Poster 863, Sprache: Englisch
Porphyromonas gingivalis (PG) plays a key role in periodontitis. From dental plaque, bacteria also enter the blood stream and contribute to the pathophysiology of cardiovascular diseases. PG directly activates human platelets by a variety of mechanisms involving outer membrane structures and stimulation of protease-activated receptors by gingipains. Here, we investigate molecular mechanisms of platelet activation by various PG isolates.
Methods: PG isolates from 12 patients with acute periodontitis were investigated for their ability to activate human platelets by light transmission aggregometry and expression of the platelet surface marker P-selektin. Intracellular signalling pathways involved in platelet activation were determined by Western blot technique. In 4 patients with recurrent colonization after antibiotic therapy, PG isolates before and after therapy were compared.
Results: PG isolates showed high variability in platelet activation ranging from 0 to 100% aggregation. Furthermore, the time period for onset of aggregation varied between 1 and 9 minutes indicating that PG isolates use different platelet activation mechanisms. Corresponding results were obtained for platelet P-selektin expression and activation of intracellular activatory platelet pathways (e.g. MAP kinases or protein kinase C): while the majority of isolates activated platelet immune receptor FcγIIR and protease-activated receptors, 4 isolates used alternative pathways. Furthermore, 3 isolates induced platelet aggregation despite the presence of potent platelet inhibitors such as acetyl salicylic acid or nitrates. PG isolates from patients with recurrent colonization showed similar characteristics before and after therapy suggesting clonal persistence or reinfection during the study.
Conclusions: Interaction of platelets with individual PG isolates underlies high variability with regard to the degree of platelet activation and platelet signalling pathways activated. Certain PG isolates even induce platelet activation despite the presence of strong therapeutic platelet inhibitors. This variability of PG isolates may have an important pathogenetic impact on aggravation of cardiovascular diseases in patients with periodontal disease.
Schlagwörter: Platelet activation, Prophyromonas gingivalis, molecular mechanisms, Periodontitis
Poster 864, Sprache: Englisch
Aim: To evaluate the distribution of gingival biotype based on transparency of the periodontal probe among a
Palestinian population and correlation with morphometric data related to maxillary central incisors and
surrounding soft tissues.
Material and Methods: Among the senior dental students at Al-Quds University, Palestine; fourty-four volunteers with healthy periodontium
and absence of any restorations or history of orthodontic treatment were evaluated. Clinical parameters related to
both maxillary central incisors included: Crown width/crown length ratio (CW/CL), gingival width (GW), probing
depth (PD), and gingival thickness (GT). A periodontal probe was inserted in the midbuccal sulcus of the incisor to
visually evaluate if it had a thin or thick gingival biotype.
Results: The study involved 32 females and 12 males; all their ages ranged between 22 and 24 years. Although clinical
parameters of CW/Cl, GW, and PD were all smaller in females (0.76, 5.75 mm, and 1.47 mm, respectively); none
of them were significantly different from males (0.80, 5.9 mm, and 1.64 mm, respectively). Three clusters where
determined: cluster A (eight females, four males) for clear thin-scalloped gingiva, cluster B (fifteen females, four
males) for cases where it was unclear to be neither thin-scalloped nor thick-flat, and cluster C (nine females, four
males) for clear thick-flat gingiva. Clinical parameters of CW/Cl, GW, and PD were all statistically significantly
different between clusters A and B.
Conclusion: Nearly one-third of the examined population had clear thin-scalloped gingiva with similar portion for thick-flat
gingiva. Positive correlation is present between thick-flat gingival and greater clinical parameters of CW/CL, GW,
Schlagwörter: gingiva, periodontal health, periodontal probe
Poster 865, Sprache: Englisch
Purpose: The aim of this split-mouth, double-blind, randomized study is to evaluate if pulsed electromagnetic fields treatment can improve swelling and pain management after a full-arch immediate loading implant surgery.
Materials and methods: Eleven patients were selected for the study. Each patient received four implants in the upper or lower jaw using distal tilted implants and underwent a full-arch immediate loading rehabilitation.
After surgery two pulsed electromagnetic fields (PEMF) devices were applied on the right and the left cheek of each patient. Randomly one PEMF device was switched on (test side), applying the other one as a placebo (control side).
