Commercial Dental Implants Research Articles

Experimental investigation of commercial small diameter dental implants in porcine mandibular segments.

Small diameter (mini) dental implants have become more popular in recent years as alternatives to classical implant treatment in clinical cases with critical bony situations. However, an in-depth scientific analysis of the mechanical and biomechanical effects of small diameter implants has not yet been published. The aim of the present study was to investigate experimentally different commercial mini implants by measuring their displacements under immediate loading. Twelve commercially available mini implants were measured. Implants were inserted into porcine mandibular segments and loaded by means of a predefined displacement of 0.5 mm of the loading system. The implants were loaded at an angle of 30° to the implant long axis using the self-developed biomechanical hexapod measurement system. Implant displacements were registered. The experimental results were compared to the numerical ones from a previous study. Measured implant displacements were within the range of 39-194 μm. A large variation in the displacements was obtained among the different implant systems due to the different designs and thread profiles. Comparing experimental and numerical results, the displacements that were obtained numerically were within the range of 79-347 μm. The different commercial mini implants showed acceptable primary stability and could be loaded immediately after their insertion.

Potential use of a polycarbonate-urethane matrix reinforced with polyethylene fibers for shock-absorbing dental implants

The absence of a shock-absorbing mechanism in commercial dental implants is a likely factor in the resulting bone loss and possible implant failure. The aim of the current study is to generate a shock-absorbing dental implant that resembles the periodontal ligament, which naturally absorbs occlusal overloading forces. To achieve this, a polycarbonate-urethane composite reinforced with polyethylene fibers will be constructed. Tests based on finite element analysis and mechanical testing are proposed to further examine this novel implant type.

Corrosion Behavior of Ti and Ti Based Alloys Used as Implants-Supported Mandibular Overdentures

In the present study, four different types of the commercial dental implants used as support for total/partial dental prosthesis have been investigated. Pure Ti and Ti6Al4V alloy, provided by four different manufactures, were chosen because these were the most used in dentistry market. The corrosion resistance was evaluated by using linear polarization technique, after recording the open circuit curves in Fusayama Meyer artificial saliva for 240 minutes. The corrosion tests in artificial saliva with pH 5.2 have shown that pure Ti exhibited a better behavior than the Ti alloy. This result can be explained by a higher stability of the passive thin layer of titanium oxide than the complex oxide layer formed on the Ti alloy surface.

In Vitro Investigation of the Effect of Oral Bacteria in the Surface Oxidation of Dental Implants.

Bacteria are major contributors to the rising number of dental implant failures. Inflammation secondary to bacterial colonization and bacterial biofilm is a major etiological factor associated with early and late implant failure (peri-implantitis). Even though there is a strong association between bacteria and bacterial biofilm and failure of dental implants, their effect on the surface of implants is yet not clear. To develop and establish an in vitro testing methodology to investigate the effect of early planktonic bacterial colonization on the surface of dental implants for a period of 60 days. Commercial dental implants were immersed in bacterial (Streptococcus mutans in brain-heart infusion broth) and control (broth only) media. Immersion testing was performed for a period of 60 days. During testing, optical density and pH of immersion media were monitored. The implant surface was surveyed with different microscopy techniques post-immersion. Metal ion release in solution was detected with an electrochemical impedance spectroscopy sensor platform called metal ion electrochemical biosensor (MIEB). Bacteria grew in the implant-containing medium and provided a sustained acidic environment. Implants immersed in bacterial culture displayed various corrosion features, including surface discoloration, deformation of rough and smooth interfaces, pitting attack, and severe surface rusting. The surface features were confirmed by microscopic techniques, and metal particle generation was detected by the MIEB. Implant surface oxidation occurred in bacteria-containing medium even at early stages of immersion (2 days). The incremental corrosion resulted in dissolution of metal ions and debris into the testing solution. Dissolution of metal ions and particles in the oral environment can trigger or contribute to the development of peri-implantitis at later stages.

Effects of implant neck design on primary stability and overload in a type IV mandibular bone.

This study investigates the effect of implant neck design on primary stability and overload using 3D finite element analysis. Four commercial dental implants and mandibular segments are created. Various parameters including the osseointegration condition (non-osseointegration and full osseointegration), force direction (vertical and horizontal), and cortical bone thickness (Tc = 0.3, 0.5, and 1 mm) are considered. The vertical and horizontal forces, 500 N and 250 N, are statically applied at the top of the platform, respectively. Micromotion and von Mises stress are employed to evaluate the risk of osseointegration and bone fatigue before osseointegration condition. After osseointegration, the principal stress is used to analyze the bone overload. Maximal von Mises stress and micromotion of the peri-implant bone decreased as cortical bone thickness increased. Horizontal force induces stress concentration in the bone around the implant neck easier than that of vertical force, and it may result in crestal bone loss. Thinner cortical bone should avoid dental implantation because it causes a noteworthy larger micromotion and stress concentration in cortical bone in particular Tc less than 0.3 mm.

