In vitro fibroblast response to ultra fine grained titanium produced by a severe plastic deformation process

Commercially pure titanium modification to enhance corrosion behavior and osteoblast response by ECAP for biomedical applications

When it comes to using bio-metals, the chemical and biocompatibility properties of titanium led to its widespread use in biomedical implants. However, pure titanium possesses lower mechanical properties than Ti alloys containing cytotoxic elements. Severe plastic deformation (SPD) techniques were able to cause a significant strength increase, corrosion behavior improvement, and the release of the alloying elements. In this study, the ECAP process was performed on commercially pure titanium with a square cross-section at two and four passes, which resulted in a finer grain size and a more uniform microstructure. In order to improve cell behaviors, etch treatment was performed to produce nano-rough and nano-texture surfaces for all Ti samples. The effect of surface etching on corrosion, surface roughness, and cell behaviors on ECAP and untreated samples was also investigated. Optical/Field Emission Scanning Electron Microscopy, Atomic Force Microscopy, and X-Ray Diffraction were used to study the microstructural characterizations of samples. In addition, the impact of grain structure on the contact angle, electrochemical corrosion behavior, osteoblast response, and cell viability was investigated. The titanium that was ECAPed four times provided finer grains (200 nm) than the unprocessed sample (25 µm). The potentiodynamic polarization test revealed that corrosion resistance of ECAPed samples was enhanced, which was associated with grain refinement, affecting the passive film formation. Corrosion resistance and wettability experienced an apparent increase after each ECAP pass. In conclusion, improvement of grain size and surface roughness was due to the simultaneous effect of ECAP and etching treatment that led to the osteoblast response and cellular activity of samples.

Review on Grain Refinement of Metallic Materials to Regulate Cellular Behavior

Metallic materials have been widely used as orthopedic implants in clinics for their good mechanical, physical, and chemical properties, but their slow osseointegration rate is still one of the main issues causing implantation failure. Grain refinement has recently attracted wide attention for its effective improvement of cell–material interaction for biometals. In this review, the surface and bulk grain refinement mode and the influence of grain size reduction of various metallic materials including titanium, stainless steel, magnesium, zirconium, tantalum, and their alloys as well as NiTi shape memory alloys on the cell responses is summarized in detail. It is hoped that this review could help biomaterials-related researchers to understand the grain refinement of metallic materials in a timely manner, thus boosting the development of biomedical metals for clinical use.

Integration of collagen fibers in connective tissue with dental implant in the transmucosal region

Dental implants have been widely accepted as an ideal therapy to replace the missing teeth for its good performance in aspects of mechanical properties and aesthetic outcomes. Its restorative success is contributed by not only the successful osseointegration of the implant but also the tight soft tissue integration, especially the collagen fibers, in the transmucosal region. Soft tissue attaching to the dental implant/abutment is overall similar, but in some aspects distinct with that seen around natural teeth and soft tissue integration can be enhanced via several surface modification methods. This review is going to focus on the current knowledge of the transmucosal zone around the dental implants (compared with natural teeth), and latest strategies in use to fine-tune the collagen fibers assembly in the connective tissue, in an attempt to enhance soft tissue integration.

Is titanium alloy Ti-6Al-4 V cytotoxic to gingival fibroblasts-A systematic review

OBJECTIVES

Grade V titanium alloy (Ti-6Al-4 V) is a well-recognized metallic biomaterial for medical implants. There has been some controversy regarding the use of this alloy in medical devices in relation to the toxicity of vanadium. In Dentistry, Ti-6Al-4 V remains prevalent. This systematic review aims to evaluate the effects of Ti-6Al-4 V on cells relevant to oral environments such as gingival fibroblasts.

MATERIALS AND METHODS

A literature search was undertaken for relevant English language publications in the following databases: Dental and Oral Science, Medline and Web of Science. The electronic search was supplemented with a search of references.

RESULTS

After application of inclusion and exclusion criteria. A total of eight papers are included in this review. These papers were all in vitro studies and were categorized into whole implant, discs, or implant particles based on the type of test materials used in the studies.

CONCLUSION

Based on the analyses of the eight included studies in this review, if Ti-6Al-4 V as a material is unchallenged, i.e., as a whole implant in pH neutral environments, there appears to be little effect on fibroblasts. If Ti-6Al-4 V is challenged through corrosion or wear (particle release), the subsequent release of vanadium and aluminium particles has an increased cytotoxic effect in vitro in comparison to commercially pure titanium, hence concerns should be raised in the clinical setting.