48 hours after surgery clinicians estimated the postoperative swelling through photographic documentation, comparing the condition prior and after surgery, while pain was assessed using a verbal rating scale. Patient's comfort degree in relation to PEMF devices was analyzed by questionnaires using a numerical rating scale.
Results: No statistically significant difference was observed between the test side and the control one as regards to swelling and pain (p>0.05). Most of patients did not present swelling or pain 48 hours after surgery, without distinction between PEMF device activated and not. Variable outcomes emerged from comfort evaluation.
Conclusion: Within the limits of this study, PEMF does not reduce postoperative swelling and pain after immediate loading implant surgery.
Schlagwörter: immediate loading, implant surgery, pulsed electromagnetic field, PEMF, postoperative swelling, pain
Poster 866, Sprache: Englisch
Intoduction: External invasive root resorption (EIRR) is an insidious and often aggressively destructive form of external root resorption, that occurs when the protective precementum layer is mechanically damaged or removed which allows for the denuded areas of the root surface to be colonized by clastic cells and for the resorption to get progressively worse, which usually affects a single tooth. This type of resorption develops slowly and initially without symptoms and may occur as a late complication following dental trauma particularly where it involves damage to cementum and supporting tissues. While this resorption may be evident clinically as a pink coronal discolouration, later with enamel's cavitation, often there are no obvious external signs and the condition is occasional detected radiographically. It is characterised by the invasion of the cervical region of the root by fibrovascular tissue, which progressively resorbs dentine, enamel and cementum. The dental pulp remains protected by an intact layer of dentine and predentine until late in the process. Ectopic calcifications can be observed in advanced lesions both within the invading fibrous tissue and deposited directly onto the resorbed dentine surface. The aetiology of external invasive root resorption is unknown but trauma has been documented as a potential predisposing factor (mostly concussion), however orthodontic treatment, orthognathic and dentoalveolar surgery, periodontal therapy and tooth whitening procedure can also induce external invasive root resorption.
Objectives: As early diagnosis is difficult, the dentist should be aware of this pathology and severity of clinical signs that may suggest it's presence, to be self sufficient and capable of diagnosing the aforementioned dental pathology.
Methods and results: Male patient, 45 years, emerged at Dental Clinic of Faculty of Medicine, University of Coimbra, Portugal, with symptoms to percussion in tooth 15, right second premolar, restored with ceramic onlay held for nearly five years without leakage, no hemorrhage on probing or periodontal pocket and by conducting periapical ortorradial observed endodontic treatment accompanied by a radiolucent area in the demarcated middle third root structure by a thin radio-opaque line that matches the outlines of the canal area overlapping the irregular external invasive root resorption which may be associated with a slight irregularity in the adjacent bonecrest. On the first moment, endodontic treatment was performed; medication intracanalar was calcium hydroxide (Calcicur-Voco) and thermoplastic obturation (SystemB-Analytic Technology) was made aided with gutta percha and endodontic sealer based on epoxy resin (AHPlus-Dentsply). After 18 months, the patient appeared again with new pain symptoms, accompanied by edema and erythema of the buccal and palatal region of tooth 15. Endodontic surgery was performed with curettage of the lesion and lateral periodontal bone regeneration was made with natural bone substitute material (Bio-Oss-Geistlich).
Conclusion: Controls were affected after 12 and 30 months, at the time of controls and nowadays the tooth remains asymptomatic and functional.
Schlagwörter: external invasive root resorption, MTA, diagnosis, treatment
Poster 867, Sprache: Englisch
Introduction: There is a broad consensus among the studies that the presence of Apical Periodontitis (AP) at the time of endodontic treatment (ET) has a negative influence on prognosis, which is an important issue to consider.
Objectives: The aim of this investigation is to estimate the prevalence of ET, the prevalence of AP in the adult population and the index of decayed, missing and filled teeth (DMFT) attending to the Dental School of Faculty of Medicine on the University of Coimbra.
Methods: Panoramic radiographs of all 229 patiens attending the Dental School of the Coimbra Medical University during the period of 1st January to 31st December of 2011 and periapical x-ray were registered to root-filled teeth. Statistical analysis was performed by SPSS, version 18 and the statistical tests were evaluated with the significance level of 5%.