Antibacterial effects and biocompatibility of titanium surfaces with graded silver incorporation in titania nanotubes

Most commercial dental implants are made of titanium (Ti) because Ti possesses excellent properties such as osseointegration. However, many types of Ti products still suffer from insufficient antibacterial capability and bacterial infection after surgery remains one of the most common and intractable complications. In this study, a dual process encompassing anodization and silver plasma immersion ion implantation (Ag PIII) is utilized to produce titania nanotubes (TiO2-NTs) containing Ag at different sites and depths. The concentration and depth of the incorporated Ag can be tailored readily by changing the PIII parameters. The Ag-embedded TiO2-NTs which retain the nanotubular morphology are capable of sterilizing oral pathogens as opposed to pure Ti plates and pristine TiO2-NTs. Biological assays indicate that the in vitro and in vivo biocompatibility of the sample plasma-implanted at a lower voltage of 0.5 kV (NT-Ag-0.5) is significantly compromised due to the large amount of surface Ag. On the other hand, the sample implanted at 1 kV (NT-Ag-1.0) exhibits unimpaired effects due to the smaller surface Ag accumulation. Sample NT-Ag-1.0 is further demonstrated to possess sustained antibacterial properties due to the large embedded depth of Ag and the technique and resulting materials have large potential in dental implants.

Finite Element Analysis of Dental Implant Neck Effects on Primary Stability and Osseointegration in a Type IV Bone Mandible

The purpose of this study is to investigate the effect of implant neck design and cortical bone thickness by means of 3-D linearly elastic finite element analysis and to analyze primary and secondary stability of clinical evidence based on micromotion and principal stress. Four commercial dental implants, comparable in size, for a type IV bone and mandibular segments were created. Various parameters were considered, including the osseointegration condition (non- and full bonded), force direction (vertical and horizontal) and cortical bone thickness (0.3, 0.5 and 1mm). The force was considered a static load applied at the top of the platform. The magnitudes of the vertical and horizontal loading direction were 500 N and 250 N. Micromotion and principal stresses were employed to evaluate the failure of osseointegration and bone overloading, respectively. The results show that Maximum stress of the peri-implant bone decreased as cortical bone thickness increased. The stress concentration regions were located at the implant neck between the cortical bone and cancellous bone. The micromotion level in full osseointegration is less than that in non-osseointegration and it also decreases as a increasing of cortical bone thickness. Consequently, cortical bone thickness is a key factor for primary stability.

Photofunctionalization Enhances Bone-Implant Contact, Dynamics of Interfacial Osteogenesis, Marginal Bone Seal, and Removal Torque Value of Implants

Ultraviolet (UV) light treatment of titanium, ie, photofunctionalization, has been extensively reported to enhance the osteoconductivity of titanium in animal and in vitro studies. This is the first study to examine whether photofunctionalization is effective on commercial dental implants in vivo. Dental implants with a microroughened surface were placed into dog jawbones. Photofunctionalization was performed by treating implants with UV light for 15 minutes using a photo device immediately before placement. Four weeks after placement, bone-implant integration was evaluated using a removable torque test and static and dynamic histology. Implant surfaces were converted from hydrophobic to super-hydrophilic after photofunctionalization. Removable torque for photofunctionalized implants was significantly higher by 50% than that for untreated implants. Bone-implant contact (BIC) was significantly higher for photofunctionalized implants in all zones examined: marginal, cortical, and bone marrow zones. An intensive mineralized layer was exclusively present in marginal bone at photofunctionalized interface. Dynamic histology identified early-onset, long-lasting robust bone deposition at photofunctionalized interface. Photofunctionalization enhanced the morphology, quality, and behavior of periimplant osteogenesis, including the increased BIC, expedited robust interfacial bone deposition, and improved marginal bone seal and support.

