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Bacterial Biofilm Formation on Resorbing Magnesium Implants  [PDF]
Olga Charyeva, Jessica Neilands, Gunnel Svens?ter, Ann Wennerberg
Open Journal of Medical Microbiology (OJMM) , 2015, DOI: 10.4236/ojmm.2015.51001
Abstract: Background: Implant-associated infections are a result of bacterial adhesion to an implant surface and subsequent biofilm formation at the implantation site. This study compares different magnesium materials based on their ability to resist bacterial adhesion as well as further biofilm formation. Material and Methods: The surfaces of four magnesium-based materials (Mg2Ag, Mg10Gd, WE43 and 99.99% pure Mg) were characterized using atomic force microscope. In addition, the samples were tested for their ability to resist biofilm formation. Planktonic bacteria of either S. epidermidis or E. faecalis were allowed to adhere to the magnesium surfaces for two hour followed by rinsing and, for S. epidermidis, further incubation of 24, 72 and 168 h was carried out. Results: E. faecalis had a significantly stronger adhesion to all magnesium surfaces compared to S. epidermidis (p = 0.001). Biofilm growth of S. epidermidis was different on various magnesium materials: the amount of bacteria increased up to 72 h but interestingly a significant decrease was seen at 168 h on Mg2Ag and WE43 surfaces. For pure Mg and Mg10Gd the biofilm formation reached plateau at 72 h. Surface characteristics of resorbable magnesium materials were changing over time, and the surface was generally less rough at 168 h compared to earlier time points. No correlation was found between the surface topology and the amount of adherent bacteria. Conclusion: In early stages of biofilm adhesion, no differences between magnesium materials were observed. However, after 72 h Mg2Ag and WE43 had the best ability to suppress S. epidermidis’ biofilm formation. Also, bacterial adhesion to magnesium materials was not dependent on samples’ surface topology.
Flapless versus Conventional Flapped Dental Implant Surgery: A Meta-Analysis
Bruno Ramos Chrcanovic, Tomas Albrektsson, Ann Wennerberg
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0100624
Abstract: The aim of this study was to test the null hypothesis of no difference in the implant failure rates, postoperative infection, and marginal bone loss for patients being rehabilitated by dental implants being inserted by a flapless surgical procedure versus the open flap technique, against the alternative hypothesis of a difference. An electronic search without time or language restrictions was undertaken in March 2014. Eligibility criteria included clinical human studies, either randomized or not. The search strategy resulted in 23 publications. The I2 statistic was used to express the percentage of the total variation across studies due to heterogeneity. The inverse variance method was used for random-effects model or fixed-effects model, when indicated. The estimates of relative effect were expressed in risk ratio (RR) and mean difference (MD) in millimeters. Sixteen studies were judged to be at high risk of bias, whereas two studies were considered of moderate risk of bias, and five studies of low risk of bias. The funnel plots indicated absence of publication bias for the three outcomes analyzed. The test for overall effect showed that the difference between the procedures (flapless vs. open flap surgery) significantly affect the implant failure rates (P = 0.03), with a RR of 1.75 (95% CI 1.07–2.86). However, a sensitivity analysis revealed differences when studies of high and low risk of bias were pooled separately. Thus, the results must be interpreted carefully. No apparent significant effects of flapless technique on the occurrence of postoperative infection (P = 0.96; RR 0.96, 95% CI 0.23–4.03) or on the marginal bone loss (P = 0.16; MD ?0.07 mm, 95% CI ?0.16–0.03) were observed.