Results: The sample size was 229 patients, distribute by gender, 39.7% were men and 60.3% were women aged between 18 and 84years. The prevalence of ET in the sample was 31% and the prevalence of AP in the patient's was 28.9%. A total of 4610 teeth were examined, based on that the prevalence of AP was 3.3% and the prevalence of AP in endodontically treated teeth was 3.5%. However, when endodontic treated teeth were examined, the prevalence of AP was 39.8%. In rootfilled teeth the prevalence of AP was 53.4%. When investigated from the point of view of the DMFT index, differences on gender were not statistically significant and index showed an increase through life due to the cumulative effect of caries lesions.
Conclusion: The prevalence of AP in the patient's sample was similar to the previous studies reported in Europe, specifically Ireland and Norway. Furthermore, the results resembled to the study in Portugal at 1998.
Schlagwörter: cross-sectional study, apical periodontitis
Poster 868, Sprache: Englisch
Retreatment is an attempt to re-establish healthy periapical tissues after inefficient treatment or reinfection of an obturated canal because of coronal or apical leakage.
Aim: To compare the efficacy of R-Endo, Mtwo retreatment and Protaper D Files for the removal of gutta precha using cone beam computed tomography and stereomicroscope.
Methodology: 60 mandibular premolars were obturated using Calamus 3D Obturating system. Gutta percha was removed using the three rotary retreatment files. Amount of gutta percha left was evaluated using cone beam computed tomography and stereomicroscope.
Result: R Endo removed more gutta percha in the middle and apical third where as Mtwo files in the cervical third. Protaper D Removed the least amounf of gutta percha at all levels.
Conclusion: R Endo retreatment file proved to be the most efficient system then MTwo and Protaper D Files.
Schlagwörter: retreatment, calamus, two retreatment file, protaper, endo
Poster 869, Sprache: Deutsch, Englisch
Hintergrund: Morbus Crohn (MC) ist eine chronisch entzündliche Darmerkrankung, die häufig von parodontalen Symptomen begleitet wird. Aufgrund seiner Bedeutung im Rahmen der wirtsspezifischen Immunantwort wurde dem TNF-a und seinen genetischen Besonderheiten eine wichtige Bedeutung in der Pathogenese entzündlicher Erkrankungen beigemessen. Aus diesem Grund bestand das Ziel der vorliegenden Studie darin, die Bedeutung von TNF-a-Polymorphismen für parodontal entzündliche und orale mukokutane Veränderungen bei MC Patienten zu untersuchen.
Patienten und Methoden: Insgesamt wurden 142 MC Patienten in die Studie aufgenommen. Orale Gewebeveränderungen und parodontale Parameter (Plaqueindex, Sondierungsblutung, Sondierungstiefe, klinisches Attachmentlevel) wurden erfasst. Mittels PCR-SSP (CTS-PCR-SSP Tray Kit, Heidelberg, Germany) erfolgte die Bestimmung von TNF-a Genotypen, Allele und Haplotypen (rs1800629: c.-308G>A and rs361525: c.-238G>A).
Ergebnisse: MC Patienten, die häufiger orale mukosale Läsionen aufwiesen, waren signifikant häufiger A-Allelträger (rs361525) als weniger häufig betroffene MC Patienten (14.2% vs. 2.2%; p
Schlagwörter: TNF-a, Genetik, Morbus Crohn, Parodontitis
Poster 870, Sprache: Deutsch, Englisch
Einführung: Ein Zusammenhang zwischen der Inklination der Okklusionsebene und vertikalen dentalen und skelettalen Relation ist seit den Untersuchungen von Schudy (1963) bekannt. Verschiedene Therapiestrategien versuchen einen solchen Zusammenhang auch für sagittale Anomalien auszunutzen.
Fragestellung: Gibt es statistisch signifikante Zusammenhänge zwischen der Inklination der Okklusionsebene und sagittalen und vertikalen Parametern im Fernröntgenseitbild (FRS)?
