151
|
Shantavasinkul P, Akkus O, Palomo JM, Baumgaertel S. Surface strain distribution of orthodontic miniscrews under load. Am J Orthod Dentofacial Orthop 2016; 150:444-50. [DOI: 10.1016/j.ajodo.2016.02.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2015] [Revised: 02/01/2016] [Accepted: 02/01/2016] [Indexed: 11/16/2022]
|
152
|
Wu CC, Tsai YF, Hsu LH, Chen JP, Sumi S, Yang KC. A self-reinforcing biodegradable implant made of poly(ɛ-caprolactone)/calcium phosphate ceramic composite for craniomaxillofacial fracture fixation. J Craniomaxillofac Surg 2016; 44:1333-41. [DOI: 10.1016/j.jcms.2016.04.027] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Revised: 03/24/2016] [Accepted: 04/15/2016] [Indexed: 11/24/2022] Open
|
153
|
bin Kamisan MAA, Yokota K, Ueno T, Kinoshita H, Homma S, Yajima Y, Abe S, Takano N. Drilling force and speed for mandibular trabecular bone in oral implant surgery. BIOMATERIALS AND BIOMECHANICS IN BIOENGINEERING 2016. [DOI: 10.12989/bme.2016.3.1.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
|
154
|
Park HJ, Min KD, Lee MC, Kim SH, Lee OJ, Ju HW, Moon BM, Lee JM, Park YR, Kim DW, Jeong JY, Park CH. Fabrication of 3D porous SF/β-TCP hybrid scaffolds for bone tissue reconstruction. J Biomed Mater Res A 2016; 104:1779-87. [DOI: 10.1002/jbm.a.35711] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Revised: 02/27/2016] [Accepted: 03/04/2016] [Indexed: 11/10/2022]
Affiliation(s)
- Hyun Jung Park
- Nano-Bio Regenerative Medical Institute; Hallym University; Gangwon 200-702 Korea
| | - Kyung Dan Min
- Research and Development Institute, CGbio corporation; Seongnam Korea
| | - Min Chae Lee
- Nano-Bio Regenerative Medical Institute; Hallym University; Gangwon 200-702 Korea
| | - Soo Hyeon Kim
- Nano-Bio Regenerative Medical Institute; Hallym University; Gangwon 200-702 Korea
| | - Ok Joo Lee
- Nano-Bio Regenerative Medical Institute; Hallym University; Gangwon 200-702 Korea
| | - Hyung Woo Ju
- Nano-Bio Regenerative Medical Institute; Hallym University; Gangwon 200-702 Korea
| | - Bo Mi Moon
- Nano-Bio Regenerative Medical Institute; Hallym University; Gangwon 200-702 Korea
| | - Jung Min Lee
- Nano-Bio Regenerative Medical Institute; Hallym University; Gangwon 200-702 Korea
| | - Ye Ri Park
- Nano-Bio Regenerative Medical Institute; Hallym University; Gangwon 200-702 Korea
| | - Dong Wook Kim
- Nano-Bio Regenerative Medical Institute; Hallym University; Gangwon 200-702 Korea
| | - Ju Yeon Jeong
- Nano-Bio Regenerative Medical Institute; Hallym University; Gangwon 200-702 Korea
| | - Chan Hum Park
- Nano-Bio Regenerative Medical Institute; Hallym University; Gangwon 200-702 Korea
- Department of Otorhinolaryngology-Head and Neck Surgery; Chuncheon Sacred Heart Hospital, Hallym University College of Medicine; Gangwon 200-704 Korea
| |
Collapse
|
155
|
Raphel J, Karlsson J, Galli S, Wennerberg A, Lindsay C, Haugh MG, Pajarinen J, Goodman SB, Jimbo R, Andersson M, Heilshorn SC. Engineered protein coatings to improve the osseointegration of dental and orthopaedic implants. Biomaterials 2016; 83:269-82. [PMID: 26790146 PMCID: PMC4771523 DOI: 10.1016/j.biomaterials.2015.12.030] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Revised: 12/19/2015] [Accepted: 12/29/2015] [Indexed: 01/10/2023]
Abstract
Here we present the design of an engineered, elastin-like protein (ELP) that is chemically modified to enable stable coatings on the surfaces of titanium-based dental and orthopaedic implants by novel photocrosslinking and solution processing steps. The ELP includes an extended RGD sequence to confer bio-signaling and an elastin-like sequence for mechanical stability. ELP thin films were fabricated on cp-Ti and Ti6Al4V surfaces using scalable spin and dip coating processes with photoactive covalent crosslinking through a carbene insertion mechanism. The coatings withstood procedures mimicking dental screw and hip replacement stem implantations, a key metric for clinical translation. They promoted rapid adhesion of MG63 osteoblast-like cells, with over 80% adhesion after 24 h, compared to 38% adhesion on uncoated Ti6Al4V. MG63 cells produced significantly more mineralization on ELP coatings compared to uncoated Ti6Al4V. Human bone marrow mesenchymal stem cells (hMSCs) had an earlier increase in alkaline phosphatase activity, indicating more rapid osteogenic differentiation and mineral deposition on adhesive ELP coatings. Rat tibia and femur in vivo studies demonstrated that cell-adhesive ELP-coated implants increased bone-implant contact area and interfacial strength after one week. These results suggest that ELP coatings withstand surgical implantation and promote rapid osseointegration, enabling earlier implant loading and potentially preventing micromotion that leads to aseptic loosening and premature implant failure.
