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Bone Tissue Response (bone + tissue_response)
Selected AbstractsBone Tissue Responses to Surface-Modified Zirconia Implants: A Histomorphometric and Removal Torque Study in the RabbitCLINICAL IMPLANT DENTISTRY AND RELATED RESEARCH, Issue 2005Lars Sennerby DDS ABSTRACT Background: Zirconia ceramics are biocompatible and have mechanical properties that make them suitable as materials for dental implants. Little is known about how surface modification influences the stability and bone tissue response to zirconia implants. Purpose: The objective of the investigation was to histologically and biomechanically evaluate the bone tissue response to zirconia implants with two different surface modifications in comparison with machined, nonmodified zirconia implants and oxidized titanium implants. Materials and Methods: Threaded zirconia implants with a diameter of 3.75 mm with either a machined surface (Zr-Ctr) or one of two surface modifications (Zr-A and Zr-B) were manufactured. Oxidized titanium (Ti-Ox) implants 3.75 mm in diameter were also used. The implants were characterized with regard to surface topography using an interferometer. Twelve rabbits received 96 implants using a rotational scheme, two in each tibia and two in each femur. The implants in six rabbits were subjected to removal torque (RTQ) tests after a healing period of 6 weeks. The implants in the remaining six animals were removed en bloc for light microscopic analysis. Back-scatter scanning electron microscopic (BS-SEM) analyses were used to evaluate the state of the bone-implant interface at the modified zirconia implants after RTQ testing. Results: The Ti-Ox and Zr-A implants showed the highest surface roughness, followed by the Zr-B implants and, finally, the Zr-Ctr implants. The nonmodified ZrO2 implants showed statistically significant lower RTQs than all other implants. No significant differences in bone-implant contact or bone area filling the threads were observed. BS-SEM showed intact surface layers of the surface-modified implants after RTQ testing and revealed fracture of the interface bone rather than a separation. Conclusion: The present study showed a strong bone tissue response to surface-modified zirconia implants after 6 weeks of healing in rabbit bone. The modified zirconia implants showed a resistance to torque forces similar to that of oxidized implants and a four- to fivefold increase compared with machined zirconia implants. The findings suggest that surface-modified zirconia implants can reach firm stability in bone. [source] Bone tissue responses to glass fiber-reinforced composite implants , a histomorphometric studyCLINICAL ORAL IMPLANTS RESEARCH, Issue 6 2009A. M. Ballo Abstract Objectives: The aims of this study were to evaluate bone-to-implant contact (BIC) and the osteoconductive capacity of bioactive fiber-reinforced composite implant (FRC) in vivo. Material and methods: Threaded sand-blasted FRC implants and threaded FRC implants with bioactive glass (BAG) were fabricated for the study. Titanium implants were used as a reference. Eighteen implants (diameter 4.1 mm, length 10 mm) were implanted in the tibia of six pigs using the press-fit technique. The animals were sacrificed after 4 and 12 weeks. Histomorphometric and scanning electron microscopic (SEM) analyses were performed to characterize BIC. Results: In general, the highest values of BIC were measured in FRC-BAG implants, followed by FRC and Ti implants. At 4 weeks, the BIC was 33% for threaded FRC-BAG, 27% for FRC and 19% for Ti. At 12 weeks, BIC was 47% for threaded FRC-BAG, 40% for FRC and 42% for Ti. Four weeks after implantation, all the implants appeared biologically fixed by a newly formed woven bone arranged in the thin bone trabeculae filling the gap between the implant and the bone of the recipient site. Twelve weeks after implantation, the thickness of the woven bone trabeculae had increased, especially around the FRC-BAG implants. Conclusion: Our results suggest that the FRC implant is biocompatible in bone. The biological behavior of FRC was comparable to that of Ti after 4 and 12 weeks of implantation. Furthermore, the addition of BAG to the FRC implant increased peri-implant osteogenesis and bone maturation. [source] Porous TiNi Biomaterial by Self-Propagating High-Temperature Synthesis,ADVANCED ENGINEERING MATERIALS, Issue 6 2004J.S. Kim Abstract Porous TiNi shape-memory alloy (TiNi SMA) bodies with controlled pore structure were produced from the (Ti+Ni) powder mixture by self-propagating high-temperature synthesis (SHS) method. The effect of processing variables such as the kind of starting powders, ignition temperature and preheating schedule on the behavior of combustion wave propagation, the formation of phases and pore structure was investigated. The relationship between pore structure and mechanical properties was also investigated. An in vivo test was performed to evaluate bone tissue response and histocompatibility of porous TiNi SMA using 15 New Zealand white rabbits. No apparent adverse reactions such as inflammation and foreign body reaction were noted on or around all implanted porous TiNi SMA blocks. Bone ingrowth was found in the pore space of all implanted blocks. [source] Tissue response to polyglycolide, polydioxanone, polylevolactide, and metallic pins in cancellous bone: An experimental study on rabbitsJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 8 2006Harri Pihlajamäki Abstract The purpose of this study was to investigate, qualitatively and histoquantitatively, the tissue response of rabbit femur cancellous bone to polyglycolide (PGA), polydioxanone (PDS), polylevolactide (PLLA), and