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Abstract
PURPOSE Occlusal overload may cause implant biomechanical failures, marginal bone loss, or even complete loss of osseointegration. Thus, it is important for clinicians to understand the role of occlusion in implant long-term stability. This systematic review updates the understanding of occlusion on dental implants, the impact on the surrounding peri-implant tissues, and the effects of occlusal overload on implants. Additionally, recommendations of occlusal scheme for implant prostheses and designs were formulated. MATERIALS AND METHODS Two reviewers completed a literature search using the PubMed database and a manual search of relevant journals. Relevant articles from January 1950 to September 20, 2015 published in the English language were considered. RESULTS Recommendations for implant occlusion are lacking in the literature. Despite this, implant occlusion should be carefully addressed. CONCLUSION Recommendations for occlusal schemes for single implants or fixed partial denture supported by implants include a mutually protected occlusion with anterior guidance and evenly distributed contacts with wide freedom in centric relation. Suggestions to reduce occlusal overload include reducing cantilevers, increasing the number of implants, increasing contact points, monitoring for parafunctional habits, narrowing the occlusal table, decreasing cuspal inclines, and using progressive loading in patients with poor bone quality. Protecting the implant and surrounding peri-implant bone requires an understanding of how occlusion plays a role in influencing long-term implant stability.
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Kuroshima S, Kaku M, Ishimoto T, Sasaki M, Nakano T, Sawase T. A paradigm shift for bone quality in dentistry: A literature review. J Prosthodont Res 2017. [PMID: 28633987 DOI: 10.1016/j.jpor.2017.05.006] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
PURPOSE The aim of this study was to present the current concept of bone quality based on the proposal by the National Institutes of Health (NIH) and some of the cellular and molecular factors that affect bone quality. STUDY SELECTION This is a literature review which focuses on collagen, biological apatite (BAp), and bone cells such as osteoblasts and osteocytes. RESULTS In dentistry, the term "bone quality" has long been considered to be synonymous with bone mineral density (BMD) based on radiographic and sensible evaluations. In 2000, the NIH proposed the concept of bone quality as "the sum of all characteristics of bone that influence the bone's resistance to fracture," which is completely independent of BMD. The NIH defines bone quality as comprising bone architecture, bone turnover, bone mineralization, and micro-damage accumulation. Moreover, our investigations have demonstrated that BAp, collagen, and bone cells such as osteoblasts and osteocytes play essential roles in controlling the current concept of bone quality in bone around hip and dental implants. CONCLUSION The current concept of bone quality is crucial for understanding bone mechanical functions. BAp, collagen and osteocytes are the main factors affecting bone quality. Moreover, mechanical loading dynamically adapts bone quality. Understanding the current concept of bone quality is required in dentistry.
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Affiliation(s)
- Shinichiro Kuroshima
- Department of Applied Prosthodontics, Graduate School of Biomedical Sciences, Nagasaki University, 1-7-1, Sakamoto, Nagasaki-city, Nagasaki 852-8588, Japan.