Coinciding significance of the crystallographic orientation and nanostructuring on the biocompatibility of TZNT-Ag1 .5 alloy deformed by the cold rolling process

In this study, the simultaneous significance of the crystallographic texture and nanostructuring on the cytocompatibility of as-cast (Ti₅₅ Zr₂₅ Nb₁₀ Ta₁₀ )_98.5 -Ag_1.5 alloy (at. %, TZNT-Ag_1.5 ), subjected to cold rolling up to 90% reduction, along with the changes of Young's modulus and hardness under cold rolling were investigated. For this purpose, the as-cast and cold-rolled TZNT-Ag_1.5 alloy test specimens were analyzed by XRD, TEM, HRTEM, SEM, contact angle, nanoindentation, and OM techniques. Moreover, to evaluate the effect of severe cold deformation on the biocompatibility, MG-63 osteoblastic cell was cultured on the surface of 90% cold-rolled and as-cast test specimens of TZNT-Ag_1.5 alloy. The results showed that severe cold deformation was led to fast grain refinement of β grains of the as-cast TZNT-Ag_1.5 alloy in the range of 50-100 nm. In addition to the nanostructuring, upon severe cold deformation, the <gamma>-fiber (<111>// normal direction) texture was formed and after 90% reduction, the (111)<1 1 ¯ 0 > γ_-fiber component was strengthened. The micro-hardness and reduced Young's modulus are 235 ± 5.29, 246 ± 1.73, 271 ± 4.0, and 283 ± 6.25 (HV); and 73.725 ± 1.70, 83.98 ± 5.10, 81.26 ± 6.55, and 88.66 ± 7.16 (GPa) for TZNT-Ag_1.5 (as-cast), TZNT-Ag_1.5 (20%CR), TZNT-Ag_1.5 (50%CR), and TZNT-Ag_1.5 (90%CR) test specimens, respectively. Further, with increasing the cold deformation degree, the dislocation density of TZNT-Ag_1.5 alloy increased as this parameter is 2.79 × 10¹⁵ (m^-2 ) for the 90%CR test specimen. On the other hand, the values of the contact angle for the 90%CR test specimen (46.2 ± 3.5°) exhibit a higher hydrophilic and wettable surface as compared to the other studied test specimens. After 5 days of incubation, osteoblastic cells on the surface of the 90% cold-rolled TZNT-Ag_1.5 test specimens revealed significant differences in cell proliferation and differentiation as compared to the as-cast alloy test specimens and/or CP-Ti. Finally, because the maximum orientation intensities were generally <3, it was deduced that grain refinement rather than the crystallographic texture plays a significant role in improving the surface biocompatibility of the new TZNT-Ag_1.5 alloy.

Microbial Decontamination and Antibacterial Activity of Nanostructured Titanium Dental Implants: A Narrative Review

Peri-implantitis is the major cause of the failure of dental implants. Since dental implants have become one of the main therapies for teeth loss, the number of patients with peri-implant diseases has been rising. Like the periodontal diseases that affect the supporting tissues of the teeth, peri-implant diseases are also associated with the formation of dental plaque biofilm, and resulting inflammation and destruction of the gingival tissues and bone. Treatments for peri-implantitis are focused on reducing the bacterial load in the pocket around the implant, and in decontaminating surfaces once bacteria have been detached. Recently, nanoengineered titanium dental implants have been introduced to improve osteointegration and provide an osteoconductive surface; however, the increased surface roughness raises issues of biofilm formation and more challenging decontamination of the implant surface. This paper reviews treatment modalities that are carried out to eliminate bacterial biofilms and slow their regrowth in terms of their advantages and disadvantages when used on titanium dental implant surfaces with nanoscale features. Such decontamination methods include physical debridement, chemo-mechanical treatments, laser ablation and photodynamic therapy, and electrochemical processes. There is a consensus that the efficient removal of the biofilm supplemented by chemical debridement and full access to the pocket is essential for treating peri-implantitis in clinical settings. Moreover, there is the potential to create ideal nano-modified titanium implants which exert antimicrobial actions and inhibit biofilm formation. Methods to achieve this include structural and surface changes via chemical and physical processes that alter the surface morphology and confer antibacterial properties. These have shown promise in preclinical investigations.

