AIM: Bendable and angulated single-piece implants are used alternatively to screwable abutments in two-piece dental implant designs. Though used frequently, data on the stress distribution within such implants are not available and the question whether the bending contributes to fracture resistance has not been addressed. METHODS: We used the method of finite element to identify von Mises stresses and maximum stresses in bent and non-bent but angulated implants. Implants with one (e.g. applicable to screw designs) or two (applicable to basal implants) bending areas were the variables under investigation. RESULTS: For bends up to 13 degrees we discovered that if there is only one bend, the maximum stress is in the bent area. If two bends are made in two different bending areas, the maximum stresses are distributed between the two and, if either one of the bent areas is machined, there are no residual stresses within the implant body in this area. The maximum stresses are always located near the base-plates. The absolute value of the maximum stress is higher because no residual stresses are available to compensate stresses that stem from loading. CONCLUSION: Assuming that all other parameters are equal, bendable (basal) implants show a more even stress distribution along the vertical implant region than identically shaped implants with a machine-angulated area. Bendable basal implants therefore probably resist masticatory forces better than pre-angulated, machined implants, and unbent implants which provide a thin region in the vertical implant area.

• MeSH
• analýza metodou konečných prvků MeSH
• analýza zatížení zubů * MeSH
• lidé MeSH
• pružnost MeSH
• techniky in vitro MeSH
• titan MeSH
• zubní implantáty * MeSH
• zubní materiály * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH
• Názvy látek
• titan MeSH
• zubní implantáty * MeSH
• zubní materiály * MeSH

BACKGROUND: Dental implants are a suitable option for the replacement of some or all missing teeth. Their main function is to secure the stability of the artificial tooth. The implant material interacts with several cell types including osteoblasts, gingival fibroblasts, periodontal ligament fibroblasts and monocytes. The most common material used is pure titanium which is corrosion resistant and has an elasticity modulus similar to that of bone. In recent years, diverse modified titanium surfaces have also been developed. The wound healing around the implant is a complex process that determines how well the host can heal and accept the implanted material. For this reason, search for markers of the biocompatibility of these new materials is paramount. To identify markers found to be suitable for studying the biocompatibility of dental implants. METHODS: Review of Pubmed and Web of Science databases for the years 1958-2010. CONCLUSIONS: The surface of dental implant material should enhance firm attachment of the implant to junctional epithelium, soft connective tissue and bone. For the purposes of dental implant biocompatibility studies, a number of markers produced by osteoblasts or by cells of periodontal ligament have been proposed. In general, the most typical markers for osteoblasts and fibroblasts are alkaline phosphatase and collagen I, respectively. The involvement of both cell types in the inflammatory response is primarily evaluated by determination of tumour necrosis factor α and proinflammatory interleukins.

• MeSH
• alkalická fosfatasa metabolismus   MeSH
• biokompatibilní materiály * MeSH
• endoseální implantace zubů * MeSH
• fibroblasty metabolismus   MeSH
• gingiva metabolismus   MeSH
• hojení ran MeSH
• kolagen metabolismus   MeSH
• lidé MeSH
• osteoblasty metabolismus   MeSH
• periodontální vaz metabolismus   MeSH
• titan MeSH
• zubní implantáty * MeSH
• zubní materiály MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• alkalická fosfatasa MeSH
• biokompatibilní materiály * MeSH
• kolagen MeSH
• titan MeSH
• zubní implantáty * MeSH
• zubní materiály MeSH