| | - Masaru Kaku
- Division of Bio-prosthodontics, Graduate School of Medical and Dental Science, Niigata University, 2-5274, Gakkocho-dori, Chuo-ku, Niigata-City, Niigata 951-8514, Japan
| | - Takuya Ishimoto
- Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, 2-1, Yamadaoka, Suita-city, Osaka 565-0871, Japan
| | - Muneteru Sasaki
- Department of Applied Prosthodontics, Graduate School of Biomedical Sciences, Nagasaki University, 1-7-1, Sakamoto, Nagasaki-city, Nagasaki 852-8588, Japan
| | - Takayoshi Nakano
- Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, 2-1, Yamadaoka, Suita-city, Osaka 565-0871, Japan
| | - Takashi Sawase
- Department of Applied Prosthodontics, Graduate School of Biomedical Sciences, Nagasaki University, 1-7-1, Sakamoto, Nagasaki-city, Nagasaki 852-8588, Japan
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Jariwala SH, Wee H, Roush EP, Whitcomb TL, Murter C, Kozlansky G, Lakhtakia A, Kunselman AR, Donahue HJ, Armstrong AD, Lewis GS. Time course of peri-implant bone regeneration around loaded and unloaded implants in a rat model. J Orthop Res 2017; 35:997-1006. [PMID: 27381807 PMCID: PMC5800527 DOI: 10.1002/jor.23360] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 07/02/2016] [Indexed: 02/04/2023]
Abstract
The time-course of cancellous bone regeneration surrounding mechanically loaded implants affects implant fixation, and is relevant to determining optimal rehabilitation protocols following orthopaedic surgeries. We investigated the influence of controlled mechanical loading of titanium-coated polyether-ether ketone (PEEK) implants on osseointegration using time-lapsed, non-invasive, in vivo micro-computed tomography (micro-CT) scans. Implants were inserted into proximal tibial metaphyses of both limbs of eight female Sprague-Dawley rats. External cyclic loading (60 or 100 μm displacement, 1 Hz, 60 s) was applied every other day for 14 days to one implant in each rat, while implants in contralateral limbs served as the unloaded controls. Hind limbs were imaged with high-resolution micro-CT (12.5 μm voxel size) at 2, 5, 9, and 12 days post-surgery. Trabecular changes over time were detected by 3D image registration allowing for measurements of bone-formation rate (BFR) and bone-resorption rate (BRR). At day 9, mean %BV/TV for loaded and unloaded limbs were 35.5 ± 10.0% and 37.2 ± 10.0%, respectively, and demonstrated significant increases in bone volume compared to day 2. BRR increased significantly after day 9. No significant differences between bone volumes, BFR, and BRR were detected due to implant loading. Although not reaching significance (p = 0.16), an average 119% increase in pull-out strength was measured in the loaded implants. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:997-1006, 2017.
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Affiliation(s)
- Shailly H. Jariwala
- Division of Musculoskeletal Sciences, Department of Orthopedics and Rehabilitation, College of Medicine, Pennsylvania State University, Hershey, PA 17033
| | - Hwabok Wee
- Division of Musculoskeletal Sciences, Department of Orthopedics and Rehabilitation, College of Medicine, Pennsylvania State University, Hershey, PA 17033
| | - Evan P. Roush
- Division of Musculoskeletal Sciences, Department of Orthopedics and Rehabilitation, College of Medicine, Pennsylvania State University, Hershey, PA 17033
| | - Tiffany L. Whitcomb
- Department of Comparative Medicine, Pennsylvania State University College of Medicine, Hershey, PA 17033
| | - Christopher Murter
- Division of Musculoskeletal Sciences, Department of Orthopedics and Rehabilitation, College of Medicine, Pennsylvania State University, Hershey, PA 17033
| | - Gery Kozlansky
- Division of Musculoskeletal Sciences, Department of Orthopedics and Rehabilitation, College of Medicine, Pennsylvania State University, Hershey, PA 17033
| | - Akhlesh Lakhtakia
- Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, PA 16802-6812
| | - Allen R. Kunselman
- Department of Public Health Sciences, Pennsylvania State University College of Medicine, Hershey, PA 17033
| | - Henry J. Donahue
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, VA 23284
| | - April D. Armstrong
- Division of Musculoskeletal Sciences, Department of Orthopedics and Rehabilitation, College of Medicine, Pennsylvania State University, Hershey, PA 17033
| | - Gregory S. Lewis
- Division of Musculoskeletal Sciences, Department of Orthopedics and Rehabilitation, College of Medicine, Pennsylvania State University, Hershey, PA 17033