Collapse
Affiliation(s)
- Jordan Raphel
- Department of Materials Science and Engineering, Stanford University, Stanford, CA, USA
| | - Johan Karlsson
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Silvia Galli
- Department of Prosthodontics, Faculty of Odontology, Malmö University, Malmö, Sweden
| | - Ann Wennerberg
- Department of Prosthodontics, Faculty of Odontology, Malmö University, Malmö, Sweden
| | - Christopher Lindsay
- Department of Materials Science and Engineering, Stanford University, Stanford, CA, USA
| | - Matthew G Haugh
- Department of Materials Science and Engineering, Stanford University, Stanford, CA, USA
| | - Jukka Pajarinen
- Department of Orthopaedic Surgery, Stanford University, Stanford, CA, USA
| | - Stuart B Goodman
- Department of Orthopaedic Surgery, Stanford University, Stanford, CA, USA
| | - Ryo Jimbo
- Department of Prosthodontics, Faculty of Odontology, Malmö University, Malmö, Sweden; Department of Oral and Maxillofacial Surgery and Oral Medicine, Faculty of Odontology, Malmö University, Malmö, Sweden
| | - Martin Andersson
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Sarah C Heilshorn
- Department of Materials Science and Engineering, Stanford University, Stanford, CA, USA.
| |
Collapse
|
156
|
Idaszek J, Bruinink A, Święszkowski W. Delayed degradation of poly(lactide-co-glycolide) accelerates hydrolysis of poly(ε-caprolactone) in ternary composite scaffolds. Polym Degrad Stab 2016. [DOI: 10.1016/j.polymdegradstab.2015.12.020] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
|
157
|
Martorelli M, Maietta S, Gloria A, De Santis R, Pei E, Lanzotti A. Design and Analysis of 3D Customized Models of a Human Mandible. ACTA ACUST UNITED AC 2016. [DOI: 10.1016/j.procir.2015.11.016] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
158
|
Toro-Ibacache V, Fitton LC, Fagan MJ, O'Higgins P. Validity and sensitivity of a human cranial finite element model: implications for comparative studies of biting performance. J Anat 2015; 228:70-84. [PMID: 26398104 DOI: 10.1111/joa.12384] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/24/2015] [Indexed: 11/28/2022] Open
Abstract
Finite element analysis (FEA) is a modelling technique increasingly used in anatomical studies investigating skeletal form and function. In the case of the cranium this approach has been applied to both living and fossil taxa to (for example) investigate how form relates to function or infer diet or behaviour. However, FE models of complex musculoskeletal structures always rely on simplified representations because it is impossible completely to image and represent every detail of skeletal morphology, variations in material properties and the complexities of loading at all spatial and temporal scales. The effects of necessary simplifications merit investigation. To this end, this study focuses on one aspect, model geometry, which is particularly pertinent to fossil material where taphonomic processes often destroy the finer details of anatomy or in models built from clinical CTs where the resolution is limited and anatomical details are lost. We manipulated the details of a finite element (FE) model of an adult human male cranium and examined the impact on model performance. First, using digital speckle interferometry, we directly measured strains from the infraorbital region and frontal process of the maxilla of the physical cranium under simplified loading conditions, simulating incisor biting. These measured strains were then compared with predicted values from FE models with simplified geometries that included modifications to model resolution, and how cancellous bone and the thin bones of the circum-nasal and maxillary regions were represented. Distributions of regions of relatively high and low principal strains and principal strain vector magnitudes and directions, predicted by the most detailed FE model, are generally similar to those achieved in vitro. Representing cancellous bone as solid cortical bone lowers strain magnitudes substantially but the mode of deformation of the FE model is relatively constant. In contrast, omitting thin plates of bone in the circum-nasal region affects both mode and magnitude of deformation. Our findings provide a useful frame of reference with regard to the effects of simplifications on the performance of FE models of the cranium and call for caution in the interpretation and comparison of FEA results.
Collapse
Affiliation(s)
- Viviana Toro-Ibacache
- Centre for Anatomical and Human Sciences, Department of Archaeology and Hull York Medical School, University of York, Heslington, York, UK.,Facultad de Odontología, Universidad de Chile, Independencia, Región Metropolitana, Chile
| | - Laura C Fitton
- Centre for Anatomical and Human Sciences, Department of Archaeology and Hull York Medical School, University of York, Heslington, York, UK
| | - Michael J Fagan
- School of Engineering, Medical and Biological Engineering Research Group, University of Hull, Hull, UK
| | - Paul O'Higgins
- Centre for Anatomical and Human Sciences, Department of Archaeology and Hull York Medical School, University of York, Heslington, York, UK
| |
Collapse
|
159
|
Guo M, Li X. Development of porous Ti6Al4V/chitosan sponge composite scaffold for orthopedic applications. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2015; 58:1177-81. [PMID: 26478418 DOI: 10.1016/j.msec.2015.09.061] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Revised: 08/21/2015] [Accepted: 09/14/2015] [Indexed: 12/18/2022]
Abstract
A novel composite scaffold consisting of porous Ti6Al4V part filled with chitosan sponge was fabricated using a combination of electron beam melting and freeze-drying. The mechanical properties of porous Ti6Al4V part were examined via compressive test. The ultimate compressive strength was 85.35 ± 8.68 MPa and the compressive modulus was 2.26 ± 0.42 GPa. The microstructure of composite scaffold was characterized using scanning electron microscopy. The chitosan sponge filled in Ti6Al4V part exhibited highly porous and well-interconnected micro-pore architecture. The osteoblastic cells were seeded on scaffolds to test their seeding efficiency and biocompatibility. Significantly higher cell seeding efficiency was found on composite scaffold. The biological response of osteoblasts on composite scaffolds was superior in terms of improved cell attachment, higher proliferation, and well-spread morphology in relation to porous Ti6Al4V part. These results suggest that the Ti6Al4V/chitosan composite scaffold is potentially useful as a biomedical scaffold for orthopedic applications.
Collapse
Affiliation(s)
- Miao Guo
- College of Life Information Science & Instrument Engineering, Hangzhou Dianzi University, Hangzhou 310018, China
| | - Xiang Li
- School of Mechanical Engineering, Shanghai Jiao Tong University, State Key Laboratory of Mechanical System and Vibration, Shanghai 200240, China.
| |
Collapse
|
160
|
Garitaonaindia U, Alcaraz JL. Influence of a micro-thread at cervical position and a cylindrical intermediate zone on the mechanical behaviour of dental implants: A three-dimensional finite element analysis. Proc Inst Mech Eng H 2015; 229:670-80. [PMID: 26334036 DOI: 10.1177/0954411915598175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The purpose of this work is to analyse the influence on the biomechanical behaviour of dental implants of a micro-thread at their cervical part as well as of a cylindrical geometry at an intermediate zone. Stresses and strains in the elements involved, that is, bone, implant, screw and abutment, have to be considered in detail. Three different three-dimensional finite element models are generated to analyse the behaviour of the various components under the so-called tightening and operating conditions. For the modelling, material specifications for the cancellous bone and cortical bone, on one hand, and titanium properties for the implant, screw and abutment, on the other, are implemented. The tightening condition was fixed according to the stresses in the screw. The operating conditions were simulated by applying a force of 150 N, taking into account ISO 14801:2007 standard. The maximum stress under tightening conditions occurs always in the screw, while under operating conditions it is produced at the screw or the abutment, although considerable stress values are also present in the implant. In all the models, the maximum stress at the junction between the implant and the bone occurs within the cortical bone. Implants provided with micro-thread at the cervical position are advantageous over homogeneously threaded implants since lower stresses in both the implant and the adjacent bone are produced. A cylindrical intermediate portion on the implant surface does not present special advantage over the implants with continuous external thread under tightening and operating conditions.