Novel Implant Coating Agent Promotes Gene Expression of Osteogenic Markers in Rats during Early Osseointegration
Kostas Bougas,Ryo Jimbo,Ying Xue,Kamal Mustafa,Ann Wennerberg
International Journal of Biomaterials , 2012, DOI: 10.1155/2012/579274
Abstract: The aim of this study was to evaluate the early bone response around laminin-1-coated titanium implants. Forty-five rats distributed in three equally sized groups were provided with one control (turned) and one test (laminin-1-coated) implant and were sacrificed after 3, 7, and 21 days. Real-time reverse-transcriptase polymerase chain reaction was performed for osteoblast markers (alkaline phosphatase, runt-related transcription factor 2, osteocalcin, type I collagen, and bone morphogenic protein 2), osteoclast markers (cathepsin K and tartrate-resistant acid phosphatase), inflammation markers (tumor necrosis factor α, interleukin 1β and interleukin 10), and integrin β1. Bone implant contact (BIC) and bone area (BA) were assessed and compared to the gene expression. After 3 days, the expression of bone markers was higher for the control group. After 7 days, the expression of integrin β1 and osteogenic markers was enhanced for the test group, while cathepsin K and inflammation markers were down-regulated. No significant differences in BIC or BA were detected between test and control at any time point. As a conclusion, implant coating with laminin-1 altered gene expression in the bone-implant interface. However, traditional evaluation methods, as histomorphometry, were not adequately sensitive to detect such changes due to the short follow-up time. 1. Introduction Dental implants have been proven to be a reliable long-term therapy against edentulism [1–3]. However, the reported high success figures of implant therapy have been based on implants inserted using two-stage surgical protocol and conventional loading. The increased demand on implant performance and the broadened treatment indications have led to the development of new moderately rough surfaces. Alterations in both the surface chemistry and topography may contribute to chemical influence on bone tissue, a phenomenon defined as bioactivity [4]. Furthermore, other factors such as surface energy, surface wettability, cellular maturation state, nutrition status, and microstresses alter the degree of bioactivity too. Compared to the previously used turned implants, the bioactively modified implants have demonstrated higher success rate in demanding cases, for example, early functional loading [5], one-stage surgery [6], and reconstructive jaw surgery [7]. When moderately rough surfaces remain within bone tissue no differences on microbial colonization are observed as compared to minimally rough surfaces [8]. However, there has been increasing evidence pointing out that as soon moderately rough
Surgical Protocol and Short-Term Clinical Outcome of Immediate Placement in Molar Extraction Sockets Using a Wide Body Implant
Stefan Vandeweghe,André Hattingh,Ann Wennerberg,Hugo De Bruyn
Journal of Oral & Maxillofacial Research , 2011,
Abstract: Objectives: Implant placement in molar extraction sockets can be difficult due to complex multi-root anatomy and the lack of predictable primary stability. The aim of this study was to evaluate the outcome of an 8 - 9 mm diameter tapered implant, designed to be placed in molar extraction sockets.Material and methods: Patients treated at least 1 year before with a Max implant (Southern Implants, Irene, South Africa) were invited for a clinical examination. Variables collected were surgical and prosthetic protocol, implant dimension and smoking habits. Peri-implant bone level was determined on peri-apical radiographs and compared to baseline, being implant insertion.Results: 98 implants had been placed in 89 patients. One implant had failed. Thirty eight patients representing 47 implants (maxilla 26, mandible 21) were available for clinical examination. Mean bone loss was 0.38 mm (SD 0.48; range - 0.50 – 1.95) after a mean follow-up of 20 months (range 12 - 35). Implant success was 97.9%. Around 30 implants, a bone substitute was used to fill the residual space, but this did not affect the bone loss outcome. Bone loss was only significantly different between maxilla and mandible (0.48 mm vs. 0.27 mm) and between the 8 and 9 mm diameter implants (0.23 mm vs. 0.55 mm). A full papilla was present at 71% of the interproximal sites and irrespective of bone loss.Conclusions: The Max implant demonstrated good primary stability, when placed in molar extraction sockets, with limited bone loss over time.
