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Guillaume Haiat - One of the best experts on this subject based on the ideXlab platform.
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stress shielding at the bone Implant interface influence of surface roughness and of the bone Implant Contact ratio
Journal of Orthopaedic Research, 2020Co-Authors: Maria Letizia Raffa, Vuhieu Nguyen, Philippe Hernigou, Charleshenri Flouzatlachaniette, Guillaume HaiatAbstract:Short and long-term stabilities of cementless Implants are strongly determined by the interfacial load transfer between Implants and bone tissue. Stress-shielding effects arise from shear stresses due to the difference of material properties between bone and the Implant. It remains difficult to measure the stress field in periprosthetic bone tissue. This study proposes to investigate the dependence of the stress field in periprosthetic bone tissue on i) the Implant surface roughness, ii) material properties of bone and of the Implant, iii) the bone-Implant Contact ratio. To do so, a microscale 2-D finite element model of an osseointegrated bone-Implant interface was developed where the surface roughness was modeled by a sinusoidal surface. The results show that the isostatic pressure is not affected by the presence of the bone-Implant interface while shear stresses arise due to the combined effects of a geometrical singularity (for low surface roughness) and of shear stresses at the bone-Implant interface (for high surface roughness). Stress-shielding effects are likely to be more important when the bone-Implant Contact ratio value is low, which corresponds to a case of relatively low Implant stability. Shear stress reach a maximum value at a distance from the interface comprised between 0 and 0.1 time roughness wavelength λ and tend to 0 at a distance from the Implant surface higher than λ, independently from bone-Implant Contact ratio and waviness ratio. A comparison with an analytical model allows validating the numerical results. Future work should use the present approach to model osseointegration phenomena. This article is protected by copyright. All rights reserved.
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stress shielding at the bone Implant interface influence of surface roughness and of the bone Implant Contact ratio
Journal of Orthopaedic Research, 2020Co-Authors: Maria Letizia Raffa, Vuhieu Nguyen, Philippe Hernigou, Charleshenri Flouzatlachaniette, Guillaume HaiatAbstract:Short and long-term stabilities of cementless Implants are strongly determined by the interfacial load transfer between Implants and bone tissue. Stress-shielding effects arise from shear stresses due to the difference of material properties between bone and the Implant. It remains difficult to measure the stress field in periprosthetic bone tissue. This study proposes to investigate the dependence of the stress field in periprosthetic bone tissue on (i) the Implant surface roughness, (ii) the material properties of bone and of the Implant, (iii) the bone-Implant Contact ratio. To do so, a microscale two-dimensional finite element model of an osseointegrated bone-Implant interface was developed where the surface roughness was modeled by a sinusoidal surface. The results show that the isostatic pressure is not affected by the presence of the bone-Implant interface while shear stresses arise due to the combined effects of a geometrical singularity (for low surface roughness) and of shear stresses at the bone-Implant interface (for high surface roughness). Stress-shielding effects are likely to be more important when the bone-Implant Contact ratio value is low, which corresponds to a case of relatively low Implant stability. Shear stress reach a maximum value at a distance from the interface comprised between 0 and 0.1 time roughness wavelength λ and tend to 0 at a distance from the Implant surface higher than λ, independently from bone-Implant Contact ratio and waviness ratio. A comparison with an analytical model allows validating the numerical results. Future work should use the present approach to model osseointegration phenomena.
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Stress shielding at the bone‐Implant interface: influence of surface roughness and of the bone‐Implant Contact ratio
Journal of Orthopaedic Research, 2020Co-Authors: Maria Letizia Raffa, Vuhieu Nguyen, Philippe Hernigou, Charles-henri Flouzat- Lachaniette, Guillaume HaiatAbstract:Short and long-term stabilities of cementless Implants are strongly determined by the interfacial load transfer between Implants and bone tissue. Stress-shielding effects arise from shear stresses due to the difference of material properties between bone and the Implant. It remains difficult to measure the stress field in periprosthetic bone tissue. This study proposes to investigate the dependence of the stress field in periprosthetic bone tissue on i) the Implant surface roughness, ii) material properties of bone and of the Implant, iii) the bone-Implant Contact ratio. To do so, a microscale 2-D finite element model of an osseointegrated boneImplant interface was developed where the surface roughness was modeled by a sinusoidal surface. The results show that the isostatic pressure is not affected by the presence of the bone-Implant interface while shear stresses arise due to the combined effects of a geometrical singularity (for low surface roughness) and of shear stresses at the bone-Implant interface (for high surface roughness). Stress-shielding effects are likely to be more important when the bone-Implant Contact ratio value is low, which corresponds to a case of relatively low Implant stability. Shear stress reach a maximum value at a distance from the interface comprised between 0 and 0.1 time roughness wavelength λ and tend to 0 at a distance from the Implant surface higher than λ, independently from bone-Implant Contact ratio and waviness ratio. A comparison with an analytical model allows validating the numerical results. Future work should use the present approach to model osseointegration phenomena.