stainless steel pins under identical conditions. Eighty knees in 50 rabbits were operated on by inserting bioabsorbable pins (PGA, PDS, or PLLA) together with metallic Kirschner wire in 60, and two metallic Kirschner wires alone in 20 knees, while 20 knees served as intact controls. Follow-up times were 3, 6, 12, 24, and 52 weeks. Cancellous bone tissue response to implants was studied using histological, histomorphometrical, microradiographical, and oxytetracycline fluorescence methods. Residual fragments of PGA and PDS were seen at 24 weeks. Complete degradation of these polymers had taken place before 52 weeks. No signs of degradation of the PLLA pins were observed within the entire follow-up period. The osteoid formation surfaces at tissue implant-interface were statistically larger in all test groups as compared to intact controls. The number of macrophages at tissue implant-interfaces increased in all bioabsorbable implant specimens until 6 weeks, and with PGA until 12 weeks. No differences in the osseous response emerged when comparing groups of bioabsorbable implants with each other or with stainless steel group. Bioabsorbable pins and metallic Kirschner wires evoked an osteoconductive response in the cancellous bone surrounding implant, but the response intensity between implants displayed no differences. This suggests a simple, nonspecific walling-off new-bone front type of response. Consequently, the polymers possessed no specific osteostimulatory or osteoinhibitory properties. Within the follow-up, no significant differences in biocompatibility between the implants appeared, and no frank inflammatory foreign-body reactions occurred. The small-volume pins obviously did not exceed the local tissue tolerance and clearing capacity of the bone. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 24:1597,1606, 2006 [source] Bone Reformation and Implant Integration following Maxillary Sinus Membrane Elevation: An Experimental Study in PrimatesCLINICAL IMPLANT DENTISTRY AND RELATED RESEARCH, Issue 1 2006Vinicius C Palma DDS ABSTRACT Background:, Recent clinical studies have described maxillary sinus floor augmentation by simply elevating the maxillary sinus membrane without the use of adjunctive grafting materials. Purpose:, This experimental study aimed at comparing the histologic outcomes of sinus membrane elevation and simultaneous placement of implants with and without adjunctive autogenous bone grafts. The purpose was also to investigate the role played by the implant surface in osseointegration under such circumstances. Materials and Methods:, Four tufted capuchin primates had all upper premolars and the first molar extracted bilaterally. Four months later, the animals underwent maxillary sinus membrane elevation surgery using a replaceable bone window technique. The schneiderian membrane was kept elevated by insertion of two implants (turned and oxidized, Brånemark System®, Nobel Biocare AB, Göteborg, Sweden) in both sinuses. The right sinus was left with no additional treatment, whereas the left sinus was filled with autogenous bone graft. Implant stability was assessed through resonance frequency analysis (OsstellTM, Integration Diagnostics AB, Göteborg, Sweden) at installation and at sacrifice. The pattern of bone formation in the experimental sites and related to the different implant surfaces was investigated using fluorochromes. The animals were sacrificed 6 months after the maxillary sinus floor augmentation procedure for histology and histomorphometry (bone-implant contact, bone area in threads, and bone area in rectangle). Results:, The results showed no differences between membrane-elevated and grafted sites regarding implant stability, bone-implant contacts, and bone area within and outside implant threads. The oxidized implants exhibited improved integration compared with turned ones as higher values of bone-implant contact and bone area within threads were observed. Conclusions:, The amount of augmented bone tissue in the maxillary sinus after sinus membrane elevation with or without adjunctive autogenous bone grafts does not differ after 6 months of healing. New bone is frequently deposited in contact with the schneiderian membrane in coagulum-alone sites, indicating the osteoinductive potential of the membrane. Oxidized implants show a stronger bone tissue response than turned implants in sinus floor augmentation procedures. [source] Bone Tissue Responses to Surface-Modified Zirconia Implants: A Histomorphometric and Removal Torque Study in the RabbitCLINICAL IMPLANT DENTISTRY AND RELATED RESEARCH, Issue 2005Lars Sennerby DDS ABSTRACT Background: Zirconia ceramics are biocompatible and have mechanical properties that make them suitable as materials for dental implants. Little is known about how surface modification influences the stability and bone tissue response to zirconia implants. Purpose: The objective of the investigation was to histologically and biomechanically evaluate the bone tissue response to zirconia implants with two different surface modifications in comparison with machined, nonmodified zirconia implants and oxidized titanium implants. Materials and Methods: Threaded zirconia implants with a diameter of 3.75 mm with either a machined surface (Zr-Ctr) or one of two surface modifications (Zr-A and Zr-B) were manufactured. Oxidized titanium (Ti-Ox) implants 3.75 mm in diameter were also used. The implants were characterized with regard to surface topography using an interferometer. Twelve rabbits received 96 implants using a rotational scheme, two in each tibia and two in each femur. The implants in six rabbits were subjected to removal torque (RTQ) tests after a healing period of 6 weeks. The