutment connection, were loaded by means of fixed partial prostheses. The observation period starting at abutment connection reached 16 years (mean 5.1). Implants were divided into three groups: 235 implants supported single-tooth crowns, 398 supported implant-tooth connected and 1022 free-standing fixed partial prostheses. Implants were placed in maxilla and mandible, both anteriorly and posteriorly. No significant difference in bone level evolution was predicted between the three groups of implants, either for posterior or for anterior sites. The estimated marginal bone loss for the first 6 months is 0.31 mm/year and after that 0.015 mm/year higher in the maxilla than in the mandible. More bone loss was predicted for the first 6 months when dehiscences existed, when a membrane or a bone graft were used, or when metal/ceramic prosthesis material was applied. Age and gender did not affect the change in bone level. The use of subsequently situated single-implant crowns to restore an edentulous space did not lead to more marginal bone loss than around splinted implants. Based on marginal bone height maintenance, the excellent prognosis of the presently used implants to support restorations in the treatment of partial edentulism was confirmed.
    This in vivo split-mouth randomized controlled trial compared a synthetic bone substitute with a bovine bone mineral to cover bone dehiscences after implant insertion. Fourteen patients received four to six implants to support an... more
    This in vivo split-mouth randomized controlled trial compared a synthetic bone substitute with a bovine bone mineral to cover bone dehiscences after implant insertion. Fourteen patients received four to six implants to support an overdenture. Two comparable dehiscences within the same patient were first covered with a layer of autogenous bone, followed by a layer of either Bio-Oss® (group 1; Geistlich Pharma AG, Wolhusen, Switzerland) or Straumann BoneCeramic® (group 2; Institut Straumann AG, Basel, Switzerland) and sealed by a resorbable membrane. The change in vertical dimension of the defect was measured at implant placement and at abutment connection (6.5 months). Clinical and radiological parameters were evaluated up to 1 year of loading. The vertical size of the defect at surgery was 6.4 ± 1.6 mm for group 1 and 6.4 ± 2.2 mm for group 2 sites, measured from the implant shoulder. After 6.5 months, the depth of the defect was reduced to 1.5 ± 1.2 mm and 1.9 ± 1.2 mm for group 1 and group 2 sites, respectively (p > 0.05). No implants failed during follow-up. Mean marginal bone loss over the SLActive surface was 0.94 mm (group 1), 0.81 mm (group 2), and 0.93 mm (group 3, no dehiscence) after 1 year of loading. Both bone substitutes behaved equally effectively.
    Objective: To test the hypothesis that there are differences in total bacterial counts and capacity for biofilm formation between seven different bracket types. Material and Methods: By means of an in vitro experiment, seven commercially... more
    Objective: To test the hypothesis that there are differences in total bacterial counts and capacity for biofilm formation between seven different bracket types. Material and Methods: By means of an in vitro experiment, seven commercially available bracket systems (Damon [A], Clarity [B], Mystique [C], Speed [D], Victory MBT [E], Micro-loc [F], and Generus [G]) were compared. A total of 25 premolar brackets of each bracket system were incubated in brain heart infusion medium containing the saliva and bacteria of two orthodontic patients. After 72 hours, the amounts of aerobe and anaerobe bacteria were determined by counting the colony-forming units (CFU). The CFU ratio (aerobe/anaerobe) also was calculated, and the black pigmented bacteria were analyzed. Results: Significant differences between the different bracket types in terms of biofilm formation were found. Bracket types can be arbitrarily divided into low, intermediate, and high plaque-retaining brackets. The group with low ad...
    Recent research indicated that periopathogens colonize, besides the pockets, also other niches within the oral cavity including: the soft tissues, the saliva, the tongue, and even the tonsils. Since the supragingival plaque and the... more
    Recent research indicated that periopathogens colonize, besides the pockets, also other niches within the oral cavity including: the soft tissues, the saliva, the tongue, and even the tonsils. Since the supragingival plaque and the bacteria in these niches have a major impact on the ...
    This systematic review verified the usefulness/limitations of static surgical guides during implant surgery in the edentulous maxilla. The PICO question was: "Does the use of digitally generated surgical guides vs conventional... more
    This systematic review verified the usefulness/limitations of static surgical guides during implant surgery in the edentulous maxilla. The PICO question was: "Does the use of digitally generated surgical guides vs conventional techniques affect the following outcomes: surgical complications, implant complications, prosthesis complications, implant survival, prosthesis survival, economics, patient satisfaction, and maintenance intervention?" The electronic searches retrieved 2,588 unique articles from which eventually 36 full-text articles were read for eligibility. Because no randomized controlled clinical trials could be found, the PICO question had to be reformulated, now only looking to the outcome of digitally generated surgical guides without comparison with conventional techniques. Although long-term data are lacking, the outcome of implants placed with a static guide and of the prosthetic reconstruction seems similar to that expected from conventional techniques. Th...