Biological Applications of Severely Plastically Deformed Nano-Grained Medical Devices: A Review

Metallic materials are widely used for fabricating medical implants due to their high specific strength, biocompatibility, good corrosion properties, and fatigue resistance. Recently, titanium (Ti) and its alloys, as well as stainless steel (SS), have attracted attention from researchers because of their biocompatibility properties within the human body; however, improvements in mechanical properties while keeping other beneficial properties unchanged are still required. Severe plastic deformation (SPD) is a unique process for fabricating an ultra-fine-grained (UFG) metal with micrometer- to nanometer-level grain structures. SPD methods can substantially refine grain size and represent a promising strategy for improving biological functionality and mechanical properties. This present review paper provides an overview of different SPD techniques developed to create nano-/ultra-fine-grain-structured Ti and stainless steel for improved biomedical implant applications. Furthermore, studies will be covered that have used SPD techniques to improve bone cell proliferation and function while decreasing bacterial colonization when cultured on such nano-grained metals (without resorting to antibiotic use).

Ultrahigh hardness and biocompatibility of high-entropy alloy TiAlFeCoNi processed by high-pressure torsion

Despite significant studies on mechanical properties of high-entropy alloys (HEAs), there have been limited attempts to examine the biocompatibility of these alloys. In this study, a lattice-softened high-entropy alloy TiAlFeCoNi with ultrahigh hardness (examined by Vickers method), low elastic modulus (examined by nanoindentation) and superior activity for cell proliferation/viability/cytotoxicity (examined by MTT assay) was developed by employing imperial data and thermodynamic calculations. The designated alloy after casting was processed further by high-pressure torsion (HPT) to improve its hardness via the introduction of nanograins, dislocations and order-disorder transformation. The TiAlFeCoNi alloy with the L2₁-BCC crystal structure exhibited 170-580% higher hardness and 260-1020% better cellular metabolic activity compared to titanium and Ti-6Al-7Nb biomaterials, suggesting the high potential of HEAs for future biomedical applications.

On the Use of Functionally Graded Materials to Differentiate the Effects of Surface Severe Plastic Deformation, Roughness and Chemical Composition on Cell Proliferation

Additive manufacturing allows the manufacture of parts made of functionally graded materials (FGM) with a chemical gradient. This research work underlines that the use of FGM makes it possible to study mechanical, microstructural or biological characteristics while minimizing the number of required samples. The application of severe plastic deformation (SPD) by surface mechanical attrition treatment (SMAT) on FGM brings new insights on a major question in this field: which is the most important parameter between roughness, chemistry and microstructure modification on biocompatibility? Our study demonstrates that roughness has a large impact on adhesion while microstructure refinement plays a key role during the early stage of proliferation. After several days, chemistry is the main parameter that holds sway in the proliferation stage. With this respect, we also show that niobium has a much better biocompatibility than molybdenum when alloyed with titanium.

Comprehensive Evaluation of the Properties of Ultrafine to Nanocrystalline Grade 2 Titanium Wires

This paper describes the mechanical properties and microstructure of commercially pure titanium (Grade 2) processed with Conform severe plastic deformation (SPD) and rotary swaging techniques. This technology enables ultrafine-grained to nanocrystalline wires to be produced in a continuous process. A comprehensive description is given of those properties which should enable straightforward implementation of the material in medical applications. Conform SPD processing has led to a dramatic refinement of the initial microstructure, producing equiaxed grains already in the first pass. The mean grain size in the transverse direction was 320 nm. Further passes did not lead to any additional appreciable grain refinement. The subsequent rotary swaging caused fine grains to become elongated. A single Conform SPD pass and subsequent rotary swaging resulted in an ultimate strength of 1060 MPa and elongation of 12%. The achieved fatigue limit was 396 MPa. This paper describes the production possibilities of ultrafine to nanocrystalline wires made of pure titanium and points out the possibility of serial production, particularly in medical implants.

Proliferation of Osteoblasts on Laser-Modified Nanostructured Titanium Surfaces

Nanostructured titanium has become a useful material for biomedical applications such as dental implants. Certain surface properties (grain size, roughness, wettability) are highly expected to promote cell adhesion and osseointegration. The aim of this study was to compare the biocompatibilities of several titanium materials using human osteoblast cell line hFOB 1.19. Eight different types of specimens were examined: machined commercially pure grade 2 (cpTi2) and 4 (cpTi4) titanium, nanostructured titanium of the same grades (nTi2, nTi4), and corresponding specimens with laser-treated surfaces (cpTi2L, cpTi4L, nTi2L, nTi4L). Their surface topography was evaluated by means of scanning electron microscopy. Surface roughness was measured using a mechanical contact profilometer. Specimens with laser-treated surfaces had significantly higher surface roughness. Wettability was measured by the drop contact angle method. Nanostructured samples had significantly higher wettability. Cell proliferation after 48 hours from plating was assessed by viability and proliferation assay. The highest proliferation of osteoblasts was found in nTi4 specimens. The analysis of cell proliferation revealed a difference between machined and laser-treated specimens. The mean proliferation was lower on the laser-treated titanium materials. Although plain laser treatment increases surface roughness and wettability, it does not seem to lead to improved biocompatibility.