Palle Holmstrup - One of the best experts on this subject based on the ideXlab platform.
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bone to Implant Contact after maxillary sinus floor augmentation with bio oss and autogenous bone in different ratios in mini pigs
Clinical Oral Implants Research, 2013Co-Authors: Thomas Jense, Sore Schou, Hans Jorge G Gunderse, Julie Lyng Forma, Hendrik Terheyde, Palle HolmstrupAbstract:Objectives The objective was to test the hypotheses: (i) no differences in bone-to-Implant Contact formation, and (ii) no differences between the use of autogenous mandibular or iliac bone grafts, when autogenous bone, Bio-Oss mixed with autogenous bone, or Bio-Oss is used as graft for the maxillary sinus floor augmentation. Material and methods Bilateral sinus floor augmentation was performed in 40 mini pigs with: (A) 100% autogenous bone, (B) 75% autogenous bone and 25% Bio-Oss, (C) 50% autogenous bone and 50% Bio-Oss, (D) 25% autogenous bone and 75% Bio-Oss, or (E) 100% Bio-Oss. Autogenous bone was harvested from the iliac crest or the mandible and the graft composition was selected at random and placed concomitant with the Implant placement. The animals were euthanized 12 weeks after surgery. Bone-to-Implant Contact was estimated by stereological methods and summarized as median percentage with 95% confidence interval (CI). Bone-to-Implant Contact formation was evaluated by fluorochrome labelling and assessed by median odds ratios (OR) with 95% (CI). Results Median bone-to-Implant Contact was: (A) 42.9% (95% CI: 32.1–54.5%), (B) 37.8% (95% CI: 27.1–49.9%), (C) 43.9% (95% CI: 32.6–55.9%), (D) 30.2% (95% CI: 21.6–40.3%), and (E) 13.9% (95% CI: 11.4–16.9%). Bone-to-Implant Contact was significantly higher for A, B, C, D as compared to E (P < 0.0001). Bone-to-Implant Contact was not significantly influenced by the ratio of Bio-Oss and autogenous bone (P = 0.19) or the origin of the autogenous bone (P = 0.72). Fluorochrome labelling revealed extensive variation in bone-to-Implant Contact formation over time. The labelling at weeks 2–3 was significantly increased with A compared to E (OR = 8.1 CI: 5.0–13.1, P < 0.0001), whereas E showed a significantly increased labelling at weeks 8–9 compared to A (OR = 0.5 CI: 0.3–0.7, P = 0.0028). Conclusions The hypothesis of no differences in bone-to-Implant Contact between the various treatment modalities was rejected since the bone-to-Implant Contact was significantly increased with autogenous bone or Bio-Oss mixed with autogenous bone as compared to Bio-Oss. Early bone-to-Implant Contact formation was more advanced with autogenous bone. No differences between the use of mandibular or iliac bone grafts were observed since the bone-to-Implant Contact was not significantly influenced by the origin of the bone graft.
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Bone-to-Implant Contact after maxillary sinus floor augmentation with Bio-Oss and autogenous bone in different ratios in mini pigs
Clinical oral implants research, 2012Co-Authors: Thomas Jensen, Søren Schou, Hans Jørgen G. Gundersen, Julie Lyng Forman, Hendrik Terheyden, Palle HolmstrupAbstract:Objectives The objective was to test the hypotheses: (i) no differences in bone-to-Implant Contact formation, and (ii) no differences between the use of autogenous mandibular or iliac bone grafts, when autogenous bone, Bio-Oss mixed with autogenous bone, or Bio-Oss is used as graft for the maxillary sinus floor augmentation. Material and methods Bilateral sinus floor augmentation was performed in 40 mini pigs with: (A) 100% autogenous bone, (B) 75% autogenous bone and 25% Bio-Oss, (C) 50% autogenous bone and 50% Bio-Oss, (D) 25% autogenous bone and 75% Bio-Oss, or (E) 100% Bio-Oss. Autogenous bone was harvested from the iliac crest or the mandible and the graft composition was selected at random and placed concomitant with the Implant placement. The animals were euthanized 12 weeks after surgery. Bone-to-Implant Contact was estimated by stereological methods and summarized as median percentage with 95% confidence interval (CI). Bone-to-Implant Contact formation was evaluated by fluorochrome labelling and assessed by median odds ratios (OR) with 95% (CI). Results Median bone-to-Implant Contact was: (A) 42.9% (95% CI: 32.1–54.5%), (B) 37.8% (95% CI: 27.1–49.9%), (C) 43.9% (95% CI: 32.6–55.9%), (D) 30.2% (95% CI: 21.6–40.3%), and (E) 13.9% (95% CI: 11.4–16.9%). Bone-to-Implant Contact was significantly higher for A, B, C, D as compared to E (P
Brigitte Grosgogeat - One of the best experts on this subject based on the ideXlab platform.