Surface Characteristics and Cell Adhesion: A Comparative Study of Four Commercial Dental Implants

The aims of this study were to compare surface properties of four commercial dental implants and to compare those implant systems' cell adhesion, which may be affected by the surface properties, and to provide scientific information on the selection of implants for clinicians. The surface properties of four commonly used dental implants (3i Nanotite™, Astra OsseoSpeed™, Nobel Biocare TiUnite®, and Straumann SLActive®) were studied using MicroSpy profiler, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy, and Raman microspectroscopy. Primary mouse alveolar bone cells were cultured on the surface of implants from the four companies. After 48-hour culture, SEM in combination with a quantitative analysis of SEM images was used to examine the cell adhesion. Cell adhesion rates (ratios of cell surface to implant surface) among different systems were compared. Distinct differences were found among these implants. Comparisons of roughness among three locations: flank, top, and valley within the same implant system, or in the same location among different implants were made. Generally Astra and Straumann systems showed the roughest surface, whereas 3i showed the smoothest surface. Multiple cracks were found on the surface of the Nobel Biocare system, which also had a dramatically lower level of titanium. In addition, rutile phase of titanium oxide was found in 3i, Astra, and Straumann systems, and anatase phase of titanium oxide was only detected in the Nobel Biocare system. After 48-hour culture, Astra and Straumann systems displayed the highest cell adhesion at the areas of flank, top, and valley of the implant surface. Primary cells also reached confluence on the valley, but significantly less in the 3i system. Nobel Biocare showed the least cell adhesion on the flank and valley. Implant systems have distinct differences in surface properties, leading to different cell adhesion results. Further in vivo study is needed to study the impact of the surface characteristics and different cell adhesion on the osseointegration between implant and bone.

Photofunctionalized Dental Implants: A Case Series in Compromised Bone

Ultraviolet (UV) light treatment of titanium, or photofunctionalization, has been shown to enhance its osteoconductivity in animal and in vitro studies, but its clinical performance has yet to be reported. This clinical case series sought to examine the effect of photofunctionalization on implant success, healing time, osseointegration speed, and peri-implant marginal bone level changes at 1 year after restoration. Four partially edentulous patients were included in the study. Seven implants with identical microroughened surfaces were photofunctionalized with UV light for 15 minutes. Osseointegration speed was calculated by measuring the increase in implant stability quotient (ISQ) per month. Marginal bone levels were evaluated radiographically at crown placement and at 1 year. All implants placed into fresh extraction sockets, vertically augmented bone, simultaneously augmented sinuses, or the site of a failing implant remained functional and healthy at 1 year, even with an earlier loading protocol (2.1 to 4.5 months). ISQs of 48 to 75 at implant placement had increased to 68 to 81 at loading. In particular, implants with low primary stability (initial ISQ < 70) showed large increases in ISQ. The speed of osseointegration of photofunctionalized implants was considerably greater than that of as-received implants documented in the literature. Mean marginal bone levels were -0.35 ± 0.71 mm at crown placement and had significantly increased to 0.16 ± 0.53 mm at 1 year, with coronal gains in marginal bone level that surpassed the implant platform. No implants showed marginal bone loss. Within the limits of this study, photofunctionalization expedited and enhanced osseointegration of commercial dental implants in various clinically challenging/compromised bone conditions. Photofunctionalization resulted in preservation--and often a gain--of marginal bone level, and long-term large-scale clinical validation is warranted.

Finite element modelling of implant designs and cortical bone thickness on stress distribution in maxillary type IV bone

The aims of this study were to examine the effect of implant neck design and cortical bone thickness using 3D finite element analysis and to analyse the stability of clinical evidence based on micromotion and principal stress. Four commercial dental implants for a type IV bone and maxillary segments were created. Various parameters were considered, including the osseointegration condition, loading direction and cortical bone thickness. Micromotion and principal stresses were used to evaluate the failure of osseointegration and bone overloading, respectively. It was found that the maximum stress of the peri-implant bone decreased as cortical bone thickness increased. The micromotion level in full osseointegration is less than that in non-osseointegration and it also decreases as cortical bone thickness increases. The cortical bone thickness should be measured before surgery to help select a proper implant. In the early stage of implantation, the horizontal loading component induces stress concentration in bone around the implant neck more easily than does the vertical loading component, and this may result in crestal bone loss.

Commercially Available Dental Implants: Review of Their Surface Characteristics

Titanium is widely used as an implant material in dentistry with excellent clinical results. The clinical success of the implants is often coupled to the surface properties of the implants. This review focuses on the available literature describing the surface characteristics of the most widely used commercial dental implants. The current commercially available dental implants all show differences in their surface characteristics, for example with regard to surface roughness, surface energy, and surface phase composition. Some surfaces lack published data while the characteristics of others are well described in the literature. However, more analysis by standardized techniques must be performed in order to fully understand which specific parameters are important for osseointegration and clinical success.