implants in the remaining six animals were removed en bloc for light microscopic analysis. Back-scatter scanning electron microscopic (BS-SEM) analyses were used to evaluate the state of the bone-implant interface at the modified zirconia implants after RTQ testing. Results: The Ti-Ox and Zr-A implants showed the highest surface roughness, followed by the Zr-B implants and, finally, the Zr-Ctr implants. The nonmodified ZrO2 implants showed statistically significant lower RTQs than all other implants. No significant differences in bone-implant contact or bone area filling the threads were observed. BS-SEM showed intact surface layers of the surface-modified implants after RTQ testing and revealed fracture of the interface bone rather than a separation. Conclusion: The present study showed a strong bone tissue response to surface-modified zirconia implants after 6 weeks of healing in rabbit bone. The modified zirconia implants showed a resistance to torque forces similar to that of oxidized implants and a four- to fivefold increase compared with machined zirconia implants. The findings suggest that surface-modified zirconia implants can reach firm stability in bone. [source] Bone Formation at Titanium Implants Prepared with Iso- and Anisotropic Surfaces of Similar Roughness: An in Vivo StudyCLINICAL IMPLANT DENTISTRY AND RELATED RESEARCH, Issue 1 2005Anna Göransson DDS ABSTRACT Background: Implant surface topography influences the bone response after implantation. However, the importance of surface orientation is not known. Purpose: The aim of this study was to investigate the bone tissue response and the stability of titanium implants prepared with isotropic and anisotropic surfaces of similar roughness. Materials and Methods: A total of 18 implants were divided into two groups and were inserted into the femurs of nine rabbits for 12 weeks. Confocal laser scanning microscopy was used for the topographic description to verify that the two different surfaces were modified as intended. The stability of the implants was recorded by resonance frequency (RF) measurements at insertion and at time of removal, after which the implants were evaluated histomorphometrically. Results: RF measurements showed that implant stability increased with time. However, there was no significant difference between the two different surface modifications at insertion and after 12 weeks. The histomorphometric comparison revealed no statistically significant differences in regard to either bone-to-metal contact or bone area inside the threads. Conclusion: Titanium implants prepared with isotropic and anisotropic surfaces of similar roughness integrate similarly to bone during the 3 months after implantation. [source] Histologic Analysis of Clinical Biopsies Taken 6 Months and 3 Years after Maxillary Sinus Floor Augmentation with 80% Bovine Hydroxyapatite and 20% Autogenous Bone Mixed with Fibrin GlueCLINICAL IMPLANT DENTISTRY AND RELATED RESEARCH, Issue 2 2001Mats Hallman DDS Abstract: Background: Bovine hydroxyapatite (Bio-Oss®, Geistlich Pharmaceutical, Wollhausen, Switzerland) has been suggested to be used in maxillary sinus floor augmentation procedures prior to or in conjunction with implant placement. However, the long-term histologic fate of this material is not well understood. Purpose: The aim with this study was to histologically evaluate the tissue response in patients to a mixture of bovine hydroxyapatite (BH), autogenous bone, and fibrin glue 6 months and 3 years after a maxillary sinus floor augmentation procedure. Materials and Method: Biopsies were taken from a group of 20 consecutive patients 6 months (n = 16) and 3 years (n = 12) after maxillary sinus floor augmentation with a mixture of BH (80%), autogenous bone (20%), and fibrin glue and prepared for histologic analysis. Results: Light microscopy and morphometry from biopsies taken after 6 months showed various amounts of mineralized bone tissue. The specimen area was occupied by 54.1 ± 12.6% nonmineralized tissue, followed by 21.2 ± 24.5% lamellar bone, 14.5 ± 10.3% BH particles, and 10.2 ± 13.4% woven bone. The nonmineralized tissue seen in bone-forming areas consisted of a loose connective tissue, rich with vessels and cells. There were no signs of resorption of the BH particles. The lamellar bone appeared to have originated from the recipient site and was seldom in contact with the BH particles. After 3 years, the nonmineralized tissue area had decreased to 36.0 ± 19.0% (p > .05) and consisted mainly of bone marrow tissue. The surface area of lamellar bone had increased to 50.7 ± 22.8% (p > .05), and there was almost no immature bone. The mean specimen area occupied by BH particles, was 12.4 ± 8.7% and had not changed from 6 months (not significant). Moreover, the sizes of the particles were similar after 6 months and 3 years. The degree of BH particle,bone contact had increased from 28.8%± 19.9% after 6 months to 54.5 ± 28.8% after 3 years (p > .05). Conclusion: Histology of specimens from maxillary sinuses augmented with 80% BH particles, 20% autogenous bone, and fibrin glue showed a positive bone tissue response after 6 months and 3 years after augmentation of the maxillary sinus floor prior to implant placement in a group fo 20 patients. The bone surrounding and in contact with the BH particles after 6 months was mainly immature woven bone, which with time was replaced by mature lamellar bone filling the interparticle space as observed in the 3-year specimens. Moreover, bone-integrated BH particles seem to be resistant to resorption. The results indicate that the procedure may be considered when only small amounts of intraoral autogenous bone graft are available. [source] | ||||||||||