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In Vivo Evaluation of Immediately Loaded Stainless Steel and Titanium Orthodontic Screws in a Growing Bone
PLoS ONE, 2013Co-Authors: Kerstin Gritsch, Norbert Laroche, Jeanne-marie Bonnet, Patrick Exbrayat, Laurent Morgon, Muriel Rabilloud, Brigitte GrosgogeatAbstract: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.
Adriano Piattelli - One of the best experts on this subject based on the ideXlab platform.
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the effect of undersizing and tapping on bone to Implant Contact and Implant primary stability a histomorphometric study on bovine ribs
The Journal of Advanced Prosthodontics, 2018Co-Authors: Danilo Alessio Di Stefano, Adriano Piattelli, Vittoria Perrotti, Gian Battista Greco, Claudia Cappucci, Paolo Arosio, Giovanna IezziAbstract:PURPOSE Implant site preparation may be adjusted to achieve the maximum possible primary stability. The aim of this investigation was to study the relation among bone-to-Implant Contact at insertion, bone density, and Implant primary stability intra-operatively measured by a torque-measuring Implant motor, when Implant sites were undersized or tapped. MATERIALS AND METHODS Undersized (n=14), standard (n=13), and tapped (n=13) Implant sites were prepared on 9 segments of bovine ribs. After measuring bone density using the Implant motor, 40 Implants were placed, and their primary stability assessed by measuring the integral of the torque-depth insertion curve. Bovine ribs were then processed histologically, the bone-to-Implant Contact measured and statistically correlated to bone density and the integral. RESULTS Bone-to-Implant Contact and the integral of the torque-depth curve were significantly greater for undersized sites than tapped sites. Moreover, a correlation between bone to Implant Contact, the integral and bone density was found under all preparation conditions. The slope of the bone-to-Implant/density and integral/density lines was significantly greater for undersized sites, while those corresponding to standard prepared and tapped sites did not differ significantly. CONCLUSION The integral of the torque-depth curve provided reliable information about bone-to-Implant Contact and primary Implant stability even in tapped or undersized sites. The linear relations found among the parameters suggests a connection between extent and modality of undersizing and the corresponding increase of the integral and, consequently, of primary stability. These results might help the physician determine the extent of undersizing needed to achieve the proper Implant primary stability, according to the planned loading protocol.
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Bone-Implant Contact around Crestal and Subcrestal Dental Implants Submitted to Immediate and Conventional Loading
TheScientificWorldJournal, 2014Co-Authors: Ana Emília Farias Pontes, Adriano Piattelli, Giovanna Iezzi, Fernando Salimon Ribeiro, Juliana Rico Pires, Elizangela Partata Zuza, Elcio Marcantonio JuniorAbstract:The present study aims to evaluate the influence of apicocoronal position and immediate and conventional loading in the percentage of bone-Implant Contact (BIC). Thus, 36 Implants were inserted in the edentulous mandible from six dogs. Three Implants were installed in each hemimandible, in different positions in relation to the ridge: Bone Level (at crestal bone level), Minus 1 (one millimeter apical to crestal bone), and Minus 2 (two millimeters apical to crestal bone). In addition, each hemimandible was submitted to a loading protocol: immediate (prosthesis installed 24 hours after Implantation) or conventional (prosthesis installed 120 days after Implantation). Ninety days after, animals were killed, and Implant and adjacent tissues were prepared for histometric analysis. BIC values from immediate loaded Implants were 58.7%, 57.7%, and 51.1%, respectively, while conventional loaded Implants were 61.8%, 53.8%, and 68.4%. Differences statistically significant were not observed among groups (P = 0.10, ANOVA test). These findings suggest that different apicocoronal positioning and loading protocols evaluated did not interfere in the percentage of bone-Implant Contact, suggesting that these procedures did not jeopardize osseointegration.