In vitro Evaluation of Calcium Phosphate Precipitation on Possibly Bioactive Titanium Surfaces in the Presence of Laminin
Kostas Bougas,Victoria Franke Stenport,Fredrik Currie,Ann Wennerberg
Journal of Oral & Maxillofacial Research , 2011,
Abstract: Objectives: The aim of the present study was to evaluate calcium phosphate precipitation and the amount of precipitated protein on three potentially bioactive surfaces when adding laminin in simulated body fluid.Material and Methods: Blasted titanium discs were prepared by three different techniques claimed to provide bioactivity: alkali and heat treatment (AH), anodic oxidation (AO) or hydroxyapatite coating (HA). A blasted surface incubated in laminin-containing simulated body fuid served as a positive control (B) while a blasted surface incubated in non laminin-containing simulated body fuid served as a negative control (B-). The immersion time was 1 hour, 24 hours, 72 hours and 1 week. Surface topography was investigated by interferometry and morphology by Scanning Electron Microscopy (SEM). Analysis of the precipitated calcium and phosphorous was performed by Energy Dispersive X-ray Spectroscopy (EDX) and the adsorbed laminin was quantified by iodine (125I) labeling.Results: SEM demonstrated that all specimens except for the negative control were totally covered with calcium phosphate (CaP) after 1 week. EDX revealed that B- demonstrated lower sum of Ca and P levels compared to the other groups after 1 week. Iodine labeling demonstrated that laminin precipitated in a similar manner on the possibly bioactive surfaces as on the positive control surface.Conclusions: Our results indicate that laminin precipitates equally on all tested titanium surfaces and may function as a nucleation center thus locally elevating the calcium concentration. Nevertheless further studies are required to clarify the role of laminin in the interaction of biomaterials with the host bone tissue.
The influence of surface treatment on the implant roughness pattern
Rosa, Marcio Borges;Albrektsson, Tomas;Francischone, Carlos Eduardo;Schwartz Filho, Humberto Osvaldo;Wennerberg, Ann;
Journal of Applied Oral Science , 2012, DOI: 10.1590/S1678-77572012000500010
Abstract: an important parameter for the clinical success of dental implants is the formation of direct contact between the implant and surrounding bone, whose quality is directly influenced by the implant surface roughness. a screw-shaped design and a surface with an average roughness of sa of 1-2 μm showed a better result. the combination of blasting and etching has been a commonly used surface treatment technique. the versatility of this type of treatment allows for a wide variation in the procedures in order to obtain the desired roughness. objectives: to compare the roughness values and morphological characteristics of 04 brands of implants, using the same type of surface treatment. in addition, to compare the results among brands, in order to assess whether the type of treatment determines the values and the characteristics of implant surface roughness. material and methods: three implants were purchased directly from each selected company in the market, i.e., 03 brazilian companies (biomet 3i of brazil, neodent and titaniumfix) and 01 korean company (oneplant). the quantitative or numerical characterization of the roughness was performed using an interferometer. the qualitative analysis of the surface topography obtained with the treatment was analyzed using scanning electron microscopy images. results: the evaluated implants showed a significant variation in roughness values: sa for oneplant was 1.01 μm; titaniumfix reached 0.90 μm; implants from neodent 0.67 μm, and biomet 3i of brazil 0.53 μm. moreover, the sem images showed very different patterns for the surfaces examined. concclusions: the surface treatment alone is not able to determine the roughness values and characteristics.
