Papers by Keyword: Dental Implant

Abstract: The dental restorations by the usage of implants have been one of the most favourable treatment. However, the existing dense dental implant causes overloading towards the human bone that triggers ‘stress shielding effect’ and also implant loosening. This paper focused on the development of highly porous Ti-6Al-4V dental implant by metal injection molding with palm stearin binder system with an addition of sodium chloride as space holder which has been established in the fabrication of porous Ti-6Al-4V. The evaluated compositions consist of the powder volume fraction of 63vol% and 65vol%. SEM analysis shows that highly porous Ti-6Al-4V dental implant were obtained. The average density is 3.325g/cm³ for 63vol% sample and 3.915g/cm³ for 65vol% sample. While for the Vickers hardness are 113.68HV and 162.8HV for 63vol% and 65vol% respectively.

Abstract: In this paper, the purpose is to compare three different cone fit of dental implant around the surrounding bone tissue that influence on fatigue and biomechanics, it is also to provide a theoretical basis for the design and clinical application of dental implant. The method is that loading the force 100N and 200N with different angle to the three different cone with dental implant with the finite element analysis (FEA) that analyzes the stress and fatigue in ideal conditions. The Results is that when the loading is vertical, cone for 3 degrees of the implant have the best performance. The cone for 80 degrees of the implant is min among the max equivalent stress of the implants. However, comprehensive view, Cone for 24 degrees of the implant the most stable. we find that cone of different implant when subjected to the same force the maximum equivalent stress is different, smaller conical implant under vertical load force have good performance, but with the increase of the loading angle the bigger conical implant performance better.

Abstract: This study aimed to evaluate the biomechanical responses in the peri-implant bony structure installed with the fixed partial dentures (FPDs). Unlike traditional configuration, the FPD considered here comprises a superstructure and is supported by three implants. The computational model of mandibular bone and the implant prosthesis were constructed based on patient-specific computerized tomography (CT) images and Computer Aided Design (CAD) tools. To better reflect the real clinical situation, the 3D real-time loading data of maximum voluntary clenching measured using piezo-electric force transducers in patient were adopted in the 3D finite element (FE) analyses (FEA). The von Mises equivalent stress, maximum shear stress, equivalent strain and strain energy density in the peri-implant bone regions are quantified. The peak stresses and strains in the peri-implant bone were observed around the neck of the implant, indicating risk of micro-motion and bone resorption. In this study, we successfully conducted a computational simulation in silico based on in vivo 3D force measurement of a specific patient. The results provided important biomechanical data for clinical treatment, potentially helping enhancing the longevity and reliability of the implant-supported FPD restoration.

Abstract: Stress distributions that occur in the free end second premolar tooth and its root form dental implant replacement were evaluated using finite element method. In the modelling process, 3D reconstructions were performed. Instead of doing it manually, the 3D reconstruction in this paper was done using cone beam computed tomography (CBCT) scanning process. The 3D reconstruction method used in this paper, is considerably faster than the traditional manual 3D reconstruction method. In order to mimic the actual biting force, static load of 200 N was modelled in the vertical direction parallel to the long axis of the tooth which is placed on bite contact at second premolars and dental implant crown. The stress result on root form dental implant is generally higher than the stress on the natural free end second premolar tooth. The stress concentration locations on root form dental implant were also found and will be used in the future to improve the design of root form dental implant.

Abstract: The ability to achieve predictable results in oral implantology depends on indepth knowledge of all factors affecting bone healing, as well as on implant characteristics and the mechanical forces involved in immediate loading. The success of the immediate loading protocol relies on three main factors: (1) primary stability, which limits micromotion of the implant, (2) secondary biologic stability, resulting in osteogenesis in the peri-implant area, and (3) the control of bone resorption caused by deleterious loading forces that lead to implant instability during healing. Activated platelets play a crucial role in peri-implant healing and the use of Plasma Rich in Growth Factors (PRGF) in association with immediate implant placement could be a viable therapeutic option for the reabilitation of postextraction sockets. In our case-study, the implants and the abutments were welded with a titanium bar in order to provide predictable fixation and immobility of implants in early stages of bone healing. The implants have been properly integrated at both the bone and gingiva levels allowing the patient to resume both esthetic and masticatory functions from the very day the implants are inserted.

