Poster 630, Sprache: Englisch
Introduction: Augmentation procedures in preimplant surgery uses a standard method. Different methods for extraction and processing of autologous bone used. The acquisition of bone chips and the the harvesting of bone blocks. Bone blocks and chips are both brought to the place where they are needed for augmentation, wherein the bone block is fixed by means of osteosynthesis in the final position. For a successful osseointegration not only the safe seat of the bone is important, but also a corresponding conturation in which the graft must be securely fixed, which often represents a challenge to the clinician. This are exactly the reasons why the bone-preperation block was developed.
Material and Method: With more than 300 patients were anatomically shaped bone graft from different points, taken with different dimensions. In the preperation block, they were worked with rotating and oscillating process outside the mouth. After processing, the bone was to be augmented in the situs and the fixation with osteosynthesis.
Results: In all patients the secure fixation of the samples collected and to ensure extra-oral bone graft conturation under water cooling. None of the patients broke the bone or damaged by excessive pressure in texture. Late graft losses were not as well.
Discussion: Safe fixation is a must for the extra-oral work, under water cooling, to augmenting of autologous bone blocks. Even the use of bonescrapers clamped on bone is ensured due to the secure fixation. The preperation block is therefore a useful and necessary complement to the existing augmentation sets.
Poster 631, Sprache: Englisch
Oral diseases and the patient's history of dental treatments can compromise important jawbone characteristics. If possible, extractions should be avoided for all patients who already suffered extensive bone loss because of the reduced stability and retention of the future denture, especially the lower one. Magnets increase retention of partial or complete dentures and overdentures regardless of the path of insertion. Magnets are easy to use alone or together with any type of retainers. Patient A.S., female, 62 years-old, referred the dental office for a complete rehabilitation complaining of chewing inefficiency and inesthetic appearance. The patient has a pathological history of osteoporosis and diabetes. The only mandibular tooth excepted from extraction was the canine (3.3) because of its good implantation and stability. After the surgical phase and the root canal treatment of 3.3, a cap-type magnetic attachment (Magfit, Aichi Steel Corporation, Japan) was applied. The technical simplicity, the usefulness for geriatric and handicapped patients, the increased control of jaw function trough the maintained periodontal ligament and the physiological action of magnetic forces in the tooth axis are arguments for the use of magnets.
Schlagwörter: magnet, retention, lower denture
Poster 632, Sprache: Englisch
Human mandibular canines do not present an internal anatomy as simple as could be expected; there are canines with a single root and two canals, two roots or fused roots. The existence of mandibular canines with more than one root canal is a fact that clinicians ought to keep in mind, in order to avoid failure during endodontic treatment. In spite of the low incidence of canines with one root and two canals or two roots, this possibility cannot be forgotten. These morphological variations raise difficulties in endodontic treatment.This article presents two clinical cases of mandibular canines with two canals in the same root and with two roots and two canals. In both cases the canines were used as abutments for a prosthetic restoration and both went undetected on the usual X-rays examination. In the first case the second canal was found during the endodontic treatment steps and its presence was confirmed with a second X-ray from another incidence. The second case is a retreatment followed by a surgical phase. The precise knowledge of the endocanalicular system's anatomy is essential for the success of the root canal therapy. The failure to detect all the canals and the incomplete canal filling ultimately results in the loss of the tooth. The long term success of the prosthodontic treatment depends directly on the quality of the endodontic treatment of the abutments. The mandibular canine is very important for any type of prosthetic restoration. The clinical cases reported show that such anatomical variations can also occur in Romanian population as much as described in the international literature and cannot be overlooked in private practice.
Schlagwörter: anatomical variation, mandibular canine, endodontic treatment
Poster 633, Sprache: Englisch
Objectives: The aim of the present study was to determine the effect of four different desensitizing agents (Gluma Desensitizer, Admira Protect, Hyposen, VivaSens) on root surfaces de- and remineralization in vitro.
Methods: The root surfaces of 90 freshly extracted caries-free human molars were thoroughly cleaned, thereby removing the cementum. The teeth were then coated with acid-resistant nail varnish, exposing a rectangular windows. All specimens were demineralized (De) for 14 days with acidified gel (HEC, pH 4.8, 37 degrees C). Before remineralization (Re) using a NaF-containing calcium-phosphate buffer solution one window was covered. Beside an untreated control group, the specimens were distributed among two main groups: In one group the desensitizer was applied before demineralization, in the other subgroup the desensitizer was applied after demineralization. From each tooth, two dentinal slabs were cut. The depth of the demineralized areas was determined using a polarized light microscope.