Material und Methode: Es stand für die Untersuchung eine Stichprobe von 442 FRS (mittleres Alter 28,3 Jahre, SD 7,8 Jahre; 175 männlich; 267 weiblich) kieferorthopädisch unbehandelter Erwachsener zur Verfügung. Alle FRS wurden mit der Analyse nach Segner und Hasund, ergänzt um die Frankfurter Horizontale (FH), ODI, APDI, Overbite und Overjet, ausgewertet (insgesamt 14 abhängige Variablen). Die Inklination der Okklusionsebene wurde zur Unterkiefergrundebene (OP-MP) und zur Frankfurter Horizontalen (FH-OP) bestimmt. Mittels Korrelationsanalyse (Pearson) wurde nach linearen Abhängigkeiten der Variablen gesucht und mittels t-Test (gegebene Normalverteilung) auf Signifikanz geprüft.
Ergebnisse: Von den 14 untersuchten Variablen zeigten nur ArGoGn (r=0,643; p=0,000), ML-NSL (r=0,633; p=0,000), der Index (r=-0,541; p=0,000) und der ODI (r=-0,544; p=0,000) eine starke Korrelation zu OP-MP. Zu FH-OP wies nur ML-NSL (r=0,596; p=0,000) eine starke Korrelation auf. Werden auch schwächere Korrelationen (0,3
Schlagwörter: Okklusionsebene, Fernrölntgenseitbild, Regression
Poster 871, Sprache: Deutsch, Englisch
Zielsetzung: Ziel der Untersuchung war es, die zellulären Reaktionen auf unterschiedliche porkine Kollagenmembrane zu analysieren und daraus Anwendungsempfehlungen für den klinischen Einsatz abzuleiten.
Material und Methoden: In einer systematischen in vivo Analysereihe wurden fünf kollagenbasierte Membrane histologisch untersucht. Die Kollagenmembrane Gesitlich BioGide® (BG), Gesitlich Mucograft® (MG), BEGO Kollagen Membran® (BEG), Mucoderm® (MD) und Collprotect® (CP) wurden nach einem standardisierten Versuchsprotokoll bis zu 60 Tage subkutan in Mäuse/Ratten implantiert und anschließend, mit einem Schwerpunkt auf die Gewebsreaktion und die Ausprägung einer möglichen Entzündungsreaktion histologisch untersucht
Ergebnisse: Die histologische Untersuchung zeigte deutliche Unterschiede hinsichtlich der zellulären Reaktionen auf die verschiedenen Membrantypen. So induzierten BG und MG lediglich mononukleäre Zellen wie Makrophagen, welche das Fehlen einer Fremdkörperreaktion und somit eine hohe Materialintegration darstellen. Hingegen bestand die Reaktion auf BEG, MD und CP auch aus mehrkernigen Riesenzellen, die im Rahmen einer Fremdkörperreaktion aus Makrophagen entstehen und ins Implantationsbett migrieren. BG, MG und BEG zeigten eine vollständige Volumenstabilität und -integrität. Die aus zwei Schichten bestehende MG Matrix zeigte an der spongiösen Schicht gerichteten Zelleinwuchs, wohingegen die kompakte Lage als stabile Barriere erhalten blieb. MD zeigte durchgehenden Bindegewebseinwuchs entlang ihrer präformierten Leitstrukturen aus Fettzelllakunen und Gefäßlumina. Im eingedrungenen Bindegewebe konnten nutritive Gefäße detektiert werden. CP zeigte durchgehenden Bindegewebseinwuchs und eine Reduktion der Membrandicke auf 75 % der Ursprungsdicke.
Schlussfolgerung: Für den klinischen Einsatz kollagenbasierter Membrane ist eine genaue Kenntnis der zellulären Reaktionen im Augmentationsgebiet von essentieller Bedeutung. Sowohl die zelluläre Reaktion als auch die Volumenstabilität und die Membranpermeabilität haben entscheidenden Einfluss auf den klinischen Erfolg und wurden in der vorliegenden Untersuchung unter standardisierten Bedingungen bestimmt.
Klinische Relevanz: Kollagenbasierte Membrane dienen in der Parodontologie und Implantologie als vielfältig einsetzbare Barrieren, die bei der Regeneration konkurrierende Gewebearten abschirmen sollen. Sowohl die zelluläre Reaktion als auch die Volumenstabilität und die Membranpermeabilität haben, abhängig vom Indikationsgebiet der Kollagenmembrane, entscheidenden Einfluss auf den klinischen Erfolg.