Collapse
Affiliation(s)
- Ugutz Garitaonaindia
- Department of Mechanical Engineering, Eskola Politeknikoa - Donostia, University of the Basque Country, San Sebastián, Spain
| | - José Luis Alcaraz
- Department of Mechanical Engineering, Eskola Politeknikoa - Donostia, University of the Basque Country, San Sebastián, Spain
| |
Collapse
|
161
|
Huo J, Dérand P, Rännar LE, Hirsch JM, Gamstedt EK. Failure location prediction by finite element analysis for an additive manufactured mandible implant. Med Eng Phys 2015; 37:862-9. [DOI: 10.1016/j.medengphy.2015.06.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Revised: 05/13/2015] [Accepted: 06/09/2015] [Indexed: 11/24/2022]
|
162
|
Distraction Osteogenesis Using Bone Matrix Osteotensors in Ectodermal Dysplasia: A Case Report. IMPLANT DENT 2015; 24:612-9. [PMID: 26317574 DOI: 10.1097/id.0000000000000310] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
INTRODUCTION Ectodermal dysplasia patients require complex oral rehabilitation. Bone matrix Osteotensors activate the patient's own stem cells to promote new bone formation through an autogenous growth factor cascade generated by a targeted flapless bone distraction before implant and/or bone graft therapy. MATERIALS AND METHODS The maxillary and mandibular bone were activated 21 (for type I bone) to 45 days (for type IV bone) before implant and/or bone substitute installation. Purpose-designed Osteotensors initiated massive recruitment of stem cells in the intended bone recipient site, thereby triggering neoangiogenesis and osteogenesis. After new bone formation, root-form implants and Diskimplants were installed. Functional loading was obtained at 48 hours using highly rigid, screw-secured fixed upper and lower full-arch prostheses. RESULTS At 3 years, all implants appeared clinically and radiologically osseointegrated with an excellent functional and esthetic outcome. CONCLUSION Flapless distraction osteogenesis using bone matrix Osteotensors several weeks before surgery improved the initial quality and volume of the recipient bone bed. This minimally invasive approach allows future successful immediate implant-supported complete maxillomandibular fixed rehabilitation without preliminary grafting procedures in patients with an unfavorable initial bone anatomy.
Collapse
|
163
|
Boukari Y, Scurr DJ, Qutachi O, Morris AP, Doughty SW, Rahman CV, Billa N. Physicomechanical properties of sintered scaffolds formed from porous and protein-loaded poly(DL-lactic-co-glycolic acid) microspheres for potential use in bone tissue engineering. JOURNAL OF BIOMATERIALS SCIENCE-POLYMER EDITION 2015; 26:796-811. [DOI: 10.1080/09205063.2015.1058696] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
164
|
Omori M, Tsuchiya S, Hara K, Kuroda K, Hibi H, Okido M, Ueda M. A new application of cell-free bone regeneration: immobilizing stem cells from human exfoliated deciduous teeth-conditioned medium onto titanium implants using atmospheric pressure plasma treatment. Stem Cell Res Ther 2015; 6:124. [PMID: 26088364 PMCID: PMC4501071 DOI: 10.1186/s13287-015-0114-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Revised: 04/30/2015] [Accepted: 06/11/2015] [Indexed: 12/13/2022] Open
Abstract
Introduction Surface modification of titanium (Ti) implants promotes bone formation and shortens the osseointegration period. The aim of this study was to promote bone regeneration and stability around implants using atmospheric pressure plasma (APP) pretreatment. This was followed by immobilization of stem cells from human exfoliated deciduous teeth-conditioned medium (SHED-CM) on the Ti implant surface. Methods Ti samples (implants, discs, powder) were treated with APP for 30 seconds. Subsequently, these were immobilized on the treated Ti surface, soaked and agitated in phosphate-buffered saline or SHED-CM for 24 hours at 37 °C. The surface topography of the Ti implants was observed using scanning electron microscopy with energy dispersive X-ray spectroscopy. In vivo experiments using Ti implants placed on canine femur bone were then conducted to permit histological analysis at the bone-implant boundary. For the in vitro experiments, protein assays (SDS-PAGE, Bradford assay, liquid chromatography-ion trap mass spectrometry) and canine bone marrow stromal cell (cBMSC) attachment assays were performed using Ti discs or powder. Results In the in vitro study, treatment of Ti implant surfaces with SHED-CM led to calcium phosphate and extracellular matrix protein immobilization. APP pretreatment increased the amount of SHED-CM immobilized on Ti powder, and contributed to increased cBMSC attachment on Ti discs. In the in vivo study, histological analysis revealed that the Ti implants treated with APP and SHED-CM stimulated new bone formation around implants. Conclusions Implant device APP pretreatment followed by SHED-CM immobilization may be an effective application to facilitate bone regeneration around dental implants.
Collapse
Affiliation(s)
- Masahiro Omori
- Department of Oral and Maxillofacial Surgery, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8550, Japan.
| | - Shuhei Tsuchiya
- Department of Oral and Maxillofacial Surgery, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8550, Japan.
| | - Kenji Hara
- Department of Oral and Maxillofacial Surgery, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8550, Japan.
| | - Kensuke Kuroda
- EcoTopia Science Institute, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8502, Japan.
| | - Hideharu Hibi
- Department of Oral and Maxillofacial Surgery, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8550, Japan.
| | - Masazumi Okido
- EcoTopia Science Institute, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8502, Japan.
| | - Minoru Ueda
- Department of Oral and Maxillofacial Surgery, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8550, Japan.
