Microstructural characterization of titanium dental implants by electron microscopy and mechanical tests; Caracterizacao microestrutural de implantes dentarios de titanio por microscopia eletronica e ensaios mecanicos

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Helfenstein, B.; Muniz, N.O.; Dedavid, B.A., E-mail: bruhelfenstein@hotmail.co [Pontificia Univ. Catolica do Rio Grande do Sul (FE/PUC/RS), Porto Alegre, RS (Brazil). Fac. de Engenharia; Gehrke, S.A. [Universidade Federal de Santa Maria (FE/UFSM), RS (Brazil). Fac. de Engenharia; Vargas, A.L.M. [Parque Tecnologico da PUCRS (TECNOPUC/GEPSI), Porto Alegre, RS (Brazil). Grupo de Estudos de Propriedades de Superficies e Interfaces

2010-07-01

Mini screw types for titanium implants, with differentiated design, were tested for traction and torsion for behavior analysis of the shape relative to the requirements of ASTM F136. All implants showed mechanical tensile strength above by the standard requirement, being that 83.3% of them broke above the doughnut, in support of the prosthesis. Distinct morphologies in ruptured by mechanical tests, were obtained. However, both fracture surfaces showed fragile comportments. Metallographic tests, x-ray diffraction (XRD) and microhardness were used for microstructural characterization of material, before and after heat treatment. The presences of {beta} phase in screw surface after quenching treatment proves that the thermal treatment can contribute for mechanical resistance in surface implants. (author)

A rationale method for evaluating unscrewing torque values of prosthetic screws in dental implants

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Felipe Miguel Saliba

2011-02-01

Full Text Available OBJECTIVES: Previous studies that evaluated the torque needed for removing dental implant screws have not considered the manner of transfer of the occlusal loads in clinical settings. Instead, the torque used for removal was applied directly to the screw, and most of them omitted the possibility that the hexagon could limit the action of the occlusal load in the loosening of the screws. The present study proposes a method for evaluating the screw removal torque in an anti-rotational device independent way, creating an unscrewing load transfer to the entire assembly, not only to the screw. MATERIAL AND METHODS: Twenty hexagonal abutments without the hexagon in their bases were fixed with a screw to 20 dental implants. They were divided into two groups: Group 1 used titanium screws and Group 2 used titanium screws covered with a solid lubricant. A torque of 32 Ncm was applied to the screw and then a custom-made wrench was used for rotating the abutment counterclockwise, to loosen the screw. A digital torque meter recorded the torque required to loosen the abutment. RESULTS: There was a significant difference between the means of Group 1 (38.62±6.43 Ncm and Group 2 (48.47±5.04 Ncm, with p=0.001. CONCLUSION: This methodology was effective in comparing unscrewing torque values of the implant-abutment junction even with a limited sample size. It confirmed a previously shown significant difference between two types of screws.

[Effectiveness of U-shape titanium screw-rod fixation system with bone autografting for lumbar spondylolysis of young adults].

Science.gov (United States)

Pu, Xiaobing; Yang, Shuangshi; Cao, Haiquan; Jing, Xingquan; Yin, Jun

2014-03-01

To investigate the effectiveness of U-shape titanium screw-rod fixation system with bone autografting for lumbar spondylolysis of young adults. Between January 2008 and December 2011, 32 patients with lumbar spondylolysis underwent U-shape titanium screw-rod fixation system with bone autografting. All patients were male with an average age of 22 years (range, 19-32 years). The disease duration ranged from 3 to 24 months (mean, 14 months). L3 was involved in spondylolysis in 2 cases, L4 in 10 cases, and L5 in 20 cases. The preoperative visual analogue scale (VAS) and Oswestry disability index (ODI) scores were 8.0 +/- 1.1 and 75.3 +/- 11.2, respectively. The operation time was 80-120 minutes (mean, 85 minutes), and the blood loss was 150-250 mL (mean, 210 mL). Primary healing of incision was obtained in all patients without complications of infection and nerve symptom. Thirty-two patients were followed up 12-24 months (mean, 14 months). Low back pain was significantly alleviated after operation. The VAS and ODI scores at 3 months after operation were 1.0 +/- 0.5 and 17.6 +/- 3.4, respectively, showing significant differences when compared with preoperative ones (t = 30.523, P = 0.000; t = 45.312, P = 0.000). X-ray films and CT showed bone fusion in the area of isthmus defects, with the bone fusion time of 6-12 months (mean, 9 months). During follow-up, no secondary lumbar spondyloly, adjacent segment degeneration, or loosening or breaking of internal fixator was found. The U-shape titanium screw-rod fixation system with bone autografting is a reliable treatment for lumbar spondylolysis of young adults because of a high fusion rate, minimal invasive, and maximum retention of lumbar range of motion.

Removal torque of nail interlocking screws is related to screw proximity to the fracture and screw breakage.

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White, Alexander A; Kubacki, Meghan R; Samona, Jason; Telehowski, Paul; Atkinson, Patrick J

2016-06-01

Studies have shown that titanium implants can be challenging to explant due to the material's excellent biocompatibility and resulting osseointegration. Clinically, titanium alloy nail interlocking screws may require removal to dynamize a construct or revise the nail due to nonunion, infection, pain, or periprosthetic fracture. This study was designed to determine what variables influence the removal torque for titanium alloy interlocking screws. An intramedullary nail with four interlocking screws was used to stabilize a 1-cm segmental femoral defect in a canine model for 16 weeks. The animals were observed to be active following a several-day recovery after surgery. In six animals, the femora and implanted nail/screws were first tested to failure in torsion to simulate periprosthetic fracture of an implant after which the screws were then removed. In four additional animals, the screws were removed without mechanical testing. Both intraoperative insertional and extraction torques were recorded for all screws. Mechanical testing to failure broke 10/24 screws. On average, the intact screws required 70% of the insertional torque during removal while broken screws only required 16% of the insertional torque (p torque than the outboard distal screw (p torque was ∼80°. The peak axial load did not significantly correlate with the torque required to remove the screws. On average, the removal torque was lower than at the time of insertion, and less torque was required to remove broken screws and screws remote to the fracture. However, broken screws will require additional time to retrieve the remaining screw fragment. This study suggests that broken screws and screws in prematurely active patients will require less torque to remove. © IMechE 2016.

MicroCT Analysis of Micro-Nano Titanium Implant Surface on the Osseointegration.

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Ban, Jaesam; Kang, Seongsoo; Kim, Jihyun; Lee, Kwangmin; Hyunpil, Lim; Vang, Mongsook; Yang, Hongso; Oh, Gyejeong; Kim, Hyunseung; Hwang, Gabwoon; Jung, Yongho; Lee, Kyungku; Park, Sangwon; Yunl, Kwidug

2015-01-01

This study was to investigate the effects of micro-nano titanium implant surface on the osseointegration. A total of 36 screw-shaped implants were used. The implant surfaces were classified into 3 groups (n = 12): machined surface (M group), nanosurface which is nanotube formation on the machined surface (MA group) and nano-micro surface which is nanotube formation on the RBM surface (RA group). Anodic oxidation was performed at a 20 V for 10 min with 1 M H3PO4 and 1.5 wt% HF solutions. The implants were installed on the humerus on 6 beagles. After 4 and 12 weeks, the morphometric analysis with micro CT (skyscan 1172, SKYSCAN, Antwerpen, Belgium) was done. The data were statistically analyzed with two-way ANOVA. Bone mineral density and bone volume were significantly increased depending on time. RA group showed the highest bone mineral density and bone volume at 4 weeks and 12 weeks significantly. It indicated that nano-micro titanium implant surface showed faster and more mature osseointegration.

Magnetic resonance imaging susceptibility artifacts in the cervical vertebrae and spinal cord related to monocortical screw-polymethylmethacrylate implants in canine cadavers.

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Jones, Brian G; Fosgate, Geoffrey T; Green, Eric M; Habing, Amy M; Hettlich, Bianca F

2017-04-01

OBJECTIVE To characterize and compare MRI susceptibility artifacts related to titanium and stainless steel monocortical screws in the cervical vertebrae and spinal cord of canine cadavers. SAMPLE 12 canine cadavers. PROCEDURES Cervical vertebrae (C4 and C5) were surgically stabilized with titanium or stainless steel monocortical screws and polymethylmethacrylate. Routine T1-weighted, T2-weighted, and short tau inversion recovery sequences were performed at 3.0 T. Magnetic susceptibility artifacts in 20 regions of interest (ROIs) across 4 contiguous vertebrae (C3 through C6) were scored by use of an established scoring system. RESULTS Artifact scores for stainless steel screws were significantly greater than scores for titanium screws at 18 of 20 ROIs. Artifact scores for titanium screws were significantly higher for spinal cord ROIs within the implanted vertebrae. Artifact scores for stainless steel screws at C3 were significantly less than at the other 3 cervical vertebrae. CONCLUSIONS AND CLINICAL RELEVANCE Evaluation of routine MRI sequences obtained at 3.0 T revealed that susceptibility artifacts related to titanium monocortical screws were considered mild and should not hinder the overall clinical assessment of the cervical vertebrae and spinal cord. However, mild focal artifacts may obscure small portions of the spinal cord or intervertebral discs immediately adjacent to titanium screws. Severe artifacts related to stainless steel screws were more likely to result in routine MRI sequences being nondiagnostic; however, artifacts may be mitigated by implant positioning.

Implant-supported titanium prostheses following augmentation procedures: a clinical report.

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Knabe, C; Hoffmeister, B

2003-03-01

This report describes a novel technique for fabricating retrievable implant-supported titanium (Ti) prostheses in patients requiring a comprehensive treatment plan involving the combined efforts of maxillofacial surgery and implant prosthodontics. Following bone graft reconstructive surgery and implant placement prosthetic treatment was initiated by inserting ITI-Octa abutments. An impression was made, and a framework was fabricated by fusing Ti-cast frameworks to prefabricated titanium copings by laser-welding. This was followed by veneering or fabrication of a removable denture with Ti metal re-enforcement. Favourable clinical results have been achieved using these screw-retained Ti implant-supported restorations for patients treated with reconstructive bone graft-surgery, with clinical observation periods ranging from three to four years. The present observations suggest that these screw-retained implant-supported Ti prostheses may be a meaningful contribution to implant prosthodontics, facilitating retrievable restorations of optimum biocompatibility, good marginal precision and with a good esthetic result. However, controlled clinical studies are needed to establish the long-term serviceability of these Ti restorations.

A comparison of fit of CNC-milled titanium and zirconia frameworks to implants.

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Abduo, Jaafar; Lyons, Karl; Waddell, Neil; Bennani, Vincent; Swain, Michael

2012-05-01

Computer numeric controlled (CNC) milling was proven to be predictable method to fabricate accurately fitting implant titanium frameworks. However, no data are available regarding the fit of CNC-milled implant zirconia frameworks. To compare the precision of fit of implant frameworks milled from titanium and zirconia and relate it to peri-implant strain development after framework fixation. A partially edentulous epoxy resin models received two Branemark implants in the areas of the lower left second premolar and second molar. From this model, 10 identical frameworks were fabricated by mean of CNC milling. Half of them were made from titanium and the other half from zirconia. Strain gauges were mounted close to the implants to qualitatively and quantitatively assess strain development as a result of framework fitting. In addition, the fit of the framework implant interface was measured using an optical microscope, when only one screw was tightened (passive fit) and when all screws were tightened (vertical fit). The data was statistically analyzed using the Mann-Whitney test. All frameworks produced measurable amounts of peri-implant strain. The zirconia frameworks produced significantly less strain than titanium. Combining the qualitative and quantitative information indicates that the implants were under vertical displacement rather than horizontal. The vertical fit was similar for zirconia (3.7 µm) and titanium (3.6 µm) frameworks; however, the zirconia frameworks exhibited a significantly finer passive fit (5.5 µm) than titanium frameworks (13.6 µm). CNC milling produced zirconia and titanium frameworks with high accuracy. The difference between the two materials in terms of fit is expected to be of minimal clinical significance. The strain developed around the implants was more related to the framework fit rather than framework material. © 2011 Wiley Periodicals, Inc.

Cannabis sativa smoke inhalation decreases bone filling around titanium implants: a histomorphometric study in rats.

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Nogueira-Filho, Getulio da R; Cadide, Tiago; Rosa, Bruno T; Neiva, Tiago G; Tunes, Roberto; Peruzzo, Daiane; Nociti, Francisco Humberto; César-Neto, João B

2008-12-01

Although the harmful effect of tobacco smoking on titanium implants has been documented, no studies have investigated the effects of cannabis sativa (marijuana) smoking. Thus, this study investigated whether marijuana smoke influences bone healing around titanium implants. Thirty Wistar rats were used. After anesthesia, the tibiae surface was exposed and 1 screw-shaped titanium implant was placed bilaterally. The animals were randomly assigned to one of the following groups: control (n = 15) and marijuana smoke inhalation (MSI) 8 min/d (n = 15). Urine samples were obtained to detect the presence of tetra-hidro-cannabinoid. After 60 days, the animals were killed. The degree of bone-to-implant contact and the bone area within the limits of the threads of the implant were measured in the cortical (zone A) and cancellous bone (zone B). Tetra-hidro-cannabinoid in urine was positive only for the rats of MSI group. Intergroup analysis did not indicate differences in zone A-cortical bone (P > 0.01), however, a negative effect of marijuana smoke (MSI group) was observed in zone B-cancellous bone for bone-to-implant contact and bone area (Student's t test, P smoke on bone healing may represent a new concern for implant success/failure.

[Fracture of implant abutment screws and removal of a remaining screw piece

NARCIS (Netherlands)

Broeke, S.M. van den; Baat, C. de

2008-01-01

Fracture of the implant abutment screws is a complication which can render an implant useless. The prevalence of abutment screw fracture does not exceed 2.5% after 10 years. Causes are loosening of implant abutment screw, too few, too short or too narrow implants, implants not inserted perpendicular

Fracture Resistance and Mode of Failure of Ceramic versus Titanium Implant Abutments and Single Implant-Supported Restorations.

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Sghaireen, Mohd G

2015-06-01

The material of choice for implant-supported restorations is affected by esthetic requirements and type of abutment. This study compares the fracture resistance of different types of implant abutments and implant-supported restorations and their mode of failure. Forty-five Oraltronics Pitt-Easy implants (Oraltronics Dental Implant Technology GmbH, Bremen, Germany) (4 mm diameter, 10 mm length) were embedded in clear autopolymerizing acrylic resin. The implants were randomly divided into three groups, A, B and C, of 15 implants each. In group A, titanium abutments and metal-ceramic crowns were used. In group B, zirconia ceramic abutments and In-Ceram Alumina crowns were used. In group C, zirconia ceramic abutments and IPS Empress Esthetic crowns were used. Specimens were tested to failure by applying load at 130° from horizontal plane using an Instron Universal Testing Machine. Subsequently, the mode of failure of each specimen was identified. Fracture resistance was significantly different between groups (p Empress crowns supported by zirconia abutments had the lowest fracture loads (p = .000). Fracture modes of metal-ceramic crowns supported by titanium abutments included screw fracture and screw bending. Fracture of both crown and abutment was the dominant mode of failure of In-Ceram/IPS Empress crowns supported by zirconia abutments. Metal-ceramic crowns supported by titanium abutments were more resistant to fracture than In-Ceram crowns supported by zirconia abutments, which in turn were more resistant to fracture than IPS Empress crowns supported by zirconia abutments. In addition, failure modes of restorations supported by zirconia abutments were more catastrophic than those for restorations supported by titanium abutments. © 2013 Wiley Periodicals, Inc.

In vivo evaluation of immediately loaded stainless steel and titanium orthodontic screws in a growing bone.

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Kerstin Gritsch

Full Text Available The present work intends to evaluate the use of immediate loaded orthodontic screws in a growing model, and to study the specific bone response. Thirty-two screws (half of stainless steel and half of titanium were inserted in the alveolar bone of 8 growing pigs. The devices were immediately loaded with a 100 g orthodontic force. Two loading periods were assessed: 4 and 12 weeks. Both systems of screws were clinically assessed. Histological observations and histomorphometric analysis evaluated the percent of "bone-to-implant contact" and static and dynamic bone parameters in the vicinity of the devices (test zone and in a bone area located 1.5 cm posterior to the devices (control zone. Both systems exhibit similar responses for the survival rate; 87.5% and 81.3% for stainless steel and titanium respectively (p = 0.64; 4-week period, and 62.5% and 50.0% for stainless steel and titanium respectively (p = 0.09; 12-week period. No significant differences between the devices were found regarding the percent of "bone-to-implant contact" (p = 0.1 or the static and dynamic bone parameters. However, the 5% threshold of "bone-to-implant contact" was obtained after 4 weeks with the stainless steel devices, leading to increased survival rate values. Bone in the vicinity of the miniscrew implants showed evidence of a significant increase in bone trabecular thickness when compared to bone in the control zone (p = 0.05. In our study, it is likely that increased trabecular thickness is a way for low density bone to respond to the stress induced by loading.

In vivo evaluation of immediately loaded stainless steel and titanium orthodontic screws in a growing bone.

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Gritsch, Kerstin; Laroche, Norbert; Bonnet, Jeanne-Marie; Exbrayat, Patrick; Morgon, Laurent; Rabilloud, Muriel; Grosgogeat, Brigitte

2013-01-01

The present work intends to evaluate the use of immediate loaded orthodontic screws in a growing model, and to study the specific bone response. Thirty-two screws (half of stainless steel and half of titanium) were inserted in the alveolar bone of 8 growing pigs. The devices were immediately loaded with a 100 g orthodontic force. Two loading periods were assessed: 4 and 12 weeks. Both systems of screws were clinically assessed. Histological observations and histomorphometric analysis evaluated the percent of "bone-to-implant contact" and static and dynamic bone parameters in the vicinity of the devices (test zone) and in a bone area located 1.5 cm posterior to the devices (control zone). Both systems exhibit similar responses for the survival rate; 87.5% and 81.3% for stainless steel and titanium respectively (p = 0.64; 4-week period), and 62.5% and 50.0% for stainless steel and titanium respectively (p = 0.09; 12-week period). No significant differences between the devices were found regarding the percent of "bone-to-implant contact" (p = 0.1) or the static and dynamic bone parameters. However, the 5% threshold of "bone-to-implant contact" was obtained after 4 weeks with the stainless steel devices, leading to increased survival rate values. Bone in the vicinity of the miniscrew implants showed evidence of a significant increase in bone trabecular thickness when compared to bone in the control zone (p = 0.05). In our study, it is likely that increased trabecular thickness is a way for low density bone to respond to the stress induced by loading.

Printing of Titanium implant prototype

International Nuclear Information System (INIS)

Wiria, Florencia Edith; Shyan, John Yong Ming; Lim, Poon Nian; Wen, Francis Goh Chung; Yeo, Jin Fei; Cao, Tong

2010-01-01

Dental implant plays an important role as a conduit of force and stress to flow from the tooth to the related bone. In the load sharing between an implant and its related bone, the amount of stress carried by each of them directly related to their stiffness or modulus. Hence, it is a crucial issue for the implant to have matching mechanical properties, in particular modulus, between the implant and its related bone. Titanium is a metallic material that has good biocompatibility and corrosion resistance. Whilst the modulus of the bulk material is still higher than that of bone, it is the lowest among all other commonly used metallic implant materials, such as stainless steel or cobalt alloy. Hence it is potential to further reduce the modulus of pure Titanium by engineering its processing method to obtain porous structure. In this project, porous Titanium implant prototype is fabricated using 3-dimensional printing. This technique allows the flexibility of design customization, which is beneficial for implant fabrication as tailoring of implant size and shape helps to ensure the implant would fit nicely to the patient. The fabricated Titanium prototype had a modulus of 4.8-13.2 GPa, which is in the range of natural bone modulus. The compressive strength achieved was between 167 to 455 MPa. Subsequent cell culture study indicated that the porous Titanium prototype had good biocompatibility and is suitable for bone cell attachment and proliferation.

THE INFLUENCE OF SCREW TYPE, ALLOY AND CYLINDER POSITION ON THE MARGINAL FIT OF IMPLANT FRAMEWORKS BEFORE AND AFTER LASER WELDING

OpenAIRE

Castilio, Daniela; Pedreira, Ana Paula Ribeiro do Vale; Rossetti, Paulo Henrique Orlato; Rossetti, Leylha Maria Nunes; Bonachela, Wellington Cardoso

2006-01-01

Misfit at the abutment-prosthetic cylinder interface can cause loss of preload, leading to loosening or fracture of gold and titanium screws. OBJECTIVES: To evaluate the influence of screw type, alloy, and cylinder position on marginal fit of implant frameworks before and after laser welding. METHODS: After Estheticone-like abutments were screwed to the implants, thirty plastic prosthetic cylinders were mounted and waxed-up to fifteen cylindrical bars. Each specimen had three interconnected p...

Electropolished Titanium Implants with a Mirror-Like Surface Support Osseointegration and Bone Remodelling

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Cecilia Larsson Wexell

2016-01-01

Full Text Available This work characterises the ultrastructural composition of the interfacial tissue adjacent to electropolished, commercially pure titanium implants with and without subsequent anodisation, and it investigates whether a smooth electropolished surface can support bone formation in a manner similar to surfaces with a considerably thicker surface oxide layer. Screw-shaped implants were electropolished to remove all topographical remnants of the machining process, resulting in a thin spontaneously formed surface oxide layer and a smooth surface. Half of the implants were subsequently anodically oxidised to develop a thickened surface oxide layer and increased surface roughness. Despite substantial differences in the surface physicochemical properties, the microarchitecture and the composition of the newly formed bone were similar for both implant surfaces after 12 weeks of healing in rabbit tibia. A close spatial relationship was observed between osteocyte canaliculi and both implant surfaces. On the ultrastructural level, the merely electropolished surface showed the various stages of bone formation, for example, matrix deposition and mineralisation, entrapment of osteoblasts within the mineralised matrix, and their morphological transformation into osteocytes. The results demonstrate that titanium implants with a mirror-like surface and a thin, spontaneously formed oxide layer are able to support bone formation and remodelling.

In vivo bioactivity of titanium and fluorinated apatite coatings for orthopaedic implants: a vibrational study

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Taddei, Paola; Tinti, Anna; Reggiani, Matteo; Monti, Patrizia; Fagnano, Concezio

2003-06-01

The bone integration of implants is a complex process which depends on chemical composition and surface morphology. To accelerate osteointegration, metal implants are coated with porous metal or apatites which have been reported to increase mineralisation, improving prosthesis fixation. To study the influence of composition and morphology on the in vivo bioactivity, titanium screws coated by Plasma Flame Spraying (PFS) with titanium or fluorinated apatite (K690) were implanted in sheep tibia and femur for 10 weeks and studied by micro-Raman and IR spectroscopy. The same techniques, together with thermogravimetry, were used for characterising the pre-coating K690 powder. Contrary to the manufacturer report, the K690 pre-coating revealed to be composed of a partially fluorinated apatite containing impurities of Ca(OH) 2 and CaCO 3. By effect of PFS, the impurities were decomposed and the crystallinity degree of the coating was found to decrease. The vibrational spectra recorded on the implanted screws revealed the presence of newly formed bone; for the K690-coated screws at least, a high level of osteointegration was evidenced.

The influence of screw type, alloy and cylinder position on the marginal fit of implant frameworks before and after laser welding.

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Castilio, Daniela; Pedreira, Ana Paula Ribeiro do Vale; Rossetti, Paulo Henrique Orlato; Rossetti, Leylha Maria Nunes; Bonachela, Wellington Cardoso

2006-04-01

Misfit at the abutment-prosthetic cylinder interface can cause loss of preload, leading to loosening or fracture of gold and titanium screws. To evaluate the influence of screw type, alloy, and cylinder position on marginal fit of implant frameworks before and after laser welding. After Estheticone-like abutments were screwed to the implants, thirty plastic prosthetic cylinders were mounted and waxed-up to fifteen cylindrical bars. Each specimen had three interconnected prosthetic components. Five specimens were one-piece cast in titanium and five in cobalt-chromium alloy. On each specimen, tests were conducted with hexagonal titanium and slotted gold screws separately, performing a total of thirty tested screws. Measurements at the interfaces were performed using an optical microscope with 5mm accuracy. After sectioning, specimens were laser welded and new measurements were obtained. Data were submitted to a four-way ANOVA and Tukey's multiple comparisons test (alpha=0.05). Slotted and hexagonal screws did not present significant differences regarding to the fit of cylinders cast in titanium, either in one-piece casting framework or after laser welding. When slotted and hexagonal screws were tested on the cobalt-chromium specimens, statistically significant differences were found for the one-piece casting condition, with the slotted screws presenting better fit (24.13 microm) than the hexagonal screws (27.93 microm). Besides, no statistically significant differences were found after laser welding. 1) The use of different metal alloys do exert influence on the marginal fit, 2) The slotted and hexagonal screws play the exclusive role of fixing the prosthesis, and did not improve the fit of cylinders, and 3) cylinder position did not affect marginal fit values.

Does surface anodisation of titanium implants change osseointegration and make their extraction from bone any easier?

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Langhoff, J D; Mayer, J; Faber, L; Kaestner, S B; Guibert, G; Zlinszky, K; Auer, J A; von Rechenberg, B

2008-01-01

Titanium implants have a tendency for high bone-implant bonding, and, in comparison to stainless steel implants are more difficult to remove. The current study was carried out to evaluate, i) the release strength of three selected anodized titanium surfaces with increased nanohardness and low roughness, and ii) bone-implant bonding in vivo. These modified surfaces were intended to give improved anchorage while facilitating easier removal of temporary implants. The new surfaces were referenced to a stainless steel implant and a standard titanium implant surface (TiMAX). In a sheep limb model, healing period was 3 months. Bone-implant bonding was evaluated either biomechanically or histologically. The new surface anodized screws demonstrated similar or slightly higher bone-implant-contact (BIC) and torque release forces than the titanium reference. The BIC of the stainless steel implants was significant lower than two of the anodized surfaces (p = 0.04), but differences between stainless steel and all titanium implants in torque release forces were not significant (p = 0.06). The new anodized titanium surfaces showed good bone-implant bonding despite a smooth surface and increased nanohardness. However, they failed to facilitate implant removal at 3 months.

A simplified method to reduce prosthetic misfit for a screw-retained, implant-supported complete denture using a luting technique and laser welding.

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Longoni, Salvatore; Sartori, Matteo; Davide, Roberto

2004-06-01

An important aim of implant-supported prostheses is to achieve a passive fit of the framework with the abutments to limit the amount of stress transfer to the bone-implant interface. An efficient and standardized technique is proposed. A definitive screw-retained, implant-supported complete denture was fabricated for an immediately loaded provisional screw-retained implant-supported complete denture. Precise fit was achieved by the use of industrial titanium components and the passivity, by an intraoral luting sequence and laser welding.

Effects of Screw Configuration on the Preload Force of Implant-Abutment Screws.

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Zipprich, Holger; Rathe, Florian; Pinz, Sören; Schlotmann, Luca; Lauer, Hans-Christoph; Ratka, Christoph

The aim of this study was to investigate the effects of tightening torque, screw head angle, and thread number on the preload force of abutment screws. The test specimens consisted of three self-manufactured components (ie, a thread sleeve serving as an implant analog, an abutment analog, and an abutment screw). The abutment screws were fabricated with metric M1.6 external threads. The thread number varied between one and seven threads. The screw head angles were produced in eight varying angles (30 to 180 degrees). A sensor unit simultaneously measured the preload force of the screw and the torsion moment inside the screw shank. The tightening of the screw with the torque wrench was performed in five steps (15 to 35 Ncm). The torque wrench was calibrated before each step. Only the tightening torque and screw head angle affected the resulting preload force of the implant-abutment connection. The thread number had no effect. There was an approximately linear correlation between tightening torque and preload force. The tightening torque and screw head angle were the only study parameters that affected the resulting preload force of the abutment screw. The results obtained from this experiment are valid only for a single torque condition. Further investigations are needed that analyze other parameters that affect preload force. Once these parameters are known, it will add value for a strong, but detachable connection between the implant and abutment. Short implants and flat-to-flat connections especially will benefit significantly from this knowledge.

In vitro investigation of marginal accuracy of implant-supported screw-retained partial dentures.

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Koke, U; Wolf, A; Lenz, P; Gilde, H

2004-05-01

Mismatch occurring during the fabrication of implant-supported dentures may induce stress to the peri-implant bone. The purpose of this study was to investigate the influence of two different alloys and the fabrication method on the marginal accuracy of cast partial dentures. Two laboratory implants were bonded into an aluminium block so that the distance between their longitudinal axes was 21 mm. Frameworks designed for screw-retained partial dentures were cast either with pure titanium (rematitan) or with a CoCr-alloy (remanium CD). Two groups of 10 frameworks were cast in a single piece. The first group was made of pure titanium, and the second group of a CoCr-alloy (remanium CD). A third group of 10 was cast in two pieces and then laser-welded onto a soldering model. This latter group was also made of the CoCr-alloy. All the frameworks were screwed to the original model with defined torque. Using light microscopy, marginal accuracy was determined by measuring vertical gaps at eight defined points around each implant. Titanium frameworks cast in a single piece demonstrated mean vertical gaps of 40 microm (s.d. = 11 microm) compared with 72 microm (s.d. = 40 microm) for CoCr-frameworks. These differences were not significant (U-test, P = 0.124) because of a considerable variation of the values for CoCr-frameworks (minimum: 8 microm and maximum: 216 microm). However, frameworks cast in two pieces and mated with a laser showed significantly better accuracy in comparison with the other experimental groups (mean: 17 microm +/- 6; P laser welding. Manufacturing the framework pieces separately and then welding them together provides the best marginal fit.

Mini-screw implant or transpalatal arch-mediated anchorage reinforcement during canine retraction: a randomized clinical trial.

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Sharma, Mohit; Sharma, Vineet; Khanna, Bharat

2012-06-01

To compare mesial movement of upper first molars during maxillary canine retraction using a pre-adjusted edgewise appliance provided by anchorage reinforcement and a transpalatal arch or mini-screw implant. Randomized clinical trial. Department of Orthodontics and Dentofacial Orthopedics, Armed Forces Medical College, Pune, India. From a cohort of subjects requiring the extraction of both upper first premolars and pre-adjusted edgewise appliances to correct their malocclusion, a total of 30 were randomly allocated to receive two different forms of anchorage reinforcement: group A--receiving mini-screw implant and group B--receiving a transpalatal arch Group A subjects received titanium mini-screw implants placed at the start of treatment between the maxillary second premolar and maxillary first molar. Maxillary second premolars were secured to the mini-screw implants using of 0.010-inch stainless steel ligature wire. Group B subjects received a custom-made transpalatal arch which was soldered to maxillary first molar bands. Active canine retraction was initiated in both groups on placement of a 0.019×0.025-inch stainless steel archwire using nickel titanium closed coil springs. Mesial movement of the upper first molars as measured on pre- (T1) and post-treatment (T2) lateral skull radiographs. The results showed that in group A the mean mesial movement of the first molars between T1 and T2 was 0.0 mm (SD 0.02; P = 0.90), whereas in Group B there was a mean forward movement of the first maolars of 2.48 mm (SD 0.71; Pimplants placed prior to levelling and aligning were able to provide absolute anchorage during maxillary canine retraction, in contrast to a transpalatal arch.

Effect of zirconium nitride physical vapor deposition coating on preosteoblast cell adhesion and proliferation onto titanium screws.

Science.gov (United States)

Rizzi, Manuela; Gatti, Giorgio; Migliario, Mario; Marchese, Leonardo; Rocchetti, Vincenzo; Renò, Filippo

2014-11-01

Titanium has long been used to produce dental implants. Problems related to its manufacturing, casting, welding, and ceramic application for dental prostheses still limit its use, which highlights the need for technologic improvements. The aim of this in vitro study was to evaluate the biologic performance of titanium dental implants coated with zirconium nitride in a murine preosteoblast cellular model. The purpose of this study was to evaluate the chemical and morphologic characteristics of titanium implants coated with zirconium nitride by means of physical vapor deposition. Chemical and morphologic characterizations were performed by scanning electron microscopy and energy dispersive x-ray spectroscopy, and the bioactivity of the implants was evaluated by cell-counting experiments. Scanning electron microscopy and energy dispersive x-ray spectroscopy analysis found that physical vapor deposition was effective in covering titanium surfaces with zirconium nitride. Murine MC-3T3 preosteoblasts were seeded onto titanium-coated and zirconium nitride-coated screws to evaluate their adhesion and proliferation. These experiments found a significantly higher number of cells adhering and spreading onto zirconium nitride-coated surfaces (Pzirconium nitride surfaces were completely covered with MC-3T3 cells. Analysis of these data indicates that the proposed zirconium nitride coating of titanium implants could make the surface of the titanium more bioactive than uncoated titanium surfaces. Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Segmental vs non-segmental thoracic pedicle screws constructs in adolescent idiopathic scoliosis: is there any implant alloy effect?

Science.gov (United States)

Di Silvestre, Mario; Bakaloudis, Georgeous; Ruosi, Carlo; Pipola, Valerio; Colella, Gianluca; Greggi, Tiziana; Ruffilli, Alberto; Vommaro, Francesco

2017-10-01

The aim of this study is to understand how many anchor sites are necessary to obtain maximum posterior correction of idiopathic scoliotic curve and if the alloy of instrumentation, stainless steel or titanium, may have a role in the percent of scoliosis correction. We reviewed 143 consecutive patients, affected by AIS (Lenke 1-2), who underwent a posterior spinal fusion with pedicle screw-only instrumentation between 2002 and 2005. According to the implant density and alloy used we divided the cohort in four groups. All 143 patients were reviewed at an average follow-up of 7, 2 years, the overall final main thoracic curve correction averaged 61.4%, whereas the implant density within the major curve averaged 71%. A significant correlation was observed between final% MT correction and preoperative MT flexibility and implant density. When stainless steel instrumentation is used non-segmental pedicle screw constructs seem to be equally effective as segmental instrumentations in obtaining satisfactory results in patients with main thoracic AIS. When the implant alloy used is titanium one, an implant density of ≥60% should be guaranteed to achieve similar results.

In vivo degradation of a new concept of magnesium-based rivet-screws in the minipig mandibular bone

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Schaller, Benoit [Department of Cranio-Maxillofacial Surgery, Inselspital, Bern University Hospital and University of Bern, CH-3010 Bern (Switzerland); National Dental Centre Singapore, 168938 (Singapore); Saulacic, Nikola [Department of Cranio-Maxillofacial Surgery, Inselspital, Bern University Hospital and University of Bern, CH-3010 Bern (Switzerland); Beck, Stefan, E-mail: SBECK2@its.jnj.com [Synthes Biomaterials, Eimattstr. 3, CH-4436 Oberdorf (Switzerland); Imwinkelried, Thomas [RMS Foundation, Bischmattstr. 12, CH-2544 Bettlach (Switzerland); Goh, Bee Tin [National Dental Centre Singapore, 168938 (Singapore); Nakahara, Ken [Department of Cranio-Maxillofacial Surgery, Inselspital, Bern University Hospital and University of Bern, CH-3010 Bern (Switzerland); Hofstetter, Willy [Department of Clinical Research, University of Bern, CH-3010 Bern (Switzerland); Iizuka, Tateyuki [Department of Cranio-Maxillofacial Surgery, Inselspital, Bern University Hospital and University of Bern, CH-3010 Bern (Switzerland)

2016-12-01

Self-tapping of magnesium screws in hard bone may be a challenge due to the limited torsional strength of magnesium alloys in comparison with titanium. To avoid screw failure upon implantation, the new concept of a rivet-screw was applied to a WE43 magnesium alloy. Hollow cylinders with threads on the outside were expanded inside drill holes of minipig mandibles. During the expansion with a hexagonal mandrel, the threads engaged the surrounding bone and the inside of the screw transformed into a hexagonal screw drive to allow further screwing in or out of the implant. The in vivo degradation of the magnesium implants and the performance of the used coating were studied in a human standard-sized animal model. Four magnesium alloy rivet-screws were implanted in each mandible of 12 minipigs. Six animals received the plasmaelectrolytically coated magnesium alloy implants; another six received the uncoated magnesium alloy rivet-screws. Two further animals received one titanium rivet-screw each as control. In vivo radiologic examination was performed at one, four, and eight weeks. Euthanasia was performed for one group of seven animals (three animals with coated, three with uncoated magnesium alloy implants and one with titanium implant) at 12 weeks and for the remaining seven animals at 24 weeks. After euthanasia, micro-computed tomography and histological examination with histomorphometry were performed. Significantly less void formation as well as higher bone volume density (BV/TV) and bone-implant contact area (BIC) were measured around the coated implants compared to the uncoated ones. The surface coating was effective in delaying degradation despite plastic deformation. The results showed potential for further development of magnesium hollow coated screws for bone fixation. - Highlights: • A new concept of rivet screws as an alternative to classical screws is presented • The rivet screw concept was tested in vivo in a mini-pig pilot study • Un-coated and

In vivo degradation of a new concept of magnesium-based rivet-screws in the minipig mandibular bone

International Nuclear Information System (INIS)

Schaller, Benoit; Saulacic, Nikola; Beck, Stefan; Imwinkelried, Thomas; Goh, Bee Tin; Nakahara, Ken; Hofstetter, Willy; Iizuka, Tateyuki

2016-01-01

Self-tapping of magnesium screws in hard bone may be a challenge due to the limited torsional strength of magnesium alloys in comparison with titanium. To avoid screw failure upon implantation, the new concept of a rivet-screw was applied to a WE43 magnesium alloy. Hollow cylinders with threads on the outside were expanded inside drill holes of minipig mandibles. During the expansion with a hexagonal mandrel, the threads engaged the surrounding bone and the inside of the screw transformed into a hexagonal screw drive to allow further screwing in or out of the implant. The in vivo degradation of the magnesium implants and the performance of the used coating were studied in a human standard-sized animal model. Four magnesium alloy rivet-screws were implanted in each mandible of 12 minipigs. Six animals received the plasmaelectrolytically coated magnesium alloy implants; another six received the uncoated magnesium alloy rivet-screws. Two further animals received one titanium rivet-screw each as control. In vivo radiologic examination was performed at one, four, and eight weeks. Euthanasia was performed for one group of seven animals (three animals with coated, three with uncoated magnesium alloy implants and one with titanium implant) at 12 weeks and for the remaining seven animals at 24 weeks. After euthanasia, micro-computed tomography and histological examination with histomorphometry were performed. Significantly less void formation as well as higher bone volume density (BV/TV) and bone-implant contact area (BIC) were measured around the coated implants compared to the uncoated ones. The surface coating was effective in delaying degradation despite plastic deformation. The results showed potential for further development of magnesium hollow coated screws for bone fixation. - Highlights: • A new concept of rivet screws as an alternative to classical screws is presented • The rivet screw concept was tested in vivo in a mini-pig pilot study • Un-coated and

The Improvement of Bone-Tendon Fixation by Porous Titanium Interference Screw: A Rabbit Animal Model.

Science.gov (United States)

Tsai, Pei-I; Chen, Chih-Yu; Huang, Shu-Wei; Yang, Kuo-Yi; Lin, Tzu-Hung; Chen, San-Yuan; Sun, Jui-Sheng

2018-05-04

The interference screw is a widely used fixation device in the anterior cruciate ligament (ACL) reconstruction surgeries. Despite the generally satisfactory results, problems of using interference screws were reported. By using additive manufacturing (AM) technology, we developed an innovative titanium alloy (Ti 6 Al 4 V) interference screw with rough surface and inter-connected porous structure designs to improve the bone-tendon fixation. An innovative Ti 6 Al 4 V interference screws were manufactured by AM technology. In vitro mechanical tests were performed to validate its mechanical properties. Twenty-seven New Zealand white rabbits were randomly divided into control and AM screw groups for biomechanical analyses and histological analysis at 4, 8 and 12 weeks postoperatively; while micro-CT analysis was performed at 12 weeks postoperatively. The biomechanical tests showed that the ultimate failure load in the AM interference screw group was significantly higher than that in the control group at all tested periods. These results were also compatible with the findings of micro-CT and histological analyses. In micro-CT analysis, the bone-screw gap was larger in the control group; while for the additive manufactured screw, the screw and bone growth was in close contact. In histological study, the bone-screw gaps were wider in the control group and were almost invisible in the AM screw group. The innovative AM interference screws with surface roughness and inter-connected porous architectures demonstrated better bone-tendon-implant integration, and resulted in stronger biomechanical characteristics when compared to traditional screws. These advantages can be transferred to future interference screw designs to improve their clinical performance. The AM interference screw could improve graft fixation and eventually result in better biomechanical performance of the bone-tendon-screw construct. The innovative AM interference screws can be transferred to future

Effect of abutment screw length and cyclic loading on removal torque in external and internal hex implants.

Science.gov (United States)

Mohammed, Hnd Hadi; Lee, Jin-Han; Bae, Ji-Myung; Cho, Hye-Won

2016-02-01

The purpose of this study was to evaluate the effects of abutment screw length and cyclic loading on the removal torque (RTV) in external hex (EH) and internal hex (IH) implants. Forty screw-retained single crowns were connected to external and internal hex implants. The prepared titanium abutment screws were classified into 8 groups based on the number of threads (n = 5 per group): EH 12.5, 6.5, 3.5, 2.5 and IH 6.5, 5, 3.5, 2.5 threads. The abutment screws were tightened with 20 Ncm torque twice with 10-minute intervals. After 5 minutes, the initial RTVs of the abutment screws were measured with a digital torque gauge (MGT12). A customized jig was constructed to apply a load along the implant long axis at the central fossa of the maxillary first molar. The post-loading RTVs were measured after 16,000 cycles of mechanical loading with 50 N at a 1-Hz frequency. Statistical analysis included one-way analysis of variance and paired t-tests. The post-loading RTVs were significantly lower than the initial RTVs in the EH 2.5 thread and IH 2.5 thread groups (P<.05). The initial RTVs exhibited no significant differences among the 8 groups, whereas the post-loading RTVs of the EH 6.5 and EH 3.5 thread groups were higher than those of the IH 3.5 thread group (P<.05). Within the limitations of this study, the external hex implants with short screw lengths were more advantageous than internal hex implants with short screw lengths in torque maintenance after cyclic loading.

Tightening techniques for the retaining screws of universal abutment

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Alexandre Wittcinski REGALIN

Full Text Available Abstract Purpose This study evaluated the torque maintenance of universal abutment retaining screws using different tightening techniques, and coated or uncoated screws. Material and method The screws were tightened to implants as following: Control – 32 Ncm torque; H20 – holding 32 Ncm torque for 20 s; R – 32 Ncm torque, repeated after 10 min (retorque; and H20+R – combining the two tightening techniques. Titanium and coated screws were also evaluated. Result Statistical analysis showed higher maintained torque for titanium screws (p<0.001. The H20+R technique showed the highest maintained torque (p=0.003, but the H20 technique’s maintained torque was similar. Conclusion Titanium screws associating the two tightening techniques can improve maintained torque.

Perturbation effects of the carbon fiber-PEEK screws on radiotherapy dose distribution.

Science.gov (United States)

Nevelsky, Alexander; Borzov, Egor; Daniel, Shahar; Bar-Deroma, Raquel

2017-03-01

Radiation therapy, in conjunction with surgical implant fixation, is a common combined treatment in cases of bone metastases. However, metal implants generally used in orthopedic implants perturb radiation dose distributions. Carbon-Fiber Reinforced Polyetheretherketone (CFR-PEEK) material has been recently introduced for production of intramedullary nails and plates. The purpose of this work was to investigate the perturbation effects of the new CFR-PEEK screws on radiotherapy dose distributions and to evaluate these effects in comparison with traditional titanium screws. The investigation was performed by means of Monte Carlo (MC) simulations for a 6 MV photon beam. The project consisted of two main stages. First, a comparison of measured and MC calculated doses was performed to verify the validity of the MC simulation results for different materials. For this purpose, stainless steel, titanium, and CFR-PEEK plates of various thicknesses were used for attenuation and backscatter measurements in a solid water phantom. For the same setup, MC dose calculations were performed. Next, MC dose calculations for titanium, CFR-PEEK screws, and CFR-PEEK screws with ultrathin titanium coating were performed. For the plates, the results of our MC calculations for all materials were found to be in good agreement with the measurements. This indicates that the MC model can be used for calculation of dose perturbation effects caused by the screws. For the CFR-PEEK screws, the maximum dose perturbation was less than 5%, compared to more than 30% perturbation for the titanium screws. Ultrathin titanium coating had a negligible effect on the dose distribution. CFR-PEEK implants have good prospects for use in radiotherapy because of minimal dose alteration and the potential for more accurate treatment planning. This could favorably influence treatment efficiency and decrease possible over- and underdose of adjacent tissues. The use of such implants has potential clinical advantages

Stability of prototype two-piece zirconia and titanium implants after artificial aging: an in vitro pilot study.

Science.gov (United States)

Kohal, Ralf-Joachim; Finke, Hans Christian; Klaus, Gerold

2009-12-01

Zirconia oral implants are a new topic in implant dentistry. So far, no data are available on the biomechanical behavior of two-piece zirconia implants. Therefore, the purpose of this pilot investigation was to test in vitro the fracture strength of two-piece cylindrical zirconia implants after aging in a chewing simulator. This laboratory in vitro investigation comprised three different treatment groups. Each group consisted of 16 specimens. In group 1, two-piece zirconia implants were restored with zirconia crowns (zirconia copings veneered with Triceram; Esprident, Ispringen, Germany), and in group 2 zirconia implants received Empress 2 single crowns (Ivoclar Vivadent AG, Schaan, Liechtenstein). The implants, including the abutments, in the two zirconia groups were identical. In group 3, similar titanium implants were reconstructed with porcelain-fused-to-metal crowns. Eight samples of each group were submitted to artificial aging with a long-term load test in the artificial mouth (chewing simulator). Subsequently, all not artificially aged samples and all artificially aged samples that survived the long-term loading of each group were submitted to a fracture strength test in a universal testing machine. For the pairwise comparisons in the different test groups with or without artificial loading and between the different groups at a given artificial loading condition, the Wilcoxon rank-sum test for independent samples was used. The significance level was set at 5%. One sample of group 1 (veneer fracture), none of group 2, and six samples of group 3 (implant abutment screw fractures) failed while exposed to the artificial mouth. The values for the fracture strength after artificial loading with 1.2 million cycles for group 1 were between 45 and 377 N (mean: 275.7 N), in group 2 between 240 and 314 N (mean: 280.7 N), and in the titanium group between 45 and 582 N (mean: 165.7 N). The fracture strength results without artificial load for group 1 amounted to between

Loosening torque of Universal Abutment screws after cyclic loading: influence of tightening technique and screw coating.

Science.gov (United States)

Bacchi, Atais; Regalin, Alexandre; Bhering, Claudia Lopes Brilhante; Alessandretti, Rodrigo; Spazzin, Aloisio Oro

2015-10-01

The purpose of this study was to evaluate the influence of tightening technique and the screw coating on the loosening torque of screws used for Universal Abutment fixation after cyclic loading. Forty implants (Titamax Ti Cortical, HE, Neodent) (n=10) were submerged in acrylic resin and four tightening techniques for Universal Abutment fixation were evaluated: A - torque with 32 Ncm (control); B - torque with 32 Ncm holding the torque meter for 20 seconds; C - torque with 32 Ncm and retorque after 10 minutes; D - torque (32 Ncm) holding the torque meter for 20 seconds and retorque after 10 minutes as initially. Samples were divided into subgroups according to the screw used: conventional titanium screw or diamond like carbon-coated (DLC) screw. Metallic crowns were fabricated for each abutment. Samples were submitted to cyclic loading at 10(6) cycles and 130 N of force. Data were analyzed by two-way ANOVA and Tukey's test (5%). The tightening technique did not show significant influence on the loosening torque of screws (P=.509). Conventional titanium screws showed significant higher loosening torque values than DLC (P=.000). The use of conventional titanium screw is more important than the tightening techniques employed in this study to provide long-term stability to Universal Abutment screws.

Evaluation of MR issues for the latest standard brands of orthopedic metal implants: Plates and screws

Energy Technology Data Exchange (ETDEWEB)

Zou, Yue-fen, E-mail: zou_yf@163.com [Department of Radiology, The First Affiliated Hospital of Nanjing Medical University, No. 300 Guangzhou Road, Nanjing (China); Chu, Bin, E-mail: 18262636700@163.com [Department of Radiology, The First Affiliated Hospital of Nanjing Medical University, No. 300 Guangzhou Road, Nanjing (China); Wang, Chuan-bing, E-mail: wangchuanb_csr@163.com [Department of Radiology, The First Affiliated Hospital of Nanjing Medical University, No. 300 Guangzhou Road, Nanjing (China); Hu, Zhi-yi, E-mail: huzhiyi@medmail.com.cn [Department of Spine Surgery, The First Affiliated Hospital of Nanjing Medical University, No. 300 Guangzhou Road, Nanjing (China)

2015-03-15

Highlights: •Although previous studies have indicated that most of the orthopedic implants are compatible in MR imaging system especially for titanium alloy, there are still concerns about the safety of patients with stainless steel implants, who were refused to a MR scan in most cases in our country. •In this study, it was verified that both titanium alloy and stainless steel materials (plates and screws) cause a weak force and low MRI-related heating at a 1.5-T or less, which do not pose an additional hazard or risk to patients. In addition, we also had explored the influence of different sequences and parameters on size of metallic artifacts to obtain optimized pulse sequences with appropriate parameters for reducing artifacts, which would be convenient and useful in clinical work. -- Abstract: Purpose: The study was performed to evaluate magnetic resonance (MR) issues for the latest standard brands of plates and screws used in orthopedic surgery at a 1.5-T MR system, including the safety and metallic artifacts. Methods: The plates and screws (made of titanium alloy and stainless steel materials, according to the latest standard brands) were assessed for displacement in degrees, MRI-related heating and artifacts at a 1.5-T MR system. The displacement in degrees of the plates and screws was evaluated on an angel-measurement instrument at the entrance of the MR scanner. The MRI-related heating was assessed on a swine leg fixed with a plate by using a “worst-case” pulse sequence. A rectangular water phantom was designed to evaluate metallic artifacts of a screw on different sequences (T1/T2-weighted FSE, STIR, T2-FSE fat saturation, GRE, DWI) and then artifacts were evaluated on T2-weighted FSE sequence by modifying the scanning parameters including field of view (FOV), echo train length (ETL) and bandwidth to identify the influence of parameters on metallic artifacts. 15 volunteers with internal vertebral fixation (titanium alloy materials) were scanned

Evaluation of MR issues for the latest standard brands of orthopedic metal implants: Plates and screws

International Nuclear Information System (INIS)

Zou, Yue-fen; Chu, Bin; Wang, Chuan-bing; Hu, Zhi-yi

2015-01-01

Highlights: •Although previous studies have indicated that most of the orthopedic implants are compatible in MR imaging system especially for titanium alloy, there are still concerns about the safety of patients with stainless steel implants, who were refused to a MR scan in most cases in our country. •In this study, it was verified that both titanium alloy and stainless steel materials (plates and screws) cause a weak force and low MRI-related heating at a 1.5-T or less, which do not pose an additional hazard or risk to patients. In addition, we also had explored the influence of different sequences and parameters on size of metallic artifacts to obtain optimized pulse sequences with appropriate parameters for reducing artifacts, which would be convenient and useful in clinical work. -- Abstract: Purpose: The study was performed to evaluate magnetic resonance (MR) issues for the latest standard brands of plates and screws used in orthopedic surgery at a 1.5-T MR system, including the safety and metallic artifacts. Methods: The plates and screws (made of titanium alloy and stainless steel materials, according to the latest standard brands) were assessed for displacement in degrees, MRI-related heating and artifacts at a 1.5-T MR system. The displacement in degrees of the plates and screws was evaluated on an angel-measurement instrument at the entrance of the MR scanner. The MRI-related heating was assessed on a swine leg fixed with a plate by using a “worst-case” pulse sequence. A rectangular water phantom was designed to evaluate metallic artifacts of a screw on different sequences (T1/T2-weighted FSE, STIR, T2-FSE fat saturation, GRE, DWI) and then artifacts were evaluated on T2-weighted FSE sequence by modifying the scanning parameters including field of view (FOV), echo train length (ETL) and bandwidth to identify the influence of parameters on metallic artifacts. 15 volunteers with internal vertebral fixation (titanium alloy materials) were scanned

Laser-treated stainless steel mini-screw implants: 3D surface roughness, bone-implant contact, and fracture resistance analysis.

Science.gov (United States)

Kang, He-Kyong; Chu, Tien-Min; Dechow, Paul; Stewart, Kelton; Kyung, Hee-Moon; Liu, Sean Shih-Yao

2016-04-01

This study investigated the biomechanical properties and bone-implant intersurface response of machined and laser surface-treated stainless steel (SS) mini-screw implants (MSIs). Forty-eight 1.3mm in diameter and 6mm long SS MSIs were divided into two groups. The control (machined surface) group received no surface treatment; the laser-treated group received Nd-YAG laser surface treatment. Half in each group was used for examining surface roughness (Sa and Sq), surface texture, and facture resistance. The remaining MSIs were placed in the maxilla of six skeletally mature male beagle dogs in a randomized split-mouth design. A pair with the same surface treatment was placed on the same side and immediately loaded with 200 g nickel-titanium coil springs for 8 weeks. After killing, the bone-implant contact (BIC) for each MSI was calculated using micro computed tomography. Analysis of variance model and two-sample t test were used for statistical analysis with a significance level of P titanium alloy MSIs. © The Author 2015. Published by Oxford University Press on behalf of the European Orthodontic Society. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Nanostructured titanium-based materials for medical implants: Modeling and development

DEFF Research Database (Denmark)

Mishnaevsky, Leon; Levashov, Evgeny; Valiev, Ruslan Z.

2014-01-01

Nanostructuring of titanium-based implantable devices can provide them with superior mechanical properties and enhanced biocompatibity. An overview of advanced fabrication technologies of nanostructured, high strength, biocompatible Ti and shape memory Ni-Ti alloy for medical implants is given. C...

Osteogenesis and Morphology of the Peri-Implant Bone Facing Dental Implants

Directory of Open Access Journals (Sweden)

Marco Franchi

2004-01-01

Full Text Available This study investigated the influence of different implant surfaces on peri-implant osteogenesis and implant face morphology of peri-implant tissues during the early (2 weeks and complete healing period (3 months. Thirty endosseous titanium implants (conic screws with differently treated surfaces (smooth titanium = SS, titanium plasma sprayed = TPS, sand-blasted zirconium oxide = Zr-SLA were implanted in femur and tibiae diaphyses of two mongrel sheep. Histological sections of the implants and surrounding tissues obtained by sawing and grinding techniques were observed under light microscopy (LM. The peri-implant tissues of other samples were mechanically detached from the corresponding implants to be processed for SEM observation. Two weeks after implantation, we observed osteogenesis (new bone trabeculae around all implant surfaces only where a gap was present at the host bone-metal interface. No evident bone deposition was detectable where threads of the screws were in direct contact with the compact host bone. Distance osteogenesis predominated in SS implants, while around rough surfaces (TPS and Zr-SLA, both distance and contact osteogenesis were present. At SEM analysis 2 weeks after implantation, the implant face of SS peri-implant tissue showed few, thin, newly formed, bone trabeculae immersed in large, loose, marrow tissue with blood vessels. Around the TPS screws, the implant face of the peri-implant tissue was rather irregular because of the rougher metal surface. Zr-SLA screws showed more numerous, newly formed bone trabeculae crossing marrow spaces and also needle-like crystals in bone nodules indicating an active mineralising process. After 3 months, all the screws appeared osseointegrated, being almost completely covered by a compact, mature, newly formed bone. However, some marrow spaces rich in blood vessels and undifferentiated cells were in contact with the metal surface. By SEM analysis, the implant face of the peri-implant

Effectiveness of screw surface coating on the stability of zirconia abutments after cyclic loading.