Schlagwörter: Kollagenmembrane, GTR, GBR, Bio-Gide, Mucograft
Poster 872, Sprache: Englisch
Introduction: Removable partial dentures are moving during use in directions and with magnitudes depending on the Kennedy class of the edentulous situation and on the size, direction and point of application of masticatory forces transmitted to the denture. These movements can harm the soft and hard tissues and also the denture, especially in free-end saddle situations. The aim of this study is to examine the distribution of stresses on a mandibular removable partial denture with attachments under occlusal forces, using finite element method analysis.
Material and method: a class I Kennedy mandibular removable partial denture with extracoronary attachments was put in a CT scan and the images were used to achieve a 3-dimensional model in Autodesk Inventor software. First, the 3D model of half of the denture was developed and then the whole denture using the "mirror" technique was obtained. On this model, forces both in the long axis of the teeth and in bucco-lingual direction were applied. All materials were assumed to be homogeneous, isotropic and having linear elasticity.
Results and discussion: masticatory forces create displacements, tensions and specific deformation in the denture's structure. The study demonstrates the effect of sagittal tipping of the free-end saddle dentures under the occlusal load, compared to the ideal situation in which the dentures wouldn't suffer any displacement. The saddle deformation is higher in the extreme distal area where there is only acrylate compared to the mesial area where the saddle is metalo-acrylic. The greatest deformation has been reported on the matrix of attachment.
Conclusions: Through a proper design, the removable partial denture with attachments is able of dealing with almost all displacements trends.
Schlagwörter: removable partial dentures, 3D modeling, FEM analysis, stresses
Poster 873, Sprache: Englisch
Aim: The present case report describes the effect of plaque accumulation and occlusal overload on peri-implant bone loss and implant failure.
Methods: A 43-year-old male patient came for consultation because of crown loss on one implant (Winsix 3,8 x 11 mm) at the level of the left first molar in the mandible. The clinical and radiographic examination revealed severe peri-implant bone loss and gingival inflammation associated with poor oral hygiene. The patient had an Angle class type II and no history of clenching. Although the implant was considered failed, it was stable so the decision was taken not to remove it. The patient was followed-up for 2 years and bone level was evaluated over time. Periapical x-rays, plaque index (PI), bleeding on probing (BOP) and probing depth (PD) were recorded at baseline (T0), after 6 (T6) and 12 months (T12). After 12 months, the extractions of teeth 45, 46, 47 were performed due to destructive caries and a provisional screw-retained composite crown was realized on the implant (site 36) in order to improve mastication. During the 2-years follow-up, professional oral hygiene sessions were performed every 6 months and the patient received instructions for home dental care, but his compliance was very low. Six months after loading, the patient came at the Dental Department because of implant mobility, pain and suppuration at the implant level. The implant was removed.
Results: During the entire follow-up period, the patient presented a PI and BOP of 100% at the level of the implant site. Both at T0 and T12, mean PD and mean peri-implant bone level next to the implant were 7 mm and 6 mm respectively, and 8.6 mm and 7 mm at T18 respectively. At T24 suppuration, pain and implant mobility appeared.
Conclusion: In the present case report the dental implant remained stable as long as the implant was not loaded, although a 100% PI was present. In contrast, as soon as an occlusal load was applied peri-implant bone loss and implant failure occurred. Clinical trials based on a greater number of patients are needed to validate the present outcomes.
Schlagwörter: plaque, overload, implant failure
Poster 874, Sprache: Englisch
Aim: To assess children's behaviour during dental treatment using Entonox.
Method: A group of 86 children referred to the ICEDM due to uncooperativeness was recruited for study. Inclusion criteria: ASA (Physical Status Scale) score I, II, Frankl behaviour rating scale (FSB) score 2 during initial visit, no medical contraindications for Entonox administration, parental informed consent. The study sample characteristics: 46 boys (53.5%), 40 girls (46.5%) aged 3-12 yrs. FSB score was recorded during initial visit, dental treatment and follow-up visit (3 months later). The 4 grade scoring was used for assessing children's self-management of inhalation namely as easy, neutral, difficult and unacceptably difficult. The following variables were recorded: the patient's age and sex, new vs. established ones, fillings vs. extractions, Entonox-naive vs. Entonox-experienced ones, Entonox-naive vs. other conscious sedation experienced ones, absence/presence of amnesia after treatment. Chi-square test at the 5% level of significance was applied for calculation.
