Poster 514, Sprache: Englisch
Objectives: Aim of the present study was to evaluate the effect of saliva contamination and in vitro demineralisation on microtensile bond strengths (mTBS) of one self-etching (Delton) and two multi-step fissure sealants (Fissurit F, Smartseal) to enamel.
Methods: 135 freshly extracted molars stored in saline were included. The molars were sectioned at the cement-enamel junction and the roots were discarded. The crowns were sectioned in the mesio-distal direction, and flattened until a flat enamel surface area was reached. All specimens were randomly assigned to nine experimental groups of 15 samples each: Fissurit (FC, FS, FD), Smartseal (SC, SS, SD), Delton (DC, DS, DD). In groups FS, SS, DS saliva was placed on the enamel before the sealant was applied. In groups FD, SD, DD the enamel surface was demineralised using acidified gel technique (HEC, pH 4.8, 37°C) for 14 days before fissure sealant application. Groups FC, SC, DC served as controls. In these groups the enamel was sound. All sealants were applied as recommended by the manufacturer. MTBS was measured 15 minutes after application of the fissure sealant using an universal testing machine.
Results: Statistical analysis showed a significant influence of the used sealant and the contamination on mTBS (p < 0.001, ANOVA). Saliva contamination and demineralisation decreased mTBS. In case of Fissurit and Smartseal this increase was significant (p < 0.05, Tukey's test).
Conclusions: All fissure sealants used in this study were able to establish mTBS on enamel. Saliva contamination and in vitro demineralisation showed a significant impact on mTBS.
Schlagwörter: Cobalt-Chromium dental alloys, precious metals
Poster 515, Sprache: Englisch
Purpose: Implants have been incorporated into removable partial dentures to provide support and retention. The placement of two distal implants has been recommended to transform Kennedy class I to a Kennedy class III situation. The term implant-assisted was employed to describe the use of attachments to improve retention. The aim of this study is to assess the stress and strain behaviour of two different matrix design of ball attachment incorporated into an existing removable partial denture using a 3dimensional finite element analysis (FEA).
Material and methods: Two models of partially edentulous mandible (Kennedy class I) were constructed using FEA software. The implant model simulated a commercially available model with a diameter of 4.8 mm and a length of 12 mm. The models were loaded with a vertical force of 120 N. FEA software was used to analyze the stress and strain patterns.
Results: Maximum stress/strain values were located around the implants in both models. The ball attachment with titanium matrix system showed higher stress/strain values compared with the elliptical matrix ball attachment.
Conclusion: Within the limits of this study, the use of elliptical matrix ball attachment system showed a more favourable stress/strain distribution over the use of the titanium matrix ball attachment system with implant assisted removable partial denture (IARPD).
Schlagwörter: attachment, implant, removable partial denture
Poster 516, Sprache: Englisch
Objectives: The aim of this study was to evaluate the effect of a recently introduced desensitizing paste based on Pro-Argin technology (GABA GmbH, Germany) on microtensile bond strength of a resin cement system (Futurabond DC, Bifix QM) after artificial aging using water storage and application of provisional cement (Provicol QM).
Methods: 60 freshly extracted third molars were included. All teeth were specially prepared allowing the simulation of dentin perfusion and standardized conditions. The specimens were randomly assigned to four experimental groups of fifteen each: group 1: control without desensitizer; group 2: desensitizing paste application; group 3: desensitizing paste, water storage; group 4: desensitizing paste, application of Provicol QM, water storage. Group 3 and 4 were stored in water for one week. In group 3 Provicol QM was additionally applied after desensitizer application. Microtensile bond strength was measured using an universal testing machine.
Results: For the test series following tensile bond strengths were evaluated (mean values and standard deviations in MPa): Group 1: 14.04 (±2.64), group 2: 12.20 (±1.94), group 3: 12.68 (± 1.72), group 4: 10.61 (± 1.85). Statistical analysis showed a significant influence of the different aging procedures on microtensile bond strength (p < 0.001, ANOVA). After application of the desensitizing paste no significant reduction of bond strength could be observed compared with the untreated control. Pairwise comparison showed no significant reduction of bond strength in specimen after water storage. Compared to the untreated control, the additional application of the provisional cement bond strength reduced bond strength significantly (p < 0.05, Tukey's test).