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bone to Implant Contact around immediately loaded direct laser metal forming transitional Implants in human posterior maxilla
Journal of Periodontology, 2013Co-Authors: Jamil Awad Shibli, Giovanna Iezzi, Carlo Mangano, Francesco Mangano, Jose Augusto Rodrigues, Alessandra Cassoni, Karen Bechara, Jose Divino B Ferreia, Alexandre M Dottore, Adriano PiattelliAbstract:Objective: Direct laser metal forming (DLMF) is a procedure in which a high-power laser beam is directed onto a metal powder bed and programmed to fuse particles according to a computer-aided design file, generating a thin metal layer. This histologic study evaluated the bone-to-Implant Contact (BIC%) around immediately loaded DLMF transitional Implants retrieved after 2 months from posterior human maxillae.Methods: Twelve totally edentulous individuals (mean age, 66.14 ± 2.11 years) received DLMF transitional Implants divided in twelve immediately loaded (IL) and twelve unloaded (UI) Implants. These transitional Implants were placed between conventional Implants to support the interim complete maxillary denture during the healing period. After 8 weeks, the transitional Implants and the surrounding tissue were removed and prepared for histomorphometric analysis.Results: Mature woven preexisting bone lined by newly formed bone in early stages of maturation were found around all retrieved Implants. Histomet...
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Mineralized bone-Implant Contact and Implant stability quotient in 16 human Implants retrieved after early healing periods: a histologic and histomorphometric evaluation.
The International journal of oral & maxillofacial implants, 2010Co-Authors: Marco Degidi, Adriano Piattelli, Vittoria Perrotti, Giovanna IezziAbstract:PURPOSE Resonance frequency analysis (RFA) is a quantitative method for the measurement of Implant stability. Information about the significance of RFA measurements and the relationship between RFA values and Implant osseointegration, success, or failure is important from a clinical point of view. In a previous study the authors observed a strong correlation between RFA values and mineralized bone-Implant Contact percentage in Implants retrieved after 6 months. The aim of the present histologic and histomorphometric study was to determine whether the same correlation existed at earlier time points, specifically in Implants retrieved after 4 or 8 weeks. MATERIALS AND METHODS Sixteen Implants, all with a sandblasted and acid-etched surface, were evaluated in the present study. The Implants were retrieved for different reasons after 4 or 8 weeks of healing with a 5-mm trephine bur and immersed in 10% buffered formalin to be processed for histology. RESULTS A statistically insignificant correlation was detected between RFA values and mineralized bone-Implant Contact percentage (P = or < .5502) using the Friedman and Spearman tests. CONCLUSION RFA should reflect the bone anchorage of the Implant; however, the relationship between bone structure and RFA is not fully understood.
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Is insertion torque correlated to bone-Implant Contact percentage in the early healing period? A histological and histomorphometrical evaluation of 17 human-retrieved dental Implants.
Clinical Oral Implants Research, 2009Co-Authors: Marco Degidi, Adriano Piattelli, Vittoria Perrotti, Rita Strocchi, Giovanna IezziAbstract:Objective: A precise and scientifically established method for the evaluation of the bone quality/primary stability is the measure of the insertion torque (IT). The aim of this study was a comparison between the IT values and the bone–Implant Contact percentage (BIC) of human Implants retrieved after a 4/8-week healing period. Materials: Seventeen Implants, all with a sandblasted and acid-etched surface, were evaluated in the present study. Methods: The Implants had been retrieved for different causes, after 4/8 weeks, with a 5 mm trephine bur, and immersed in 10% buffered formalin to be processed for histology. Results: A not statistically significant correlation was found between IT and BIC (P≤0.892). Conclusions: In the present study on human-retrieved Implants, no statistically significant correlation was found between the IT values and BIC. These results could be due to a lack of relationship between bone structure and IT, or to the fact that primary stability may not only be influenced by bone volumetrical density and/or bone trabecular connectivity but also by the thickness and density of the cortical layer. Moreover, the present knowledge of the bone microstructure is not enough to explain the relationship of bone quality and primary Implant stability.
Maria Letizia Raffa - One of the best experts on this subject based on the ideXlab platform.