Results: 6-12 aged managed self-administration of Entonox easier (p=0.03) than 3-6 aged. Behavioural change between the initial visit and follow-up visit: better cooperativeness 35 (40.7%), no change 47 (54.7%), worse cooperativeness 3 (3.5%). Differences in behaviour score: 3-6 yr olds vs. 6-12 yr olds: p=0.01, boys vs. girls: p=0.10, new patients vs. established ones: p=0.37, Entonox -experienced patients vs. Entonox-naive ones: p=0.02, other conscious sedation experienced ones vs. Entonox-naive patients: p=0.33, restorative treatment vs. extractions: p=0.78, amnesia in children treatment-naive vs. treatment-experienced ones: p=0,003.
Conclusions: Entonox administration enhances children's cooperativeness during dental treatment and helps reduce dental fear during follow-up visits.
Acknoledgement: Supported by program PRVOUK-P 28/LF1/6.
Schlagwörter: behavioural management, conscious sedation, children dental anxiety, nitrous oxide
Poster 875, Sprache: Englisch
Traditionally oral cancer has always been associated with tobacco and areca nut chewing habit. An emerging concept is that tumor development and progression is also largely dependent on the cross - talk between immune system and tumor cells.
Amongst internal agents, tumor associated macrophages and fibroblasts, play a pivotal role. Cytokines released by fibroblasts crucially affect the carcinoma cell behaviour and the role of chronic inflammation in tumor progression has now widely accepted. Amongst external agents causing infections like, fungal agents(candidiasis) and viruses (HPV and EBV) , with oral cancer have already been discussed by many researchers. It is the bacterial population (H. pylori) in microenvironment, which is now continuously increasing the concern of the scientists towards itself.
H. pylori association has already been established with gastric, pancreatic and hepatocellular cancers. It is present in oral cavity with GCF and plaque as its ecological niche and is shown to release inflammatory mediators like cytokines, when associated with chronic gingivitis and periodontitis. These inflammatory mediators when accumulate in the microenvironment of tissues for prolonged periods of time have the capacity to induce cell proliferation and to promote prolonged cell survival through activation of oncogenes and inactivation of tumor suppressor genes. This results in genetic instability with increased risk of oral cancer.
Association of H. pylori is still a grey area of study as not many studies have been done in respect to the same. Hence, this study is done to outline the association between H. pylori, its role in chronic inflammation and finally the progression of the disease towards oral cancer.
Schlagwörter: oral cancer, tumor microenvironment
Poster 876, Sprache: Englisch
Objective: Frequency of activation during distraction can theoretically influence the process of distraction osteogenesis. The aim of the study is to evaluate the effect of two different frequencies of distraction in the amount and architecture of new bone using a tooth-borne distractor.
Materials and Methods: Ten beagle dogs, weighing between 15-18kg, were used. Three remained as the control group and seven underwent a mandibular distraction protocol. Both hemi-mandibles were used for experimental purposes, with the following division: Group A: Six did not undergo any surgical procedure, remaining as a control group; Group B: Seven were subjected to two daily activations of 0.5 mm, with an interval of twelve hours; Group C: Seven received a single daily distraction of 1mm. After the distraction period, all devices were properly blocked and submitted to a consolidation period of 12 weeks. The mean distraction achieved was 9,8 mm. The evaluation of bone tissue was made radiographically and by Dual X-ray absorptiometry, and the values obtained were subsequently sent for statistical analysis.
Results: Radiographic evaluation showed that a greater the consolidation period leads to a greater amount of bone tissue in the distraction gap. There were no statistically significant differences in bone mineral content and bone mineral density among groups A, B and C. There were statistically significant differences between the coefficient of variation in groups B and C (p=0,041).
Conclusions: An increased in rhythm from one to two daily activations changed the quality of new bone present in the area created by distraction.
Schlagwörter: Distraction osteogenesis; Mandible; DEXA scan