    Although periodontitis has a multi-factorial aetiology, the success of its therapy mainly focuses on the eradication/reduction of the exogenous/endogenous periodontopathogens. Most of the species colonise several niches within the oral... more
    Although periodontitis has a multi-factorial aetiology, the success of its therapy mainly focuses on the eradication/reduction of the exogenous/endogenous periodontopathogens. Most of the species colonise several niches within the oral cavity (e.g. the mucosae, the tongue, the saliva, the periodontal pockets and all intra-oral hard surfaces) and even in the oro-pharyngeal area (e.g., the sinus and the tonsils). This review article discusses the intra-oral transmission of periodontopathogens between these niches and analyses clinical studies that support the idea and importance of such an intra-oral translocation. Based on the literature, the oro-pharyngeal area should indeed be considered as a microbiological entity. Because untreated pockets jeopardise the healing of recently instrumented sites, the treatment of periodontitis should involve "a one stage approach" of all pathologic pockets (1-stage full-mouth disinfection) or should at least consider the use of antiseptics during the intervals between consecutive instrumentations, in order to prevent a microbial translocation of periodontopathogens during the healing period. For the same reason, regeneration procedures or the local application of antibiotics should be postponed until a maximal improvement has been obtained in the remaining dentition. This more global approach offers significant additional clinical and microbiological benefits.
    Recent case reports introduced the term retrograde peri-implantitis as a lesion (radiolucency) around the most apical part of an osseointegrated implant. It develops within the first months after insertion. This retrospective study aimed... more
    Recent case reports introduced the term retrograde peri-implantitis as a lesion (radiolucency) around the most apical part of an osseointegrated implant. It develops within the first months after insertion. This retrospective study aimed to find predisposing conditions for such peri-apical lesions and to evaluate treatment strategies. All single implants (426 in the upper, 113 in the lower jaw, all Brånemark system type) placed at the department of Periodontology of the University Hospital (Catholic University Leuven) were included in this retrospective evaluation to check the incidence of retrograde peri-implantitis. Eventual predisposing factors such as patient characteristics (age, medical history), recipient site (local bone quality and quantity, cause of tooth loss), periodontal and endodontic conditions of neighboring teeth, implant characteristics (length, surface characteristics), and surgical aspects (guided bone regeneration, osseous fenestration, or dehiscency) were considered. Moreover, implants with retrograde peri-implantitis were followed longitudinally to verify their treatment outcome by means of different parameters (Periotest values (PTV), marginal bone level, radiological size of peri-apical defect). Seven implants in the upper (1.6%) and 3 in the lower jaw (2.7%) showed retrograde peri-implantitis, before or at abutment connection. In comparison with successful implants, such peri-apical lesions occurred preferably at sites with a history of an obvious endodontic pathology of the extracted tooth to be replaced. The incidence of retrograde peri-implantitis was significantly higher (P<0.0001) for TiUnite implants when compared with the machined implants (8/80 vs. 2/459). The machined implant surface, however, showed a higher failure rate (6.8%) than the TiUnite implants (2.5%). Failures with machined surfaces preferably occurred at extraction sites of teeth with a history of endodontic pathology or sites adjacent to teeth with an obvious endodontic pathology. No other predisposing factors could be identified. A curettage of the peri-apical lesions and the use of a bone substitute material prevented further progression of such lesions in the upper jaw (implants maintained their marginal bone and low PTV scores). A treatment in the lower jaw was less successful. Within the limitations of a retrospective study, these results seem to indicate that retrograde peri-implantitis is provoked by remaining scar or granulomatous tissue at the recipient site: endodontic pathology of extracted tooth (scar tissue-impacted tooth) or possible endodontic pathology from a neighboring tooth.