- Author to whom all correspondence should be addressed: Gregory S. Lewis, Ph.D*, Pennsylvania State University College of Medicine, 500 University Drive, Mailbox – H089, Hershey, PA-17033, Phone: (717) 531-5244, Fax no.: (717) 531-7583,
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Koller CD, Pereira-Cenci T, Boscato N. Parameters Associated with Marginal Bone Loss around Implant after Prosthetic Loading. Braz Dent J 2017; 27:292-7. [PMID: 27224562 DOI: 10.1590/0103-6440201600874] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 04/19/2016] [Indexed: 12/29/2022] Open
Abstract
This study evaluated retrospectively the association among occlusal, periodontal and implant-prosthetic parameters and marginal bone loss (MBL) around implants and survival rate at 5.7 ±3.2 years of follow-up after prosthetic loading. Eighty-two patients received 164 external hexagon implants. After the standard healing period (3 to 6 months), the implants were restored with single-tooth or up to three splinted crowns. All patients were followed according to a strict maintenance program with regular recalls and clinically evaluated by a calibrated examiner. The MBL measurements taken from standardized radiographs made at permanent crown placement (baseline) and after the last evaluation were calculated considering occlusal, periodontal and implant-prosthetic parameters. Veneer fractures and abutment loosening were not considered failure. Two implants failed during the follow-up period, resulting in a survival rate of 98.8%. Cox regression analyses showed MBL associated with non-working side contacts (p=0.047), inadequate anterior guidance (p=0.001), lateral group guidance involving teeth and implants (p=0.015), periimplant plaque index (p=0.035), prosthetic design (p=0.030) and retention (p=0.006). Inadequate occlusal pattern guide, presence of visible plaque, and cemented and splinted implant-supported restoration were associated with greater MBL around the implant.
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Affiliation(s)
- Clarissa D Koller
- Graduate Program in Dentistry, Dental School, UFPel - Universidade Federal de Pelotas, Pelotas, RS, Brazil, Universidade Federal de Pelotas, Graduate Program in Dentistry, Dental School, Universidade Federal de Pelotas, Pelotas RS , Brazil
| | - Tatiana Pereira-Cenci
- Graduate Program in Dentistry, Dental School, UFPel - Universidade Federal de Pelotas, Pelotas, RS, Brazil, Universidade Federal de Pelotas, Graduate Program in Dentistry, Dental School, Universidade Federal de Pelotas, Pelotas RS , Brazil
| | - Noéli Boscato
- Graduate Program in Dentistry, Dental School, UFPel - Universidade Federal de Pelotas, Pelotas, RS, Brazil, Universidade Federal de Pelotas, Graduate Program in Dentistry, Dental School, Universidade Federal de Pelotas, Pelotas RS , Brazil
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Parmigiani-Izquierdo JM, Cabaña-Muñoz ME, Merino JJ, Sánchez-Pérez A. Zirconia implants and peek restorations for the replacement of upper molars. Int J Implant Dent 2017; 3:5. [PMID: 28220366 PMCID: PMC5318309 DOI: 10.1186/s40729-016-0062-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Accepted: 12/22/2016] [Indexed: 11/22/2022] Open
Abstract
Background One of the disadvantages of the zirconia implants is the lack of elasticity, which is increased with the use of ceramic or zirconia crowns. The consequences that could result from this lack of elasticity have led to the search for new materials with improved mechanical properties. Case presentation A patient who is a 45-year-old woman, non-smoker and has no medical record of interest with a longitudinal fracture in the palatal root of molar tooth 1.7 and absence of tooth 1.6 was selected in order to receive a zirconia implant with a PEEK-based restoration and a composite coating. The following case report describes and analyses treatment with zirconia implants in molars following a flapless surgical technique. Zirconia implants are an alternative to titanium implants in patients with allergies or who are sensitive to metal alloys. However, one of the disadvantages that they have is their lack of elasticity, which increases with the use of ceramic or zirconia crowns. The consequences that can arise from this lack of elasticity have led to the search for new materials with better mechanical properties to cushion occlusal loads. PEEK-based restoration in implant prosthetics can compensate these occlusal forces, facilitating cushioning while chewing. Conclusion This procedure provides excellent elasticity and resembles natural tooth structure. This clinical case suggests that PEEK restorations can be used in zirconia implants in dentistry.