Conclusions: Within the limitations of an in vitro investigation it can be concluded that application of the desensitizing paste based on Pro-Argin technology might not affect microtensile bond strength of the used self-etch adhesive system. However, the additional use of provisional cement decreased bond strength significantly.
Schlagwörter: dentin, dentin hypersensitivity, bond strength, desensitizier, artificial aging
Poster 517, Sprache: Deutsch
Objective: Aim of the study was to investigate differences between the wound healing patterns of provisionally restored immediate implants in comparison to delayed implants at 2nd stage surgery on a molecular immunological basis.
Patients and Methods: In 36 implants (Replace, Nobel Biocare) of 21 individuals (10 men and 11 women; mean age 53, range 33 - 84 years) the gingival crevicular fluid (GCF) flow rate, and sulcular concentrations of neutrophil elastase (NPE) and interleukin-1 beta (IL-1 beta) were assessed at four time points. Nine implants hade been placed according to a delayed placement protocol and were supplied with titanium healing abutments on re-opening two days before the onset of the study. The remaining 26 implants were placed as immediate implants directly following tooth extraction, and were restored with provisional acrylic single crowns the same day. In the immediate implants group the first samples were taken prior to tooth extraction. Three follow-up visits were scheduled over the first four weeks after surgery in both groups.
Results: IL-1 beta showed statistically significant lower concentrations in the immediate implants group as compared to the control group of delayed implants over the entire follow-up period. The levels for GCF flow rate and NPE were also notably lower than in the control group, but not on a statistically significant level.
Conclusions: The results of this preliminary pilot investigation point at different wound healing characteristics between immediately and delayed implants for the findings investigated. Immediate implants with immediate acrylic provisional restorations seem to exhibit a less pronounced peri-implant inflammatory reaction than delayed implants restored at second stage surgery with titanium healing abutments.
Schlagwörter: Sofortimplantat, Spätimplantat, Wundheilung, Interleukin-1, neutrophile Elastase
Poster 518, Sprache: Englisch
Turner syndrome is a chromosomal disorder in which one of the sex chromosomes is missing or has other abnormalities. It is usually associated with short stature, gonadal dysfunction, hypotiroidism, congenital heart disease. Distinct craniofacial features in Turner syndrome include micrognatia, high arch palate and malocclusion. In this poster is presented a case of a 30 years old female patient with Turner syndrome who presented a class III malocclusion with periodontically involved teeth, and multiple carious lesions. After the initial parodontal therapy and carious lesions treatment, we decide for the orthodontic treatment. After completing the orthodontic treatment, the patient presented a class III Kennedy partially edentulous maxilla with modification 1 and a class III Kennedy partially edentulous mandible and referred for the prosthodontic treatment. The treatment plan consist in two porcelain fused to metal fixed partial dentures and restoring the incisal edges to complete the smile design improvement. Despite the physical and psychological differences and other problems that can occur in Turner syndrome, with appropriate medical care, interdisciplinary collaboration and ongoing support, a person with Turner syndrome can lead a normal and healthy life.
Schlagwörter: Turner syndrome, orthodontic treatment, prosthetic rehabilitation
Poster 519, Sprache: Deutsch
Objective: The aim of the study was to investigate the bacterial contamination of different prosthetic components with periodonto-pathogens in healthy edentulous patients wearing long-standing implant-supported overdentures.
Patients and Methods: Bacteria samples were harvested from the peri-implant sulcus, the inside of the implant, and the soft tissue side of the denture base in nine patients from the Tuebingen Implant Registry on occasion of their annual hygiene and check-up visit. Samples were assessed by PCR (Hain MicroIdent Test). Five patients could be re-evaluated four weeks after the professional implant maintenance procedures.
Results: Orange complex representatives species dominated at all three locations, others were found only sporadically. P. intermedia and F. nucleatum were the predominant species at the denture base (p = 0.02). F. nucleatum alone and in conjunction with P. intermedia showed a statistically significant upward shift on the follow-up appointment (p = 0.03 for F. nucleatum and p = 0.02 for both). This effect was accompanied by a decrease in red complex species means, but not on a statistically significant level.