Characteristics of 2 Different Commercially Available Implants with or without Nanotopography
Ali Alenezi,Yoshihito Naito,Martin Andersson,Bruno R. Chrcanovic,Ann Wennerberg,Ryo Jimbo
International Journal of Dentistry , 2013, DOI: 10.1155/2013/769768
Abstract: The aim of this study was to assess histologically and histomorphometrically the early bone forming properties after 3 weeks for 2 commercially available implants, one supposedly possessing nanotopography and one without, in a rabbit femur model. Twenty-four implants divided equally into 2 groups were utilized in this study. The first group (P-I MICRO+NANO) was a titanium oxide (TiO2) microblasted and noble gas ion bombarded surface while the second group (Ospol) was anodic oxidized surface with calcium and phosphate incorporation. The implants were placed in the rabbit femur unicortically and were allowed to heal for 3 weeks. After euthanasia, the samples were subjected to histologic sectioning and bone-implant contact and bone area were evaluated histomorphometrically under an optical microscope. The histomorphometric evaluation presented that the P-I MICRO+NANO implants demonstrated significantly higher new bone formation as compared to the Ospol implants. Within the limitations of this study, the results suggested that nanostructures presented significantly higher bone formation after 3 weeks in vivo, and the effect of chemistry was limited, which is indicative that nanotopography is effective at early healing periods. 1. Introduction Replacing a missing tooth with endosseous implants has been recognized as a long-term successful treatment option [1, 2]. Recent research trends further focus on enhancing the bone in apposition to the implant to ensure rapid and firm osseointegration. The major factors influencing the bone response around implants are reported to be the implant macrodesign, surface topography, and surface chemistry, which have been investigated in numerous studies [3–5]. Surface topography in particular has drawn significant attention as an important factor since it has been suggested that moderately rough implant surfaces present the strongest bone responses [6–8]. Alteration of the surface topography can be conducted in various methods, which provide unique characteristics [9]. Roughening the surface with blasting particles along with different types of acid etching is a commonly utilized technique to modify the surface topography [10, 11]. This method is unique in a way that the roughness can be altered in a controlled manner by changing the velocity, particle size, and particle properties [12]. Furthermore, the acid etching not only cleans off the remnants of the particles, but creates a unique surface topography, which has also been reported to alter the surface chemistry [13, 14]. It has been presented in numerous in vivo
Effect of nanoporous TiO2 coating and anodized Ca2+ modification of titanium surfaces on early microbial biofilm formation
Victoria Fr?jd, Paula Linderb?ck, Ann Wennerberg, Luis Chávez de Paz, Gunnel Svens?ter, Julia R Davies
BMC Oral Health , 2011, DOI: 10.1186/1472-6831-11-8
Abstract: We have investigated how the properties of surfaces that may be used on abutments: turned titanium, sol-gel nanoporous TiO2 coated surfaces and anodized Ca2+ modified surfaces, affect biofilm formation by two early colonizers of the oral cavity: Streptococcus sanguinis and Actinomyces naeslundii. The bacteria were detected using 16S rRNA fluorescence in situ hybridization together with confocal laser scanning microscopy.Interferometry and atomic force microscopy revealed all the surfaces to be smooth (Sa ≤ 0.22 μm). Incubation with a consortium of S. sanguinis and A. naeslundii showed no differences in adhesion between the surfaces over 2 hours. After 14 hours, the level of biofilm growth was low and again, no differences between the surfaces were seen. The presence of saliva increased the biofilm biovolume of S. sanguinis and A. naeslundii ten-fold compared to when saliva was absent and this was due to increased adhesion rather than biofilm growth.Nano-topographical modification of smooth titanium surfaces had no effect on adhesion or early biofilm formation by S. sanguinis and A. naeslundii as compared to turned surfaces or those treated with anodic oxidation in the presence of Ca2+. The presence of saliva led to a significantly greater biofilm biovolume but no significant differences were seen between the test surfaces. These data thus suggest that modification with sol-gel derived nanoporous TiO2, which has been shown to improve osseointegration and soft-tissue healing in vivo, does not cause greater biofilm formation by the two oral commensal species tested than the other surfaces.Titanium dental implants are commonly used to replace lost teeth and much work has been focused on the optimization of the physico-chemical and mechanical properties of implant materials to improve their integration with host bone and soft-tissues. The soft tissue barrier around dental implants serves as a protective seal between the oral environment and the underlying peri-implant bo