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Affiliation(s)
| | | | | | - Arturo Sánchez-Pérez
- Periodontics Unit, Faculty of Medicine and Dentistry, University of Murcia (Spain), Murcia, Spain. .,Clínica Odontologíca Universitaria, Hospital Morales Meseguer, 2ª planta, C/ Marqués de los Vélez s/n, Murcia, 30008, Spain.
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Menini M, Pesce P, Pera F, Barberis F, Lagazzo A, Bertola L, Pera P. Biological and mechanical characterization of carbon fiber frameworks for dental implant applications. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2017; 70:646-655. [DOI: 10.1016/j.msec.2016.09.047] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Revised: 09/04/2016] [Accepted: 09/21/2016] [Indexed: 10/21/2022]
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Douglas de Oliveira DW, Lages FS, Lanza LA, Gomes AM, Queiroz TP, Costa FDO. Dental Implants With Immediate Loading Using Insertion Torque of 30 Ncm: A Systematic Review. IMPLANT DENT 2016; 25:675-83. [PMID: 27540837 DOI: 10.1097/id.0000000000000444] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVE This study aimed to perform a review of the literature regarding the survival rate of dental implants with immediate loading using insertion torque of 30 Ncm. MATERIAL AND METHODS A systematic review was performed based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses and the Cochrane Handbook for Systematic Reviews of Interventions (PROSPERO CRD42014015323). The search was performed in the PubMed, Web of Science, Cochrane Library electronic, OVID, and Scielo databases. Manual searches were also performed. The articles identified were assessed independently by 3 researchers. Clinical trials reporting dental implants with immediate loading and 30 Ncm torque in patients ages 18 years or older were included. RESULTS The searches yielded 589 studies. Six studies were included in the systematic review. The survival rate of dental implants was 96.8%. Three studies showed a low potential risk of bias. CONCLUSION There is not strong evidence that insertion torque of 30 Ncm is enough for implant survival in cases of immediate loading.
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Affiliation(s)
- Dhelfeson Willya Douglas de Oliveira
- *PhD Student, Department of Periodontology, School of Dentistry, Federal University of Minas Gerais, Belo Horizonte, Brazil. †Professor, Implantology Post-Graduation Program, University Center of Araraquara, Araraquara, Brazil. ‡Professor, Department of Periodontology, School of Dentistry, Federal University of Minas Gerais, Belo Horizonte, Brazil
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Horita S, Sugiura T, Yamamoto K, Murakami K, Imai Y, Kirita T. Biomechanical analysis of immediately loaded implants according to the "All-on-Four" concept. J Prosthodont Res 2016; 61:123-132. [PMID: 27615425 DOI: 10.1016/j.jpor.2016.08.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2015] [Revised: 07/06/2016] [Accepted: 08/08/2016] [Indexed: 11/15/2022]
Abstract
PURPOSE The purpose of this study was to investigate the biomechanical behavior of immediately loaded implants in an edentulous mandible according to the "All-on-Four" concept. METHODS A 3D-finite element model of an edentulous mandible was constructed. Four implants were placed between the bilateral mental foramen according to "All-on-Four" concept. A framework made of titanium or acrylic resin between the bilateral first molars was modeled. Immediate loading and a delayed loading protocol were simulated. A vertical load of 200N was applied at the cantilever or on the abutments region of the distal implants, simulating the absence of a cantilever. RESULTS The peak principal compressive strains in the immediate loading models resulted in 24.0-35.8% and 26.4-39.0% increases compared with the delayed loading models under non-cantilever loading and cantilever loading, respectively. The loading position greatly affected the principal compressive and tensile strain values. The peak principal compressive strains in non-cantilever loading resulted in a 45.3-52.6% reduction compared with those in cantilever loading. The framework material did not influence the peak compressive and tensile strain. The maximum micromotion at the bone-implant interface in the immediate loading models was 7.5-14.4μm. CONCLUSIONS Mandibular fixed full-arch prostheses without cantilevers may result in a favorable reduction of the peri-implant bone strain during the healing period, compared with cantilevers. The maximum micromotion was within the acceptable limits for uneventful implant osseointegration in the immediate loading models. Framework material did not play an important role in reducing the peri-implant bone strain and micromotion at the bone-implant interface.
