Poster 57, Sprache: Englisch
For a good functional and esthetic longterm result of implant therapy, often soft tissue augmentation procedures have to be performed. Connective tissue grafts and free gingival grafts are recommended as standard procedures to create a stable peri-implant surrounding. Disadvantages are the morbidity and the size limitation of the donor site area.
Alternatively a gingival biopsy can be harvested for tissue engineering of an autogenous keratinocyte graft. The in vitro cultured keratinocytes are placed on top of the wound site after peri-implant vestibuloplasty.
The clinical results show that transplantation of in vitro cultured autogenous keratinocytes are an additional alternative for soft-tissue augmentation and may replace soft tissue grafts in selectedindications.
Schlagwörter: tissue engineering, dental implants, soft tissue, oral rehabilitation
Poster 58, Sprache: Englisch
Five current dentin adhesives were evaluated for their ability to bond to caries affected dentin. The materials were a total etch (Solid Bond (SB)), two self etch (Clearfil SE Bond (CSE), Etch and Prime (EP)), two one bottle (Prime and Bond 2.1 (PB), One Coat Bond (OCB)). 60 extracted molar teeth with proximal caries (mesial or distal) extending into mid-dentin were used. By grinding normal and caries-affected proximal surfaces, flat dentin surfaces were obtained. The surfaces were then bonded with each adhesive systems and composite resins were added to the surfaces by packing the material into a cylindrical-shaped plastic matrix with an internal diameter of 2.5 mm and height of 3 mm. Shear bond testing was performed following 10 days incubation of specimens in distilled water at 37 °C. Results were analyzed by Kruskal-Wallis ANOVA, and Mann-Whitney U multiple comparison test and Wilcoxon Rank Tests.The results obtained with CSE, SB, and EP were similar in caries affected and normal dentin (p>0.05). But bonds made to normal dentin with OCB and PB were lover (p
Schlagwörter: Caries affected dentin, bond strength, dentin bonding agent
Poster 59, Sprache: Englisch
Installation of fixtures for prosthetic reconstruction in the upper jaw in patients with extensive bone and soft tissue defects is still a challenge. These situations normally require thesupport of vascularized bone or composit grafts and secondary insertion of endosseous implants.As an alternative zygomaticus fixtures can be used. The dimension of these implants and thecomplex anatomy due to previous surgical procedures demand specific treatment for a precise and safe insertion of the implants. On the base of an axial spiral CT data set the STN-4 navigation system was used for the insertion of zygomaticus fixtures after subtotal maxillectomy. Computer assisted insertion was successfully completed (n=7). The implants could be positioned precisely as preoperatively planned. The use of zygomatic fixtures after ablative tumor surgery with resection of the maxillary bone provides immediate prosthetic reconstruction without additional bone grafting. Computer assisted insertion of these implants improves preoperative planning by valid 3D visualization of the anatomic situs and virtually positioning of the fixture and faciliates clinical procedure by guiding the drill to the intended position.
Schlagwörter: computer assisted surgery, implantology, maxillofacial surgery
Poster 60, Sprache: Englisch
The aim of the present study was to compare computer-assisted linear measurements of interproximal intrabony defects on radiographs using two different methods with the gold standard of intrasurgical measurements. In 22 patients with untreated advanced periodontal disease, 33 standardized radiographs were taken presurgically. The horizontal and vertical angulation difference of the central beam from the orthoradial projection and radiographic magnification were calculated for each radiograph. At the time of surgery, for 34 interproximal intrabony defects, the distance from the cemento-enamel junction (CEJ) to the bottom of the bony defect (BD) was measured. The distance CEJ to BD was assessed on the radiographs by two examiners that were blinded for the clinical parameters each using a different computer-assisted system (TSK: method 1; EH: method 2). Both radiographic evaluation methods underestimated interproximal bone loss statistically significantly [method 1: 0.70 ± 2.31 mm (p=0.006); method 2: 1.41 ± 2.58 mm (p=0.003)]. The difference in underestimation of bone loss between method 1 and 2 (0.71 ± 2.31 mm) failed to reveal statistically significance (p>0.05). A multivariate analysis confirmed this observation and failed to show any influence of projection geometry on underestimation of bone loss. Both computer-assisted methods used to measure interproximal bone loss on radiographs in this study underestimated the amount of bone loss statistically significantly.