Material-induced ossification is suggested as a suitable approach to heal large bone defects. Fiber-reinforced composite-bioactive glasses (FRC-BGs) display properties that could enhance the ossification of calvarial defects. Here, we analyzed the healing processes of a FRC-BG implant in vivo from the perspective of material-induced ossification. Histological analysis of the implant, which was removed 5 months after insertion, showed the formation of viable, noninflammatory mesenchymal tissue with newly-formed mineralized woven bone, as well as nonmineralized connective tissue with capillaries and larger blood vessels. The presence of osteocytes was detected within the newly generated bone matrix. To expand our understanding on the osteogenic properties of FRC-BG, we cultured human adipose tissue-derived mesenchymal stromal cells (AD-MSCs) in the presence of two different BGs (45S5 and S53P4) and Al2 O3 control. AD-MSCs grew and proliferated on all the scaffolds tested, as well as secreted abundant extracellular matrix, when osteogenic differentiation was appropriately stimulated. 45S5 and S53P4 induced enhanced expression of COL2A1, COL10A1, COL5A1 collagen subunits, and pro-osteogenic genes BMP2 and BMP4. The concomitant downregulation of BMP3 was also detected. Our findings show that FRC-BG can support the vascularization of the implant and the formation of abundant connective tissue in vivo. Specifically, BG 45S5 and BG S53P4 are suited to evoke the osteogenic potential of host mesenchymal stromal cells. In conclusion, FRC-BG implant demonstrated material-induced ossification both in vitro and in vivo.

• Klíčová slova
• bioactive glass, bioactivity, biomaterial-induced ossification, cranial implant, fiber-reinforced composite, osteogenesis,
• MeSH
• biokompatibilní materiály aplikace a dávkování   MeSH
• lebka zranění   metabolismus   MeSH
• lidé středního věku MeSH
• lidé MeSH
• osteogeneze účinky léků   MeSH
• protézy a implantáty * MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• kazuistiky MeSH
• práce podpořená grantem MeSH
• Názvy látek
• biokompatibilní materiály MeSH

A firm connection of the bone-implant-fixation system is of utmost importance for patients with cranial defects. In order to improve the connection reliability, the current research focuses on finding the optimal fixation method, as well as selection of the implant manufacturing methods and the used materials. For the latter, implementation of bioactive materials such as hydroxyapatite or other calcium phosphates has also been considered in the literature. The aim of this study was to investigate the effect of gradual osseointegration on the biomechanical performance of cranial Ti6Al4V implants with a deposited HA coating as the osseointegration agent. This effect was assessed by two different computational approaches using finite element method (FEM) modeling. The values of key input parameters necessary for FEM were obtained from experimental plasma spray deposition of HA layers onto Ti6Al4V samples. Immediately upon implantation, the HA layer at the bone-implant contact area brought only a slight decrease in the values of von Mises stress in the implant and the micro-screws when compared to a non-coated counterpart; importantly, this was without any negative trade-off in other important characteristics. The major benefit of the HA coatings was manifested upon the modeled osseointegration: the results of both approaches confirmed a significant reduction of investigated parameters such as the total implant displacements (reduced from 0.050 mm to 0.012 mm and 0.002 mm while using Approach I and II, respectively) and stresses (reduced from 52 MPa to 10 MPa and 1 MPa) in the implanted components in comparison to non-coated variant. This is a very promising result for potential use of thermally sprayed HA coatings for cranial implants.

• MeSH
• analýza metodou konečných prvků MeSH
• biokompatibilní potahované materiály chemie   farmakologie   MeSH
• fosforečnany vápenaté chemie   farmakologie   MeSH
• hydroxyapatit chemie   farmakologie   MeSH
• kostní náhrady chemie   farmakologie   MeSH
• lebka diagnostické zobrazování   účinky léků   patologie   MeSH
• lidé MeSH
• osteointegrace účinky léků   fyziologie   MeSH
• protézy a implantáty MeSH
• slitiny chemie   farmakologie   MeSH
• testování materiálů MeSH
• titan chemie   farmakologie   MeSH
• zubní implantáty * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• biokompatibilní potahované materiály MeSH
• fosforečnany vápenaté MeSH
• hydroxyapatit MeSH
• kostní náhrady MeSH
• slitiny MeSH
• titan MeSH
• titanium alloy (TiAl6V4) MeSH Prohlížeč
• zubní implantáty * MeSH