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Affiliation(s)
- Satoshi Horita
- Department of Oral and Maxillofacial Surgery, Nara Medical University, Nara, Japan.
| | - Tsutomu Sugiura
- Department of Oral and Maxillofacial Surgery, Nara Medical University, Nara, Japan
| | - Kazuhiko Yamamoto
- Department of Oral and Maxillofacial Surgery, Nara Medical University, Nara, Japan
| | - Kazuhiro Murakami
- Department of Oral and Maxillofacial Surgery, Nara Medical University, Nara, Japan
| | - Yuichiro Imai
- Department of Oral and Maxillofacial Surgery, Nara Medical University, Nara, Japan
| | - Tadaaki Kirita
- Department of Oral and Maxillofacial Surgery, Nara Medical University, Nara, Japan
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MANNARINO FS, FRANCISCHONE JÚNIOR CE, CARVALHO RSD, SOTTO-MAIOR BS, FRANCISCHONE CE. Analysis of the distribution of stress and deformation in single implant-supported prosthetic units in implants of different diameters. REVISTA DE ODONTOLOGIA DA UNESP 2016. [DOI: 10.1590/1807-2577.02716] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Abstract Introduction When stress and strain levels in the bone-implant system exceed It's capacity, a mechanical fatigue occurs, resulting in collapse and loss of osseointegration. Objective Analyze biomechanical behavior in single implant-supported prosthesis with implants of different diameters in the posterior mandible. Material and method Three different finite element models of Cone-Morse implants with the same height were created, varying the diameter (3.3 mm, 4.1 mm and 4.8 mm). The mandibular first molar area was the location of the implant, with It´s component and overlying prosthetic crown. The jawbone was composed of cortical and cancellous bone. Refined mesh of 0.5 mm was created in the critical interfaces to be analyzed. The loading of the models was performed at the point of occlusal contact with an occlusal load of 400 N. Result Maximum stress and strain occurred in the cervical regions of the implants in all groups, either in the implants or in components as well as in the analysis of cortical bone. The greater the diameter, the lower the stress and strain found in the implant. The 3.3 mm group had the highest strain in peri-implant cortical bone, and the 4.1 mm group had the smallest deformation, significantly lower than in the 4.8 mm group. Conclusion Although the biggest implant diameter (4.8 mm) appears to have lower values of stress and strain, the group of intermediate implant diameter (4.1 mm) showed less deformation rate in the cortical peri-implant bone. Therefore it is concluded that the 4.1 mm implant platform presented a more biomechanically effective peri-implant bone maintenance.
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McDermott AM, Mason DE, Lin ASP, Guldberg RE, Boerckel JD. Influence of structural load-bearing scaffolds on mechanical load- and BMP-2-mediated bone regeneration. J Mech Behav Biomed Mater 2016; 62:169-181. [PMID: 27208510 DOI: 10.1016/j.jmbbm.2016.05.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Revised: 05/04/2016] [Accepted: 05/05/2016] [Indexed: 01/03/2023]
Abstract
A common design constraint in functional tissue engineering is that scaffolds intended for use in load-bearing sites possess similar mechanical properties to the replaced tissue. Here, we tested the hypothesis that in vivo loading would enhance bone morphogenetic protein-2 (BMP-2)-mediated bone regeneration in the presence of a load-bearing PLDL scaffold, whose pores and central core were filled with BMP-2-releasing alginate hydrogel. First, we evaluated the effects of in vivo mechanical loading on bone regeneration in the structural scaffolds. Second, we compared scaffold-mediated bone regeneration, independent of mechanical loading, with alginate hydrogel constructs, without the structural scaffold, that have been shown previously to facilitate in vivo mechanical stimulation of bone formation. Contrary to our hypothesis, mechanical loading had no effect on bone formation, distribution, or biomechanical properties in structural scaffolds. Independent of loading, the structural scaffolds reduced bone formation compared to non-structural alginate, particularly in regions in which the scaffold was concentrated, resulting in impaired functional regeneration. This is attributable to a combination of stress shielding by the scaffold and inhibition of cellular infiltration and tissue ingrowth. Collectively, these data question the necessity of scaffold similarity to mature tissue at the time of implantation and emphasize development of an environment conducive to cellular activation of matrix production and ultimate functional regeneration.