| |
Collapse
|
165
|
Morelli S, Salerno S, Holopainen J, Ritala M, De Bartolo L. Osteogenic and osteoclastogenic differentiation of co-cultured cells in polylactic acid-nanohydroxyapatite fiber scaffolds. J Biotechnol 2015; 204:53-62. [PMID: 25858154 DOI: 10.1016/j.jbiotec.2015.03.023] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Revised: 03/27/2015] [Accepted: 03/31/2015] [Indexed: 01/07/2023]
Abstract
The design of bone substitutes involves the creation of a microenvironment supporting molecular cross-talk between cells and scaffolds during tissue formation and remodelling. Bone remodelling process includes the cooperation of bone-building cells and bone-resorbing cells. In this paper we developed polylactic acid (PLA) and composite PLA-nanohydroxyapatite (nHA) scaffolds with 20 and 50wt.% of nHA by electrospinning technique to be used in bone tissue engineering. The developed scaffolds have different fiber diameter, porosity with interconnected pores and mechanical properties. Taking cues from the bone environment features we investigated the differentiation of human mesenchymal stem cells (hMSCs) from bone marrow in osteoblasts and the osteoclastogenesis in the developed scaffolds in homotypic and in co-culture up to 46 days. PLA and composite PLA-nHA scaffolds induced osteogenic and osteoclastogenic differentiation. Both osteoblasts and osteoclasts displayed high expression of specific markers (osteopontin, osteocalcin, RANK, RANKL) and functions such as secretion of ALP, cathepsin K and TRAP activity on composite scaffolds especially on PLA-nHA containing 20wt.% of nHA. The heterotypic interactions between osteoblasts and osteoclasts co-cultured in the developed scaffolds triggered their functional differentiation and activation.
Collapse
Affiliation(s)
- Sabrina Morelli
- Institute on Membrane Technology, National Research Council of Italy, ITM-CNR, via P. Bucci cubo 17/C, I-87030 Rende, CS Italy
| | - Simona Salerno
- Institute on Membrane Technology, National Research Council of Italy, ITM-CNR, via P. Bucci cubo 17/C, I-87030 Rende, CS Italy
| | - Jani Holopainen
- Laboratory of Inorganic Chemistry, Department of Chemistry, University of Helsinki, PO Box 55, FI-00014 Helsinki, Finland
| | - Mikko Ritala
- Laboratory of Inorganic Chemistry, Department of Chemistry, University of Helsinki, PO Box 55, FI-00014 Helsinki, Finland
| | - Loredana De Bartolo
- Institute on Membrane Technology, National Research Council of Italy, ITM-CNR, via P. Bucci cubo 17/C, I-87030 Rende, CS Italy.
| |
Collapse
|
166
|
VILANI GNL, RUELLAS ACDO, MATTOS CT, FERNANDES DJ, ELIAS CN. Influence of cortical thickness on the stability of mini-implants with microthreads. Braz Oral Res 2015; 29:S1806-83242015000100220. [DOI: 10.1590/1807-3107bor-2015.vol29.0023] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Accepted: 09/23/2014] [Indexed: 11/22/2022] Open
|
167
|
Mechanical Study of Polycaprolactone-hydroxyapatite Porous Scaffolds Created by Porogen-based Solid Freeform Fabrication Method. J Appl Biomater Funct Mater 2014; 12:145-54. [DOI: 10.5301/jabfm.5000163] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/22/2012] [Indexed: 11/20/2022] Open
Abstract
Materials and Methods Polycaprolactone (PCL) and polycaprolactone-hydroxyapatite (PCL-HA) scaffolds with 600-μm pore size were fabricated by drop-on-demand printing (DDP) structured porogen method followed with injection molding. Specimens with special dimensions of 4.2×4.2×5.4 mm3 and 6.6×6.6×13.8 mm3 were designed and fabricated for compression and tensile tests, respectively. The mechanical study was performed on both solid and porous PCL and PCL-HA samples. The effect on mechanical properties of the HA content ratio in PCL-HA composites was investigated. Results Porous scaffold made of 80/20 PCL-HA composite had an ultimate compressive strength of 3.7±0.2 MPa and compression modulus of 61.4±3.4 MPa, which is in the range of reported trabecular bone's compressive strength. Increasing the concentration of HA in the composites raised compressive properties and stiffness significantly (P<0.05), which demonstrates that PCL-HA composites have the potential for application in bone regeneration. Tensile test of solid PCL and PCL-HA composites showed that the ultimate tensile strength and tensile modulus increased with increases of the concentration of HA in the composites. The tensile test was also conducted on PCL porous scaffold; the result indicated that the scaffold was slightly softer and weaker in tension compared with compression. Conclusions Combining compression and tensile test results, our study may guide the possible application of these biomaterials in bone tissue engineering and support further development of microstructure-based models of scaffold mechanical properties.
Collapse
|
168
|
Uzbek UH, Rahman SA, Alam MK, Gillani SW. Bone Forming Potential of An-Organic Bovine Bone Graft: A Cone Beam CT study. J Clin Diagn Res 2014; 8:ZC73-6. [PMID: 25654037 DOI: 10.7860/jcdr/2014/8557.5352] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2014] [Accepted: 05/14/2014] [Indexed: 11/24/2022]
Abstract
PURPOSE An-organic bovine bone graft is a xenograft with the potential of bone formation. The aim of this study was to evaluate the bone density using cone beam computed tomography scans around functional endosseous implant in the region of both augmented maxillary sinus with the an-organic bovine bone graft and the alveolar bone over which the graft was placed to provide space for the implants. MATERIALS AND METHODS Sterile freeze dried bovine bone graft produced by National Tissue Bank, University Sains, Malaysia was used for stage-1 implant placement with maxillary sinus augmentation in a total of 19 subjects with 19 implants. The age of all subjects ranged between 40-60 years with a mean age 51±4.70. All subjects underwent a follow up CT scan using PlanmecaPromax 3D(®) Cone beam computed tomography scanner at the Radiology department, Hospital University Sains, Malaysia. The collected data was then analysed to evaluate bone density in Hounsfield Units using PlanmecaRomexis" Imaging Software 2.2(®) which is specialized accompanying software of the cone beam computed tomography machine. RESULTS There was bone formation seen at the site of the augmented sinus. A significant increase (p<0.005) in bone density was reported at the augmented site compared to the bone density of the existing alveolar bone. CONCLUSION An-organic bovine bone graft is an osteoconductive material that can be used for the purpose of maxillary sinus augmentation.