    Fractioned irradiation of the oral region may cause xerostomia and an increased infection risk. The aim of this study was to evaluate, in a single blind, cross-over trial, the effectiveness of a test toothpaste containing the... more
    Fractioned irradiation of the oral region may cause xerostomia and an increased infection risk. The aim of this study was to evaluate, in a single blind, cross-over trial, the effectiveness of a test toothpaste containing the lactoperoxidase system, compared to a normal fluoridated toothpaste. Twelve patients with pronounced xerostomia were examined during a 52-day period. The following parameters were observed: plaque and gingivitis index, bleeding on probing, probing pocket depth, attachment level, and quality of subgingival plaque (phase contrast microscopy). The test toothpaste reduced the rate of supragingival plaque formation over a longer period. Furthermore, gingival inflammation was lower in the test group. For the other parameters, time-dependent changes were not significant. This pilot-study demonstrates the efficacy of the lactoperoxidase system administered by a toothpaste, on supragingival plaque control in xerostomic patients.
    European Association of Osseointegration, EAO 22nd Annual Scientific Meeting, Dublin, Ireland 17-19 October 2013
    Leukocyteand platelet-rich fibrin (L-PRF) accelerates wound healing in both soft and hard tissue significantly. Major indications for the use of L-PRF and the step-by-step preparation of L-PRF clots, membranes and plugs, as well as... more
    Leukocyteand platelet-rich fibrin (L-PRF) accelerates wound healing in both soft and hard tissue significantly. Major indications for the use of L-PRF and the step-by-step preparation of L-PRF clots, membranes and plugs, as well as application approaches to open-flap debridement and ridge preservation, were introduced in the first two parts of this article series. In this third part of the series, two treatment approaches to sinus floor elevation will be presented. The first option is the application of the lateral window technique and the use of L-PRF as grafting material. The second approach described below is the transalveolar technique, an alternative to the lateral window technique.
    To evaluate the impact of two non-surgical periodontal treatment modalities on metabolic and periodontal clinical parameters in subjects with type 2 diabetes mellitus (T2DM) and poor glycaemic control and chronic periodontitis. A... more
    To evaluate the impact of two non-surgical periodontal treatment modalities on metabolic and periodontal clinical parameters in subjects with type 2 diabetes mellitus (T2DM) and poor glycaemic control and chronic periodontitis. A randomized controlled clinical trial was conducted. Ninety-three T2DM subjects with glycosylated haemoglobin (HbA1c) > 7% were randomly assigned to one of two groups receiving scaling with root planing in multiple sessions quadrant-by-quadrant (Q by Q) or within 24 hr (one stage). Periodontal parameters, HbA1c, glycaemia blood levels (FPG) and C-reactive protein (CRP) values were assessed at baseline and at 3 and 6 months post-therapy. At 6 months, HbA1c had decreased by 0.48% in the Q by Q group and by 0.18% in the one-stage group (p = 0.455). After therapy, subjects with an initial HbA1c < 9% showed an increase of 0.31% (p = 0.145), compared with a decrease of 0.88% (p = 0.006) in those with an initial HbA1c ≥ 9%. Periodontal parameters improved sig...
    Leukocyte- and platelet-rich fibrin (L-PRF), a 2 generation platelet concentrate, has become of great interest in periodontology (e.g. Castro et al. 2016, 2017), and extra-oral wound healing (e.g. Pinto et al. 2017). The preparation of... more
    Leukocyte- and platelet-rich fibrin (L-PRF), a 2 generation platelet concentrate, has become of great interest in periodontology (e.g. Castro et al. 2016, 2017), and extra-oral wound healing (e.g. Pinto et al. 2017). The preparation of L-PRF is based on a centrifugation process, aiming for a blood clot containing the majority of leucocytes and platelets, without the inclusion of red blood cells (Dohan et al. 2010). This article is protected by copyright. All rights reserved.
    Implant stability is one of the most important factors influencing osseointegration. Using stereolithographical guides for maximizing precision, this study aimed at investigating the relationship between implant stability and bone density... more
    Implant stability is one of the most important factors influencing osseointegration. Using stereolithographical guides for maximizing precision, this study aimed at investigating the relationship between implant stability and bone density derived from computerized tomography analysis. One hundred ninety-five implants were placed in 48 patients using digitally designed stereolithographical surgical guides. Ninety-five implants were placed using a mucosa supported guide and 100 implants were placed using a bone supported guide. Implant stability was measured by means of resonance frequency analysis (RFA) and damping capacity assessment (Periotest, PTV). Bone density (Hounsfield units) was measured at different regions of interest (ROI) and cortex thickness was measured around each implant. Implant stability correlated significantly with the different ROI. The best correlation for RFA was obtained for the spongious bone ROI (r = .64) and PTV best correlated with the coronal cortex dens...