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Affiliation(s)
- Anna M McDermott
- Department of Aerospace and Mechanical Engineering, Bioengineering Graduate Program, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Devon E Mason
- Department of Aerospace and Mechanical Engineering, Bioengineering Graduate Program, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Angela S P Lin
- Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Robert E Guldberg
- Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Joel D Boerckel
- Department of Aerospace and Mechanical Engineering, Bioengineering Graduate Program, University of Notre Dame, Notre Dame, IN 46556, USA.
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Pellegrini G, Canullo L, Dellavia C. Histological features of peri-implant bone subjected to overload. Ann Anat 2016; 206:57-63. [DOI: 10.1016/j.aanat.2015.02.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Revised: 01/13/2015] [Accepted: 02/11/2015] [Indexed: 11/25/2022]
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Correlation Between Stress Distributions and Biological Reactions in Bone Surrounding Implants That Support Cantilevers in Supraocclusal Contact in Rats. IMPLANT DENT 2015; 25:204-13. [PMID: 26695704 DOI: 10.1097/id.0000000000000369] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To investigate the relationship between stress distributions and peri-implant bone reactions around maxillary implants that support cantilevers in supraocclusal contact. MATERIALS AND METHODS After molar extraction, 16 Wistar rats received a titanium implant unilaterally. After healing, 8 rats (control group) were killed and the others received implant-supported cantilever superstructures in supraocclusion (loaded group). After 5 days, they were killed. The maxillae of all rats were scanned by microcomputed tomography (μ-CT). Based on the μ-CT images, bone volumes were measured. For the loaded group, 3D finite element models were created and analyzed under 20-N vertical and 5-N lateral forces, successively. After μ-CT scanning, sections were prepared and observed histologically. RESULTS When compared with the controls, the bone volume tended to decrease in the loaded group, but the difference was not statistically significant. On average, marginal bone resorption and stresses tended to be higher in 2 rats that occluded on the cantilever arm than in the others, which occluded right on the implant, nevertheless, calculated stress did not surpass the maximum elastic stress (yielding strength) of rat bone. However, at the implant-bone interface of these samples, partial bone resorption surrounded by signs of active resorption was histologically found. CONCLUSION These findings suggest that in this occlusally loaded rat model, the stress distributions correlated to some extent with bone volume and morphological changes observed on μ-CT images and histological sections.
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Protocol for Bone Augmentation with Simultaneous Early Implant Placement: A Retrospective Multicenter Clinical Study. Int J Dent 2015; 2015:589135. [PMID: 26858757 PMCID: PMC4672140 DOI: 10.1155/2015/589135] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Revised: 11/10/2015] [Accepted: 11/11/2015] [Indexed: 12/31/2022] Open
Abstract
Purpose. To present a novel protocol for alveolar bone regeneration in parallel to early implant placement. Methods. 497 patients in need of extraction and early implant placement with simultaneous bone augmentation were treated in a period of 10 years. In all patients the same specific method was followed and grafting was performed utilizing in situ hardening fully resorbable alloplastic grafting materials consisting of β-tricalcium phosphate and calcium sulfate. The protocol involved atraumatic extraction, implant placement after 4 weeks with simultaneous bone augmentation, and loading of the implant 12 weeks after placement and grafting. Follow-up periods ranged from 6 months to 10 years (mean of 4 years). Results. A total of 601 postextraction sites were rehabilitated in 497 patients utilizing the novel protocol. Three implants failed before loading and three implants failed one year after loading, leaving an overall survival rate of 99.0%. Conclusions. This standardized protocol allows successful long-term functional results regarding alveolar bone regeneration and implant rehabilitation. The concept of placing the implant 4 weeks after extraction, augmenting the bone around the implant utilizing fully resorbable, biomechanically stable, alloplastic materials, and loading the implant at 12 weeks seems to offer advantages when compared with traditional treatment modalities.