Collapse
Affiliation(s)
- Usman Haider Uzbek
- Masters Student, Department of Oral and Maxillo-facial Surgery, University Sains Malaysia , Kelantan, Malaysia
| | - Shaifulizan Ab Rahman
- Senior Lecturer, Department of Oral and Maxillo-facial Surgery, University Sains Malaysia , Kelantan, Malaysia
| | | | - Syed Wasif Gillani
- Senior Lecturer, Discipline of Pharmacy, Monash University Malaysia , Selangor, Malaysia
| |
Collapse
|
169
|
Material Properties of the Mandibular Trabecular Bone. J Med Eng 2014; 2014:470539. [PMID: 27006933 PMCID: PMC4782746 DOI: 10.1155/2014/470539] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Accepted: 09/09/2014] [Indexed: 11/23/2022] Open
Abstract
The present paper introduces a numerical simulation aided, experimental method for the measurement of Young's modulus of the trabecular substance in the human mandible. Compression tests were performed on fresh cadaveric samples containing trabecular bone covered with cortical layer, thus avoiding the destruction caused by the sterilization, preservation, and storage and the underestimation of the stiffness resulting from the individual failure of the trabeculae cut on the surfaces. The elastic modulus of the spongiosa was determined by the numerical simulation of each compression test using a specimen specific finite element model of each sample. The received mandibular trabecular bone Young's modulus values ranged from 6.9 to 199.5 MPa.
Collapse
|
170
|
Cheng A, Humayun A, Cohen DJ, Boyan BD, Schwartz Z. Additively manufactured 3D porous Ti-6Al-4V constructs mimic trabecular bone structure and regulate osteoblast proliferation, differentiation and local factor production in a porosity and surface roughness dependent manner. Biofabrication 2014; 6:045007. [PMID: 25287305 DOI: 10.1088/1758-5082/6/4/045007] [Citation(s) in RCA: 125] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Additive manufacturing by laser sintering is able to produce high resolution metal constructs for orthopedic and dental implants. In this study, we used a human trabecular bone template to design and manufacture Ti-6Al-4V constructs with varying porosity via laser sintering. Characterization of constructs revealed interconnected porosities ranging from 15-70% with compressive moduli of 2579-3693 MPa. These constructs with macro porosity were further surface-treated to create a desirable multi-scale micro-/nano-roughness, which has been shown to enhance the osseointegration process. Osteoblasts (MG63 cells) exhibited high viability when grown on the constructs. Proliferation (DNA) and alkaline phosphatase specific activity, an early differentiation marker, decreased as porosity increased, while osteocalcin, a late differentiation marker, as well as osteoprotegerin, vascular endothelial growth factor and bone morphogenetic proteins 2 and 4 increased with increasing porosity. Three-dimensional (3D) constructs with the highest porosity and surface modification supported the greatest osteoblast differentiation and local factor production. These results indicate that additively manufactured 3D porous constructs mimicking human trabecular bone and produced with additional surface treatment can be customized for increased osteoblast response. Increased factors for osteoblast maturation and differentiation on high porosity constructs suggest the enhanced performance of these surfaces for increasing osseointegration in vivo.
Collapse
Affiliation(s)
- Alice Cheng
- Wallace A Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia, USA. Department of Biomedical Engineering, Peking University, Beijing, People's Republic of China
| | | | | | | | | |
Collapse
|
171
|
Orellana BR, Puleo DA. Tailored sequential drug release from bilayered calcium sulfate composites. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2014; 43:243-52. [PMID: 25175211 PMCID: PMC4152730 DOI: 10.1016/j.msec.2014.06.044] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Revised: 06/04/2014] [Accepted: 06/30/2014] [Indexed: 12/26/2022]
Abstract
The current standard for treating infected bony defects, such as those caused by periodontal disease, requires multiple time-consuming steps and often multiple procedures to fight the infection and recover lost tissue. Releasing an antibiotic followed by an osteogenic agent from a synthetic bone graft substitute could allow for a streamlined treatment, reducing the need for multiple surgeries and thereby shortening recovery time. Tailorable bilayered calcium sulfate (CS) bone graft substitutes were developed with the ability to sequentially release multiple therapeutic agents. Bilayered composite samples having a shell and core geometry were fabricated with varying amounts (1 or 10 wt.%) of metronidazole-loaded poly(lactic-co-glycolic acid) (PLGA) particles embedded in the shell and simvastatin directly loaded into either the shell, core, or both. Microcomputed tomography showed the overall layered geometry as well as the uniform distribution of PLGA within the shells. Dissolution studies demonstrated that the amount of PLGA particles (i.e., 1 vs. 10 wt.%) had a small but significant effect on the erosion rate (3% vs. 3.4%/d). Mechanical testing determined that introducing a layered geometry had a significant effect on the compressive strength, with an average reduction of 35%, but properties were comparable to those of mandibular trabecular bone. Sustained release of simvastatin directly loaded into CS demonstrated that changing the shell to core volume ratio dictates the duration of drug release from each layer. When loaded together in the shell or in separate layers, sequential release of metronidazole and simvastatin was achieved. By introducing a tunable, layered geometry capable of releasing multiple drugs, CS-based bone graft substitutes could be tailored in order to help streamline the multiple steps needed to regenerate tissue in infected defects.
Collapse
Affiliation(s)
- Bryan R Orellana
- Department of Biomedical Engineering, University of Kentucky, Lexington, KY, USA
| | - David A Puleo
- Department of Biomedical Engineering, University of Kentucky, Lexington, KY, USA.
| |
Collapse
|
172
|
The biomechanical function of periodontal ligament fibres in orthodontic tooth movement. PLoS One 2014; 9:e102387. [PMID: 25036099 PMCID: PMC4103804 DOI: 10.1371/journal.pone.0102387] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2014] [Accepted: 06/18/2014] [Indexed: 11/19/2022] Open
Abstract
Orthodontic tooth movement occurs as a result of resorption and formation of the alveolar bone due to an applied load, but the stimulus responsible for triggering orthodontic tooth movement remains the subject of debate. It has been suggested that the periodontal ligament (PDL) plays a key role. However, the mechanical function of the PDL in orthodontic tooth movement is not well understood as most mechanical models of the PDL to date have ignored the fibrous structure of the PDL. In this study we use finite element (FE) analysis to investigate the strains in the alveolar bone due to occlusal and orthodontic loads when PDL is modelled as a fibrous structure as compared to modelling PDL as a layer of solid material. The results show that the tension-only nature of the fibres essentially suspends the tooth in the tooth socket and their inclusion in FE models makes a significant difference to both the magnitude and distribution of strains produced in the surrounding bone. The results indicate that the PDL fibres have a very important role in load transfer between the teeth and alveolar bone and should be considered in FE studies investigating the biomechanics of orthodontic tooth movement.