Science.gov (United States)

Basílio, Mariana de Almeida; Butignon, Luis Eduardo; Arioli Filho, João Neudenir

2012-01-01

Different surface treatments have been developed in attempts to prevent the loosening of abutment screws. The aim of the current study was to compare the effectiveness of titanium alloy screws with tungsten-doped diamond-like carbon (W-DLC) coating and uncoated screws in providing stability to zirconia (ZrO2) ceramic abutments after cyclic loading. Twenty prefabricated ZrO2 ceramic abutments on their respective external-hex implants were divided into two groups of equal size according to the type of screw used: uncoated titanium alloy screw (Ti) or titanium alloy screw with W-DLC coating (W-DLC/Ti). The removal torque value (preload) of the abutment screw was measured before and after loading. Cyclic loading between 11 and 211 N was applied at an angle of 30 degrees to the long axis of the implants at a frequency of 15 Hz. A target of 0.5 X 106 cycles was defined. Group means were calculated and compared using analysis of variance and the F test (α = .05). Before cyclic loading, the preload for Ti screws was significantly higher than that for W-DLC/Ti screws (P = .021). After cyclic loading, there was no significant difference between them (P = .499). Under the studied conditions, it can be concluded that, after cyclic loading, both abutment screws presented a significant reduction in the mean retained preload and similar effectiveness in maintaining preload.

Comparison of 3D displacements of screw-retained zirconia implant crowns into implants with different internal connections with respect to screw tightening.

Science.gov (United States)

Rebeeah, Hanadi A; Yilmaz, Burak; Seidt, Jeremy D; McGlumphy, Edwin; Clelland, Nancy; Brantley, William

2018-01-01

Internal conical implant-abutment connections without horizontal platforms may lead to crown displacement during screw tightening and torque application. This displacement may affect the proximal contacts and occlusion of the definitive prosthesis. The purpose of this in vitro study was to evaluate the displacement of custom screw-retained zirconia single crowns into a recently introduced internal conical seal implant-abutment connection in 3D during hand and torque driver screw tightening. Stereolithic acrylic resin models were printed using computed tomography data from a patient missing the maxillary right central incisor. Two different internal connection implant systems (both ∼11.5 mm) were placed in the edentulous site in each model using a surgical guide. Five screw-retained single zirconia computer-aided design and computer-aided manufacturing (CAD-CAM) crowns were fabricated for each system. A pair of high-resolution digital cameras was used to record the relationship of the crown to the model. The crowns were tightened according to the manufacturers' specifications using a torque driver, and the cameras recorded their relative position again. Three-dimensional image correlation was used to measure and compare crown positions, first hand tightened and then torque driven. The displacement test was repeated 3 times for each crown. Commercial image correlation software was used to extract the data and compare the amount of displacement vertically, mesiodistally, and buccolingually. Repeated-measures ANOVA calculated the relative displacements for all 5 specimens for each implant for both crown screw hand tightening and after applied torque. A Student t test with Bonferroni correction was used for pairwise comparison of interest to determine statistical differences between the 2 implants (α=.05). The mean vertical displacements were statistically higher than the mean displacements in the mesiodistal and buccolingual directions for both implants

Comparison of migration behavior between single and dual lag screw implants for intertrochanteric fracture fixation

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Katonis Pavlos G

2009-05-01

Full Text Available Abstract Background Lag screw cut-out failure following fixation of unstable intertrochanteric fractures in osteoporotic bone remains an unsolved challenge. This study tested if resistance to cut-out failure can be improved by using a dual lag screw implant in place of a single lag screw implant. Migration behavior and cut-out resistance of a single and a dual lag screw implant were comparatively evaluated in surrogate specimens using an established laboratory model of hip screw cut-out failure. Methods Five dual lag screw implants (Endovis, Citieffe and five single lag screw implants (DHS, Synthes were tested in the Hip Implant Performance Simulator (HIPS of the Legacy Biomechanics Laboratory. This model simulated osteoporotic bone, an unstable fracture, and biaxial rocking motion representative of hip loading during normal gait. All constructs were loaded up to 20,000 cycles of 1.45 kN peak magnitude under biaxial rocking motion. The migration kinematics was continuously monitored with 6-degrees of freedom motion tracking system and the number of cycles to implant cut-out was recorded. Results The dual lag screw implant exhibited significantly less migration and sustained more loading cycles in comparison to the DHS single lag screw. All DHS constructs failed before 20,000 cycles, on average at 6,638 ± 2,837 cycles either by cut-out or permanent screw bending. At failure, DHS constructs exhibited 10.8 ± 2.3° varus collapse and 15.5 ± 9.5° rotation around the lag screw axis. Four out of five dual screws constructs sustained 20,000 loading cycles. One dual screw specimens sustained cut-out by medial migration of the distal screw after 10,054 cycles. At test end, varus collapse and neck rotation in dual screws implants advanced to 3.7 ± 1.7° and 1.6 ± 1.0°, respectively. Conclusion The single and double lag screw implants demonstrated a significantly different migration resistance in surrogate specimens under gait loading simulation with

A comparison of laser-welded titanium and conventional cast frameworks supported by implants in the partially edentulous jaw: a 3-year prospective multicenter study.

Science.gov (United States)

Jemt, T; Henry, P; Lindén, B; Naert, I; Weber, H; Bergström, C

2000-01-01

The purpose of this prospective multicenter study was to evaluate and compare the clinical performance of laser-welded titanium fixed partial implant-supported prostheses with conventional cast frameworks. Forty-two partially edentulous patients were provided with Brånemark system implants and arranged into 2 groups. Group A was provided with a conventional cast framework with porcelain veneers in one side of the jaw and a laser-welded titanium framework with low-fusing porcelain on the other side. The patients in group B had an old implant prosthesis replaced by a titanium framework prosthesis. The patients were followed for 3 years after prosthesis placement. Clinical and radiographic data were collected and analyzed. Only one implant was lost, and all prostheses were still in function after 3 years. The 2 framework designs showed similar clinical performance with few clinical complications. Only one abutment screw (1%) and 9 porcelain tooth units (5%) fractured. Four prostheses experienced loose gold screws (6%). In group A, marginal bone loss was similar for both designs of prostheses, with a mean of 1.0 mm and 0.3 mm in the maxilla and mandible, respectively. No bone loss was observed on average in group B. No significant relationship (P > 0.05) was observed between marginal bone loss and placement of prosthesis margin or prosthesis design. The use of laser-welded titanium frameworks seems to present similar clinical performance to conventional cast frameworks in partial implant situations after 3 years.

Clinical experiences of implant-supported prostheses with laser-welded titanium frameworks in the partially edentulous jaw: a 5-year follow-up study.

Science.gov (United States)

Ortorp, A; Jemt, T

1999-01-01

Titanium frameworks have been used in the endentulous implant patient for the last 10 years. However, knowledge of titanium frameworks for the partially dentate patient is limited. To report the 5-year clinical performance of implant-supported prostheses with laser-welded titanium frameworks in the partially edentulous jaw. A consecutive group of 383 partially edentulous patients were, on a routine basis, provided with fixed partial prostheses supported by Brånemark implants in the mandible or maxilla. Besides conventional frameworks in cast gold alloy, 58 patients were provided with titanium frameworks with three different veneering techniques, and clinical and radiographic 5-year data were collected for this group. The overall cumulative survival rate was 95.6% for titanium-framework prostheses and 93.6% for implants. Average bone loss during the follow-up period was 0.4 mm. The most common complications were minor veneering fractures. Loose and fractured implant screw components were fewer than 2%. An observation was that patients on medications for cardiovascular problems may lose more implants than others (p laser-welded titanium frameworks was similar to that reported for conventional cast frames in partially edentulous jaws. Low-fusing porcelain veneers also showed clinical performance comparable to that reported for conventional porcelain-fused-to-metal techniques.

Hollow Abutment Screw Design for Easy Retrieval in Case of Screw Fracture in Dental Implant System

OpenAIRE

Sim, Bo Kyun; Kim, Bongju; Kim, Min Jeong; Jeong, Guk Hyun; Ju, Kyung Won; Shin, Yoo Jin; Kim, Man Yong; Lee, Jong-Ho

2017-01-01

The prosthetic component of dental implant is attached on the abutment which is connected to the fixture with an abutment screw. The abutment screw fracture is not frequent; however, the retrieval of the fractured screw is not easy, and it poses complications. A retrieval kit was developed which utilizes screw removal drills to make a hole on the fractured screw that provides an engaging drill to unscrew it. To minimize this process, the abutment screw is modified with a prefabricated access ...

Micro-computerised tomography optimisation for the measurement of bone mineral density around titanium dental implants

International Nuclear Information System (INIS)

Park, C.; Swain, M.; Duncan, W.

2010-01-01

Titanium dental implants (screws) are commonly used to replace missing teeth by forming a biological union with bone ('osseointegration'). Micro-computerised tomography (μCT) may be useful for measuring bone mineral density around dental implants. Major issues arise because of various artefacts that occur with polychromatic X-rays associated bench type instruments that may compromise interpretation of the observations. In this study various approaches to minimise artefacts such as; beam hardening, filtering and edge effects are explored with a homogeneous polymeric material, Teflon, with and without an implant present. The implications of the limitations of using such polychromatic μCT systems to quantify bone mineral density adjacent to the implant are discussed. (author)

Influence of abutment screw preload on stress distribution in marginal bone.

Science.gov (United States)

Khraisat, Ameen

2012-01-01

Changes in an implant assembly after abutment connection might possibly cause deformation in the implant/abutment joint and even in the marginal bone. The aim of this study was to evaluate the influence of abutment screw preload through the implant collar on marginal bone stress without external load application. Models of three implant parts made of titanium (implant, abutment, and abutment screw) and cortical bone were built and positioned with computer-aided design software. Meshing and generation of boundary conditions, loads, and interactions were performed. Each part was meshed independently. The sole load applied to the model was a torque of 32 Ncm on the abutment screw about its axis of rotation. The implant collar was deformed axially after the screw was tightened (3 μm). This deformation resulted in 60 MPa of stress in the marginal bone. Moreover, pressure on the marginal bone in a radial direction was observed. It can be concluded that, without any external load application, abutment screw preload exerts stresses on the implant collar and the marginal bone. These findings should help guide the development of new implant/abutment joint designs that exert less stress on the marginal bone.

Bone reactions adjacent to titanium implants subjected to static load of different duration. A study in the dog (III)

DEFF Research Database (Denmark)

Gotfredsen, K; Berglundh, T; Lindhe, J

2001-01-01

The aim of the present experiment was to study the effect of a long-standing lateral static load on the peri-implant bone. Three beagle dogs were used. The mandibular premolars were extracted and 12 weeks later 3 titanium implants (ITI(R) Dental Implant System) were installed in each quadrant....... Crowns were fitted to all implants 12 weeks after the installation procedure. The anterior and central crowns were fused and connected to the posterior crown by an expansion screw. In the right side of the mandible, the expansion screws were activated every 2 weeks during a 46-week period. During...... the last 10 weeks of this period, an expansion force similar to that of the right side was applied in the left. The animals were sacrificed and block biopsies of each implant site harvested and prepared for histological analysis. Sites subjected to 10 weeks or 46 weeks of lateral load had a similar (i...

Complications with computer-aided designed/computer-assisted manufactured titanium and soldered gold bars for mandibular implant-overdentures: short-term observations.

Science.gov (United States)

Katsoulis, Joannis; Wälchli, Julia; Kobel, Simone; Gholami, Hadi; Mericske-Stern, Regina

2015-01-01

Implant-overdentures supported by rigid bars provide stability in the edentulous atrophic mandible. However, fractures of solder joints and matrices, and loosening of screws and matrices were observed with soldered gold bars (G-bars). Computer-aided designed/computer-assisted manufactured (CAD/CAM) titanium bars (Ti-bars) may reduce technical complications due to enhanced material quality. To compare prosthetic-technical maintenance service of mandibular implant-overdentures supported by CAD/CAM Ti-bar and soldered G-bar. Edentulous patients were consecutively admitted for implant-prosthodontic treatment with a maxillary complete denture and a mandibular implant-overdenture connected to a rigid G-bar or Ti-bar. Maintenance service and problems with the implant-retention device complex and the prosthesis were recorded during minimally 3-4 years. Annual peri-implant crestal bone level changes (ΔBIC) were radiographically assessed. Data of 213 edentulous patients (mean age 68 ± 10 years), who had received a total of 477 tapered implants, were available. Ti-bar and G-bar comprised 101 and 112 patients with 231 and 246 implants, respectively. Ti-bar mostly exhibited distal bar extensions (96%) compared to 34% of G-bar (p overdentures supported by soldered gold bars or milled CAD/CAM Ti-bars are a successful treatment modality but require regular maintenance service. These short-term observations support the hypothesis that CAD/CAM Ti-bars reduce technical complications. Fracture location indicated that the titanium thickness around the screw-access hole should be increased. © 2013 Wiley Periodicals, Inc.

Displacement comparison of CAD-CAM titanium and zirconia abutments to implants with different conical connections.

Science.gov (United States)

Yilmaz, Burak; Hashemzadeh, Shervin; Seidt, Jeremy D; Clelland, Nancy L

2018-04-01

To compare the displacements of CAD-CAM zirconia and titanium abutments into different internal connection systems after torquing. OsseoSpeed EV and OsseoSpeed TX implants (n=10) were placed in resin blocks. Zirconia and titanium abutments (n=5) were first hand tightened and then tightened to the recommended torque (20Ncm for TX and 25Ncm for EV). Displacements of abutments between screw tightening by hand and torque driver was measured using three-dimensional digital image correlation (3D DIC) technique. Displacements were measured in U (front/back), V (into/outward), W (right/left) directions and 3-dimensionally (3D). ANOVA with restricted maximum likelihood estimation method was used to analyze the data. Bonferroni-corrected t tests was used to determine the statistical differences (α=0.05). 3D displacement of zirconia and titanium abutments was significantly greater in OsseoSpeed EV implant (PDisplacement of zirconia and titanium abutments was not significantly different within implant systems, 3D (P≥0.386) and in each direction (P≥0.382). In U and V directions, zirconia and titanium abutments displaced significantly more towards negative in OsseoSpeed EV implant (Pdisplaced significantly more in V direction compared to the U and W (P≤0.005), and within the Osseospeed EV system, abutment displacements were significantly different amongst directions and displacements in V were the greatest (Pdisplaced more in the implant that required higher torque values to tighten the abutment. The amount of displacement in both systems was clinically small. Abutment material did not affect the magnitude of displacement. Copyright © 2017 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

Nanoporous hydroxyapatite/sodium titanate bilayer on titanium implants for improved osteointegration.

Science.gov (United States)

Carradò, A; Perrin-Schmitt, F; Le, Q V; Giraudel, M; Fischer, C; Koenig, G; Jacomine, L; Behr, L; Chalom, A; Fiette, L; Morlet, A; Pourroy, G

2017-03-01

The aim of this study was to improve the strength and quality of the titanium-hydroxyapatite interface in order to prevent long-term failure of the implanted devices originating from coating delamination and to test it in an in-vivo model. Ti disks and dental commercial implants were etched in Kroll solution. Thermochemical treatments of the acid-etched titanium were combined with sol-gel hydroxyapatite (HA) coating processes to obtain a nanoporous hydroxyapatite/sodium titanate bilayer. The sodium titanate layer was created by incorporating sodium ions onto the Ti surface during a NaOH alkaline treatment and stabilized using a heat treatment. HA layer was added by dip-coating in a sol-gel solution. The bioactivity was assessed in vitro with murine MC3T3-E1 and human SaOs-2 cells. Functional and histopathological evaluations of the coated Ti implants were performed at 22, 34 and 60days of implantation in a dog lower mandible model. Nanoporous hydroxyapatite/sodium titanate bilayer on titanium implants was sensitive neither to crack propagation nor to layer delamination. The in vitro results on murine MC3T3-E1 and human SaOs-2 cells confirm the advantage of this coating regarding the capacity of cell growth and differentiation. Signs of progressive bone incorporation, such as cancellous bone formed in contact with the implant over the existing compact bone, were notable as early as day 22. Overall, osteoconduction and osteointegration mean scores were higher for test implants compared to the controls at 22 and 34 days. Nanoporous hydroxyapatite/sodium titanate bilayer improves the in-vivo osteoconduction and osteointegration. It prevents the delamination during the screwing and it could increase HA-coated dental implant stability without adhesive failures. The combination of thermochemical treatments with dip coating is a low-cost strategy. Copyright © 2017 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Hollow Mill for Extraction of Stripped Titanium Screws: An Easy ...

African Journals Online (AJOL)

countries. The known alternative in such condition is ... Key words: Hollow mill, stripped screws, titanium locked plates ... used a locally manufactured stainless steel hollow mill, ... head ‑ plate hole” assembly as a mono‑block single unit. In.

Loss of mechanical properties in vivo and bone-implant interface strength of AZ31B magnesium alloy screws with Si-containing coating.

Science.gov (United States)

Tan, Lili; Wang, Qiang; Lin, Xiao; Wan, Peng; Zhang, Guangdao; Zhang, Qiang; Yang, Ke

2014-05-01

In this study the loss of mechanical properties and the interface strength of coated AZ31B magnesium alloy (a magnesium-aluminum alloy) screws with surrounding host tissues were investigated and compared with non-coated AZ31B, degradable polymer and biostable titanium alloy screws in a rabbit animal model after 1, 4, 12 and 21weeks of implantation. The interface strength was evaluated in terms of the extraction torque required to back out the screws. The loss of mechanical properties over time was indicated by one-point bending load loss of the screws after these were extracted at different times. AZ31B samples with a silicon-containing coating had a decreased degradation rate and improved biological properties. The extraction torque of Ti6Al4V, poly-l-lactide (PLLA) and coated AZ31B increased significantly from 1week to 4weeks post-implantation, indicating a rapid osteosynthesis process over 3weeks. The extraction torque of coated AZ31B increased with implantation time, and was higher than that of PLLA after 4weeks of implantation, equalling that of Ti6Al4V at 12weeks and was higher at 21weeks. The bending loads of non-coated AZ31B and PLLA screws degraded sharply after implantation, and that of coated AZ31B degraded more slowly. The biodegradation mechanism, the coating to control the degradation rate and the bioactivity of magnesium alloys influencing the mechanical properties loss over time and bone-implant interface strength are discussed in this study and it is concluded that a suitable degradation rate will result in an improvement in the mechanical performance of magnesium alloys, making them more suitable for clinical application. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

A comparative study of gold UCLA-type and CAD/CAM titanium implant abutments

Science.gov (United States)

Park, Ji-Man; Lee, Jai-Bong; Heo, Seong-Joo

2014-01-01

PURPOSE The aim of this study was to evaluate the interface accuracy of computer-assisted designed and manufactured (CAD/CAM) titanium abutments and implant fixture compared to gold-cast UCLA abutments. MATERIALS AND METHODS An external connection implant system (Mark III, n=10) and an internal connection implant system (Replace Select, n=10) were used, 5 of each group were connected to milled titanium abutment and the rest were connected to the gold-cast UCLA abutments. The implant fixture and abutment were tightened to torque of 35 Ncm using a digital torque gauge, and initial detorque values were measured 10 minutes after tightening. To mimic the mastication, a cyclic loading was applied at 14 Hz for one million cycles, with the stress amplitude range being within 0 N to 100 N. After the cyclic loading, detorque values were measured again. The fixture-abutment gaps were measured under a microscope and recorded with an accuracy of ±0.1 µm at 50 points. RESULTS Initial detorque values of milled abutment were significantly higher than those of cast abutment (P.05). After cyclic loading, detorque values of cast abutment increased, but those of milled abutment decreased (Pabutment group and the cast abutment group after cyclic loading. CONCLUSION In conclusion, CAD/CAM milled titanium abutment can be fabricated with sufficient accuracy to permit screw joint stability between abutment and fixture comparable to that of the traditional gold cast UCLA abutment. PMID:24605206

Influence of bacterial colonization of the healing screws on peri-implant tissue

Directory of Open Access Journals (Sweden)

Simonetta D'Ercole

2013-06-01

Conclusion: The healing screws left in situ for a period of 90 days caused a peri-implant inflammation and the presence of periodontal pathogenic bacteria in the peri-implant sulcus, due to the plaque accumulation on screw surfaces.

Cranioplasty with individual titanium implants

Science.gov (United States)

Mishinov, S.; Stupak, V.; Sadovoy, M.; Mamonova, E.; Koporushko, N.; Larkin, V.; Novokshonov, A.; Dolzhenko, D.; Panchenko, A.; Desyatykh, I.; Krasovsky, I.

2017-09-01

Cranioplasty is the second procedure in the history of neurosurgery after trepanation, and it is still relevant despite the development of civilization and progress in medicine. Each cranioplasty operation is unique because there are no two patients with identical defects of the skull bones. The development of Direct Metal Laser Sintering (DMLS) technique opened up the possibility of direct implant printing of titanium, a biocompatible metal used in medicine. This eliminates the need for producing any intermediate products to create the desired implant. We have produced 8 patient-specific titanium implants using this technique for patients who underwent different decompressive cranioectomies associated with bone tumors. Follow-up duration ranged from 6 to 12 months. We observed no implant-related reactions or complications. In all cases of reconstructive neurosurgery we achieved good clinical and aesthetic results. The analysis of the literature and our own experience in three-dimensional modeling, prototyping, and printing suggests that direct laser sintering of titanium is the optimal method to produce biocompatible surgical implants.

Optimization of spinal implant screw for lower vertebra through finite element studies.

Science.gov (United States)

Biswas, Jayanta; Karmakar, Santanu; Majumder, Santanu; Banerjee, Partha Sarathi; Saha, Subrata; Roychowdhury, Amit

2014-01-01

The increasing older population is suffering from an increase in age-related spinal degeneration that causes tremendous pain. Spine injury is mostly indicated at the lumbar spine (L3-L5) and corresponding intervertebral disks. Finite element analysis (FEA) is now one of the most efficient and accepted tools used to simulate these pathological conditions in computer-assisted design (CAD) models. In this study, L3-L5 spines were modeled, and FEA was performed to formulate optimal remedial measures. Three different loads (420, 490.5, and 588.6 N) based on three body weights (70, 90, and 120 kg) were applied at the top surface of the L3 vertebra, while the lower surface of the L5 vertebra remained fixed. Models of implants using stainless steel and titanium alloy (Ti6Al4V) pedicle screws and rods with three different diameters (4, 5, and 6 mm) were inserted into the spine models. The relative strengths of bone (very weak, weak, standard, strong, and very strong) were considered to determine the patient-specific effect. A total of 90 models were simulated, and von Mises stress and strain, shear stress, and strain intensity contour at the bone-implant interface were analyzed. Results of these analyses indicate that the 6-mm pedicle screw diameter is optimal for most cases. Experimental and clinical validation are needed to confirm these theoretical results.

Covering the screw-access holes of implant restorations in the esthetic zone: a clinical report.

Directory of Open Access Journals (Sweden)

Abolfazl Saboury

2014-12-01

Full Text Available Screw-retained implant restorations have an advantage of predictable retention as well as retrievability, and obviate the risk of excessive sub-gingival cement commonly associated with cement retained implant restorations. Screw-retained restorations generally have screw access holes, which can compromise esthetics and weaken the porcelain around the holes. The purpose of this study is to describe the use of a separate overcasting crown design to cover the screw access hole of implant screw-retained prosthesis for improved esthetics.

Porous Titanium for Dental Implant Applications

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Zena J. Wally

2015-10-01

Full Text Available Recently, an increasing amount of research has focused on the biological and mechanical behavior of highly porous structures of metallic biomaterials, as implant materials for dental implants. Particularly, pure titanium and its alloys are typically used due to their outstanding mechanical and biological properties. However, these materials have high stiffness (Young’s modulus in comparison to that of the host bone, which necessitates careful implant design to ensure appropriate distribution of stresses to the adjoining bone, to avoid stress-shielding or overloading, both of which lead to bone resorption. Additionally, many coating and roughening techniques are used to improve cell and bone-bonding to the implant surface. To date, several studies have revealed that porous geometry may be a promising alternative to bulk structures for dental implant applications. This review aims to summarize the evidence in the literature for the importance of porosity in the integration of dental implants with bone tissue and the different fabrication methods currently being investigated. In particular, additive manufacturing shows promise as a technique to control pore size and shape for optimum biological properties.

Direct Metal Laser Sintering Titanium Dental Implants: A Review of the Current Literature

Science.gov (United States)

Mangano, F.; Chambrone, L.; van Noort, R.; Miller, C.; Hatton, P.; Mangano, C.

2014-01-01

Statement of Problem. Direct metal laser sintering (DMLS) is a technology that allows fabrication of complex-shaped objects from powder-based materials, according to a three-dimensional (3D) computer model. With DMLS, it is possible to fabricate titanium dental implants with an inherently porous surface, a key property required of implantation devices. Objective. The aim of this review was to evaluate the evidence for the reliability of DMLS titanium dental implants and their clinical and histologic/histomorphometric outcomes, as well as their mechanical properties. Materials and Methods. Electronic database searches were performed. Inclusion criteria were clinical and radiographic studies, histologic/histomorphometric studies in humans and animals, mechanical evaluations, and in vitro cell culture studies on DMLS titanium implants. Meta-analysis could be performed only for randomized controlled trials (RCTs); to evaluate the methodological quality of observational human studies, the Newcastle-Ottawa scale (NOS) was used. Results. Twenty-seven studies were included in this review. No RCTs were found, and meta-analysis could not be performed. The outcomes of observational human studies were assessed using the NOS: these studies showed medium methodological quality. Conclusions. Several studies have demonstrated the potential for the use of DMLS titanium implants. However, further studies that demonstrate the benefits of DMLS implants over conventional implants are needed. PMID:25525434

Direct metal laser sintering titanium dental implants: a review of the current literature.

Science.gov (United States)

Mangano, F; Chambrone, L; van Noort, R; Miller, C; Hatton, P; Mangano, C

2014-01-01

Statement of Problem. Direct metal laser sintering (DMLS) is a technology that allows fabrication of complex-shaped objects from powder-based materials, according to a three-dimensional (3D) computer model. With DMLS, it is possible to fabricate titanium dental implants with an inherently porous surface, a key property required of implantation devices. Objective. The aim of this review was to evaluate the evidence for the reliability of DMLS titanium dental implants and their clinical and histologic/histomorphometric outcomes, as well as their mechanical properties. Materials and Methods. Electronic database searches were performed. Inclusion criteria were clinical and radiographic studies, histologic/histomorphometric studies in humans and animals, mechanical evaluations, and in vitro cell culture studies on DMLS titanium implants. Meta-analysis could be performed only for randomized controlled trials (RCTs); to evaluate the methodological quality of observational human studies, the Newcastle-Ottawa scale (NOS) was used. Results. Twenty-seven studies were included in this review. No RCTs were found, and meta-analysis could not be performed. The outcomes of observational human studies were assessed using the NOS: these studies showed medium methodological quality. Conclusions. Several studies have demonstrated the potential for the use of DMLS titanium implants. However, further studies that demonstrate the benefits of DMLS implants over conventional implants are needed.

Direct Metal Laser Sintering Titanium Dental Implants: A Review of the Current Literature

Directory of Open Access Journals (Sweden)

F. Mangano

2014-01-01

Full Text Available Statement of Problem. Direct metal laser sintering (DMLS is a technology that allows fabrication of complex-shaped objects from powder-based materials, according to a three-dimensional (3D computer model. With DMLS, it is possible to fabricate titanium dental implants with an inherently porous surface, a key property required of implantation devices. Objective. The aim of this review was to evaluate the evidence for the reliability of DMLS titanium dental implants and their clinical and histologic/histomorphometric outcomes, as well as their mechanical properties. Materials and Methods. Electronic database searches were performed. Inclusion criteria were clinical and radiographic studies, histologic/histomorphometric studies in humans and animals, mechanical evaluations, and in vitro cell culture studies on DMLS titanium implants. Meta-analysis could be performed only for randomized controlled trials (RCTs; to evaluate the methodological quality of observational human studies, the Newcastle-Ottawa scale (NOS was used. Results. Twenty-seven studies were included in this review. No RCTs were found, and meta-analysis could not be performed. The outcomes of observational human studies were assessed using the NOS: these studies showed medium methodological quality. Conclusions. Several studies have demonstrated the potential for the use of DMLS titanium implants. However, further studies that demonstrate the benefits of DMLS implants over conventional implants are needed.

Factors influencing success of cement versus screw-retained implant restorations: a clinical review

Directory of Open Access Journals (Sweden)

Ahmad Manawar

2012-10-01

Full Text Available Aim: As more and more dental practitioners are focusing on implant-supported fixed restorations, some clinicians favor the use of cement retained restorations while others consider screw retained prosthesis to be the best choice. Discussion: In screw-retained restorations, the fastening screw provides a solid joint between the restoration and the implant abutment, while in cement-retained prostheses the restorative screw is eliminated to enhance esthetics, occlusal stability, and passive fit of the restorations. The factors that influence the type of fixation of the prostheses to the implants like passivity of the framework, ease of fabrication, occlusion, esthetics, accessibility, retention and retrievability are discussed in this article with scientific studies demonstrating superior outcomes of one technique over another. Screwretained implant restorations have an advantage of predictable retention, retrievability and lack of potentially retained subgingival cement. However, a few disadvantages exist such as precise placement of the implant for optimal and esthetic location of the screw access hole and obtaining passive fit. On the other hand, cement retained restorations eliminate unesthetic screw access holes, have passive fit of castings, reduced complexity of clinical and lab procedures, enhanced esthetics, reduced cost factors and non disrupted morphology of the occlusal table. Conclusion: This article compares the advantages, potential disadvantages and limitations of screw and cement retained restorations and their specific implications in the most common clinical situation.

Evaluation of MR issues for the latest standard brands of orthopedic metal implants: plates and screws.

Science.gov (United States)

Zou, Yue-Fen; Chu, Bin; Wang, Chuan-Bing; Hu, Zhi-Yi

2015-03-01

The study was performed to evaluate magnetic resonance (MR) issues for the latest standard brands of plates and screws used in orthopedic surgery at a 1.5-T MR system, including the safety and metallic artifacts. The plates and screws (made of titanium alloy and stainless steel materials, according to the latest standard brands) were assessed for displacement in degrees, MRI-related heating and artifacts at a 1.5-T MR system. The displacement in degrees of the plates and screws was evaluated on an angel-measurement instrument at the entrance of the MR scanner. The MRI-related heating was assessed on a swine leg fixed with a plate by using a "worst-case" pulse sequence. A rectangular water phantom was designed to evaluate metallic artifacts of a screw on different sequences (T1/T2-weighted FSE, STIR, T2-FSE fat saturation, GRE, DWI) and then artifacts were evaluated on T2-weighted FSE sequence by modifying the scanning parameters including field of view (FOV), echo train length (ETL) and bandwidth to identify the influence of parameters on metallic artifacts. 15 volunteers with internal vertebral fixation (titanium alloy materials) were scanned with MR using axial and sagittal T2-FSE, sagittal T2-FSE fat suppression and STIR with conventional and optimized parameters, respectively. Then all images were graded by two experienced radiologists having the experience of more than 7 years under double-blind studies that is neither of them knew which was conventional parameter group and optimized parameter group. The average deflection angle of titanium alloy and stainless steel implants were 4.3° and 7.7°, respectively, (less than 45°) which indicated that the magnetically induced force was less than the weight of the object. The deflection angle of the titanium alloy implants was less than the stainless steel one (t=9.69, Ptitanium alloy before and after the scan was 0.48°C and stainless steel implants was 0.74°C, respectively, with the background temperature

Is galvanic corrosion between titanium alloy and stainless steel spinal implants a clinical concern?

Science.gov (United States)

Serhan, Hassan; Slivka, Michael; Albert, Todd; Kwak, S Daniel

2004-01-01

Surgeons are hesitant to mix components made of differing metal classes for fear of galvanic corrosion complications. However, in vitro studies have failed to show a significant potential for galvanic corrosion between titanium and stainless steel, the two primary metallic alloys used for spinal implants. Galvanic corrosion resulting from metal mixing has not been described in the literature for spinal implant systems. To determine whether galvanic potential significantly affects in vitro corrosion of titanium and stainless steel spinal implant components during cyclical compression bending. Bilateral spinal implant constructs consisting of pedicle screws, slotted connectors, 6.35-mm diameter rods and a transverse rod connector assembled in polyethylene test blocks were tested in vitro. Two constructs had stainless steel rods with mixed stainless steel (SS-SS) and titanium (SS-Ti) components, and two constructs had titanium rods with mixed stainless steel (Ti-SS) and titanium (Ti-Ti) components. Each construct was immersed in phosphate-buffered saline (pH 7.4) at 37 C and tested in cyclic compression bending using a sinusoidal load-controlling function with a peak load of 300 N and a frequency of 5 Hz until a level of 5 million cycles was reached. The samples were then removed and analyzed visually for evidence of corrosion. In addition, scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS) were used to evaluate the extent of corrosion at the interconnections. None of the constructs failed during testing. Gross observation of the implant components after disassembly revealed that no corrosion had occurred on the surface of the implants that had not been in contact with another component. The Ti-Ti interfaces showed some minor signs of corrosion only detectable using SEM and EDS. The greatest amount of corrosion occurred at the SS-SS interfaces and was qualitatively less at the SS-Ti and Ti-SS interfaces. The results from this study indicate

A technique for the management of screw access opening in cement-retained implant restorations

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Hamid Kermanshah

2014-01-01

Full Text Available Introduction: Abutment screw loosening has been considered as a common complication of implant-supported dental prostheses. This problem is more important in cement-retained implant restorations due to their invisible position of the screw access opening. Case Report: This report describes a modified retrievability method for cement-retained implant restorations in the event of abutment screw loosening. The screw access opening was marked with ceramic stain and its porcelain surface was treated using hydrofluoric acid (HF, silane, and adhesive to bond to composite resin. Discussion: The present modified technique facilitates screw access opening and improves the bond between the porcelain and composite resin.

Numerical assessment of bone remodeling around conventionally and early loaded titanium and titanium-zirconium alloy dental implants.

Science.gov (United States)

Akça, Kıvanç; Eser, Atılım; Çavuşoğlu, Yeliz; Sağırkaya, Elçin; Çehreli, Murat Cavit

2015-05-01

The aim of this study was to investigate conventionally and early loaded titanium and titanium-zirconium alloy implants by three-dimensional finite element stress analysis. Three-dimensional model of a dental implant was created and a thread area was established as a region of interest in trabecular bone to study a localized part of the global model with a refined mesh. The peri-implant tissues around conventionally loaded (model 1) and early loaded (model 2) implants were implemented and were used to explore principal stresses, displacement values, and equivalent strains in the peri-implant region of titanium and titanium-zirconium implants under static load of 300 N with or without 30° inclination applied on top of the abutment surface. Under axial loading, principal stresses in both models were comparable for both implants and models. Under oblique loading, principal stresses around titanium-zirconium implants were slightly higher in both models. Comparable stress magnitudes were observed in both models. The displacement values and equivalent strain amplitudes around both implants and models were similar. Peri-implant bone around titanium and titanium-zirconium implants experiences similar stress magnitudes coupled with intraosseous implant displacement values under conventional loading and early loading simulations. Titanium-zirconium implants have biomechanical outcome comparable to conventional titanium implants under conventional loading and early loading.

In vitro comparative analysis of the fit of gold alloy or commercially pure titanium implant-supported prostheses before and after electroerosion.

Science.gov (United States)

Sartori, Ivete Aparecida de Mattias; Ribeiro, Ricardo Faria; Francischone, Carlos Eduardo; de Mattos, Maria da Gloria Chiarello

2004-08-01

For implant-supported prostheses, passive fit is critical for the success of rehabilitation, especially when alternative materials are used. The purpose of this study was to compare interfacial fit of implant-supported prostheses cast in titanium to those cast in gold alloy. Five 3-unit fixed partial dentures were fabricated in gold alloy (Degudent U) as 1-piece castings, and 5 others were similarly cast in commercially pure titanium (Grade 1). The interfacial gaps between the prostheses and the abutments were evaluated with an optical microscope, before and after electroerosion. Readings were made with both screws tightened (10 N.cm torque), and with only 1 side tightened, so as to also evaluate the passive fit of the prostheses. Data were compared statistically by 2-way analysis of variance and the post hoc Tukey multiple range test (alpha=.05). Before electroerosion, the interfacial gaps for the 1-piece prostheses were significantly smaller (Pelectroerosion procedure significantly (Pelectroerosion did not present significant differences when the side opposite the tightened side was analyzed, but the gold alloy group showed better fit when the tightened side was analyzed (12.8 +/- 1.4 microm for gold alloy; 29.6 +/- 4.4 microm for titanium) and when both screws were tightened (5.4 +/- 2.3 microm for gold alloy; 16.1 +/- 5.5 microm for titanium). Cast titanium prostheses, despite showing larger interfacial gaps between the prosthesis and abutment than those obtained with gold alloy, had improved fit after being subjected to electroerosion.

Guidelines for patient-specific jawline definition with titanium implants in esthetic, deformity, and malformation surgery.

Science.gov (United States)

Mommaerts, Maurice Yves

2016-01-01

Asymmetry and unfavorable esthetics of the jawline have become possible to correct in three dimensions using computer aided design and computer aided manufacturing. The aim of this study was to provide esthetic, technical, and operative guidelines for mandibular angle and border augmentation using patient-specific titanium implants made by selective laser melting. University hospital - prospective registry. Twelve patients and 17 implantation sites were documented and prospectively registered. Malformational, deformational, and purely esthetic indications were encountered. Descriptive. Patient satisfaction was high, probably because the patients had input into the planned dimensions and shape. A serious infection with implant removal occurred in one patient who had six previous surgeries at the same sites. Technical and surgical guidelines were developed including splitting implants into two segments when the mental nerve was at risk, using a three-dimensional (3D) puzzle connection, providing at least two screw holes per segment, using scaffolds at the bony contact side, using a "satin" finish at the periosteal side, referring to anatomical structures where possible, making provisions for transbuccal and transoral fixation, using a high vestibular incision, and using a double-layer closure. Esthetic guidelines are discussed but could not be upgraded. Mirroring techniques and 3D print accuracy up to 0.1 mm allow precise planning of jaw angle implants. Patients are pleased when given preoperative renderings for their consideration. Infections can be managed using technical and operative recommendations and careful patient selection.

Non-Destructive Analysis of Basic Surface Characteristics of Titanium Dental Implants Made by Miniature Machining

Science.gov (United States)

Babík, Ondrej; Czán, Andrej; Holubják, Jozef; Kameník, Roman; Pilc, Jozef

2016-12-01

One of the most best-known characteristic and important requirement of dental implant is made of biomaterials ability to create correct interaction between implant and human body. The most implemented material in manufacturing of dental implants is titanium of different grades of pureness. Since most of the implant surface is in direct contact with bone tissue, shape and integrity of said surface has great influence on the successful osseointegration. Among other characteristics of titanium that predetermine ideal biomaterial, it shows a high mechanical strength making precise machining miniature Increasingly difficult. The article is focused on evaluation of the resulting quality, integrity and characteristics of dental implants surface after machining.

Artefacts in multimodal imaging of titanium, zirconium and binary titanium-zirconium alloy dental implants: an in vitro study.

Science.gov (United States)

Smeets, Ralf; Schöllchen, Maximilian; Gauer, Tobias; Aarabi, Ghazal; Assaf, Alexandre T; Rendenbach, Carsten; Beck-Broichsitter, Benedicta; Semmusch, Jan; Sedlacik, Jan; Heiland, Max; Fiehler, Jens; Siemonsen, Susanne

2017-02-01

To analyze and evaluate imaging artefacts induced by zirconium, titanium and titanium-zirconium alloy dental implants. Zirconium, titanium and titanium-zirconium alloy implants were embedded in gelatin and MRI, CT and CBCT were performed. Standard protocols were used for each modality. For MRI, line-distance profiles were plotted to quantify the accuracy of size determination. For CT and CBCT, six shells surrounding the implant were defined every 0.5 cm from the implant surface and histogram parameters were determined for each shell. While titanium and titanium-zirconium alloy induced extensive signal voids in MRI owing to strong susceptibility, zirconium implants were clearly definable with only minor distortion artefacts. For titanium and titanium-zirconium alloy, the MR signal was attenuated up to 14.1 mm from the implant. In CT, titanium and titanium-zirconium alloy resulted in less streak artefacts in comparison with zirconium. In CBCT, titanium-zirconium alloy induced more severe artefacts than zirconium and titanium. MRI allows for an excellent image contrast and limited artefacts in patients with zirconium implants. CT and CBCT examinations are less affected by artefacts from titanium and titanium-zirconium alloy implants compared with MRI. The knowledge about differences of artefacts through different implant materials and image modalities might help support clinical decisions for the choice of implant material or imaging device in the clinical setting.

Clinical experiences with laser-welded titanium frameworks supported by implants in the edentulous mandible: a 5-year follow-up study.

Science.gov (United States)

Ortorp, A; Linden, B; Jemt, T

1999-01-01

The purpose of this study was to report the 5-year clinical performance of implant-supported prostheses with laser-welded titanium frameworks and to compare their performance with that of prostheses provided with conventional cast frameworks. On a routine basis, a consecutive group of 824 edentulous patients were provided with fixed prostheses supported by implants in the edentulous mandible. In addition to conventional gold-alloy castings, patients were at random provided with 2 kinds of laser-welded titanium frameworks. In all, 155 patients were included in the 2 titanium framework groups. A control group of 53 randomly selected patients with conventional gold-alloy castings was used for comparison. Clinical and radiographic 5-year data was collected for the 3 groups. All followed patients still had fixed prostheses in the mandible after 5 years. The overall cumulative success rates were 95.9% and 99.7% for titanium-framework prostheses and implants, respectively. The corresponding success rates for the control group were 100% and 99.6%, respectively. Bone loss was 0.5 mm on average during the 5-year follow-up period. The most common complications for titanium frameworks were resin or tooth fractures, gingival inflammation, and fractures of the metal frames (10%). One of the cast frameworks fractured and was resoldered. Loose and fractured implant screw components were few (laser-welded titanium frameworks seem to be a viable alternative to conventional castings in the edentulous mandible.

Enhancement of Orthodontic Anchor Screw Stability Under Immediate Loading by Ultraviolet Photofunctionalization Technology.

Science.gov (United States)

Takahashi, Maiko; Motoyoshi, Mitsuru; Inaba, Mizuki; Hagiwara, Yoshiyuki; Shimizu, Noriyoshi

Ultraviolet (UV)-mediated photofunctionalization technology is intended to enhance the osseointegration capability of titanium implants. There are concerns about orthodontic anchor screws loosening under immediate loading protocols in adolescent orthodontic treatment. The purpose of this in vivo study was to evaluate the effects of photofunctionalization on the intrabony stability of orthodontic titanium anchor screws and bone-anchor screw contact under immediate loading in growing rats. Custom-made titanium anchor screws (1.4 mm in diameter and 4.0 mm in length) with or without photofunctionalization pretreatment were placed on the proximal epiphysis of the tibial bone in 6-week-old male Sprague-Dawley rats and were loaded immediately after placement. After 2 weeks of loading, the stability of the anchor screws was evaluated using a Periotest device, and the bone-anchor screw contact ratio (BSC) was assessed by a histomorphometric analysis using field-emission scanning electron microscopy. In the unloaded group, Periotest values (PTVs) were ~25 for UV-untreated screws and 13 for UVtreated screws (P < .01), while in the immediate-loading group, PTVs were 28 for UV-untreated screws and 16 for UV-treated screws (P < .05). Significantly less screw mobility was observed in both UV-treated groups regardless of the loading protocol. The BSC was increased ~1.8 fold for UV-treated screws, compared with UV-untreated screws, regardless of the loading protocol. Photofunctionalization enhanced the intrabony stability of orthodontic anchor screws under immediate loading in growing rats by increasing bone-anchor screw contact.

Customizable cap implants for neurophysiological experimentation.

Science.gov (United States)

Blonde, Jackson D; Roussy, Megan; Luna, Rogelio; Mahmoudian, Borna; Gulli, Roberto A; Barker, Kevin C; Lau, Jonathan C; Martinez-Trujillo, Julio C

2018-04-22

Several primate neurophysiology laboratories have adopted acrylic-free, custom-fit cranial implants. These implants are often comprised of titanium or plastic polymers, such as polyether ether ketone (PEEK). Titanium is favored for its mechanical strength and osseointegrative properties whereas PEEK is notable for its lightweight, machinability, and MRI compatibility. Recent titanium/PEEK implants have proven to be effective in minimizing infection and implant failure, thereby prolonging experiments and optimizing the scientific contribution of a single primate. We created novel, customizable PEEK 'cap' implants that contour to the primate's skull. The implants were created using MRI and/or CT data, SolidWorks software and CNC-machining. Three rhesus macaques were implanted with a PEEK cap implant. Head fixation and chronic recordings were successfully performed. Improvements in design and surgical technique solved issues of granulation tissue formation and headpost screw breakage. Primate cranial implants have traditionally been fastened to the skull using acrylic and anchor screws. This technique is prone to skin recession, infection, and implant failure. More recent methods have used imaging data to create custom-fit titanium/PEEK implants with radially extending feet or vertical columns. Compared to our design, these implants are more surgically invasive over time, have less force distribution, and/or do not optimize the utilizable surface area of the skull. Our PEEK cap implants served as an effective and affordable means to perform electrophysiological experimentation while reducing surgical invasiveness, providing increased strength, and optimizing useful surface area. Crown Copyright © 2018. Published by Elsevier B.V. All rights reserved.

Multicycle mechanical performance of titanium and stainless steel transpedicular spine implants.

Science.gov (United States)

Pienkowski, D; Stephens, G C; Doers, T M; Hamilton, D M

1998-04-01

This was a prospective in vitro study comparing titanium alloy and stainless steel alloy in transpedicular spine implants from two different manufactures. To compare the multicycle mechanical performance of these two alloys, used in each of two different implant designs. Transpedicular spine implants primarily have been manufactured from stainless steel, but titanium alloy offers imaging advantages. However, the notch sensitivity of titanium alloy has caused concern regarding how implants made from this material will compare in stiffness and fatigue life with implants made from stainless steel. Twenty-four implants (two alloys, two designs, six implants per group) were mounted in machined polyethylene wafers and repetitively loaded (up to 1 million cycles) from 80 N to 800 N using a 5-Hertz sinusoidal waveform. Load and displacement data were automatically and periodically sampled throughout the entire test. Implant stiffness increased with cycle load number, reached a steady state, then declined just before fatigue failure. Stiffness varied less in titanium transpedicular spine implants than in their stainless counterparts. All stainless steel implant types were stiffer (steady-state value, P titanium alloy counterparts. One titanium implant design failed with fewer (P stainless steel counterpart, whereas a stainless steel implant of another design failed with fewer (P titanium counterpart. Overall, fatigue life, i.e., the total number of load cycles until failure, was related to implant type (P implant material. A transpedicular spine implant's fatigue lifetime depends on both the design and the material and cannot be judged on material alone. Stainless steel implants are stiffer than titanium alloy implants of equal design and size; however, for those designs in which the fatigue life of the titanium alloy version is superior, enlargement of the implant's components can compensate for titanium's lower modulus of elasticity and result in an implant equally stiff

Influence of abutment materials on the implant-abutment joint stability in internal conical connection type implant systems

OpenAIRE

Jo, Jae-Young; Yang, Dong-Seok; Huh, Jung-Bo; Heo, Jae-Chan; Yun, Mi-Jung; Jeong, Chang-Mo

2014-01-01

PURPOSE This study evaluated the influence of abutment materials on the stability of the implant-abutment joint in internal conical connection type implant systems. MATERIALS AND METHODS Internal conical connection type implants, cement-retained abutments, and tungsten carbide-coated abutment screws were used. The abutments were fabricated with commercially pure grade 3 titanium (group T3), commercially pure grade 4 titanium (group T4), or Ti-6Al-4V (group TA) (n=5, each). In order to assess ...

Rough surfaces of titanium and titanium alloys for implants and prostheses

International Nuclear Information System (INIS)

Conforto, E.; Aronsson, B.-O.; Salito, A.; Crestou, C.; Caillard, D.

2004-01-01

Titanium and titanium alloys for dental implants and hip prostheses were surface-treated and/or covered by metallic or ceramic rough layers after being submitted to sand blasting. The goal of these treatments is to improve the surface roughness and consequently the osteointegration, the fixation, and the stability of the implant. The microstructure of titanium and titanium alloys submitted to these treatments has been studied and correlated to their mechanical behavior. As-treated/covered and mechanically tested surfaces were characterized by scanning electron microscopy (SEM). Structural analyses performed by transmission electron microscopy (TEM), mainly in cross-section, reveal the degree of adherence and cohesion between the surface layer and the substrate (implant). We observed that, although the same convenient surface roughness was obtained with the two types of process, many characteristics as structural properties and mechanical behavior are very different

Osseointegration is improved by coating titanium implants with a nanostructured thin film with titanium carbide and titanium oxides clustered around graphitic carbon

International Nuclear Information System (INIS)

Veronesi, Francesca; Giavaresi, Gianluca; Fini, Milena; Longo, Giovanni; Ioannidu, Caterina Alexandra; Scotto d'Abusco, Anna; Superti, Fabiana; Panzini, Gianluca; Misiano, Carlo; Palattella, Alberto; Selleri, Paolo; Di Girolamo, Nicola; Garbarino, Viola; Politi, Laura; Scandurra, Roberto

2017-01-01

Titanium implants coated with a 500 nm nanostructured layer, deposited by the Ion Plating Plasma Assisted (IPPA) technology, composed of 60% graphitic carbon, 25% titanium oxides and 15% titanium carbide were implanted into rabbit femurs whilst into the controlateral femurs uncoated titanium implants were inserted as control. At four time points the animals were injected with calcein green, xylenol orange, oxytetracycline and alizarin. After 2, 4 and 8 weeks femurs were removed and processed for histology and static and dynamic histomorphometry for undecalcified bone processing into methylmethacrylate, sectioned, thinned, polished and stained with Toluidine blue and Fast green. The overall bone-implant contacts rate (percentage of bone-implant contacts/weeks) of the TiC coated implant was 1.6 fold than that of the uncoated titanium implant. The histomorphometric analyses confirmed the histological evaluations. More precisely, higher Mineral Apposition Rate (MAR, μm/day) (p < 0.005) and Bone Formation Rate (BFR, μm 2 /μm/day) (p < 0.0005) as well as Bone Implant Contact (Bic) and Bone Ingrowth values (p < 0.0005) were observed for the TiC coated implants compared to uncoated implants. In conclusion the hard nanostructured TiC layer protects the bulk titanium implant against the harsh conditions of biological tissues and in the same time, stimulating adhesion, proliferation and activity of osteoblasts, induces a better bone-implant contacts of the implant compared to the uncoated titanium implant. - Highlights: • Ti implants were coated with a nanostructured film composed of C gr , TiC and TiO x . • The TiC layer stimulates adhesion, proliferation and activity of osteoblasts. • Uncoated and TiC coated titanium implants were implanted in rabbit femurs. • Bone-implant contacts of TiC coated implants were higher than that of uncoated. • Mineral Apposition Rate of TiC coated implants were higher than that of uncoated.

Hollow Abutment Screw Design for Easy Retrieval in Case of Screw Fracture in Dental Implant System.

Science.gov (United States)

Sim, Bo Kyun; Kim, Bongju; Kim, Min Jeong; Jeong, Guk Hyun; Ju, Kyung Won; Shin, Yoo Jin; Kim, Man Yong; Lee, Jong-Ho

2017-01-01

The prosthetic component of dental implant is attached on the abutment which is connected to the fixture with an abutment screw. The abutment screw fracture is not frequent; however, the retrieval of the fractured screw is not easy, and it poses complications. A retrieval kit was developed which utilizes screw removal drills to make a hole on the fractured screw that provides an engaging drill to unscrew it. To minimize this process, the abutment screw is modified with a prefabricated access hole for easy retrieval. This study aimed to introduce this modified design of the abutment screw, the concept of easy retrieval, and to compare the mechanical strengths of the conventional and hollow abutment screws by finite element analysis (FEA) and mechanical test. In the FEA results, both types of abutment screws showed similar stress distribution in the single artificial tooth system. A maximum load difference of about 2% occurred in the vertical load by a mechanical test. This study showed that the hollow abutment screw may be an alternative to the conventional abutment screws because this is designed for easy retrieval and that both abutment screws showed no significant difference in the mechanical tests and in the FEA.

Surface and corrosion characteristics of carbon plasma implanted and deposited nickel-titanium alloy

International Nuclear Information System (INIS)

Poon, R.W.Y.; Liu, X.Y.; Chung, C.Y.; Chu, P.K.; Yeung, K.W.K.; Lu, W.W.; Cheung, K.M.C.

2005-01-01

Nickel-titanium shape memory alloys (NiTi) are potentially useful in orthopedic implants on account of their super-elastic and shape memory properties. However, the materials are prone to surface corrosion and the most common problem is out-diffusion of harmful Ni ions from the substrate into body tissues and fluids. In order to improve the corrosion resistance and related surface properties, we used the technique of plasma immersion ion implantation and deposition to deposit an amorphous hydrogenated carbon coating onto NiTi and implant carbon into NiTi. Both the deposited amorphous carbon film and carbon plasma implanted samples exhibit much improved corrosion resistances and surface mechanical properties and possible mechanisms are suggested

Osseointegration is improved by coating titanium implants with a nanostructured thin film with titanium carbide and titanium oxides clustered around graphitic carbon

Energy Technology Data Exchange (ETDEWEB)

Veronesi, Francesca [Laboratory of Preclinical and Surgical Studies, Rizzoli Orthopedic Institute, Via Di Barbiano 1/10, Bologna 40136 (Italy); Giavaresi, Gianluca; Fini, Milena [Laboratory of Preclinical and Surgical Studies, Rizzoli Orthopedic Institute, Via Di Barbiano 1/10, Bologna 40136 (Italy); Laboratory of Biocompatibility, Innovative Technologies and Advanced Therapies, Department Rizzoli RIT, Via Di Barbiano 1/10, Bologna 40136 (Italy); Longo, Giovanni [CNR Istituto di Struttura della Materia, CNR, Via del Fosso del Cavaliere 100, 00133 Roma (Italy); Ioannidu, Caterina Alexandra; Scotto d' Abusco, Anna [Dept. of Biochemical Sciences, Sapienza University of Roma, Ple A. Moro 5, 00185 Roma (Italy); Superti, Fabiana; Panzini, Gianluca [Dept. of Technologies and Health, Istituto Superiore di Sanità, Viale Regina Elena, 299 Roma (Italy); Misiano, Carlo [Romana Film Sottili, Anzio, Roma (Italy); Palattella, Alberto [Dept. of Clinical Sciences and Translational Medicine, Tor Vergata University, Via Montpellier 1, 00133 Roma (Italy); Selleri, Paolo; Di Girolamo, Nicola [Exotic Animals Clinic, Via S. Giovannini 53, 00137 Roma (Italy); Garbarino, Viola [Dept. of Radiology, S.M. Goretti Hospital, Via G. Reni 2, 04100 Latina (Italy); Politi, Laura [Dept. of Biochemical Sciences, Sapienza University of Roma, Ple A. Moro 5, 00185 Roma (Italy); Scandurra, Roberto, E-mail: roberto.scandurra@uniroma1.it [Dept. of Biochemical Sciences, Sapienza University of Roma, Ple A. Moro 5, 00185 Roma (Italy)

2017-01-01

Titanium implants coated with a 500 nm nanostructured layer, deposited by the Ion Plating Plasma Assisted (IPPA) technology, composed of 60% graphitic carbon, 25% titanium oxides and 15% titanium carbide were implanted into rabbit femurs whilst into the controlateral femurs uncoated titanium implants were inserted as control. At four time points the animals were injected with calcein green, xylenol orange, oxytetracycline and alizarin. After 2, 4 and 8 weeks femurs were removed and processed for histology and static and dynamic histomorphometry for undecalcified bone processing into methylmethacrylate, sectioned, thinned, polished and stained with Toluidine blue and Fast green. The overall bone-implant contacts rate (percentage of bone-implant contacts/weeks) of the TiC coated implant was 1.6 fold than that of the uncoated titanium implant. The histomorphometric analyses confirmed the histological evaluations. More precisely, higher Mineral Apposition Rate (MAR, μm/day) (p < 0.005) and Bone Formation Rate (BFR, μm{sup 2}/μm/day) (p < 0.0005) as well as Bone Implant Contact (Bic) and Bone Ingrowth values (p < 0.0005) were observed for the TiC coated implants compared to uncoated implants. In conclusion the hard nanostructured TiC layer protects the bulk titanium implant against the harsh conditions of biological tissues and in the same time, stimulating adhesion, proliferation and activity of osteoblasts, induces a better bone-implant contacts of the implant compared to the uncoated titanium implant. - Highlights: • Ti implants were coated with a nanostructured film composed of C{sub gr}, TiC and TiO{sub x}. • The TiC layer stimulates adhesion, proliferation and activity of osteoblasts. • Uncoated and TiC coated titanium implants were implanted in rabbit femurs. • Bone-implant contacts of TiC coated implants were higher than that of uncoated. • Mineral Apposition Rate of TiC coated implants were higher than that of uncoated.