Titanium dental implants are a multibillion dollar market in the United States alone. The growth of a bacterial biofilm on a dental implant can cause gingivitis, implant loss, and expensive subsequent care. Herein, we demonstrate the efficient eradication of dental biofilm on titanium dental implants via swarming magnetic microrobots based on ferromagnetic (Fe3O4) and photoactive (BiVO4) materials through polyethylenimine micelles. The ferromagnetic component serves as a propulsion force using a transversal rotating magnetic field while BiVO4 is the photoactive generator of reactive oxygen species to eradicate the biofilm colonies. Such photoactive magnetically powered, precisely navigated microrobots are able to destroy biofilm colonies on titanium implants, demonstrating their use in precision medicine.

• Klíčová slova
• bacterial biofilm, ferromagnetic material, micromotors, photoactive material, polymer micelles,
• MeSH
• biofilmy MeSH
• magnetické jevy MeSH
• povrchové vlastnosti MeSH
• titan * MeSH
• zubní implantáty * MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• titan * MeSH
• zubní implantáty * MeSH

STATEMENT OF PROBLEM: Fatigue failure of implant components is a common clinical problem. Plasma nitriding, an in situ surface-strengthening method, may improve fatigue properties of dental implants. PURPOSE: The purpose of this in vitro study was to evaluate the effect of plasma nitriding on the fatigue behavior of implant systems. MATERIAL AND METHODS: The preload and friction coefficient of plasma nitrided abutment screws, as well as settlement of the implant-abutment interface, were measured. Then, the reverse torque values and pullout force were evaluated after cyclic loading. Finally, the fatigue properties of the implant system were investigated with static fracture and dynamic fatigue life tests, and the morphology of the fracture on the surface of the implant system was observed. RESULTS: The plasma nitriding treatment reduced the friction coefficient; increased the preload, settlement value, reverse torque values, pullout force, and static fracture load; and prolonged fatigue life. Furthermore, abutment screws with plasma nitriding treatment showed a different fatigue fracture mode. CONCLUSIONS: Plasma nitriding improved mechanical performance and may be a suitable way to optimize the fatigue behavior of dental implants.

• MeSH
• analýza zatížení zubů metody   MeSH
• design pilíře zubního implantátu MeSH
• podpěry zubní MeSH
• testování materiálů MeSH
• točivý moment MeSH
• tření MeSH
• zubní implantáty * MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• zubní implantáty * MeSH

Complicated geometry in combination with surface treatment strongly deteriorates fatigue resistance of metallic dental implants. Mechanical properties of pure Ti grade 2, usually used for dental implant production, were shown to be significantly improved due to intensive grain refinement via Conform SPD. The increase of the tensile strength properties was accompanied by a significant increase in the fatigue resistance and fatigue endurance limit. However, the SLA treatment usually used for the implants' surface roughening, resulted in the fatigue properties and endurance limit decrease, while this effect was more pronounced for the ultrafine-grained comparing to the coarse-grained material when tested under tensile-tensile loading mode. The testing of the implants is usually provided under the bending mode. Even though different testing condition for the conventional specimens tests and implants testing was adopted, a numerical study revealed their comparable fatigue properties. The fatigue limit determined for the implants was 105% higher than the one for coarse-grained and only by 4 % lower than the one for ultrafine-grained Ti grade 2. Based on the obtained results, conventional specimens testing can be used for the prediction of the fatigue limit of the implants.