Collapse
|
173
|
PEKEDIS MAHMUT, YILDIZ HASAN. NUMERICAL ANALYSIS OF A PROJECTILE PENETRATION INTO THE HUMAN HEAD VIA MESHLESS METHOD. J MECH MED BIOL 2014. [DOI: 10.1142/s0219519414500596] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
In recent years, physicists, engineers and medical scientists have tried to demonstrate the biomechanics of gunshot wounds with numerical methods and experimental observations. Currently, the finite element method (FEM) is the most widely used numerical method among the studies related to ballistic wound injuries. However, when the FEM is used for the penetration analysis, the path of the projectile in the skull is subjected to extremely large deformations which will introduce errors due to distortion of elements. To overcome this error, the meshfree technique was established to simulate the gunshot wound as a preliminary study in which the skull was modeled by smoothed particle hydrodynamics (SPH) and the projectile was modeled by nondeformable rigid elements. In order to simulate a realistic penetration phenomenon, orthotropic material properties were defined for different regions (forehead, zygomatic and mandible) with material principal axis along the surface of the bones. Human response to the ballistics impacts were determined in terms of force occurring along the pathway of the bullet in the skull, residual velocity of the projectile and penetration depth. The obtained results were compared with the data reported in literature. As a result, mechanical behavior of the head under ballistic impacts simulated by the SPH, compared well with the results determined by the data given in literature, which indicates the applicability of the SPH method as a powerful technique in simulating different gunshot wound mechanisms.
Collapse
Affiliation(s)
- MAHMUT PEKEDIS
- Ege University, Faculty of Engineering, Department of Mechanical Engineering, 35100 Izmir, Turkey
| | - HASAN YILDIZ
- Ege University, Faculty of Engineering, Department of Mechanical Engineering, 35100 Izmir, Turkey
| |
Collapse
|
174
|
Orellana BR, Hilt JZ, Puleo DA. Drug release from calcium sulfate-based composites. J Biomed Mater Res B Appl Biomater 2014; 103:135-42. [PMID: 24788686 DOI: 10.1002/jbm.b.33181] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2013] [Revised: 03/11/2014] [Accepted: 04/05/2014] [Indexed: 12/24/2022]
Abstract
To help reduce the need for autografts, calcium sulfate (CS)-based bone graft substitutes are being developed to provide a stable platform to aid augmentation while having the ability to release a broad range of bioactive agents. CS has an excellent reputation as a biocompatible and osteoconductive substance, but addition of bioactive agents may further enhance these properties. Samples were produced with either directly loaded small, hydrophobic molecule (i.e., simvastatin), directly loaded hydrophilic protein (i.e., lysozyme), or 1 and 10 wt % of fast-degrading poly(β-amino ester) (PBAE) particles containing protein. Although sustained release of directly loaded simvastatin was achieved, direct loading of small amounts of lysozyme resulted in highly variable release. Direct loading of a larger amount of protein generated a large burst, 65% of total loading, followed by sustained release of protein. Release of lysozyme from 1 wt % of PBAE particles embedded into CS was more controllable than when directly loaded, and for 10 wt % of protein-loaded PBAE particles, a higher burst was followed by sustained release, comparable to the results for the high direct loading. Compression testing determined that incorporation of directly loaded drug or drug-loaded PBAE particles weakened CS. In particular, PBAE particles had a significant effect on the strength of the composites, with a 25 and 80% decrease in strength for 1 and 10 wt % particle loadings, respectively. CS-based composites demonstrated the ability to sustainably release both macromolecules and small molecules, supporting the potential for these materials to release a range of therapeutic agents.
Collapse
Affiliation(s)
- Bryan R Orellana
- Department of Biomedical Engineering, University of Kentucky, Lexington, Kentucky
| | | | | |
Collapse
|
175
|
Favot LM, Berry-Kromer V, Haboussi M, Thiebaud F, Ben Zineb T. Numerical study of the influence of material parameters on the mechanical behaviour of a rehabilitated edentulous mandible. J Dent 2014; 42:287-97. [DOI: 10.1016/j.jdent.2013.11.027] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Revised: 11/28/2013] [Accepted: 11/30/2013] [Indexed: 10/25/2022] Open
|
176
|
Kim JE, Shin JM, Oh SO, Yi WJ, Heo MS, Lee SS, Choi SC, Huh KH. The three-dimensional microstructure of trabecular bone: Analysis of site-specific variation in the human jaw bone. Imaging Sci Dent 2013; 43:227-33. [PMID: 24380061 PMCID: PMC3873310 DOI: 10.5624/isd.2013.43.4.227] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2013] [Revised: 07/24/2013] [Accepted: 08/03/2013] [Indexed: 11/18/2022] Open
Abstract
Purpose This study was performed to analyze human maxillary and mandibular trabecular bone using the data acquired from micro-computed tomography (micro-CT), and to characterize the site-specific microstructures of trabeculae. Materials and Methods Sixty-nine cylindrical bone specimens were prepared from the mandible and maxilla. They were divided into 5 groups by region: the anterior maxilla, posterior maxilla, anterior mandible, posterior mandible, and mandibular condyle. After the specimens were scanned using a micro-CT system, three-dimensional microstructural parameters such as the percent bone volume, bone specific surface, trabecular thickness, trabecular separation, trabecular number, structure model index, and degrees of anisotropy were analyzed. Results Among the regions other than the condylar area, the anterior mandibular region showed the highest trabecular thickness and the lowest value for the bone specific surface. On the other hand, the posterior maxilla region showed the lowest trabecular thickness and the highest value for the bone specific surface. The degree of anisotropy was lowest at the anterior mandible. The condyle showed thinner trabeculae with a more anisotropic arrangement than the other mandibular regions. Conclusion There were microstructural differences between the regions of the maxilla and mandible. These results suggested that different mechanisms of external force might exist at each site.