Friction Stir Processing of Stainless Steel for Ascertaining Its Superlative Performance in Bioimplant Applications

Substrate-cell interactions for a bioimplant are driven by substrate's surface characteristics. In addition, the performance of an implant and resistance to degradation are primarily governed by its surface properties. A bioimplant typically degrades by wear and corrosion in the physiological environment, resulting in metallosis. Surface engineering strategies for limiting degradation of implants and enhancing their performance may reduce or eliminate the need for implant removal surgeries and the associated cost. In the current study, we tailored the surface properties of stainless steel using submerged friction stir processing (FSP), a severe plastic deformation technique. FSP resulted in significant microstructural refinement from 22 μm grain size for the as-received alloy to 0.8 μm grain size for the processed sample with increase in hardness by nearly 1.5 times. The wear and corrosion behavior of the processed alloy was evaluated in simulated body fluid. The processed sample demonstrated remarkable improvement in both wear and corrosion resistance, which is explained by surface strengthening and formation of a highly stable passive layer. The methylthiazol tetrazolium assay demonstrated that the processed sample is better in supporting cell attachment, proliferation with minimal toxicity, and hemolysis. The athrombogenic characteristic of the as-received and processed samples was evaluated by fibrinogen adsorption and platelet adhesion via the enzyme-linked immunosorbent assay and lactate dehydrogenase assay, respectively. The processed sample showed less platelet and fibrinogen adhesion compared with the as-received alloy, signifying its high thromboresistance. The current study suggests friction stir processing to be a versatile toolbox for enhancing the performance and reliability of currently used bioimplant materials.

Superior Pre-Osteoblast Cell Response of Etched Ultrafine-Grained Titanium with a Controlled Crystallographic Orientation

Ultrafine-grained (UFG) Ti for improved mechanical performance as well as its surface modification enhancing biofunctions has attracted much attention in medical industries. Most of the studies on the surface etching of metallic biomaterials have focused on surface topography and wettability but not crystallographic orientation, i.e., texture, which influences the chemical as well as the physical properties. In this paper, the influences of texture and grain size on roughness, wettability, and pre-osteoblast cell response were investigated in vitro after HF etching treatment. The surface characteristics and cell behaviors of ultrafine, fine, and coarse-grained Ti were examined after the HF etching. The surface roughness during the etching treatment was significantly increased as the orientation angle from the basal pole was increased. The cell adhesion tendency of the rough surface was promoted. The UFG Ti substrate exhibited a higher texture energy state, rougher surface, enhanced hydrophilic wettability, and better cell adhesion and proliferation behaviors after etching than those of the coarse- and fine-grained Ti substrates. These results provide a new route for enhancing both mechanical and biological performances using etching after grain refinement of Ti.

In vitro and in vivo studies of ultrafine-grain Ti as dental implant material processed by ECAP

The aim of this study was to investigate the surface characterization of ultrafine-grain pure titanium (UFG-Ti) after sandblasting and acid-etching (SLA) and to evaluate its biocompatibility as dental implant material in vitro and in vivo. UFG-Ti was produced by equal channel angular pressing (ECAP) using commercially pure titanium (CP-Ti). Microstructure and yield strength were investigated. The morphology, wettability and roughness of the specimens were analyzed after they were modified by SLA. MC3T3-E1 osteoblasts were seeded onto the specimens to evaluate its biocompatibility in vitro. For the in vivo study, UFG-Ti implants after SLA were embedded into the femurs of New Zealand rabbits. Osseointegration was investigated though micro-CT analysis, histological assessment and pull-out test. The control group was CP-Ti. UFG-Ti with enhanced mechanical properties was produced by four passes of ECAP in BC route at room temperature. After SLA modification, the hierarchical porous structure on its surface exhibited excellent wettability. The adhesion, proliferation and viability of cells cultured on the UFG-Ti were superior to that of CP-Ti. In the in vivo study, favorable osseointegration occurred between the implant and bone in CP and UFG-Ti groups. The combination intensity of UF- Ti with bone was higher according to the pull-out test. This study supports the claim that UFG-Ti has grain refinement with outstanding mechanical properties and, with its excellent biocompatibility, has potential for use as dental implant material.