Life prediction of different commercial dental implants as influence by uncertainties in their fatigue material properties and loading conditions

Probabilistic analyses allow the effect of uncertainty in system parameters to be determined. In the literature, many researchers have investigated static loading effects on dental implants. However, the intrinsic variability and uncertainty of most of the main problem parameters are not accounted for. The objective of this research was to apply a probabilistic computational approach to predict the fatigue life of three different commercial dental implants considering the variability and uncertainty in their fatigue material properties and loading conditions. For one of the commercial dental implants, the influence of its diameter in the fatigue life performance was also studied. This stochastic technique was based on the combination of a probabilistic finite element method (PFEM) and a cumulative damage approach known as B-model. After 6 million of loading cycles, local failure probabilities of 0.3, 0.4 and 0.91 were predicted for the Lifecore, Avinent and GMI implants, respectively (diameter of 3.75mm). The influence of the diameter for the GMI implant was studied and the results predicted a local failure probability of 0.91 and 0.1 for the 3.75mm and 5mm, respectively. In all cases the highest failure probability was located at the upper screw-threads. Therefore, the probabilistic methodology proposed herein may be a useful tool for performing a qualitative comparison between different commercial dental implants.

Comparison Between Bioactive Fluoride Modified and Bioinert Anodically Oxidized Implant Surfaces in Early Bone Response Using Rabbit Tibia Model

The aim of this study was to investigate whether bioactive surfaces were more favorable to bone than bioinert surfaces by evaluating bone responses around two commercial dental implants. Bioactive fluoride-modified implants (Osseospeed) were compared with bioinert oxidized implants (TiUnite). Field emission scanning electron microscopy, energy dispersive spectroscopy, and confocal laser scanning microscopy analyzed the implant surface characteristics. Five New Zealand white rabbits were used to evaluate the bone response. Each rabbit received two implants: a fluoride-modified implant in one tibia and an oxidized implant in the other. Drilling was performed bicortically, and a gap defect was created in the upper cortexonly. Bone-to-implant contact and bone area were measured on the histological specimens 2 weeks after implant insertion. No significant differences were found in surface roughness (P > 0.05). The gap defects were almost filled with new bone within a period of 2 weeks. The histomorphometry revealed no significant differences in bone-to-implant contact and bone area (P > 0.05). Within the limitation of this study, the bioactive fluoride-modified surface may show no superiority to the bioinert anodized surface in early bone response.

Chemical and topographic analysis of treated surfaces of five different commercial dental titanium implants

We present a detailed investigation of the surface characteristics of five commercial titanium implants with different surface finishing (double acid etching, anodization and incorporation of Ca/P, acid etching and deposition of Ca/P, hydroxyapatite-blasting, acid etching and Ca/P-blasting) produced by five different manufacturers. A set of experimental techniques were employed to study the surface chemical composition and morphology: XPS, XRD, SEM, EDS, and AFM. According to the implat manufacturers, the addition of Ca and P at the implant surface is a main feature of these implants (except the double acid etched implant, which was included for comparative purpose). However, the results showed a great discrepancy on the final amount of these elements on the implant surface, which suggests a different effectiveness of the employed surface finishing methods to fix those elements on the implant surface. Our results show that only the method used by the manufacturer of hydroxyapatite-blasting surface finished implants was efficient to produce a hydroxyapatite coating. This group also showed the highest roughness parameters.

Stress-based performance comparison of dental implants by finite element analysis

The geometric shape of a dental implant plays an important role on the osteo-integration process. The purpose of this paper is to study the biomechanical behavior of different commercial dental implants and to analyse how thread profile may affect the stress concentration and distribution. Three different commercially-available dental implants were considered and acquired by means of a no-contact reverse engineering system. Stresses at bone–implant interface, in presence of perfect and not-perfect osteo-integration, were numerically evaluated by means of finite element (FEM) analyses applying occlusal and lateral loads. The results show more dangerous stresses at implant–bone interface in the case of not-perfect osteo-integration and stresses gradient enough uniform around the threads in the case of osteo-integration. In particular, the implant with the lowest thread-pitch exhibits the lowest bone damage. This confirms the crucial role of the geometric shape of the implant to reduce bone induced stresses and bone damage. The structural and functional connection between living bone and implant is a key issue in implantology field. When a guest device is installed in the living bone, many clinical responses may arise, such as inflammatory processes or osteo-integration failure. The results of this study can give useful information to understand the influence of the implant features and to appropriately apply it in the science of dental implants with the aim to reduce the potential implant failure.