Hollow Abutment Screw Design for Easy Retrieval in Case of Screw Fracture in Dental Implant System

Directory of Open Access Journals (Sweden)

Bo Kyun Sim

2017-01-01

Full Text Available The prosthetic component of dental implant is attached on the abutment which is connected to the fixture with an abutment screw. The abutment screw fracture is not frequent; however, the retrieval of the fractured screw is not easy, and it poses complications. A retrieval kit was developed which utilizes screw removal drills to make a hole on the fractured screw that provides an engaging drill to unscrew it. To minimize this process, the abutment screw is modified with a prefabricated access hole for easy retrieval. This study aimed to introduce this modified design of the abutment screw, the concept of easy retrieval, and to compare the mechanical strengths of the conventional and hollow abutment screws by finite element analysis (FEA and mechanical test. In the FEA results, both types of abutment screws showed similar stress distribution in the single artificial tooth system. A maximum load difference of about 2% occurred in the vertical load by a mechanical test. This study showed that the hollow abutment screw may be an alternative to the conventional abutment screws because this is designed for easy retrieval and that both abutment screws showed no significant difference in the mechanical tests and in the FEA.

Hollow Abutment Screw Design for Easy Retrieval in Case of Screw Fracture in Dental Implant System

Science.gov (United States)

Kim, Bongju; Shin, Yoo Jin

2017-01-01

The prosthetic component of dental implant is attached on the abutment which is connected to the fixture with an abutment screw. The abutment screw fracture is not frequent; however, the retrieval of the fractured screw is not easy, and it poses complications. A retrieval kit was developed which utilizes screw removal drills to make a hole on the fractured screw that provides an engaging drill to unscrew it. To minimize this process, the abutment screw is modified with a prefabricated access hole for easy retrieval. This study aimed to introduce this modified design of the abutment screw, the concept of easy retrieval, and to compare the mechanical strengths of the conventional and hollow abutment screws by finite element analysis (FEA) and mechanical test. In the FEA results, both types of abutment screws showed similar stress distribution in the single artificial tooth system. A maximum load difference of about 2% occurred in the vertical load by a mechanical test. This study showed that the hollow abutment screw may be an alternative to the conventional abutment screws because this is designed for easy retrieval and that both abutment screws showed no significant difference in the mechanical tests and in the FEA. PMID:29065610

Removal torque evaluation of three different abutment screws for single implant restorations after mechanical cyclic loading.

Science.gov (United States)

Paepoemsin, T; Reichart, P A; Chaijareenont, P; Strietzel, F P; Khongkhunthian, P

2016-01-01

The aim of this study was to evaluate the removal torque of three different abutment screws and pull out strength of implant-abutment connection for single implant restorations after mechanical cyclic loading. The study was performed in accordance with ISO 14801:2007. Three implant groups (n=15) were used: group A, PW Plus® with flat head screw; group B, PW Plus® with tapered screw; and group C, Conelog® with flat head screw. All groups had the same implant-abutment connection feature: cone with mandatory index. All screws were tightened with manufacturer's recommended torque. Ten specimens in each group underwent cyclic loading (1×106 cycles, 10 Hz, and 250 N). Then, all specimens were un-tightened, measured for the removal torque, and underwent a tensile test. The force that dislodged abutment from implant fixture was recorded. The data were analysed using independent sample t-test, ANOVA and Tukey HSD test. Before cyclic loading, removal torque in groups A, B and C were significantly different (B> A> C, Pabutment from implant fixture increased immensely after cyclic loading.

Biocompatibility of Advanced Manufactured Titanium Implants-A Review.

Science.gov (United States)

Sidambe, Alfred T

2014-12-19

Titanium (Ti) and its alloys may be processed via advanced powder manufacturing routes such as additive layer manufacturing (or 3D printing) or metal injection moulding. This field is receiving increased attention from various manufacturing sectors including the medical devices sector. It is possible that advanced manufacturing techniques could replace the machining or casting of metal alloys in the manufacture of devices because of associated advantages that include design flexibility, reduced processing costs, reduced waste, and the opportunity to more easily manufacture complex or custom-shaped implants. The emerging advanced manufacturing approaches of metal injection moulding and additive layer manufacturing are receiving particular attention from the implant fabrication industry because they could overcome some of the difficulties associated with traditional implant fabrication techniques such as titanium casting. Using advanced manufacturing, it is also possible to produce more complex porous structures with improved mechanical performance, potentially matching the modulus of elasticity of local bone. While the economic and engineering potential of advanced manufacturing for the manufacture of musculo-skeletal implants is therefore clear, the impact on the biocompatibility of the materials has been less investigated. In this review, the capabilities of advanced powder manufacturing routes in producing components that are suitable for biomedical implant applications are assessed with emphasis placed on surface finishes and porous structures. Given that biocompatibility and host bone response are critical determinants of clinical performance, published studies of in vitro and in vivo research have been considered carefully. The review concludes with a future outlook on advanced Ti production for biomedical implants using powder metallurgy.

Biocompatibility of titanium based implants treated with plasma immersion ion implantation

International Nuclear Information System (INIS)

Maendl, S.; Sader, R.; Thorwarth, G.; Krause, D.; Zeilhofer, H.-F.; Horch, H.H.; Rauschenbach, B.

2003-01-01

In this work, the biocompatibility of titanium before and after oxygen PIII is investigated using a rat animal model. Pure titanium (grade 2) and pre-anodized titanium were implanted with oxygen at elevated temperatures between 200 and 550 deg. C and subsequently analyzed for oxygen content and phase composition. No deterioration of the tensile strength and the yield strength was detected after the implantation. The mechanical stability of the osseointegration was determined with a pull-out test, where an increased shear strength was measured after PIII treatment. Only a slight improvement of the bone contact area, from an already excellent starting value, was observed for pure titanium. In contrast, a significant improvement was found for anodized titanium after PIII treatment. This astonishing difference can be explained with the surface topography and the phase composition of the anodized titanium samples

In Vivo Response of Laser Processed Porous Titanium Implants for Load-Bearing Implants.

Science.gov (United States)

Bandyopadhyay, Amit; Shivaram, Anish; Tarafder, Solaiman; Sahasrabudhe, Himanshu; Banerjee, Dishary; Bose, Susmita

2017-01-01

Applications of porous metallic implants to enhance osseointegration of load-bearing implants are increasing. In this work, porous titanium implants, with 25 vol.% porosity, were manufactured using Laser Engineered Net Shaping (LENS™) to measure the influence of porosity towards bone tissue integration in vivo. Surfaces of the LENS™ processed porous Ti implants were further modified with TiO 2 nanotubes to improve cytocompatibility of these implants. We hypothesized that interconnected porosity created via additive manufacturing will enhance bone tissue integration in vivo. To test our hypothesis, in vivo experiments using a distal femur model of male Sprague-Dawley rats were performed for a period of 4 and 10 weeks. In vivo samples were characterized via micro-computed tomography (CT), histological imaging, scanning electron microscopy, and mechanical push-out tests. Our results indicate that porosity played an important role to establish early stage osseointegration forming strong interfacial bonding between the porous implants and the surrounding tissue, with or without surface modification, compared to dense Ti implants used as a control.

In vivo response of laser processed porous titanium implants for load-bearing implants

Science.gov (United States)

Bandyopadhyay, Amit; Shivaram, Anish; Tarafder, Solaiman; Sahasrabudhe, Himanshu; Banerjee, Dishary; Bose, Susmita

2016-01-01

Applications of porous metallic implants to enhance osseointegration of load-bearing implants are increasing. In this work, porous titanium implants, with 25 volume% porosity, were manufactured using Laser Engineered Net Shaping (LENS™) to measure the influence of porosity towards bone tissue integration in vivo. Surfaces of the LENS™ processed porous Ti implants were further modified with TiO2 nanotubes to improve cytocompatibility of these implants. We hypothesized that interconnected porosity created via additive manufacturing will enhance bone tissue integration in vivo. To test our hypothesis, in vivo experiments using a distal femur model of male Sprague-Dawley rats were performed for a period of 4 and 10 weeks. In vivo samples were characterized via micro-computed tomography (CT), histological imaging, scanning electron microscopy, and mechanical push-out tests. Our results indicate that porosity played an important role to establish early stage osseointegration forming strong interfacial bonding between the porous implants and the surrounding tissue, with or without surface modification, compared to dense Ti implants used as a control. PMID:27307009

Maxillary arch rehabilitation using implant-supported computer-assisted design-computer-assisted manufacturing-milled titanium framework

Directory of Open Access Journals (Sweden)

Tulika S Khanna

2017-01-01

Full Text Available Esthetic and functional rehabilitation of completely edentulous maxillary arch with fixed implant supported prosthesis is a challenging task. Newer technologies such as computer assisted design computer assisted manufacturing (CAD CAM and cone beam conventional tomography play an important role in achieving predictable results. Full mouth porcelain fused to metal (PFM individual crowns on CAD CAM milled titanium framework provides positive esthetic and functional outcome. This is a case report of rehabilitation of partially edentulous maxillary arch patient. Staged rehabilitation of this patient was planned. In the first stage, root canal treatment of key abutment teeth was done, nonsalvageable teeth were removed, and immediate interim overdenture was provided. In the second stage, five Nobel Biocare dental implants were placed. After integration impressions were made, CAD CAM milled titanium bar was fabricated. Individual PFM crowns were made and cemented. This method gives better esthetic compared to acrylic fused to metal hybrid prosthesis with the advantage of retrievability just like screw retained prosthesis. Hence, this technique is good for rehabilitation of patients with high esthetic demands.

Pedicle screw anchorage of carbon fiber-reinforced PEEK screws under cyclic loading.

Science.gov (United States)

Lindtner, Richard A; Schmid, Rene; Nydegger, Thomas; Konschake, Marko; Schmoelz, Werner

2018-03-01

Pedicle screw loosening is a common and significant complication after posterior spinal instrumentation, particularly in osteoporosis. Radiolucent carbon fiber-reinforced polyetheretherketone (CF/PEEK) pedicle screws have been developed recently to overcome drawbacks of conventional metallic screws, such as metal-induced imaging artifacts and interference with postoperative radiotherapy. Beyond radiolucency, CF/PEEK may also be advantageous over standard titanium in terms of pedicle screw loosening due to its unique material properties. However, screw anchorage and loosening of CF/PEEK pedicle screws have not been evaluated yet. The aim of this biomechanical study therefore was to evaluate whether the use of this alternative nonmetallic pedicle screw material affects screw loosening. The hypotheses tested were that (1) nonmetallic CF/PEEK pedicle screws resist an equal or higher number of load cycles until loosening than standard titanium screws and that (2) PMMA cement augmentation further increases the number of load cycles until loosening of CF/PEEK screws. In the first part of the study, left and right pedicles of ten cadaveric lumbar vertebrae (BMD 70.8 mg/cm 3  ± 14.5) were randomly instrumented with either CF/PEEK or standard titanium pedicle screws. In the second part, left and right pedicles of ten vertebrae (BMD 56.3 mg/cm 3  ± 15.8) were randomly instrumented with either PMMA-augmented or nonaugmented CF/PEEK pedicle screws. Each pedicle screw was subjected to cyclic cranio-caudal loading (initial load ranging from - 50 N to + 50 N) with stepwise increasing compressive loads (5 N every 100 cycles) until loosening or a maximum of 10,000 cycles. Angular screw motion ("screw toggling") within the vertebra was measured with a 3D motion analysis system every 100 cycles and by stress fluoroscopy every 500 cycles. The nonmetallic CF/PEEK pedicle screws resisted a similar number of load cycles until loosening as the contralateral standard

Shape memory effect and superelasticity of titanium nickelide alloys implanted with high ion doses

International Nuclear Information System (INIS)

Pogrebnjak, A D; Bratushka, S N; Beresnev, V M; Levintant-Zayonts, N

2013-01-01

The state of the art in ion implantation of superelastic NiTi shape memory alloys is analyzed. Various technological applications of the shape memory effect are outlined. The principles and techiques of ion implantation are described. Specific features of its application for modification of surface layers in surface engineering are considered. Key properties of shape memory alloys and problems in utilization of ion implantation to improve the surface properties of shape memory alloys, such as corrosion resistance, friction coefficient, wear resistance, etc. are discussed. The bibliography includes 162 references

Comparative effect of implant-abutment connections, abutment angulations, and screw lengths on preloaded abutment screw using three-dimensional finite element analysis: An in vitro study

OpenAIRE

Krishna Chaitanya Kanneganti; Dileep Nag Vinnakota; Srinivas Rao Pottem; Mahesh Pulagam

2018-01-01

Purpose: The purpose of this study is to compare the effect of implant-abutment connections, abutment angulations, and screw lengths on screw loosening (SL) of preloaded abutment using three dimensional (3D) finite element analysis. Materials and Methods: 3D models of implants (conical connection with hex/trilobed connections), abutments (straight/angulated), abutment screws (short/long), and crown and bone were designed using software Parametric Technology Corporation Creo and assembled t...

Evaluation of Corrosion Resistance of Titanium Alloys Used for Medical Implants

Directory of Open Access Journals (Sweden)

Szewczenko J.

2016-06-01

Full Text Available The study presents the results of investigations of modeling the usable properties of implant surfaces made of Ti6Al7Nb alloy, using the example of a dynamic hip screw (DHS applied in surgical treatment of intertrochanteric femoral neck fractures. Numerical simulation has been performed for the model load of femoral fixation with DHS screw. The load simulation results provided the basis to select mechanical properties of the fixator elements and to define those fixation areas which are mostly susceptible to development of corrosion. The surfaces of Ti6Al7Nb alloy were ground, vibro-abrasive machined, mechanically polished, sandblasted, anode oxidized at different voltage values and steam sterilized. Results of surface topography evaluation, resistance to pitting and crevice corrosion as well as degradation kinetics of the outer layer were presented. Usability of the formed passive layer in clinical applications was evaluated through wear and corrosion tests of the femoral fixation model. The test results proved usefulness of the proposed surface modification methods for clinical application of different size and shape implants

Antibacterial iodine-supported titanium implants.

Science.gov (United States)

Shirai, T; Shimizu, T; Ohtani, K; Zen, Y; Takaya, M; Tsuchiya, H

2011-04-01

Deep infection remains a serious complication in orthopedic implant surgery. In order to reduce the incidence of implant-associated infections, several biomaterial surface treatments have been proposed. This study focused on evaluating the antibacterial activity of iodine-supported titanium (Ti-I(2)) and its impact on post-implant infection, as well as determining the potential suitability of Ti-I(2) as a biomaterial. External fixation pins were used in this experiment as trial implants because of the ease of making the septic models. The antibacterial activity of the metal was measured using a modification of the Japanese Industrial Standards method. Activity was evaluated by exposing the implants to Staphylococcus aureus or Escherichia coli and comparing reaction of pathogens to Ti-I(2) vs. stainless steel and titanium controls. Ti-I(2) clearly inhibited bacterial colonization more than the control metals. In addition, cytocompatibility was assessed by counting the number of colonies that formed on the metals. The three metals showed the same amount of fibroblast colony formation. Japanese white rabbits were used as an in vivo model. Three pins were inserted into both femora of six rabbits for histological analysis. Pin sites were inspected and graded for infection and inflammation. Fewer signs of infection and inflammatory changes were observed in conjunction with the Ti-I(2) pins. Furthermore, osteoconductivity of the implant was evaluated with osteoid formation surface of the pin. Consecutive bone formation was observed around the Ti-I(2) and titanium pins, while little osteoid formation was found around the stainless steel pins. These findings suggest that Ti-I(2) has antimicrobial activity and exhibits cytocompatibility. Therefore, Ti-I(2) substantially reduces the incidence of implant infection and shows particular promise as a biomaterial. Copyright © 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

In Vivo Evaluation of Immediately Loaded Stainless Steel and Titanium Orthodontic Screws in a Growing Bone

OpenAIRE

Gritsch, Kerstin; Laroche, Norbert; Bonnet, Jeanne-Marie; Exbrayat, Patrick; Morgon, Laurent; Rabilloud, Muriel; Grosgogeat, Brigitte

2013-01-01

The present work intends to evaluate the use of immediate loaded orthodontic screws in a growing model, and to study the specific bone response. Thirty-two screws (half of stainless steel and half of titanium) were inserted in the alveolar bone of 8 growing pigs. The devices were immediately loaded with a 100 g orthodontic force. Two loading periods were assessed: 4 and 12 weeks. Both systems of screws were clinically assessed. Histological observations and histomorphometric analysis evaluate...

Surface modification of titanium and titanium alloys by ion implantation.

Science.gov (United States)

Rautray, Tapash R; Narayanan, R; Kwon, Tae-Yub; Kim, Kyo-Han

2010-05-01

Titanium and titanium alloys are widely used in biomedical devices and components, especially as hard tissue replacements as well as in cardiac and cardiovascular applications, because of their desirable properties, such as relatively low modulus, good fatigue strength, formability, machinability, corrosion resistance, and biocompatibility. However, titanium and its alloys cannot meet all of the clinical requirements. Therefore, to improve the biological, chemical, and mechanical properties, surface modification is often performed. In view of this, the current review casts new light on surface modification of titanium and titanium alloys by ion beam implantation. (c) 2010 Wiley Periodicals, Inc.

The biocompatibility of SLA-treated titanium implants

International Nuclear Information System (INIS)

Kim, Hyeongil; Choi, Seong-Ho; Ryu, Jae-Jun; Koh, Seung-Yong; Park, Ju-Han; Lee, In-Seop

2008-01-01

The titanium implant surface was sandblasted with large grits and acid etched (SLA) to increase the implant surface for osseointegration. The topography of the titanium surface was investigated with scanning electron microscopy (SEM) and a profilometer. The SLA implant demonstrated uniform small micro pits (1-2 μm in diameter). The values of average roughness (R a ) and maximum height (R t ) were 1.19 μm and 10.53 μm respectively after sandblasting and the acid-etching treatment. In the cell-surface interaction study, the human osteoblast cells grew well in vitro. The in vivo evaluation of the SLA implant placed in rabbit tibia showed good bone-to-implant contact (BIC) with a mean value of 29% in total length of the implant. In the short-term clinical study, SLA implants demonstrated good clinical performance, maintaining good crestal bone height

Effect of mixed alloy combinations on fretting corrosion performance of spinal screw and rod implants.

Science.gov (United States)

Mali, Sachin A; Singh, Vaneet; Gilbert, Jeremy L

2017-07-01

Spinal implants are made from a variety of materials to meet the unique mechanical demands of each application. However, the medical device community has raised concern about mixing dissimilar metals in an implant because of fear of inducing corrosion. There is a lack of systematic studies on the effects of mixing metals on performance of spinal implants, especially in fretting corrosion conditions. Hence, the goal was to determine whether mixing stainless steel (SS316L), titanium alloy (Ti6Al4V) and cobalt chromium (CoCrMo) alloy components in a spinal implant leads to any increased risk of corrosion degradation. Spinal constructs consisting of single assembly screw-connector-rod components were tested using a novel short-term cyclic fretting corrosion test method. A total of 17 alloy component combinations (comprised of SS316L, Ti6Al4V-anodized and CoCrMo alloy for rod, screws and connectors) were tested under three anatomic orientations. Spinal constructs having all SS316L were most susceptible to fretting-initiated crevice corrosion attack and showed higher average fretting currents (∼25 - 30 µA), whereas constructs containing all Ti6Al4V components were less susceptible to fretting corrosion with average fretting currents in the range of 1 - 6 µA. Mixed groups showed evidence of fretting corrosion but they were not as severe as all SS316L group. SEM results showed evidence of severe corrosion attack in constructs having SS316L components. There also did not appear to be any galvanic effects of combining alloys together. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1169-1177, 2017. © 2016 Wiley Periodicals, Inc.

Osseointegration and biocompatibility of different metal implants - a comparative experimental investigation in sheep

Science.gov (United States)

2012-01-01

Background In the present study, 4 different metallic implant materials, either partly coated or polished, were tested for their osseointegration and biocompatibility in a pelvic implantation model in sheep. Methods Materials to be evaluated were: Cobalt-Chrome (CC), Cobalt-Chrome/Titanium coating (CCTC), Cobalt-Chrome/Zirconium/Titanium coating (CCZTC), Pure Titanium Standard (PTST), Steel, TAN Standard (TANST) and TAN new finish (TANNEW). Surgery was performed on 7 sheep, with 18 implants per sheep, for a total of 63 implants. After 8 weeks, the specimens were harvested and evaluated macroscopically, radiologically, biomechanically (removal torque), histomorphometrically and histologically. Results Cobalt-Chrome screws showed significantly (p = 0.031) lower removal torque values than pure titanium screws and also a tendency towards lower values compared to the other materials, except for steel. Steel screws showed no significant differences, in comparison to cobalt-chrome and TANST, however also a trend towards lower torque values than the remaining materials. The results of the fluorescence sections agreed with those of the biomechanical test. Histomorphometrically, there were no significant differences of bone area between the groups. The BIC (bone-to-implant-contact), used for the assessment of the osseointegration, was significantly lower for cobalt-chrome, compared to steel (p = 0.001). Steel again showed a lower ratio (p = 0.0001) compared to the other materials. Conclusion This study demonstrated that cobalt-chrome and steel show less osseointegration than the other metals and metal-alloys. However, osseointegration of cobalt-chrome was improved by zirconium and/or titanium based coatings (CCTC, TANST, TAN, TANNEW) being similar as pure titanium in their osseointegrative behavior. PMID:22400715

Influence of controlled immediate loading and implant design on peri-implant bone formation.

Science.gov (United States)

Vandamme, Katleen; Naert, Ignace; Geris, Liesbet; Vander Sloten, Jozef; Puers, Robert; Duyck, Joke

2007-02-01

Tissue formation at the implant interface is known to be sensitive to mechanical stimuli. The aim of the study was to compare the bone formation around immediately loaded versus unloaded implants in two different implant macro-designs. A repeated sampling bone chamber with a central implant was installed in the tibia of 10 rabbits. Highly controlled loading experiments were designed for a cylindrical (CL) and screw-shaped (SL) implant, while the unloaded screw-shaped (SU) implant served as a control. An F-statistic model with alpha=5% determined statistical significance. A significantly higher bone area fraction was observed for SL compared with SU (pimplant contact occurred was the highest for SL and significantly different from SU (pimplant contact was observed, a loading (SL versus SU: p=0.0049) as well as an implant geometry effect (SL versus CL: p=0.01) was found, in favour of the SL condition. Well-controlled immediate implant loading accelerates tissue mineralization at the interface. Adequate bone stimulation via mechanical coupling may account for the larger bone response around the screw-type implant compared with the cylindrical implant.

Clinical experiences with laser-welded titanium frameworks supported by implants in the edentulous mandible: a 10-year follow-up study.

Science.gov (United States)

Ortorp, Anders; Jemt, Torsten

2006-01-01

Long-term follow-up studies for more than 5 years are not available on laser-welded titanium frameworks. To report and compare 10-year data on implant-supported prostheses in the edentulous mandible provided with laser-welded titanium frameworks and conventional gold alloy frameworks. Altogether, 155 patients were consecutively treated with prostheses at abutment level with two generations of fixed laser-welded titanium frameworks (test groups). A control group of 53 randomly selected patients with conventional gold alloy castings was used for comparison. Clinical and radiographic 10-year data were collected for the three groups. All patients followed-up for 10 years (n=112) still had fixed prostheses in the mandible (cumulative success rate [CSR] 100%). The overall 10-year cumulative success rate (CSR) was 92.8 and 100.0% for titanium and gold alloy frameworks, respectively. Ten-year implant cumulative survival rate (CSR) was 99.4 and 99.6% for the test and control groups, respectively. Average 10-year bone loss was 0.56 (SD 0.45) mm for the titanium group and 0.77 (SD 0.36) mm for the control group (p screw components were below 3%. Excellent overall long-term results with 100% CSR could be achieved with the present treatment modality. Fractures of the metal frames and remade prostheses were more common for the laser-welded titanium frameworks, and the first generation of titanium frameworks worked poorly when compared with gold alloy frameworks during 10 years (p < 0.05). However, on average more bone loss was observed for implants supporting gold alloy frameworks during 10 years. The reasons for this difference are not clear.

Evaluation of Heat Transfer to the Implant-Bone Interface During Removal of Metal Copings Cemented onto Titanium Abutments.

Science.gov (United States)

Cakan, Umut; Cakan, Murat; Delilbasi, Cagri

2016-01-01

The aim of this investigation was to measure the temperature increase due to heat transferred to the implant-bone interface when the abutment screw channel is accessed or a metal-ceramic crown is sectioned buccally with diamond or tungsten carbide bur using an air rotor, with or without irrigation. Cobalt-chromium copings were cemented onto straight titanium abutments. The temperature changes during removal of the copings were recorded over a period of 1 minute. The sectioning of coping with diamond bur and without water irrigation generated the highest temperature change at the cervical part of the implant. Both crown removal methods resulted in an increase in temperature at the implant-bone interface. However, this temperature change did not exceed 47°C, the potentially damaging threshold for bone reported in the literature.

Mechanical stability of immediately loaded implants with various surfaces and designs: a pilot study in dogs.

Science.gov (United States)

Neugebauer, Jörg; Weinländer, Michael; Lekovic, Vojislav; von Berg, Karl-Heinz Linne; Zoeller, Joachim E

2009-01-01

Immediate loading is among the most innovative techniques in implant therapy today. This pilot study investigates the biomechanical outcome of various designs and surfaces that claim to shorten implant treatment. In each quadrant of two mongrel dogs, four different implants were used for immediate loading. The following implants were placed 3 months after tooth extraction: screw with low thread profile and anodic oxidized surface (LPAOS), solid screw with wide thread profile and titanium plasma spray coating (WPTPS), screw with low profile and hybrid design of double-etched and machined surface (LPHES), and screw with two thread profiles and a sandblasted and acid-etched surface (DTSAE). The insertion torque of each implant was above 35 Ncm. Resonance frequency analysis was performed after implant placement and again after sacrifice. Additionally, the removal torque and the amount of embedded titanium particles in the peri-implant bone were measured. All 16 prostheses were functional after a 5-month loading period. The highest mean removal torque values were recorded with WPTPS implants (24.4 Ncm/mm), followed by DTSAE implants (22.3 Ncm/mm) and LPAOS implants (18.7 Ncm/mm); the lowest score was obtained by LPHES (12.0 Ncm/mm). The ISQ values increased between the time of surgery and recall for all systems on average, but a significant positive correlation was found for DTSAE only. Significantly higher amounts of titanium were found in the surrounding bone with WPTPS (0.76%) and LPAOS (0.41%) in comparison with DTSAE (0.10%) and LPHES (0.03%). Immediate loading is possible with various designs and surfaces if high primary stability can be achieved during implant placement.

The influence of implant-abutment connection on the screw loosening and microleakage.

Science.gov (United States)

Tsuruta, Katsuhiro; Ayukawa, Yasunori; Matsuzaki, Tatsuya; Kihara, Masafumi; Koyano, Kiyoshi

2018-04-09

There are some spaces between abutment and implant body which can be a reservoir of toxic substance, and they can penetrate into subgingival space from microgap at the implant-abutment interface. This penetration may cause periimplantitis which is known to be one of the most important factors associated with late failure. In the present study, three kinds of abutment connection system, external parallel connection (EP), internal parallel connection (IP), and internal conical connection (CC), were studied from the viewpoint of microleakage from the gap between the implant and the abutment and in connection with the loosening of abutment screw. We observed dye leakage from abutment screw hole to outside through microgap under the excessive compressive and tensile load and evaluated the anti-leakage characteristics of these connection systems. During the experiment, one abutment screw for EP and two screws for IP, out of seven samples in each group, were fractured. After the 2000 cycles of compressive tensile loadings, removal torque value (RTV) of abutment screw represented no statistical differences among three groups. Standard deviation was largest in the RTV of EP and smallest in that of CC. The results of microleakage of toluidine blue from implant-abutment connection indicated that microleakage generally increased as loading procedure progressed. The amount of microleakage was almost plateau at 2000 cycles in CC, but still increasing in other two groups. The value of microleakage greatly scattered in EP, but the deviation of that in CC is significantly smaller. At 500 cycles of loading, there were no significant differences in the amount of microleakage among the groups, but at 1000, 1500, and 2000 cycles of loading, the amount of microleakage in CC was significantly smaller than that in IP. Throughout the experiment, the amount of microleakage in EP was largest, but no statistical difference was indicated due to the high standard deviation. Within the

Comparative effect of implant-abutment connections, abutment angulations, and screw lengths on preloaded abutment screw using three-dimensional finite element analysis: An in vitro study.

Science.gov (United States)

Kanneganti, Krishna Chaitanya; Vinnakota, Dileep Nag; Pottem, Srinivas Rao; Pulagam, Mahesh

2018-01-01

The purpose of this study is to compare the effect of implant-abutment connections, abutment angulations, and screw lengths on screw loosening (SL) of preloaded abutment using three dimensional (3D) finite element analysis. 3D models of implants (conical connection with hex/trilobed connections), abutments (straight/angulated), abutment screws (short/long), and crown and bone were designed using software Parametric Technology Corporation Creo and assembled to form 8 simulations. After discretization, the contact stresses developed for 150 N vertical and 100 N oblique load applications were analyzed, using ABAQUS. By assessing damage initiation and shortest fatigue load on screw threads, the SL for 2.5, 5, and 10 lakh cyclic loads were estimated, using fe-safe program. The obtained values were compared for influence of connection design, abutment angulation, and screw length. In straight abutment models, conical connection showed more damage (14.3%-72.3%) when compared to trilobe (10.1%-65.73%) at 2.5, 5, and 10 lakh cycles for both vertical and oblique loads, whereas in angulated abutments, trilobe (16.1%-76.9%) demonstrated more damage compared to conical (13.5%-70%). Irrespective of the connection type and abutment angulation, short screws showed more percentage of damage compared to long screws. The present study suggests selecting appropriate implant-abutment connection based on the abutment angulation, as well as preferring long screws with more number of threads for effective preload retention by the screws.

Chimeric Peptides as Implant Functionalization Agents for Titanium Alloy Implants with Antimicrobial Properties

Science.gov (United States)

Yucesoy, Deniz T.; Hnilova, Marketa; Boone, Kyle; Arnold, Paul M.; Snead, Malcolm L.; Tamerler, Candan

2015-04-01

Implant-associated infections can have severe effects on the longevity of implant devices and they also represent a major cause of implant failures. Treating these infections associated with implants by antibiotics is not always an effective strategy due to poor penetration rates of antibiotics into biofilms. Additionally, emerging antibiotic resistance poses serious concerns. There is an urge to develop effective antibacterial surfaces that prevent bacterial adhesion and proliferation. A novel class of bacterial therapeutic agents, known as antimicrobial peptides (AMPs), are receiving increasing attention as an unconventional option to treat septic infection, partly due to their capacity to stimulate innate immune responses and for the difficulty of microorganisms to develop resistance towards them. While host and bacterial cells compete in determining the ultimate fate of the implant, functionalization of implant surfaces with AMPs can shift the balance and prevent implant infections. In the present study, we developed a novel chimeric peptide to functionalize the implant material surface. The chimeric peptide simultaneously presents two functionalities, with one domain binding to a titanium alloy implant surface through a titanium-binding domain while the other domain displays an antimicrobial property. This approach gains strength through control over the bio-material interfaces, a property built upon molecular recognition and self-assembly through a titanium alloy binding domain in the chimeric peptide. The efficiency of chimeric peptide both in-solution and absorbed onto titanium alloy surface was evaluated in vitro against three common human host infectious bacteria, Streptococcus mutans, Staphylococcus epidermidis, and Escherichia coli. In biological interactions such as occur on implants, it is the surface and the interface that dictate the ultimate outcome. Controlling the implant surface by creating an interface composed chimeric peptides may therefore

Primary Stability of Zirconium vs Titanium Implants: An In Vitro Comparison

Science.gov (United States)

2015-06-05

of any copyrighted material in the thesis manuscript entitled: Primary Stability of Zirconium vs Titanium Implants: An In Vitro Comparison Is...Uniformed Services University Date: 02/20/2015 Primary Stability of Zirconium vs Titanium Implants: An In Vitro Comparison By...the thesis manuscript entitled: Primary Stability of Zirconium vs Titanium Implants: An In Vitro Comparison Is appropriately acknowledged

Influence of Screw Length and Bone Thickness on the Stability of Temporary Implants

Directory of Open Access Journals (Sweden)

Daniel Jogaib Fernandes

2015-09-01

Full Text Available The purpose of this work was to study the influence of screw length and bone thickness on the stability of temporary implants. A total of 96 self-drilling temporary screws with two different lengths were inserted into polyurethane blocks (n = 66, bovine femurs (n = 18 and rabbit tibia (n = 12 with different cortical thicknesses (1 to 8 mm. Screws insertion in polyurethane blocks was assisted by a universal testing machine, torque peaks were collected by a digital torquemeter and bone thickness was monitored by micro-CT. The results showed that the insertion torque was significantly increased with the thickness of cortical bone from polyurethane (p < 0.0001, bovine (p = 0.0035 and rabbit (p < 0.05 sources. Cancellous bone improved significantly the mechanical implant stability. Insertion torque and insertion strength was successfully moduled by equations, based on the cortical/cancellous bone behavior. Based on the results, insertion torque and bone strength can be estimate in order to prevent failure of the cortical layer during temporary screw placement. The stability provided by a cortical thickness of 2 or 1 mm coupled to cancellous bone was deemed sufficient for temporary implants stability.

The maintenance of inserted titanium implants: in-vitro evaluation of exposed surfaces cleaned with three different instruments.

Science.gov (United States)

Bertoldi, Carlo; Lusuardi, Donatella; Battarra, Francesca; Sassatelli, Paolo; Spinato, Sergio; Zaffe, Davide

2017-01-01

Changes to titanium implants smooth-surfaces after instrumentation were comparatively analyzed using low-vacuum scanning electron microscopy (LV-SEM) and white-light confocal (WLC) profilometry, to accurately evaluate curved surfaces. Sixty titanium implants screwed to their abutments were randomly split into three groups for cleaning treatment with (S) stainless-steel Gracey-curettes, (T) titanium Langer-curettes, and (P) an ultrasonic-device with the probe covered with a plastic-tip. One sector of each implant was left unprocessed (U). The other sectors were cleaned for either 60 s, to simulate a single cleaning session, or 180 s to simulate a series of sessions. Surface morphology was analyzed by LV-SEM, without metal sputtering. Quantitative evaluations of the roughness of surfaces were performed using a WLC-profilometer. The Wilcoxon and the Mann-Whitney tests were used in statistical comparisons. U-surfaces showed that thin transverse ridges and grooves, i.e. a polarized surface roughness was substantially compromised after S-instrumentation. Small surface alterations, increasing with time, were also recorded after T-·and·P-instrumentation, although to a lesser degree. The gap of the fixture-abutment connection appeared almost completely clean after T-, clotted with titanium debris after S-, and clotted with plastic debris after P-treatment. The mean roughness (Ra) was unchanged after P-, significantly increased after S- and decreased after T-treatment, when compared with U. The Rz roughness-parameter, calculated along the fixture Y-axis, of S, T, and P resulted similar and significantly lower than that of U. Rz (X-axis) resulted unchanged after P-, slightly increased (+40%) after T-, and greatly increased (+260%) after S-treatment, this latter being statistically significant when compared with U. The careful use of titanium-curettes could produce only minimal smooth surface alteration particularly over prolonged treatments, and avoid debris production

Comparison of titanium mesh implants with PLA-hydroxyapatite coatings for maxillofacial cancer reconstruction

Science.gov (United States)

Tverdokhlebov, S. I.; Choinzonov, E. L.; Kolokolova, O. V.; Cherdyntseva, N. V.

2016-08-01

Since 2013 physics of TPU and oncologists from the TCRI with participation of the "ConMet" company (Moscow) and the "Sintel" company (Tomsk Special Economic Zone resident) have been working on the theme entitled "Development of the composite implants for reconstructive surgery of a craniofacial areas of the traumatological and oncological patients" supported with the Federal Program "R&D, part 1.3". The goal was to develop the maxillo-facial implants on the basis of the transformable titanium mesh with PLA & hydroxyapatite coating. According to the Contract No. 14.578.21.0031, the team of developers had to start supplying these advanced implants to the industrial partners up to 2017. This research was supported with the preliminary market researches by the ISPMS SB RAS and the TP "MF". The stages of preliminary market researches were: 1) research of the Worldwide CMF market; 2) forecasting the BRIC CMF market up to 2020; 3) the total Russian market (epidemiology) estimation as a sum of official calculations and statistics; 4) looking for the best foreign analogue prices, comparing their and our implant properties; 5) search for the best Russian analogues; 6) the investigation of the world patent database Espacenet for the last years, and finding the owners and applicants of patents of CMF osteosynthesis plates on the basis of titanium coated with PLA & hydroxyapatite; 7) comparison of the domestic implants, and making conclusions. Several variants of the meshes have got the equal quality with the best foreign and Russian implants. The closest analogues were titanium, polyethylene, PEEK composite meshes suited to the patient shape by the Synthes company in 2014, and the only hybrid titanium "Grey" implant with layers of gelatin, dextran, collagen, HAP & BMP-2 was found. This implant was produced by Russian institution, and it was mentioned in the report on clinical trials by L.A. Pavlova et al., 2014 [1]. There are no manufacturers of the coated implants in Russia

In vitro assessment of artifacts induced by titanium, titanium-zirconium and zirconium dioxide implants in cone-beam computed tomography.

Science.gov (United States)

Sancho-Puchades, Manuel; Hämmerle, Christoph H F; Benic, Goran I

2015-10-01

The aim of this study was to test whether or not the intensity of artifacts around implants in cone-beam computed tomography (CBCT) differs between titanium, titanium-zirconium and zirconium dioxide implants. Twenty models of a human mandible, each containing one implant in the single-tooth gap position 45, were cast in dental stone. Five test models were produced for each of the following implant types: titanium 4.1 mm diameter (Ti4.1 ), titanium 3.3 mm diameter (Ti3.3 ), titanium-zirconium 3.3 mm diameter (TiZr3.3 ) and zirconium dioxide 3.5-4.5 mm diameter (ZrO3.5-4.5 ) implants. For control purposes, three models without implants were produced. Each model was scanned using a CBCT device. Gray values (GV) were recorded at eight circumferential positions around the implants at 0.5 mm, 1 mm and 2 mm from the implant surface (GVT est ). GV were assessed in the corresponding volumes of interest (VOI) in the control models without implants (GVC ontrol ). Differences of gray values (ΔGV) between GVT est and GVC ontrol were calculated as percentages. One-way ANOVA and post hoc tests were applied to detect differences between implant types. Mean ΔGV for ZrO3.5-4.5 presented the highest absolute values, generally followed by TiZr3.3 , Ti4.1 and Ti3.3 implants. The differences of ΔGV between ZrO3.5-4.5 and the remaining groups were statistically significant in the majority of the VOI (P ≤ 0.0167). ΔGV for TiZr3.3 , Ti4.1 and Ti3.3 implants did not differ significantly in the most VOI. For all implant types, ΔGV showed positive values buccally, mesio-buccally, lingually and disto-lingually, whereas negative values were detected mesially and distally. Zirconium dioxide implants generate significantly more artifacts as compared to titanium and titanium-zirconium implants. The intensity of artifacts around zirconium dioxide implants exhibited in average the threefold in comparison with titanium implants. © 2014 John Wiley & Sons A/S. Published by John Wiley

Nanotubular topography enhances the bioactivity of titanium implants.

Science.gov (United States)

Huang, Jingyan; Zhang, Xinchun; Yan, Wangxiang; Chen, Zhipei; Shuai, Xintao; Wang, Anxun; Wang, Yan

2017-08-01

Surface modification on titanium implants plays an important role in promoting mesenchymal stem cell (MSC) response to enhance osseointegration persistently. In this study, nano-scale TiO 2 nanotube topography (TNT), micro-scale sand blasted-acid etched topography (SLA), and hybrid sand blasted-acid etched/nanotube topography (SLA/TNT) were fabricated on the surfaces of titanium implants. Although the initial cell adherence at 60 min among TNT, SLA and TNT/SLA was not different, SLA and SLA/TNT presented to be rougher and suppressed the proliferation of MSC. TNT showed hydrophilic surface and balanced promotion of cellular functions. After being implanted in rabbit femur models, TNT displayed the best osteogenesis inducing ability as well as strong bonding strength to the substrate. These results indicate that nano-scale TNT provides favorable surface topography for improving the clinical performance of endosseous implants compared with micro and hybrid micro/nano surfaces, suggesting a promising and reliable surface modification strategy of titanium implants for clinical application. Copyright © 2017 Elsevier Inc. All rights reserved.

Corrosion of magnesium alloy AZ31 screws is dependent on the implantation site

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Willbold, E. [Laboratory for Biomechanics and Biomaterials, Department of Orthopaedic Surgery, Hannover Medical School, Anna-von-Borries-Strasse 1-7, D - 30625 Hannover (Germany); Kaya, A.A. [Mugla University, Engineering Faculty, Metallurgy and Materials Engineering Department, Mugla (Turkey); Kaya, R.A. [MedicalPark Hospital, Kueltuer Sok No:1, 34160 Bahcelievler, Istanbul (Turkey); Beckmann, F. [Helmholtz-Zentrum Geesthacht, Institute of Materials Research, Max-Planck-Str.1, D - 21502 Geesthacht (Germany); Witte, F., E-mail: witte.frank@mh-hannover.de [Laboratory for Biomechanics and Biomaterials, Department of Orthopaedic Surgery, Hannover Medical School, Anna-von-Borries-Strasse 1-7, D - 30625 Hannover (Germany)

2011-12-15

The corrosion of biodegradable materials is a crucial issue in implant development. Among other materials, magnesium and magnesium based alloys are one of the most promising candidates. Since the corrosion of biodegradable materials depends on different physiological parameters like pH or ion concentrations, the corrosion might be different in different biological environments. To investigate this issue, we produced screws from magnesium alloy AZ31 and implanted them into the hip bone of 14 sheep. After 3 and 6 months, the screws were explanted and analyzed with synchrotron-radiation based micro-computed tomography and hard tissue histology. We found considerable differences in the corrosion behavior of the magnesium screws with respect to its original tissue location. However, we could detect a normal immunological tissue response.

Laser-Modified Surface Enhances Osseointegration and Biomechanical Anchorage of Commercially Pure Titanium Implants for Bone-Anchored Hearing Systems

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Omar, Omar; Simonsson, Hanna; Palmquist, Anders; Thomsen, Peter

2016-01-01

Osseointegrated implants inserted in the temporal bone are a vital component of bone-anchored hearing systems (BAHS). Despite low implant failure levels, early loading protocols and simplified procedures necessitate the application of implants which promote bone formation, bone bonding and biomechanical stability. Here, screw-shaped, commercially pure titanium implants were selectively laser ablated within the thread valley using an Nd:YAG laser to produce a microtopography with a superimposed nanotexture and a thickened surface oxide layer. State-of-the-art machined implants served as controls. After eight weeks’ implantation in rabbit tibiae, resonance frequency analysis (RFA) values increased from insertion to retrieval for both implant types, while removal torque (RTQ) measurements showed 153% higher biomechanical anchorage of the laser-modified implants. Comparably high bone area (BA) and bone-implant contact (BIC) were recorded for both implant types but with distinctly different failure patterns following biomechanical testing. Fracture lines appeared within the bone ~30–50 μm from the laser-modified surface, while separation occurred at the bone-implant interface for the machined surface. Strong correlations were found between RTQ and BIC and between RFA at retrieval and BA. In the endosteal threads, where all the bone had formed de novo, the extracellular matrix composition, the mineralised bone area and osteocyte densities were comparable for the two types of implant. Using resin cast etching, osteocyte canaliculi were observed directly approaching the laser-modified implant surface. Transmission electron microscopy showed canaliculi in close proximity to the laser-modified surface, in addition to a highly ordered arrangement of collagen fibrils aligned parallel to the implant surface contour. It is concluded that the physico-chemical surface properties of laser-modified surfaces (thicker oxide, micro- and nanoscale texture) promote bone bonding

Effectiveness of transfixation and length of instrumentation on titanium and stainless steel transpedicular spine implants.

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Korovessis, P; Baikousis, A; Deligianni, D; Mysirlis, Y; Soucacos, P

2001-04-01

This study compares the effectiveness of transfixation on the stiffness of two pedicle screw-rod constructs of different manufacture, implant design, and alloy, applied in one-and two-level instability. Four screws composed of either stainless steel or Titanium were assembled in pairs to two polymethylmethacrylate blocks to resemble one-and two-level corpectomy models and the construct underwent nondestructive torsional, extension, and flexion loading. In every loading test, each construct was tested using stainless steel or titanium rods of 4.9-mm diameter in two different lengths (short, 10 cm; long, 15 cm), not augmented or augmented with different transfixation devices or a pair of devices. The authors compared the stiffness of stainless steel and titanium constructs without cross-link with the stiffness of that reinforced with single or double Texas Scottish Rite Hospital (TSRH) cross-link, closed new-type cross-link (closed NTC), or open new-type cross-link (open NTC). The results showed that augmentation or no augmentation of short rods conferred significantly more stiffness than that of long rods of the same material in all three loading modes. The closed NTC provided the greatest increase of torsional, extension, and flexion stiffness, and single TSRH provided the least amount of stiffness. Torsional stiffness of short stainless steel rods augmented or not augmented was significantly greater than that of their titanium counterparts. Torsional stiffness of long titanium rods was always greater than that of their stainless steel counterparts. Extension stiffness of short nonaugmented titanium rods was superior to that of long titanium rods, whereas extension stiffness of nonaugmented short and long stainless steel rods was similar. Nonaugmented short titanium rods showed greater flexion stiffness than that of long titanium rods. Long stainless steel rods displayed significantly greater flexion stiffness than did their titanium counterparts. This

Cannulated screw and cable are superior to modified tension band in the treatment of transverse patella fractures.

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Tian, Yun; Zhou, Fang; Ji, Hongquan; Zhang, Zhishan; Guo, Yan

2011-12-01

Although the modified tension band technique (eg, tension band supplemented by longitudinal Kirschner wires) has long been the mainstay for fixation of transverse fractures of the patella, it has shortcomings, such as bad reduction, loosening of implants, and skin irritation. We conducted a retrospective comparison of the modified tension band technique and the titanium cable-cannulated screw tension band technique. We retrospectively reviewed 101 patients aged 22 to 85 years (mean, 56.6 years) with AO/OTA 34-C1 fractures (n = 68) and 34-C2 fractures (n = 33). Fifty-two patients were in the modified tension band group and 49 were in the titanium cable-cannulated screw tension band group. Followup was at least 1 year (range, 1-3 years). Comparison criteria were fracture reduction, fracture healing time, and the Iowa score for knee function. The titanium cable-cannulated screw tension band group showed improved fracture reduction, reduced healing time, and better Iowa score, compared with the modified tension band group. In the modified tension band group, eight patients experienced wire migration, three of these requiring a second operation. There were no complications in the titanium cable-cannulated screw tension band group. The titanium cable-cannulated screw tension band technique showed superior results and should be considered as an alternative method for treatment of transverse patellar fractures. Level III, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Influence of different tightening forces before laser welding to the implant/framework fit.

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da Silveira-Júnior, Clebio Domingues; Neves, Flávio Domingues; Fernandes-Neto, Alfredo Júlio; Prado, Célio Jesus; Simamoto-Júnior, Paulo César

2009-06-01

The aim of the present study was to evaluate the influence of abutment screw tightening force before laser welding procedures on the vertical fit of metal frameworks over four implants. To construct the frameworks, prefabricated titanium abutments and cylindrical titanium bars were joined by laser welding to compose three groups: group of manual torque (GMT), GT10 and GT20. Before welding, manual torque simulating routine laboratory procedure was applied to GTM. In GT10 and GT20, the abutment screws received 10 and 20 Ncm torque, respectively. After welding, the implant/framework interfaces were assessed by optical comparator microscope using two methods. First, the single screw test (SST) was used, in which the interfaces of the screwed and non-screwed abutments were assessed, considering only the abutments at the framework extremities. Second, the interfaces of all the abutments were evaluated when they were screwed. In the SST, intergroup analysis (Kruskal Wallis) showed no significant difference among the three conditions of tightening force; that is, the different tightening force before welding did not guarantee smaller distortions. Intragroup analysis (Wilcoxon) showed that for all groups, the interfaces of the non-screwed abutments were statistically greater than the interfaces of the screwed abutments, evidencing distortions in all the frameworks. ANOVA was applied for the comparison of interfaces when all the abutments were screwed and showed no significant difference among the groups. Under the conditions of this study, pre-welding tightness on abutment screws did not influence the vertical fit of implant-supported metal frameworks.

Probabilistic analysis of preload in the abutment screw of a dental implant complex.

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Guda, Teja; Ross, Thomas A; Lang, Lisa A; Millwater, Harry R

2008-09-01

Screw loosening is a problem for a percentage of implants. A probabilistic analysis to determine the cumulative probability distribution of the preload, the probability of obtaining an optimal preload, and the probabilistic sensitivities identifying important variables is lacking. The purpose of this study was to examine the inherent variability of material properties, surface interactions, and applied torque in an implant system to determine the probability of obtaining desired preload values and to identify the significant variables that affect the preload. Using software programs, an abutment screw was subjected to a tightening torque and the preload was determined from finite element (FE) analysis. The FE model was integrated with probabilistic analysis software. Two probabilistic analysis methods (advanced mean value and Monte Carlo sampling) were applied to determine the cumulative distribution function (CDF) of preload. The coefficient of friction, elastic moduli, Poisson's ratios, and applied torque were modeled as random variables and defined by probability distributions. Separate probability distributions were determined for the coefficient of friction in well-lubricated and dry environments. The probabilistic analyses were performed and the cumulative distribution of preload was determined for each environment. A distinct difference was seen between the preload probability distributions generated in a dry environment (normal distribution, mean (SD): 347 (61.9) N) compared to a well-lubricated environment (normal distribution, mean (SD): 616 (92.2) N). The probability of obtaining a preload value within the target range was approximately 54% for the well-lubricated environment and only 0.02% for the dry environment. The preload is predominately affected by the applied torque and coefficient of friction between the screw threads and implant bore at lower and middle values of the preload CDF, and by the applied torque and the elastic modulus of the abutment

Silicon-Doped Titanium Dioxide Nanotubes Promoted Bone Formation on Titanium Implants.

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Zhao, Xijiang; Wang, Tao; Qian, Shi; Liu, Xuanyong; Sun, Junying; Li, Bin

2016-02-26

While titanium (Ti) implants have been extensively used in orthopaedic and dental applications, the intrinsic bioinertness of untreated Ti surface usually results in insufficient osseointegration irrespective of the excellent biocompatibility and mechanical properties of it. In this study, we prepared surface modified Ti substrates in which silicon (Si) was doped into the titanium dioxide (TiO₂) nanotubes on Ti surface using plasma immersion ion implantation (PIII) technology. Compared to TiO₂ nanotubes and Ti alone, Si-doped TiO₂ nanotubes significantly enhanced the expression of genes related to osteogenic differentiation, including Col-I, ALP, Runx2, OCN, and OPN, in mouse pre-osteoblastic MC3T3-E1 cells and deposition of mineral matrix. In vivo, the pull-out mechanical tests after two weeks of implantation in rat femur showed that Si-doped TiO₂ nanotubes improved implant fixation strength by 18% and 54% compared to TiO₂-NT and Ti implants, respectively. Together, findings from this study indicate that Si-doped TiO₂ nanotubes promoted the osteogenic differentiation of osteoblastic cells and improved bone-Ti integration. Therefore, they may have considerable potential for the bioactive surface modification of Ti implants.

Strength of titanium intramedullary implant versus miniplate fixation of mandibular condyle fractures.

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Frake, Paul C; Howell, Rebecca J; Joshi, Arjun S

2012-07-01

To test the strength of internal fixation of mandibular condyle fractures repaired with titanium miniplates versus titanium intramedullary implants. Prospective laboratory experimentation in urethane mandible models and human cadaveric mandibles. Materials testing laboratory at an academic medical center. Osteotomies of the mandibular condyle were created in 40 urethane hemimandible models and 24 human cadaveric specimens. Half of the samples in each group were repaired with traditional miniplates, and the other half were repaired with intramedullary titanium implants. Anteroposterior and mediolateral loads were applied to the samples, and the displacement was measured with reference to the applied force. Titanium intramedullary implants demonstrated statistically significant improved strength and stiffness versus miniplates in the urethane model experimental groups. Despite frequent plastic deformation and mechanical failures of the miniplates, a 1.6-mm-diameter titanium intramedullary pin did not mechanically fail in any of the cases. Intramedullary implantation failures were due to secondary fracture of the adjacent cortical bone or experimental design limitations including rotation of the smooth pin implant. Mechanical implant failures that were encountered with miniplate fixation were not seen with titanium intramedullary implants. These intramedullary implants provide stronger and more rigid fixation of mandibular condyle fractures than miniplates in this in vitro model.

Distortion of CAD-CAM-fabricated implant-fixed titanium and zirconia complete dental prosthesis frameworks.