Second-phase-dependent grain refinement in Ti-25Nb-3Mo-3Zr-2Sn alloy and its enhanced osteoblast response

Ti-25Nb-3Mo-3Zr-2Sn (TLM) substrates, which consist of pure β phase and duplex α+β phases were achieved by different heat treatment. Different substrates with and without α phase were subjected to surface mechanical attrition treatment (SMAT) for 5 and 30 min, respectively. Investigated by transmission electron microscopy (TEM), it is found that the content and morphology of α phase in the TLM substrates play crucial roles in nanocrystallization of the alloy. During SMAT, the substrates composed of duplex α+β phases are much easier to nanocrystallized than that composed of pure β phase, and the duplex-phase substrate containing 35 vt.% α needles is more inclined to grain refinement than those substrates containing 27 vt.% α cobbles and 31 vt.% α needles. Accompanied with the nanocrystallization in the surface layers of the duplex-phase substrates, the stress induced α-to-β phase transition occurs. In addition, employing hFOB1.19 cells, the behaviors of osteoblasts on the unSMATed and as-SMATed surfaces were evaluated by examining the morphology and viability of the cells. It shows that the SMAT-induced grain refinement in the surface layer of the alloy can significantly improve the osteoblast response. Our study lays the foundation for nanostructuring β titanium alloys to be used as biomedical implants.

Correlation between properties and microstructure of laser sintered porous β-tricalcium phosphate bone scaffolds

A porous β-tricalcium phosphate (β-TCP) bioceramic scaffold was successfully prepared with our homemade selective laser sintering system. Microstructure observation by a scanning electron microscope showed that the grains grew from 0.21 to 1.32 μm with the decrease of laser scanning speed from 250 to 50 mm min^-1. The mechanical properties increased mainly due to the improved apparent density when the laser scanning speed decreased to 150 mm min^-1. When the scanning speed was further decreased, the grain size became larger and the mechanical properties severely decreased. The highest Vickers hardness and fracture toughness of the scaffold were 3.59 GPa and 1.16 MPa m^1/2, respectively, when laser power was 11 W, spot size was 1 mm in diameter, layer thickness was 0.1-0.2 mm and laser scanning speed was 150 mm min^-1. The biocompatibility of these scaffolds was assessed in vitro with MG63 osteoblast-like cells and human bone marrow mesenchymal stem cells. The results showed that all the prepared scaffolds are suitable for cell attachment and differentiation. Moreover, the smaller the grain size, the better the cell biocompatibility. The porous scaffold with a grain size of 0.71 μm was immersed in a simulated body fluid for different days to assess the bioactivity. The surface of the scaffold was covered by a bone-like apatite layer, which indicated that the β-TCP scaffold possesses good bioactivity. These discoveries demonstrated the evolution rule between grain microstructure and the properties that give a useful reference for the fabrication of β-TCP bone scaffolds.

Corrosion and in vitro biocompatibility properties of cryomilled-spark plasma sintered commercially pure titanium

Ti alloys, such as Ti6Al4V, are currently used in biomedical and dental implant applications. Ti alloys are used because they are stronger than commercially pure (CP) Ti due to the presence of alloying elements. However, toxicity of alloying elements during long-term use of implants is of concern. Another means of increasing the strength of materials is grain size refinement. In this study, ultrafine-grained (UFG, ~250 nm to 1 μm) CP Ti was produced by cryomilling followed by spark plasma sintering (SPS). Electrochemical impedance spectroscopy (EIS) and cell culture experiments were performed to compare the corrosion and biocompatibility properties of coarse grained (CG) Ti and UFG Ti. It was found that UFG Ti exhibited corrosion resistance comparable to CG Ti in Ringers solution. In addition, UFG Ti exhibited a reduced inflammatory response and enhanced cell adhesion compared to CG Ti. Investigation of surface roughness provided an explanation for enhanced cell adhesion.