Collapse
Affiliation(s)
- Jo-Eun Kim
- Department of Oral and Maxillofacial Radiology and Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Korea
| | - Jae-Myung Shin
- Department of Oral and Maxillofacial Surgery, Ilsan Paik Hospital, Inje University College of Medicine, Goyang, Korea
| | | | - Won-Jin Yi
- Department of Oral and Maxillofacial Radiology and Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Korea
| | - Min-Suk Heo
- Department of Oral and Maxillofacial Radiology and Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Korea
| | - Sam-Sun Lee
- Department of Oral and Maxillofacial Radiology and Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Korea
| | - Soon-Chul Choi
- Department of Oral and Maxillofacial Radiology and Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Korea
| | - Kyung-Hoe Huh
- Department of Oral and Maxillofacial Radiology and Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Korea
| |
Collapse
|
177
|
Ho JT, Wu J, Huang HL, Chen MYC, Fuh LJ, Hsu JT. Trabecular bone structural parameters evaluated using dental cone-beam computed tomography: cellular synthetic bones. Biomed Eng Online 2013; 12:115. [PMID: 24207062 PMCID: PMC3826852 DOI: 10.1186/1475-925x-12-115] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Accepted: 11/07/2013] [Indexed: 11/10/2022] Open
Abstract
Objective This study compared the adequacy of dental cone beam computed tomography (CBCT) and micro computed tomography (micro-CT) in evaluating the structural parameters of trabecular bones. Methods The cellular synthetic bones in 4 density groups (Groups 1–4: 0.12, 0.16, 0.20, and 0.32 g/cm3) were used in this study. Each group comprised 8 experimental specimens that were approximately 1 cm3. Dental CBCT and micro-CT scans were conducted on each specimen to obtain independent measurements of the following 4 trabecular bone structural parameters: bone volume fraction (BV/TV), specific bone surface (BS/BV), trabecular thickness (Tb.Th.), and trabecular separation (Tb.Sp.). Wilcoxon signed ranks tests were used to compare the measurement variations between the dental CBCT and micro-CT scans. A Spearman analysis was conducted to calculate the correlation coefficients (r) of the dental CBCT and micro-CT measurements. Results and Conclusion Of the 4 groups, the BV/TV and Tb.Th. measured using dental CBCT were larger compared with those measured using micro-CT. By contrast, the BS/BV measured using dental CBCT was significantly less compared with those measured using micro-CT. Furthermore, in the low-density groups (Groups 1 and 2), the Tb.Sp. measured using dental CBCT was smaller compared with those measured using micro-CT. However, the Tb.Sp. measured using dental CBCT was slightly larger in the high-density groups (Groups 3 and 4) than it was in the low density groups. The correlation coefficients between the BV/TV, BS/BV, Tb.Th., and Tb.Sp. values measured using dental CBCT and micro-CT were 0.9296 (p < .001), 0.8061 (p < .001), 0.9390 (p < .001), and 0.9583 (p < .001), respectively. Although the dental CBCT and micro-CT approaches exhibited high correlations, the absolute values of BV/TV, BS/BV, Tb.Th., Tb.Sp. differed significantly between these measurements. Additional studies must be conducted to evaluate using dental CBCT in clinical practice.
Collapse
Affiliation(s)
| | | | | | | | | | - Jui-Ting Hsu
- School of Dentistry, College of Medicine, China Medical University, Taichung 404, Taiwan.
| |
Collapse
|
178
|
Huang HL, Tsai MT, Su KC, Li YF, Hsu JT, Chang CH, Fuh LJ, Wu AYJ. Relation between initial implant stability quotient and bone-implant contact percentage: an in vitro model study. Oral Surg Oral Med Oral Pathol Oral Radiol 2013; 116:e356-61. [DOI: 10.1016/j.oooo.2012.01.037] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2011] [Revised: 01/13/2012] [Accepted: 01/23/2012] [Indexed: 11/29/2022]
|
179
|
Bettach R, Taschieri S, Boukhris G, Del Fabbro M. Implant Survival after Preparation of the Implant Site Using a Single Bur: A Case Series. Clin Implant Dent Relat Res 2013; 17:13-21. [DOI: 10.1111/cid.12082] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Raphaèl Bettach
- New York University; New York, NY USA
- private practice; Gretz-Armainvilliers France
| | - Silvio Taschieri
- Department of Biomedical, Surgical and Dental Sciences; University of Milan; Milan Italy
- Dental Clinic; IRCCS Istituto Ortopedico Galeazzi; Milan Italy
| | | | - Massimo Del Fabbro
- University of Milan; Milan Italy
- Department of Biomedical, Surgical and Dental Sciences; IRCCS Istituto Ortopedico Galeazzi; Milan Italy
| |
Collapse
|
180
|
Monje A, Monje F, González-García R, Suarez F, Galindo-Moreno P, García-Nogales A, Wang HL. Influence of Atrophic Posterior Maxilla Ridge Height on Bone Density and Microarchitecture. Clin Implant Dent Relat Res 2013; 17:111-9. [DOI: 10.1111/cid.12075] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Alberto Monje
- Graduate Periodontics; Department of Periodontics and Oral Medicine; University of Michigan School of Dentistry; Ann Arbor MI USA
| | - Florencio Monje
- Oral and Maxillofacial Surgeon; CICOM; Center of Implantology, Oral and Maxillofacial Surgery; Badajoz Spain
| | - Raúl González-García
- Oral and Maxillofacial Surgeon; CICOM; Center of Implantology, Oral and Maxillofacial Surgery; Badajoz Spain
| | - Fernando Suarez
- Graduate Periodontics; Department of Periodontics and Oral Medicine; University of Michigan School of Dentistry; Ann Arbor MI USA
| | - Pablo Galindo-Moreno
- Department of Oral Surgery and Implant Dentistry; University of Granada; Granada Spain
| | | | - Hom-Lay Wang
- Graduate Periodontics; Department of Periodontics and Oral Medicine; University of Michigan School of Dentistry; Ann Arbor MI USA
| |
Collapse
|
181
|
Demenko V, Linetsky I, Nesvit V, Linetska L, Shevchenko A. FE study of bone quality effect on load-carrying ability of dental implants. Comput Methods Biomech Biomed Engin 2013; 17:1751-61. [DOI: 10.1080/10255842.2013.766173] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
182
|
Mechanical Evaluation of Orthodontic Mini-Implants of Different Lengths. J Oral Maxillofac Surg 2013; 71:479-86. [DOI: 10.1016/j.joms.2012.10.002] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2012] [Revised: 10/01/2012] [Accepted: 10/01/2012] [Indexed: 12/18/2022]
|
183
|