    To compare the clinical and microbiological performance of minimally and moderately rough implants in patients with a history of severe periodontitis. Forty-eight minimally (Turned surface [Tur]) and moderately (TiUnite surface [TiU])... more
    To compare the clinical and microbiological performance of minimally and moderately rough implants in patients with a history of severe periodontitis. Forty-eight minimally (Turned surface [Tur]) and moderately (TiUnite surface [TiU]) rough implants were placed in eighteen patients according to a split-mouth protocol. Marginal bone loss, probing pocket depth (PPD), clinical attachment level (CAL), and bleeding on probing (BoP) were recorded, and microbial samples were analysed by means of quantitative PCR. The amount of bone loss over the 5-year period tended to be lower along Tur when compared with that of TiU surfaces (1.0 versus 1.7 mm, p = .06). Although the clinical outcomes tended to be better for Tur surfaces, there were no significant differences between both surfaces in mean PPD (Tur: 3.1 versus TiU: 4.2 mm, p = .09) or CAL (Tur: 0.5 versus TiU: 1.7 mm, p = .06). More bone loss and deeper pockets were recorded for partially than for fully edentulous patients. The cumulative...
    A classification for peri-implant diseases and conditions was presented. Focused questions on the characteristics of peri-implant health, peri-implant mucositis, peri-implantitis, and soft- and hard-tissue deficiencies were addressed.... more
    A classification for peri-implant diseases and conditions was presented. Focused questions on the characteristics of peri-implant health, peri-implant mucositis, peri-implantitis, and soft- and hard-tissue deficiencies were addressed. Peri-implant health is characterized by the absence of erythema, bleeding on probing, swelling, and suppuration. It is not possible to define a range of probing depths compatible with health; Peri-implant health can exist around implants with reduced bone support. The main clinical characteristic of peri-implant mucositis is bleeding on gentle probing. Erythema, swelling, and/or suppuration may also be present. An increase in probing depth is often observed in the presence of peri-implant mucositis due to swelling or decrease in probing resistance. There is strong evidence from animal and human experimental studies that plaque is the etiological factor for peri-implant mucositis. Peri-implantitis is a plaque-associated pathological condition occurring ...
    The objective of this proof-of-concept study was to investigate the effects of a new guided bone regeneration technique with a tissue engineering approach. This single cohort observational study evaluated the outcome of the leucocyte- and... more
    The objective of this proof-of-concept study was to investigate the effects of a new guided bone regeneration technique with a tissue engineering approach. This single cohort observational study evaluated the outcome of the leucocyte- and platelet-rich fibrin (L-PRF) Block for horizontal bone augmentation in the maxilla. The L-PRF Block is prepared by mixing a particulated biomaterial with chopped L-PRF membranes at a 50:50 ratio and adding liquid fibrinogen to glue all together. Horizontal augmentation was assessed linearly and volumetrically immediately after surgery and 5-8 months later by matching consecutive cone beam computed tomography (CBCTs). Ten patients (mean age of 50.7 years [±17.2]) representing 15 sites with horizontal alveolar deficiencies were included. Superimposition of pre-operative and posthealing CBCT scans showed an average linear horizontal bone gain of 4.6 mm (±2.3), 5.3 mm (±1.2) and 4.4 mm (±2.3), measured at 2, 6 and 10 mm from the alveolar crest, respect...
    The aim of this study was to conduct a systematic review to compare the survival rates between short implants (length < 10 mm) versus standard-length implants (≥ 10 mm) inserted in grafted bone. As secondary outcomes, marginal bone... more
    The aim of this study was to conduct a systematic review to compare the survival rates between short implants (length < 10 mm) versus standard-length implants (≥ 10 mm) inserted in grafted bone. As secondary outcomes, marginal bone loss and survival rates of the implant supported prostheses were also analysed. Randomised controlled trials (RCT) that compared both techniques were searched on three electronic databases till June 2016, a manual search was performed on the bibliography of the collected articles, and the authors were contacted for additional references. The estimates of the interventions were expressed in relative risk (RR), mean implant survival rates and mean differences in marginal bone. Eight RCTs were included in this study. From a total of 458 short implants, 15 failed (mean survival rates = 96.7%), While from 488 regular implants, 13 failed (mean survival rates = 97.3%). The technique did not significantly affect: the implant failure rate (P > 0.05), with RR...