Regulation of the behaviors of mesenchymal stem cells by surface nanostructured titanium

The study describes the influence of surface nanostructured titanium substrates on the growth behaviors of mesenchymal stem cells. Surface nanostructures of titanium were produced with surface mechanical attrition treatment (SMAT) technique. The morphologies of native titanium and surface nanostructured titanium substrates were characterized by field emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and contact-angle measurements, respectively. A thin nanostructured layer was formed onto the surfaces of titanium substrates after SMAT treatment. The effects of the surface nanostructured titanium substrates on the adhesion, spreading, proliferation and differentiation of mesenchymal stem cells (MSCs) was examined at cellular and molecular levels in vitro. The results suggest that the surface nanostructured substrates were beneficial for the growth of MSCs, including adhesion, filament orientation, proliferation and gene expression. This approach for the fabrication of surface nanostructured titanium may be exploited in the development of high performance titanium-based implants.

Corrosion fatigue of biomedical metallic alloys: mechanisms and mitigation

Cyclic stresses are often related to the premature mechanical failure of metallic biomaterials. The complex interaction between fatigue and corrosion in the physiological environment has been subject of many investigations. In this context, microstructure, heat treatments, plastic deformation, surface finishing and coatings have decisive influence on the mechanisms of fatigue crack nucleation and growth. Furthermore, wear is frequently present and contributes to the process. However, despite all the effort at elucidating the mechanisms that govern corrosion fatigue of biomedical alloys, failures continue to occur. This work reviews the literature on corrosion-fatigue-related phenomena of Ti alloys, surgical stainless steels, Co-Cr-Mo and Mg alloys. The aim was to discuss the correlation between structural and surface aspects of these materials and the onset of fatigue in the highly saline environment of the human body. By understanding such correlation, mitigation of corrosion fatigue failure may be achieved in a reliable scientific-based manner. Different mitigation methods are also reviewed and discussed throughout the text. It is intended that the information condensed in this article should be a valuable tool in the development of increasingly successful designs against the corrosion fatigue of metallic implants.

Accelerated stem cell attachment to ultrafine grained titanium

Commercial purity titanium with an average grain size in the low sub-micron range was produced by equal channel angular pressing (ECAP). Attachment of human bone marrow-derived mesenchymal stem cells (hMSCs) to the surface of conventional coarse grained and ECAP-modified titanium was studied. It was demonstrated that the attachment and spreading of hMSCs in the initial stages (up to 24h) of culture was enhanced by grain refinement. Surface characterization by a range of techniques showed that the main factor responsible for the observed acceleration of hMSC attachment and spreading on titanium due to grain refinement in the bulk is the attendant changes in surface topography on the nanoscale. These results indicate that, in addition to its superior mechanical properties, ECAP-modified titanium possesses improved biocompatibility, which makes it to a potent candidate for applications in medical implants.

Enhanced mechanical properties and in vitro cell response of surface mechanical attrition treated pure titanium

Surface mechanical attrition treatment (SMAT) was used to fabricate nanocrystalline surface layers on the commercial purity titanium. X-ray diffraction and transmission electron microscopy results indicate that the top layer contained nanograins. Enhanced strength and microhardness were achieved due to the surface nanostructure. Cell culture tests have shown a greater adhered cell density and more extensively spreading morphologies of Saos-2 cells on the SMAT substrates compared to those on the as-received Ti counterparts. Enhanced cell viability and cell cycle were also achieved on the SMAT Ti substrates. These could be attributed to the nanostructure grains with the increased surface hydrophilicity and roughness on the SMAT Ti.

Evaluation of functional dynamics during osseointegration and regeneration associated with oral implants

OBJECTIVES

The aim of this paper is to review current investigations on functional assessments of osseointegration and assess correlations to the peri-implant structure.

MATERIAL AND METHODS

The literature was electronically searched for studies of promoting dental implant osseointegration, functional assessments of implant stability, and finite element (FE) analyses in the field of implant dentistry, and any references regarding biological events during osseointegration were also cited as background information.

RESULTS

Osseointegration involves a cascade of protein and cell apposition, vascular invasion, de novo bone formation and maturation to achieve the primary and secondary dental implant stability. This process may be accelerated by alteration of the implant surface roughness, developing a biomimetric interface, or local delivery of growth-promoting factors. The current available pre-clinical and clinical biomechanical assessments demonstrated a variety of correlations to the peri-implant structural parameters, and functionally integrated peri-implant structure through FE optimization can offer strong correlation to the interfacial biomechanics.

CONCLUSIONS

The progression of osseointegration may be accelerated by alteration of the implant interface as well as growth factor applications, and functional integration of peri-implant structure may be feasible to predict the implant function during osseointegration. More research in this field is still needed.