• Klíčová slova
• Dental implant, Fatigue, SLA treatment, Ti grade 2, Ultrafine-grained,
• MeSH
• pevnost v tahu MeSH
• povrchové vlastnosti MeSH
• testování materiálů MeSH
• titan * MeSH
• zubní implantáty * MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• titan * MeSH
• zubní implantáty * MeSH

The presence of artificial implants complicates the delivery of proton therapy due to inaccurate characterization of both the implant and the surrounding tissues. In this work, we describe a method to characterize implant and human tissue mimicking materials in terms of relative stopping power (RSP) using a novel proton counting detector. Each proton is tracked by directly measuring the deposited energy along the proton track using a fast, pixelated spectral detector AdvaPIX-TPX3 (TPX3). We considered three scenarios to characterize the RSPs. First, in-air measurements were made in the presence of metal rods (Al, Ti and CoCr) and bone. Then, measurements of energy perturbations in the presence of metal implants and bone in an anthropomorphic phantom were performed. Finally, sampling of cumulative stopping power (CSP) of the phantom were made at different locations of the anthropomorphic phantom. CSP and RSP information were extracted from energy spectra at each beam path. To quantify the RSP of metal rods we used the shift in the most probable energy (MPE) of CSP from the reference CSP without a rod. Overall, the RSPs were determined as 1.48, 2.06, 3.08, and 5.53 from in-air measurements; 1.44, 1.97, 2.98, and 5.44 from in-phantom measurements, for bone, Al, Ti and CoCr, respectively. Additionally, we sampled CSP for multiple paths of the anthropomorphic phantom ranging from 18.63 to 25.23 cm deriving RSP of soft tissues and bones in agreement within 1.6% of TOPAS simulations. Using minimum error of these multiple CSP, optimal mass densities were derived for soft tissue and bone and they are within 1% of vendor-provided nominal densities. The preliminary data obtained indicates the proposed novel method can be used for the validation of material and density maps, required by proton Monte Carlo Dose calculation, provided by competing multi-energy computed tomography and metal artifact reduction techniques.

• MeSH
• fantomy radiodiagnostické * MeSH
• lidé MeSH
• metoda Monte Carlo * MeSH
• protézy a implantáty * MeSH
• protonová terapie přístrojové vybavení   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

OBJECTIVE: Breast augmentation is one of the most commonly performed plastic surgery procedures worldwide. Because of the quality of the implant material, implant rupture may first occur about 10 years after implantation. Ruptured breast implants caused by competitive sport events are rare but should be considered in women athletes as a potential risk factor. The authors report a noteworthy case of this kind. DESIGN: Literature overview and case report. SETTING: Department of Plastic and Obstetrics and Gynaecology 1st faculty of Charls University, Bulovka hospital, Prague. METHODS: Evaluation of the literature and an observational study. CONCLUSION: Breast implant ruptures are generally at high risk in competitive contact sports. We do not recommend the use of breast implants in women competing in contact sports such as boxing.

• Klíčová slova
• boxing, breast implant, rupture, trauma,
• MeSH
• implantace prsní náhrady MeSH
• lidé MeSH
• mamoplastika * MeSH
• prsní implantáty * MeSH
• selhání protézy * MeSH
• silikonové gely MeSH
• spontánní ruptura MeSH
• Check Tag
• lidé MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• kazuistiky MeSH
• přehledy MeSH
• Názvy látek
• silikonové gely MeSH

When choosing between metal implants of different materials the surgeon mainly needs to balance the pros and cons of steel and titanium. Economic constraints often do not permit both to be kept in stock and it is necessary to decide beforehand which to choose. The arguments for the use of the "preferred metal" vary. The present paper elucidates the practical aspects based on the complex scientific background that has identified the differences between the two metals in their mechanical, electrochemical, biological and application behavior. The data presented here are intended to help the surgeon when he is confronted with different and often complex clinical situations and problems. The following is an overview of different aspects to help with selection of the proper material for the clinical application. The first part concerns mechanical aspects the second part the biological aspects. Both aspects are discussed with the practical application in mind. Nonmetallic implant materials have seen an increasing interest in the recent past. Plastic materials needed improvement to achieve good strength and avoid creep with loss of e.g. compression and minimizing leakage of chemicals.

• MeSH
• biomechanika MeSH
• lidé MeSH
• ocel MeSH
• ortopedické výkony přístrojové vybavení   MeSH
• protézy a implantáty * MeSH
• testování materiálů MeSH
• titan MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• ocel MeSH
• titan MeSH