Papers by Keyword: Dental Implant

Abstract: The osseointegration capability of titanium dental implants is related to their chemical composition and surface roughness. In this study, the combination of grit-blasting and micro-arc oxidation had been used for producing the improved implant surfaces. The ceramic particles were projected to titanium dental implants through a nozzle at high velocity by means of compressed air to get high surface roughness. Then the surface of titanium implants was modified by micro-arc oxidation treatment. The current density, frequency and duty were 50-300 mA/cm2, 100 Hz, and 50%, respectively. A porous TiO2 layer was formed on the surface after the oxidation treatment. The surface structure of oxidized implants exhibited nanometer-sized pores with an average diameter of 0.2 µm. The TiO2 passive layer of the implant surface can attribute to the excellent biocompatibility. The high roughness (Ra=0.182 µm) formed by grit-blasting maximizes the interlocking between mineralized bone and the surface of the implant. Surface roughness in the manometer range formed by micro-arc oxidation treatment would play an important role in the adsorption of proteins, adhesion of osteoblastic cell and thus the rate of osseointegration.

Abstract: This paper provides a preliminary understanding in biomechanics with respect to a fullyporous- coated (FPC) dental implant. A 2D multiscale finite element model is created for a typical dental implantation setting. Under a certain mastication force (<200N), a global response is first obtained from a macro-scale model (without coated surface morphology details), and then it is transferred to a micro-scale model (with coated surface morphology details), which allows determining a local biomechanical field. To facilitate the study in bone remodelling, strain energy density and equivalent strain are analysed respectively. Different porosities of coating are taken into account in this study to investigate the effect of FPC materials on these typical remodelling stimuli. The results evidently reflect the osseointegrative benefits generated from surface coating. The result reveals that increasing in particle sizes has significant effect on biomechanical response.

Abstract: Surface roughness modulates the osseointegration of orthopaedic and dental titanium implants. High surface roughness is currently obtained by blasting of titanium implants with silica or aluminium abrasive particles. This process includes into the surface abrasive particles and may cause the release of cytotoxic silica or aluminium ions in the peri implant tissue. To overcome this drawback, we currently develop an innovative gridblasting process using Biphasic Calcium Phosphate (BCP) particles (RBBM Resorbable and Biocompatible Blast Media) to generate biocompatible roughened titanium surface. This work present the technique of blasting using RBBM particles to provide a roughened surface which does not release cytotoxic elements and (ii) to assess the effects of such a roughened surface for bone osteointegration in critical size rabbit defect. Our results demonstrate that resorbable biphasic calcium phosphate abrasive particles can be used to create titanium surface roughness. This grid blasting process increases surface roughness of titanium implants and offers a non cytotoxic surface for rapid and efficient osteointegration.

Abstract: The purpose of treatment for peri-implantitis is to achieve structural and functional restoration of the lost supporting tissues around implants, including re-osseointegration. Both surgical and non-surgical approaches in combination with a variety of anti-microbial treatment regimens have been applied depending on the size and shape of the bone defect. Tetracycline-HCl (Tc) treatment has been considered as a effective chemical modality for decontamination and detoxification of contaminated implant surfaces. The aim of this study was to examine if Tc conditioning changes the microstructures of the modified surface of dental implants. Dental implants with (1) hydroxyapatite-coated surface (HAS) (Replace® select HA, Nobel Biocare AB, Göthenburg, Sweden), (2) TiO2-blasted surface (TBS) (Astra TiOblast®, ASTRA Tech AB, Mölndal, Sweden) were used in this study. Tc treatment noticeably altered the surface of HAS and TBS. HAS and TBS were partially removed from the implant surface as early as 90 and 60 sec, respectively.

Abstract: The increased surface roughness of dental implants has shown enhanced integration of bone tissues to implant surfaces, but may be predisposed to an increased risk of pathogenic bacterial infection and contamination with bacterial products. Tetracycline-HCl (Tc) treatment has been regarded as a practical and effective chemical modality for decontamination and detoxification of contaminated implant surfaces. The purpose of this study was to examine if Tc treatment alters the microstructures of the modified surface of dental implants. For this purpose, dental implants with pure titanium machined surface (MS), sandblasted, large grit, acid-etched surface (SLAS), or anodized surface (AS) were used. The surface of dental implants was rubbed for 30, 60, 90, 120, or 150 sec with sponge pellets soaked in Tc solution (50mg/ml) and in distilled water for 0 and 150 sec as the control group. The specimens were then routinely processed for scanning electron microscopy. The results show that Tc treatment did not change the surface of MS, SLAS, and AS.

Abstract: Dental implants have been extensively used in prosthetic dentistry over the last two decades. Clinical experience shows that the healing and osseointegration process can heavily influence the success of the implantation. It is critical to understand the damage extent in different time frames. This paper aims at exploring the mechanical damage of dental implantation over the healing process. The 3D finite element analysis (FEA) models were developed based on computerised tomography (CT) scan technology to investigate the load-induced damage of interfacial osseointegration, as well as cortical and cancellous bone tissues. Unlike the existing linear finite element (FE) stress analysis, this study takes into account the damage accumulation and micro-crack nucleation under a framework of bone/interface remodelling. This study reveals the damage in the surrounding bone tissues and bone-implant interfaces at different stages of the healing process, and consequently premature load tolerances are suggested.

Abstract: Osseointegrated titanium implants have been widely used in clinics for replacement of missing teeth. However, sensory perception thresholds of implants were 10 to 100 times higher than those of natural teeth. The purpose of this study was to evaluate the effect of the ceramic coating generated by microarc oxidation (MAO) on sensory reconstruction around dental implants. The MAO coating was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and scanning probe microscope (SPM). Moreover, the chemical composition was analyzed with an energy dispersive spectroscope (EDS). Using smooth titanium discs as a control, Schwann cell responses to the coating were evaluated by SEM, MTT assay, total protein content and leakage of cytosolic lactate dehydrogenase (LDH) activity. In addition, the amount of brain-derived neurotrophic factor (BDNF) secreted by Schwann cells was measured by Enzyme-Linked Immunosorbent Assay (ELISA). It was observed that the porous coating had separated and homogeneous micropores in the diameter of 1-2 μm. The concentrations of Ca and P in the layer were 8.63% and 5.23% respectively. The cell morphology, proliferation and secretion of BDNF were unaffected. The results indicated that the MAO ceramic coating developed on the surface of pure titanium had good biocompatibility with Schwann cells for sensory reconstruction around dental implants.

Abstract: Twenty implants of 3.75mm in diameter(Neoplant, Neobiotech, Korea) were used to evaluate the correlation between the resonance frequency analysis (RFA) and the radiographic method for periimplant bone change under in vitro conditions. To simulate peri-implant bone change, 2mm-deep 45° range horizontal defect and 2mm-deep 90° range horizontal defect area were serially prepared perpendicular to the X-ray beam after conventional implant insertion. ISQ values and gray values inside threads were measured before and after peri-implant bone defect preparation. ISQ value of resonance frequency analysis was changed according to peri-implant bone change and gray value of radiographic method was changed according to peri-implant bone change. In horizontal defect condition, relatively positive correlation were between ISQ and gray values(r=0.663).