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Al-Meraikhi, Hadi; Yilmaz, Burak; McGlumphy, Edwin; Brantley, William A; Johnston, William M

2018-01-01

Computer-aided design and computer-aided manufacturing (CAD-CAM)-fabricated titanium and zirconia implant-supported fixed dental prostheses have become increasingly popular for restoring patients with complete edentulism. However, the distortion level of these frameworks is not well known. The purpose of this in vitro study was to compare the 3-dimensional (3D) distortion of CAD-CAM zirconia and titanium implant-fixed screw-retained complete dental prostheses. A master edentulous model with 4 implants at the positions of the maxillary first molars and canines was used. Multiunit abutments (Nobel Biocare) secured to the model were digitally scanned using scan bodies and a laboratory scanner (S600 ARTI; Zirkonzahn). Titanium (n=5) and zirconia (n=5) frameworks were milled using a CAD-CAM system (Zirkonzahn M1; Zirkonzahn). All frameworks were scanned using an industrial computed tomography (CT) scanner (Nikon/X-Tek XT H 225kV MCT Micro-Focus). The direct CT scans were reconstructed to generate standard tessellation language (STL) files. To calculate the 3D distortion of the frameworks, STL files of the CT scans were aligned to the CAD model using a sum of the least squares best-fit algorithm. Surface comparison points were placed on the CAD model on the midfacial aspect of all teeth. The 3D distortion of each direct scan to the CAD model was calculated. In addition, color maps of the scan-to-CAD comparison were constructed using a ±0.500 mm color scale range. Both materials exhibited distortion; however, no significant difference was found in the amount of distortion from the CAD model between the materials (P=.747). Absolute values of deviations from the CAD model were evident in the x and y plane and less so in the z direction. Zirconia and titanium frameworks showed similar 3D distortion compared with the CAD model for the tested CAD-CAM and implant systems. The distortion was more pronounced in the horizontal and sagittal plane than in the vertical plane

Bone integration capability of nanopolymorphic crystalline hydroxyapatite coated on titanium implants

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Suzuki T

2012-02-01

Full Text Available Masahiro Yamada*, Takeshi Ueno*, Naoki Tsukimura, Takayuki Ikeda, Kaori Nakagawa, Norio Hori, Takeo Suzuki, Takahiro OgawaLaboratory of Bone and Implant Sciences, The Weintraub Center for Reconstructive Biotechnology, Division of Advanced Prosthodontics, Biomaterials and Hospital Dentistry, UCLA School of Dentistry, Los Angeles, CA, USA *These authors contributed equally to this workAbstract: The mechanism by which hydroxyapatite (HA-coated titanium promotes bone–implant integration is largely unknown. Furthermore, refining the fabrication of nanostructured HA to the level applicable to the mass production process for titanium implants is challenging. This study reports successful creation of nanopolymorphic crystalline HA on microroughened titanium surfaces using a combination of flame spray and low-temperature calcination and tests its biological capability to enhance bone–implant integration. Sandblasted microroughened titanium implants and sandblasted + HA-coated titanium implants were subjected to biomechanical and histomorphometric analyses in a rat model. The HA was 55% crystallized and consisted of nanoscale needle-like architectures developed in various diameters, lengths, and orientations, which resulted in a 70% increase in surface area compared to noncoated microroughened surfaces. The HA was free from impurity contaminants, with a calcium/phosphorus ratio of 1.66 being equivalent to that of stoichiometric HA. As compared to microroughened implants, HA-coated implants increased the strength of bone–implant integration consistently at both early and late stages of healing. HA-coated implants showed an increased percentage of bone–implant contact and bone volume within 50 µm proximity of the implant surface, as well as a remarkably reduced percentage of soft tissue intervention between bone and the implant surface. In contrast, bone volume outside the 50 µm border was lower around HA-coated implants. Thus, this study

Comparative effect of implant-abutment connections, abutment angulations, and screw lengths on preloaded abutment screw using three-dimensional finite element analysis: An in vitro study

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Krishna Chaitanya Kanneganti

2018-01-01

Conclusions: The present study suggests selecting appropriate implant-abutment connection based on the abutment angulation, as well as preferring long screws with more number of threads for effective preload retention by the screws.

Long-term hearing result using Kurz titanium ossicular implants.

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Hess-Erga, Jeanette; Møller, Per; Vassbotn, Flemming Slinning

2013-05-01

Titanium implants in middle ear surgery were introduced in the late 90s and are now frequently used in middle ear surgery. However, long-term studies of patient outcome are few and have only been published in subgroups of patients. We report the long-term effect of titanium middle ear implants for ossicular reconstruction in chronic ear disease investigated in a Norwegian tertiary otological referral centre. Retrospective chart reviews were performed for procedures involving 76 titanium implants between 2000 and 2007. All patients who underwent surgery using the Kurz Vario titanium implant were included in the study. Audiological parameters using four frequencies, 0.5, 1, 2, and 3 kHz, according to AAO-HNS guidelines, was assessed pre and postoperatively. Otosurgical procedures, complications, revisions, and extrusion rates were analyzed. The study had no dropouts. The partial ossicular replacement prosthesis (PORP) was used in 44 procedures and the total ossicular replacement prosthesis (TORP) in 32 procedures, respectively. Mean follow-up was 5.2 years (62 months). The ossiculoplasties were performed as staging procedures or in combination with other chronic ear surgery. The same surgeon performed all the procedures. A postoperative air-bone gap of ≤ 20 dB was obtained in 74 % of the patients, 82 % for the Bell (PORP) prosthesis, and 63 % for the Arial (TORP) prosthesis. The extrusion rate was 5 %. We conclude that titanium ossicular implants give stable and excellent long-term hearing results.

Antimicrobial and Osseointegration Properties of Nanostructured Titanium Orthopaedic Implants.

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Jäger, Marcus; Jennissen, Herbert P; Dittrich, Florian; Fischer, Alfons; Köhling, Hedda Luise

2017-11-13

The surface design of titanium implants influences not only the local biological reactions but also affects at least the clinical result in orthopaedic application. During the last decades, strong efforts have been made to improve osteointegration and prevent bacterial adhesion to these surfaces. Following the rule of "smaller, faster, cheaper", nanotechnology has encountered clinical application. It is evident that the hierarchical implant surface micro- and nanotopography orchestrate the biological cascades of early peri-implant endosseous healing or implant loosening. This review of the literature gives a brief overview of nanostructured titanium-base biomaterials designed to improve osteointegration and prevent from bacterial infection.

High-intensity low energy titanium ion implantation into zirconium alloy

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Ryabchikov, A. I.; Kashkarov, E. B.; Pushilina, N. S.; Syrtanov, M. S.; Shevelev, A. E.; Korneva, O. S.; Sutygina, A. N.; Lider, A. M.

2018-05-01

This research describes the possibility of ultra-high dose deep titanium ion implantation for surface modification of zirconium alloy Zr-1Nb. The developed method based on repetitively pulsed high intensity low energy titanium ion implantation was used to modify the surface layer. The DC vacuum arc source was used to produce metal plasma. Plasma immersion titanium ions extraction and their ballistic focusing in equipotential space of biased electrode were used to produce high intensity titanium ion beam with the amplitude of 0.5 A at the ion current density 120 and 170 mA/cm2. The solar eclipse effect was used to prevent vacuum arc titanium macroparticles from appearing in the implantation area of Zr sample. Titanium low energy (mean ion energy E = 3 keV) ions were implanted into zirconium alloy with the dose in the range of (5.4-9.56) × 1020 ion/cm2. The effect of ion current density, implantation dose on the phase composition, microstructure and distribution of elements was studied by X-ray diffraction, scanning electron microscopy and glow-discharge optical emission spectroscopy, respectively. The results show the appearance of Zr-Ti intermetallic phases of different stoichiometry after Ti implantation. The intermetallic phases are transformed from both Zr0.7Ti0.3 and Zr0.5Ti0.5 to single Zr0.6Ti0.4 phase with the increase in the implantation dose. The changes in phase composition are attributed to Ti dissolution in zirconium lattice accompanied by the lattice distortions and appearance of macrostrains in intermetallic phases. The depth of Ti penetration into the bulk of Zr increases from 6 to 13 μm with the implantation dose. The hardness and wear resistance of the Ti-implanted zirconium alloy were increased by 1.5 and 1.4 times, respectively. The higher current density (170 mA/cm2) leads to the increase in the grain size and surface roughness negatively affecting the tribological properties of the alloy.

Titanium diffusion in shinbone of rats with osseointegrated implants.

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Grenón, Miriam S; Robledo, José; Ibáñez, Juan Carlos; Sánchez, Héctor J

2016-11-01

Dental implants are composed of commercially pure Ti (which is actually an alloy of titanium, and minor or trace components such as aluminium and vanadium). When the implant is inserted, its surface undergoes a number of chemical and mechanical processes, releasing particles of titanium to the medium. The metabolism of free ions of titanium is uncertain; the uptaking processes in the body are not well known, nor their toxic dose. In addition, physical properties of newly formed bone, such as diffusivity and activation energy, are scarce and rarely studied. In this study, we analysed the diffusion of titanium in the titanium-implanted shinbones of six adult male Wistar rats by spatially resolved micro x-ray fluorescence. The measurements were carried out at the microfluorescence station of the x-ray fluorescence (XRF) beamline of the Brazilian synchrotron facility LNLS (from Portuguese 'Laboratorio Nacional de Luz Sincrotron'). For each sample, XRF spectra were taken by linear scanning in area near the new bone formed around the Ti implant. The scanning line shows a clear effect of titanium diffusion whereas calcium intensity presents a different behaviour. Moreover, a clear correlation among the different structures of bones is observed in the Ti and Ca intensities. The results obtained in these measurements may allow determining quantitatively the parameters of diffusion rates and other physical properties of new bone like diffusion coefficients. © 2016 The Authors Journal of Microscopy © 2016 Royal Microscopical Society.

Histomorphometric and histologic evaluation of titanium-zirconium (aTiZr) implants with anodized surfaces.

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Sharma, Ajay; McQuillan, A James; Shibata, Yo; Sharma, Lavanya A; Waddell, John Neil; Duncan, Warwick John

2016-05-01

The choice of implant surface has a significant influence on osseointegration. Modification of TiZr surface by anodization is reported to have the potential to modulate the osteoblast cell behaviour favouring more rapid bone formation. The aim of this study is to investigate the effect of anodizing the surface of TiZr discs with respect to osseointegration after four weeks implantation in sheep femurs. Titanium (Ti) and TiZr discs were anodized in an electrolyte containing DL-α-glycerophosphate and calcium acetate at 300 V. The surface characteristics were analyzed by scanning electron microscopy, electron dispersive spectroscopy, atomic force microscopy and goniometry. Forty implant discs with thickness of 1.5 and 10 mm diameter (10 of each-titanium, titanium-zirconium, anodized titanium and anodized titanium-zirconium) were placed in the femoral condyles of 10 sheep. Histomorphometric and histologic analysis were performed 4 weeks after implantation. The anodized implants displayed hydrophilic, porous, nano-to-micrometer scale roughened surfaces. Energy dispersive spectroscopy analysis revealed calcium and phosphorous incorporation into the surface of both titanium and titanium-zirconium after anodization. Histologically there was new bone apposition on all implanted discs, slightly more pronounced on anodised discs. The percentage bone-to-implant contact measurements of anodized implants were higher than machined/unmodified implants but there was no significant difference between the two groups with anodized surfaces (P > 0.05, n = 10). The present histomorphometric and histological findings confirm that surface modification of titanium-zirconium by anodization is similar to anodised titanium enhances early osseointegration compared to machined implant surfaces.

Evaluation of Osseointegration of Titanium Alloyed Implants Modified by Plasma Polymerization

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Carolin Gabler

2014-02-01

Full Text Available By means of plasma polymerization, positively charged, nanometre-thin coatings can be applied to implant surfaces. The aim of the present study was to quantify the adhesion of human bone cells in vitro and to evaluate the bone ongrowth in vivo, on titanium surfaces modified by plasma polymer coatings. Different implant surface configurations were examined: titanium alloy (Ti6Al4V coated with plasma-polymerized allylamine (PPAAm and plasma-polymerized ethylenediamine (PPEDA versus uncoated. Shear stress on human osteoblast-like MG-63 cells was investigated in vitro using a spinning disc device. Furthermore, bone-to-implant contact (BIC was evaluated in vivo. Custom-made conical titanium implants were inserted at the medial tibia of female Sprague-Dawley rats. After a follow-up of six weeks, the BIC was determined by means of histomorphometry. The quantification of cell adhesion showed a significantly higher shear stress for MG-63 cells on PPAAm and PPEDA compared to uncoated Ti6Al4V. Uncoated titanium alloyed implants showed the lowest BIC (40.4%. Implants with PPAAm coating revealed a clear but not significant increase of the BIC (58.5% and implants with PPEDA a significantly increased BIC (63.7%. In conclusion, plasma polymer coatings demonstrate enhanced cell adhesion and bone ongrowth compared to uncoated titanium surfaces.

Comparison of two systems for rigidly connecting 2.0-mm bone screws to an implantable device : in vitro stability testing

NARCIS (Netherlands)

van Loon, JP; de Bont, LGM; Verkerke, GJ

The stability of a screw-fixed implantable device can be improved by eliminating the freedom of movement between the screws and the device. Two systems have been developed for rigidly connecting 2.0-mm bone screws to an implantable device, and the aim of this study was to test and compare the

Influence of Diamondlike Carbon Coating of Screws on Axial Tightening Force and Stress Distribution on Overdenture Bar Frameworks with Different Fit Levels and Materials.

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dos Santos, Mateus Bertolini Fernandes; Bacchi, Atais; Consani, Rafael Leonardo Xediek; Correr-Sobrinho, Lourenço

2015-01-01

The aim of this study was to evaluate the axial tightening force applied by conventional and diamondlike carbon (DLC)-coated screws and to verify, through three-dimensional finite element analysis (FEA), the stress distribution caused by different framework materials and prosthetic screws in overdenture frameworks with different misfit levels. The axial tightening force applied by the screw was evaluated by means of a titanium matrix connected to a load cell. Conventional titanium or DLC-coated screws were tightened with a digital torque wrench, and the load values were recorded. The values were applied in an FEA to a bar-clip attachment system connected to two 4.0 × 11-mm external-hexagon titanium implants placed in an anterior edentulous arch. DLC-coated and conventional screws were modeled with their respective axial forces obtained on the experimental evaluation for three bar framework materials (titanium, nickel-chromium, and cobalt-chromium) and three levels of misfit (100, 150, and 200 μm). Von Mises stresses for prosthetic components and maximum principal stress and microstrains (maximum principal strains) for bone tissue were measured. The mean force applied by the conventional screw was 25.55 N (± 1.78); the prosthetic screw coated with a DLC layer applied a mean force of 31.44 N (± 2.11), a statistically significant difference. In the FEA, the DLC screw led to higher stresses on the framework; however, the prosthetic screw suffered lower stress. No influence of screw type was seen in the bone tissue. Titanium frameworks reduced the stress transmitted to the bone tissue and the bar framework but had no influence on the screws. Higher misfit values resulted in an increased stress/strain in bone tissue and bar framework, which was not the case for retention screws.

Plasma-sprayed titanium coating to polyetheretherketone improves the bone-implant interface.

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Walsh, William R; Bertollo, Nicky; Christou, Chrisopher; Schaffner, Dominik; Mobbs, Ralph J

2015-05-01

Rapid and stable fixation at the bone-implant interface would be regarded as one of the primary goals to achieve clinical efficacy, regardless of the surgical site. Although mechanical and physical properties of polyetheretherketone (PEEK) provide advantages for implant devices, the hydrophobic nature and the lack of direct bone contact remains a limitation. To examine the effects of a plasma-sprayed titanium coated PEEK on the mechanical and histologic properties at the bone-implant interface. A preclinical laboratory study. Polyetheretherketone and plasma-sprayed titanium coated PEEK implants (Ti-bond; Spinal Elements, Carlsbad, CA, USA) were placed in a line-to-line manner in cortical bone and in a press-fit manner in cancellous bone of adult sheep using an established ovine model. Shear strength was assessed in the cortical sites at 4 and 12 weeks, whereas histology was performed in cortical and cancellous sites at both time points. The titanium coating dramatically improved the shear strength at the bone-implant interface at 4 weeks and continued to improve with time compared with PEEK. Direct bone ongrowth in cancellous and cortical sites can be achieved using a plasma-sprayed titanium coating on PEEK. Direct bone to implant bonding can be achieved on PEEK in spite of its hydrophobic nature using a plasma-sprayed titanium coating. The plasma-sprayed titanium coating improved mechanical properties in the cortical sites and the histology in cortical and cancellous sites. Copyright © 2015 Elsevier Inc. All rights reserved.

Effect of pore size on bone ingrowth into porous titanium implants fabricated by additive manufacturing: An in vivo experiment

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Taniguchi, Naoya, E-mail: tani110@kuhp.kyoto-u.ac.jp [Department of Orthopaedic Surgery, Kyoto University Graduate School of Medicine, 54 Kawahara-cho, Shogoin, Sakyo, Kyoto 606-8507 (Japan); Fujibayashi, Shunsuke, E-mail: shfuji@kuhp.kyoto-u.ac.jp [Department of Orthopaedic Surgery, Kyoto University Graduate School of Medicine, 54 Kawahara-cho, Shogoin, Sakyo, Kyoto 606-8507 (Japan); Takemoto, Mitsuru, E-mail: m.take@kuhp.kyoto-u.ac.jp [Department of Orthopaedic Surgery, Kyoto University Graduate School of Medicine, 54 Kawahara-cho, Shogoin, Sakyo, Kyoto 606-8507 (Japan); Sasaki, Kiyoyuki, E-mail: kiy-sasaki@spcom.co.jp [Sagawa Printing Co., Ltd., 5-3, Inui, Morimoto-Cho, Mukou-Shi, Kyoto 617-8588 (Japan); Otsuki, Bungo, E-mail: bungo@kuhp.kyoto-u.ac.jp [Department of Orthopaedic Surgery, Kyoto University Graduate School of Medicine, 54 Kawahara-cho, Shogoin, Sakyo, Kyoto 606-8507 (Japan); Nakamura, Takashi, E-mail: ntaka@kuhp.kyoto-u.ac.jp [National Hospital Organization Kyoto Medical Center, 1-1, Mukaihatacho, Hukakusa, Hushimi, Kyoto 612-8555 (Japan); Matsushita, Tomiharu, E-mail: matsushi@isc.chubu.ac.jp [Department of Biomedical Sciences, College of Life and Health Sciences, Chubu University, 1200 Matsumoto-cho, Kasugai, Aichi 487-8501 (Japan); Kokubo, Tadashi, E-mail: kokubo@isc.chubu.ac.jp [Department of Biomedical Sciences, College of Life and Health Sciences, Chubu University, 1200 Matsumoto-cho, Kasugai, Aichi 487-8501 (Japan); Matsuda, Shuichi, E-mail: smat522@kuhp.kyoto-u.ac.jp [Department of Orthopaedic Surgery, Kyoto University Graduate School of Medicine, 54 Kawahara-cho, Shogoin, Sakyo, Kyoto 606-8507 (Japan)

2016-02-01

Selective laser melting (SLM) is an additive manufacturing technique with the ability to produce metallic scaffolds with accurately controlled pore size, porosity, and interconnectivity for orthopedic applications. However, the optimal pore structure of porous titanium manufactured by SLM remains unclear. In this study, we evaluated the effect of pore size with constant porosity on in vivo bone ingrowth in rabbits into porous titanium implants manufactured by SLM. Three porous titanium implants (with an intended porosity of 65% and pore sizes of 300, 600, and 900 μm, designated the P300, P600, and P900 implants, respectively) were manufactured by SLM. A diamond lattice was adapted as the basic structure. Their porous structures were evaluated and verified using microfocus X-ray computed tomography. Their bone–implant fixation ability was evaluated by their implantation as porous-surfaced titanium plates into the cortical bone of the rabbit tibia. Bone ingrowth was evaluated by their implantation as cylindrical porous titanium implants into the cancellous bone of the rabbit femur for 2, 4, and 8 weeks. The average pore sizes of the P300, P600, and P900 implants were 309, 632, and 956 μm, respectively. The P600 implant demonstrated a significantly higher fixation ability at 2 weeks than the other implants. After 4 weeks, all models had sufficiently high fixation ability in a detaching test. Bone ingrowth into the P300 implant was lower than into the other implants at 4 weeks. Because of its appropriate mechanical strength, high fixation ability, and rapid bone ingrowth, our results indicate that the pore structure of the P600 implant is a suitable porous structure for orthopedic implants manufactured by SLM. - Highlights: • We studied the effect of pore size on bone tissue in-growth in a rabbit in vivo model. • Titanium samples with 300/600/900 μm pore size in three-dimensionally controlled shapes were fabricated by additive manufacturing. • Samples were

Surface Functionalization of Orthopedic Titanium Implants with Bone Sialoprotein.

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Andreas Baranowski

Full Text Available Orthopedic implant failure due to aseptic loosening and mechanical instability remains a major problem in total joint replacement. Improving osseointegration at the bone-implant interface may reduce micromotion and loosening. Bone sialoprotein (BSP has been shown to enhance bone formation when coated onto titanium femoral implants and in rat calvarial defect models. However, the most appropriate method of BSP coating, the necessary level of BSP coating, and the effect of BSP coating on cell behavior remain largely unknown. In this study, BSP was covalently coupled to titanium surfaces via an aminosilane linker (APTES, and its properties were compared to BSP applied to titanium via physisorption and untreated titanium. Cell functions were examined using primary human osteoblasts (hOBs and L929 mouse fibroblasts. Gene expression of specific bone turnover markers at the RNA level was detected at different intervals. Cell adhesion to titanium surfaces treated with BSP via physisorption was not significantly different from that of untreated titanium at any time point, whereas BSP application via covalent coupling caused reduced cell adhesion during the first few hours in culture. Cell migration was increased on titanium disks that were treated with higher concentrations of BSP solution, independent of the coating method. During the early phases of hOB proliferation, a suppressive effect of BSP was observed independent of its concentration, particularly when BSP was applied to the titanium surface via physisorption. Although alkaline phosphatase activity was reduced in the BSP-coated titanium groups after 4 days in culture, increased calcium deposition was observed after 21 days. In particular, the gene expression level of RUNX2 was upregulated by BSP. The increase in calcium deposition and the stimulation of cell differentiation induced by BSP highlight its potential as a surface modifier that could enhance the osseointegration of orthopedic implants

Pedicle screw loosening is correlated to chronic subclinical deep implant infection: a retrospective database analysis.

Science.gov (United States)

Leitner, Lukas; Malaj, Isabella; Sadoghi, Patrick; Amerstorfer, Florian; Glehr, Mathias; Vander, Klaus; Leithner, Andreas; Radl, Roman

2018-04-13

Spinal fusion is used for treatment of spinal deformities, degeneration, infection, malignancy, and trauma. Reduction of motion enables osseous fusion and permanent stabilization of segments, compromised by loosening of the pedicle screws (PS). Deep implant infection, biomechanical, and chemical mechanisms are suspected reasons for loosening of PS. Study objective was to investigate the frequency and impact of deep implant infection on PS loosening. Intraoperative infection screening from wound and explanted material sonication was performed during revision surgeries following dorsal stabilization. Case history events and factors, which might promote implant infections, were included in this retrospective survey. 110 cases of spinal metal explantation were included. In 29.1% of revision cases, infection screening identified a germ, most commonly Staphylococcus (53.1%) and Propionibacterium (40.6%) genus. Patients screened positive had a significant higher number of previous spinal operations and radiologic loosening of screws. Patients revised for adjacent segment failure had a significantly lower rate of positive infection screening than patients revised for directly implant associated reasons. Removal of implants that revealed positive screening effected significant pain relief. Chronic implant infection seems to play a role in PS loosening and ongoing pain, causing revision surgery after spinal fusion. Screw loosening and multiple prior spinal operations should be suspicious for implant infection after spinal fusion when it comes to revision surgery. These slides can be retrieved under Electronic Supplementary Material.

Osseointegration of titanium, titanium alloy and zirconia dental implants: current knowledge and open questions.

Science.gov (United States)

Bosshardt, Dieter D; Chappuis, Vivianne; Buser, Daniel

2017-02-01

Bone healing around dental implants follows the pattern and sequence of intramembraneous osteogenesis with formation of woven bone first of all followed later by formation of parallel-fibered and lamellar bone. Bone apposition onto the implant surface starts earlier in trabecular bone than in compact bone. While the first new bone may be found on the implant surface around 1 week after installation, bone remodeling starts at between 6 and 12 weeks and continues throughout life. Bone remodeling also involves the bone-implant interface, thus transiently exposing portions of the implant surface. Surface modifications creating micro-rough implant surfaces accelerate the osseointegration process of titanium implants, as demonstrated in numerous animal experiments. Sandblasting followed by acid-etching may currently be regarded as the gold standard technique to create micro-rough surfaces. Chemical surface modifications, resulting in higher hydrophilicity, further increase the speed of osseointegration of titanium and titanium-zirconium implants in both animals and humans. Surface modifications of zirconia and alumina-toughened zirconia implants also have an influence on the speed of osseointegration, and some implant types reach high bone-to-implant contact values in animals. Although often discussed independently of each other, surface characteristics, such as topography and chemistry, are virtually inseparable. Contemporary, well-documented implant systems with micro-rough implant surfaces, placed by properly trained and experienced clinicians, demonstrate high long-term survival rates. Nevertheless, implant failures do occur. A low percentage of implants are diagnosed with peri-implantitis after 10 years in function. In addition, a low number of implants seem to be lost for primarily reasons other than biofilm-induced infection. Patient factors, such as medications interfering with the immune system and bone cells, may be an element contributing to continuous bone

Titanium implants in irradiated dog mandibles

International Nuclear Information System (INIS)

Schweiger, J.W.

1989-01-01

The use of osseointegrated titanium implants has been a great benefit to selected cancer patients who otherwise would not be able to wear conventional and/or maxillofacial prostheses. Cognizant of the risk of osteoradionecrosis, we used an animal model to seek experimental evidence for successful osseointegration in bone irradiated to tumoricidal levels. Five healthy male beagle dogs received 60 gray to a previously edentulated and healed area of the right hemimandible. The left hemimandible was kept as a nonirradiated control. After 9 months, titanium implants were placed and allowed an additional 5 1/2 months to osseointegrate. At that time, block specimens were obtained, radiographed, photographed, and analyzed histologically. Although statistical significance cannot be attached to the results, osseointegration was achieved in half of the irradiated specimens

Surface characterization of titanium based dental implants; Caracterizacao de implantes odontologicos a base de titanio

Energy Technology Data Exchange (ETDEWEB)

Castilho, Guilherme Augusto Alcaraz

2006-07-01

Dental implantology uses metallic devices made of commercially pure titanium in order to replace lost teeth. Titanium presents favorable characteristics as bio material and modern implants are capable of integrate, witch is the union between bone and implant without fibrous tissue development. Three of the major Brazilian implant manufacturers were chosen to join the study. A foreign manufacturer participated as standard. The manufacturers had three specimens of each implant with two different surface finishing, as machined and porous, submitted to analysis. Surface chemical composition and implant morphology were analyzed by X-ray photoelectron spectroscopy (XP S), scanning electron microscopy (SEM) and microprobe. Implant surface is mainly composed of titanium, oxygen and carbon. Few contaminants commonly present on implant surface were found on samples. Superficial oxide layer is basically composed of titanium dioxide (TiO{sub 2}), another oxides as Ti O and Ti{sub 2}O{sub 3} were also found in small amount. Carbon on implant surface was attributed to manufacturing process. Nitrogen, Phosphorous and Silicon appeared in smaller concentration on surface. There was no surface discrepancy among foreign and Brazilian made implants. SEM images were made on different magnification, 35 X to 3500 X, and showed similarity among as machined implants. Porous surface finishing implants presented distinct morphology. This result was attributed to differences on manufacturing process. Implant bioactivity was accessed through immersion on simulated body solution (SBF) in order to verify formation of an hydroxyapatite (HA) layer on surface. Samples were divided on three groups according to immersion time: G1 (7 days), G2 (14 days), G3 (21 days), and deep in SBF solution at 37 deg C. After being removed from solution, XPS analyses were made and then implants have been submitted to microprobe analysis. XPS showed some components of SBF solution on sample surface but microprobe

Custom-made titanium devices as membranes for bone augmentation in implant treatment: Clinical application and the comparison with conventional titanium mesh.

Science.gov (United States)

Sumida, Tomoki; Otawa, Naruto; Kamata, Y U; Kamakura, Satoshi; Mtsushita, Tomiharu; Kitagaki, Hisashi; Mori, Shigeo; Sasaki, Kiyoyuki; Fujibayashi, Shunsuke; Takemoto, Mitsuru; Yamaguchi, Atsushi; Sohmura, Taiji; Nakamura, Takashi; Mori, Yoshihide

2015-12-01

Development of new custom-made devices to reconstruct alveolar bone for implantation, and comparison with conventional methods were the goals of this study. Using a computer-aided design technique, three-dimensional images were constructed. From these data, custom-made devices were produced by a selective laser melting method with pure titanium. Clinical trials also have been conducted with 26 participants who needed bone reconstruction before implantation; they were divided into 2 groups with 13 patients each. The first group uses custom-made devices; the other uses commercial titanium meshes that need to bend during operation. Some clinical aspects are evaluated after the trial. The custom-made devices can be produced closely by following the data precisely. Devices are fit for bone defect site. Moreover, the operation time of the custom-made group (75.4 ± 11.6 min) was significantly shorter than that of the conventional group (111.9 ± 17.8 min) (p < 0.01). Mucosal rupture occurs, without significant difference (p = 0.27), in a patient in the custom-made without severe infection (7.7%), and 3 in conventional (23.1%), respectively. The retaining screw is significantly fewer in the custom-made group than commercial mesh group (p < 0.01). These results indicate that our novel protocol could be simple and safe for providing powerful support for guided bone regeneration. Copyright © 2015 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

Repositioning Titanium: An In Vitro Evaluation of Laser-Generated Microporous, Microrough Titanium Templates As a Potential Bridging Interface for Enhanced Osseointegration and Durability of Implants

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Daniel Tang

2017-12-01

Full Text Available Although titanium alloys remain the preferred biomaterials for the manufacture of biomedical implants today, such devices can fail within 15 years of implantation due to inadequate osseointegration. Furthermore, wear debris toxicity due to alloy metal ion release has been found to cause side-effects including neurotoxicity and chronic inflammation. Titanium, with its known biocompatibility, corrosion resistance, and high elastic modulus, could if harnessed in the form of a superficial scaffold or bridging device, resolve such issues. A novel three-dimensional culture approach was used to investigate the potential osteoinductive and osseointegrative capabilities of a laser-generated microporous, microrough medical grade IV titanium template on human skeletal stem cells (SSCs. Human SSCs seeded on a rough 90-µm pore surface of ethylene oxide-sterilized templates were observed to be strongly adherent, and to display early osteogenic differentiation, despite their inverted culture in basal conditions over 21 days. Limited cellular migration across the template surface highlighted the importance of high surface wettability in maximizing cell adhesion, spreading and cell-biomaterial interaction, while restricted cell ingrowth within the conical-shaped pores underlined the crucial role of pore geometry and size in determining the extent of osseointegration of an implant device. The overall findings indicate that titanium only devices, with appropriate optimizations to porosity and surface wettability, could yet play a major role in improving the long-term efficacy, durability, and safety of future implant technology.

SLM Produced Porous Titanium Implant Improvements for Enhanced Vascularization and Osteoblast Seeding

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Julia Matena

2015-04-01

Full Text Available To improve well-known titanium implants, pores can be used for increasing bone formation and close bone-implant interface. Selective Laser Melting (SLM enables the production of any geometry and was used for implant production with 250-µm pore size. The used pore size supports vessel ingrowth, as bone formation is strongly dependent on fast vascularization. Additionally, proangiogenic factors promote implant vascularization. To functionalize the titanium with proangiogenic factors, polycaprolactone (PCL coating can be used. The following proangiogenic factors were examined: vascular endothelial growth factor (VEGF, high mobility group box 1 (HMGB1 and chemokine (C-X-C motif ligand 12 (CXCL12. As different surfaces lead to different cell reactions, titanium and PCL coating were compared. The growing into the porous titanium structure of primary osteoblasts was examined by cross sections. Primary osteoblasts seeded on the different surfaces were compared using Live Cell Imaging (LCI. Cross sections showed cells had proliferated, but not migrated after seven days. Although the cell count was lower on titanium PCL implants in LCI, the cell count and cell spreading area development showed promising results for titanium PCL implants. HMGB1 showed the highest migration capacity for stimulating the endothelial cell line. Future perspective would be the incorporation of HMGB1 into PCL polymer for the realization of a slow factor release.

SLM Produced Porous Titanium Implant Improvements for Enhanced Vascularization and Osteoblast Seeding

Science.gov (United States)

Matena, Julia; Petersen, Svea; Gieseke, Matthias; Kampmann, Andreas; Teske, Michael; Beyerbach, Martin; Murua Escobar, Hugo; Haferkamp, Heinz; Gellrich, Nils-Claudius; Nolte, Ingo

2015-01-01

To improve well-known titanium implants, pores can be used for increasing bone formation and close bone-implant interface. Selective Laser Melting (SLM) enables the production of any geometry and was used for implant production with 250-µm pore size. The used pore size supports vessel ingrowth, as bone formation is strongly dependent on fast vascularization. Additionally, proangiogenic factors promote implant vascularization. To functionalize the titanium with proangiogenic factors, polycaprolactone (PCL) coating can be used. The following proangiogenic factors were examined: vascular endothelial growth factor (VEGF), high mobility group box 1 (HMGB1) and chemokine (C-X-C motif) ligand 12 (CXCL12). As different surfaces lead to different cell reactions, titanium and PCL coating were compared. The growing into the porous titanium structure of primary osteoblasts was examined by cross sections. Primary osteoblasts seeded on the different surfaces were compared using Live Cell Imaging (LCI). Cross sections showed cells had proliferated, but not migrated after seven days. Although the cell count was lower on titanium PCL implants in LCI, the cell count and cell spreading area development showed promising results for titanium PCL implants. HMGB1 showed the highest migration capacity for stimulating the endothelial cell line. Future perspective would be the incorporation of HMGB1 into PCL polymer for the realization of a slow factor release. PMID:25849656

Determining the Young's modulus of a cellular titanium implant by FEM simulation

Science.gov (United States)

Loginov, Yu. N.; Golodnov, A. I.; Stepanov, S. I.; Kovalev, E. Yu.

2017-12-01

The role of additive manufacturing is noted for the construction of titanium medical implants. The purpose of the study is to determine the Young's modulus of cellular titanium implants, which is based on calculations performed by finite element analysis. A honeycomb structure from intersecting cylinder surfaces is offered for the implant made of the Ti-6Al-4V alloy. Boundary conditions are stated for the loading of the implant structure. It is demonstrated that the Young's modulus can be reduced more than three times comparing to a solid titanium alloy. Zones of strain and stress localization located near the abutment of the cylindrical surfaces. Recommendations for the further improvement of the implant architecture are generated.

Titanium implants with modified surfaces: Meta-analysis of in vivo osteointegration

Energy Technology Data Exchange (ETDEWEB)

Gasik, Michael, E-mail: michael.gasik@aalto.fi [Aalto University Foundation, School of Chemical Technology, P.O. Box 16200, FIN-00076 AALTO (Finland); Braem, Annabel [Department of Metallurgy and Materials Engineering, KU Leuven, Kasteelpark Arenberg 44, B-3001 Heverlee (Belgium); Chaudhari, Amol; Duyck, Joke [Department of Prosthetic Dentistry, BIOMAT Research Cluster, KU Leuven, Kapucijnenvoer 7a, B-3000 Leuven (Belgium); Vleugels, Jozef [Department of Metallurgy and Materials Engineering, KU Leuven, Kasteelpark Arenberg 44, B-3001 Heverlee (Belgium)

2015-04-01

Titanium-based implants are widely used in modern clinical practice, but their “optimal” properties in terms of porosity and topology, roughness and hydrophilic parameters are being a subject of intensive discussions. Recent in vitro results have shown a possibility to optimize the surface of an implant with maximal repelling of bacteria (Staphylococcus aureus, Staphylococcus epidermidis) and improvement in human osteogenic and endothelial cell adhesion, proliferation and differentiation. In this work, these different grades titanium implants were tested in vivo using the same analytical methodology. In addition to material parameters, key histomorphometrical parameters such a regeneration area, bone adaptation area and bone-to-implant contact were determined after 2 and 4 weeks of implantation in rabbit animal model. Porous implants have more clear differences than non-porous ones, with the best optimum values obtained on hydrothermally treated electrophoretically deposited titanium. These in vivo data correlate well with the optimal prediction made by in vitro tests. - Highlights: • Various titanium specimens were studied in vivo on osteointegration vs their properties. • Non-porous implants had a better performance when coated with bioactive glass. • Porous implants have shown the best results for hydrothermally treated specimens. • Good correlation was found with the previous in vitro tests. • New analysis of the in vivo data has shown benefits to assess biomaterials performance.

Titanium implants with modified surfaces: Meta-analysis of in vivo osteointegration

International Nuclear Information System (INIS)

Gasik, Michael; Braem, Annabel; Chaudhari, Amol; Duyck, Joke; Vleugels, Jozef

2015-01-01

Titanium-based implants are widely used in modern clinical practice, but their “optimal” properties in terms of porosity and topology, roughness and hydrophilic parameters are being a subject of intensive discussions. Recent in vitro results have shown a possibility to optimize the surface of an implant with maximal repelling of bacteria (Staphylococcus aureus, Staphylococcus epidermidis) and improvement in human osteogenic and endothelial cell adhesion, proliferation and differentiation. In this work, these different grades titanium implants were tested in vivo using the same analytical methodology. In addition to material parameters, key histomorphometrical parameters such a regeneration area, bone adaptation area and bone-to-implant contact were determined after 2 and 4 weeks of implantation in rabbit animal model. Porous implants have more clear differences than non-porous ones, with the best optimum values obtained on hydrothermally treated electrophoretically deposited titanium. These in vivo data correlate well with the optimal prediction made by in vitro tests. - Highlights: • Various titanium specimens were studied in vivo on osteointegration vs their properties. • Non-porous implants had a better performance when coated with bioactive glass. • Porous implants have shown the best results for hydrothermally treated specimens. • Good correlation was found with the previous in vitro tests. • New analysis of the in vivo data has shown benefits to assess biomaterials performance

The effects of implant surface roughness and surgical technique on implant fixation in an in vitro model.

NARCIS (Netherlands)

Shalabi, M.M.; Wolke, J.G.C.; Jansen, J.A.

2006-01-01

OBJECTIVES: The aim of the present study was to determine the relationship between implant surface parameters, surgical approach and initial implant fixation. MATERIAL AND METHODS: Sixty tapered, conical, screw-shaped implants with machined or etched surface topography were implanted into the

Surface analysis of titanium dental implants with different topographies

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Silva M.H. Prado da

2000-01-01

Full Text Available Cylindrical dental implants made of commercially pure titanium were analysed in four different surface finishes: as-machined, Al2O3 blasted with Al2O3 particles, plasma-sprayed with titanium beads and electrolytically coated with hydroxyapatite. Scanning electron microscopy (SEM with Energy Dispersive X-ray Analysis (EDX revealed the topography of the surfaces and provided qualitative results of the chemical composition of the different implants. X-ray Photoelectron Spectroscopy (XPS was used to perform chemical analysis on the surface of the implants while Laser Scanning Confocal Microscopy (LSM produced topographic maps of the analysed surfaces. Optical Profilometry was used to quantitatively characterise the level of roughness of the surfaces. The implant that was plasma-sprayed and the hydroxyapatite coated implant showed the roughest surface, followed by the implant blasted with alumina and the as-machined implant. Some remnant contamination from the processes of blasting, coating and cleaning was detected by XPS.

Stress analysis of implant-bone fixation at different fracture angle

Science.gov (United States)

Izzawati, B.; Daud, R.; Afendi, M.; Majid, MS Abdul; Zain, N. A. M.; Bajuri, Y.

2017-10-01

Internal fixation is a mechanism purposed to maintain and protect the reduction of a fracture. Understanding of the fixation stability is necessary to determine parameters influence the mechanical stability and the risk of implant failure. A static structural analysis on a bone fracture fixation was developed to simulate and analyse the biomechanics of a diaphysis shaft fracture with a compression plate and conventional screws. This study aims to determine a critical area of the implant to be fractured based on different implant material and angle of fracture (i.e. 0°, 30° and 45°). Several factors were shown to influence stability to implant after surgical. The stainless steel, (S. S) and Titanium, (Ti) screws experienced the highest stress at 30° fracture angle. The fracture angle had a most significant effect on the conventional screw as compared to the compression plate. The stress was significantly higher in S.S material as compared to Ti material, with concentrated on the 4th screw for all range of fracture angle. It was also noted that the screws closest to the intense concentration stress areas on the compression plate experienced increasing amounts of stress. The highest was observed at the screw thread-head junction.

Release of metal in vivo from stressed and nonstressed maxillofacial fracture plates and screws.

Science.gov (United States)

Matthew, I R; Frame, J W

2000-07-01

To analyze the release of metal into the adjacent tissues from stressed and nonstressed titanium and stainless steel miniplates and screws. Two miniplates were inserted into the cranial vaults of 12 beagle dogs while they were under general endotracheal anesthesia. One miniplate was shaped to fit the curvature of the skull (control). Another miniplate, made of the same material, was bent in a curve until the midpoint was raised 3 mm above the ends. Screws were inserted and tightened until the plate conformed to the skull curvature, creating stresses in the system. Four animals (2 each, having titanium or stainless steel plates and screws) were killed after 4, 12, and 24 weeks. Metallosis of adjacent soft tissues was assessed qualitatively. Miniplates and screws were removed, and adjacent soft tissue and bone was excised. Titanium, iron, chromium, nickel, and aluminum levels were assayed by ultraviolet/visible light and atomic absorption spectrophotometry. Nonparametric statistical methods were used for data analysis. There was no clear relationship between pigmentation of soft tissue adjacent to the miniplates and screws and the concentrations of metal present. The data did not demonstrate any consistent differences in the concentrations of metallic elements next to stressed and nonstressed (control) miniplates and screws of either material. Stresses arising through poor contouring of miniplates do not appear to influence the extent of release of metal into the adjacent tissues.

Gentamicin coating of nanotubular anodized titanium implant reduces implant-related osteomyelitis and enhances bone biocompatibility in rabbits

Directory of Open Access Journals (Sweden)

Liu D

2017-07-01

Full Text Available Denghui Liu,1,* Chongru He,2,* Zhongtang Liu,2 Weidong Xu2 1Department of Orthopedics, the 113 Military Hospital, Ningbo, 2Department of Orthopedics, Changhai Hospital Affiliated to the Second Military Medical University, Shanghai, People’s Republic of China *These authors contributed equally to this work Abstract: Titanium and titanium alloy are widely used as orthopedic implants for their favorable mechanical properties and satisfactory biocompatibility. The aim of the present study was to investigate the antibacterial effect and bone cell biocompatibility of a novel implant made with nanotubular anodized titanium coated with gentamicin (NTATi-G through in vivo study in ­rabbits. The animals were divided into four groups, each receiving different kinds of implants, that is, NTATi-G, titanium coated with gentamicin (Ti-G, nanotubular anodized titanium uncoated with gentamicin (NTATi and titanium uncoated with gentamicin (Ti. The results showed that NTATi-G implant prevented implant-related osteomyelitis and enhanced bone biocompatibility in vivo. Moreover, the body temperature of rabbits in NTATi-G and Ti-G groups was lower than those in Ti groups, while the weight of rabbits in NTATi-G and Ti-G groups was heavier than those in NTATi and Ti groups, respectively. White blood cell counts in NTATi-G group were lower than NTATi and Ti groups. Features of myelitis were observed by X-ray films in the NTATi and Ti groups, but not in the NTATi-G and Ti-G groups. The radiographic scores, which assessed pathology and histopathology in bone tissues, were significantly lower in the NTATi-G and Ti-G groups than those in the NTATi and Ti groups, respectively (P<0.05. Meanwhile, explants and bone tissue culture demonstrated significantly less bacterial growth in the NTATi-G and Ti-G groups than in the NTATi and Ti groups, respectively (P<0.01. The bone volume in NTATi-G group was greater than Ti-G group, and little bone formation was seen in NTATi and Ti

Revival of pure titanium for dynamically loaded porous implants using additive manufacturing.

Science.gov (United States)

Wauthle, Ruben; Ahmadi, Seyed Mohammad; Amin Yavari, Saber; Mulier, Michiel; Zadpoor, Amir Abbas; Weinans, Harrie; Van Humbeeck, Jan; Kruth, Jean-Pierre; Schrooten, Jan

2015-09-01

Additive manufacturing techniques are getting more and more established as reliable methods for producing porous metal implants thanks to the almost full geometrical and mechanical control of the designed porous biomaterial. Today, Ti6Al4V ELI is still the most widely used material for porous implants, and none or little interest goes to pure titanium for use in orthopedic or load-bearing implants. Given the special mechanical behavior of cellular structures and the material properties inherent to the additive manufacturing of metals, the aim of this study is to investigate the properties of selective laser melted pure unalloyed titanium porous structures. Therefore, the static and dynamic compressive properties of pure titanium structures are determined and compared to previously reported results for identical structures made from Ti6Al4V ELI and tantalum. The results show that porous Ti6Al4V ELI still remains the strongest material for statically loaded applications, whereas pure titanium has a mechanical behavior similar to tantalum and is the material of choice for cyclically loaded porous implants. These findings are considered to be important for future implant developments since it announces a potential revival of the use of pure titanium for additively manufactured porous implants. Copyright © 2015 Elsevier B.V. All rights reserved.

Ion implantation induced nanotopography on titanium and bone cell adhesion

Energy Technology Data Exchange (ETDEWEB)

Braceras, Iñigo, E-mail: inigo.braceras@tecnalia.com [Tecnalia, Mikeletegi Pasealekua 2, 20009 Donostia-San Sebastian (Spain); CIBER de Bioingeniería, Biomateriales y Nanomedicina (Ciber-BBN) (Spain); Vera, Carolina; Ayerdi-Izquierdo, Ana [Tecnalia, Mikeletegi Pasealekua 2, 20009 Donostia-San Sebastian (Spain); CIBER de Bioingeniería, Biomateriales y Nanomedicina (Ciber-BBN) (Spain); Muñoz, Roberto [Tecnalia, Mikeletegi Pasealekua 2, 20009 Donostia-San Sebastian (Spain); Lorenzo, Jaione; Alvarez, Noelia [Tecnalia, Mikeletegi Pasealekua 2, 20009 Donostia-San Sebastian (Spain); CIBER de Bioingeniería, Biomateriales y Nanomedicina (Ciber-BBN) (Spain); Maeztu, Miguel Ángel de [Private Practice, P° San Francisco, 43 A-1°, 20400 Tolosa (Spain)

2014-08-15

Graphical abstract: Titanium surfaces modified by inert ion implantation affect cell adhesion through modification of the nanotopography in the same dimensional range of that of human bone inorganic phases. - Highlights: • Inert ion implantation on Ti modifies surface nanotopography and bone cell adhesion. • Ion implantation can produce nanostructured surfaces on titanium in the very same range as of those of the mineral phase of the human bone. • Appropriate tool for studying the relevance of nanostructured surfaces on bone mineralization and implant osseointegration. • Ion implantation induced nanotopography have a statistically significant influence on bone cell adhesion. - Abstract: Permanent endo-osseous implants require a fast, reliable and consistent osseointegration, i.e. intimate bonding between bone and implant, so biomechanical loads can be safely transferred. Among the parameters that affect this process, it is widely admitted that implant surface topography, surface energy and composition play an important role. Most surface treatments to improve osseointegration focus on micro-scale features, as few can effectively control the effects of the treatment at nanoscale. On the other hand, ion implantation allows controlling such nanofeatures. This study has investigated the nanotopography of titanium, as induced by different ion implantation surface treatments, its similarity with human bone tissue structure and its effect on human bone cell adhesion, as a first step in the process of osseointegration. The effect of ion implantation treatment parameters such as energy (40–80 keV), fluence (1–2 e17 ion/cm{sup 2}) and ion species (Kr, Ar, Ne and Xe) on the nanotopography of medical grade titanium has been measured and assessed by AFM and contact angle. Then, in vitro tests have been performed to assess the effect of these nanotopographies on osteoblast adhesion. The results have shown that the nanostructure of bone and the studied ion implanted

Ion implantation induced nanotopography on titanium and bone cell adhesion

International Nuclear Information System (INIS)

Braceras, Iñigo; Vera, Carolina; Ayerdi-Izquierdo, Ana; Muñoz, Roberto; Lorenzo, Jaione; Alvarez, Noelia; Maeztu, Miguel Ángel de

2014-01-01

Graphical abstract: Titanium surfaces modified by inert ion implantation affect cell adhesion through modification of the nanotopography in the same dimensional range of that of human bone inorganic phases. - Highlights: • Inert ion implantation on Ti modifies surface nanotopography and bone cell adhesion. • Ion implantation can produce nanostructured surfaces on titanium in the very same range as of those of the mineral phase of the human bone. • Appropriate tool for studying the relevance of nanostructured surfaces on bone mineralization and implant osseointegration. • Ion implantation induced nanotopography have a statistically significant influence on bone cell adhesion. - Abstract: Permanent endo-osseous implants require a fast, reliable and consistent osseointegration, i.e. intimate bonding between bone and implant, so biomechanical loads can be safely transferred. Among the parameters that affect this process, it is widely admitted that implant surface topography, surface energy and composition play an important role. Most surface treatments to improve osseointegration focus on micro-scale features, as few can effectively control the effects of the treatment at nanoscale. On the other hand, ion implantation allows controlling such nanofeatures. This study has investigated the nanotopography of titanium, as induced by different ion implantation surface treatments, its similarity with human bone tissue structure and its effect on human bone cell adhesion, as a first step in the process of osseointegration. The effect of ion implantation treatment parameters such as energy (40–80 keV), fluence (1–2 e17 ion/cm 2 ) and ion species (Kr, Ar, Ne and Xe) on the nanotopography of medical grade titanium has been measured and assessed by AFM and contact angle. Then, in vitro tests have been performed to assess the effect of these nanotopographies on osteoblast adhesion. The results have shown that the nanostructure of bone and the studied ion implanted

Marginal Vertical Fit along the Implant-Abutment Interface: A Microscope Qualitative Analysis

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Nicola Mobilio

2016-09-01

Full Text Available The aim of this study was to qualitatively evaluate the marginal vertical fit along two different implant-abutment interfaces: (1 a standard abutment on an implant and (2 a computer-aided-design/computer-aided-machine (CAD/CAM customized screw-retained crown on an implant. Four groups were compared: three customized screw-retained crowns with three different “tolerance” values (CAD-CAM 0, CAD-CAM +1, CAD-CAM −1 and a standard titanium abutment. Qualitative analysis was carried out using an optical microscope. Results showed a vertical gap significantly different from both CAD-CAM 0 and CAD-CAM −1, while no difference was found between standard abutment and CAD-CAM +1. The set tolerance in producing CAD/CAM screw-retained crowns plays a key role in the final fit.

The effect of DLC-coating deposition method on the reliability and mechanical properties of abutment's screws.

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Bordin, Dimorvan; Coelho, Paulo G; Bergamo, Edmara T P; Bonfante, Estevam A; Witek, Lukasz; Del Bel Cury, Altair A

2018-04-10

To characterize the mechanical properties of different coating methods of DLC (diamond-like carbon) onto dental implant abutment screws, and their effect on the probability of survival (reliability). Seventy-five abutment screws were allocated into three groups according to the coating method: control (no coating); UMS - DLC applied through unbalanced magnetron sputtering; RFPA-DLC applied through radio frequency plasma-activated (n=25/group). Twelve screws (n=4) were used to determine the hardness and Young's modulus (YM). A 3D finite element model composed of titanium substrate, DLC-layer and a counterpart were constructed. The deformation (μm) and shear stress (MPa) were calculated. The remaining screws of each group were torqued into external hexagon abutments and subjected to step-stress accelerated life-testing (SSALT) (n=21/group). The probability Weibull curves and reliability (probability survival) were calculated considering the mission of 100, 150 and 200N at 50,000 and 100,000 cycles. DLC-coated experimental groups evidenced higher hardness than control (p1 indicating that fatigue contributed to failure. High reliability was depicted at a mission of 100N. At 200N a significant decrease in reliability was detected for all groups (ranging from 39% to 66%). No significant difference was observed among groups regardless of mission. Screw fracture was the chief failure mode. DLC-coating have been used to improve titanium's mechanical properties and increase the reliability of dental implant-supported restorations. Copyright © 2018 The Academy of Dental Materials. Published by Elsevier Inc. All rights reserved.

Carbon film coating of abutment surfaces: effect on the abutment screw removal torque.

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Corazza, Pedro Henrique; de Moura Silva, Alecsandro; Cavalcanti Queiroz, José Renato; Salazar Marocho, Susana María; Bottino, Marco Antonia; Massi, Marcos; de Assunção e Souza, Rodrigo Othávio

2014-08-01

To evaluate the effect of diamond-like carbon (DLC) coating of prefabricated implant abutment on screw removal torque (RT) before and after mechanical cycling (MC). Fifty-four abutments for external-hex implants were divided among 6 groups (n = 9): S, straight abutment (control); SC, straight coated abutment; SCy, straight abutment and MC; SCCy, straight coated abutment and MC; ACy, angled abutment and MC; and ACCy, angled coated abutment and MC. The abutments were attached to the implants by a titanium screw. RT values were measured and registered. Data (in Newton centimeter) were analyzed with analysis of variance and Dunnet test (α = 0.05). RT values were significantly affected by MC (P = 0.001) and the interaction between DLC coating and MC (P = 0.038). SCy and ACy showed the lowest RT values, statistically different from the control. The abutment coated groups had no statistical difference compared with the control. Scanning electron microscopy analysis showed DLC film with a thickness of 3 μm uniformly coating the hexagonal abutment. DLC film deposited on the abutment can be used as an alternative procedure to reduce abutment screw loosening.

Effect of polymer coating on the osseointegration of CP-Ti dental implant

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Al-Hassani, Emad; Al-Hassani, Fatima; Najim, Manar

2018-05-01

Modifications achieved coatings of titanium samples were investigated in order to improve their surface characteristics so as to facilitate bio-integration. Chitosan coating was use for commercial pure Ti alloys manufactured by two different methods in which commercial pure titanium rod converted in form of implant screw by using wire cut machine and lathe, second method included the used of powder technology for producing the implant screws. The coating process of chitosan polymer was carried out using advance technology (electrospnning process) to create fibrous structure from Nano to micro scale of the chitosan on the implant surface which result in a bioactive surface. The characterization includes; microstructure observation, surface chemical composition analysis (EDS), surface roughness (AFM), and the histological analysis. from the SEM No morphological differences were observed among the implants surfaces except for some inconsiderable morphological differences that results from the manufacturing process, by using EDX analysis the surfaces chemical compositions were completely changed and there was large decrease in the percentage of titanium element at the surface which indicates that the surface is covered with chitosan and had a new surface composition and topography. The sample was produced by powder technology process have higher roughness (845.36 nm) than sample produced by machining without any surface treatment (531.7nm),finally The histological view of implant samples after 4weeks of implantation, showed active bone formation in all implant surface which give clear indication of tissue acceptance.

Implant Material, Type of Fixation at the Shaft, and Position of Plate Modify Biomechanics of Distal Femur Plate Osteosynthesis.