The Effect of Laminin-1-Doped Nanoroughened Implant Surfaces: Gene Expression and Morphological Evaluation
Humberto Osvaldo Schwartz-Filho,Kostas Bougas,Paulo G. Coelho,Ying Xue,Mariko Hayashi,Rafael Silveira Faeda,Rosemary Adriana Chiérici Marcantonio,Daisuke Ono,Fumio Kobayashi,Kamal Mustafa,Ann Wennerberg,Ryo Jimbo
International Journal of Biomaterials , 2012, DOI: 10.1155/2012/305638
Abstract: Aim. This study aimed to observe the morphological and molecular effect of laminin-1 doping to nanostructured implant surfaces in a rabbit model. Materials and Methods. Nanostructured implants were coated with laminin-1 (test; dilution, 100?μg/mL) and inserted into the rabbit tibiae. Noncoated implants were used as controls. After 2 weeks of healing, the implants were removed and subjected to morphological analysis using scanning electron microscopy (SEM) and gene expression analysis using the real-time reverse transcriptase-polymerase chain reaction (RT-PCR). Results. SEM revealed bony tissue attachment for both control and test implants. Real-time RT-PCR analysis showed that the expression of osteoblast markers RUNX-2, osteocalcin, alkaline phosphatase, and collagen I was higher (1.62-fold, 1.53-fold, 1.97-fold, and 1.04-fold, resp.) for the implants modified by laminin-1 relative to the control. All osteoclast markers investigated in the study presented higher expression on the test implants than controls as follows: tartrate-resistant acid phosphatase (1.67-fold), calcitonin receptor (1.35-fold), and ATPase (1.25-fold). The test implants demonstrated higher expression of inflammatory markers interleukin-10 (1.53-fold) and tumour necrosis factor-α (1.61-fold) relative to controls. Conclusion. The protein-doped surface showed higher gene expression of typical genes involved in the osseointegration cascade than the control surface. 1. Introduction The osseointegration cascade begins immediately after the implant is placed in the bone, where the blood contiguously interacts with the implant surface. Irrespective of the biomaterial, surface topography, or wettability status of the surface, the initial contact with blood will rapidly attract proteins [1], which in turn will initiate the process of bone formation [2, 3]. In fact, protein adsorption to the implant surface has been suggested to be important for the osteoconduction stage of osseointegration [4–6]. Studies have also investigated the significance of the protein-implant interaction phenomenon [7–9], in which some proteins significantly enhance migration, attachment, proliferation, and differentiation at the implant surface [8]. Protein adsorption to biomaterials is intriguing since one specific protein never remains in a single niche for extended periods of time and constantly undergoes alterations depending on its molecular weight [10]. The so-called “Vroman effect” is an indication that proteins play different roles in biological reactions. For example, the effect of plasma fibronectin has
Current knowledge about the hydrophilic and nanostructured SLActive surface
Wennerberg A, Galli S, Albrektsson T
Clinical, Cosmetic and Investigational Dentistry , 2011, DOI: http://dx.doi.org/10.2147/CCIDE.S15949
Abstract: rrent knowledge about the hydrophilic and nanostructured SLActive surface Review (3258) Total Article Views Authors: Wennerberg A, Galli S, Albrektsson T Published Date September 2011 Volume 2011:3 Pages 59 - 67 DOI: http://dx.doi.org/10.2147/CCIDE.S15949 Ann Wennerberg1,2, Silvia Galli2, Tomas Albrektsson2,3 1Department of Prosthodontics, Malm University, Malm , 2Department of Biomaterials, Gothenburg University, Gothenburg, 3Department of Materials Science and Technology, Malm University, Sweden Abstract: This review summarizes the present documentation for the SLActive surface, a hydrophilic and nanostructured surface produced by Straumann Company in Switzerland, and covers the results from 15 in vitro, 17 in vivo, and 16 clinical studies. The SLActive surface is a development of the large grit-blasted and acid-etched SLA surface, and is further processed to a high degree of hydrophilicity. In general, the in vitro and in vivo studies of the SLActive surface demonstrate a stronger cell and bone tissue response than for the predecessor, the SLA surface, produced by the same company. However, in most studies, this difference disappears after 6–8 weeks. In the clinical studies, a stronger bone response was reported for the SLActive surface during the early healing phase when compared with the SLA surface. However, the later biological response was quite similar for the two surfaces and both demonstrated very good clinical results.
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