| 1. |
- Campos, Felipe E. B., et al.
(författare)
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Are insertion torque and early osseointegration proportional? : A histologicevaluation
- 2015
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Ingår i: Clinical Oral Implants Research. - : John Wiley & Sons. - 0905-7161 .- 1600-0501. ; 26:11, s. 1256-1260
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Tidskriftsartikel (refereegranskat)abstract
- ObjectivesThe objective of this histologic study was to determine the effect of three drilling protocols (oversized, intermediate, and undersized) on biologic responses to a single implant type at early healing periods (2weeks in vivo) in a beagle dog model. Materials and methodsTen beagle dogs were acquired and subjected to surgeries in the tibia 2weeks before euthanasia. During surgery, each dog received three Unitite implants, 4mm in diameter by 10mm in length, in bone sites drilled to 3.5, 3.75, and 4.0mm in final diameter. The insertion torque was recorded during surgery, and bone-to-implant contact (BIC), and bone area fraction occupied (BAFO) measured from the histology. Each outcome measure was compared between treatment conditions with the Wilcoxon signed-rank test. Bonferroni-corrected statistical significance was set to 95%. ResultsInsertion torque increased as an inverse function of drilling diameter, as indicated by significant differences in torque levels between each pair of conditions (P=0.005). BIC and BAFO levels were highest and statistically similar in the recommended and undersized conditions and significantly reduced in the oversized condition (P<0.01). ConclusionsReduced drilling dimensions resulted in increased insertion torque (primary stability). While BIC and BAFO were maximized when drilling the recommended diameter hole, only the oversized hole resulted in evidence of statistically reduced integration.
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| 2. |
- Coelho, Paulo G, et al.
(författare)
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Alveolar buccal bone maintenance after immediate implantation with a surgical flap approach: a study in dogs.
- 2011
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Ingår i: The International journal of periodontics & restorative dentistry. - 0198-7569. ; 31:6
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Tidskriftsartikel (refereegranskat)abstract
- This study evaluated buccal bone maintenance after implantation with a surgical flap approach immediately following tooth extraction in a dog model. Mandibular premolars of six dogs were extracted, and threaded implants of 4-mm diameter and 8-mm length with as-machined and dual acid-etched surfaces were placed through balanced procedures in the distal root extraction sockets with a full-thickness flap design. Submerged healing was allowed for 4 weeks, and following euthanization, bone-to-implant contact and buccal and lingual bone loss were evaluated. None of the parameters evaluated were indicative of an effect of implant surface in hindering bone loss around immediately placed implants. (Int J Periodontics Restorative Dent 2011;31:e80-e86.).
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| 3. |
- Coelho, Paulo G, et al.
(författare)
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Effect of Si addition on Ca- and P-impregnated implant surfaces with nanometer-scale roughness: an experimental study in dogs.
- 2012
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Ingår i: Clinical oral implants research. - : Wiley. - 1600-0501 .- 0905-7161.
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: To investigate the effect of Si addition on a nanometer-scale roughness Ca and P implant surfaces in a canine tibia model by biomechanical and histomorphometric evaluations. Material and methods: The implant surfaces comprised a resorbable media CaP microblasted (control) and a CaP resorbable media+silica-boost microblasted (experimental) surfaces. Surfaces were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and optical interferometry (IFM) down to the nanometric level. The animal model involved the bilateral placement of control (n=24) and experimental surface (n=24) implants along the proximal tibiae of six dogs, remaining in vivo for 2 or 4 weeks. After euthanization, half of the specimens were torqued-to-interface failure, and the other half was subjected to histomorphologic and bone-to-implant contact (BIC) evaluation. Torque and BIC statistical evaluation was performed by the Friedman test at 95% level of significance, and comparisons between groups was performed by the Dunn test. Results: IFM and SEM observations depicted comparable roughness parameters for both implant surfaces on the micrometer and nanometer scales. XPS analysis revealed similar chemical composition, except for the addition of Si on the experimental group. Torque-to-interface failure and BIC mean values showed no significant differences (P=0.25 and 0.51, respectively) at both 2- and 4-week evaluation points for experimental and control groups. Early bone healing histomorphologic events were similar between groups. Conclusions: The experimental surface resulted in not significantly different biomechanical fixation and BIC relative to control. Both surfaces were biocompatible and osseoconductive. To cite this article: Coelho PG, Granato R, Marin C, Jimbo R, Lin S, Witek L, Suzuki M, Bonfante EA. Effect of Si addition on Ca- and P-impregnated implant surfaces with nanometer-scale roughness: an experimental study in dogs. Clin. Oral Impl. Res. xx, 2011; 000-000. doi: 10.1111/j.1600-0501.2010.02150.x.
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| 4. |
- Coelho, Paulo G., et al.