Stress transfer properties of different commercial dental implants: a finite element study

Dental implantology has high success rates, and a suitable estimation of how stresses are transferred to the surrounding bone sheds insight into the correct design of implant features. In this study, we estimate stress transfer properties of four commercial implants (GMI, Lifecore, Intri and Avinent) that differ significantly in macroscopic geometry. Detailed three-dimensional finite element models were adopted to analyse the behaviour of the bone-implant system depending on the geometry of the implant (two different diameters) and the bone–implant interface condition. Occlusal static forces were applied and their effects on the bone, implant and bone–implant interface were evaluated. Large diameters avoided overload-induced bone resorption. Higher stresses were obtained with a debonded bone–implant interface. Relative micromotions at the bone–implant interface were within the limits required to achieve a good osseointegration. We anticipate that the methodology proposed may be a useful tool for a quantitative and qualitative comparison between different commercial dental implants.

Comparativein VitroStudy Among the Effects of Different Laser and LED Irradiation Protocols and Conventional Chlorhexidine Treatment for Deactivation of Bacterial Lipopolysaccharide Adherent to Titanium Surface

The present in vitro study was designed to evaluate and compare the efficacy of: 1) different dental laser devices used in photoablative (PA) mode, namely commercial CO(2), Er:YAG, and Nd:YAG lasers and a prototype diode laser (wavelength = 810 nm); 2) prototype low-energy laser diode or light-emitting diode (LED) (wavelength = 630 nm), used in photodynamic (PD) mode together with the photoactivated agent methylene blue; and 3) chlorhexidine, used as reference drug, to reduce the activation of macrophages by lipopolysaccharide (LPS), a major pro-inflammatory gram-negative bacterial endotoxin, adherent to titanium surface. RAW 264-7 macrophages were cultured on titanium discs, cut from commercial dental implants and precoated with Porphyromonas gingivalis LPS. Before cell seeding, the discs were treated or not with the noted lasers and LED in PA and PD modes, or with chlorhexidine. The release of nitric oxide (NO), assumed to be a marker of macrophage inflammatory activation, in the conditioned medium was related to cell viability, evaluated by the MTS assay and ultrastructural analysis. PA laser irradiation of the LPS-coated discs with Er:YAG, Nd:YAG, CO(2,) and diode (810 nm) significantly reduced NO production, with a maximal inhibition achieved by Nd:YAG and diode (810 nm). Similar effects were also obtained by PD treatment with diode laser and LED (630 nm) and methylene blue. Notably, both treatments were superior to chlorhexidine in terms of efficiency/toxicity ratio. These findings suggest that laser and LED irradiation are capable of effectively reducing the inflammatory response to LPS adherent to titanium surface, a notion that may have clinical relevance.

Variation of roughness and adhesion strength of deposited apatite layers on titanium dental implants

It is known that surface roughness and chemical composition of the titanium surface influence the osseointegration of titanium implants. Most commercial dental implants offer a shot-blasted rough surface. It is also known that apatite layers coating the surface of titanium implants improve bone response, but the adhesion of the layer to the substrate poses some problems.In this study the roughness and adhesion strength to a titanium dental implant surface of an apatite layer deposited via wet chemistry after a thermochemical treatment were compared with those of plasma-sprayed apatite layers and machined titanium surfaces. Different surface conditions have been studied: (a) as-received machined dental implant surface; (b) grit-blasted titanium surface; (c) grit-blasted and thermochemically-treated titanium surface; (d) titanium surfaces coated with plasma-sprayed apatite. The morphology and roughness of the samples were measured and compared. The adhesion of the apatite layers to the titanium was compared by means of a scratch test.Measured roughness showed that the deposition of an apatite layer did not affect roughness but plasma-sprayed apatite produced a decrease on roughness values when compared to control samples. Both roughness and adhesion strength of the deposited apatite layer to the titanium substrate were higher than those of the plasma-sprayed apatite.

Resonance frequency analysis and damping capacity assessment

The aims of this in vitro study were to evaluate reliability of the Osstell and Periotest devices in the assessment of implant stability and to perform a method comparison. Commercial dental implants were inserted into bovine rib segments of different anatomical origins and densities. Repeated measurements were performed, varying (a) the torque-in force of the devices' attachment screw (the Osstell transducer and the ball attachment, insert for the Periotest device), (b) the insertion site bone quality, and (c) the thread exposure in simulated peri-implant bone defects. Both methods were comparably reliable and showed a strong association to each other in the classification of implant stability. As opposed to torque-forced screw attachment, the variations in bone composition, differences in inter-implant stability of adjacent implants, and peri-implant bone reduction were statistically significant for both methods. Both non-invasive diagnostic devices seem to be useful in the long-term follow-up of implant integration.