Conclusions: The presence of periodonto-pathogenic bacteria in healthy individuals should be recognized. The present investigation supports the idea that with a decrease in counts of the red complex species the number of bacteria in the orange complex increases, indicating a shift in plaque composition towards a slightly more favorable flora following professional maintenance procedures.
Schlagwörter: parodontopathogene Keime, Kontamination, Deckprothese, professionelle Mundhygiene, Follow-up
Poster 520, Sprache: Englisch
In the field of oral pathology odontogenic tumors have been a topic of considerable interest for researchers, academicians and many budding inquisitive minds like ours. The earliest reports on odontogenic tumors date back to 1839 and in spite of researches over the decades the etiology and pathogenesis of this distinct group of jaw lesions is still incompletely understood. It is well established that odontogenic tumors arise from the epithelial and/or mesenchymal elements of the tooth forming apparatus. And along with epithelial-mesenchymal interactions there are molecular and genetic alterations associated with the development and progression of odontogenic tumors. Recently it has been proposed that various tumerogenic factors (initiators) like oncogenes, tumor suppressor genes, hard tissue related proteins and growth factors and tumor promoting factors (supporters) like MMP, TIMP, cell adhesion molecules, angiogenic factors and osteolytic factors, all play a role in synchrony towards the genesis of odontogenic tumors. We intend to outline the multi-step etiology and draw the future attention towards better understanding of odontogenic tumors.
Schlagwörter: odontogenic tumors, tumor initiators, tumor supporters
Poster 521, Sprache: Englisch
Removable partial dentures are aesthetic alternatives for edentulous patients with good retention and stability.
Materials and methods. In this study the evaluated attachments were extra - coronal attachments, retentive ball attachments, telescopic crowns - retained removable partial dentures, bar clip attachments and magnetic retention. The number of the attachments was 217 and the surveying period was 3 years. The oral surveys were carried out by calibrated dentists in the Department of Prosthodontics, Timișoara, România in 2006-2009. The evaluation included the type of the partially edentulous arches, the type and the number of the attachments and the patients satisfaction regarding aesthetics, retention and stability during mastication and speech. Statistical analysis was performed for these evaluations. Each patient has signed and Informed Consent.
Results. The most frequently used attachments were the extra-coronal attachments (58,6%), followed by the ball attachments (24,4%), the telescopic crowns (11,05%), the bar clip attachments (4,6%) and finally the magnets (0,18%). The evaluated attachments have advantages and disadvantages in different clinical situation.
Conclusions. The mostly used attachments in this study were the extra-coronal attachments because these are easy to use and they fit well to the clinical situation. All the attachments used in this study were well accepted by the patients due to their good aesthetic and retention. Many of the patients included in the study mentioned that the galvanic telescopic crowns are too expensive for them. Also, using magnets involves a delicate technology, that is why our technicians are reserved in using these attachments.
Schlagwörter: removable partial dentures, extra-coronal attachments, ball attachments, telescopic crowns, bar clip attachments, magnets
Poster 522, Sprache: Englisch
Introduction: Albumin is known to play an important role for transportation of various proteins, peptides and low molecular weight molecules produced by tumor cells. The novel technique of spin labelling followed by electron spin resonance spectroscopy (ESR) is a tool to evaluate the structural and functional changes that can occur to albumin following the binding of various ligands. A difference of albumin functionality between cancer patients and healthy persons has been described in other tumor entities. Therefore, the present study investigated the value of ESR analysis for albumin-bound molecules as a possible biomarker in oral squamous cell carcinoma (OSCC).
Material and Method: ESR was tested blinded to the clinical data. Peripheral blood was isolated from 32 patients with histological verified OSCC (m=18, w=14; T1 n=11, T2 n=10, T3 n=6, T4 n=5; N0 n=24, N1 n=6) and tested against 30 healthy volunteers (age and gender matched). A discriminant variable (DR) was calculated. Obtained data were associated with pathological and clinical data.