(författare)
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Microrobotized blasting improves the bone-to-textured implant response. A preclinical in vivo biomechanical study
- 2016
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Ingår i: Journal of The Mechanical Behavior of Biomedical Materials. - : Elsevier. - 1751-6161 .- 1878-0180. ; 56, s. 175-182
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Tidskriftsartikel (refereegranskat)abstract
- This study evaluated the effect of microrobotized blasting of titanium endosteal implants relative to their manually blasted counterparts. Two different implant systems were utilized presenting two different implant surfaces. Control surfaces (Manual) were fabricated by manually grit blasting the implant surfaces while experimental surfaces (Microblasted) were fabricated through a microrobotized system that provided a one pass grit blasting routine. Both surfaces were created with the same similar to 50 gm average particle size alumina powder at similar to 310 KPa. Surfaces were then etched with 37% HCl for 20 min, washed, and packaged through standard industry procedures. The surfaces were characterized through scanning electron microscopy (SEM) and optical interferometry, and were then placed in a beagle dog radius model remaining in vivo for 3 and 6 weeks. The implant removal torque was recorded and statistical analysis evaluated implant system and surface type torque levels as a function of time in vivo. Histologic sections were qualitatively evaluated for tissue response. Electron microscopy depicted textured surfaces for both manual and microblasted surfaces. Optical interferometry showed significantly higher S-a, S-q, values for the microblasted surface and no significant difference for S-ds and S-dr values between surfaces. In vivo results depicted that statistically significant gains in biomechanical fixation were obtained for both implant systems tested at 6 weeks in vivo, while only one system presented significant biomechanical gain at 3 weeks. Histologic sections showed qualitative higher amounts of new bone forming around microblasted implants relative to the manually blasted group. Microrobotized blasting resulted in higher biomechanical fixation of endosteal dental implants and should be considered as an alternative for impant surface manufacturing.
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| 5. |
- Coelho, Paulo G., et al.
(författare)
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Osseointegration : hierarchical designing encompassing the macrometer, micrometer, and nanometer length scales
- 2015
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Ingår i: Dental Materials. - : Elsevier. - 0109-5641 .- 1879-0097. ; 31:1, s. 37-52
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Tidskriftsartikel (refereegranskat)abstract
- Objective. Osseointegration has been a proven concept in implant dentistry and orthopedics for decades. Substantial efforts for engineering implants for reduced treatment time frames have focused on micrometer and most recently on nanometer length scale alterations with negligible attention devoted to the effect of both macrometer design alterations and surgical instrumentation on osseointegration. This manuscript revisits osseointegration addressing the individual and combined role of alterations on the macrometer, micrometer, and nanometer length scales on the basis of cell culture, preclinical in vivo studies, and clinical evidence. Methods. A critical appraisal of the literature was performed regarding the impact of dental implant designing on osseointegration. Results from studies with different methodological approaches and the commonly observed inconsistencies are discussed. Results. It is a consensus that implant surface topographical and chemical alterations can hasten osseointegration. However, the tailored combination between multiple length scale design parameters that provides maximal host response is yet to be determined. Signcance. In spite of the overabundant literature on osseointegration, a proportional inconsistency in findings hitherto encountered warrants a call for appropriate multivariable study designing to ensure that adequate data collection will enable osseointegration maximization and/or optimization, which will possibly lead to the engineering of endosteal implant designs that can be immediately placed/loaded regardless of patient dependent conditions.
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| 6. |
- Coelho, Paulo G., et al.
(författare)
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Osseointegration of Plateau Root Form Implants : Unique Healing Pathway Leading to Haversian-Like Long-Term Morphology
- 2015
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Ingår i: Engineering Mineralized and Load Bearing Tissue. - Cham : Springer. - 9783319223452 - 9783319223445 ; , s. 111-128
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Endosteal dental implants have been utilized as anchors for dental and orthopedic rehabilitations for decades with one of the highest treatment success rates in medicine. Such success is due to the phenomenon of osseointegration where after the implant surgical placement, bone healing results into an intimate contact between bone and implant surface. While osseointegration is an established phenomenon, the route which osseointegration occurs around endosteal implants is related to various implant design factors including surgical instrumentation and implant macro, micro, and nanometer scale geometry. In an implant system where void spaces (healing chambers) are present between the implant and bone immediately after placement, its inherent bone healing pathway results in unique opportunities to accelerate the osseointegration phenomenon at the short-term and its maintenance on the long-term through a haversian-like bone morphology and mechanical properties.
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| 7. |
- Coelho, Paulo G., et al.
(författare)
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Revisiting the Role of Implant Design and Surgical Instrumentation on Osseointegration
- 2017
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Ingår i: Implant Aesthetics. - Cham : Springer. - 9783319507040 - 9783319507064 ; , s. 43-56
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Bokkapitel (refereegranskat)abstract
- Osseointegration of metallic devices has shown to be successful in several biomedical fields. Despite the high success rates, continuous efforts to reduce osseointegration time have been marked by investigations considering a limited number of variables. Recent research has pointed that the interplay between surgical instrumentation and device macrogeometry not only plays a key role on both early and delayed stages of osseointegration but may also be key in how efficient smaller length scale designing (at the micro- and nanogeometrical levels) may be in hastening early stages of osseointegration. The present chapter focuses on how the different metallic device design length scales’ interplay (macro, micro, and nano) affects the bone response and how its understanding may affect the next generation of metallic device designing for osseointegration.
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| 8. |
- Gil, Luiz F., et al.