Schlagwörter: computer-assisted radiograhic analysis, intrabony defects, periodontal diagnosis, linear measurements
Poster 61, Sprache: Englisch
The aim of this study was to assess the reliability of linear meas-urements of interproximal bone loss on digitized radiographic images after the use of different filters. Immediately before surgery 50 radio-graphs of 50 teeth with inter-proximal intrabony defects of 50 patients were obtained. Intrasurgically the distances from the cementoenamel-junction (CEJ) to the alveolar crest (AC) and from the CEJ to the deepest extension of the bony defect (BD) were assessed. All radiographs were digitized. Using the FRIACOM-software, the linear distances CEJ-AC and CEJ-BD were measured at the defects on digitized but unchanged radiographic im-ages and after the use of 2 image processing modes (filters: "spreading", "structure") with 7x and 14x magnification by 2 examiners. Repeated measures MANOVA revealed reproducibility of the measurement of the distance CEJ-AC to be significantly influenced by examiner (p = 0.01), height of 2 wall component of the intra-bony defect (p
Poster 62, Sprache: Englisch
In 13 patients with advanced periodontitis 30 periodontal defects (8 intrabony, 21 class II, 1 class III furcation) were treated by conventional surgery (n = 5) or guided tissue regeneration (GTR) using expanded polytetrafluoroethylene (n = 14) or Polyglactin 910 barriers (n = 11). Presurgically (BL), 6, and 60 months postsurgically clinical parameters (GI, PlI, PD, CAL-V, CAL-H) and 24 standardized radiographs were obtained generating 48 pairs (24 BL/6 months; 24 BL/60 months). Using subtraction analysis, bony fill within the defects was assessed. Surgically at baseline and by sounding 60 months after surgery vertical (PBL-V) and horizontal (PBL-H) bone levels were measured. Statistically significant (P
Schlagwörter: Furcation defects, intrabony defects, periodontal surgery, digital subtraction analysis, intrasurgical measurements
Poster 63, Sprache: Englisch
The LAUP (laser assisted uvulopalatoplasty) is a modified UVPP with a shorter time required for surgery and carried out as outpatient treatment. Reduction in snoring and a therapeutic effect on OSA (obstructive sleep apnea) has been demonstrated. This retrospective study was intended to clarify which reduction in snoring can be achieved and which complications may appear when getting outpatient treatment and when under local anesthesia.
Poster 64, Sprache: Englisch
Histological analysis of hard tissue is hampered by the fact that embedding in methacrylate reduces the spectrum for staining and labelling using monoclonal antibodies. It was the aim of this study to develop a new technique of sample preparation and histological analysis using confocal laser scanning microscopy (CLSM).Bone samples from the medial cortex of proximal tibiae of 3 dogs were removed during implant surgery and fixed in 4% formaldehyde for histological analysis. The material was divided into 4 pieces of similar size, the formaldeyde was removed, subsequently the specimens were stained for 24 h using RH 414 or DiOC 6/7 (Molecular Probes), which have been used for membrane labelling. The stained bone samples were analyzed in the Leica TCS 4D confocal laser scanning microscope (CLSM). Then they were embedded in paraffin or in laromin C 268 (BASF, Ludwigshafen) and thinned by grinding (Donath, 1982) for parallel analysis using CLSM, light (LM) and fluorescence microscopy (FM).Bone cells with their typical morphology could easily be identified by LM and CLSM, but not by FM. Cellular elements were still visible even when the focal plane was adjusted 60 µm below the sample surface. Optical sections in x/z-direction revealed cells even 100 µm below the surface irrespective of the mode of sample preparation. The newly developed technique allows microscopic analysis of cellular elements on the surface and below the surface without decalcification of the bone sample.
Poster 65, Sprache: Englisch
Several studies have focused on the potential role of interleukin 1 (IL-1) in periodontitis and gingivitis. To determine the influence of a toothpaste on the concentration of IL-1b in experimental gingivitis, we performed a double blind longitudinal study using a sample with vitamin A on a test group and placebo on a control group. Twenty four young healthy volunteers participated and were randomly divided into 2 groups. The following clinical parameters were assessed: Quigley-Hein plaque index (PLI) and Saxer & Mühlemann gingival index (GI). Examinations were performed at days 18, -14, -7, -4 before baseline, and days 3, 7, 14 and 18. All oral hygiene procedures were ceased at baseline. GCF was collected from the mesiobucal site of the upper right canine using periopapers. After measuring the volume at the Periotron 8000, the samples were analyzed at our lab for the detection of IL-1b concentration by ELISA with a commercial kit (Cistron technology, USA). Our results showed a reduction in PLI and GI prior to baseline in the two groups (almost 0), both incrementing after baseline (PLI » from 0.1 to 3.0, GI » 0 to 2.0). IL-1b concentration increased from baseline to day 18 in both groups (mean: from 200 ng/ml to 510 ng/ml and from 120 ng/ml to 445 ng/ml). The local vitamin A application did not influence the inflammatory reaction. We conclude that the use of vitamin A in this form of application, doesn't markedly influence clinical signs of experimental gingivitis as measured in the concentration of IL-1b in GCF.
