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Special Issue "Osseointegrated Oral implants: Mechanisms of Implant Anchorage, Threats and Long-Term Survival Rates"

A special issue of Journal of Clinical Medicine (ISSN 2077-0383). This special issue belongs to the section "Stomatology".

Deadline for manuscript submissions: 20 July 2019

Special Issue Editor

Guest Editor
Prof. Tomas Albrektsson

Department of Biomaterials, Göteborg University, Göteborg, Sweden.
Website | E-Mail
Interests: oral implants; immunology; clinical results; orthopaedic implants; craniofacial implants

Special Issue Information

Dear Colleagues,

In the past, osseointegration was regarded to be a mode of implant anchorage that simulated a simple wound healing phenomenon. Today, we have evidence that osseointegration is, in fact, a foreign body reaction that involves an immunologically derived bony demarcation of an implant to shield it off from the tissues. Marginal bone resorption around an oral implant cannot be properly understood without realizing the foreign body nature of the implant itself. Whereas the immunological response as such is positive for implant longevity, adverse immunological reactions may cause marginal bone loss in combination with combined factors. Combined factors include the hardware, clinical handling as well as patient characteristics that, even if each one of these factors only produce subliminal trauma, when acting together they may result in loss of marginal bone. The role of bacteria in the process of marginal bone loss is smaller than previously believed due to combined defense mechanisms of inflammation and immunological reactions, but if the defense is failing we may see bacterially induced marginal bone loss as well. However, problems with loss of marginal bone threatening implant survival remains relatively uncommon; we have today 10 years of clinical documentation of five different types of implant displaying a failure rate in the range of only 1 to 4 %.

Prof. Tomas Albrektsson
Guest Editor

Manuscript Submission Information

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Keywords

  • oral implants
  • osseointegration
  • marginal bone loss
  • Immunology
  • clinical results

Published Papers (9 papers)