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Kandemir, Utku; Augat, Peter; Konowalczyk, Stefanie; Wipf, Felix; von Oldenburg, Geert; Schmidt, Ulf

2017-08-01

To investigate whether (1) the type of fixation at the shaft (hybrid vs. locking), (2) the position of the plate (offset vs. contact) and (3) the implant material has a significant effect on (a) construct stiffness and (b) fatigue life in a distal femur extraarticular comminuted fracture model using the same design of distal femur periarticular locking plate. An extraarticular severely comminuted distal femoral fracture pattern (OTA/AO 33-A3) was simulated using artificial bone substitutes. Ten-hole distal lateral femur locking plates were used for fixation per the recommended surgical technique. At the distal metaphyseal fragment, all possible locking screws were placed. For the proximal diaphyseal fragment, different types of screws were used to create 4 different fixation constructs: (1) stainless steel hybrid (SSH), (2) stainless steel locked (SSL), (3) titanium locked (TiL), and (4) stainless steel locked with 5-mm offset at the diaphysis (SSLO). Six specimens of each construct configuration were tested. First, each specimen was nondestructively loaded axially to determine the stiffness. Then, each specimen was cyclically loaded with increasing load levels until failure. Construct Stiffness: The fixation construct with a stainless steel plate and hybrid fixation (SSH) had the highest stiffness followed by the construct with a stainless steel plate and locking screws (SSL) and were not statistically different from each other. Offset placement (SSLO) and using a titanium implant (TiL) significantly reduced construct stiffness. Fatigue Failure: The stainless steel with hybrid fixation group (SSH) withstood the most number of cycles to failure and higher loads, followed by the stainless steel plate and locking screw group (SSL), stainless steel plate with locking screws and offset group (SSLO), and the titanium plate and locking screws group (TiL) consecutively. Offset placement (SSLO) as well as using a titanium implant (TiL) reduced cycles to failure. Using the

Effect of screw access hole preparation on fracture load of implant-supported zirconia-based crowns: an in vitro study

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Hadi Mokhtarpour

2016-07-01

Full Text Available Background. Fracture load of implant-supported restorations is an important factor in clinical success. This study evaluated the effect of two techniques for screw access hole preparation on the fracture load of cement-screw-retained implant-supported zirconia-based crowns. Methods. Thirty similar cement-screw-retained implant-supported zirconia-based maxillary central incisor crowns were evaluated in three groups of 10. Group NH: with no screw access holes for the control; Group HBS: with screw access holes prepared with a machine before zirconia sintering; Group HAS: with screw access holes prepared manually after zirconia sintering. In group HBS, the access holes were virtually designed and prepared by a computer-assisted design/computer-assisted manufacturing system. In group HAS, the access holes were manually prepared after zirconia sintering using a diamond bur. The dimensions of the screw access holes were equal in both groups. The crowns were cemented onto same-size abutments and were then subjected to thermocycling. The fracture load values of the crowns were measured using a universal testing machine. Data were analyzed with ANOVA and Tukey test (P < 0.05. Results. The mean fracture load value for the group NH was 888.37 ± 228.92 N, which was the highest among the groups, with a significant difference (P < 0.0001. The fracture load values were 610.48 ± 125.02 N and 496.74 ± 104.10 Nin the HBS and HAS groups, respectively, with no significant differences (P = 0.44. Conclusion. Both techniques used for preparation of screw access holes in implant-supported zirconia-based crowns de-creased the fracture load.

Bone response to a titanium aluminium nitride coating on metallic implants.

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Freeman, C O; Brook, I M

2006-05-01

The design, surface characteristics and strength of metallic implants are dependant on their intended use and clinical application. Surface modifications of materials may enable reduction of the time taken for osseointegration and improve the biological response of bio-mechanically favourable metals and alloys. The influence of a titanium aluminium nitride (TAN) coating on the response of bone to commercially pure titanium and austenitic 18/8 stainless steel wire is reported. TAN coated and plain rods of stainless steel and commercially pure titanium were implanted into the mid-shaft of the femur of Wistar rats. The femurs were harvested at four weeks and processed for scanning electron and light microscopy. All implants exhibited a favourable response in bone with no evidence of fibrous encapsulation. There was no significant difference in the amount of new bone formed around the different rods (osseoconduction), however, there was a greater degree of shrinkage separation of bone from the coated rods than from the plain rods (p = 0.017 stainless steel and p = 0.0085 titanium). TAN coating may result in reduced osseointegration between bone and implant.

Adhesion of osteoblasts to a nanorough titanium implant surface

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Gongadze E

2011-08-01

Full Text Available Ekaterina Gongadze1, Doron Kabaso2, Sebastian Bauer3, Tomaž Slivnik2, Patrik Schmuki3, Ursula van Rienen1, Aleš Iglič21Institute of General Electrical Engineering, University of Rostock, Rostock, Germany; 2Laboratory of Biophysics, Faculty of Electrical Engineering, University of Ljubljana, Ljubljana, Slovenia; 3Department of Materials Science, Friedrich-Alexander University of Erlangen-Nurenberg, Erlangen, GermanyAbstract: This work considers the adhesion of cells to a nanorough titanium implant surface with sharp edges. The basic assumption was that the attraction between the negatively charged titanium surface and a negatively charged osteoblast is mediated by charged proteins with a distinctive quadrupolar internal charge distribution. Similarly, cation-mediated attraction between fibronectin molecules and the titanium surface is expected to be more efficient for a high surface charge density, resulting in facilitated integrin mediated osteoblast adhesion. We suggest that osteoblasts are most strongly bound along the sharp convex edges or spikes of nanorough titanium surfaces where the magnitude of the negative surface charge density is the highest. It is therefore plausible that nanorough regions of titanium surfaces with sharp edges and spikes promote the adhesion of osteoblasts.Keywords: osteoblasts, nanostructures, adhesion, titanium implants, osteointegration

Axial displacement of abutments into implants and implant replicas, with the tapered cone-screw internal connection, as a function of tightening torque.

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Dailey, Bruno; Jordan, Laurence; Blind, Olivier; Tavernier, Bruno

2009-01-01

The passive fit of a superstructure on implant abutments is essential to success. One source of error when using a tapered cone-screw internal connection may be the difference between the tightening torque level applied to the abutments by the laboratory technician compared to that applied by the treating clinician. The purpose of this study was to measure the axial displacement of tapered cone-screw abutments into implants and their replicas as a function of the tightening torque level. Twenty tapered cone-screw abutments were selected. Two groups were created: 10 abutments were secured into 10 implants, and 10 abutments were secured into 10 corresponding implant replicas. Each abutment was tightened in increasing increments of 5 Ncm, from 0 Ncm to 45 Ncm, with a torque controller. The length of each sample was measured repeatedly with an Electronic Digital Micrometer. The mean axial displacement for the implant group and the replica group was calculated. The data were analyzed by the Mann-Whitney and Spearman tests. For both groups, there was always an axial displacement of the abutment upon each incremental application of torque. The mean axial displacement values varied between 7 and 12 microm for the implant group and between 6 and 21 microm for the replica group at each 5-Ncm increment. From 0 to 45 Ncm, the total mean axial displacement values were 89 microm for the implant group and 122 microm for the replica group. There was a continuous axial displacement of the abutments into implants and implant replicas when the applied torque was raised from 0 to 45 Ncm. Torque applied above the level recommended by the manufacturer increased the difference in displacement between the two groups.

Titanium Implant Osseointegration Problems with Alternate Solutions Using Epoxy/Carbon-Fiber-Reinforced Composite

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Richard C. Petersen

2014-12-01

Full Text Available The aim of the article is to present recent developments in material research with bisphenyl-polymer/carbon-fiber-reinforced composite that have produced highly influential results toward improving upon current titanium bone implant clinical osseointegration success. Titanium is now the standard intra-oral tooth root/bone implant material with biocompatible interface relationships that confer potential osseointegration. Titanium produces a TiO2 oxide surface layer reactively that can provide chemical bonding through various electron interactions as a possible explanation for biocompatibility. Nevertheless, titanium alloy implants produce corrosion particles and fail by mechanisms generally related to surface interaction on bone to promote an inflammation with fibrous aseptic loosening or infection that can require implant removal. Further, lowered oxygen concentrations from poor vasculature at a foreign metal surface interface promote a build-up of host-cell-related electrons as free radicals and proton acid that can encourage infection and inflammation to greatly influence implant failure. To provide improved osseointegration many different coating processes and alternate polymer matrix composite (PMC solutions have been considered that supply new designing potential to possibly overcome problems with titanium bone implants. Now for important consideration, PMCs have decisive biofunctional fabrication possibilities while maintaining mechanical properties from addition of high-strengthening varied fiber-reinforcement and complex fillers/additives to include hydroxyapatite or antimicrobial incorporation through thermoset polymers that cure at low temperatures. Topics/issues reviewed in this manuscript include titanium corrosion, implant infection, coatings and the new epoxy/carbon-fiber implant results discussing osseointegration with biocompatibility related to nonpolar molecular attractions with secondary bonding, carbon fiber in vivo

Cell-laden hydrogel/titanium microhybrids: Site-specific cell delivery to metallic implants for improved integration.

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Koenig, Geraldine; Ozcelik, Hayriye; Haesler, Lisa; Cihova, Martina; Ciftci, Sait; Dupret-Bories, Agnes; Debry, Christian; Stelzle, Martin; Lavalle, Philippe; Vrana, Nihal Engin

2016-03-01

Porous titanium implants are widely used in dental, orthopaedic and otorhinolaryngology fields to improve implant integration to host tissue. A possible step further to improve the integration with the host is the incorporation of autologous cells in porous titanium structures via cell-laden hydrogels. Fast gelling hydrogels have advantageous properties for in situ applications such as localisation of specific cells and growth factors at a target area without dispersion. The ability to control the cell types in different regions of an implant is important in applications where the target tissue (i) has structural heterogeneity (multiple cell types with a defined spatial configuration with respect to each other); (ii) has physical property gradients essential for its function (such as in the case of osteochondral tissue transition). Due to their near immediate gelation, such gels can also be used for site-specific modification of porous titanium structures, particularly for implants which would face different tissues at different locations. Herein, we describe a step by step design of a model system: the model cell-laden gel-containing porous titanium implants in the form of titanium microbead/hydrogel (maleimide-dextran or maleimide-PVA based) microhybrids. These systems enable the determination of the effect of titanium presence on gel properties and encapsulated cell behaviour as a miniaturized version of full-scale implants, providing a system compatible with conventional analysis methods. We used a fibroblast/vascular endothelial cell co-cultures as our model system and by utilising single microbeads we have quantified the effect of gel microenvironment (degradability, presence of RGD peptides within gel formulation) on cell behaviour and the effect of the titanium presence on cell behaviour and gel formation. Titanium presence slightly changed gel properties without hindering gel formation or affecting cell viability. Cells showed a preference to move towards

In vitro effect of chlorhexidine gel on torque and detorque values of implant abutment screw

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Hamid Neshandar Asli

2017-01-01

Full Text Available Purpose: Use of chlorhexidine (CHX gel to eliminate the malodor of implant cavity may decrease the friction coefficient and effective preload and result in abutment screw loosening. This study aimed to assess the effect of CHX gel on the preload, torque, and detorque values. Materials and Methods: This in vitro experimental study was conducted on three groups of five implants. Group A (G1 was the control group and no material was applied to the implant cavity. In Group B (G2, implant cavity was filled with saliva before abutment screw tightening. In Group C (G3, implant cavity was first filled with saliva and then with CHX gel. The abutments were torqued to 24 N/cm2 according to the manufacturer's instructions and were then loosened. These processes were repeated five times. The ratio of the mean percentage of detorque to torque values was measured in all groups. The collected data were analyzed using ANOVA and post hoc Tukey's test. Results: No significant difference was noted between G1 and G2. Group G2 had significantly higher detorque value (p < 0.05. ANOVA detected a significant difference in the mean torque (p < 0.05 and detorque (p < 0.001 values among the three groups. G3 showed maximum difference between torque and detorque values; the minimum difference was noted in G2. Conclusion: Application of CHX gel (to decrease the malodor of the implant cavity decreases the detorque and preload values and increases the risk of screw loosening.

Treatment of unicameral calcaneal bone cysts in children: review of literature and results using a cannulated screw for continuous decompression of the cyst.

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Saraph, Vinay; Zwick, Ernst-Bernhard; Maizen, Claudia; Schneider, Frank; Linhart, Wolfgang E

2004-01-01

Nine unicameral bone cysts of the calcaneus in children were managed surgically using the technique of continuous decompression with titanium cannulated cancellous screws. The average age of the patients at surgery was 12.8 years. At follow-up a minimum of 2 years after surgery, eight cysts showed complete healing; one patient showed healing with residuals. Irritation at the screw insertion site necessitated early removal of the screw in one patient; implant-related problems were not observed in the other patients. Patients were allowed to bear weight after surgery. Implant extraction was performed after full consolidation of the cyst and was uneventful in all patients. A review of the literature and the different treatment modalities used for managing calcaneal cysts is also presented.

Efficacy of Octacalcium Phosphate Collagen Composite for Titanium Dental Implants in Dogs

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Tadashi Kawai

2018-02-01

Full Text Available Background: Previous studies showed that octacalcium (OCP collagen composite (OCP/Col can be used to repair human jaw bone defects without any associated abnormalities. The present study investigated whether OCP/Col could be applied to dental implant treatment using a dog tooth extraction socket model. Methods: The premolars of dogs were extracted; each extraction socket was extended, and titanium dental implants were placed in each socket. OCP/Col was inserted in the space around a titanium dental implant. Autologous bone was used to fill the other sockets, while the untreated socket (i.e., no bone substitute material served as a control. Three months after the operation, these specimens were analyzed for the osseointegration of each bone substitute material with the surface of the titanium dental implant. Results: In histomorphometric analyses, the peri-implant bone areas (BA% and bone-implant contact (BIC% were measured. There was no difference in BA% or BIC% between OCP/Col and autologous bone. Conclusion: These results suggested that OCP/Col could be used for implant treatment as a bone substitute.

Titanium versus zirconia implants supporting maxillary overdentures: three-dimensional finite element analysis.

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Osman, Reham B; Elkhadem, Amr H; Ma, Sunyoung; Swain, Michael V

2013-01-01

The purpose of this study was to compare the stress and strain occurring in peri-implant bone and implants used to support maxillary overdentures. Three-dimensional finite element analysis (3D FEA) was used to compare one-piece zirconia and titanium implants. Two types of implants were simulated using a 3D FEA model: one-piece zirconia and titanium implants (diameter, 3.8 × 11.5 mm) with 2.25-mm diameter ball abutments. In each simulation four implants were placed bilaterally in the canine/premolar region of an edentulous maxillary model. Static loads were applied axially and 20 degrees buccolingually on the buccal slope of the lingual cusps of posterior teeth of the first quadrant. Von Mises stresses and equivalent strains generated in peri-implant bone and first principal stresses in the implants were calculated. Comparable stress and strain values were shown in the peri-implant bone for both types of implants. The maximum equivalent strain produced in the peri-implant region was mostly within the range for bone augmentation. Under oblique loading, maximum von Mises stresses and equivalent strain were more evident at the neck of the most distal implant on the loaded side. Under axial load, the stress and strain were transferred to the peri-implant bone around the apex of the implant. Maximum tensile stresses that developed for either material were well below their fracture strength. The highest stresses were mainly located at the distobuccal region of the neck for the two implant materials under both loading conditions. From a biomechanical point of view, ceramic implants made from yttrium-stabilized tetragonal polycrystalline zirconia may be a potential alternative to conventional titanium implants for the support of overdentures. This is particularly relevant for a select group of patients with a proven allergy to titanium. Prospective clinical studies are still required to confirm these in vitro results. Different simulations presenting various cortical bone

In Vitro Evaluation of Manual Torque Values Applied to Implant-Abutment Complex by Different Clinicians and Abutment Screw Loosening

Science.gov (United States)

Demircan, Sabit; Cene, Erhan; Aya, Serhan Aydın; Erdem, Mehmet Ali; Cankaya, Abdulkadir Burak

2017-01-01

Preload is applied to screws manually or using a torque wrench in dental implant systems, and the preload applied must be appropriate for the purpose. The aim of this study was to assess screw loosening and bending/torsional moments applied by clinicians of various specialties following application of manual tightening torque to combinations of implants and abutments. Ten-millimeter implants of 3.7 and 4.1 mm diameters and standard or solid abutments were used. Each group contained five implant-abutment combinations. The control and experimental groups comprised 20 and 160 specimens, respectively. Implants in the experimental group were tightened by dentists of different specialties. Torsional and bending moments during tightening were measured using a strain gauge. Control group and implants with preload values close to the ideal preload were subjected to a dynamic loading test at 150 N, 15 Hz, and 85,000 cycles. The implants that deformed in this test were examined using an optical microscope to assess deformities. Manual tightening did not yield the manufacturer-recommended preload values. Dynamic loading testing suggested early screw loosening/fracture in samples with insufficient preload. PMID:28473988

The role of prosthetic abutment material on the stress distribution in a maxillary single implant-supported fixed prosthesis

International Nuclear Information System (INIS)

Peixoto, Hugo Eduardo; Bordin, Dimorvan; Del Bel Cury, Altair A.; Silva, Wander José da; Faot, Fernanda

2016-01-01

Purpose: Evaluate the influence of abutment's material and geometry on stress distribution in a single implant-supported prosthesis. Materials and Methods: Three-dimensional models were made based on tomographic slices of the upper middle incisor area, in which a morse taper implant was positioned and a titanium (Ti) or zirconia (ZrN) universal abutments was installed. The commercially available geometry of titanium (T) and zirconia (Z) abutments were used to draw two models, TM1 and ZM1 respectively, which served as control groups. These models were compared with 2 experimental groups were the mechanical properties of Z were applied to the titanium abutment (TM2) and vice versa for the zirconia abutment (ZM2). Subsequently, loading was simulated in two steps, starting with a preload phase, calculated with the respective friction coefficients of each materials, followed by a combined preload and chewing force. The maximum von Mises stress was described. Data were analyzed by two-way ANOVA that considered material composition, geometry and loading (p 0.05). Conclusion: The screw was the piece most intensely affected, mainly through the preload force, independent of the abutment's material. - Highlights: • The abutment's screw was the most impaired piece of the dental implant system. • The highest stress was located at first thread of the abutment's screw. • The preload is the main factor in the abutment's screw stress. • Abutment configuration and material can have a positive contribution for the stress distribution

SHEARING STRENGTH TEST OF ORTOPEDIC TITANIUM ALLOY SCREW PRODUCED IN THE PROCESS OF 3D TECHNOLOGY PRINTING

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Patrycja Ruszniak

2016-03-01

Full Text Available The aim of the present dissertation is the assessment of technical shear resistance (technological shear of orthopedic screw made of titanium alloy Ti6Al4V, produced using incremental technology in the process of 3D printing process. The first part of the work presents incremental techniques in production engineering. The second part of the present work contains specification of the 3D printing process of samples as well as the description of the used material. The fundamental part of the article is composed out of endurance tests for orthopaedic screws as well as the analysis of the obtained results and conclusions. The method of incremental production SLM using SLM 280HL metal printer was used during the technological process. The resistance tests were performed using ZWICK/ROELL Z150 machines. Identical endurance trials were performed for monolithic bars made of titanium alloys (of bar core size made on a wire electric discharge machine Sodick SL600Q for comparative purposes. The obtained test results enabled comparative assessment of the value of shear resistance Rt in the conditions of technological shear. According to the performed tests, the shear resistance Rt of orthopaedic screws is nearly 33% lower than of monolithic bars of the same core size.

Porous Structure Characterization in Titanium Coating for Surgical Implants

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M.V. Oliveira

2002-09-01

Full Text Available Powder metallurgy techniques have been used to produce controlled porous structures, such as the porous coatings applied for dental and orthopedic surgical implants, which allow bony tissue ingrowth within the implant surface improving fixation. This work presents the processing and characterization of titanium porous coatings of different porosity levels, processed through powder metallurgy techniques. Pure titanium sponge powders were used for coating and Ti-6Al7Nb powder metallurgy rods were used as substrates. Characterization was made through quantitative metallographic image analysis using optical light microscope for coating porosity data and SEM analysis for evaluation of the coating/substrate interface integrity. The results allowed optimization of the processing parameters in order to obtain porous coatings that meet the requirements for use as implants.

Long-term evaluation of hollow screw and hollow cylinder dental implants : Clinical and radiographic results after 10 years

NARCIS (Netherlands)

Telleman, Gerdien; Meijer, Henny J. A.; Raghoebar, Gerry M.

Background: In 1988, an implant manufacturer offered a new dental implant system, with a wide choice of hollow cylinder (HC) and hollow screw (HS) implants. The purpose of this retrospective study of HS and HC implants was to evaluate clinical and radiographic parameters of peri-implant tissue and

Evaluation of primary and secondary stability of titanium implants using different surgical techniques

NARCIS (Netherlands)

Tabassum, A.; Meijer, G.J.; Walboomers, X.F.; Jansen, J.A.

2014-01-01

OBJECTIVE: To investigate the influence of different surgical techniques on the primary and secondary implant stability using trabecular bone of goats as an implantation model. MATERIAL AND METHODS: In the iliac crest of eight goats, 48 cylindrical-screw-type implants with a diameter of 4.2 mm

Experimental conical-head abutment screws on the microbial leakage through the implant-abutment interface: an in vitro analysis using target-specific DNA probes.

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Pita, Murillo S; do Nascimento, Cássio; Dos Santos, Carla G P; Pires, Isabela M; Pedrazzi, Vinícius

2017-07-01

The aim of this in vitro study was to identify and quantify up to 38 microbial species from human saliva penetrating through the implant-abutment interface in two different implant connections, external hexagon and tri-channel internal connection, both with conventional flat-head or experimental conical-head abutment screws. Forty-eight two-part implants with external hexagon (EH; n = 24) or tri-channel internal (TI; n = 24) connections were investigated. Abutments were attached to implants with conventional flat-head or experimental conical-head screws. After saliva incubation, Checkerboard DNA-DNA hybridization was used to identify and quantify up to 38 bacterial colonizing the internal parts of the implants. Kruskal-Wallis test followed by Bonferroni's post-tests for multiple comparisons was used for statistical analysis. Twenty-four of thirty-eight species, including putative periodontal pathogens, were found colonizing the inner surfaces of both EH and TI implants. Peptostreptococcus anaerobios (P = 0.003), Prevotella melaninogenica (P abutment screws have impacted the microbial leakage through the implant-abutment interface. Implants attached with experimental conical-head abutment screws showed lower counts of microorganisms when compared with conventional flat-head screws. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Evaluation of Functionalized Porous Titanium Implants for Enhancing Angiogenesis in Vitro

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Laura Roland

2016-04-01

Full Text Available Implant constructs supporting angiogenesis are favorable for treating critically-sized bone defects, as ingrowth of capillaries towards the center of large defects is often insufficient. Consequently, the insufficient nutritional supply of these regions leads to impaired bone healing. Implants with specially designed angiogenic supporting geometry and functionalized with proangiogenic cytokines can enhance angiogenesis. In this study, Vascular Endothelial Growth Factor (VEGF and High Mobility Group Box 1 (HMGB1 were used for incorporation into poly-ε-caprolactone (PCL-coated porous titanium implants. Bioactivity of released factors and influence on angiogenesis of functionalized implants were evaluated using a migration assay and angiogenesis assays. Both implants released angiogenic factors, inducing migration of endothelial cells. Also, VEGF-functionalized PCL-coated titanium implants enhanced angiogenesis in vitro. Both factors were rapidly released in high doses from the implant coating during the first 72 h.

Influence of the implant abutment types and the dynamic loading on initial screw loosening

Science.gov (United States)

Kim, Eun-Sook

2013-01-01

PURPOSE This study examined the effects of the abutment types and dynamic loading on the stability of implant prostheses with three types of implant abutments prepared using different fabrication methods by measuring removal torque both before and after dynamic loading. MATERIALS AND METHODS Three groups of abutments were produced using different types of fabrication methods; stock abutment, gold cast abutment, and CAD/CAM custom abutment. A customized jig was fabricated to apply the load at 30° to the long axis. The implant fixtures were fixed to the jig, and connected to the abutments with a 30 Ncm tightening torque. A sine curved dynamic load was applied for 105 cycles between 25 and 250 N at 14 Hz. Removal torque before loading and after loading were evaluated. The SPSS was used for statistical analysis of the results. A Kruskal-Wallis test was performed to compare screw loosening between the abutment systems. A Wilcoxon signed-rank test was performed to compare screw loosening between before and after loading in each group (α=0.05). RESULTS Removal torque value before loading and after loading was the highest in stock abutment, which was then followed by gold cast abutment and CAD/CAM custom abutment, but there were no significant differences. CONCLUSION The abutment types did not have a significant influence on short term screw loosening. On the other hand, after 105 cycles dynamic loading, CAD/CAM custom abutment affected the initial screw loosening, but stock abutment and gold cast abutment did not. PMID:23509006

Assessment of a polyelectrolyte multilayer film coating loaded with BMP-2 on titanium and PEEK implants in the rabbit femoral condyle

Science.gov (United States)

Guillot, R.; Pignot-Paintrand, I.; Lavaud, J.; Decambron, A.; Bourgeois, E.; Josserand, V.; Logeart-Avramoglou, D.; Viguier, E.; Picart, C.

2016-01-01

The aim of this study was to evaluate the osseointegration of titanium implants (Ti-6Al-4V, noted here TA6V) and poly(etheretherketone) PEEK implants induced by a BMP-2-delivering surface coating made of polyelectrolyte multilayer films. The in vitro bioactivity of the polyelectrolyte film-coated implants was assessed using the alkaline phosphatase assay. BMP-2-coated TA6V and PEEK implants with a total dose of 9.3 µg of BMP-2 were inserted into the femoral condyles of New Zealand white rabbits and compared to uncoated implants. Rabbits were sacrificed 4 and 8 weeks after implantation. Histomorphometric analyses on TA6V and PEEK implants and microcomputed tomography on PEEK implants revealed that the bone-to-implant contact and bone area around the implants were significantly lower for the BMP-2-coated implants than for the bare implants. This was confirmed by scanning electron microscopy imaging. This difference was more pronounced at 4 weeks in comparison to the 8-week time point. However, bone growth inside the hexagonal upper hollow cavity of the screws was higher in the case of the BMP-2 coated implants. Overall, this study shows that a high dose of BMP-2 leads to localized and temporary bone impairment, and that the dose of BMP-2 delivered at the surface of an implant needs to be carefully optimized. PMID:26965394

Electrochemical assessment of some titanium and stainless steel implant dental alloys

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Echevarría, A.

2003-12-01

Full Text Available Commercially pure titanium alloy, Ti-6Al-4V alloy and stainless steel screw implants were evaluated in both Ringer and synthetic saliva physiological solutions at body temperature by EIS (Electrochemical Impedance Spectroscopy with immersion times of 30 d. Results were simulated as a "sandwich system" composed by four capacitors-resistances connected in series with the solution resistance. A model explaining the results in terms of the porosity and thickness of four different layers, was proposed.

Se utilizó la técnica de la Espectroscopia de Impedancia Electroquímica para evaluar en soluciones fisiológicas artificiales (Ringer y saliva sintética muestras extraídas de tornillos de implantes dentales certificados de titanio comercialmente puro, aleación Ti-6Al-W y acero inoxidable a temperatura corporal, con tiempos de inmersión hasta de 30 d. Los resultados se simularon mediante un modelo del tipo sandwich de cuatro elementos RC, conectados en serie con una resistencia de la solución. A partir de de esta simulación, se propone un modelo que explica los resultados obtenidos en términos de la evolución de la porosidad y el espesor de cuatro diferentes capas que se desarrollan en la superficie de los materiales evaluados.

Investigation of corrosion and ion release from titanium dental implant

International Nuclear Information System (INIS)

Ektessabi, A.M.; Mouhyi, J.; Louvette, P.; Sennerby, L.

1997-01-01

A thin passive titanium dioxide, in its stoichiometric form, has a very high corrosion resistance, but the same conclusion can not be made on corrosion resistance of a surface which is not stoichiometrically titanium dioxide, or even a surface which is a composition of various elements and oxides. In practice, the implants available on the market have an oxide surface contaminated with other elements. The aim of this paper is to correlate clinical observations that show the deterioration of Ti made implants after certain period of insertion in the patients, and in vitro corrosion resistance of Ti implants with surface passive oxide layer. For this purpose, surface analysis of the retrieved failed implants were performed and in vivo animal experiments with relation to ion release from implants were done. Finally, on the basis of the clinical observation, in vivo animal test, and in vitro electrochemical corrosion test, a model is proposed to explain the corrosion and ion release from the Ti implant. (author)

Effect of lubricant on the reliability of dental implant abutment screw joint: An in vitro laboratory and three-dimension finite element analysis.

Science.gov (United States)

Wu, Tingting; Fan, Hongyi; Ma, Ruiyang; Chen, Hongyu; Li, Zhi; Yu, Haiyang

2017-06-01

Biomechanical factors play a key role in the success of dental implants. Fracture and loosening of abutment screws are major issues. This study investigated the effect of lubricants on the stability of dental implant-abutment connection. As lubricants, graphite and vaseline were coated on the abutment screw surface, respectively, and a blank without lubricant served as the control. The total friction coefficient (μ tot ), clamping force, fatigue behavior and detorque of the joint combined with dynamic cyclic loading were measured under different lubricating conditions. Further, a three-dimensional finite element analysis was used to investigate stress distribution, in conjunction with experimental images. The results showed that the lubricant reduced μ tot , which in turn led to an increase in clamping force. Decrease in loading increased the fatigue life of the screw. However, use of lubricant at high load reduced the fatigue life. Ductile fracture at the first thread of the screw was the chief failure mode, which was due to maximum von Mises stress. Higher stress levels occurred in the lubricant groups. Lubricated screws resulted in lower detorque which made the joint easier to loosen. In conclusion, the lubricant cannot effectively improve the reliability of dental implant-abutment connection. Keeping the interfaces of implant-screw uncontaminated and strengthening the surface of the screw may be recommend for clinical operation and future design. Copyright © 2016 Elsevier B.V. All rights reserved.

Microstructure of titanium-cement-lithium disilicate interface in CAD-CAM dental implant crowns: a three-dimensional profilometric analysis.

Science.gov (United States)

Cresti, Stefano; Itri, Angelo; Rebaudi, Alberto; Diaspro, Alberto; Salerno, Marco

2015-01-01

Peri-implantitis is an infection of the implant surface caused by adhesion of bacteria that generate bone resorption and sometimes even consequent implant loss. Both screw-retained and cemented fixed implants are affected. The purpose of this study is to investigate the morphological defects at the cemented interface between titanium abutment and ceramic crown, comparing different adhesive cements used to fill the marginal gap. Twelve computer-aided design-computer-aided manufacturing dental crowns were cemented to titanium abutments using three different resin composite cements. Sealed margins were polished using grommets with descending diamond particle size. Three groups of four crowns each were made according to the cement used, namely RelyX Unicem (3 M ESPE), Panavia F 2.0 (Kuraray), and NX3 (Nexus Kerr). Samples were analyzed using optical inspection, three-dimensional profilometry, and image analysis, including analysis of variance. Although RelyX showed significantly lower root mean square surface roughness (4.4 ± 1.5 μm) than that of NX3 (7.0 ± 2.9 μm), it showed no significant difference with Panavia (3.7 ± 1.5 μm). The marginal gap was significantly wider in Panavia (149 ± 108 μm) as compared with NX3 (71 ± 45 μm) and Relyx (64 ± 34 μm). For all groups, homogeneous heights of both metal-cement and ceramic-cement gaps were observed. Moreover, all samples showed homogeneity of the margins and absence of instrumental bias, thus validating both procedure and materials. When using the chosen polishing method, RelyX Unicem showed both low roughness and marginal width, and thus the smoothest and more continuous abutment-crown interlayer, promising a low probability of occurrence of peri-implantitis. © 2013 Wiley Periodicals, Inc.

Tardive Dyskinesia, Oral Parafunction, and Implant-Supported Rehabilitation

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S. Lumetti

2016-01-01

Full Text Available Oral movement disorders may lead to prosthesis and implant failure due to excessive loading. We report on an edentulous patient suffering from drug-induced tardive dyskinesia (TD and oral parafunction (OP rehabilitated with implant-supported screw-retained prostheses. The frequency and intensity of the movements were high, and no pharmacological intervention was possible. Moreover, the patient refused night-time splint therapy. A series of implant and prosthetic failures were experienced. Implant failures were all in the maxilla and stopped when a rigid titanium structure was placed to connect implants. Ad hoc designed studies are desirable to elucidate the mutual influence between oral movement disorders and implant-supported rehabilitation.

Tardive Dyskinesia, Oral Parafunction, and Implant-Supported Rehabilitation.

Science.gov (United States)

Lumetti, S; Ghiacci, G; Macaluso, G M; Amore, M; Galli, C; Calciolari, E; Manfredi, E

2016-01-01

Oral movement disorders may lead to prosthesis and implant failure due to excessive loading. We report on an edentulous patient suffering from drug-induced tardive dyskinesia (TD) and oral parafunction (OP) rehabilitated with implant-supported screw-retained prostheses. The frequency and intensity of the movements were high, and no pharmacological intervention was possible. Moreover, the patient refused night-time splint therapy. A series of implant and prosthetic failures were experienced. Implant failures were all in the maxilla and stopped when a rigid titanium structure was placed to connect implants. Ad hoc designed studies are desirable to elucidate the mutual influence between oral movement disorders and implant-supported rehabilitation.

The role of prosthetic abutment material on the stress distribution in a maxillary single implant-supported fixed prosthesis

Energy Technology Data Exchange (ETDEWEB)

Peixoto, Hugo Eduardo, E-mail: hugo.e.peixoto@hotmail.com [Implantology Team, Latin American Institute of Research and Education in Dentistry, Curitiba, Paraná (Brazil); Bordin, Dimorvan, E-mail: dimorvan_bordin@hotmail.com [Department of Prosthodontics and Periodontology, Piracicaba Dental School, State University of Campinas, Limeira avenue, 901-Vila Rezende, Piracicaba, SP 13414-903 (Brazil); Del Bel Cury, Altair A., E-mail: altcury@fop.unicamp.br [Department of Prosthodontics and Periodontology, Piracicaba Dental School, State University of Campinas, Limeira avenue, 901-Vila Rezende, Piracicaba, SP 13414-903 (Brazil); Silva, Wander José da, E-mail: wanderjose@fop.unicamp.br [Department of Prosthodontics and Periodontology, Piracicaba Dental School, State University of Campinas, Limeira avenue, 901-Vila Rezende, Piracicaba, SP 13414-903 (Brazil); Faot, Fernanda, E-mail: fernanda.faot@gmail.com [Department of Restorative Dentistry, School of Dentistry, Federal University of Pelotas, Gonçalves Chaves, 457, 2nd floor, Pelotas, Rio Grande do Sul 96015-560 (Brazil)

2016-08-01

Purpose: Evaluate the influence of abutment's material and geometry on stress distribution in a single implant-supported prosthesis. Materials and Methods: Three-dimensional models were made based on tomographic slices of the upper middle incisor area, in which a morse taper implant was positioned and a titanium (Ti) or zirconia (ZrN) universal abutments was installed. The commercially available geometry of titanium (T) and zirconia (Z) abutments were used to draw two models, TM1 and ZM1 respectively, which served as control groups. These models were compared with 2 experimental groups were the mechanical properties of Z were applied to the titanium abutment (TM2) and vice versa for the zirconia abutment (ZM2). Subsequently, loading was simulated in two steps, starting with a preload phase, calculated with the respective friction coefficients of each materials, followed by a combined preload and chewing force. The maximum von Mises stress was described. Data were analyzed by two-way ANOVA that considered material composition, geometry and loading (p < 0.05). Results: Titanium and zirconia abutments showed similar von Mises stresses in the mechanical part of the four models. The area with the highest concentration of stress was the screw thread, following by the screw body. The highest stress levels occurred in screw thread was observed during the preloading phase in the ZM1 model (931 MPa); and during the combined loading in the TM1 model (965 MPa). Statistically significant differences were observed for loading, the material × loading interaction, and the loading × geometry interaction (p < 0.05). Preloading contributed for 77.89% of the stress (p < 0.05). There were no statistically significant differences to the other factors (p > 0.05). Conclusion: The screw was the piece most intensely affected, mainly through the preload force, independent of the abutment's material. - Highlights: • The abutment's screw was the most impaired piece of the

Insertion profiles of 4 headless compression screws.

Science.gov (United States)

Hart, Adam; Harvey, Edward J; Lefebvre, Louis-Philippe; Barthelat, Francois; Rabiei, Reza; Martineau, Paul A

2013-09-01

In practice, the surgeon must rely on screw position (insertion depth) and tactile feedback from the screwdriver (insertion torque) to gauge compression. In this study, we identified the relationship between interfragmentary compression and these 2 factors. The Acutrak Standard, Acutrak Mini, Synthes 3.0, and Herbert-Whipple implants were tested using a polyurethane foam scaphoid model. A specialized testing jig simultaneously measured compression force, insertion torque, and insertion depth at half-screw-turn intervals until failure occurred. The peak compression occurs at an insertion depth of -3.1 mm, -2.8 mm, 0.9 mm, and 1.5 mm for the Acutrak Mini, Acutrak Standard, Herbert-Whipple, and Synthes screws respectively (insertion depth is positive when the screw is proud above the bone and negative when buried). The compression and insertion torque at a depth of -2 mm were found to be 113 ± 18 N and 0.348 ± 0.052 Nm for the Acutrak Standard, 104 ± 15 N and 0.175 ± 0.008 Nm for the Acutrak Mini, 78 ± 9 N and 0.245 ± 0.006 Nm for the Herbert-Whipple, and 67 ± 2N, 0.233 ± 0.010 Nm for the Synthes headless compression screws. All 4 screws generated a sizable amount of compression (> 60 N) over a wide range of insertion depths. The compression at the commonly recommended insertion depth of -2 mm was not significantly different between screws; thus, implant selection should not be based on compression profile alone. Conically shaped screws (Acutrak) generated their peak compression when they were fully buried in the foam whereas the shanked screws (Synthes and Herbert-Whipple) reached peak compression before they were fully inserted. Because insertion torque correlated poorly with compression, surgeons should avoid using tactile judgment of torque as a proxy for compression. Knowledge of the insertion profile may improve our understanding of the implants, provide a better basis for comparing screws, and enable the surgeon to optimize compression. Copyright �

Coating dental implant abutment screws with diamondlike carbon doped with diamond nanoparticles: the effect on maintaining torque after mechanical cycling.

Science.gov (United States)

Lepesqueur, Laura Soares; de Figueiredo, Viviane Maria Gonçalves; Ferreira, Leandro Lameirão; Sobrinho, Argemiro Soares da Silva; Massi, Marcos; Bottino, Marco Antônio; Nogueira Junior, Lafayette

2015-01-01

To determine the effect of maintaining torque after mechanical cycling of abutment screws that are coated with diamondlike carbon and coated with diamondlike carbon doped with diamond nanoparticles, with external and internal hex connections. Sixty implants were divided into six groups according to the type of connection (external or internal hex) and the type of abutment screw (uncoated, coated with diamondlike carbon, and coated with diamondlike carbon doped with diamond nanoparticles). The implants were inserted into polyurethane resin and crowns of nickel chrome were cemented on the implants. The crowns had a hole for access to the screw. The initial torque and the torque after mechanical cycling were measured. The torque values maintained (in percentages) were evaluated. Statistical analysis was performed using one-way analysis of variance and the Tukey test, with a significance level of 5%. The largest torque value was maintained in uncoated screws with external hex connections, a finding that was statistically significant (P = .0001). No statistically significant differences were seen between the groups with and without coating in maintaining torque for screws with internal hex connections (P = .5476). After mechanical cycling, the diamondlike carbon with and without diamond doping on the abutment screws showed no improvement in maintaining torque in external and internal hex connections.

Clinical evidence on titanium-zirconium dental implants: a systematic review and meta-analysis.

Science.gov (United States)

Altuna, P; Lucas-Taulé, E; Gargallo-Albiol, J; Figueras-Álvarez, O; Hernández-Alfaro, F; Nart, J

2016-07-01

The use of titanium implants is well documented and they have high survival and success rates. However, when used as reduced-diameter implants, the risk of fracture is increased. Narrow diameter implants (NDIs) of titanium-zirconium (Ti-Zr) alloy have recently been developed (Roxolid; Institut Straumann AG). Ti-Zr alloys (two highly biocompatible materials) demonstrate higher tensile strength than commercially pure titanium. The aim of this systematic review was to summarize the existing clinical evidence on dental NDIs made from Ti-Zr. A systematic literature search was performed using the Medline database to find relevant articles on clinical studies published in the English language up to December 2014. Nine clinical studies using Ti-Zr implants were identified. Overall, 607 patients received 922 implants. The mean marginal bone loss was 0.36±0.06mm after 1 year and 0.41±0.09mm after 2 years. The follow-up period ranged from 3 to 36 months. Mean survival and success rates were 98.4% and 97.8% at 1 year after implant placement and 97.7% and 97.3% at 2 years. Narrow diameter Ti-Zr dental implants show survival and success rates comparable to regular diameter titanium implants (>95%) in the short term. Long-term follow-up clinical data are needed to confirm the excellent clinical performance of these implants. Copyright © 2016 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Alveolar Ridge Reconstruction with Titanium Meshes and Simultaneous Implant Placement: A Retrospective, Multicenter Clinical Study

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Raquel Zita Gomes

2016-01-01

Full Text Available Objective. To evaluate horizontal bone gain and implant survival and complication rates in patients treated with titanium meshes placed simultaneously with dental implants and fixed over them. Methods. Twenty-five patients treated with 40 implants and simultaneous guided bone regeneration with titanium meshes (i–Gen®, MegaGen, Gyeongbuk, Republic of Korea were selected for inclusion in the present retrospective multicenter study. Primary outcomes were horizontal bone gain and implant survival; secondary outcomes were biological and prosthetic complications. Results. After the removal of titanium meshes, the CBCT evaluation revealed a mean horizontal bone gain of 3.67 mm (±0.89. The most frequent complications were mild postoperative edema (12/25 patients: 48% and discomfort after surgery (10/25 patients: 40%; these complications were resolved within one week. Titanium mesh exposure occurred in 6 patients (6/25 : 24%: one of these suffered partial loss of the graft and another experienced complete graft loss and implant failure. An implant survival rate of 97.5% (implant-based and a peri-implant marginal bone loss of 0.43 mm (±0.15 were recorded after 1 year. Conclusions. The horizontal ridge reconstruction with titanium meshes placed simultaneously with dental implants achieved predictable satisfactory results. Prospective randomized controlled trials on a larger sample of patients are required to validate these positive outcomes.

Comparison of surface modified zirconia implants with commercially available zirconium and titanium implants: a histological study in pigs.

Science.gov (United States)

Gredes, Tomasz; Kubasiewicz-Ross, Pawel; Gedrange, Tomasz; Dominiak, Marzena; Kunert-Keil, Christiane

2014-08-01

New biomaterials and their various surface modifications should undergo in vitro and in vivo evaluation before clinical trials. The objective of our in vivo study was to evaluate the biocompatibility of newly created zirconium implant surfaces after implantation in the lower jaw of pigs and compare the osseointegration of these dental implants with commercially available zirconium and titanium implants. After a healing period of 12 weeks, a histological analysis of the soft and hard tissues and a histomorphometric analysis of the bone-implant contact (BIC) were performed. The implant surfaces showed an intimate connection to the adjacent bone for all tested implants. The 3 newly created zirconium implant surfaces achieved a BIC of 45% on average in comparison with a BIC of 56% from the reference zirconium implants and 35% from titanium implants. Furthermore, the new zirconium implants had a better attachment to gingival and bone tissues in the range of implant necks as compared with the reference implants. The results suggest that the new implants comparably osseointegrate within the healing period, and they have a good in vivo biocompatibility.

In-vitro evaluation of corrosion resistance of nitrogen ion implanted titanium simulated body fluid

International Nuclear Information System (INIS)

Subbaiyan, M.; Sundararajian, T.; Rajeswari, S.; Kamachi Mudali, U.; Nair, K.G.M.; Thampi, N.S.

1997-01-01

Titanium and its alloy Ti6Al4V enjoy widespread use in various biomedical applications because of favourable local tissue response, higher corrosion resistance and fatigue strength than the stainless steels and cobalt-chromium alloy previously used. The study reported in this paper aims to optimize the conditions of nitrogen ion implantation on commercially pure titanium and to correlate the implantation parameters to the corrosion resistance. X-ray photoelectron spectroscopy was used to analyse surface concentration and the implantation processes. An improvement in the electrochemical behaviour of the passive film was shown to occur with nitrogen ion implantation on titanium, in simulated body fluids. (UK)

Pectin nanocoating of titanium implant surfaces - an experimental study in rabbits

DEFF Research Database (Denmark)

Gurzawska, Katarzyna Aleksandra; Dirscherl, Kai; Jørgensen, Bodil

2017-01-01

that may increase adhesion of bone proteins, and bone cells at the implant surface. Nanocoating with pectins, plant cell wall-derived polysaccharides, is frequently done using rhamnogalacturonan-I (RG-I). AIM: The aim of the study was to evaluate the effect of nanocoating titanium implants with plant cell...... wall-derived rhamnogalacturonan-I, on bone healing and osseointegration. MATERIAL AND METHODS: Machined titanium implants were coated with three modifications of rhamnogalacturonan-I (RG-I). Chemical and physical surface properties were examined before insertion of nanocoated implants (n = 96....... The bone response to the nanocoated implants was analyzed qualitatively and quantitatively after 2, 4, 6, and 8 weeks of healing using light microscopy and histomorphometric methods. RESULTS: The RG-I coating influenced the surface chemical composition; wettability and roughness, making the surface more...

Osseointegration of zirconia implants: an SEM observation of the bone-implant interface.

Science.gov (United States)

Depprich, Rita; Zipprich, Holger; Ommerborn, Michelle; Mahn, Eduardo; Lammers, Lydia; Handschel, Jörg; Naujoks, Christian; Wiesmann, Hans-Peter; Kübler, Norbert R; Meyer, Ulrich

2008-11-06

The successful use of zirconia ceramics in orthopedic surgery led to a demand for dental zirconium-based implant systems. Because of its excellent biomechanical characteristics, biocompatibility, and bright tooth-like color, zirconia (zirconium dioxide, ZrO2) has the potential to become a substitute for titanium as dental implant material. The present study aimed at investigating the osseointegration of zirconia implants with modified ablative surface at an ultrastructural level. A total of 24 zirconia implants with modified ablative surfaces and 24 titanium implants all of similar shape and surface structure were inserted into the tibia of 12 Göttinger minipigs. Block biopsies were harvested 1 week, 4 weeks or 12 weeks (four animals each) after surgery. Scanning electron microscopy (SEM) analysis was performed at the bone implant interface. Remarkable bone attachment was already seen after 1 week which increased further to intimate bone contact after 4 weeks, observed on both zirconia and titanium implant surfaces. After 12 weeks, osseointegration without interposition of an interfacial layer was detected. At the ultrastructural level, there was no obvious difference between the osseointegration of zirconia implants with modified ablative surfaces and titanium implants with a similar surface topography. The results of this study indicate similar osseointegration of zirconia and titanium implants at the ultrastructural level.

Anodization: a promising nano-modification technique of titanium implants for orthopedic applications.

Science.gov (United States)

Yao, Chang; Webster, Thomas J

2006-01-01

Anodization is a well-established surface modification technique that produces protective oxide layers on valve metals such as titanium. Many studies have used anodization to produce micro-porous titanium oxide films on implant surfaces for orthopedic applications. An additional hydrothermal treatment has also been used in conjunction with anodization to deposit hydroxyapatite on titanium surfaces; this is in contrast to using traditional plasma spray deposition techniques. Recently, the ability to create nanometer surface structures (e.g., nano-tubular) via anodization of titanium implants in fluorine solutions have intrigued investigators to fabricate nano-scale surface features that mimic the natural bone environment. This paper will present an overview of anodization techniques used to produce micro-porous titanium oxide structures and nano-tubular oxide structures, subsequent properties of these anodized titanium surfaces, and ultimately their in vitro as well as in vivo biological responses pertinent for orthopedic applications. Lastly, this review will emphasize why anodized titanium structures that have nanometer surface features enhance bone forming cell functions.

Microhardness of boron, titanium, and nitrogen implanted steel

International Nuclear Information System (INIS)

Sowa, M.; Szyszko, W.; Sielanko, J.; Glusiec, L.

1989-01-01

Mechanically polished steel (1H18N9T) and (15GTM) samples are implanted with boron, titanium, and nitrogen ions, with dose ranging from 10 16 to 10 17 ions/cm 2 . The implantation energy varied from 100 to 250 keV. Implanted samples are heat-treated at 400 to 800 0 C in vacuum. The microhardness of implanted samples is measured by using a Hanneman tester with loads ranging from 2 to 40 g. The influence of annealing temperature on microhardness of the implanted layers is determined. The diffusion of boron from the implanted layers is also investigated by using the secondary ion mass spectrometer. The diffusion coefficients of boron in steel are determined. (author)

Synthesis of titanium sapphire by ion implantation

International Nuclear Information System (INIS)

Morpeth, L.D.; McCallum, J.C.; Nugent, K.W.

1998-01-01

Since laser action was first demonstrated in titanium sapphire (Ti:Al 2 O 3 ) in 1982, it has become the most widely used tunable solid state laser source. The development of a titanium sapphire laser in a waveguide geometry would yield an elegant, compact, versatile and highly tunable light source useful for applications in many areas including optical telecommunications. We are investigating whether ion implantation techniques can be utilised to produce suitable crystal quality and waveguide geometry for fabrication of a Ti:Al 2 O 3 waveguide laser. The implantation of Ti and O ions into c-axis oriented α-Al 2 O 3 followed by subsequent thermal annealing under various conditions has been investigated as a means of forming the waveguide and optimising the fraction of Ti ions that have the correct oxidation state required for laser operation. A Raman Microprobe is being used to investigate the photo-luminescence associated with Ti 3+ ion. Initial photoluminescence measurements of ion implanted samples are encouraging and reveal a broad luminescence profile over a range of ∼ .6 to .9 μm, similar to that expected from Ti 3+ . Rutherford Backscattering and Ion Channelling analysis have been used to study the crystal structure of the samples following implantation and annealing. This enables optimisation of the implantation parameters and annealing conditions to minimise defect levels which would otherwise limit the ability of light to propagate in the Ti:Al 2O 3 waveguide. (authors)

Comparison of mechanical and biological properties of zirconia and titanium alloy orthodontic micro-implants.

Science.gov (United States)

Choi, Hae Won; Park, Young Seok; Chung, Shin Hye; Jung, Min Ho; Moon, Won; Rhee, Sang Hoon

2017-07-01

The aim of this study was to compare the initial stability as insertion and removal torque and the clinical applicability of novel orthodontic zirconia micro-implants made using a powder injection molding (PIM) technique with those parameters in conventional titanium micro-implants. Sixty zirconia and 60 titanium micro-implants of similar design (diameter, 1.6 mm; length, 8.0 mm) were inserted perpendicularly in solid polyurethane foam with varying densities of 20 pounds per cubic foot (pcf), 30 pcf, and 40 pcf. Primary stability was measured as maximum insertion torque (MIT) and maximum removal torque (MRT). To investigate clinical applicability, compressive and tensile forces were recorded at 0.01, 0.02, and 0.03 mm displacement of the implants at angles of 0°, 10°, 20°, 30°, and 40°. The biocompatibility of zirconia micro-implants was assessed via an experimental animal study. There were no statistically significant differences between zirconia micro-implants and titanium alloy implants with regard to MIT, MRT, or the amount of movement in the angulated lateral displacement test. As angulation increased, the mean compressive and tensile forces required to displace both types of micro-implants increased substantially at all distances. The average bone-to-implant contact ratio of prototype zirconia micro-implants was 56.88 ± 6.72%. Zirconia micro-implants showed initial stability and clinical applicability for diverse orthodontic treatments comparable to that of titanium micro-implants under compressive and tensile forces.

Numerical simulation of in vivo intraosseous torsional failure of a hollow-screw oral implant

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Akca Kivanc

2006-11-01

Full Text Available Abstract Background Owing to the complexity and magnitude of functional forces transferred to the bone-implant interface, the mechanical strength of the interface is of great importance. The purpose of this study was to determine the intraosseous torsional shear strength of an osseointegrated oral implant using 3-D finite element (FE stress analysis implemented by in vivo failure torque data of an implant. Methods A Ø 3.5 mm × 12 mm ITI® hollow screw dental implant in a patient was subjected to torque failure test using a custom-made strain-gauged manual torque wrench connected to a data acquisition system. The 3-D FE model of the implant and peri-implant circumstances was constructed. The in vivo strain data was converted to torque units (N.cm to involve in loading definition of FE analysis. Upon processing of the FE analysis, the shear stress of peri-implant bone was evaluated to assume torsional shear stress strength of the bone-implant interface. Results The in vivo torque failure test yielded 5952 μstrains at custom-made manual torque wrench level and conversion of the strain data resulted in 750 N.cm. FE revealed that highest shear stress value in the trabecular bone, 121 MPa, was located at the first intimate contact with implant. Trabecular bone in contact with external surface of hollow implant body participated shear stress distribution, but not the bone resting inside of the hollow. Conclusion The torsional strength of hollow-screw implants is basically provided by the marginal bone and the hollow part has negligible effect on interfacial shear strength.

In vitro biological outcome of laser application for modification or processing of titanium dental implants.

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Hindy, Ahmed; Farahmand, Farzam; Tabatabaei, Fahimeh Sadat

2017-07-01

There are numerous functions for laser in modern implant dentistry including surface treatment, surface coating, and implant manufacturing. As laser application may potentially improve osseointegration of dental implants, we systematically reviewed the literature for in vitro biological responses to laser-modified or processed titanium dental implants. The literature was searched in PubMed, ISI Web, and Scopus, using keywords "titanium dental implants," "laser," "biocompatibility," and their synonyms. After screening the 136 references obtained, 28 articles met the inclusion criteria. We found that Nd:YAG laser was the most commonly used lasers in the treatment or processing of titanium dental implants. Most of the experiments used cell attachment and cell proliferation to investigate bioresponses of the implants. The most commonly used cells in these assays were osteoblast-like cells. Only one study was conducted in stem cells. These in vitro studies reported higher biocompatibility in laser-modified titanium implants. It seems that laser radiation plays a vital role in cell response to dental implants; however, it is necessary to accomplish more studies using different laser types and parameters on various cells to offer a more conclusive result.

Interruption of Electrical Conductivity of Titanium Dental Implants Suggests a Path Towards Elimination Of Corrosion.

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Pozhitkov, Alex E; Daubert, Diane; Brochwicz Donimirski, Ashley; Goodgion, Douglas; Vagin, Mikhail Y; Leroux, Brian G; Hunter, Colby M; Flemmig, Thomas F; Noble, Peter A; Bryers, James D

2015-01-01

Peri-implantitis is an inflammatory disease that results in the destruction of soft tissue and bone around the implant. Titanium implant corrosion has been attributed to the implant failure and cytotoxic effects to the alveolar bone. We have documented the extent of titanium release into surrounding plaque in patients with and without peri-implantitis. An in vitro model was designed to represent the actual environment of an implant in a patient's mouth. The model uses actual oral microbiota from a volunteer, allows monitoring electrochemical processes generated by biofilms growing on implants and permits control of biocorrosion electrical current. As determined by next generation DNA sequencing, microbial compositions in experiments with the in vitro model were comparable with the compositions found in patients with implants. It was determined that the electrical conductivity of titanium implants was the key factor responsible for the biocorrosion process. The interruption of the biocorrosion current resulted in a 4-5 fold reduction of corrosion. We propose a new design of dental implant that combines titanium in zero oxidation state for osseointegration and strength, interlaid with a nonconductive ceramic. In addition, we propose electrotherapy for manipulation of microbial biofilms and to induce bone healing in peri-implantitis patients.