    The oral use of antimicrobial agents embedded in toothpastes and mouth rinses results in an oral microbial massacre with high amounts of dead bacteria in close proximity to few surviving bacteria. It was hypothesized that this provides... more
    The oral use of antimicrobial agents embedded in toothpastes and mouth rinses results in an oral microbial massacre with high amounts of dead bacteria in close proximity to few surviving bacteria. It was hypothesized that this provides the surviving pathogenic bacteria a large amount of dead microbial biomass as a nutritional source for growth (necrotrophy). This study demonstrated the necrotrophic growth of periodontal pathogens in the presence of different dead oral species. In addition, the presence of dead bacteria resulted in an outgrowth of several periodontal pathogens in complex multi-species biofilms. Additionally, upon contact with dead oral bacteria, virulence genes of P. intermedia and P. gingivalis were up-regulated (necrovirulence). This resulted in a more pronounced epithelial cytotoxicity (necrotoxicity). These findings indicate that presence of dead bacteria induce necrotrophy, necrovirulence and necrotoxicity in several oral pathogens.
    Chronic wounds (VLU: venous leg ulcer, DFU: diabetic foot ulcer, PU: pressure ulcer, or complex wounds) affect a significant proportion of the population. Despite appropriate standard wound care, such ulcers unfortunately may remain open... more
    Chronic wounds (VLU: venous leg ulcer, DFU: diabetic foot ulcer, PU: pressure ulcer, or complex wounds) affect a significant proportion of the population. Despite appropriate standard wound care, such ulcers unfortunately may remain open for months or even years. The use of leukocyte- and platelet-rich fibrin (L-PRF) to cure skin ulcers is a simple and inexpensive method, widely used in some countries but unknown or neglected in most others. This auto-controlled prospective cohort study explored and quantified accurately for the first time the adjunctive benefits of topical applications of L-PRF in the management of such refractory ulcers in a diverse group of patients. Forty-four consecutive patients with VLUs (n = 28, 32 wounds: 17 ≤ 10 cm(2) and 15 > 10 cm(2)), DPUs (n = 9, 10 wounds), PUs (n = 5), or complex wounds (n = 2), all refractory to standard treatment for ≥3 months, received a weekly application of L-PRF membranes. L-PRF was prepared following the original L-PRF meth...
    To investigate the influence of various surgical techniques for sinus augmentation on the volumetric changes of graft, membrane and the post-operative discomfort. Eighteen patients in need of bilateral sinus floor elevation (SFE) were... more
    To investigate the influence of various surgical techniques for sinus augmentation on the volumetric changes of graft, membrane and the post-operative discomfort. Eighteen patients in need of bilateral sinus floor elevation (SFE) were assigned to lateral SFE, transcrestal SFE and intralift procedures. CBCT images taken at baseline, 1 week and 6 weeks were analysed for volumetric changes in graft and Schneiderian membrane. Questionnaires were used to analyse post-op discomfort. The overall average graft volume obtained after 1 week was 1.87 cm(3) (range 0.12-4.72 cm(3) ). Volumes decreased after 6 weeks to an overall mean volume of 1.33 cm(3) (range 0.10-4.29 cm(3) - average decrease of 27.6%). After 6 weeks, the amount of graft volume decreased in every treatment option, ranging from -23.13% for the tSFE, over -24.55% for the lSFE, to -33.71% for the IL. Although all treatment options correspond in an increase in Schneiderian membrane volume, no statistically significant correlation...
    More insight into the biological fundamentals of leukocyte platelet-rich fibrin (L-PRF) guided healing is necessary to recommend its application, in particular in deficient bone sites that need to support implants. This study investigated... more
    More insight into the biological fundamentals of leukocyte platelet-rich fibrin (L-PRF) guided healing is necessary to recommend its application, in particular in deficient bone sites that need to support implants. This study investigated the short-term bone healing effect of L-PRF treatment in cylindrical non-critical sized bone defects with 3 mm diameter and 6 mm depth in tibiae of 18 adult male New Zealand White rabbits. After a randomization process, 96 bone defects were prepared and half of them were filled with a L-PRF membrane, while untreated defects in the opposite tibia served as control group. The rabbits were euthanized after 7, 14 or 28 days of healing. The bone healing of the cortical and medullary areas was investigated by micro-CT, while the expression of molecular markers (RUNX2, VEGFA, COL1A2 and BMP2) was assessed by qRT-PCR. Treatment with L-PRF did not affect the micro-structural bone characteristics of the repaired bone tissue, except for a decrease in the trab...