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Research

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Open AccessArticle
Osteogenic Cell Behavior on Titanium Surfaces in Hard Tissue
J. Clin. Med. 2019, 8(5), 604; https://doi.org/10.3390/jcm8050604
Received: 12 April 2019 / Revised: 26 April 2019 / Accepted: 28 April 2019 / Published: 2 May 2019
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Abstract
It is challenging to remove dental implants once they have been inserted into the bone because it is hard to visualize the actual process of bone formation after implant installation, not to mention the cellular events that occur therein. During bone formation, contact [...] Read more.
It is challenging to remove dental implants once they have been inserted into the bone because it is hard to visualize the actual process of bone formation after implant installation, not to mention the cellular events that occur therein. During bone formation, contact osteogenesis occurs on roughened implant surfaces, while distance osteogenesis occurs on smooth implant surfaces. In the literature, there have been many in vitro model studies of bone formation on simulated dental implants using flattened titanium (Ti) discs; however, the purpose of this study was to identify the in vivo cell responses to the implant surfaces on actual, three-dimensional (3D) dental Ti implants and the surrounding bone in contact with such implants at the electron microscopic level using two different types of implant surfaces. In particular, the different parts of the implant structures were scrutinized. In this study, dental implants were installed in rabbit tibiae. The implants and bone were removed on day 10 and, subsequently, assessed using scanning electron microscopy (SEM), immunofluorescence microscopy (IF), transmission electron microscopy (TEM), focused ion-beam (FIB) system with Cs-corrected TEM (Cs-STEM), and confocal laser scanning microscopy (CLSM)—which were used to determine the implant surface characteristics and to identify the cells according to the different structural parts of the turned and roughened implants. The cell attachment pattern was revealed according to the different structural components of each implant surface and bone. Different cell responses to the implant surfaces and the surrounding bone were attained at an electron microscopic level in an in vivo model. These results shed light on cell behavioral patterns that occur during bone regeneration and could be a guide in the use of electron microscopy for 3D dental implants in an in vivo model. Full article
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Open AccessArticle
Mechanical and Biological Advantages of a Tri-Oval Implant Design
J. Clin. Med. 2019, 8(4), 427; https://doi.org/10.3390/jcm8040427
Received: 2 February 2019 / Revised: 22 March 2019 / Accepted: 25 March 2019 / Published: 28 March 2019
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Abstract
Of all geometric shapes, a tri-oval one may be the strongest because of its capacity to bear large loads with neither rotation nor deformation. Here, we modified the external shape of a dental implant from circular to tri-oval, aiming to create a combination [...] Read more.
Of all geometric shapes, a tri-oval one may be the strongest because of its capacity to bear large loads with neither rotation nor deformation. Here, we modified the external shape of a dental implant from circular to tri-oval, aiming to create a combination of high strain and low strain peri-implant environment that would ensure both primary implant stability and rapid osseointegration, respectively. Using in vivo mouse models, we tested the effects of this geometric alteration on implant survival and osseointegration over time. The maxima regions of tri-oval implants provided superior primary stability without increasing insertion torque. The minima regions of tri-oval implants presented low compressive strain and significantly less osteocyte apoptosis, which led to minimal bone resorption compared to the round implants. The rate of new bone accrual was also faster around the tri-oval implants. We further subjected both round and tri-oval implants to occlusal loading immediately after placement. In contrast to the round implants that exhibited a significant dip in stability that eventually led to their failure, the tri-oval implants maintained their stability throughout the osseointegration period. Collectively, these multiscale biomechanical analyses demonstrated the superior in vivo performance of the tri-oval implant design. Full article
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Open AccessFeature PaperArticle
Carbon Fiber Reinforced PEEK Composites Based on 3D-Printing Technology for Orthopedic and Dental Applications
J. Clin. Med. 2019, 8(2), 240; https://doi.org/10.3390/jcm8020240
Received: 11 January 2019 / Revised: 31 January 2019 / Accepted: 5 February 2019 / Published: 12 February 2019
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Abstract
Fused deposition modeling (FDM) is a rapidly growing three-dimensional (3D) printing technology and has great potential in medicine. Polyether-ether-ketone (PEEK) is a biocompatible high-performance polymer, which is suitable to be used as an orthopedic/dental implant material. However, the mechanical properties and biocompatibility of [...] Read more.