Interruption of Electrical Conductivity of Titanium Dental Implants Suggests a Path Towards Elimination Of Corrosion.

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Alex E Pozhitkov

Full Text Available Peri-implantitis is an inflammatory disease that results in the destruction of soft tissue and bone around the implant. Titanium implant corrosion has been attributed to the implant failure and cytotoxic effects to the alveolar bone. We have documented the extent of titanium release into surrounding plaque in patients with and without peri-implantitis. An in vitro model was designed to represent the actual environment of an implant in a patient's mouth. The model uses actual oral microbiota from a volunteer, allows monitoring electrochemical processes generated by biofilms growing on implants and permits control of biocorrosion electrical current. As determined by next generation DNA sequencing, microbial compositions in experiments with the in vitro model were comparable with the compositions found in patients with implants. It was determined that the electrical conductivity of titanium implants was the key factor responsible for the biocorrosion process. The interruption of the biocorrosion current resulted in a 4-5 fold reduction of corrosion. We propose a new design of dental implant that combines titanium in zero oxidation state for osseointegration and strength, interlaid with a nonconductive ceramic. In addition, we propose electrotherapy for manipulation of microbial biofilms and to induce bone healing in peri-implantitis patients.

Cranioplasty Enhanced by Three-Dimensional Printing: Custom-Made Three-Dimensional-Printed Titanium Implants for Skull Defects.

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Park, Eun-Kyung; Lim, Jun-Young; Yun, In-Sik; Kim, Ju-Seong; Woo, Su-Heon; Kim, Dong-Seok; Shim, Kyu-Won

2016-06-01

The authors studied to demonstrate the efficacy of custom-made three-dimensional (3D)-printed titanium implants for reconstructing skull defects. From 2013 to 2015, 21 patients (8-62 years old, mean = 28.6-year old; 11 females and 10 males) with skull defects were treated. Total disease duration ranged from 6 to 168 months (mean = 33.6 months). The size of skull defects ranged from 84 × 104 to 154 × 193 mm. Custom-made implants were manufactured by Medyssey Co, Ltd (Jecheon, South Korea) using 3D computed tomography data, Mimics software, and an electron beam melting machine. The team reviewed several different designs and simulated surgery using a 3D skull model. During the operation, the implant was fit to the defect without dead space. Operation times ranged from 85 to 180 minutes (mean = 115.7 minutes). Operative sites healed without any complications except for 1 patient who had red swelling with exudation at the skin defect, which was a skin infection and defect at the center of the scalp flap reoccurring since the initial head injury. This patient underwent reoperation for skin defect revision and replacement of the implant. Twenty-one patients were followed for 6 to 24 months (mean = 14.1 months). The patients were satisfied and had no recurrent wound problems. Head computed tomography after operation showed good fixation of titanium implants and satisfactory skull-shape symmetry. For the reconstruction of skull defects, the use of autologous bone grafts has been the treatment of choice. However, bone use depends on availability, defect size, and donor morbidity. As 3D printing techniques are further advanced, it is becoming possible to manufacture custom-made 3D titanium implants for skull reconstruction.

Fracture strength and failure mode of maxillary implant-supported provisional single crowns: a comparison of composite resin crowns fabricated directly over PEEK abutments and solid titanium abutments.

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Santing, Hendrik Jacob; Meijer, Henny J A; Raghoebar, Gerry M; Özcan, Mutlu

2012-12-01

Polyetheretherketone (PEEK) temporary abutments have been recently introduced for making implant-supported provisional single crowns. Little information is available in the dental literature on the durability of provisional implant-supported restorations. The objectives of this study were to evaluate the fracture strength of implant-supported composite resin crowns on PEEK and solid titanium temporary abutments, and to analyze the failure types. Three types of provisional abutments, RN synOcta Temporary Meso Abutment (PEEK; Straumann), RN synOcta Titanium Post for Temporary Restorations (Straumann), and Temporary Abutment Engaging NobRplRP (Nobel Biocare) were used, and provisional screw-retained crowns using composite resin (Solidex) were fabricated for four different locations in the maxilla. The specimens were tested in a universal testing machine at a crosshead speed of 1 mm/minute until fracture occurred. The failure types were analyzed and further categorized as irreparable (Type 1) or reparable (Type 2). No significant difference was found between different abutment types. Only for the position of the maxillary central incisor, composite resin crowns on PEEK temporary abutments showed significantly lower (p Provisional crowns on PEEK abutments showed similar fracture strength as titanium temporary abutments except for central incisors. Maxillary right central incisor composite resin crowns on PEEK temporary abutments fractured below the mean anterior masticatory loading forces reported to be approximately 206 N. © 2010 Wiley Periodicals, Inc.

The effect of hierarchical micro/nanosurface titanium implant on osseointegration in ovariectomized sheep.

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Xiao, J; Zhou, H; Zhao, L; Sun, Y; Guan, S; Liu, B; Kong, L

2011-06-01

Hydrofluoric etching and anodized hierarchical micro/nanotextured surface titanium implant was placed in mandibles of ovariectomized sheep for 12 weeks, and it showed improved osseointegration by resonance frequency analysis (RFA), microcomputed tomography (micro-CT) evaluation, histomorphometry, and biomechanical test. This study aimed to investigate the effects of micro/nanotextured titanium implant on osseointegration in ovariectomized (OVX) sheep. The hierarchical micro/nanotextured surface of titanium implant was fabricated by acid in 0.5% (w/v) hydrofluoric (HF) and anodized in HF acid electrolytes with a DC power of 20 V, and the machined surface implants with no treatment served as control group. The implants were placed in mandibles of OVX sheep, respectively. Twelve weeks after implantation, RFA, microcomputed tomography, histomorphometry, and biomechanical tests were applied to detect the osseointegration of the two groups. The implant stability quotient (ISQ) values, the maximum pull-out forces, and the bone-implant contact (BIC) were 65.5 ± 6.3, 490.6 ± 72.7 N, and 58.31 ± 5.79% in the micro/nanogroup and 58.3 ± 8.9, 394.5 ± 54.5 N, and 46.85 ± 5.04% in the control group, respectively. There was no significant difference between the two groups in ISQ values (p > 0.05), but in the micro/nanogroup, the maximal pull-out force and the BIC were increased significantly (p Micro-CT analysis showed that the bone volume ratio and the trabecular number increased significantly (p micro/nanogroup. Implant modification by HF acid etching and anodization to form a hierarchical micro/nanotextured surface could improve titanium implant osseointegration in OVX sheep 12 weeks after implantation.

The Redox Balance in Erythrocytes, Plasma, and Periosteum of Patients with Titanium Fixation of the Jaw

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Jan Borys

2017-06-01

Full Text Available Titanium miniplates and screws are commonly used for fixation of jaw fractured or osteotomies. Despite the opinion of their biocompatibility, in clinical practice symptoms of chronic inflammation around the fixation develop in some patients, even many years after the application of miniplates and screws. The cause of these complications is still an unanswered question. Taking into account that oxidative stress is one of the toxic action of titanium, we have evaluated the antioxidant barrier as well as oxidative stress in the erythrocytes, plasma and periosteum covering the titanium fixation of the jaw. The study group was composed of 32 patients aged 20–30 with inserted miniplates and screws. The antioxidant defense: catalase (CAT, glutathione peroxidase (GPx, superoxide dismutase-1 (SOD1, uric acid (UA, total antioxidant capacity (TAC, as well as oxidative damage products: advanced oxidation protein products (AOPP, advanced glycation end products (AGE, dityrosine, kynurenine, N-formylkynurenine, tryptophan, malondialdehyde (MDA, 4-hydroxynonenal (4-HNE, total oxidant status (TOS, and oxidative status index (OSI were evaluated. SOD1 activity (↓37%, and tryptophan levels (↓34% showed a significant decrease while AOPP (↑25%, TOS (↑80% and OSI (↑101% were significantly elevated in maxillary periosteum of patients who underwent bimaxillary osteotomies as compared to the control group. SOD-1 (↓55%, TAC (↓58.6%, AGE (↓60% and N-formylkynurenine (↓34% was statistically reduced while AOPP (↑38%, MDA (↑29%, 4-HNE (↑114%, TOS (↑99%, and OSI (↑381% were significantly higher in the mandibular periosteum covering miniplates/screw compared with the control tissues. There were no correlations between antioxidants and oxidative stress markers in the periosteum of all patients and the blood. As exposure to the Ti6Al4V titanium alloy leads to disturbances of redox balance in the periosteum surrounding titanium implants of the maxilla

Decontamination of titanium implant surface and re-osseointegration to treat peri-implantitis: a literature review

NARCIS (Netherlands)

Subramani, K.; Wismeijer, D.

2012-01-01

PURPOSE: To review the literature on decontamination of titanium implant surfaces following peri-implantitis and the effect of various cleaning methods on re-osseointegration. MATERIALS AND METHODS: An electronic search of the literature at PubMed was conducted on the studies published between 1966

Development of a DIPG Orthotopic Model in Mice Using an Implantable Guide-Screw System.

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Miguel Marigil

Full Text Available In this work we set to develop and to validate a new in vivo frameless orthotopic Diffuse Intrinsic Pontine Glioma (DIPG model based in the implantation of a guide-screw system.It consisted of a guide-screw also called bolt, a Hamilton syringe with a 26-gauge needle and an insulin-like 15-gauge needle. The guide screw is 2.6 mm in length and harbors a 0.5 mm central hole which accepts the needle of the Hamilton syringe avoiding a theoretical displacement during insertion. The guide-screw is fixed on the mouse skull according to the coordinates: 1mm right to and 0.8 mm posterior to lambda. To reach the pons the Hamilton syringe is adjusted to a 6.5 mm depth using a cuff that serves as a stopper. This system allows delivering not only cells but also any kind of intratumoral chemotherapy, antibodies or gene/viral therapies.The guide-screw was successfully implanted in 10 immunodeficient mice and the animals were inoculated with DIPG human cell lines during the same anesthetic period. All the mice developed severe neurologic symptoms and had a median overall survival of 95 days ranging the time of death from 81 to 116 days. Histopathological analysis confirmed tumor into the pons in all animals confirming the validity of this model.Here we presented a reproducible and frameless DIPG model that allows for rapid evaluation of tumorigenicity and efficacy of chemotherapeutic or gene therapy products delivered intratumorally to the pons.

Nanocoating of titanium implant surfaces with organic molecules. Polysaccharides including glycosaminoglycans

DEFF Research Database (Denmark)

Gurzawska, Katarzyna Aleksandra; Svava, Rikke; Jørgensen, Niklas Rye

2012-01-01

Long-term stability of titanium implants are dependent on a variety of factors. Nanocoating with organic molecules is one of the method used to improve osseointegration. Nanoscale modification of titanium implants affects surface properties, such as hydrophilicity, biochemical bonding capacity...... and roughness. This influences cell behaviour on the surface such as adhesion, proliferation and differentiation of cells as well as the mineralization of the extracellular matrix at the implant surfaces. The aim of the present systematic review was to describe organic molecules used for surface nanocoating...... nanocoatings. The included in vivo studies, showed improvement of bone interface reactions measured as increased Bone-to-Implant Contact length and Bone Mineral Density adjacent to the polysaccharide coated surfaces. Based on existing literature, surface modification with polysaccharide and glycosaminoglycans...

Artefacts in multimodal imaging of titanium, zirconium and binary titanium–zirconium alloy dental implants: an in vitro study

Science.gov (United States)

Schöllchen, Maximilian; Aarabi, Ghazal; Assaf, Alexandre T; Rendenbach, Carsten; Beck-Broichsitter, Benedicta; Semmusch, Jan; Sedlacik, Jan; Heiland, Max; Fiehler, Jens; Siemonsen, Susanne

2017-01-01

Objectives: To analyze and evaluate imaging artefacts induced by zirconium, titanium and titanium–zirconium alloy dental implants. Methods: Zirconium, titanium and titanium–zirconium alloy implants were embedded in gelatin and MRI, CT and CBCT were performed. Standard protocols were used for each modality. For MRI, line–distance profiles were plotted to quantify the accuracy of size determination. For CT and CBCT, six shells surrounding the implant were defined every 0.5 cm from the implant surface and histogram parameters were determined for each shell. Results: While titanium and titanium–zirconium alloy induced extensive signal voids in MRI owing to strong susceptibility, zirconium implants were clearly definable with only minor distortion artefacts. For titanium and titanium–zirconium alloy, the MR signal was attenuated up to 14.1 mm from the implant. In CT, titanium and titanium–zirconium alloy resulted in less streak artefacts in comparison with zirconium. In CBCT, titanium–zirconium alloy induced more severe artefacts than zirconium and titanium. Conclusions: MRI allows for an excellent image contrast and limited artefacts in patients with zirconium implants. CT and CBCT examinations are less affected by artefacts from titanium and titanium–zirconium alloy implants compared with MRI. The knowledge about differences of artefacts through different implant materials and image modalities might help support clinical decisions for the choice of implant material or imaging device in the clinical setting. PMID:27910719

Design of three-dimensional visualization based on the posterior lumbar pedicle screw fixation

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Kai XU

2011-09-01

Full Text Available Objective To establish a three-dimensional visualization model of posterior lumbar pedicle screw fixation.Methods A patient with lumbar intervertebral disc hernia and another patient with compression fracture of lumbar vertebra were involved in the present study.Both patients underwent multi-slice spiral CT scan before and after lumbar pedicle screw fixation.The degree of preoperative vertebral compression,vertebral morphology before and after surgery,postoperative pedicle screw position,and decompression effects were observed.The original data of the multi-slice spiral CT were inputted into the computer.The three-dimensional reconstructed images of the lumbar and implanted screws were obtained using the software Amira 4.1 to show the three-dimensional shape of the lumbar vertebrae before and after surgery and the location of the implanted screws.Results The morphology and structure of the lumbar vertebrae before and after surgery and of the implanted screws were reconstructed using the digital navigation platform.The reconstructed 3D images could be displayed in multicolor,transparent,or arbitrary combinations.In the 3D surface reconstruction images,the location and structure of the implanted screws could be clearly observed,and the decompression of the spinal cord or nerve roots and the severity of the fracture and the compression of lumbar vertebrae could be fully evaluated.The reconstructed images before operation revealed the position of the vertebral pedicles and provided reference for intraoperative localization.Conclusions The three-dimensional computerized reconstructions of lumbar pedicle screw fixation may be valuable in basic research,clinical experiment,and surgical planning.The software Amira is one of the bases of three-dimensional reconstruction.

Comparison of the passivity between cast alloy and laser-welded titanium overdenture bars.

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Paiva, Jose; Givan, Daniel A; Broome, James C; Lemons, Jack E; McCracken, Michael S

2009-12-01

The purpose of this study was to investigate the fit of cast alloy overdenture and laser-welded titanium-alloy bars by measuring induced strain upon tightening of the bars on a master cast as well as a function of screw tightening sequence. Four implant analogs were secured into Type IV dental stone to simulate a mandibular edentulous patient cast, and two groups of four overdenture bars were fabricated. Group I was four cast alloy bars and Group II was four laser-welded titanium bars. The cast alloy bars included Au-Ag-Pd, Pd-Ag-Au, Au-Ag-Cu-Pd, and Ag-Pd-Cu-Au, while the laser-welded bars were all Ti-Al-V alloy. Bars were made from the same master cast, were torqued into place, and the total strain in the bars was measured through five strain gauges bonded to the bar between the implants. Each bar was placed and torqued 27 times to 30 Ncm per screw using three tightening sequences. Data were processed through a strain amplifier and analyzed by computer using StrainSmart software. Data were analyzed by ANOVA and Tukey's post hoc test. Significant differences were found between alloy types. Laser-welded titanium bars tended to have lower strains than corresponding cast bars, although the Au-Ag-Pd bar was not significantly different. The magnitudes of total strain were the least when first tightening the ends of the bar. The passivity of implant overdenture bars was evaluated using total strain of the bar when tightening. Selecting a high modulus of elasticity cast alloy or use of laser-welded bar design resulted in the lowest average strain magnitudes. While the effect of screw tightening sequence was minimal, tightening the distal ends first demonstrated the lowest strain, and hence the best passivity.

Influence of abutment materials on the implant-abutment joint stability in internal conical connection type implant systems.

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Jo, Jae-Young; Yang, Dong-Seok; Huh, Jung-Bo; Heo, Jae-Chan; Yun, Mi-Jung; Jeong, Chang-Mo

2014-12-01

This study evaluated the influence of abutment materials on the stability of the implant-abutment joint in internal conical connection type implant systems. Internal conical connection type implants, cement-retained abutments, and tungsten carbide-coated abutment screws were used. The abutments were fabricated with commercially pure grade 3 titanium (group T3), commercially pure grade 4 titanium (group T4), or Ti-6Al-4V (group TA) (n=5, each). In order to assess the amount of settlement after abutment fixation, a 30-Ncm tightening torque was applied, then the change in length before and after tightening the abutment screw was measured, and the preload exerted was recorded. The compressive bending strength was measured under the ISO14801 conditions. In order to determine whether there were significant changes in settlement, preload, and compressive bending strength before and after abutment fixation depending on abutment materials, one-way ANOVA and Tukey's HSD post-hoc test was performed. Group TA exhibited the smallest mean change in the combined length of the implant and abutment before and after fixation, and no difference was observed between groups T3 and T4 (P>.05). Group TA exhibited the highest preload and compressive bending strength values, followed by T4, then T3 (Pabutment material can influence the stability of the interface in internal conical connection type implant systems. The strength of the abutment material was inversely correlated with settlement, and positively correlated with compressive bending strength. Preload was inversely proportional to the frictional coefficient of the abutment material.

PIXE microbeam analysis of the metallic debris release around endosseous implants

International Nuclear Information System (INIS)

Buso, G.P.; Galassini, S.; Moschini, G.; Passi, P.; Zadro, A.; Uzunov, N.M.; Doyle, B.L.; Rossi, P.; Provencio, P.

2005-01-01

The mechanical friction that occurs during the surgical insertion of endosseous implants, both in dentistry and orthopaedics, may cause the detachment of metal debris which are dislodged into the peri-implant tissues and can lead to adverse clinical effects. This phenomenon more likely happens with coated or roughened implants that are the most widely employed. In the present study were studied dental implants screws made of commercially pure titanium and coated using titanium plasma-spray (TPS) technique. The implants were inserted in the tibia of rabbits, and removed 'en bloc' with the surrounding bone after one month. After proper processing and mounting on plastic holders, samples from bones were analysed by EDXRF setup at of National Laboratories of Legnaro, INFN, Italy, and consequently at 3 MeV proton microbeam setup at Sandia National Laboratories. Elemental maps were drawn, showing some occasional presence of metal particles in the peri-implant bone

Revival of pure titanium for dynamically loaded porous implants using additive manufacturing

International Nuclear Information System (INIS)

Wauthle, Ruben; Ahmadi, Seyed Mohammad; Amin Yavari, Saber; Mulier, Michiel; Zadpoor, Amir Abbas; Weinans, Harrie; Van Humbeeck, Jan; Kruth, Jean-Pierre; Schrooten, Jan

2015-01-01

Additive manufacturing techniques are getting more and more established as reliable methods for producing porous metal implants thanks to the almost full geometrical and mechanical control of the designed porous biomaterial. Today, Ti6Al4V ELI is still the most widely used material for porous implants, and none or little interest goes to pure titanium for use in orthopedic or load-bearing implants. Given the special mechanical behavior of cellular structures and the material properties inherent to the additive manufacturing of metals, the aim of this study is to investigate the properties of selective laser melted pure unalloyed titanium porous structures. Therefore, the static and dynamic compressive properties of pure titanium structures are determined and compared to previously reported results for identical structures made from Ti6Al4V ELI and tantalum. The results show that porous Ti6Al4V ELI still remains the strongest material for statically loaded applications, whereas pure titanium has a mechanical behavior similar to tantalum and is the material of choice for cyclically loaded porous implants. These findings are considered to be important for future implant developments since it announces a potential revival of the use of pure titanium for additively manufactured porous implants. - Highlights: • The mechanical properties of CP Ti grade 1 porous structures are studied. • The results are compared with identical structures in Ti6Al4V ELI and tantalum. • Ti6Al4V ELI structures are about two times stronger under a static compressive load. • CP Ti structures deform continuously without fracture while loaded statically. • CP Ti structures have a higher fatigue life compared to Ti6Al4V ELI structures

Revival of pure titanium for dynamically loaded porous implants using additive manufacturing

Energy Technology Data Exchange (ETDEWEB)

Wauthle, Ruben, E-mail: ruben.wauthle@3dsystems.com [KU Leuven, Department of Mechanical Engineering, Section Production Engineering, Machine Design and Automation (PMA), Celestijnenlaan 300B, 3001 Leuven (Belgium); 3D Systems - LayerWise NV, Grauwmeer 14, 3001 Leuven (Belgium); Ahmadi, Seyed Mohammad; Amin Yavari, Saber [Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628 CD, Delft (Netherlands); Mulier, Michiel [KU Leuven, Department of Orthopaedics, Weligerveld 1, 3212 Pellenberg (Belgium); Zadpoor, Amir Abbas [Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628 CD, Delft (Netherlands); Weinans, Harrie [Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628 CD, Delft (Netherlands); Department of Orthopedics & department of Rheumatology, UMC Utrecht, Heidelberglaan 100, 3584 CX, Utrecht (Netherlands); Van Humbeeck, Jan [KU Leuven, Department of Materials Engineering, Kasteelpark Arenberg 44, PB 2450, 3001 Leuven (Belgium); Kruth, Jean-Pierre [KU Leuven, Department of Mechanical Engineering, Section Production Engineering, Machine Design and Automation (PMA), Celestijnenlaan 300B, 3001 Leuven (Belgium); Schrooten, Jan [KU Leuven, Department of Materials Engineering, Kasteelpark Arenberg 44, PB 2450, 3001 Leuven (Belgium); KU Leuven, Prometheus, Division of Skeletal Tissue Engineering, PB 813, O& N1, Herestraat 49, 3000 Leuven (Belgium)

2015-09-01

Additive manufacturing techniques are getting more and more established as reliable methods for producing porous metal implants thanks to the almost full geometrical and mechanical control of the designed porous biomaterial. Today, Ti6Al4V ELI is still the most widely used material for porous implants, and none or little interest goes to pure titanium for use in orthopedic or load-bearing implants. Given the special mechanical behavior of cellular structures and the material properties inherent to the additive manufacturing of metals, the aim of this study is to investigate the properties of selective laser melted pure unalloyed titanium porous structures. Therefore, the static and dynamic compressive properties of pure titanium structures are determined and compared to previously reported results for identical structures made from Ti6Al4V ELI and tantalum. The results show that porous Ti6Al4V ELI still remains the strongest material for statically loaded applications, whereas pure titanium has a mechanical behavior similar to tantalum and is the material of choice for cyclically loaded porous implants. These findings are considered to be important for future implant developments since it announces a potential revival of the use of pure titanium for additively manufactured porous implants. - Highlights: • The mechanical properties of CP Ti grade 1 porous structures are studied. • The results are compared with identical structures in Ti6Al4V ELI and tantalum. • Ti6Al4V ELI structures are about two times stronger under a static compressive load. • CP Ti structures deform continuously without fracture while loaded statically. • CP Ti structures have a higher fatigue life compared to Ti6Al4V ELI structures.

Early Healing Events around Titanium Implant Devices with Different Surface Microtopography: A Pilot Study in an In Vivo Rabbit Model

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Ester Orsini

2012-01-01

Full Text Available In the present pilot study, the authors morphologically investigated sandblasted, acid-etched surfaces (SLA at very early experimental times. The tested devices were titanium plate-like implants with flattened wide lateral sides and jagged narrow sides. Because of these implant shape and placement site, the device gained a firm mechanical stability but the largest portion of the implant surface lacked direct contact with host bone and faced a wide peri-implant space rich in marrow tissue, intentionally created in order to study the interfacial interaction between metal surface and biological microenvironment. The insertion of titanium devices into the proximal tibia elicited a sequence of healing events. Newly formed bone proceeded through an early distance osteogenesis, common to both surfaces, and a delayed contact osteogenesis which seemed to follow different patterns at the two surfaces. In fact, SLA devices showed a more osteoconductive behavior retaining a less dense blood clot, which might be earlier and more easily replaced, and leading to a surface-conditioning layer which promotes osteogenic cell differentiation and appositional new bone deposition at the titanium surface. This model system is expected to provide a starting point for further investigations which clarify the early cellular and biomolecular events occurring at the metal surface.

Corrosion resistance of titanium ion implanted AZ91 magnesium alloy

International Nuclear Information System (INIS)

Liu Chenglong; Xin Yunchang; Tian Xiubo; Zhao, J.; Chu, Paul K.

2007-01-01

Degradable metal alloys constitute a new class of materials for load-bearing biomedical implants. Owing to their good mechanical properties and biocompatibility, magnesium alloys are promising in degradable prosthetic implants. The objective of this study is to improve the corrosion behavior of surgical AZ91 magnesium alloy by titanium ion implantation. The surface characteristics of the ion implanted layer in the magnesium alloys are examined. The authors' results disclose that an intermixed layer is produced and the surface oxidized films are mainly composed of titanium oxide with a lesser amount of magnesium oxide. X-ray photoelectron spectroscopy reveals that the oxide has three layers. The outer layer which is 10 nm thick is mainly composed of MgO and TiO 2 with some Mg(OH) 2 . The middle layer that is 50 nm thick comprises predominantly TiO 2 and MgO with minor contributions from MgAl 2 O 4 and TiO. The third layer from the surface is rich in metallic Mg, Ti, Al, and Ti 3 Al. The effects of Ti ion implantation on the corrosion resistance and electrochemical behavior of the magnesium alloys are investigated in simulated body fluids at 37±1 deg. C using electrochemical impedance spectroscopy and open circuit potential techniques. Compared to the unimplanted AZ91 alloy, titanium ion implantation significantly shifts the open circuit potential (OCP) to a more positive potential and improves the corrosion resistance at OCP. This phenomenon can be ascribed to the more compact surface oxide film, enhanced reoxidation on the implanted surface, as well as the increased β-Mg 12 Al 17 phase

Dynamic sterilization of titanium implants with ultraviolet light

International Nuclear Information System (INIS)

Singh, S.; Schaaf, N.G.

1989-01-01

All implantable devices must be sterile. However, autoclaves produce poor surface properties that jeopardize the integration process. The application of a modified ultraviolet light source has proven to enhance bioreactivity by controlling surface properties, but it lacks validation of its sterilization capabilities. Forty-eight titanium implants were contaminated with spores of the biological indicator Bacillus stearothermophilus and subjected to dynamic sterilization by ultraviolet light. Forty-seven of the implants were successfully sterilized, as indicated by not producing turbidity in a suitable growth medium. This sterilization technique only requires a 20-second exposure to achieve sterility

The influence of screw type, alloy and cylinder position on the marginal fit of implant frameworks before and after laser welding Influência do tipo de parafuso, liga e da posição do cilindro na adaptação marginal das infra-estruturas sob implantes antes e após a soldagem a laser

Directory of Open Access Journals (Sweden)

Daniela Castilio

2006-04-01

Full Text Available Misfit at the abutment-prosthetic cylinder interface can cause loss of preload, leading to loosening or fracture of gold and titanium screws. OBJECTIVES: To evaluate the influence of screw type, alloy, and cylinder position on marginal fit of implant frameworks before and after laser welding. METHODS: After Estheticone-like abutments were screwed to the implants, thirty plastic prosthetic cylinders were mounted and waxed-up to fifteen cylindrical bars. Each specimen had three interconnected prosthetic components. Five specimens were one-piece cast in titanium and five in cobalt-chromium alloy. On each specimen, tests were conducted with hexagonal titanium and slotted gold screws separately, performing a total of thirty tested screws. Measurements at the interfaces were performed using an optical microscope with 5mm accuracy. After sectioning, specimens were laser welded and new measurements were obtained. Data were submitted to a four-way ANOVA and Tukey's multiple comparisons test (alpha=0.05. RESULTS: Slotted and hexagonal screws did not present significant differences regarding to the fit of cylinders cast in titanium, either in one-piece casting framework or after laser welding. When slotted and hexagonal screws were tested on the cobalt-chromium specimens, statistically significant differences were found for the one-piece casting condition, with the slotted screws presenting better fit (24.13µm than the hexagonal screws (27.93 µm. Besides, no statistically significant differences were found after laser welding. CONCLUSIONS: 1 The use of different metal alloys do exert influence on the marginal fit, 2 The slotted and hexagonal screws play the exclusive role of fixing the prosthesis, and did not improve the fit of cylinders, and 3 cylinder position did not affect marginal fit values.A desadaptação na interface abutment-cilindro protético pode causar perda da pré-carga, levando ao afrouxamento ou fratura dos parafusos de ouro e tit

Displacement of screw-retained single crowns into implants with conical internal connections.

Science.gov (United States)

Yilmaz, Burak; Seidt, Jeremy D; McGlumphy, Edwin A; Clelland, Nancy L

2013-01-01

Internal conical implant-abutment connections without platforms may lead to axial displacement of crowns during screw tightening. This displacement may affect proximal contacts, incisal edge position, or occlusion. This study aimed to measure the displacement of screw-retained single crowns into an implant in three dimensions during screw tightening by hand or via torque driver. A stereolithic acrylic resin cast was created using computed tomography data from a patient missing the maxillary right central incisor. A 4.0- × 11-mm implant was placed in the edentulous site. Five porcelain-fused-to-metal single crowns were made using "cast-to" abutments. Crowns were tried on the stereolithic model, representing the patient, and hand tightened. The spatial relationship of crowns to the model after hand tightening was determined using three-dimensional digital image correlation (3D DIC), an optical measurement technique. The crowns were then tightened using a torque driver to 20 Ncm and the relative crown positions were again recorded. Testing was repeated three times for each crown, and displacement of the crowns was compared between the hand-tightened and torqued states. Commercial image correlation software was used to analyze the data. Mean vertical and horizontal crown displacement values were calculated after torqueing. The interproximal contacts were evaluated before and after torquing using an 8-μm aluminum foil shim. There were vertical and horizontal differences in crown positions between hand tightening and torqueing. Although these were small in magnitude, detectable displacements occurred in both apical and facial directions. After hand tightening, the 8-μm shim could be dragged without tearing. However, after torque tightening, the interproximal contacts were too tight and the 8-μm shim could not be dragged without tearing. Differences between hand tightening and torque tightening should be taken into consideration during laboratory and clinical

A Wrapping Method for Inserting Titanium Micro-Mesh Implants in the Reconstruction of Blowout Fractures

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Tae Joon Choi

2016-01-01

Full Text Available Titanium micro-mesh implants are widely used in orbital wall reconstructions because they have several advantageous characteristics. However, the rough and irregular marginal spurs of the cut edges of the titanium mesh sheet impede the efficacious and minimally traumatic insertion of the implant, because these spurs may catch or hook the orbital soft tissue, skin, or conjunctiva during the insertion procedure. In order to prevent this problem, we developed an easy method of inserting a titanium micro-mesh, in which it is wrapped with the aseptic transparent plastic film that is used to pack surgical instruments or is attached to one side of the inner suture package. Fifty-four patients underwent orbital wall reconstruction using a transconjunctival or transcutaneous approach. The wrapped implant was easily inserted without catching or injuring the orbital soft tissue, skin, or conjunctiva. In most cases, the implant was inserted in one attempt. Postoperative computed tomographic scans showed excellent placement of the titanium micro-mesh and adequate anatomic reconstruction of the orbital walls. This wrapping insertion method may be useful for making the insertion of titanium micro-mesh implants in the reconstruction of orbital wall fractures easier and less traumatic.

Multifunctions of dual Zn/Mg ion co-implanted titanium on osteogenesis, angiogenesis and bacteria inhibition for dental implants.

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Yu, Yiqiang; Jin, Guodong; Xue, Yang; Wang, Donghui; Liu, Xuanyong; Sun, Jiao

2017-02-01

In order to improve the osseointegration and long-term survival of dental implants, it is urgent to develop a multifunctional titanium surface which would simultaneously have osteogeneic, angiogeneic and antibacterial properties. In this study, a potential dental implant material-dual Zn/Mg ion co-implanted titanium (Zn/Mg-PIII) was developed via plasma immersion ion implantation (PIII). The Zn/Mg-PIII surfaces were found to promote initial adhesion and spreading of rat bone marrow mesenchymal stem cells (rBMSCs) via the upregulation of the gene expression of integrin α1 and integrin β1. More importantly, it was revealed that Zn/Mg-PIII could increase Zn 2+ and Mg 2+ concentrations in rBMSCs by promoting the influx of Zn 2+ and Mg 2+ and inhibiting the outflow of Zn 2+ , and then could enhance the transcription of Runx2 and the expression of ALP and OCN. Meanwhile, Mg 2+ ions from Zn/Mg-PIII increased Mg 2+ influx by upregulating the expression of MagT1 transporter in human umbilical vein endothelial cells (HUVECs), and then stimulated the transcription of VEGF and KDR via activation of hypoxia inducing factor (HIF)-1α, thus inducing angiogenesis. In addition to this, it was discovered that zinc in Zn/Mg-PIII had certain inhibitory effects on oral anaerobic bacteria (Pg, Fn and Sm). Finally, the Zn/Mg-PIII implants were implanted in rabbit femurs for 4 and 12weeks with Zn-PIII, Mg-PIII and pure titanium as controls. Micro-CT evaluation, sequential fluorescent labeling, histological analysis and push-out test consistently demonstrated that Zn/Mg-PIII implants exhibit superior capacities for enhancing bone formation, angiogenesis and osseointegration, while consequently increasing the bonding strength at bone-implant interfaces. All these results suggest that due to the multiple functions co-produced by zinc and magnesium, rapid osseointegration and sustained biomechanical stability are enhanced by the novel Zn/Mg-PIII implants, which have the potential

Bone reactions adjacent to titanium implants subjected to static load. A study in the dog (I)

DEFF Research Database (Denmark)

Gotfredsen, K; Berglundh, T; Lindhe, J

2001-01-01

The aim of the study was to evaluate the effect of lateral static load induced by an expansion force on the bone/implant interface and adjacent peri-implant bone. In 3 beagle dogs, the 2nd, 3rd and 4th mandibular premolars were extracted bilaterally. Twelve weeks later 8 implants of the ITI Dental...... Implant System were placed in each dog. Crowns connected in pairs were screwed on the implants 12 weeks after implant installation. The connected crowns contained an orthodontic expansion screw yielding 4 loading units in each dog. Clinical registrations, standardized radiographs and fluorochrome labeling...... were carried out during the 24-week loading period. Biopsies were harvested and processed for ground sectioning. The sections were subjected to histological examination. No evident marginal bone loss was observed at either test or control sites. The bone density and the mineralized bone-to-implant...

Peen treatment on a titanium implant: effect of roughness, osteoblast cell functions, and bonding with bone cement

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Khandaker M

2016-02-01

Full Text Available Morshed Khandaker,1,4 Shahram Riahinezhad,1 Fariha Sultana,1 Melville B Vaughan,2,4 Joshua Knight,2 Tracy L Morris3,4 1Department of Engineering & Physics, 2Department of Biology, 3Department of Mathematics and Statistics, 4Center for Interdisciplinary Biomedical Education and Research, University of Central Oklahoma, Edmond, OK, USA Abstract: Implant failure due to poor integration of the implant with the surrounding biomaterial is a common problem in various orthopedic and orthodontic surgeries. Implant fixation mostly depends upon the implant surface topography. Micron to nanosize circular-shaped groove architecture with adequate surface roughness can enhance the mechanical interlock and osseointegration of an implant with the host tissue and solve its poor fixation problem. Such groove architecture can be created on a titanium (Ti alloy implant by laser peening treatment. Laser peening produces deep, residual compressive stresses in the surfaces of metal parts, delivering increased fatigue life and damage tolerance. The scientific novelty of this study is the controlled deposition of circular-shaped rough spot groove using laser peening technique and understanding the effect of the treatment techniques for improving the implant surface properties. The hypothesis of this study was that implant surface grooves created by controlled laser peen treatment can improve the mechanical and biological responses of the implant with the adjoining biomaterial. The objective of this study was to measure how the controlled laser-peened groove architecture on Ti influences its osteoblast cell functions and bonding strength with bone cement. This study determined the surface roughness and morphology of the peen-treated Ti. In addition, this study compared the osteoblast cell functions (adhesion, proliferation, and differentiation between control and peen-treated Ti samples. Finally, this study measured the fracture strength between each kind of Ti samples

Superior biocompatibility and osteogenic efficacy of micro-arc oxidation-treated titanium implants in the canine mandible

International Nuclear Information System (INIS)

Ran Wei; Guo Bing; Shu Dalong; Tian Zhihui; Nan Kaihui; Wang Yingjun

2009-01-01

The aim of this paper is to test implantation outcomes and osteogenic efficacy of plasma micro-arc oxidation (MAO)-treated titanium implants in dogs. Thirty-six pure titanium implants (18 MAO-treated, 18 untreated) were inserted into the mandibles of nine adult beagles and allowed to heal under non-weight-bearing conditions. Implant stability and interface characteristics were evaluated at 4, 8 and 12 weeks post-implantation. Methods included scanning electron microscopy, mechanical testing, histological analysis and computer-quantified tissue morphology. Osseointegration was achieved in both groups, but occurred earlier and more extensively in the MAO group. Areas of direct bone/implant contact were approximately nine times higher in the MAO group than in the control group at 12 weeks (65.85% versus 7.37%, respectively; p < 0.01). Bone-implant shear strength in the MAO group (71.4, 147.2 and 266.3 MPa at weeks 4, 8 and 12, respectively) was higher than in the control group (4.3, 7.1, and 11.8 MPa at weeks 4, 8 and 12, respectively), at all assessments (all, p < 0.01). MAO treatment of titanium implants promotes more rapid formation of new bone, and increases bone-implant shear strength compared to untreated titanium implants.

[Effect of low dose aspirin on osseointegration around titanium implants in osteoporotic rats].

Science.gov (United States)

Yang, Q; Li, F L

2018-02-09

Objective: To investigate the effect of aspirin on osseointegration around titanium implants in ostoeporotic rats and to provide evidence for future researches and clinical application. Methods: A total of 60 female SD rats, aged 3-4 months, were divided into ovariectomy group (Ovx group, n= 48) and sham-ovariectomy group (Sham group, n= 12). The rats in Ovx group received ovariectomy and those in Sham group underwent sham-ovariectomy. Twelve weeks later, six rats in each group were randomly selected to confirm the osteoporosis models. The Ovx group was divided into 4 subgroups with 12 rats in each group, namely the osteoporosis group (OP group), and Aspirin groups (A1, A2, A3 group). Pure screw titanium implants were placed in the right tibia near metaphysis of all rats. Three days after implant surgery, aspirin groups were intragastrically administered aspirin at a dose of 2.06, 4.11, 8.21 mg·kg(-1)·d(-1) (A1, A2, A3), and OP group and Sham group were fed the same amount of normal saline. Four and 12 weeks following implantations surgery, half of the rats in each group were randomly chosen and sacrificed. Implant bone contact rate (IBCR), combined bone lamella width (CBLW) and trabercular width (TW) were observed and calculated using histomorphometric measurement. Results: Four weeks after implantations surgery, the TW and CBLW of rats in A1 group [(39.60±2.77) and (27.56±4.14) μm] and the IBCR, TW and CBLW of rats in A2 group and A3 group [A2: (47.21±4.19)%, (48.74±3.20) and (35.91±3.79) μm; A3: (47.35±6.07)%, (50.27±5.25) and (40.66±2.11) μm] were much higher than those in OP group [(33.89±7.17)%, (32.20±6.10) and (19.77±6.80) μm]( P 0.05). Twelve weeks after implantations surgery, the IBCR and CBLW of rats in A1 group [ (85.86±3.64) %, (53.12±8.68) μm], and the IBCR, TW and CBLW of rats in A2 group and A3 group [A2: (85.64±3.97)%, (69.42±6.78) and (54.19±3.12) μm; A3: (86.22±3.48)%, (75.43±3.50) and (55.79±5.60) μm] were much higher

Does surface anodisation of titanium implants change osseointegration and make their extraction from bone any easier?

OpenAIRE

Langhoff, J; Mayer, J; Faber, L; Kästner, S B; Guibert, G; Zlinszky, K; Auer, J A; von Rechenberg, B

2008-01-01

Objectives: Titanium implants have a tendency for high bone-implant bonding, and, in comparison to stainless steel implants are more difficult to remove. The current study was carried out to evaluate, i) the release strength of three selected anodized titanium surfaces with increased nanohardness and low roughness, and ii) bone-implant bonding in vivo. These modified surfaces were intended to give improved anchorage while facilitating easier removal of temporary implants. Material and methods...

Titanium-Based Biomaterials for Preventing Stress Shielding between Implant Devices and Bone

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M. Niinomi

2011-01-01

Full Text Available β-type titanium alloys with low Young's modulus are required to inhibit bone atrophy and enhance bone remodeling for implants used to substitute failed hard tissue. At the same time, these titanium alloys are required to have high static and dynamic strength. On the other hand, metallic biomaterials with variable Young's modulus are required to satisfy the needs of both patients and surgeons, namely, low and high Young's moduli, respectively. In this paper, we have discussed effective methods to improve the static and dynamic strength while maintaining low Young's modulus for β-type titanium alloys used in biomedical applications. Then, the advantage of low Young's modulus of β-type titanium alloys in biomedical applications has been discussed from the perspective of inhibiting bone atrophy and enhancing bone remodeling. Further, we have discussed the development of β-type titanium alloys with a self-adjusting Young's modulus for use in removable implants.

Osseointegration of three-dimensional designed titanium implants manufactured by selective laser melting.

Science.gov (United States)

Shaoki, Algabri; Xu, Jia-Yun; Sun, Haipeng; Chen, Xian-Shuai; Ouyang, Jianglin; Zhuang, Xiu-Mei; Deng, Fei-Long

2016-10-27

The selective laser melting (SLM) technique is a recent additive manufacturing (AM) technique. Several studies have reported success in the SLM-based production of biocompatible orthopaedic implants and three-dimensional bone defect constructs. In this study, we evaluated the surface properties and biocompatibility of an SLM titanium implant in vitro and compared them with those of a machined (MA) titanium control surface. In addition, we evaluated the osseointegration capability of the SLM implants in vivo and compared it with those of MA and Nobel-speedy (Nobel-S) implants. SLM microtopographical surface analysis revealed porous and high roughness with varied geometry compared with a smooth surface in MA Ti samples but with similar favourable wettability. Osteoblast proliferation and alkaline phosphatase activity were significantly enhanced on the SLM surface. Histological analysis of the bone-implant contact ratio revealed no significant difference among SLM, MA, and Nobel-S implants. Micro-CT assessment indicated that there was no significant difference in bone volume fraction around the implant among SLM implants and other types of surface modification implants. The removal torque value measurement of SLM implants was significantly lower that of than Nobel-S implants P manufacturing technique.

Displacement of screw-retained splinted and nonsplinted restorations into implants with conical internal connections.

Science.gov (United States)

Yilmaz, Burak; Seidt, Jeremy D; Clelland, Nancy L

2014-01-01

Variable abutment displacement could potentially affect proximal contacts, incisal edge position, or occlusion of implant-supported prostheses. This study aimed to measure and compare displacements of splinted and nonsplinted restorations into implants featuring internal conical connections as screws were tightened by hand or by torque driver. A stereolithic resin model was printed using computed tomography data from a patient missing mandibular left first and second molars. Two 5.0 × 11-mm implants were placed in the edentulous site using a surgical guide. Two sets (splinted and nonsplinted) of gold screw-retained prostheses were made indirectly to fit the implants in the stereolithic model representing the patient. The axial position of the crowns relative to a fixed location on the model was recorded following hand tightening using the three-dimensional image correlation technique and image correlation software. A pair of high-resolution digital cameras provided a synchronized view of the model during the experiment. Relative crown positions were again recorded after tightening with a torque driver to 25 Ncm. Testing was repeated randomly three times for each set of crowns. Displacement data after torque tightening were compared using a factorial analysis of variance with JMP 9.0 software (SAS) followed by a Tukey-Kramer post hoc test (α = .05). Interproximal contacts were evaluated using an 8-μm tin foil shim after tightening by hand and torque driver. Displacements for splinted and nonsplinted restorations differed only in a buccal direction. The nonsplinted crowns displaced significantly more than splinted crowns. Discernible differences were observed for the tin foil shim when dragged through proximal contacts following hand versus torque tightening. Differences between screw tightening by hand or torque driver should be taken into consideration during laboratory and clinical adjustments to prevent esthetic and functional complications.

Laser beam welding of titanium nitride coated titanium using pulse-shaping

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Milton Sergio Fernandes de Lima

2005-09-01

Full Text Available A new welding method which allows the assembly of two titanium nitride coated titanium parts is proposed. The welding procedure utilizes the possibility for pulse-shaping in order to change the energy distribution profile during the laser pulse. The pulse-shaping is composed of three elements: a a short high power pulse for partial ablation at the surface; b a long pulse for thermal penetration; and c a quenching slope for enhanced weldability. The combination of these three elements produces crack-free welds. The weld microstructure is changed in comparison to normal welding, i.e. with a rectangular pulse, as the nitrogen and the microhardness are more homogenously distributed in the weld under pulse-shaping conditions. This laser pulse dissolves the TiN layer and allows nitrogen to diffuse into the melt pool, also contributing to an enhanced weldability by providing suitable thermal conditions.

Fracture strength of zirconia implant abutments on narrow diameter implants with internal and external implant abutment connections: A study on the titanium resin base concept.

Science.gov (United States)

Sailer, Irena; Asgeirsson, Asgeir G; Thoma, Daniel S; Fehmer, Vincent; Aspelund, Thor; Özcan, Mutlu; Pjetursson, Bjarni E

2018-04-01

There is limited knowledge regarding the strength of zirconia abutments with internal and external implant abutment connections and zirconia abutments supported by a titanium resin base (Variobase, Straumann) for narrow diameter implants. To compare the fracture strength of narrow diameter abutments with different types of implant abutment connections after chewing simulation. Hundred and twenty identical customized abutments with different materials and implant abutment connections were fabricated for five groups: 1-piece zirconia abutment with internal connection (T1, Cares-abutment-Straumann BL-NC implant, Straumann Switzerland), 1-piece zirconia abutment with external hex connection (T2, Procera abutment-Branemark NP implant, Nobel Biocare, Sweden), 2-piece zirconia abutments with metallic insert for internal connection (T3, Procera abutment-Replace NP implant, Nobel Biocare), 2-piece zirconia abutment on titanium resin base (T4, LavaPlus abutment-VarioBase-Straumann BL-NC implant, 3M ESPE, Germany) and 1-piece titanium abutment with internal connection (C, Cares-abutment-Straumann BL-NC implant, Straumann, Switzerland). All implants had a narrow diameter ranging from 3.3 to 3.5 mm. Sixty un-restored abutments and 60 abutments restored with glass-ceramic crowns were tested. Mean bending moments were compared using ANOVA with p-values adjusted for multiple comparisons using Tukey's procedure. The mean bending moments were 521 ± 33 Ncm (T4), 404 ± 36 Ncm (C), 311 ± 106 Ncm (T1) 265 ± 22 Ncm (T3) and 225 ± 29 (T2) for un-restored abutments and 278 ± 84 Ncm (T4), 302 ± 170 Ncm (C), 190 ± 55 Ncm (T1) 80 ± 102 Ncm (T3) and 125 ± 57 (T2) for restored abutments. For un-restored abutments, C and T4 had similar mean bending moments, significantly higher than those of the three other groups (p internal connection had higher bending moments than zirconia abutments with external connection (T2) (p internal connected zirconia

[Susceptibility to infections and behavior of stainless steel : Comparison with titanium implants in traumatology].

Science.gov (United States)

Haubruck, Patrick; Schmidmaier, Gerhard

2017-02-01

Despite modern treatment options, implant-associated infections (IAI) remain a severe and challenging complication in the treatment of trauma patients. Almost 30 years after the introduction of implants made of titanium alloy into the treatment of trauma patients, there is still no uniform consensus regarding the clinical benefit of titanium alloy in the context of patients with IAI. We sought to determine if implants made of titanium alloy have been proven to be less susceptible regarding IAI in contrast to implants made of stainless steel. A review of the current literature on IAI in association with the utilized implant material was conducted. Relevant articles from the years 1995 to 2016 were searched in the PubMed database. A total of 183 articles were identified and all abstracts were reviewed for relevance. A total of 14 articles met the inclusion criteria and were stratified according to the level of evidence and furthermore evaluated regarding the influence of the implant material on IAI. Considerable debate remains concerning the influence of the implant material on the susceptibility to IAI; however, the available literature shows that despite slight tendencies, there is no proof of titanium alloy being favorable in the susceptibility to IAI. Furthermore, the literature shows that the design of plates for osteosynthesis might influence IAI. In particular, plates that cause less soft tissue damage and preserve perfusion of the periosteum proved to be beneficial regarding IAI.

A comparative study of zirconium and titanium implants in rat: osseointegration and bone material quality.

Science.gov (United States)

Hoerth, Rebecca M; Katunar, María R; Gomez Sanchez, Andrea; Orellano, Juan C; Ceré, Silvia M; Wagermaier, Wolfgang; Ballarre, Josefina

2014-02-01

Permanent metal implants are widely used in human medical treatments and orthopedics, for example as hip joint replacements. They are commonly made of titanium alloys and beyond the optimization of this established material, it is also essential to explore alternative implant materials in view of improved osseointegration. The aim of our study was to characterize the implant performance of zirconium in comparison to titanium implants. Zirconium implants have been characterized in a previous study concerning material properties and surface characteristics in vitro, such as oxide layer thickness and surface roughness. In the present study, we compare bone material quality around zirconium and titanium implants in terms of osseointegration and therefore characterized bone material properties in a rat model using a multi-method approach. We used light and electron microscopy, micro Raman spectroscopy, micro X-ray fluorescence and X-ray scattering techniques to investigate the osseointegration in terms of compositional and structural properties of the newly formed bone. Regarding the mineralization level, the mineral composition, and the alignment and order of the mineral particles, our results show that the maturity of the newly formed bone after 8 weeks of implantation is already very high. In conclusion, the bone material quality obtained for zirconium implants is at least as good as for titanium. It seems that the zirconium implants can be a good candidate for using as permanent metal prosthesis for orthopedic treatments.

Comparison of stainless steel and titanium alloy orthodontic miniscrew implants: a mechanical and histologic analysis.

Science.gov (United States)

Brown, Ryan N; Sexton, Brent E; Gabriel Chu, Tien-Min; Katona, Thomas R; Stewart, Kelton T; Kyung, Hee-Moon; Liu, Sean Shih-Yao

2014-04-01

The detailed mechanical and histologic properties of stainless steel miniscrew implants used for temporary orthodontic anchorage have not been assessed. Thus, the purpose of this study was to compare them with identically sized titanium alloy miniscrew implants. Forty-eight stainless steel and 48 titanium alloy miniscrew implants were inserted into the tibias of 12 rabbits. Insertion torque and primary stability were recorded. One hundred grams of tensile force was applied between half of the implants in each group, resulting in 4 subgroups of 24 specimens each. Fluorochrome labeling was administered at weeks 4 and 5. When the rabbits were euthanized at 6 weeks, stability and removal torque were measured in half (ie, 12 specimens) of each of the 4 subgroups. Microdamage burden and bone-to-implant contact ratio were quantified in the other 12 specimens in each subgroup. Mixed model analysis of variance was used for statistical analysis. All implants were stable at insertion and after 6 weeks. The only significant difference was the higher (9%) insertion torque for stainless steel. No significant differences were found between stainless steel and titanium alloy miniscrew implants in microdamage burden and bone-to-implant contact regardless of loading status. Stainless steel and titanium alloy miniscrew implants provide the same mechanical stability and similar histologic responses, suggesting that both are suitable for immediate orthodontic clinical loads. Copyright © 2014 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

Micro-morphologic changes around biophysically-stimulated titanium implants in ovariectomized rats

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Chang Ting-Ling

2007-07-01

Full Text Available Abstract Background Osteoporosis may present a risk factor in achievement of osseointegration because of its impact on bone remodeling properties of skeletal phsiology. The purpose of this study was to evaluate micro-morphological changes in bone around titanium implants exposed to mechanical and electrical-energy in osteoporotic rats. Methods Fifteen 12-week old sprague-dowley rats were ovariectomized to develop osteoporosis. After 8 weeks of healing period, two titanium implants were bilaterally placed in the proximal metaphyses of tibia. The animals were randomly divided into a control group and biophysically-stimulated two test groups with five animals in each group. In the first test group, a pulsed electromagnetic field (PEMF stimulation was administrated at a 0.2 mT 4 h/day, whereas the second group received low-magnitude high-frequency mechanical vibration (MECHVIB at 50 Hz 14 min/day. Following completion of two week treatment period, all animals were sacrificed. Bone sites including implants were sectioned, removed en bloc and analyzed using a microCT unit. Relative bone volume and bone micro-structural parameters were evaluated for 144 μm wide peri-implant volume of interest (VOI. Results Mean relative bone volume in the peri-implant VOI around implants PEMF and MECHVIB was significantly higher than of those in control (P P > .05 while the difference in trabecular-number among test and control groups was significant in all VOIs (P Conclusion Biophysical stimulation remarkably enhances bone volume around titanium implants placed in osteoporotic rats. Low-magnitude high-frequency MECHVIB is more effective than PEMF on bone healing in terms of relative bone volume.

Development of titanium alloys and surface treatments to increase the implants lifetime

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Joan Lario-Femenía

2016-12-01

Full Text Available The population aging together with increase of life expectancy forces the development of new prosthesis which may present a higher useful life. The clinical success of implants is based on the osseointegration achievement. Therefore, metal implants must have a mechanical compatibility with the substituted bone, which is achieved through a combination of low elastic modulus, high flexural and fatigue strength. The improvement, in the short and long term, of the osseointegration depends on several factors, where the macroscopic design and dimensional, material and implant surface topography are of great importance. This article is focused on summarizing the advantages that present the titanium and its alloys to be used as biomaterials, and the development that they have suffered in recent decades to improve their biocompatibility. Consequently, the implants evolution has been recapitulated and summarized through three generations. In the recent years the interest on the surface treatments for metallic prostheses has been increased, the main objective is achieve a lasting integration between implant and bone tissue, in the shortest time possible. On this article various surface treatments currently used to modify the surface roughness or to obtain coatings are described it; it is worthy to mention the electrochemical oxidation with post-heat treated to modify the titanium oxide crystalline structure. After the literature review conducted for prepare this article, the ? titanium alloys, with a nanotubes surface of obtained by electrochemical oxidation and a subsequent step of heat treatment to obtain a crystalline structure are the future option to improve long term biocompatibility of titanium prostheses.

How to Choose between the Implant Materials Steel and Titanium in Orthopedic Trauma Surgery: Part 2 - Biological Aspects.