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stress shielding at the bone Implant interface influence of surface roughness and of the bone Implant Contact ratio
Journal of Orthopaedic Research, 2020Co-Authors: Maria Letizia Raffa, Vuhieu Nguyen, Philippe Hernigou, Charleshenri Flouzatlachaniette, Guillaume HaiatAbstract:Short and long-term stabilities of cementless Implants are strongly determined by the interfacial load transfer between Implants and bone tissue. Stress-shielding effects arise from shear stresses due to the difference of material properties between bone and the Implant. It remains difficult to measure the stress field in periprosthetic bone tissue. This study proposes to investigate the dependence of the stress field in periprosthetic bone tissue on i) the Implant surface roughness, ii) material properties of bone and of the Implant, iii) the bone-Implant Contact ratio. To do so, a microscale 2-D finite element model of an osseointegrated bone-Implant interface was developed where the surface roughness was modeled by a sinusoidal surface. The results show that the isostatic pressure is not affected by the presence of the bone-Implant interface while shear stresses arise due to the combined effects of a geometrical singularity (for low surface roughness) and of shear stresses at the bone-Implant interface (for high surface roughness). Stress-shielding effects are likely to be more important when the bone-Implant Contact ratio value is low, which corresponds to a case of relatively low Implant stability. Shear stress reach a maximum value at a distance from the interface comprised between 0 and 0.1 time roughness wavelength λ and tend to 0 at a distance from the Implant surface higher than λ, independently from bone-Implant Contact ratio and waviness ratio. A comparison with an analytical model allows validating the numerical results. Future work should use the present approach to model osseointegration phenomena. This article is protected by copyright. All rights reserved.
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stress shielding at the bone Implant interface influence of surface roughness and of the bone Implant Contact ratio
Journal of Orthopaedic Research, 2020Co-Authors: Maria Letizia Raffa, Vuhieu Nguyen, Philippe Hernigou, Charleshenri Flouzatlachaniette, Guillaume HaiatAbstract:Short and long-term stabilities of cementless Implants are strongly determined by the interfacial load transfer between Implants and bone tissue. Stress-shielding effects arise from shear stresses due to the difference of material properties between bone and the Implant. It remains difficult to measure the stress field in periprosthetic bone tissue. This study proposes to investigate the dependence of the stress field in periprosthetic bone tissue on (i) the Implant surface roughness, (ii) the material properties of bone and of the Implant, (iii) the bone-Implant Contact ratio. To do so, a microscale two-dimensional finite element model of an osseointegrated bone-Implant interface was developed where the surface roughness was modeled by a sinusoidal surface. The results show that the isostatic pressure is not affected by the presence of the bone-Implant interface while shear stresses arise due to the combined effects of a geometrical singularity (for low surface roughness) and of shear stresses at the bone-Implant interface (for high surface roughness). Stress-shielding effects are likely to be more important when the bone-Implant Contact ratio value is low, which corresponds to a case of relatively low Implant stability. Shear stress reach a maximum value at a distance from the interface comprised between 0 and 0.1 time roughness wavelength λ and tend to 0 at a distance from the Implant surface higher than λ, independently from bone-Implant Contact ratio and waviness ratio. A comparison with an analytical model allows validating the numerical results. Future work should use the present approach to model osseointegration phenomena.
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Stress shielding at the bone‐Implant interface: influence of surface roughness and of the bone‐Implant Contact ratio
Journal of Orthopaedic Research, 2020Co-Authors: Maria Letizia Raffa, Vuhieu Nguyen, Philippe Hernigou, Charles-henri Flouzat- Lachaniette, Guillaume HaiatAbstract:Short and long-term stabilities of cementless Implants are strongly determined by the interfacial load transfer between Implants and bone tissue. Stress-shielding effects arise from shear stresses due to the difference of material properties between bone and the Implant. It remains difficult to measure the stress field in periprosthetic bone tissue. This study proposes to investigate the dependence of the stress field in periprosthetic bone tissue on i) the Implant surface roughness, ii) material properties of bone and of the Implant, iii) the bone-Implant Contact ratio. To do so, a microscale 2-D finite element model of an osseointegrated boneImplant interface was developed where the surface roughness was modeled by a sinusoidal surface. The results show that the isostatic pressure is not affected by the presence of the bone-Implant interface while shear stresses arise due to the combined effects of a geometrical singularity (for low surface roughness) and of shear stresses at the bone-Implant interface (for high surface roughness). Stress-shielding effects are likely to be more important when the bone-Implant Contact ratio value is low, which corresponds to a case of relatively low Implant stability. Shear stress reach a maximum value at a distance from the interface comprised between 0 and 0.1 time roughness wavelength λ and tend to 0 at a distance from the Implant surface higher than λ, independently from bone-Implant Contact ratio and waviness ratio. A comparison with an analytical model allows validating the numerical results. Future work should use the present approach to model osseointegration phenomena.