Fused deposition modeling (FDM) is a rapidly growing three-dimensional (3D) printing technology and has great potential in medicine. Polyether-ether-ketone (PEEK) is a biocompatible high-performance polymer, which is suitable to be used as an orthopedic/dental implant material. However, the mechanical properties and biocompatibility of FDM-printed PEEK and its composites are still not clear. In this study, FDM-printed pure PEEK and carbon fiber reinforced PEEK (CFR-PEEK) composite were successfully fabricated by FDM and characterized by mechanical tests. Moreover, the sample surfaces were modified with polishing and sandblasting methods to analyze the influence of surface roughness and topography on general biocompatibility (cytotoxicity) and cell adhesion. The results indicated that the printed CFR-PEEK samples had significantly higher general mechanical strengths than the printed pure PEEK (even though there was no statistical difference in compressive strength). Both PEEK and CFR-PEEK materials showed good biocompatibility with and without surface modification. Cell densities on the “as-printed” PEEK and the CFR-PEEK sample surfaces were significantly higher than on the corresponding polished and sandblasted samples. Therefore, the FDM-printed CFR-PEEK composite with proper mechanical strengths has potential as a biomaterial for bone grafting and tissue engineering applications. Full article
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Open AccessArticle
A Novel Osteotomy Preparation Technique to Preserve Implant Site Viability and Enhance Osteogenesis
J. Clin. Med. 2019, 8(2), 170; https://doi.org/10.3390/jcm8020170
Received: 6 January 2019 / Revised: 26 January 2019 / Accepted: 27 January 2019 / Published: 1 February 2019
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Abstract
The preservation of bone viability at an osteotomy site is a critical variable for subsequent implant osseointegration. Recent biomechanical studies evaluating the consequences of site preparation led us to rethink the design of bone-cutting drills, especially those intended for implant site preparation. We [...] Read more.
The preservation of bone viability at an osteotomy site is a critical variable for subsequent implant osseointegration. Recent biomechanical studies evaluating the consequences of site preparation led us to rethink the design of bone-cutting drills, especially those intended for implant site preparation. We present here a novel drill design that is designed to efficiently cut bone at a very low rotational velocity, obviating the need for irrigation as a coolant. The low-speed cutting produces little heat and, consequently, osteocyte viability is maintained. The lack of irrigation, coupled with the unique design of the cutting flutes, channels into the osteotomy autologous bone chips and osseous coagulum that have inherent osteogenic potential. Collectively, these features result in robust, new bone formation at rates significantly faster than those observed with conventional drilling protocols. These preclinical data have practical implications for the clinical preparation of osteotomies and alveolar bone reconstructive surgeries. Full article
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Open AccessArticle
Bone Immune Response to Materials, Part I: Titanium, PEEK and Copper in Comparison to Sham at 10 Days in Rabbit Tibia
J. Clin. Med. 2018, 7(12), 526; https://doi.org/10.3390/jcm7120526
Received: 9 November 2018 / Revised: 2 December 2018 / Accepted: 5 December 2018 / Published: 7 December 2018
Cited by 5 | PDF Full-text (1925 KB) | HTML Full-text | XML Full-text
Abstract
Bone anchored biomaterials have become an indispensable solution for the restoration of lost dental elements and for skeletal joint replacements. However, a thorough understanding is still lacking in terms of the biological mechanisms leading to osseointegration and its contrast, unwanted peri-implant bone loss. [...] Read more.
Bone anchored biomaterials have become an indispensable solution for the restoration of lost dental elements and for skeletal joint replacements. However, a thorough understanding is still lacking in terms of the biological mechanisms leading to osseointegration and its contrast, unwanted peri-implant bone loss. We have previously hypothesized on the participation of immune mechanisms in such processes, and later demonstrated enhanced bone immune activation up to 4 weeks around titanium implants. The current experimental study explored and compared in a rabbit tibia model after 10 days of healing time, the bone inflammation/immunological reaction at mRNA level towards titanium, polyether ether ketone (PEEK) and copper compared to a Sham control. Samples from the test and control sites were, after a healing period, processed for gene expression analysis (polymerase chain reaction, (qPCR)) and decalcified histology tissue analysis. All materials displayed immune activation and suppression of bone resorption, when compared to sham. The M1 (inflammatory)/M2 (reparative) -macrophage phenotype balance was correlated to the proximity and volume of bone growth at the implant vicinity, with titanium demonstrating a M2-phenotype at 10 days, whereas copper and PEEK were still dealing with a mixed M1- and M2-phenotype environment. Titanium was the only material showing adequate bone growth and proximity inside the implant threads. There was a consistent upregulation of (T-cell surface glycoprotein CD4) CD4 and downregulation of (T-cell transmembrane glycoprotein CD8) CD8, indicating a CD4-lymphocyte phenotype driven reaction around all materials at 10 days. Full article
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Review