    L-PRF (leukocyte- and platelet-rich fibrin) is one of the four families of platelet concentrates for surgical use and is widely used in oral and maxillofacial regenerative therapies. The first objective of this article was to evaluate the... more
    L-PRF (leukocyte- and platelet-rich fibrin) is one of the four families of platelet concentrates for surgical use and is widely used in oral and maxillofacial regenerative therapies. The first objective of this article was to evaluate the mechanical vibrations appearing during centrifugation in four models of commercially available table-top centrifuges used to produce L-PRF and the impact of the centrifuge characteristics on the cell and fibrin architecture of a L-PRF clot and membrane. The second objective of this article was to evaluate how changing some parameters of the L-PRF protocol may influence its biological signature, independently from the characteristics of the centrifuge. In the first part, four different commercially available centrifuges were used to produce L-PRF, following the original L-PRF production method (glass-coated plastic tubes, 400 g force, 12 minutes). The tested systems were the original L-PRF centrifuge (Intra-Spin, Intra-Lock, the only CE and FDA clea...
    The scope of this working group was to review (1) ecological interactions at the dental biofilm in health and disease, (2) the role of microbial communities in the pathogenesis of periodontitis and caries, and (3) the innate host response... more
    The scope of this working group was to review (1) ecological interactions at the dental biofilm in health and disease, (2) the role of microbial communities in the pathogenesis of periodontitis and caries, and (3) the innate host response in caries and periodontal diseases. A health-associated biofilm includes genera such as Neisseria, Streptococcus, Actinomyces, Veillonella and Granulicatella. Microorganisms associated with both caries and periodontal diseases are metabolically highly specialized and organized as multispecies microbial biofilms. Progression of these diseases involves multiple microbial interactions driven by different stressors. In caries, the exposure of dental biofilms to dietary sugars and their fermentation to organic acids results in increasing proportions of acidogenic and aciduric species. In gingivitis, plaque accumulation at the gingival margin leads to inflammation and increasing proportions of proteolytic and often obligately anaerobic species. The natur...
    Dysbiosis in the periodontal microbiota is associated with the development of periodontal diseases. Little is known about the initiation of dysbiosis. It was hypothesized that some commensal bacteria suppress the outgrowth of pathobionts... more
    Dysbiosis in the periodontal microbiota is associated with the development of periodontal diseases. Little is known about the initiation of dysbiosis. It was hypothesized that some commensal bacteria suppress the outgrowth of pathobionts by H2O2 production. However, serum and blood components released due to inflammation can neutralize this suppressive effect, leading to the initiation of dysbiosis. Agar plate, dual-species and multi-species ecology experiments showed that H2O2 production by commensal bacteria decreases pathobiont growth and colonization. Peroxidase and blood components neutralize this inhibitory effect primarily by an exogenous peroxidase activity without stimulating growth and biofilm formation of pathobionts directly. In multi-species environments, neutralization of H2O2 resulted in 2 to 3 log increases in pathobionts, a hallmark for dysbiosis. Our data show that in oral biofilms, commensal species suppress the amounts of pathobionts by H2O2 production. Inflammat...
    To analyse the regenerative potential of Leucocyte- and Platelet Rich Fibrin (L-PRF) during periodontal surgery. An electronic and hand search were conducted in three databases. Only randomised clinical trials were selected and no... more
    To analyse the regenerative potential of Leucocyte- and Platelet Rich Fibrin (L-PRF) during periodontal surgery. An electronic and hand search were conducted in three databases. Only randomised clinical trials were selected and no follow-up limitation was applied. Pocket depth (PD), clinical attachment level (CAL), bone fill, keratinized tissue width (KTW), recession reduction, and root coverage (%) were considered as outcome. When possible, meta-analysis was performed. Twenty-four articles fulfilled the inclusion and exclusion criteria. Three subgroups were created: intrabony defects (IBDs), furcation defects, and periodontal plastic surgery. Meta-analysis was performed in all the subgroups. Significant PD reduction (1.1±0.5mm, p<0.001), CAL gain (1.2±0.6mm, p<0.001), and bone fill (1.7±0.7mm, p<0.001) were found when comparing L-PRF to open flap debridement (OFD) in IBDs. For furcation defects, significant PD reduction (1.9±1.5mm, p=0.01), CAL gain (1.3±0.4mm, p<0.001)...

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