Science.gov (United States)

Perren, S M; Regazzoni, P; Fernandez, A A

2017-01-01

BIOLOGICAL ASPECTS OF STEEL AND TITANIUM AS IMPLANT MATERIAL IN ORTHOPEDIC TRAUMA SURGERY The following case from the ICUC database, where a titanium plate was implanted into a flourishing infection, represents the clinical experience leading to preferring titanium over steel. (Fig. 1) (6). Current opinions regarding biological aspects of implant function. The "street" opinions regarding the biological aspects of the use of steel versus titanium as a surgical trauma implant material differ widely. Statements of opinion leaders range from "I do not see any difference in the biological behavior between steel and titanium in clinical application" to "I successfully use titanium implants in infected areas in a situation where steel would act as foreign body "sustaining" infection." Furthermore, some comments imply that clinical proof for the superiority of titanium in human application is lacking. The following tries to clarify the issues addressing the different aspects more through a practical clinical approach than a purely scientific one, this includes simplifications. Today's overall biocompatibility of implant materials is acceptable but: As the vast majority of secondary surgeries are elective procedures this allows the selection of implant materials with optimal infection resistance. The different biological reactions of stainless steel and titanium are important for this segment of clinical pathologies. Biological tole - rance (18) depends on the toxicity and on the amount of soluble implant material released. Release, diffusion and washout through blood circulation determine the local concentration of the corrosion products. Alloying components of steel, especially nickel and chromium, are less than optimal in respect to tissue tolerance and allergenicity. Titanium as a pure metal provides excellent biological tolerance (3, 4, 16). Better strength was obtained by titanium alloys like TiAl6V4. The latter found limited application as surgical implants. It

Torque Analysis of a Triple Acid-Etched Titanium Implant Surface

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Ana Emília Farias Pontes

2015-01-01

Full Text Available The present study aimed to evaluate the removal torque of titanium implants treated with triple acid etching. Twenty-one rats were used in this study. For all animals, the tibia was prepared with a 2 mm drill, and a titanium implant (2 × 4 mm was inserted after treatment using the subtraction method of triple acid etching. The flaps were sutured. Seven animals were killed 14, 28, and 63 days after implant installation, and the load necessary for removing the implant from the bone was evaluated by using a torque meter. The torque values were as follows: 3.3 ± 1.7 Ncm (14 days, 2.2 ± 1.3 Ncm (28 days, and 6.7 ± 1.4 Ncm (63 days. The torque value at the final healing period (63 days was statistically significantly different from that at other time points tested (ANOVA, p=0.0002. This preliminary study revealed that treatment with triple acid etching can create a promising and efficient surface for the process of osseointegration.

Characterization and evaluation of femtosecond laser-induced sub-micron periodic structures generated on titanium to improve osseointegration of implants

Science.gov (United States)

Lee, Bryan E. J.; Exir, Hourieh; Weck, Arnaud; Grandfield, Kathryn

2018-05-01

Reproducible and controllable methods of modifying titanium surfaces for dental and orthopaedic applications are of interest to prevent poor implant outcomes by improving osseointegration. This study made use of a femtosecond laser to generate laser-induced periodic surface structures with periodicities of 300, 620 and 760 nm on titanium substrates. The reproducible rippled patterns showed consistent submicron scale roughness and relatively hydrophobic surfaces as measured by atomic force microscopy and contact angle, respectively. Transmission electron microscopy and Auger electron spectroscopy identified a thicker oxide layer on ablated surfaces compared to controls. In vitro testing was conducted using osteosarcoma Saos-2 cells. Cell metabolism on the laser-ablated surfaces was comparable to controls and alkaline phosphatase activity was notably increased at late time points for the 620 and 760 nm surfaces compared to controls. Cells showed a more elongated shape on laser-ablated surfaces compared to controls and showed perpendicular alignment to the periodic structures. This work has demonstrated the feasibility of generating submicron features on an implant material with the ability to influence cell response and improve implant outcomes.

Bone compaction enhances fixation of weightbearing titanium implants

DEFF Research Database (Denmark)

Kold, Søren; Rahbek, Ole; Vestermark, Marianne

2005-01-01

are weightbearing, the effects of compaction on weightbearing implants were examined. The hypothesis was that compaction would increase implant fixation compared with conventional drilling. Porous-coated titanium implants were inserted bilaterally into the weightbearing portion of the femoral condyles of dogs....... In each dog, one knee had the implant cavity prepared with drilling, and the other knee was prepared with compaction. Eight dogs were euthanized after 2 weeks, and eight dogs were euthanized after 4 weeks. Femoral condyles from an additional eight dogs represented Time 0. Compacted specimens had higher...... bone-implant contact and periimplant bone density at 0 and 2 weeks, but not at 4 weeks. A biphasic response of compaction was found with a pushout test, as compaction increased ultimate shear strength and energy absorption at 0 and 4 weeks, but not at 2 weeks. This biphasic response indicates...

Ion enhanced deposition by dual titanium and acetylene plasma immersion ion implantation

Science.gov (United States)

Zeng, Z. M.; Tian, X. B.; Chu, P. K.

2003-01-01

Plasma immersion ion implantation and deposition (PIII-D) offers a non-line-of-sight fabrication method for various types of thin films on steels to improve the surface properties. In this work, titanium films were first deposited on 9Cr18 (AISI440) stainless bearing steel by metal plasma immersion ion implantation and deposition (MePIII-D) using a titanium vacuum arc plasma source. Afterwards, carbon implantation and carbon film deposition were performed by acetylene (C2H2) plasma immersion ion implantation. Multiple-layered structures with superior properties were produced by conducting Ti MePIII-D + C2H2 PIII successively. The composition and structure of the films were investigated employing Auger electron spectroscopy and Raman spectroscopy. It is shown that the mixing for Ti and C atoms is much better when the target bias is higher during Ti MePIII-D. A top diamond-like carbon layer and a titanium oxycarbide layer are formed on the 9Cr18 steel surface. The wear test results indicate that this dual PIII-D method can significantly enhance the wear properties and decrease the surface friction coefficient of 9Cr18 steel.

Ion enhanced deposition by dual titanium and acetylene plasma immersion ion implantation

International Nuclear Information System (INIS)

Zeng, Z.M.; Tian, X.B.; Chu, P.K.

2003-01-01

Plasma immersion ion implantation and deposition (PIII-D) offers a non-line-of-sight fabrication method for various types of thin films on steels to improve the surface properties. In this work, titanium films were first deposited on 9Cr18 (AISI440) stainless bearing steel by metal plasma immersion ion implantation and deposition (MePIII-D) using a titanium vacuum arc plasma source. Afterwards, carbon implantation and carbon film deposition were performed by acetylene (C 2 H 2 ) plasma immersion ion implantation. Multiple-layered structures with superior properties were produced by conducting Ti MePIII-D + C 2 H 2 PIII successively. The composition and structure of the films were investigated employing Auger electron spectroscopy and Raman spectroscopy. It is shown that the mixing for Ti and C atoms is much better when the target bias is higher during Ti MePIII-D. A top diamond-like carbon layer and a titanium oxycarbide layer are formed on the 9Cr18 steel surface. The wear test results indicate that this dual PIII-D method can significantly enhance the wear properties and decrease the surface friction coefficient of 9Cr18 steel

Antimicrobial and Osseointegration Properties of Nanostructured Titanium Orthopaedic Implants

OpenAIRE

Jäger, Marcus; Jennissen, Herbert P.; Dittrich, Florian; Fischer, Alfons; Köhling, Hedda Luise

2017-01-01

The surface design of titanium implants influences not only the local biological reactions but also affects at least the clinical result in orthopaedic application. During the last decades, strong efforts have been made to improve osteointegration and prevent bacterial adhesion to these surfaces. Following the rule of “smaller, faster, cheaper”, nanotechnology has encountered clinical application. It is evident that the hierarchical implant surface micro- and nanotopography orchestrate the bi...

Titanium Nitride and Nitrogen Ion Implanted Coated Dental Materials

Directory of Open Access Journals (Sweden)

David W. Berzins

2012-07-01

Full Text Available Titanium nitride and/or nitrogen ion implanted coated dental materials have been investigated since the mid-1980s and considered in various applications in dentistry such as implants, abutments, orthodontic wires, endodontic files, periodontal/oral hygiene instruments, and casting alloys for fixed restorations. Multiple methodologies have been employed to create the coatings, but detailed structural analysis of the coatings is generally lacking in the dental literature. Depending on application, the purpose of the coating is to provide increased surface hardness, abrasion/wear resistance, esthetics, and corrosion resistance, lower friction, as well as greater beneficial interaction with adjacent biological and material substrates. While many studies have reported on the achievement of these properties, a consensus is not always clear. Additionally, few studies have been conducted to assess the efficacy of the coatings in a clinical setting. Overall, titanium nitride and/or nitrogen ion implanted coated dental materials potentially offer advantages over uncoated counterparts, but more investigation is needed to document the structure of the coatings and their clinical effectiveness.

Laser bioengineering of glass-titanium implants surface

Science.gov (United States)

Lusquiños, F.; Arias-González, F.; Penide, J.; del Val, J.; Comesaña, R.; Quintero, F.; Riveiro, A.; Boutinguiza, M.; Pascual, M. J.; Durán, A.; Pou, J.

2013-11-01

Osseointegration is the mean challenge when surgical treatments fight against load-bearing bone diseases. Absolute bone replacement by a synthetic implant has to be completed not only from the mechanics point of view, but also from a biological approach. Suitable strength, resilience and stress distribution of titanium alloy implants are spoiled by the lack of optimal biological characteristics. The inert quality of extra low interstitial titanium alloy, which make it the most attractive metallic alloy for biomedical applications, oppose to an ideal surface with bone cell affinity, and capable to stimulate bone attachment bone growth. Diverse laser treatments have been proven as effective tools to modify surface properties, such as wettability in contact to physiological fluids, or osteoblast guided and slightly enhanced attachment. The laser surface cladding can go beyond by providing titanium alloy surfaces with osteoconduction and osteoinduction properties. In this research work, the laser radiation is used to produce bioactive glass coatings on Ti6Al4V alloy substrates. Specific silicate bioactive glass compositions has been investigated to achieve suitable surface tension and viscosity temperature behavior during processing, and to provide with the required release of bone growth gene up regulation agents in the course of resorption mediated by physiological fluids. The produced coatings and interfaces, the surface osteoconduction properties, and the chemical species release in simulated physiological fluid were characterized by scanning electron microscopy (SEM), hot stage microscopy (HSM), X-ray diffraction (XRD), X ray fluorescence (XRF), and Fourier transform infrared spectroscopy (FTIR).

Stability of biodegradable metal (Mg-Ca-Zn alloy) screws compared with absorbable polymer and titanium screws for sagittal split ramus osteotomy of the mandible using the finite element analysis model.

Science.gov (United States)

Lee, Jee-Ho; Han, Hyung-Seop; Kim, Yu-Chan; Lee, Jin-Yong; Lee, Bu-Kyu

2017-10-01

Mg-Ca-Zn alloy has been suggested for the application of fixation materials during maxillofacial surgery. We investigated the stability of Mg-Ca-Zn alloy for clinical application during orthognathic surgery. The finite element model for the fixation of sagittal split ramus osteotomy was constructed. In the bicortical screw fixation of the mandible setback condition, the stress distributions of Mg-Ca-Za alloy, polylactic acid polymer, and titanium were evaluated using the virtual model with occlusal loading of 132 N. The deformations of the three different materials of fixation screw were observed according to masticatory force ranging from 132 to 1,000 N. When comparing the stress distribution placed on cortical bone between the polymer and magnesium alloy groups, the magnesium alloy screws could bear more stress, thereby decreasing the stress, which might be distributed to other biologic components, such as the condyle and cortical ramus of the mandible. Deformations of the screws according to functional load were minimal, and the deformation remained stability of sagittal split ramus osteotomy setback surgery. Copyright © 2017. Published by Elsevier Ltd.

Application of micro beam PIXE to detection of titanium ion release from dental and orthopaedic implants

International Nuclear Information System (INIS)

Ektessabi, A.M.; Otsuka, T.; Tsuboi, Y.; Yokoyama, K.; Albrektsson, T.; Sennerby, L.; Johansson, C.

1994-01-01

In the past two decades the utilization of dental and orthopaedic implants in reconstructive surgery has been spread widely. Most of these implants are inserted in the corrosive environment of the human body for long periods of time. The level of dissolution, release, and transport of metal ions as a result of corrosion of these materials are not fully known at present. We report the results of application of micro ion beam PIXE spectroscopy to detect release of titanium from titanium and titanium alloy implants inserted in the tibiae of rabbits for three months. It was found that titanium ions could be detected in the surrounding tissues, with high precision, as a gradient from the implant surface and in higher amounts in the bone tissue as compared with the soft tissues. It is concluded that application of micro ion beam PIXE spectroscopy for detection of metal ion release, and distribution of the released material around the implants with high special resolution and accuracy may be used to further investigate the mechanism of metal release, and the relation between surface micromorphology and corrosion resistance of the implant materials. (author)

Cell Attachment Following Instrumentation with Titanium and Plastic Instruments, Diode Laser, and Titanium Brush on Titanium, Titanium-Zirconium, and Zirconia Surfaces.

Science.gov (United States)

Lang, Melissa S; Cerutis, D Roselyn; Miyamoto, Takanari; Nunn, Martha E

2016-01-01

The aim of this study was to evaluate the surface characteristics and gingival fibroblast adhesion of disks composed of implant and abutment materials following brief and repeated instrumentation with instruments commonly used in procedures for implant maintenance, stage-two implant surgery, and periimplantitis treatment. One hundred twenty disks (40 titanium, 40 titaniumzirconium, 40 zirconia) were grouped into treatment categories of instrumentation by plastic curette, titanium curette, diode microlaser, rotary titanium brush, and no treatment. Twenty strokes were applied to half of the disks in the plastic and titanium curette treatment categories, while half of the disks received 100 strokes each to simulate implant maintenance occurring on a repetitive basis. Following analysis of the disks by optical laser profilometry, disks were cultured with human gingival fibroblasts. Cell counts were conducted from scanning electron microscopy (SEM) images. Differences in surface roughness across all instruments tested for zirconia disks were negligible, while both titanium disks and titaniumzirconium disks showed large differences in surface roughness across the spectrum of instruments tested. The rotary titanium brush and the titanium curette yielded the greatest overall mean surface roughness, while the plastic curette yielded the lowest mean surface roughness. The greatest mean cell counts for each disk type were as follows: titanium disks with plastic curettes, titanium-zirconium disks with titanium curettes, and zirconia disks with the diode microlaser. Repeated instrumentation did not result in cumulative changes in surface roughness of implant materials made of titanium, titanium-zirconium, or zirconia. Instrumentation with plastic implant curettes on titanium and zirconia surfaces appeared to be more favorable than titanium implant curettes in terms of gingival fibroblast attachment on these surfaces.

Zirconia dental implants: where are we now, and where are we heading?

Science.gov (United States)

Cionca, Norbert; Hashim, Dena; Mombelli, Andrea

2017-02-01

Despite decades of titanium as the gold standard in oral implantology, the search for alternatives has been growing. High esthetic standards and increasing incidence of titanium allergies, along with a rising demand for metal-free reconstructions, have led to the proposal of ceramics as potential surrogates. Following numerous experimental studies, zirconium dioxide (zirconia) has earned its place as a potential substitute for titanium in implantology. Yet, despite zirconia's excellent biocompatibility and tissue integration, low affinity to plaque and favorable biomechanical properties, early failures were significantly higher for zirconia implants than for titanium implants. Technical failure as a result of fracture of the material is also a major concern. So far, zirconia implants have been mainly manufactured as one-piece implant systems because of the material's limitations. Nevertheless, various two-piece systems have been progressively emerging with promising results. Screw-retained abutments are desirable but present a major technical challenge. Innovation and technical advances will undoubtedly lead to further improvement in the reliability and strength of zirconia implants, allowing for novel designs, connections and reconstructions. Additional clinical studies are required to identify all relevant technical and biological factors affecting implant success and patients' satisfaction. However, the evidence for a final verdict is, at present, still incomplete. © 2016 The Authors. Periodontology 2000 published by John Wiley & Sons Ltd.

Demineralized bone matrix and human cancellous bone enhance fixation of titanium implants

DEFF Research Database (Denmark)

Babiker, Hassan; Ding, Ming; Overgaard, Søren

Best Poster 5Demineralized bone matrix and human cancellous bone enhance fixation of titanium implants AuthorsBabiker , H.; Ding M.; Overgaard S.InstitutionOrthopaedic Research Laboratory, Department of Orthopaedic Surgery, Odense University Hospital, Clinical Institute, University of Southern...... from human tissue were included (IsoTis OrthoBiologics, Inc. USA). Both materials are commercially available. Titanium alloy implants (Biomet Inc.) of 10 mm in length and 10 mm in diameter were inserted bilaterally into the femoral condyles of 8 skeletally mature sheep. Thus four implants...... with a concentric gap of 2 mm were implanted in each sheep. The gap was filled with: DBM; DBM/CB with ratio of 1/3; DBM/allograft with ratio of 1/3; or allograft (Gold standard), respectively. Standardised surgical procedure was used1. At sacrifice, 6 weeks after surgery, both distal femurs were harvested...

Adding functionality with additive manufacturing: Fabrication of titanium-based antibiotic eluting implants

Energy Technology Data Exchange (ETDEWEB)

Cox, Sophie C. [School of Chemical Engineering, University of Birmingham, Edgbaston B15 2TT (United Kingdom); Jamshidi, Parastoo [School of Materials and Metallurgy, University of Birmingham, Edgbaston B15 2TT (United Kingdom); Eisenstein, Neil M. [School of Chemical Engineering, University of Birmingham, Edgbaston B15 2TT (United Kingdom); Royal Centre for Defence Medicine, Birmingham Research Park, Vincent Drive, Edgbaston B15 2SQ (United Kingdom); Webber, Mark A. [School of Biosciences, University of Birmingham, Edgbaston B15 2TT (United Kingdom); Hassanin, Hany [School of Materials and Metallurgy, University of Birmingham, Edgbaston B15 2TT (United Kingdom); School of Mechanical and Automotive Engineering, Kingston University, London SW15 3DW (United Kingdom); Attallah, Moataz M. [School of Materials and Metallurgy, University of Birmingham, Edgbaston B15 2TT (United Kingdom); Shepherd, Duncan E.T. [Department of Mechanical Engineering, School of Engineering, University of Birmingham, Edgbaston B15 2TT (United Kingdom); Addison, Owen [School of Dentistry, University of Birmingham, Edgbaston B15 2TT (United Kingdom); Grover, Liam M. [School of Chemical Engineering, University of Birmingham, Edgbaston B15 2TT (United Kingdom)

2016-07-01

Additive manufacturing technologies have been utilised in healthcare to create patient-specific implants. This study demonstrates the potential to add new implant functionality by further exploiting the design flexibility of these technologies. Selective laser melting was used to manufacture titanium-based (Ti-6Al-4V) implants containing a reservoir. Pore channels, connecting the implant surface to the reservoir, were incorporated to facilitate antibiotic delivery. An injectable brushite, calcium phosphate cement, was formulated as a carrier vehicle for gentamicin. Incorporation of the antibiotic significantly (p = 0.01) improved the compressive strength (5.8 ± 0.7 MPa) of the cement compared to non-antibiotic samples. The controlled release of gentamicin sulphate from the calcium phosphate cement injected into the implant reservoir was demonstrated in short term elution studies using ultraviolet-visible spectroscopy. Orientation of the implant pore channels were shown, using micro-computed tomography, to impact design reproducibility and the back-pressure generated during cement injection which ultimately altered porosity. The amount of antibiotic released from all implant designs over a 6 hour period (< 28% of the total amount) were found to exceed the minimum inhibitory concentrations of Staphylococcus aureus (16 μg/mL) and Staphylococcus epidermidis (1 μg/mL); two bacterial species commonly associated with periprosthetic infections. Antibacterial efficacy was confirmed against both bacterial cultures using an agar diffusion assay. Interestingly, pore channel orientation was shown to influence the directionality of inhibition zones. Promisingly, this work demonstrates the potential to additively manufacture a titanium-based antibiotic eluting implant, which is an attractive alternative to current treatment strategies of periprosthetic infections. - Highlights: • Titanium implants were additively manufactured with surface connected reservoirs. • Implants

Adding functionality with additive manufacturing: Fabrication of titanium-based antibiotic eluting implants

International Nuclear Information System (INIS)

Cox, Sophie C.; Jamshidi, Parastoo; Eisenstein, Neil M.; Webber, Mark A.; Hassanin, Hany; Attallah, Moataz M.; Shepherd, Duncan E.T.; Addison, Owen; Grover, Liam M.

2016-01-01

Additive manufacturing technologies have been utilised in healthcare to create patient-specific implants. This study demonstrates the potential to add new implant functionality by further exploiting the design flexibility of these technologies. Selective laser melting was used to manufacture titanium-based (Ti-6Al-4V) implants containing a reservoir. Pore channels, connecting the implant surface to the reservoir, were incorporated to facilitate antibiotic delivery. An injectable brushite, calcium phosphate cement, was formulated as a carrier vehicle for gentamicin. Incorporation of the antibiotic significantly (p = 0.01) improved the compressive strength (5.8 ± 0.7 MPa) of the cement compared to non-antibiotic samples. The controlled release of gentamicin sulphate from the calcium phosphate cement injected into the implant reservoir was demonstrated in short term elution studies using ultraviolet-visible spectroscopy. Orientation of the implant pore channels were shown, using micro-computed tomography, to impact design reproducibility and the back-pressure generated during cement injection which ultimately altered porosity. The amount of antibiotic released from all implant designs over a 6 hour period (< 28% of the total amount) were found to exceed the minimum inhibitory concentrations of Staphylococcus aureus (16 μg/mL) and Staphylococcus epidermidis (1 μg/mL); two bacterial species commonly associated with periprosthetic infections. Antibacterial efficacy was confirmed against both bacterial cultures using an agar diffusion assay. Interestingly, pore channel orientation was shown to influence the directionality of inhibition zones. Promisingly, this work demonstrates the potential to additively manufacture a titanium-based antibiotic eluting implant, which is an attractive alternative to current treatment strategies of periprosthetic infections. - Highlights: • Titanium implants were additively manufactured with surface connected reservoirs. • Implants

Effects of different titanium zirconium implant surfaces on initial supragingival plaque formation.

Science.gov (United States)

John, Gordon; Becker, Jürgen; Schwarz, Frank

2017-07-01

The aim of the current study was the evaluation of biofilm development on different implant surfaces. Initial biofilm formation was investigated on five different implant surfaces, machined titanium (MTi), modified machined acid-etched titanium (modMATi), machined titanium zirconium (MTiZr), modified machined and acid-etched titanium zirconium (modMATiZr) and sandblasted large grid and acid-etched titanium zirconium surface (SLATiZr) for 24 and 48 h. Biocompatibility was tested after tooth brushing of the samples via cell viability testing with human gingival fibroblasts. After 24 h of biofilm collection, mean plaque surface was detected in the following descending order: After 24 h: MTiZr > MTi > SLATiZr > modMATiZr > modMATi. Both M surfaces showed significant higher biofilm formation than the other groups. After 48 h: MTiZr > MTi > SLATiZr > modMATiZr > modMATi. After tooth brushing: SLATiZr > modMATi > modMATiZr > MTi > MTiZr. All native samples depicted significant higher cell viability than their corresponding surfaces after biofilm removal procedure. The TiZr groups especially the modMATiZr group showed slower and less biofilm formation. In combination with the good biocompatibility, both modMA surfaces seem to be interesting candidates for surfaces in transgingival implant design. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Gentamicin coating of plasma chemical oxidized titanium alloy prevents implant-related osteomyelitis in rats.

Science.gov (United States)

Diefenbeck, M; Schrader, C; Gras, F; Mückley, T; Schmidt, J; Zankovych, S; Bossert, J; Jandt, K D; Völpel, A; Sigusch, B W; Schubert, H; Bischoff, S; Pfister, W; Edel, B; Faucon, M; Finger, U

2016-09-01

Implant related infection is one of the most feared and devastating complication associated with the use of orthopaedic implant devices. Development of anti-infective surfaces is the main strategy to prevent implant contamination, biofilm formation and implant related osteomyelitis. A second concern in orthopaedics is insufficient osseointegration of uncemented implant devices. Recently, we reported on a macroporous titanium-oxide surface (bioactive TiOB) which increases osseointegration and implant fixation. To combine enhanced osseointegration and antibacterial function, the TiOB surfaces were, in addition, modified with a gentamicin coating. A rat osteomyelitis model with bilateral placement of titanium alloy implants was employed to analyse the prophylactic effect of gentamicin-sodiumdodecylsulfate (SDS) and gentamicin-tannic acid coatings in vivo. 20 rats were randomly assigned to four groups: (A) titanium alloy; PBS inoculum (negative control), (B) titanium alloy, Staphylococcus aureus inoculum (positive control), (C) bioactive TiOB with gentamicin-SDS and (D) bioactive TiOB plus gentamicin-tannic acid coating. Contamination of implants, bacterial load of bone powder and radiographic as well as histological signs of implant-related osteomyelitis were evaluated after four weeks. Gentamicin-SDS coating prevented implant contamination in 10 of 10 tibiae and gentamicin-tannic acid coating in 9 of 10 tibiae (infection prophylaxis rate 100% and 90% of cases, respectively). In Group (D) one implant showed colonisation of bacteria (swab of entry point and roll-out test positive for S. aureus). The interobserver reliability showed no difference in the histologic and radiographic osteomyelitis scores. In both gentamicin coated groups, a significant reduction of the histological osteomyelitis score (geometric mean values: C = 0.111 ± 0.023; D = 0.056 ± 0.006) compared to the positive control group (B: 0.244 ± 0.015; p < 0.05) was observed. The

Measurement of Tip Apex Distance and Migration of Lag Screws and Novel Blade Screw Used for the Fixation of Intertrochanteric Fractures.

Directory of Open Access Journals (Sweden)

Jesse Chieh-Szu Yang

Full Text Available Fixation with a dynamic hip screw (DHS is one of the most common methods for stabilizing intertrochanteric fractures, except for unstable and reverse oblique fracture types. However, failure is often observed in osteoporotic patients whereby the lag screw effectively 'cuts out' through the weak bone. Novel anti-migration blades have been developed to be used in combination with a lag screw ('Blade Screw' to improve the fixation strength in osteoporotic intertrochanteric fractures. An in-vitro biomechanical study and a retrospective clinical study were performed to evaluate lag screw migration when using the novel Blade Screw and a traditional threaded DHS. The biomechanical study showed both the Blade Screw and DHS displayed excessive migration (≥10 mm before reaching 20,000 loading cycles in mild osteoporotic bone, but overall migration of the Blade Screw was significantly less (p ≤ 0.03. Among the patients implanted with a Blade Screw in the clinical study, there was no significant variation in screw migration at 3-months follow-up (P = 0.12. However, the patient's implanted with a DHS did display significantly greater migration (P<0.001 than those implanted with the Blade Screw. In conclusion, the Blade Screw stabilizes the bone fragments during dynamic loading so as to provide significantly greater resistance to screw migration in patients with mild osteoporosis.

Magnesium Alloys as a Biomaterial for Degradable Craniofacial Screws

Science.gov (United States)

Henderson, Sarah E.; Verdelis, Konstantinos; Maiti, Spandan; Pal, Siladitya; Chung, William L.; Chou, Da-Tren; Kumta, Prashant N.; Almarza, Alejandro J.

2014-01-01

Recently, magnesium (Mg) alloys have received significant attention as a potential biomaterial for degradable implants, and this study was directed at evaluating the suitability of Mg for craniofacial bone screws. The objective was to implant screws fabricated from commercially available Mg-alloys (pure Mg and AZ31) in-vivo in a rabbit mandible. First, Mg-alloy screws were compared to stainless steel screws in an in-vitro pull-out test and determined to have a similar holding strength (~40N). A finite element model of the screw was created using the pull-out test data, and the model can be used for future Mg-alloy screw design. Then, Mg-alloy screws were implanted for 4, 8, and 12 weeks, with two controls of an osteotomy site (hole) with no implant and a stainless steel screw implanted for 12 weeks. MicroCT (computed tomography) was used to assess bone remodeling and Mg-alloy degradation, both visually and qualitatively through volume fraction measurements for all time points. Histologic analysis was also completed for the Mg-alloys at 12 weeks. The results showed that craniofacial bone remodeling occurred around both Mg-alloy screw types. Pure Mg had a different degradation profile than AZ31, however bone growth occurred around both screw types. The degradation rate of both Mg-alloy screw types in the bone marrow space and the muscle were faster than in the cortical bone space at 12 weeks. Furthermore, it was shown that by alloying Mg, the degradation profile could be changed. These results indicate the promise of using Mg-alloys for craniofacial applications. PMID:24384125

Carbon dioxide ion implantation in Titanium Nitride (Ti N)

International Nuclear Information System (INIS)

Torabi, Sh.; Sari, A. H.; Hojabri, A.; Ghoranneviss, M.

2007-01-01

Nitrogen ion implantation on titanium samples performed at 3x10 18 , 8x10 17 , 3x10 18 doses. In addition CO 2 ions were also implanted at doses in the range of 1x10 17 ,4 x10 17 ,8x10 17 . Atomic Force Microscopy, used to investigate the topographical changes of implanted samples. The structure of samples and phase composition were characterized using x-ray diffraction. The results show that by increasing of nitrogen ions, the roughness, grain sizes and hardness will increase. But by further increasing of dose, hardness will be decreased. The CO 2 implantation also enhance the roughness, grain size and hardness which could be caused by phase composition.

Understanding long-term silver release from surface modified porous titanium implants.

Science.gov (United States)

Shivaram, Anish; Bose, Susmita; Bandyopadhyay, Amit

2017-08-01

Prevention of orthopedic device related infection (ODRI) using antibiotics has met with limited amount of success and is still a big concern during post-surgery. As an alternative, use of silver as an antibiotic treatment to prevent surgical infections is being used due to the well-established antimicrobial properties of silver. However, in most cases silver is used in particulate form with wound dressings or with short-term devices such as catheters but not with load-bearing implants. We hypothesize that strongly adherent silver to load-bearing implants can offer longer term solution to infection in vivo. Keeping that in mind, the focus of this study was to understand the long term release study of silver ions for a period of minimum 6months from silver coated surface modified porous titanium implants. Implants were fabricated using a LENS™ system, a powder based additive manufacturing technique, with at least 25% volume porosity, with and without TiO 2 nanotubes in phosphate buffer saline (pH 7.4) to see if the total release of silver ions is within the toxic limit for human cells. Considering the fact that infection sites may reduce the local pH, silver release was also studied in acetate buffer (pH 5.0) for a period of 4weeks. Along with that, the osseointegrative properties as well as cytotoxicity of porous titanium implants were assessed in vivo for a period of 12weeks using a rat distal femur model. In vivo results indicate that porous titanium implants with silver coating show comparable, if not better, biocompatibility and bonding at the bone-implant interface negating any concerns related to toxicity related to silver to normal cells. The current research is based on our recently patented technology, however focused on understanding longer-term silver release to mitigate infection related problems in load-bearing implants that can even arise several months after the surgery. Prevention of orthopedic device related infection using antibiotics has met

Surface modification of the titanium implant using TEA CO2 laser pulses in controllable gas atmospheres - Comparative study

International Nuclear Information System (INIS)

Ciganovic, J.; Stasic, J.; Gakovic, B.; Momcilovic, M.; Milovanovic, D.; Bokorov, M.; Trtica, M.

2012-01-01

Interaction of a TEA CO 2 laser, operating at 10.6 μm wavelength and pulse duration of 100 ns (FWHM), with a titanium implant in various gas atmospheres was studied. The Ti implant surface modification was typically studied at the moderate laser beam energy density/fluence of 28 J/cm 2 in the surrounding of air, N 2 , O 2 or He. The energy absorbed from the TEA CO 2 laser beam is partially converted to thermal energy, which generates a series of effects, such as melting, vaporization of the molten material, shock waves, etc. The following titanium implant surface changes and phenomena were observed, depending on the gas used: (i) creation of cone-like surface structures in the atmospheres of air, N 2 and O 2 , and dominant micro-holes/pores in He ambient; (ii) hydrodynamic features, most prominent in air; (iii) formation of titanium nitride and titanium oxide layers, and (iv) occurrence of plasma in front of the implant. It can be concluded from this study that the reported laser fluence and gas ambiences can effectively be applied for enhancing the titanium implant roughness and creation of titanium oxides and nitrides on the strictly localized surface area. The appearance of plasma in front of the implants indicates relatively high temperatures created above the surface. This offers a sterilizing effect, facilitating contaminant-free conditions.

Adding functionality with additive manufacturing: Fabrication of titanium-based antibiotic eluting implants.

Science.gov (United States)

Cox, Sophie C; Jamshidi, Parastoo; Eisenstein, Neil M; Webber, Mark A; Hassanin, Hany; Attallah, Moataz M; Shepherd, Duncan E T; Addison, Owen; Grover, Liam M

2016-07-01

Additive manufacturing technologies have been utilised in healthcare to create patient-specific implants. This study demonstrates the potential to add new implant functionality by further exploiting the design flexibility of these technologies. Selective laser melting was used to manufacture titanium-based (Ti-6Al-4V) implants containing a reservoir. Pore channels, connecting the implant surface to the reservoir, were incorporated to facilitate antibiotic delivery. An injectable brushite, calcium phosphate cement, was formulated as a carrier vehicle for gentamicin. Incorporation of the antibiotic significantly (p=0.01) improved the compressive strength (5.8±0.7MPa) of the cement compared to non-antibiotic samples. The controlled release of gentamicin sulphate from the calcium phosphate cement injected into the implant reservoir was demonstrated in short term elution studies using ultraviolet-visible spectroscopy. Orientation of the implant pore channels were shown, using micro-computed tomography, to impact design reproducibility and the back-pressure generated during cement injection which ultimately altered porosity. The amount of antibiotic released from all implant designs over a 6hour period (additively manufacture a titanium-based antibiotic eluting implant, which is an attractive alternative to current treatment strategies of periprosthetic infections. Copyright © 2016 Elsevier B.V. All rights reserved.

A decomposable silica-based antibacterial coating for percutaneous titanium implant

Directory of Open Access Journals (Sweden)

Wang J

2017-01-01

Full Text Available Jia Wang,1,* Guofeng Wu,2,* Xiangwei Liu,3,* Guanyang Sun,1 Dehua Li,3 Hongbo Wei3 1State Key Laboratory of Military Stomatology, National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Stomatology, Department of Prosthodontics, School of Stomatology, The Fourth Military Medical University, Xi’an, 2Department of Prosthodontics, Nanjing Stomatological Hospital, Medical School of Nanjing University, Nanjing, 3State Key Laboratory of Military Stomatology, National Clinical Research Center for Oral Diseases & Shaanxi Engineering Research Center for Dental Materials and Advanced Manufacture, Department of Oral Implants, School of Stomatology, The Fourth Military Medical University, Xi’an, People’s Republic of China *These authors contributed equally to this work Abstract: Although percutaneous titanium implants have become one of the best choices as retainers in the facial defects, peri-implantitis still occurs at a significant rate. This unwanted complication occurs due to adhesion of bacteria and subsequent biofilm formation. To solve this problem, we have developed a novel antibiotic nanodelivery system based on self-decomposable silica nanoparticles. In this study, silica-gentamycin (SG nanoparticles were successfully fabricated using an innovative one-pot solution. The nanoparticles were incorporated within a gelatin matrix and cross-linked on microarc-oxidized titanium. To characterize the SG nanoparticles, their particle size, zeta potential, surface morphology, in vitro drug release, and decomposition process were sequentially evaluated. The antibacterial properties against the gram-positive Staphylococcus aureus, including bacterial viability, antibacterial rate, and bacteria morphology, were analyzed using SG-loaded titanium specimens. Any possible influence of released gentamycin on the viability of human fibroblasts, which are the main component of soft tissues, was investigated. SG nanoparticles from the

Interactions between endothelial progenitor cells (EPC) and titanium implant surfaces.

Science.gov (United States)

Ziebart, Thomas; Schnell, Anne; Walter, Christian; Kämmerer, Peer W; Pabst, Andreas; Lehmann, Karl M; Ziebart, Johanna; Klein, Marc O; Al-Nawas, Bilal

2013-01-01

Endothelial cells play an important role in peri-implant angiogenesis during early bone formation. Therefore, interactions between endothelial progenitor cells (EPCs) and titanium dental implant surfaces are of crucial interest. The aim of our in vitro study was to investigate the reactions of EPCs in contact with different commercially available implant surfaces. EPCs from buffy coats were isolated by Ficoll density gradient separation. After cell differentiation, EPC were cultured for a period of 7 days on different titanium surfaces. The test surfaces varied in roughness and hydrophilicity: acid-etched (A), sand-blasted-blasted and acid-etched (SLA), hydrophilic A (modA), and hydrophilic SLA (modSLA). Plastic and fibronectin-coated plastic surfaces served as controls. Cell numbers and morphology were analyzed by confocal laser scanning microscopy. Secretion of vascular endothelial growth factor (VEGF)-A was measured by enzyme-linked immunosorbent assay and expressions of iNOS and eNOS were investigated by real-time polymerase chain reaction. Cell numbers were higher in the control groups compared to the cells of titanium surfaces. Initially, hydrophilic titanium surfaces (modA and modSLA) showed lower cell numbers than hydrophobic surfaces (A and SLA). After 7 days smoother surfaces (A and modA) showed increased cell numbers compared to rougher surfaces (SLA and modSLA). Cell morphology of A, modA, and control surfaces was characterized by a multitude of pseudopodia and planar cell soma architecture. SLA and modSLA promoted small and plump cell soma with little quantity of pseudopodia. The lowest VEGF level was measured on A, the highest on modSLA. The highest eNOS and iNOS expressions were found on modA surfaces. The results of this study demonstrate that biological behaviors of EPCs can be influenced by different surfaces. The modSLA surface promotes an undifferentiated phenotype of EPCs that has the ability to secrete growth factors in great quantities. In

Titanium and aluminium ions implanted by plasma on polyethylene

International Nuclear Information System (INIS)

Cruz, G.J.; Olayo, M.G.; Lopez, R.; Granda, E.; Munoz, A.; Valencia, R.; Morales, J.

2007-01-01

The ion implantation by plasma of titanium and aluminum on polyethylene thin films (PE) is presented. The results indicate that the polymers reacted firstly with the oxygen and/or nitrogen carrying gases, and later its received the metallic particles that formed thin films. The stainless steel and the titanium formed a single phase. The metallic layers grew in the interval of 1 to 2 nm/min, its are thin, but enough to change the hardness of the polymer that it is increased in more of 20 times. (Author)

Influence of the implant-abutment connection design and diameter on the screw joint stability

Science.gov (United States)

Shin, Hyon-Mo; Huh, Jung-Bo; Yun, Mi-Jeong; Jeon, Young-Chan; Chang, Brian Myung

2014-01-01

PURPOSE This study was conducted to evaluate the influence of the implant-abutment connection design and diameter on the screw joint stability. MATERIALS AND METHODS Regular and wide-diameter implant systems with three different joint connection designs: an external butt joint, a one-stage internal cone, and a two-stage internal cone were divided into seven groups (n=5, in each group). The initial removal torque values of the abutment screw were measured with a digital torque gauge. The postload removal torque values were measured after 100,000 cycles of a 150 N and a 10 Hz cyclic load had been applied. Subsequently, the rates of the initial and postload removal torque losses were calculated to evaluate the effect of the joint connection design and diameter on the screw joint stability. Each group was compared using Kruskal-Wallis test and Mann-Whitney U test as post-hoc test (α=0.05). RESULTS The postload removal torque value was high in the following order with regard to magnitude: two-stage internal cone, one-stage internal cone, and external butt joint systems. In the regular-diameter group, the external butt joint and one-stage internal cone systems showed lower postload removal torque loss rates than the two-stage internal cone system. In the wide-diameter group, the external butt joint system showed a lower loss rate than the one-stage internal cone and two-stage internal cone systems. In the two-stage internal cone system, the wide-diameter group showed a significantly lower loss rate than the regular-diameter group (P<.05). CONCLUSION The results of this study showed that the external butt joint was more advantageous than the internal cone in terms of the postload removal torque loss. For the difference in the implant diameter, a wide diameter was more advantageous in terms of the torque loss rate. PMID:24843398

Influence of the implant-abutment connection design and diameter on the screw joint stability.

Science.gov (United States)

Shin, Hyon-Mo; Huh, Jung-Bo; Yun, Mi-Jeong; Jeon, Young-Chan; Chang, Brian Myung; Jeong, Chang-Mo

2014-04-01

This study was conducted to evaluate the influence of the implant-abutment connection design and diameter on the screw joint stability. Regular and wide-diameter implant systems with three different joint connection designs: an external butt joint, a one-stage internal cone, and a two-stage internal cone were divided into seven groups (n=5, in each group). The initial removal torque values of the abutment screw were measured with a digital torque gauge. The postload removal torque values were measured after 100,000 cycles of a 150 N and a 10 Hz cyclic load had been applied. Subsequently, the rates of the initial and postload removal torque losses were calculated to evaluate the effect of the joint connection design and diameter on the screw joint stability. Each group was compared using Kruskal-Wallis test and Mann-Whitney U test as post-hoc test (α=0.05). THE POSTLOAD REMOVAL TORQUE VALUE WAS HIGH IN THE FOLLOWING ORDER WITH REGARD TO MAGNITUDE: two-stage internal cone, one-stage internal cone, and external butt joint systems. In the regular-diameter group, the external butt joint and one-stage internal cone systems showed lower postload removal torque loss rates than the two-stage internal cone system. In the wide-diameter group, the external butt joint system showed a lower loss rate than the one-stage internal cone and two-stage internal cone systems. In the two-stage internal cone system, the wide-diameter group showed a significantly lower loss rate than the regular-diameter group (P<.05). The results of this study showed that the external butt joint was more advantageous than the internal cone in terms of the postload removal torque loss. For the difference in the implant diameter, a wide diameter was more advantageous in terms of the torque loss rate.

Strategies For Immobilization Of Bioactive Organic Molecules On Titanium Implant Surfaces – A Review

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Panayotov Ivan V.

2015-03-01

Full Text Available Numerous approaches have been used to improve the tissue-implant interface of titanium (Ti and titanium alloy (Ti6Al4V. They all aim at increasing cell migration and attachment to the metal, preventing unspecific protein adsorption and improving post-implantation healing process. Promising methods for titanium and titanium alloy surface modification are based on the immobilization of biologically active organic molecules. New and interesting biochemical approaches to such surface modification include layer-by-layer deposition of polyelectrolyte films, phage display-selected surface binding peptides and self-assembled DNA monolayer systems. The present review summarizes the scientific information about these methods, which are at in vitro or in vivo development stages, and hopes to promote their future application in dental implantology and in oral and maxillofacial surgery.

Effects of pore size, implantation time and nano-surface properties on rat skin ingrowth into percutaneous porous titanium implants

OpenAIRE

Farrell, Brad J.; Prilutsky, Boris I.; Ritter, Jana M.; Kelley, Sean; Popat, Ketul; Pitkin, Mark

2013-01-01

The main problem of percutaneous osseointegrated implants is poor skin-implant integration, which may cause infection. This study investigated the effects of pore size (Small, 40–100 microns and Large, 100–160 microns), nanotubular surface treatment (Nano), and duration of implantation (3 and 6 weeks) on skin ingrowth into porous titanium. Each implant type was percutaneously inserted in the back of 35 rats randomly assigned to 7 groups. Implant extrusion rate was measured w...

Repair of microdamage in osteonal cortical bone adjacent to bone screw.

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Lei Wang

Full Text Available Up to date, little is known about the repair mode of microdamage in osteonal cortical bone resulting from bone screw implantation. In this study, self-tapping titanium cortical bone screws were inserted into the tibial diaphyses of 24 adult male rabbits. The animals were sacrificed at 1 day, 2 weeks, 1 month and 2 months after surgery. Histomorphometric measurement and confocal microscopy were performed on basic fuchsin stained bone sections to examine the morphological characteristics of microdamage, bone resorption activity and spatial relationship between microdamage and bone resorption. Diffuse and linear cracks were coexisted in peri-screw bone. Intracortical bone resorption was significantly increased 2 weeks after screw installation and reach to the maximum at 1 month. There was no significant difference in bone resorption between 1-month and 2-months groups. Microdamage was significantly decreased within 1 month after surgery. Bone resorption was predisposed to occur in the region of <100 µm from the bone-screw interface, where had extensive diffuse damage mixed with linear cracks. Different patterns of resorption cavities appeared in peri-screw bone. These data suggest that 1 the complex microdamage composed of diffuse damage and linear cracks is a strong stimulator for initiating targeted bone remodeling; 2 bone resorption activities taking place on the surfaces of differently oriented Haversian and Volkmann canals work in a team for the repair of extensive microdamage; 3 targeted bone remodeling is a short-term reaction to microdamage and thereby it may not be able to remove all microdamage resulting from bone screw insertion.

One-year results of maxillary overdentures supported by 2 titanium-zirconium implants - implant survival rates and radiographic outcomes.

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Zembic, Anja; Tahmaseb, Ali; Jung, Ronald E; Wismeijer, Daniel

2017-07-01

To assess implant survival rates and peri-implant bone loss of 2 titanium-zirconium implants supporting maxillary overdentures at 1 year of loading. Twenty maxillary edentulous patients (5 women and 15 men) being dissatisfied with their complete dentures were included. In total, 40 diameter-reduced titanium-zirconium implants were placed in the anterior maxilla. Local guided bone regeneration (GBR) was allowed if the treatment did not compromise implant stability. Following 3 to 5 months of healing, implant-supported overdentures were inserted on two ball anchors. Implants and overdentures were assessed at 1, 2, 4, and 8 weeks after implant insertion and 2, 4, and 12 months after insertion of overdentures (baseline). Standardized radiographs were taken at implant loading and 1 year. Implant survival rates and bone loss were the primary outcomes. Nineteen patients (1 dropout) with 38 implants were evaluated at a mean follow-up of 1.1 years (range 1.0-1.7 years). One implant failed resulting in an implant survival rate of 97.3%. There was a significant peri-implant bone loss of the implants at 1 year of function (mean, 0.7 mm, SD = 1.1 mm; median: 0.48 mm, IQR = 0.56 mm). There was a high 1-year implant survival rate for edentulous patients receiving 2 maxillary implants and ball anchors as overdenture support. However, several implants exhibited an increased amount of bone loss of more than 2 mm. Overdentures supported by 2 maxillary implants should thus be used with caution as minimally invasive treatment for specific patients encountering problems with their upper dentures until more long-term data is available. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Mechanical verification of soft-tissue attachment on bioactive glasses and titanium implants.

Science.gov (United States)

Zhao, Desheng; Moritz, Niko; Vedel, Erik; Hupa, Leena; Aro, Hannu T

2008-07-01

Soft-tissue attachment is a desired feature of many clinical biomaterials. The aim of the current study was to design a suitable experimental method for tensile testing of implant incorporation with soft-tissues. Conical implants were made of three compositions of bioactive glass (SiO(2)-P(2)O(5)-B(2)O(3)-Na(2)O-K(2)O-CaO-MgO) or titanium fiber mesh (porosity 84.7%). The implants were surgically inserted into the dorsal subcutaneous soft-tissue or back muscles in the rat. Soft-tissue attachment was evaluated by pull-out testing using a custom-made jig 8 weeks after implantation. Titanium fiber mesh implants had developed a relatively high pull-out force in subcutaneous tissue (12.33+/-5.29 N, mean+/-SD) and also measurable attachment with muscle tissue (2.46+/-1.33 N). The bioactive glass implants failed to show mechanically relevant soft-tissue bonding. The experimental set-up of mechanical testing seems to be feasible for verification studies of soft-tissue attachment. The inexpensive small animal model is beneficial for large-scale in vivo screening of new biomaterials.

Assessment of modified gold surfaced titanium implants on skeletal fixation

DEFF Research Database (Denmark)

Zainali, Kasra; Danscher, Gorm; Jakobsen, Thomas

2013-01-01

shown to liberate gold ions through the process termed dissolucytosis. Furthermore, gold ions are known to act in an anti-inflammatory manner by inhibiting cellular NF-κB-DNA binding. The present study investigated whether partial coating of titanium implants could augment early osseointegration...... and increase mechanical fixation. Cylindrical porous coated Ti-6Al4V implants partially coated with metallic gold were inserted in the proximal region of the humerus in ten canines and control implants without gold were inserted in contralateral humerus. Observation time was 4 weeks. Biomechanical push out...

Reconstruction with a patient-specific titanium implant after a wide anterior chest wall resection

Science.gov (United States)

Turna, Akif; Kavakli, Kuthan; Sapmaz, Ersin; Arslan, Hakan; Caylak, Hasan; Gokce, Hasan Suat; Demirkaya, Ahmet

2014-01-01

The reconstruction of full-thickness chest wall defects is a challenging problem for thoracic surgeons, particularly after a wide resection of the chest wall that includes the sternum. The location and the size of the defect play a major role when selecting the method of reconstruction, while acceptable cosmetic and functional results remain the primary goal. Improvements in preoperative imaging techniques and reconstruction materials have an important role when planning and performing a wide chest wall resection with a low morbidity rate. In this report, we describe the reconstruction of a wide anterior chest wall defect with a patient-specific custom-made titanium implant. An infected mammary tumour recurrence in a 62-year old female, located at the anterior chest wall including the sternum, was resected, followed by a large custom-made titanium implant. Latissimus dorsi flap and split-thickness graft were also used for covering the implant successfully. A titanium custom-made chest wall implant could be a viable alternative for patients who had large chest wall tumours. PMID:24227881

Adapted preparation technique for screw-type implants: explorative in vitro pilot study in a porcine bone model.

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Beer, Andreas; Gahleitner, André; Holm, Anders; Birkfellner, Wolfgang; Homolka, Peter

2007-02-01

The aim of this study was to quantify the effect of adapted preparation on the insertion torque of self-tapping implants in cancellous bone. In adapted preparation, bone condensation - and thus, insertion torque - is controlled by changing the diameter of the drilling. After preparation of cancellous porcine vertebral bone with drills of 2.85, 3, 3.15 or 3.35 mm final diameters, Brånemark sytem Mk III implants (3.75 x 11.5 mm) were inserted in 141 sites. During implantation, the insertion torque was recorded. Prior to implant insertion, bone mineralization (bone mineral density (BMD)) was measured with dental quantative computed tomography. The BMD values measured at the implant position were correlated with insertion torque for varying bone condensation. Based on the average torque recorded during implant insertion into the pre-drilled canals with a diameter of 3 mm, torque increased by approximately 17% on reducing the diameter of the drill by 5% (to 2.85 mm). On increasing the diameter of the osteotomy to 3.15 mm (5%) or 3.35 mm (12%), torque values decreased by approximately 21% and 50%, respectively. The results demonstrate a correlation between primary stability (average insertion torque) and the diameter of the implant bed on using a screw-shaped implant. Thus, using an individualized bone mineralization-dependent drilling technique, optimized torque values could be achieved in all tested bone qualities with BMDs ranging from 330 to 500 mg/cm(3). The results indicate that using a bone-dependent drilling technique, higher torque values can also be achieved in poor bone using an individualized drilling resulting in higher bone condensation. As immediate function is dependent on primary stability (high insertion torque), this indicates that primary stability can be increased using a modified drilling technique in lesser mineralized bone.

Shallow nitrogen ion implantation: Evolution of chemical state and defect structure in titanium

Energy Technology Data Exchange (ETDEWEB)

Manojkumar, P.A., E-mail: manoj@igcar.gov.in [Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India); Chirayath, V.A.; Balamurugan, A.K.; Krishna, Nanda Gopala; Ilango, S.; Kamruddin, M.; Amarendra, G.; Tyagi, A.K. [Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India); Raj, Baldev [National Institute of Advanced Studies, Bangalore 560 012 (India)

2016-09-15

Highlights: • Low energy nitrogen ion implantation in titanium was studied. • Chemical and defect states were analyzed using SIMS, XPS and PAS. • SIMS and depth resolved XPS data showed good agreement. • Depth resolved defect and chemical states information were revealed. • Formation of 3 layers of defect states proposed to fit PAS results. - Abstract: Evolution of chemical states and defect structure in titanium during low energy nitrogen ion implantation by Plasma Immersion Ion Implantation (PIII) process is studied. The underlying process of chemical state evolution is investigated using secondary ion mass spectrometry and X-ray photoelectron spectroscopy. The implantation induced defect structure evolution as a function of dose is elucidated using variable energy positron annihilation Doppler broadening spectroscopy (PAS) and the results were corroborated with chemical state. Formation of 3 layers of defect state was modeled to fit PAS results.

Electrochemical assessment of some titanium and stainless steel impact dental alloys

International Nuclear Information System (INIS)

Echavarria, A.; Arroyave, C.

2003-01-01

Commercially pure titanium alloy, Ti-6Al-4V alloy and stainless steel screw implants were evaluated in both Ringer and synthetic saliva physiological solutions at body temperature by EIS (Electrochemical Impedance Spectroscopy) with immersion times of 30 d. Results were simulated as a sandwich system composed by four capacitors-resistances connected in series with the solution resistance. A model explaining the results in terms of the porosity and thickness of four different layers, was proposed. (Author) 22 refs

Alkalescent nanotube films on a titanium-based implant: A novel approach to enhance biocompatibility

Energy Technology Data Exchange (ETDEWEB)

Zhang, Yanxian [Corrosion and Protection Center, Key Laboratory for Corrosion and Protection (MOE), University of Science and Technology Beijing, Beijing 100083 (China); Dong, Chaofang, E-mail: cfdong@ustb.edu.cn [Corrosion and Protection Center, Key Laboratory for Corrosion and Protection (MOE), University of Science and Technology Beijing, Beijing 100083 (China); Yang, Sefei [Department of Stomatology, The PLA General Hospital, Beijing 100853 (China); Wu, Junsheng; Xiao, Kui; Huang, Yunhua; Li, Xiaogang [Corrosion and Protection Center, Key Laboratory for Corrosion and Protection (MOE), University of Science and Technology Beijing, Beijing 100083 (China)

2017-03-01

The interfacial pH value has a marked effect on cell viability because the pro-mineralization activity of osteoblasts increases at alkaline extracellular pH, whereas the pro-resorptive activity of osteoclasts increases under more acidic conditions. To obtain the more favorable alkaline interface, we developed a novel nanotube layer that was incorporated with magnesium oxide on a titanium implant substrate (MgO/NT/Ti) via ethylenediamine tetraacetic acid (EDTA) chelation. This facile immersion-annealing process successfully created a homogeneous magnesium oxide layer with sustained release kinetics and superior hydrophilicity according to the surface characterization and microenvironment measurement. The titania nanotubes on the substrate with an anatase phase exhibited a lower passivation current and a more positive corrosion potential compared with pure titanium, which guaranteed a reasonable corrosion resistance, even when it was wrapped with a magnesium oxide layer. In vitro cell cultures showed that MgO/NT/Ti significantly increased cell proliferation and alkaline phosphatase (ALP) activity. The resulting alkalescent microenvironment created by the MgO layer encouraged the cells to spread into polygonal shapes, accelerated the differentiation stage to osteoblast and induced a higher expression of vinculin. In summary, the incorporated alkalescent microenvironment of MgO/NT/Ti provided a viable approach to stimulate cell proliferation, adhesion, and differentiation and to improve the implant osseointegration. - Highlights: • We developed a novel nanotube layer incorporated with magnesium oxide to obtain a favorable alkaline interface. • The homogeneous magnesium oxide layer exhibited sustained release kinetics. • The resulting alkalescent microenvironment provided a viable approach to improve the implant osseointegration.