Jump to: Research

Open AccessFeature PaperReview
Understanding Peri-Implantitis as a Plaque-Associated and Site-Specific Entity: On the Local Predisposing Factors
J. Clin. Med. 2019, 8(2), 279; https://doi.org/10.3390/jcm8020279
Received: 31 January 2019 / Revised: 20 February 2019 / Accepted: 21 February 2019 / Published: 25 February 2019
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Abstract
The prevalence of implant biological complications has grown enormously over the last decade, in concordance with the impact of biofilm and its byproducts upon disease development. Deleterious habits and systemic conditions have been regarded as risk factors for peri-implantitis. However, little is known [...] Read more.
The prevalence of implant biological complications has grown enormously over the last decade, in concordance with the impact of biofilm and its byproducts upon disease development. Deleterious habits and systemic conditions have been regarded as risk factors for peri-implantitis. However, little is known about the influence of local confounders upon the onset and progression of the disease. The present narrative review therefore describes the emerging local predisposing factors that place dental implants/patients at risk of developing peri-implantitis. A review is also made of the triggering factors capable of inducing peri-implantitis and of the accelerating factors capable of interfering with the progression of the disease. Full article
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Open AccessReview
Etiology and Measurement of Peri-Implant Crestal Bone Loss (CBL)
J. Clin. Med. 2019, 8(2), 166; https://doi.org/10.3390/jcm8020166
Received: 31 December 2018 / Revised: 22 January 2019 / Accepted: 24 January 2019 / Published: 1 February 2019
Cited by 1 | PDF Full-text (2005 KB) | HTML Full-text | XML Full-text
Abstract
The etiology of peri-implant crestal bone loss is today better understood and certain factors proposed in the past have turned out to not be of concern. Regardless, the incidence of crestal bone loss remains higher than necessary and this paper reviews current theory [...] Read more.
The etiology of peri-implant crestal bone loss is today better understood and certain factors proposed in the past have turned out to not be of concern. Regardless, the incidence of crestal bone loss remains higher than necessary and this paper reviews current theory on the etiology with a special emphasis on traditional and innovative methods to assess the level of crestal bone around dental implants that will enable greater sensitivity and specificity and significantly reduce variability in bone loss measurement. Full article
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Open AccessReview
Coupling between Osseointegration and Mechanotransduction to Maintain Foreign Body Equilibrium in the Long-Term: A Comprehensive Overview
J. Clin. Med. 2019, 8(2), 139; https://doi.org/10.3390/jcm8020139
Received: 10 December 2018 / Revised: 22 January 2019 / Accepted: 22 January 2019 / Published: 25 January 2019
Cited by 1 | PDF Full-text (327 KB) | HTML Full-text | XML Full-text
Abstract
The permanent interaction between bone tissue and the immune system shows us the complex biology of the tissue in which we insert oral implants. At the same time, new knowledge in relation to the interaction of materials and the host, reveals to us [...] Read more.
The permanent interaction between bone tissue and the immune system shows us the complex biology of the tissue in which we insert oral implants. At the same time, new knowledge in relation to the interaction of materials and the host, reveals to us the true nature of osseointegration. So, to achieve clinical success or perhaps most importantly, to understand why we sometimes fail, the study of oral implantology should consider the following advice equally important: a correct clinical protocol, the study of the immunomodulatory capacity of the device and the osteoimmunobiology of the host. Although osseointegration may seem adequate from the clinical point of view, a deeper vision shows us that a Foreign Body Equilibrium could be susceptible to environmental conditions. This is why maintaining this cellular balance should become our therapeutic target and, more specifically, the understanding of the main cell involved, the macrophage. The advent of new information, the development of new implant surfaces and the introduction of new therapeutic proposals such as therapeutic mechanotransduction, will allow us to maintain a healthy host-implant relationship long-term. Full article
Open AccessFeature PaperReview
Ligature-Induced Experimental Peri-Implantitis—A Systematic Review
J. Clin. Med. 2018, 7(12), 492; https://doi.org/10.3390/jcm7120492
Received: 4 November 2018 / Revised: 24 November 2018 / Accepted: 26 November 2018 / Published: 28 November 2018
PDF Full-text (459 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
This systematic review sought to analyze different experimental peri-implantitis models, their potential to induce marginal bone resorption (MBR) and the necessity of bacteria for bone loss to occur in these models. An electronic search in PubMed/Medline, Web of Science, and ScienceDirect was undertaken. [...] Read more.
This systematic review sought to analyze different experimental peri-implantitis models, their potential to induce marginal bone resorption (MBR) and the necessity of bacteria for bone loss to occur in these models. An electronic search in PubMed/Medline, Web of Science, and ScienceDirect was undertaken. A total of 133 studies were analyzed. Most studies induced peri-implantitis with ligatures that had formed a biofilm, sometimes in combination with inoculation of specific bacteria but never in a sterile environment. Most vertical MBR resulted from new ligatures periodically packed above old ones, followed by periodically exchanged ligatures and ligatures that were not exchanged. Cotton ligatures produced the most MBR, followed by steel, “dental floss” (not further specified in the studies) and silk. The amount of MBR varied significantly between different animal types and implant surfaces. None of the analyzed ligature studies aimed to validate that bacteria are necessary for the inducement of MBR. It cannot be excluded that bone loss can be achieved by other factors of the model, such as an immunological reaction to the ligature itself or trauma from repeated ligature insertions. Because all the included trials allowed plaque accumulation on the ligatures, bone resorbing capacity due to other factors could not be excluded or evaluated here. Full article
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