Results: The comparison between de- and remineralized groups showed a significant reduction of lesion depth in all cases (p
Schlagwörter: Dentin, Desensitizer, Demineralisation, Remineralisation, Dentin hypersensitivity
Poster 634, Sprache: Englisch
Introduction: Aesthetics has become a common demand in dentistry. As practitioners, we have to understand harmony, beauty, proportion, and symmetry when planning treatment. In Digital Era the analysis of patient's smile and the treatment plan could be done in digital mode.
Method: The Aesthetic Smile Criteria and usual software as Microsoft Power Point® were used for developing a method that simplifies the Smile Correction Protocol. As an example, we choose a simple clinical case of a lateral upper incisor situated in wrong position. The result leads us to the correct treatment plan.
Discussions: Due to this digital technique we can detect in an accurate way the needful changes of patient's smile and we are able to provide clinical precise information, useful for the dental technician in order to produce the ideal restoration.
Conclusions: The use of computer in Smile Design process permits us to achieve better results and to avoid any misunderstanding that can occur during the communication process with the dental laboratory.
Schlagwörter: smile design, perfect smile, software, aesthetic, digital mock-up
Poster 635, Sprache: Englisch
An alternative in the use of Co-Cr alloys is the laser sintering technique. The objective of this study is to assess the quality of Co-Cr prosthetic restorations, obtained with this method. Selective laser sintering technique uses a high power CO2 laser to fuse small particles of metal powders into a mass representing a desired 3-dimensional object. The laser selectively fuses metal powders by scanning cross-sections generated from a 3-D digital description by CAD file or scans data on the surface of a powder bed. After each cross-section is scanned, the powder bed is lowered by one layer thickness, a new layer of material is applied on top, and the process is repeated until the part is completed. The topography of the dental restoration is designed by numerical monitoring after having scanned devised prostheses. The laser is thus programmed in such a way that it only becomes active at the site where the element should be achieved. In our application the alloy consists of 64-67% Co, 28-30% Cr and 5-6% Mo, and has at equilibrium of a γ monophasic structure. Evaluation and characterisation was made by: Microstructure analysis; Corrosion resistance evaluation; Polarization test; Crevice corrosion test; Release of cations. Dimensional observations of Co-Cr restorations show that adjustment leads to satisfactory clinical results with a precision of 25 µm. The average hardness is 395HV, comparable to metallo-ceramic elements obtained by casting technique. The metallographic observations show a slight porosity in the horizontal plan (sintering plane). Punctual analysis shows a high regularity of the local chemical composition: 62.6-64%Co, 29.3-30.5%Cr and 4.9-6.4%Mo. Potentiodynamic polarization curves confirm the presence of the porosity in the structure of the restoration. SEM micrograph of the corroded surface after the polarization test shows: O 24.53, Na 1.19, Si 1.12, Cl 0.59, Cr 28.76, Co 34.30, Mo 9.52. The technique of manufacturing by selective laser sintering allows obtaining prosthetic elements of high dimensional precision which present mechanical properties in agreement with the clinical requirements. However, the residual porosity inherent to the sintering process may present a risk for fracture and crevice corrosion.
Schlagwörter: laser sintering, Co-Cr alloys
Poster 636, Sprache: Englisch
Overlays are representative of incisal edges of the teeth produced over transparent sheet. They are used most commonly for comparison of bite mark pattern of a suspect with that found on an animate or inanimate object. There are many techniques of overlay generation like the manual, photocopying and computer assisted techniques. With this background a study was conducted to evaluate various overlay generation techniques and to evaluate the inter-operator reliability in comparing the overlays generated. Overlay production was done by manual, photocopying and computer assisted techniques. As two examiners conducted the observation in our study, we were able to find the inter-operator reliability of the overlays generated. The computer assisted overlays were found to give reliable results.