Results: The analysis revealed a diagnostic sensitivity in detection of OSCC of 72% (23/32 patients with OSCC) and a specificity of 80% (24/30 healthy volunteers). A sub-group analysis with patients without leucocyte elevation (52 patients (84%; OSCC-group n=23, healthy volunteers n=29) was conducted. Here, sensitivity added up to 87% (20/23), specificity to 83% (24/29). In both groups, DR was significant different (p < 0.001) between OSCC- and volunteer group. ESR measurement "detected" all T4- as well as all N-1 stadiums.
Discussion: High sensitivity and specificity implies a promising approach towards detection of OSCC by peripheral blood analysis. Nevertheless, inflammation seems to be a major confounder. As OSCC is often accompanied with inflammation, the method may be not appropriate in these cases. Prospective studies with higher patient numbers and an optional combination with other biomarkers are needed to confirm the value of ESR in OSCC diagnosis.
Schlagwörter: oral cancer, diagnosis, electron spin resonance, albumin
Poster 523, Sprache: Englisch
Objectives: The aim of this study was to evaluate the mikroleakage of four fissure sealants in relationship to fissure configuration after articfical aging.
Methods: 843 fissures of extracted non-carious molars sealed with either Ultraseal XT, Conseal f, Smartseal or Delton were examined. Following prophylaxis with Klint, the fissure sealant was applied as recommended by the manufacturer. One half of the teeth was thermocycled (5-55 degree celsius, 5000 cycles). Following that, all teeth were immersed in methylene blue for 48 hours, rinsed, sectioned and examined with digital light microscopy (10-200x). Fissures were characterized as U, V, I and IK based on their cross-sectional shape. Microleakage was scored as 0= no dye penetration; 1= dye penetration into the occlusal third of the enamel-sealant interface; 2= dye penetration into the middle third of the interface; and 3= dye penetration into the apical third of the interface.
Results: Following mikroleakage scores were evaluated. Regardless of the fissure configuration, significantly higher average microleakage scores were obtained after thermocycling (p < 0.001, ANOVA). In particular, Smartseal yielded the highest microleakage scores after artifical aging (p < 0.05, Tukeys test).
Conclusions: Within the limitations of the present study, it can be concluded that artifical aging increased microleakage of the four fissure sealants significantly.
Schlagwörter: microleakage, fissure sealants, artificial aging, fissure configuration
Poster 524, Sprache: Deutsch
A mentally retarded patient with reduced physical abilities received five dental implants in different lengths and diameters. These implants were inserted under general anaesthesia supported via the Biomet 3i Encode Complete System. Due to the fact, the prosthetic reconstruction was implemented only months ago, there a no long-term follow ups until today. Thitherto the patient seems to be happy with her new prosthesis. This case report shall be an indication enhancement for implant-supported prosthetics in risk factor patients.
Schlagwörter: Implantate, Biomet 3i Encode, Risikopatienten, Risikofaktore
Poster 525, Sprache: Deutsch
This prospective study summarizes the clinical outcome in 60 cases of augmentative procedures with special regard towards amount of swelling, pain and possible inflammatory effects or complicationsas well as handling and histological features in 2-stage procedures when possible. The low expression of resorbtive cell reactions and de novo bone formation up to the former membrane level show the excellent tissue integration. There were no membrane associated complications. The stability of the bone substitute war perserved intil intergration was complete even in difficult cases. In those 5 cases with dehiscences and partial or complete loss of augmentation material the cause was either the dimension of the defekt or the muscular activity in the augmented area.
Schlagwörter: Augmentationen, Sinusbodenelevation, bone substitutes, Knochenaufbaumaterial, Implantate
Poster 526, Sprache: Englisch
The use of dental implants to replace lost anterior teeth has become a well established treatment option. Tooth loss due to endodontic or periodontic reasons often result in an inadequate alveolar bone volume and soft tissue situation for later implant placement. To achieve a functionally and aesthetically satisfying result in most cases hard and soft tissue augmentation is necessary. Mandibular block onlay grafts and connective tissue grafts are predictable methods to restore the alveolar ridge prior to implant placement and the gingiva around the implant prior to the final prosthetic restoration. An adequate provisional restoration additionally contributes to the success. This clinical report shows the successful replacement of a maxillary central incisor by an implant-supported single tooth restoration in a multistage procedure.