Schlagwörter: experimental gingivitis, vitamin a, placebo, interleukin-1b, gingival crevicular fluid, Periotron 8000
Poster 66, Sprache: Englisch
The role of elastase in connective tissue disintegration and collagen breakdown in periodontitis has been demonstrated. Not only the concentration of elastase, but its proteolytic activity seems to be more significant for gingival inflammation and periodontal destruction. Alone or in a complex witha-1-proteinase-inhibitor or a-2-macroglobulin this enzyme might cause the progression of the disease. The aim of this study was to show a possible detection of elastolytic activity even in healthy volunteers. Previous investigations of our laboratory (1997) found high elastolytic activities in GCF samples from patients with marginal periodontitis. We analysed the samples with a synthetic polipeptide substrateMeO-Succ-Ala-Ala-Pro-Val-7-amino-4-methylcoumarin, according to investigations of Castillo et al. (1978) and Turner et al. (1994). The elastolytic activity was measured in a micro plate reader (Fluostar®). Recovery rates were performed at 3200, 1600 and 200 µU/µl of elastolytic activity. According to our results the reliability of this method is above 90%.In order to assess a possible loss of activity during storage, pooled samples were tested at various temperatures and measured after 6, 12, 24, 48 and 72 hours. We observed that when the samples were kept at room temperature for two days, their activity decreased to 85%.Maximum excitation of the substrate was found at 390 nm and fluorogenic emission at 460 nm. Assay pH was adjusted to 8.1 and samples were incubated at 25 °C for 6, 12 and 18 hours.27 male, healthy volunteers were treated in a period of two weeks with professional tooth cleaning and oral hygiene instructions. To avoid effects of a possible gingival irritation GCF was collected from the teeth 13 and 25 one week after the last professional tooth cleaning. Therefore two Periopapers® were placed in mesio- and distobuccal site of the gingival sulcus. The GCF-volume was measured with a Periotron 8000®. The samples from one tooth were immediately pooled in a buffer and stored at -80 °C and then analysed in our laboratory.The volunteers received fully oral and special periodontal examination. Persons, with no response to hygiene instruction, and those who received medication, as well as smokers, volunteers with subgingival prostheodontic restaurations, signs of gingivitis, and marginal periodontitis were excluded.Our microassay explored elastase in the GCF of all volunteers. The median elastolytic activity was 452 µU/µl. In comparison with other workgroups this activity can be explained, because the buffers used in this test are able to liberate elastase from neutrophile granulocytes contained in the GCF-sample.
Schlagwörter: elastase, experimental gingivitis, fluorometric assay, Periotron 8000, gingival crevicular fluid
Poster 67, Sprache: Englisch
Different cytokine genotypes have been described in periodontal disease. The aim of the present study was to investigate the genetic association of interleukin-10 (IL-10) polymorphisms in patients with early onset- (EOP) and adult periodontitis (AP) and to investigate possible associations with clinical manifestations. Based on clinical parameters and radiographs, 23 patients with AP and 18 patients with EOP were included in the study. Additionally, 21 healthy subjects, who were age-matched, were included as a control group. Genomic DNA was isolated from whole blood samples and the IL-10 promoter positions -597 and -824 were amplified by polymerase chain reaction (PCR). Polymorphisms were detected by restriction-enzyme cleavage. No statistical significance in the allele frequencies between patients and controls could be demonstrated. The *A and *C alleles at the -597 position were associated with the *T and *C alleles at the -824 position, respectively. We conclude that the investigated polymorphisms are not associated with periodontal disease.
Schlagwörter: Interleukin - 10, Polymorphisms, Early Onset Periodontitis, Adult Periodontitis
Poster 68, Sprache: Deutsch
Methods: In 24 patients with advanced periodontitis 39 intrabony defects were treated by the guided tissue regeneration technique using expanded polytetrafluoroethylene (n = 6) or bioabsorbable barriers (n = 32). Clinical parameters were assessed and 39 triplets of standardized radiographs were taken before, 6, and 24 months after surgery. Using a computer-assisted analysis the depth, width, and angle of the bony defects were measured.Results: Statisti-cally significant vertical attachment gains (CAL-V: 3.16 ± 1.63 mm / 3.29 ± 1.64 mm; P = 3 mm) intrabony defects bony fill was more pronounced than in wide and shallow defects (P
Schlagwörter: Knochentaschen, GTR, Defektwinkel, Defektweite
Poster 69, Sprache: Deutsch
The purpose of this study was to characterize different Ti-surfaces using REM and spectroscopy (AES and EDX) and to compare the quantity of bacterial compositions on different titanium surfaces using quantitative SEM- in vivo studies for assessing the effects of material selection on bacterial cell responses. The cp titanium units were obtained from titanium grade 1 and 2 with smooth like transmucosal implant collar-surface topographies by using the Dentaurum -casting technique and the Procera -milling technique. Titanium specimens were positioned on to the teeth for monitoring the subgingival early bacterial adhesion at 6, 12 and 24 hours. The quantitativ assesment of diameters of bacterial layers was recorded by using the software system PC Images for Windows. Early bacterial adhesion on the intrasulcular Ti-surfaces showed a difference between the two Ti-samples (cp Ti grade 1 and 2). The count of particles and their diameters after all times of intraoral exposition measured were greater in the Cp-group than in the Re-group of specimens. The differences were statistically significant (Mann-Whitney-U-Test, p= 0,05).All titanium specimens showed either a continuous or a fragmented coating by colonizing bacteria. Surface analysis using Auger Electron Spectroscopy (AES) indicated that the oxide thickness and the subsurface composition of titanium influence subgingival early bacterial adhesion. The inhibitory CH2-groups covered the outer TiOx - layer and could not be identified on casted titanium surfaces.
Schlagwörter: Quantitative, REM-Untersuchung, Biofilmbildung, Titanoberflächen