Schlagwörter: Inter-operator reliability, manual, photocopying, computer assisted technique, Photoshop software version 7, magical wand selection tool
Poster 637, Sprache: Englisch
Reliable cementation of fixed prosthetic restorations represents one of the most sensitive and crucial tasks during the prosthetic dental treatment with desirable long term clinical success. Because of its particular structure, zirconia restorations require a special conditioning before cementation in order to achieve a strong bond to dental structure. The lack of information about adhesive cementation technique of zirconia based ceramics could lead to undesired failure. Our aim is to acquaint practitioners with particular structure of zirconium oxide and microscopic interaction with resin cement in adhesive cementation. We have studied the indication for use of eight out of the most used Zirconia brands in Romania. The results show that every manufacturer indicates to sandblast the inner surface of zirconia copings prior to adhesive cementation. The cementation itself could be done in two ways: usage of phosphate-monomer based luting agent or silicatisation of the zirconia surface followed by a regular adhesive cementation.
Schlagwörter: zirconia, adhesive cementation, MDP monomer, silicatisation
Poster 638, Sprache: Englisch
Objective: The present study was undertaken to evaluate the effect of alternative hemostatic agents used for pulpotomy such as ferric sulfate and 5% NaOCl on microtensile bond strength (mTBS) of two adhesive systems to pulpal floor dentin of primary teeth in vitro.
Methods: Seventy-two extracted primary molars were included. Dentin specimens of the pulp chamber were obtained under standardized conditions. The specimens were randomly assigned to one of the six groups of twelve samples each: group PB-C: Prime&Bond, control group; PB-1: immersion for five minutes in ferric sulfate prior to bonding with Futurabond, PB-2: immersion for five minutes in 5% NaOCl prior to bonding; groups F-C, F-1 and F-2 followed the same procedure with Futurabond NR as adhesive. MTBS was measured 15 minutes after application of the corresponding compomer (Dyract/ Glasiosite) using an universal testing machine.
Results: Statistical analysis showed a significant influence of the used dentin adhesive and the hemostatic agent (p< 0.001, ANOVA). The immersion in 5% NaOCl before bonding procedure (PB-2, F-2) resulted in a significant reduction of mTBS compared to the untreated control groups (PB-C, F-C) (p< 0.05, Tukey's test). Between the controls and ferric sulphate groups, significant differences could only be detected in the case of Futurabond NR (p< 0.05, Tukey's test). Pairwise comparison between Prime&Bond and Futurabond showed no significant differences in all groups (p< 0.05, Tukey's test).
Conclusions: Within the limitations of an in vitro investigation it can be concluded that hemostatic agents used for pulpotomy might have an adverse effect on mTBS of adhesive systems. In the case the self-etch adhesive Futurabond NR both hemostatic agents reduced mTBS.
Schlagwörter: pulpotomy, hemostatic age, dentin adhesives, microtensile bond strength
Poster 639, Sprache: Englisch
Introduction: First permanent molar is recognized as the most important tooth in the arch and its early loss generates morphological and functional disorders. Being considered a temporary tooth, parents overlook the early decay and children get to the dentist with advanced lesions. Cultural and educational models provided by parents have a decisive significance in shaping the child's proper oral health behavior. The aim of the study is to describe parents' views on first permanent molar.
Methods: A cross-sectional study was conducted in 4 randomly selected kindergartens. A self-administered 10 items questionnaire was distributed among 240 parents of preschool children attending these kindergartens in October 2010. The questionnaire covered parental knowledge towards the first permanent molar of their young children and demographic information. The ethical approval was obtained from the Ethical Committee of the University of Medicine and Pharmacy "Carol Davila", Bucharest.
Results: 210 parents returned the questionnaires and the rate of responsiveness was 87.5%. Most respondents were aged between 26-35 years (76%) and were females (88%). The majority (63.3%) had education higher than secondary school level. In terms of knowledge about the erupting age, half answered correctly, 26.6% responded that appears at 11-12 years and 23.3% say they do not know. Only 50% of parents knew that appears behind the temporary molars, without replacing another tooth. Regarding methods of preventing caries, one third of parents choose brushing teeth twice a day, 20.81% regular dental check-ups and 11.67% sealing teeth. The sources of information are: the dentist (36.7%), media (20%), the pediatrician (3%) and educators (2%).
Conclusions: The relatively low level of parental knowledge and low awareness of preventive methods indicated a need for them to receive accurate information about factors influencing the oral health of preschool children in Bucharest, Romania.
Schlagwörter: parents, education, preschool children, preventive treatment