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Han P, Cheng P, Zhang S, Zhao C, Ni J, Zhang Y, Zhong W, Hou P, Zhang X, Zheng Y, Chai Y. In vitro and in vivo studies on the degradation of high-purity Mg (99.99wt.%) screw with femoral intracondylar fractured rabbit model. Biomaterials 2015; 64:57-69. [PMID: 26117658 DOI: 10.1016/j.biomaterials.2015.06.031] [Citation(s) in RCA: 114] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Revised: 06/12/2015] [Accepted: 06/18/2015] [Indexed: 01/07/2023]
Abstract
High-purity magnesium (HP Mg) takes advantage in no alloying toxic elements and slower degradation rate in lack of second phases and micro-galvanic corrosion. In this study, as rolled HP Mg was fabricated into screws and went through in vitro immersion tests, cytotoxicity test and bioactive analysis. The HP Mg screws performed uniform corrosion behavior in vitro, and its extraction promoted cell viability, bone alkaline phosphatase (ALP) activity, and mRNA expression of osteogenic differentiation related gene, i.e. ALP, osteopontin (OPN) and RUNX2 of human bone marrow mesenchymal stem cells (hBMSCs). Then HP Mg screws were implanted in vivo as load-bearing implant to fix bone fracture and subsequently gross observation, range of motion (ROM), X-ray scanning, qualitative micro-computed tomography (μCT) analysis, histological analysis, bending-force test and SEM morphology of retrieved screws were performed respectively at 4, 8, 16 and 24 weeks. As a result, the retrieved HP Mg screws in fixation of rabbit femoral intracondylar fracture showed uniform degradation morphology and enough bending force. However, part of PLLA screws was broken in bolt, although its screw thread was still intact. Good osseointegration was revealed surrounding HP Mg screws and increased bone volume and bone mineral density were detected at fracture gap, indicating the rigid fixation and enhanced fracture healing process provided by HP Mg screws. Consequently, the HP Mg showed great potential as internal fixation devices in intra-articular fracture operation.
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Affiliation(s)
- Pei Han
- Orthopaedic Department, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, China
| | - Pengfei Cheng
- Orthopaedic Department, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, China
| | - Shaoxiang Zhang
- State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China; Suzhou Origin Medical Technology Co. Ltd., Suzhou 215513, China
| | - Changli Zhao
- State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
| | - Jiahua Ni
- State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | | | - Wanrun Zhong
- Orthopaedic Department, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, China
| | - Peng Hou
- Orthopaedic Department, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, China
| | - Xiaonong Zhang
- State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China; Suzhou Origin Medical Technology Co. Ltd., Suzhou 215513, China
| | - Yufeng Zheng
- Department of Advanced Materials and Nanotechnology, College of Engineering, Peking University, Beijing 100871, China
| | - Yimin Chai
- Orthopaedic Department, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, China.
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dos Santos MB, Caldas RA, Zen BM, Bacchi A, Correr-Sobrinho L. Adaptation of overdenture-bars casted in different metals and their influence on the stress distribution—A laboratory and 3D FEA. J Biomech 2015; 48:8-13. [DOI: 10.1016/j.jbiomech.2014.11.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Revised: 11/10/2014] [Accepted: 11/11/2014] [Indexed: 11/26/2022]
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