(författare)
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Progressive plateau root form dental implant osseointegration : a human retrieval study
- 2015
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Ingår i: Journal of Biomedical Materials Research. Part B - Applied biomaterials. - : John Wiley & Sons. - 1552-4973 .- 1552-4981. ; 103:6, s. 1328-1332
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Tidskriftsartikel (refereegranskat)abstract
- Although preclinical and sparse human histology retrieval studies have shown that the interface between implant and bone is constantly remodeling, no human retrieval database has been developed to determine the effect of functional loading time and other clinical/implant design variables on osseointegration. The present study tested the hypothesis that bone-to-implant contact (BIC) and bone area fraction occupancy (BAFO) increase over functional loading time around dental implants. Due to prosthetic retreatment reasons, 93 human implant retrievals from the same manufacturer (Bicon LLC, Boston, MA, USA) were obtained over a period of approximately 15 years. The retrieved implants were under functional loading from 120 days to approximate to 18 years and were histomorphologic/metrically evaluated. BIC/BAFO were assessed as a function of multiple independent variables: implant surface type, diameter, length, jaw (maxilla/mandible), region (anterior/posterior), and time of functional loading. The results showed that both BIC and BAFO increased over time independently of implant design/clinical variables, supporting the postulated hypothesis. (c) 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 103B: 1328-1332, 2015.
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| 9. |
- Granato, Rodrigo, et al.
(författare)
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Osteointegrative and microgeometric comparison between micro-blasted and alumina blasting/acid etching on grade II and V titanium alloys (Ti-6Al-4V).
- 2019
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Ingår i: Journal of The Mechanical Behavior of Biomedical Materials. - : Elsevier. - 1751-6161 .- 1878-0180. ; 97, s. 288-295
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Tidskriftsartikel (refereegranskat)abstract
- This study evaluated the effect of alumina-blasted/acid-etched (AB/AE) or microabrasive blasting (C3-Microblasted) surface treatment on the osseointegration of commercially-pure Ti (grade II) and Ti-6Al-4V alloy (grade V) implants compared to as-machined surfaces. Surface characterization was performed by scanning electron microscopy and optical interferometry (IFM) to determine roughness parameters (Sa and Sq, n=3 per group). One-hundred forty-four implants were placed in the radii of 12 beagle dogs, for histological (n=72, bone-to-implant contact - BIC and bone-area-fraction occupancy -BAFO) and torque to interface failure test at 3 and 6 weeks (n=72). SEM and IFM revealed a significant increase in surface texture for AB/AE and C3-Microblasted surfaces compared to machined surface, regardless of titanium substrate. Torque-to-interface failure test showed significant increase in values from as-machined to AB/AE and to C3-Microblasted. Considering time in vivo, alloy grade, and surface treatment, the C3-microblasted presented higher mean BIC values relative to AB/AE and machined surfaces for both alloy types. BAFO levels were significantly higher for both textured surfaces groups relative to the machined group at 3 weeks, but differences were not significant between the three surfaces for each alloy type at 6 weeks. Surface treatment resulted in roughness that improved osseointegration in Grade II and V titanium substrates.
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| 10. |
- Jimbo, Ryo, et al.
(författare)
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Regeneration of the cementum and periodontal ligament using local BDNF delivery in class II furcation defects
- 2018
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Ingår i: Journal of Biomedical Materials Research. Part B - Applied biomaterials. - : John Wiley & Sons. - 1552-4973 .- 1552-4981. ; 106:4, s. 1611-1617
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Tidskriftsartikel (refereegranskat)abstract
- Periodontal furcation defects are usually addressed by the placement of a physical barrier which may limit the regenerative potential of periodontal wounds. This study morphometrically quantified the regenerative effect of brain-derived neurotrophic factor (BDNF) in furcation defects in a non-human primate model. Grade II furcation defects (with and without induced inflammation prior to surgery) were created on the first and second molars of eight non-human primates. Defects were treated with open flap debridement and subsequently filled with either: Group A; BDNF (500 µg mL−1) in high-molecular weight-hyaluronic acid (HMW-HA), Group B; BDNF (50 µg mL−1) in HMW-HA, Group C; HMW-HA acid only, Group D; unfilled defect, or Group E; BDNF (500 µg mL−1) in saline. Periodontal wound healing was observed every 2 weeks by computed-tomography. At 11 weeks all animals were sacrificed and maxillary and mandibular block biopsies were referred for nondecalcified histology. Linear measurements of new cementum (cellular and acellular) and periodontal ligament (PDL) formation were performed. Computerized-tomography reconstruction and software quantification demonstrated successful bone fill for all groups. However, histometric assessment demonstrated significantly higher level of total periodontal regeneration for the 500 µg mL−1 BDNF HMW-HA relative to all other groups. No significant differences in cementogenesis were observed among groups. Significantly higher acellular cementum formation was observed for sites where inflammation was not induced prior to surgical procedures. While all groups experienced similar bone fill and cementogenesis, the 500 µg mL−1 BDNF HMW-HA appeared to most effectively repair PDL (minimum increase of ∼22% relative to all groups; over 200% relative to unfilled defects).
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