Abstract: The article presents the experience of a new therapeutic method, addressing postoperative implant pathology.Methods: Hyaluronic acid has been used in the management of various mucoperiosteal pathologies (directing secondary healing of oral wounds, restoration / increasing the volume of connective tissue – periosteal preoperativ or the papillary volume).Hyaluronic acid used had different concentration. The presentation forms both viscous and fluid particle size and type/acid’s grade of complexation) provided various therapeutic effects with specific indication of administration respected by the authors. Different products available at this time in Romania were used analyzing the results in time.Results: This therapeutic approach provided a good management in secondary granulation and wound healing of oral tissues in difficult cases (GBR, implant therapy) in which the persistence of dehiscence wound can cause a failure of surgical treatment (loss of membrane, alloplastic material or implant).Conclusion: This results places this innovative therapeutic method with others successful therapeutic solutions in usual dental practice, providing a quick and efficient settlement of some difficult clinical cases.

Abstract: The major goal of our research work is to develop an effective and efficient procedure to prepare surfaces with an average surface roughness R_a of 1...2,5 μm and a proper surface topography, as the morphology of dental implant surface is of extreme importance in the process of implant osseointegration. The aim of present research was to elucidate the effect of surface preparation and passivation treatment on topography of Ti6Al4V surfaces for dental implants, and to perform an efficient procedure, in terms of process time. Thirty samples were prepared, some samples were subjected to sand blasting, all samples were acid etched using a dual bath of H₂SO₄ 1n and HCl 1n (1:1) at different temperatures (60°C, 80°C, and 100°C) using different process durations (1 h, 3 h, 6 h, 12 h, and 24 h). After acid etching procedure some samples were passivated in 30% HNO₃ at room temperature, for 15 min. Scanning electron microscopy was performed in order to characterize the topography of the surfaces. We found that sand blasting and passivation treatment promotes the formation of a proper surface topography with large, smooth valleys (∼50 μm), different size large peaks (∼30 μm), and micropores (<10 μm) opened on the surface of valleys and peaks, required by a good osseointegration. We showed that the same proper morphology can be achieved by acid etching at different temperatures, using different process duration. The most efficient procedure takes place at 100°C, with process times of 1...3 hours.

Abstract: The stress distribution in cortical bone and dental implant has been modeled by finite element method (FEM) using linear static analysis in the case of monocortical and bicortical fixation of a real dental implant for three cortical bone thicknesses: 2 mm, 2.5 mm, 4 mm. The analysis revealed that the highest stresses in the cortical bone and in the implant after three-axial loading are localized at the edge of the cortical bone near the implant neck where bending moment is the highest. An increase of the maximum stresses has been observed with the decrease of the intraosseal length of the implant and cortical bone thickness.

Abstract: The aim of this work is the description of microstructure and comparison of micromechanical properties of cylindrical shaped intraosseous parts of dental implants with plasma modified surface and with threaded modification. Differences in elastic parameters (such as reduced modulus (E_r) and hardness (H)) of investigated implants within the supporting part of the shaft and surface layer in two different directions (proximal and lateral) are compared using experimental method of nanoindentation. Machined implants of titanium alloys Ti6Al4V with plasma modified surface of sprayed titanium with hydroxyapatit (HA) Ca₁₀(PO₄)₆(OH)₂ from different batches of product were available for measurements. SEM element analysis revealed a heterogeneous structure and various concentrations of the essential chemical elements (C, O, P, Ca) on the surface of implants. Results of elastic moduli and hardness was monitored in different locations. On a large statistical set of measurements was indicated that average reduced modulus of implant shafts of titanium alloy is approximately 126 GPa. Differences of E_r in case of peripheral hydroxyapatite layer are in range of ~145 GPa – ~163 GPa according to the exact composition of surface modification in the individual batches of the product. The difference of measured values on individual samples in a proximal/lateral direction is approximately 10%.

Abstract: This paper focused on optimal stress distribution in the mandibular bone surrounding a dental implant and devoted to the development of a modified Osteoplant implant type in order to minimize stress concentration in the bone/implant interface. This study investigated two elastomeric stress barriers incorporated into the dental implant using 3-D finite element analysis. Overall, this proposed implant provoked lower bone/implant interface stresses due to the effect of the elastomers as stress absorbers.Key Words: Dental implant, stress absorber, elastomer, finite element method