Evaluation of torque loss value of MAD/MAM zirconia abutments with prefabricated titanium abutments

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Marzieh Alikhasi

2013-04-01

Full Text Available Background and Aims: In response to esthetic demand of patients, ceramic abutments have been developed. Despite esthetic of zirconia abutments, machining accuracy of these abutments has always been a question. Any misfit in the abutment-implant interface connection can lead to detorque and screw loosening. The aim of this study was to compare torque loss value of manually aided design/manually aided manufacture (MAD/MAM zirconia abutments with prefabricated titanium abutments. Materials and Methods: Seven titanium abutments (Branemark RP, Easy abutment and seven copy milled abutments which were duplicated from the prefabricated Zirkonzhan (ZirkonZahn, Sand in Taufers, Italy were prepared. After sintering process of zirconia abutment, all abutments were fastened with a torque screw under 35 Ncm. Detorque measurements were performed per group pushing the reverse button of the Torque controller soon after screw tightening with values registered. The mean torque loss were calculated and compared using Student's t test. Results: The mean of torque loss was 12.71 Ncm with standard deviation of 1.70 for prefabricated titanium abutments and 15.50 Ncm with standard deviation of 4.67 for MAD-MAM abutments. The difference between the two groups was not statistically significant (P=0.23. Conclusion: Within the limitation of this study, MAD-MAM ceramic abutments could maintain the applied torque comparing to the prefabricated abutments.

Effect of pore size on bone ingrowth into porous titanium implants fabricated by additive manufacturing: An in vivo experiment.

Science.gov (United States)

Taniguchi, Naoya; Fujibayashi, Shunsuke; Takemoto, Mitsuru; Sasaki, Kiyoyuki; Otsuki, Bungo; Nakamura, Takashi; Matsushita, Tomiharu; Kokubo, Tadashi; Matsuda, Shuichi

2016-02-01

Selective laser melting (SLM) is an additive manufacturing technique with the ability to produce metallic scaffolds with accurately controlled pore size, porosity, and interconnectivity for orthopedic applications. However, the optimal pore structure of porous titanium manufactured by SLM remains unclear. In this study, we evaluated the effect of pore size with constant porosity on in vivo bone ingrowth in rabbits into porous titanium implants manufactured by SLM. Three porous titanium implants (with an intended porosity of 65% and pore sizes of 300, 600, and 900μm, designated the P300, P600, and P900 implants, respectively) were manufactured by SLM. A diamond lattice was adapted as the basic structure. Their porous structures were evaluated and verified using microfocus X-ray computed tomography. Their bone-implant fixation ability was evaluated by their implantation as porous-surfaced titanium plates into the cortical bone of the rabbit tibia. Bone ingrowth was evaluated by their implantation as cylindrical porous titanium implants into the cancellous bone of the rabbit femur for 2, 4, and 8weeks. The average pore sizes of the P300, P600, and P900 implants were 309, 632, and 956μm, respectively. The P600 implant demonstrated a significantly higher fixation ability at 2weeks than the other implants. After 4weeks, all models had sufficiently high fixation ability in a detaching test. Bone ingrowth into the P300 implant was lower than into the other implants at 4weeks. Because of its appropriate mechanical strength, high fixation ability, and rapid bone ingrowth, our results indicate that the pore structure of the P600 implant is a suitable porous structure for orthopedic implants manufactured by SLM. Copyright © 2015 Elsevier B.V. All rights reserved.

Plasma Electrolytic Oxidation of Titanium Implant Surfaces: Microgroove-Structures Improve Cellular Adhesion and Viability.

Science.gov (United States)

Hartjen, Philip; Hoffmann, Alexia; Henningsen, Anders; Barbeck, Mike; Kopp, Alexander; Kluwe, Lan; Precht, Clarissa; Quatela, Olivia; Gaudin, Robert; Heiland, Max; Friedrich, Reinhard E; Knipfer, Christian; Grubeanu, Daniel; Smeets, Ralf; Jung, Ole

2018-01-01

Plasma electrolytic oxidation (PEO) is an established electrochemical treatment technique that can be used for surface modifications of metal implants. In this study we to treated titanium implants with PEO, to examine the resulting microstructure and to characterize adhesion and viability of cells on the treated surfaces. Our aim was to identify an optimal surface-modification for titanium implants in order to improve soft-tissue integration. Three surface-variants were generated on titanium alloy Ti6Al4V by PEO-treatment. The elemental composition and the microstructures of the surfaces were characterized using energy dispersive X-ray spectroscopy, scanning electron microscopy and profilometry. In vitro cytocompatibility of the surfaces was assessed by seeding L929 fibroblasts onto them and measuring the adhesion, viability and cytotoxicity of cells by means of live/dead staining, XTT assay and LDH assay. Electron microscopy and profilometry revealed that the PEO-surface variants differed largely in microstructure/topography, porosity and roughness from the untreated control material as well as from one another. Roughness was generally increased after PEO-treatment. In vitro, PEO-treatment led to improved cellular adhesion and viability of cells accompanied by decreased cytotoxicity. PEO-treatment provides a promising strategy to improve the integration of titanium implants with surrounding tissues. Copyright© 2018, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

[Mid-Term Clinical Results after Open Rotator Cuff Reconstruction in Double-Row Technique with Titanium Anchor Screws].

Science.gov (United States)

Geyer, S; Schoch, C; Nelitz, M; Geyer, M

2015-08-01

The double-row rotator cuff repair is discussed controversially. Despite improved biomechanical properties, reduced re-tear rates and higher costs, no significant difference compared to single-row fixation in the clinical results is found. Mid-term results of an open double-row fixation with titanium anchor screws are presented. 237 patients (m = 142, f = 95, median age: 56.3 years) were operated in 2007 with this technique by the senior author (M. G.). Preoperatively, 2 years and 4,5 years postoperatively a subjective shoulder score (SSG) with follow-up rates of 86, 87 and 83 %, was evaluated. 5.1 years postoperatively an objective evaluation of 131 patients using the Constant-Murley scores (CS), the simple shoulder tests (SST), Gerber's shoulder value and the evaluation with school grades followed. The integrity of the cuff was checked with ultrasound. The absolute (re-tears and partial re-tears) and the relative (re-tears, partial re-tears, thinning and thickening of the cuff) re-tear rates were evaluated. In SSG a highly significant improvement from 51 to 83 points was found (p row cuff repair with titanium screws is a safe and cost effective technique with a low re-tear rate with comparable clinical results regarding open and arthroscopic procedures. Georg Thieme Verlag KG Stuttgart · New York.

Bite Reconstruction in the Aesthetic Zone Using One-Piece Bicortical Screw Implants

Directory of Open Access Journals (Sweden)

Stefan Ihde

2018-01-01

Full Text Available The aim of this article was to present the clinical application of a new, smooth surfaced one-piece bicortical screw implant with immediate loading protocol. An 18-year-old, healthy male patient with a history of total dislocation and replantation of teeth 11 and 21 in early childhood was admitted to the clinic. Teeth 11 and 21 were extracted, and two long one-piece implants were inserted at extraction sockets in one surgical session under local anesthesia. Temporary composite crowns were placed in the patient on the same day. After 3 months, the single-phase two-layer impression was made and the composite crowns were replaced with metal-ceramic crowns. After 12 months, satisfactory aesthetic and functional results were obtained.

Poly-ε-caprolactone Coated and Functionalized Porous Titanium and Magnesium Implants for Enhancing Angiogenesis in Critically Sized Bone Defects.

Science.gov (United States)

Roland, Laura; Grau, Michael; Matena, Julia; Teske, Michael; Gieseke, Matthias; Kampmann, Andreas; Beyerbach, Martin; Murua Escobar, Hugo; Haferkamp, Heinz; Gellrich, Nils-Claudius; Nolte, Ingo

2015-12-22

For healing of critically sized bone defects, biocompatible and angiogenesis supporting implants are favorable. Murine osteoblasts showed equal proliferation behavior on the polymers poly-ε-caprolactone (PCL) and poly-(3-hydroxybutyrate)/poly-(4-hydroxybutyrate) (P(3HB)/P(4HB)). As vitality was significantly better for PCL, it was chosen as a suitable coating material for further experiments. Titanium implants with 600 µm pore size were evaluated and found to be a good implant material for bone, as primary osteoblasts showed a vitality and proliferation onto the implants comparable to well bottom (WB). Pure porous titanium implants and PCL coated porous titanium implants were compared using Live Cell Imaging (LCI) with Green fluorescent protein (GFP)-osteoblasts. Cell count and cell covered area did not differ between the implants after seven days. To improve ingrowth of blood vessels into porous implants, proangiogenic factors like Vascular Endothelial Growth Factor (VEGF) and High Mobility Group Box 1 (HMGB1) were incorporated into PCL coated, porous titanium and magnesium implants. An angiogenesis assay was performed to establish an in vitro method for evaluating the impact of metallic implants on angiogenesis to reduce and refine animal experiments in future. Incorporated concentrations of proangiogenic factors were probably too low, as they did not lead to any effect. Magnesium implants did not yield evaluable results, as they led to pH increase and subsequent cell death.

Comparison of biological characteristics of mesenchymal stem cells grown on two different titanium implant surfaces

International Nuclear Information System (INIS)

Wang Chengyue; Zhao Baohong; Ai Hongjun; Wang Yiwei

2008-01-01

This study examined the biological characteristics of mesenchymal stem cells (MSCs) grown on sand-blasted, large-grit, acid-etched (SLA) surface and hydroxyapatite (HA) coating on the SLA (HA/SLA) surface of titanium dental implants. The HA/SLA surfaces of titanium dental implants were formed by the ion beam assisted deposition (IBAD) method. Rabbit bone marrow derived mesenchymal stem cells cultured in vitro were seeded onto the surface of SLA and HA/SLA; the growth states of MSCs on the two samples were observed by a scanning electron microscope; the proliferation index, alkaline phosphatase (ALP) activity, osteocalcin (OCN) content of MSCs and mRNA relative expression level of osteopontin (opn) were compared between two groups. MSCs were found to be easier to adhere to the HA/SLA surface compared to the SLA surface. At the same time, the ALP activity and the OCN content of MSCs grown on the HA/SLA surface were obviously higher, and the relative expression level of opn mRNA was 4.78 times higher than that on the SLA surface. The HA coating formed by the IBAD method on the SLA surface of titanium dental implants significantly improves proliferation and well-differentiated osteoblastic phenotype of MSCs, which indicates a promising method for the surface modification of titanium dental implants

Effect of ion-implantation on surface characteristics of nickel titanium and titanium molybdenum alloy arch wires

Directory of Open Access Journals (Sweden)

Manu Krishnan

2013-01-01

Full Text Available Aim: To evaluate the changes in surface roughness and frictional features of ′ion-implanted nickel titanium (NiTi and titanium molybdenum alloy (TMA arch wires′ from its conventional types in an in-vitro laboratory set up. Materials and Methods: ′Ion-implanted NiTi and low friction TMA arch wires′ were assessed for surface roughness with scanning electron microscopy (SEM and 3 dimensional (3D optical profilometry. Frictional forces were studied in a universal testing machine. Surface roughness of arch wires were determined as Root Mean Square (RMS values in nanometers and Frictional Forces (FF in grams. Statistical Analysis Used: Mean values of RMS and FF were compared by Student′s ′t′ test and one way analysis of variance (ANOVA. Results: SEM images showed a smooth topography for ion-implanted versions. 3D optical profilometry demonstrated reduction of RMS values by 58.43% for ion-implanted NiTi (795.95 to 330.87 nm and 48.90% for TMA groups (463.28 to 236.35 nm from controls. Nonetheless, the corresponding decrease in FF was only 29.18% for NiTi and 22.04% for TMA, suggesting partial correction of surface roughness and disproportionate reduction in frictional forces with ion-implantation. Though the reductions were highly significant at P < 0.001, relations between surface roughness and frictional forces remained non conclusive even after ion-implantation. Conclusion: The study proved that ion-implantation can significantly reduce the surface roughness of NiTi and TMA wires but could not make a similar reduction in frictional forces. This can be attributed to the inherent differences in stiffness and surface reactivity of NiTi and TMA wires when used in combination with stainless steel brackets, which needs further investigations.

Bone Morphogenetic Protein Coating on Titanium Implant Surface: a Systematic Review

Directory of Open Access Journals (Sweden)

Haim Haimov

2017-06-01

Full Text Available Objectives: The purpose of the study is to systematically review the osseointegration process improvement by bone morphogenetic protein coating on titanium implant surface. Material and Methods: An electronic literature search was conducted through the MEDLINE (PubMed and EMBASE databases. The search was restricted for articles published during the last 10 years from October 2006 to September 2016 and articles were limited to English language. Results: A total of 41 articles were reviewed, and 8 of the most relevant articles that are suitable to the criteria were selected. Articles were analysed regarding concentration of bone morphogenetic protein (BMP, delivery systems, adverse reactions and the influence of the BMP on the bone and peri-implant surface in vivo. Finally, the present data included 340 implants and 236 models. Conclusions: It’s clearly shown from most of the examined studies that bone morphogenetic protein increases bone regeneration. Further studies should be done in order to induce and sustain bone formation activity. Osteogenic agent should be gradually liberated and not rapidly released with priority to three-dimension reservoir (incorporated titanium implant surface in order to avoid following severe side effects: inflammation, bleeding, haematoma, oedema, erythema, and graft failure.

No positive effect of Acid etching or plasma cleaning on osseointegration of titanium implants in a canine femoral condyle press-fit model

DEFF Research Database (Denmark)

Saksø, Henrik; Jakobsen, Thomas Vestergaard; Mortensen, Mikkel Saksø

2013-01-01

Implant surface treatments that improve early osseointegration may prove useful in long-term survival of uncemented implants. We investigated Acid Etching and Plasma Cleaning on titanium implants.......Implant surface treatments that improve early osseointegration may prove useful in long-term survival of uncemented implants. We investigated Acid Etching and Plasma Cleaning on titanium implants....

Preservation and release dose of helium implanted in nanocrystal titanium film

International Nuclear Information System (INIS)

Long Xinggui; Luo Shunzhong; Peng Shuming; Zheng Sixiao; Liu Zhongyang; Wang Peilu; Liao Xiaodong; Liu Ning

2003-01-01

Helium concentration profile, preservation dose and release rate from a nanocrystal titanium film implanted with helium at an energy of 100 keV and dose of 2.2 x 10 18 cm -2 are measured by proton Rutherford backscattering technique in a range from room temperature to 400 degree C. The implanted helium may be stably preserved up to the 68 percent after keeping a long time of 210 d in the nanocrystal titanium film at the room temperature environment, and the He-Ti atomic ratio reaches to 52.6%. When the temperature of specimen increases to 100 degree C, the helium concentration can be preserved to 89.6% of the keeping helium dose at room temperature and He-Ti atomic ratio reaches 44%. Even if the specimen temperature up to 400 degree C, the helium concentration still can be preserved to 32.6% of the keeping helium dose at room temperature and the He-Ti atomic ratio is 17.1%. Possible mechanism of helium effectively preserved in the nanocrystal titanium film is discussed based on the energy stability viewpoint

Clinical performance of provisional screw-retained metal-free acrylic restorations in an immediate loading implant protocol: a 242 consecutive patients' report.

Science.gov (United States)

Suarez-Feito, Jose-María; Sicilia, Alberto; Angulo, Jorge; Banerji, Subir; Cuesta, Isabel; Millar, Brian

2010-12-01

To evaluate the clinical performance of provisional screw-retained metal-free acrylic restorations in an immediate loading implant protocol. Two hundred and forty-two consecutive patients were selected retrospectively, who received 1011 implants and 311 immediate provisional screw-retained implant restorations (2-4 h after implant surgery). The patients were monitored for a period of 2-3 months, until they were referred for a final restoration. The primary variables recorded include the survival time and the appearance of fractures in the provisional restoration, and the independent variables included age, sex, dental arch, type of restoration, type of attachment and components used, as well as cantilevers and opposing dentition. A survival analysis (Kaplan-Meier) and a Cox regression analysis were performed. Twenty-three restorations in 20 patients (8.26%, 95% CI 4.8-11.7) showed at least one fracture (7.39%). More than half of the new fractures (52%, 12 cases) occurred in the first 4 weeks. The cumulative survival probability observed was greater in mandible (P=0.05) and non-cantilever restorations (P=0.001), and in those opposed by full restorations or natural teeth (P=0.001). With an opposing implant-supported prosthesis, the risk of fracture was multiplied by 4.7, and the use of cantilevers as well as the location of the restoration in the maxilla multiply the risk by 3.4-3.5. Immediate provisional screw-retained metal-free implant-supported restorations can be considered a reliable restoration (92.6% remain intact) for the healing period of 3 months. © 2010 John Wiley & Sons A/S.

A preliminary study on investigating the attachment of soft tissue onto micro-arc oxidized titanium alloy implants

International Nuclear Information System (INIS)

Chen, G J; Wang, Z; Bai, H; Li, J M; Cai, H

2009-01-01

Intraosseous transcutaneous amputation prostheses (ITAP) rely on the integrity of the soft tissue-implant interface as a barrier to exogenous agents, and in the prevention of avulsion and marsupilization. This experimental work aimed at the in vivo evaluation of soft tissue attachment to Ti alloy (Ti 6 Al 4 V) transcutaneous custom-made screws treated by a micro-arc oxidation (MAO) method. Prior to implantation, the surface of the MAO treated implants was analyzed by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and x-ray diffraction (XRD). The experimental model comprised implantation of 16 transcutaneous screws (two groups: MAO and machined (control); total eight implants/group) in the medial aspect of the left tibia of eight female goats. The animals were euthanized at eight weeks and the samples harvested and processed for histological and histomorphometrical analysis of soft tissue attachment to the implant surface. Significant higher soft tissue attachment was observed in the MAO-modified group compared to the control. The in vivo data indicated that MAO-modified Ti alloy could be a useful biomaterial for tissue engineering and benefit applications where bone-anchored transcutaneous implants are used.

Modulating macrophage polarization with divalent cations in nanostructured titanium implant surfaces

International Nuclear Information System (INIS)

Lee, Chung-Ho; Kim, Youn-Jeong; Jang, Je-Hee; Park, Jin-Woo

2016-01-01

Nanoscale topographical modification and surface chemistry alteration using bioactive ions are centrally important processes in the current design of the surface of titanium (Ti) bone implants with enhanced bone healing capacity. Macrophages play a central role in the early tissue healing stage and their activity in response to the implant surface is known to affect the subsequent healing outcome. Thus, the positive modulation of macrophage phenotype polarization (i.e. towards the regenerative M2 rather than the inflammatory M1 phenotype) with a modified surface is essential for the osteogenesis funtion of Ti bone implants. However, relatively few advances have been made in terms of modulating the macrophage-centered early healing capacity in the surface design of Ti bone implants for the two important surface properties of nanotopography and and bioactive ion chemistry. We investigated whether surface bioactive ion modification exerts a definite beneficial effect on inducing regenerative M2 macrophage polarization when combined with the surface nanotopography of Ti. Our results indicate that nanoscale topographical modification and surface bioactive ion chemistry can positively modulate the macrophage phenotype in a Ti implant surface. To the best of our knowledge, this is the first demonstration that chemical surface modification using divalent cations (Ca and Sr) dramatically induces the regenerative M2 macrophage phenotype of J774.A1 cells in nanostructured Ti surfaces. In this study, divalent cation chemistry regulated the cell shape of adherent macrophages and markedly up-regulated M2 macrophage phenotype expression when combined with the nanostructured Ti surface. These results provide insight into the surface engineering of future Ti bone implants that are harmonized between the macrophage-governed early wound healing process and subsequent mesenchymal stem cell-centered osteogenesis function. (paper)

Modulating macrophage polarization with divalent cations in nanostructured titanium implant surfaces

Science.gov (United States)

Lee, Chung-Ho; Kim, Youn-Jeong; Jang, Je-Hee; Park, Jin-Woo

2016-02-01

Nanoscale topographical modification and surface chemistry alteration using bioactive ions are centrally important processes in the current design of the surface of titanium (Ti) bone implants with enhanced bone healing capacity. Macrophages play a central role in the early tissue healing stage and their activity in response to the implant surface is known to affect the subsequent healing outcome. Thus, the positive modulation of macrophage phenotype polarization (i.e. towards the regenerative M2 rather than the inflammatory M1 phenotype) with a modified surface is essential for the osteogenesis funtion of Ti bone implants. However, relatively few advances have been made in terms of modulating the macrophage-centered early healing capacity in the surface design of Ti bone implants for the two important surface properties of nanotopography and and bioactive ion chemistry. We investigated whether surface bioactive ion modification exerts a definite beneficial effect on inducing regenerative M2 macrophage polarization when combined with the surface nanotopography of Ti. Our results indicate that nanoscale topographical modification and surface bioactive ion chemistry can positively modulate the macrophage phenotype in a Ti implant surface. To the best of our knowledge, this is the first demonstration that chemical surface modification using divalent cations (Ca and Sr) dramatically induces the regenerative M2 macrophage phenotype of J774.A1 cells in nanostructured Ti surfaces. In this study, divalent cation chemistry regulated the cell shape of adherent macrophages and markedly up-regulated M2 macrophage phenotype expression when combined with the nanostructured Ti surface. These results provide insight into the surface engineering of future Ti bone implants that are harmonized between the macrophage-governed early wound healing process and subsequent mesenchymal stem cell-centered osteogenesis function.

Bone integration capability of nanopolymorphic crystalline hydroxyapatite coated on titanium implants

OpenAIRE

Ogawa, Takahiro; Yamada,Masahiro; Ueno,; Tsukimura,Naoki; Ikeda,; Nakagawa,; Hori,; Suzuki,

2012-01-01

Masahiro Yamada*, Takeshi Ueno*, Naoki Tsukimura, Takayuki Ikeda, Kaori Nakagawa, Norio Hori, Takeo Suzuki, Takahiro OgawaLaboratory of Bone and Implant Sciences, The Weintraub Center for Reconstructive Biotechnology, Division of Advanced Prosthodontics, Biomaterials and Hospital Dentistry, UCLA School of Dentistry, Los Angeles, CA, USA *These authors contributed equally to this workAbstract: The mechanism by which hydroxyapatite (HA)-coated titanium promotes bone–implant integratio...

Surface modification of the titanium implant using TEA CO{sub 2} laser pulses in controllable gas atmospheres - Comparative study

Energy Technology Data Exchange (ETDEWEB)

Ciganovic, J.; Stasic, J.; Gakovic, B.; Momcilovic, M.; Milovanovic, D. [VINCA Institute of Nuclear Sciences, University of Belgrade, P.O. BOX 522, 11001 Belgrade (Serbia); Bokorov, M. [Faculty of Sciences, Department of Biology and Ecology, University of Novi Sad, Trg Dositeja Obradovica 3, 21000 Novi Sad (Serbia); Trtica, M., E-mail: etrtica@vinca.rs [VINCA Institute of Nuclear Sciences, University of Belgrade, P.O. BOX 522, 11001 Belgrade (Serbia)

2012-01-15

Interaction of a TEA CO{sub 2} laser, operating at 10.6 {mu}m wavelength and pulse duration of 100 ns (FWHM), with a titanium implant in various gas atmospheres was studied. The Ti implant surface modification was typically studied at the moderate laser beam energy density/fluence of 28 J/cm{sup 2} in the surrounding of air, N{sub 2}, O{sub 2} or He. The energy absorbed from the TEA CO{sub 2} laser beam is partially converted to thermal energy, which generates a series of effects, such as melting, vaporization of the molten material, shock waves, etc. The following titanium implant surface changes and phenomena were observed, depending on the gas used: (i) creation of cone-like surface structures in the atmospheres of air, N{sub 2} and O{sub 2}, and dominant micro-holes/pores in He ambient; (ii) hydrodynamic features, most prominent in air; (iii) formation of titanium nitride and titanium oxide layers, and (iv) occurrence of plasma in front of the implant. It can be concluded from this study that the reported laser fluence and gas ambiences can effectively be applied for enhancing the titanium implant roughness and creation of titanium oxides and nitrides on the strictly localized surface area. The appearance of plasma in front of the implants indicates relatively high temperatures created above the surface. This offers a sterilizing effect, facilitating contaminant-free conditions.

Carbon Fiber Biocompatibility for Implants

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Richard Petersen

2016-01-01

Full Text Available Carbon fibers have multiple potential advantages in developing high-strength biomaterials with a density close to bone for better stress transfer and electrical properties that enhance tissue formation. As a breakthrough example in biomaterials, a 1.5 mm diameter bisphenol-epoxy/carbon-fiber-reinforced composite rod was compared for two weeks in a rat tibia model with a similar 1.5 mm diameter titanium-6-4 alloy screw manufactured to retain bone implants. Results showed that carbon-fiber-reinforced composite stimulated osseointegration inside the tibia bone marrow measured as percent bone area (PBA to a great extent when compared to the titanium-6-4 alloy at statistically significant levels. PBA increased significantly with the carbon-fiber composite over the titanium-6-4 alloy for distances from the implant surfaces of 0.1 mm at 77.7% vs. 19.3% (p < 10−8 and 0.8 mm at 41.6% vs. 19.5% (p < 10−4, respectively. The review focuses on carbon fiber properties that increased PBA for enhanced implant osseointegration. Carbon fibers acting as polymer coated electrically conducting micro-biocircuits appear to provide a biocompatible semi-antioxidant property to remove damaging electron free radicals from the surrounding implant surface. Further, carbon fibers by removing excess electrons produced from the cellular mitochondrial electron transport chain during periods of hypoxia perhaps stimulate bone cell recruitment by free-radical chemotactic influences. In addition, well-studied bioorganic cell actin carbon fiber growth would appear to interface in close contact with the carbon-fiber-reinforced composite implant. Resulting subsequent actin carbon fiber/implant carbon fiber contacts then could help in discharging the electron biological overloads through electrochemical gradients to lower negative charges and lower concentration.

Poly-ε-caprolactone Coated and Functionalized Porous Titanium and Magnesium Implants for Enhancing Angiogenesis in Critically Sized Bone Defects

Directory of Open Access Journals (Sweden)

Laura Roland

2015-12-01

Full Text Available For healing of critically sized bone defects, biocompatible and angiogenesis supporting implants are favorable. Murine osteoblasts showed equal proliferation behavior on the polymers poly-ε-caprolactone (PCL and poly-(3-hydroxybutyrate/poly-(4-hydroxybutyrate (P(3HB/P(4HB. As vitality was significantly better for PCL, it was chosen as a suitable coating material for further experiments. Titanium implants with 600 µm pore size were evaluated and found to be a good implant material for bone, as primary osteoblasts showed a vitality and proliferation onto the implants comparable to well bottom (WB. Pure porous titanium implants and PCL coated porous titanium implants were compared using Live Cell Imaging (LCI with Green fluorescent protein (GFP-osteoblasts. Cell count and cell covered area did not differ between the implants after seven days. To improve ingrowth of blood vessels into porous implants, proangiogenic factors like Vascular Endothelial Growth Factor (VEGF and High Mobility Group Box 1 (HMGB1 were incorporated into PCL coated, porous titanium and magnesium implants. An angiogenesis assay was performed to establish an in vitro method for evaluating the impact of metallic implants on angiogenesis to reduce and refine animal experiments in future. Incorporated concentrations of proangiogenic factors were probably too low, as they did not lead to any effect. Magnesium implants did not yield evaluable results, as they led to pH increase and subsequent cell death.

Thin hydroxyapatite surface layers on titanium produced by ion implantation

CERN Document Server

Baumann, H; Bilger, G; Jones, D; Symietz, I

2002-01-01

In medicine metallic implants are widely used as hip replacement protheses or artificial teeth. The biocompatibility is in all cases the most important requirement. Hydroxyapatite (HAp) is frequently used as coating on metallic implants because of its high acceptance by the human body. In this paper a process is described by which a HAp surface layer is produced by ion implantation with a continuous transition to the bulk material. Calcium and phosphorus ions are successively implanted into titanium under different vacuum conditions by backfilling oxygen into the implantation chamber. Afterwards the implanted samples are thermally treated. The elemental composition inside the implanted region was determined by nuclear analysis methods as (alpha,alpha) backscattering and the resonant nuclear reaction sup 1 H( sup 1 sup 5 N,alpha gamma) sup 1 sup 2 C. The results of X-ray photoelectron spectroscopy indicate the formation of HAp. In addition a first biocompatibility test was performed to compare the growing of m...

Evaluation of torque loss value of MAD/MAM zirconia abutments with prefabricated titanium abutments

OpenAIRE

Marzieh Alikhasi; Roshanak Baghaie; Nasim khosronejad

2013-01-01

Background and Aims: In response to esthetic demand of patients, ceramic abutments have been developed. Despite esthetic of zirconia abutments, machining accuracy of these abutments has always been a question. Any misfit in the abutment-implant interface connection can lead to detorque and screw loosening. The aim of this study was to compare torque loss value of manually aided design/manually aided manufacture (MAD/MAM) zirconia abutments with prefabricated titanium abutments. Materials and ...

Characterizations of additive manufactured porous titanium implants.

Science.gov (United States)

Basalah, Ahmad; Shanjani, Yaser; Esmaeili, Shahrzad; Toyserkani, Ehsan

2012-10-01

This article describes physical, chemical, and mechanical characterizations of porous titanium implants made by an additive manufacturing method to gain insight into the correlation of process parameters and final physical properties of implants used in orthopedics. For the manufacturing chain, the powder metallurgy technology was combined with the additive manufacturing to fabricate the porous structure from the pure tanium powder. A 3D printing machine was employed in this study to produce porous bar samples. A number of physical parameters such as titanium powder size, polyvinyl alcohol (PVA) amount, sintering temperature and time were investigated to control the mechanical properties and porosity of the structures. The produced samples were characterized through porosity and shrinkage measurements, mechanical compression test and scanning electron microscopy (SEM). The results showed a level of porosity in the samples in the range of 31-43%, which is within the range of the porosity of the cancelluous bone and approaches the range of the porosity of the cortical bone. The results of the mechanical test showed that the compressive strength is in the wide range of 56-509 MPa implying the effect of the process parameters on the mechanical strengths. This technique of manufacturing of Ti porous structures demonstrated a low level of shrinkage with the shrinkage percentage ranging from 1.5 to 5%. Copyright © 2012 Wiley Periodicals, Inc.

Metallic artifact in MRI after removal of orthopedic implants

International Nuclear Information System (INIS)

Bagheri, Mohammad Hadi; Hosseini, Mehrdad Mohammad; Emami, Mohammad Jafar; Foroughi, Amin Aiboulhassani

2012-01-01

Objective: The aim of the present study was to evaluate the metallic artifacts in MRI of the orthopedic patients after removal of metallic implants. Subjects and methods: From March to August 2009, 40 orthopedic patients operated for removal of orthopedic metallic implants were studied by post-operative MRI from the site of removal of implants. A grading scale of 0–3 was assigned for artifact in MR images whereby 0 was considered no artifact; and I–III were considered mild, moderate, and severe metallic artifacts, respectively. These grading records were correlated with other variables including the type, size, number, and composition of metallic devices; and the site and duration of orthopedic devices stay in the body. Results: Metallic susceptibly artifacts were detected in MRI of 18 of 40 cases (45%). Screws and pins in removed hardware were the most important factors for causing artifacts in MRI. The artifacts were found more frequently in the patients who had more screws and pins in the removed implants. Gender, age, site of implantation of the device, length of the hardware, composition of the metallic implants (stainless steel versus titanium), and duration of implantation of the hardware exerted no effect in producing metallic artifacts after removal of implants. Short TE sequences of MRI (such as T1 weighted) showed fewer artifacts. Conclusion: Susceptibility of metallic artifacts is a frequent phenomenon in MRI of patients upon removal of metallic orthopedic implants.

Metallic artifact in MRI after removal of orthopedic implants.

Science.gov (United States)

Bagheri, Mohammad Hadi; Hosseini, Mehrdad Mohammad; Emami, Mohammad Jafar; Foroughi, Amin Aiboulhassani

2012-03-01

The aim of the present study was to evaluate the metallic artifacts in MRI of the orthopedic patients after removal of metallic implants. From March to August 2009, 40 orthopedic patients operated for removal of orthopedic metallic implants were studied by post-operative MRI from the site of removal of implants. A grading scale of 0-3 was assigned for artifact in MR images whereby 0 was considered no artifact; and I-III were considered mild, moderate, and severe metallic artifacts, respectively. These grading records were correlated with other variables including the type, size, number, and composition of metallic devices; and the site and duration of orthopedic devices stay in the body. Metallic susceptibly artifacts were detected in MRI of 18 of 40 cases (45%). Screws and pins in removed hardware were the most important factors for causing artifacts in MRI. The artifacts were found more frequently in the patients who had more screws and pins in the removed implants. Gender, age, site of implantation of the device, length of the hardware, composition of the metallic implants (stainless steel versus titanium), and duration of implantation of the hardware exerted no effect in producing metallic artifacts after removal of implants. Short TE sequences of MRI (such as T1 weighted) showed fewer artifacts. Susceptibility of metallic artifacts is a frequent phenomenon in MRI of patients upon removal of metallic orthopedic implants. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

Do screws and screw holes affect osteolysis in cementless cups using highly crosslinked polyethylene? A 7 to 10-year follow-up case-control study.

Science.gov (United States)

Taniguchi, N; Jinno, T; Takada, R; Koga, D; Ando, T; Okawa, A; Haro, H

2018-05-01

The use of screws and the presence of screw holes may cause acetabular osteolysis and implant loosening in cementless total hip arthroplasty (THA) using conventional polyethylene. In contrast, this issue is not fully understood using highly crosslinked polyethylene (HXLPE), particularly in large comparative study. Therefore, we performed a case-control study to assess the influence of screw usage and screw holes on: (1) implant fixation and osteolysis and (2) polyethylene steady-state wear rate, using cases with HXLPE liners followed up for 7-10 years postoperatively. The screw usage and screw holes adversely affect the implant fixation and incidence of wear-related osteolysis in THA with HXLPE. We reviewed 209 primary cementless THAs performed with 26-mm cobalt-chromium heads on HXLPE liners. To compare the effects of the use of screws and the presence of screw holes, the following groups were established: (1) with-screw (n=140); (2) without-screw (n=69); (3) no-hole (n=27) and (4) group in which a cup with screw holes, but no screw was used (n=42). Two adjunct groups (no-hole cups excluded) were established to compare the differences in the two types of HXLPE: (5) remelted group (n=100) and (6) annealed group (n=82). Implant stability and osteolysis were evaluated by plain radiography and computed tomography. The wear rate from 1 year to the final evaluation was measured using plain X-rays and PolyWare Digital software. All cups and stems achieved bony fixation. On CT-scan, no acetabular osteolysis was found, but there were 3 cases with a small area of femoral osteolysis. The mean steady-state wear rate of each group was (1) 0.031±0.022, (2) 0.033±0.035, (3) 0.031±0.024, (4) 0.029±0.018, (5) 0.030±0.018 and (6) 0.034±0.023mm/year, respectively. A comparison of the effects of screw usage or screw holes found no significant between-group differences in the implant stability, prevalence of osteolysis [no acetabular osteolysis and 3/209 at femoral side (1

Scaphoid Fracture Fixation with an Acutrak? Screw

OpenAIRE

Loving, Vilert A.; Richardson, Michael L.

2015-01-01

We report a case of fixation of a scaphoid fracture using an Acutrak? screw. This screw is cannulated and headless, which allows it to be implanted below the surface of the bone. It uses the same concept of variable thread pitch as the Herbert screw, but unlike the Herbert screw, is fully threaded, with continuously varying pitch along its length. This variable pitch creates constant compression across a fracture as the screw is advanced, and gives the screw its unique appearance. This featur...

New helical-shape magnetic pole design for Magnetic Lead Screw enabling structure simplification

DEFF Research Database (Denmark)

Lu, Kaiyuan; Xia, Yongming; Wu, Weimin

2015-01-01

Magnetic lead screw (MLS) is a new type of high performance linear actuator that is attractive for many potential applications. The main difficulty of the MLS technology lies in the manufacturing of its complicated helical-shape magnetic poles. Structure simplification is, therefore, quite...

Bloodcompatibility improvement of titanium oxide film modified by phosphorus ion implantation

International Nuclear Information System (INIS)

Yang, P.; Leng, Y.X.; Zhao, A.S.; Zhou, H.F.; Xu, L.X.; Hong, S.; Huang, N.

2006-01-01

Our recent investigation suggested that Ti-O thin film could be a newly developed antithrombotic material and its thromboresistance could be related to its physical properties of wide gap semiconductor. In this work, titanium oxide film was modified by phosphorus ion implantation and succeeding vacuum annealing. RBS were used to investigate phosphorus distribution profile. Contact angle test results show that phosphorus-doped titanium oxide film becomes more hydrophilic after higher temperature annealing, while its electric conductivity increases. Antithrombotic property of phosphorus-doped titanium oxide thin films was examined by clotting time and platelet adhesion tests. The results suggest that phosphorus doping is an effective way to improve the bloodcompatibility of titanium oxide film, and it is related to the changes of electron structure and surface properties caused by phosphorus doping

Influence of extruder screws speed and process temperature on the extrudate shape changes of the maize-spelt blends

Directory of Open Access Journals (Sweden)

Tomasz Żelaziński

2018-01-01

Full Text Available The objective of the study was examination of changes in the shape factors of extruded products, which occur as a result of different settings of the extrusion process variables. Samples analysed included products created by means of the extrusion process from a mixture of spelt flour and cornmeal, with the share of spelt at 70 to 100%. The samples were made with the use of a co-rotating twin screw extruder. Two speeds of extruder screw rotation (300 and 350 rpm as well as two levels of temperature (120 and 140°C were set during the investigation. The samples obtained were photographed in a light box, following which they underwent an image analysis with the use of specialist vision software. Four shape-related factors were determined: area, elongation factor, Heywood circularity factor and compactness factor. It was determined that the product shape changed significantly depending on the share of spelt flour in the mixture. Moreover, it was observed that change in the screw rotation speed within the analysed range may cause material changes in the shape of particular extrudates.

UV-activated 7-dehydrocholesterol-coated titanium implants promote differentiation of human umbilical cord mesenchymal stem cells into osteoblasts.

Science.gov (United States)

Satué, María; Ramis, Joana M; Monjo, Marta

2016-01-01

Vitamin D metabolites are essential for bone regeneration and mineral homeostasis. The vitamin D precursor 7-dehydrocholesterol can be used after UV irradiation to locally produce active vitamin D by osteoblastic cells. Furthermore, UV-irradiated 7-dehydrocholesterol is a biocompatible coating for titanium implants with positive effects on osteoblast differentiation. In this study, we examined the impact of titanium implants surfaces coated with UV-irradiated 7-dehydrocholesterol on the osteogenic differentiation of human umbilical cord mesenchymal stem cells. First, the synthesis of cholecalciferol (D3) was achieved through the incubation of the UV-activated 7-dehydrocholesterol coating for 48 h at 23℃. Further, we investigated in vitro the biocompatibility of this coating in human umbilical cord mesenchymal stem cells and its potential to enhance their differentiation towards the osteogenic lineage. Human umbilical cord mesenchymal stem cells cultured onto UV-irradiated 7-dehydrocholesterol-coated titanium implants surfaces, combined with osteogenic supplements, upregulated the gene expression of several osteogenic markers and showed higher alkaline phosphatase activity and calcein blue staining, suggesting increased mineralization. Thus, our results show that the use of UV irradiation on 7-dehydrocholesterol -treated titanium implants surfaces generates a bioactive coating that promotes the osteogenic differentiation of human umbilical cord mesenchymal stem cells, with regenerative potential for improving osseointegration in titanium-based bone anchored implants. © The Author(s) 2015.

Three-Dimensional Finite Element Analysis of the Stress Distribution at the Internal Implant-Abutment Connection.

Science.gov (United States)

Cho, Sung-Yong; Huh, Yoon-Hyuk; Park, Chan-Jin; Cho, Lee-Ra

2016-01-01

This study investigated stress distribution in four different implant-abutment interface conditions in the internal tapered connection implant system. Four different implant diameters (3.5 mm, 4.0 mm, 4.5 mm, and 5.0 mm) and two abutment types (hexagonal and conical) were simulated. Four unique implant-abutment interface conditions were assumed based on wall thickness, mating surface length, distance to the vertical stop, and abutment shape. Axial and oblique loading was applied during abutment screw preload, and the Von Mises stresses were measured at the implant-abutment and abutment-screw interfaces. The implant-abutment interface stress decreased as the wall thickness increased. As the mating surface increased, the stress distribution trended downward, and when the distance to the implant vertical stop was 0 μm, the Von Mises stress was extremely high at the vertical stop. Despite their different shapes, the abutments showed similar stress distributions. However, the maximum Von Mises stress was higher in the conical connection than in the hexagonal connection, particularly at the contralateral side to loading. To decrease the stress distribution at the implant-abutment interface, the implant wall thickness, mating surface contact length, distance to the vertical stop, and abutment shape should be carefully considered.

The belt-shaped screw-pinch reactor

International Nuclear Information System (INIS)

Bustraan, M.; Klippel, H.Th.; Veringa, H.J.; Verschuur, K.A.; Lievense, K.

1981-12-01

The belt-shaped screw pinch is a pulsed toroidal plasma with an elongated cross-section. Force-free currents in an outer plasma envelope of low density allow beta to rise to high values in the order of 50%. This is a potential possibility to develop an economically attractive reactor. The physical requirements of its realization are described: formation, heating and ignition of a very small amount of the fuel to be burnt in one pulse by the fields generated by normal or superconducting coils. Then follows injection of the greater part of the fuel by D-T pellets and consequent plasma heating and expansion by nuclear reactions without undue disturbing of the plasma current configuration. Technical requirements include an insulating first wall and fast rising magnetic fields produced by superconducting coils. This reactor system is compared with the tokamak and the reversed-field pinch system

Modular titanium alloy neck adapter failures in hip replacement - failure mode analysis and influence of implant material

Directory of Open Access Journals (Sweden)

Bloemer Wilhelm

2010-01-01

Full Text Available Abstract Background Modular neck adapters for hip arthroplasty stems allow the surgeon to modify CCD angle, offset and femoral anteversion intraoperatively. Fretting or crevice corrosion may lead to failure of such a modular device due to high loads or surface contamination inside the modular coupling. Unfortunately we have experienced such a failure of implants and now report our clinical experience with the failures in order to advance orthopaedic material research and joint replacement surgery. The failed neck adapters were implanted between August 2004 and November 2006 a total of about 5000 devices. After this period, the titanium neck adapters were replaced by adapters out of cobalt-chromium. Until the end of 2008 in total 1.4% (n = 68 of the implanted titanium alloy neck adapters failed with an average time of 2.0 years (0.7 to 4.0 years postoperatively. All, but one, patients were male, their average age being 57.4 years (36 to 75 years and the average weight 102.3 kg (75 to 130 kg. The failures of neck adapters were divided into 66% with small CCD of 130° and 60% with head lengths of L or larger. Assuming an average time to failure of 2.8 years, the cumulative failure rate was calculated with 2.4%. Methods A series of adapter failures of titanium alloy modular neck adapters in combination with a titanium alloy modular short hip stem was investigated. For patients having received this particular implant combination risk factors were identified which were associated with the occurence of implant failure. A Kaplan-Meier survival-failure-analysis was conducted. The retrieved implants were analysed using microscopic and chemical methods. Modes of failure were simulated in biomechanical tests. Comparative tests included modular neck adapters made of titanium alloy and cobalt chrome alloy material. Results Retrieval examinations and biomechanical simulation revealed that primary micromotions initiated fretting within the modular tapered neck

Immediate provisionalization of immediate implants in the esthetic zone: a prospective case series evaluating implant survival, esthetics, and bone maintenance.

Science.gov (United States)

Levin, Barry P; Wilk, Brian L

2013-05-01

This prospective study evaluates immediately placed and immediately provisionalized implants in the esthetic zone. All implants were TiO2-blasted, fluoride-modified, grade 4 titanium, with a coronal microthread design. Bone grafting and guided bone regeneration (GBR) was performed at all sites, and screw-retained temporary restorations were delivered on the day of surgery. All of the provisional crown(s) were out of occlusal function and remained in place for at least 8 weeks prior to initiation of definitive restorative therapy. Bone maintenance (BM) was considered successful if radiographs demonstrated proximal bone levels even or coronal to the implant platform. Of the 29 implants placed, 25 (86 percent) achieved bone maintenance at least 12 months post-loading with the final restorations. This study was considered successful, with 100 percent implant survival after at least 1 year loading of the final restoration, and 100 percent of patients were satisfied with the esthetics of their implant treatment.

Nanoscale characterization of bone-implant interface and biomechanical modulation of bone ingrowth

Energy Technology Data Exchange (ETDEWEB)

Clark, Paul A. [Tissue Engineering Laboratory MC 841, Departments of Anatomy and Cell Biology, Bioengineering, and Orthodontics, University of Illinois at Chicago, Chicago, 801 South Paulina Street, Illinois 60612 (United States)]. E-mail: pclark4@gmail.com; Clark, Andrew M. [Tissue Engineering Laboratory MC 841, Departments of Anatomy and Cell Biology, Bioengineering, and Orthodontics, University of Illinois at Chicago, Chicago, 801 South Paulina Street, Illinois 60612 (United States); Rodriguez, Anthony [Tissue Engineering Laboratory MC 841, Departments of Anatomy and Cell Biology, Bioengineering, and Orthodontics, University of Illinois at Chicago, Chicago, 801 South Paulina Street, Illinois 60612 (United States); Hussain, Mohammad A. [Tissue Engineering Laboratory MC 841, Departments of Anatomy and Cell Biology, Bioengineering, and Orthodontics, University of Illinois at Chicago, Chicago, 801 South Paulina Street, Illinois 60612 (United States); Mao, Jeremy J. [Tissue Engineering Laboratory MC 841, Departments of Anatomy and Cell Biology, Bioengineering, and Orthodontics, University of Illinois at Chicago, Chicago, 801 South Paulina Street, Illinois 60612 (United States)]. E-mail: jmao2@uic.edu

2007-04-15

Bone-implant interface is characterized by an array of cells and macromolecules. This study investigated the nanomechancial properties of bone-implant interface using atomic force microscopy in vitro, and the mechanical modulation of implant bone ingrowth in vivo using bone histomorphometry. Upon harvest of screw-type titanium implants placed in vivo in the rabbit maxilla and proximal femur for 4 weeks, nanoindentation was performed in the bone-implant interface at 60-{mu}m intervals radially from the implant surface. The average Young's Moduli (E) of the maxillary bone-implant interface was 1.13 {+-} 0.27 MPa, lacking significant differences at all intervals. In contrast, an increasing gradient of E was observed radially from the femur bone-implant interface: 0.87 {+-} 0.25 MPa to 2.24 {+-} 0.69 MPa, representing significant differences among several 60-{mu}m intervals. In a separate experiment, bone healing was allowed for 6 weeks for proximal femur implants. The right femoral implant received axial cyclic loading at 200 mN and 1 Hz for 10 min/d over 12 days, whereas the left femoral implant served as control. Cyclic loading induced significantly higher bone volume, osteoblast numbers per endocortical bone surface, mineral apposition rate, and bone formation rate than controls. These data demonstrate nanoscale and microscale characterizations of bone-implant interface, and mechanical modulation of bone ingrowth surrounding titanium implants.

Nanoscale characterization of bone-implant interface and biomechanical modulation of bone ingrowth

International Nuclear Information System (INIS)

Clark, Paul A.; Clark, Andrew M.; Rodriguez, Anthony; Hussain, Mohammad A.; Mao, Jeremy J.

2007-01-01

Bone-implant interface is characterized by an array of cells and macromolecules. This study investigated the nanomechancial properties of bone-implant interface using atomic force microscopy in vitro, and the mechanical modulation of implant bone ingrowth in vivo using bone histomorphometry. Upon harvest of screw-type titanium implants placed in vivo in the rabbit maxilla and proximal femur for 4 weeks, nanoindentation was performed in the bone-implant interface at 60-μm intervals radially from the implant surface. The average Young's Moduli (E) of the maxillary bone-implant interface was 1.13 ± 0.27 MPa, lacking significant differences at all intervals. In contrast, an increasing gradient of E was observed radially from the femur bone-implant interface: 0.87 ± 0.25 MPa to 2.24 ± 0.69 MPa, representing significant differences among several 60-μm intervals. In a separate experiment, bone healing was allowed for 6 weeks for proximal femur implants. The right femoral implant received axial cyclic loading at 200 mN and 1 Hz for 10 min/d over 12 days, whereas the left femoral implant served as control. Cyclic loading induced significantly higher bone volume, osteoblast numbers per endocortical bone surface, mineral apposition rate, and bone formation rate than controls. These data demonstrate nanoscale and microscale characterizations of bone-implant interface, and mechanical modulation of bone ingrowth surrounding titanium implants

Bisphenyl-Polymer/Carbon-Fiber-Reinforced Composite Compared to Titanium Alloy Bone Implant.

Science.gov (United States)

Petersen, Richard C

2011-05-03

Aerospace/aeronautical thermoset bisphenyl-polymer/carbon-fiber-reinforced composites are considered as new advanced materials to replace metal bone implants. In addition to well-recognized nonpolar chemistry with related bisphenol-polymer estrogenic factors, carbon-fiber-reinforced composites can offer densities and electrical conductivity/resistivity properties close to bone with strengths much higher than metals on a per-weight basis. In vivo bone-marrow tests with Sprague-Dawley rats revealed far-reaching significant osseoconductivity increases from bisphenyl-polymer/carbon-fiber composites when compared to state-of-the-art titanium-6-4 alloy controls. Midtibial percent bone area measured from the implant surface increased when comparing the titanium alloy to the polymer composite from 10.5% to 41.6% at 0.8 mm, P engineering potential.

Mathematical filtering minimizes metallic halation of titanium implants in MicroCT images.

Science.gov (United States)

Ha, Jee; Osher, Stanley J; Nishimura, Ichiro

2013-01-01

Microcomputed tomography (MicroCT) images containing titanium implant suffer from x-rays scattering, artifact and the implant surface is critically affected by metallic halation. To improve the metallic halation artifact, a nonlinear Total Variation denoising algorithm such as Split Bregman algorithm was applied to the digital data set of MicroCT images. This study demonstrated that the use of a mathematical filter could successfully reduce metallic halation, facilitating the osseointegration evaluation at the bone implant interface in the reconstructed images.

CNC-milled titanium frameworks supported by implants in the edentulous jaw: a 10-year comparative clinical study.

Science.gov (United States)

Örtorp, Anders; Jemt, Torsten

2012-03-01

No long-term clinical studies covering more than 5 years are available on Computer Numeric Controlled (CNC) milled titanium frameworks. To evaluate and compare the clinical and radiographic performance of implant-supported prostheses provided with CNC titanium frameworks in the edentulous jaw with prostheses with cast gold-alloy frameworks during the first 10 years of function. Altogether, 126 edentulous patients were by random provided with 67 prostheses with titanium frameworks (test) in 23 maxillas and 44 mandibles, and with 62 prostheses with gold-alloy castings (control) in 31 maxillas and 31 mandibles. Clinical and radiographic 10-year data were collected for the groups and statistically compared on patient level. The 10-year prosthesis and implant cumulative survival rate was 95.6% compared with 98.3%, and 95.0% compared with 97.9% for test and control groups, respectively (p > .05). No implants were lost after 5 years of follow-up. Smokers lost more implants than nonsmokers after 5 years of follow-up (p .05), respectively. One prosthesis was lost in each group due to loss of implants, and one prosthesis failed due to framework fracture in the test group. Two metal fractures were registered in each group. More appointments of maintenance were needed for the prostheses in the maxilla compared with those in the mandible (p CNC-milled titanium frameworks are a viable alternative to gold-alloy castings for restoring patients with implant-supported prostheses in the edentulous jaw. © 2009 Wiley Periodicals, Inc.

[Long-term follow-up study of titanium implant impact on pediatric mandibular growth and development].

Science.gov (United States)

Hu, Yun; Li, Wei; Chen, Qi; Song, Fumin; Tang, Wei; Wang, Hang

2015-08-01

To explore the impact of titanium implant on the growth and development of pediatric mandible after suffering from mandibular fracture and undergoing open reduction and internal fixation (ORIF) compared with those that underwent titanium plate removal postoperatively. Fifteen pediatric patients with mandibular fracture who underwent ORIF were included in this study. Eight patients did not undergo titanium implant removal postoperatively, whereas the other seven patients underwent the routine. The postoperative data of the pediatrics were collected for comparative analysis by taking the patients' frontal and lateral photos, recording the inter-incisor distance, and measuring the height of mandibular ramus, length of the mandibular body, and combined length of the mandible in three-dimensional reconstruction image. All patients had acceptable facial contour, mouth opening, and occlusion, without obvious abnormalities. The radiography showed no significant difference between the bilateral mandibular lengths in the two groups of patients (P>0.05). The titanium plants have no significant impact on the growth and development of pediatric mandible postoperatively; hence, the question on whether the titanium plates should be removed or not may be neglected. The removal operation may lead to secondary trauma; thus, performing titanium plate removal routinely is not recommended.

Near-Net Shape Fabrication Using Low-Cost Titanium Alloy Powders

Energy Technology Data Exchange (ETDEWEB)

Dr. David M. Bowden; Dr. William H. Peter

2012-03-31

The use of titanium in commercial aircraft production has risen steadily over the last half century. The aerospace industry currently accounts for 58% of the domestic titanium market. The Kroll process, which has been used for over 50 years to produce titanium metal from its mineral form, consumes large quantities of energy. And, methods used to convert the titanium sponge output of the Kroll process into useful mill products also require significant energy resources. These traditional approaches result in product forms that are very expensive, have long lead times of up to a year or more, and require costly operations to fabricate finished parts. Given the increasing role of titanium in commercial aircraft, new titanium technologies are needed to create a more sustainable manufacturing strategy that consumes less energy, requires less material, and significantly reduces material and fabrication costs. A number of emerging processes are under development which could lead to a breakthrough in extraction technology. Several of these processes produce titanium alloy powder as a product. The availability of low-cost titanium powders may in turn enable a more efficient approach to the manufacture of titanium components using powder metallurgical processing. The objective of this project was to define energy-efficient strategies for manufacturing large-scale titanium structures using these low-cost powders as the starting material. Strategies include approaches to powder consolidation to achieve fully dense mill products, and joining technologies such as friction and laser welding to combine those mill products into near net shape (NNS) preforms for machining. The near net shape approach reduces material and machining requirements providing for improved affordability of titanium structures. Energy and cost modeling was used to define those approaches that offer the largest energy savings together with the economic benefits needed to drive implementation. Technical

Guided tissue regeneration ensures osseointegration of dental implants placed into extraction sockets. An experimental study in monkeys

DEFF Research Database (Denmark)

Warrer, L; Gotfredsen, K; Hjørting-Hansen, E

1991-01-01

on the buccal and palatal aspects of the maxillary molars in both sides of the jaw. The second molars were then extracted and self tapping titanium implants of the screw type (Astra Dental Implants) were inserted into the sockets of the largest roots. In the coronal portion of the sockets, a void was always...... present between the implant and the socket walls. In one side of the jaw, a membrane (Gore-Tex Augmentation Material) was adjusted to cover the implant. The implant in the other side of the jaw served as control and was only covered by the tissue flaps. Microscopic analysis after 3 months of healing...... technique can secure complete osseointegration of implants inserted immediately into extraction sockets....

[Complex skull defects reconstruction with САD/САМ titanium and polyetheretherketone (PEEK) implants].