Rahman CV, Kuhn G, White LJ, Kirby GTS, Varghese OP, McLaren JS, Cox HC, Rose FRAJ, Müller R, Hilborn J, Shakesheff KM. PLGA/PEG-hydrogel composite scaffolds with controllable mechanical properties. J Biomed Mater Res B Appl Biomater 2013; 101:648-55. [DOI: 10.1002/jbm.b.32867] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2012] [Revised: 10/31/2012] [Accepted: 11/11/2012] [Indexed: 11/10/2022]
|
184
|
Lee KJ, Kim YG, Park JW, Lee JM, Suh JY. Influence of crown-to-implant ratio on periimplant marginal bone loss in the posterior region: a five-year retrospective study. J Periodontal Implant Sci 2012; 42:231-6. [PMID: 23346467 PMCID: PMC3543939 DOI: 10.5051/jpis.2012.42.6.231] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Accepted: 11/18/2012] [Indexed: 11/08/2022] Open
Abstract
Purpose The aim of this study was to evaluate the influence of the crown-to-implant (C/I) ratio on the change in marginal bone level around the implant and to determine the site-related factors influencing the relationship between the C/I ratio and periimplant marginal bone loss. Methods A total of 259 implants from 175 patients were evaluated at a mean follow-up of five years. Implants were divided into two groups according to their C/I ratios: ≤1, and >1. Site-related factors having an influence on the relationship between C/I ratio and periimplant marginal bone loss were analyzed according to the implant location, implant diameter, implant manufacturer, prosthesis type, and guided bone regeneration (GBR) procedure. Results It was found that 1) implants with a C/I ratio below 1 exhibited greater periimplant marginal bone loss than implants with a C/I ratio more than 1, 2) site-related factors had an effect on periimplant marginal bone loss, except for the implant system used, 3) the C/I ratio was the factor having more dominant influence on periimplant marginal bone loss, compared with implant diameter, prosthesis type, implant location, and GBR procedure, 4) implants with a C/I ratio below 1 showed greater periimplant marginal bone loss than implants with a C/I ratio greater than 1 in the maxilla, but not in the mandible, 5) and periimplant marginal bone loss was more affected by the implant system than the C/I ratio. Conclusions Within the limitations of this study, implants with a higher C/I ratio exhibited less marginal bone loss than implants with a lower C/I ratio in the posterior regions. The C/I ratio was a more dominant factor affecting periimplant marginal bone loss in the maxilla than the mandible. Meanwhile, the implant system was a more dominant factor influencing periimplant marginal bone loss than the C/I ratio.
Collapse
Affiliation(s)
- Kyung-Jin Lee
- Department of Periodontology, Kyungpook National University School of Dentistry, Daegu, Korea
| | | | | | | | | |
Collapse
|
185
|
The modular endoprosthesis for mandibular body replacement. Part 2: Finite element analysis of endoprosthesis reconstruction of the mandible. J Craniomaxillofac Surg 2012; 40:e487-97. [DOI: 10.1016/j.jcms.2012.03.010] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2011] [Revised: 03/12/2012] [Accepted: 03/12/2012] [Indexed: 11/24/2022] Open
|
186
|
Di Stefano D, Mura S, Cazzaniga A, Arosio P. Definizione della qualità ossea registrata nelle diverse aree anatomo-strutturali. ACTA ACUST UNITED AC 2012. [DOI: 10.1016/j.ios.2012.04.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
187
|
Lu L, Zhang Q, Wootton D, Chiou R, Li D, Lu B, Lelkes P, Zhou J. Biocompatibility and biodegradation studies of PCL/β-TCP bone tissue scaffold fabricated by structural porogen method. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2012; 23:2217-2226. [PMID: 22669285 DOI: 10.1007/s10856-012-4695-2] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2011] [Accepted: 05/23/2012] [Indexed: 06/01/2023]
Abstract
Three-dimensional printer (3DP) (Z-Corp) is a solid freeform fabrication system capable of generating sub-millimeter physical features required for tissue engineering scaffolds. By using plaster composite materials, 3DP can fabricate a universal porogen which can be injected with a wide range of high melting temperature biomaterials. Here we report results toward the manufacture of either pure polycaprolactone (PCL) or homogeneous composites of 90/10 or 80/20 (w/w) PCL/beta-tricalcium phosphate (β-TCP) by injection molding into plaster composite porogens fabricated by 3DP. The resolution of printed plaster porogens and produced scaffolds was studied by scanning electron microscopy. Cytotoxicity test on scaffold extracts and biocompatibility test on the scaffolds as a matrix supporting murine osteoblast (7F2) and endothelial hybridoma (EAhy 926) cells growth for up to 4 days showed that the porogens removal process had only negligible effects on cell proliferation. The biodegradation tests of pure PCL and PCL/β-TCP composites were performed in DMEM with 10 % (v/v) FBS for up to 6 weeks. The PCL/β-TCP composites show faster degradation rate than that of pure PCL due to the addition of β-TCP, and the strength of 80/20 PCL/β-TCP composite is still suitable for human cancellous bone healing support after 6 weeks degradation. Combining precisely controlled porogen fabrication structure, good biocompatibility, and suitable mechanical properties after biodegradation, PCL/β-TCP scaffolds fabricated by 3DP porogen method provide essential capability for bone tissue engineering.
Collapse
Affiliation(s)
- Lin Lu
- Department of Mechanical Engineering and Mechanics, Drexel University, Philadelphia, PA 19104, USA
| | | | | | | | | | | | | | | |
Collapse
|
188
|
Gröning F, Fagan M, O'Higgins P. Modeling the human mandible under masticatory loads: which input variables are important? Anat Rec (Hoboken) 2012; 295:853-63. [PMID: 22467624 DOI: 10.1002/ar.22455] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Accepted: 03/06/2012] [Indexed: 11/08/2022]
Abstract
Finite element analyses (FEA) that have simulated masticatory loadings of the human mandible differ significantly with regard to their basic input variables such as material properties, constraints, and applied forces. With sensitivity analyses it is possible to assess how the choice of different input values and the degree of model simplification affect FEA results. However, published FEA studies are rarely accompanied by sensitivity analyses so that the robusticity of their results is impossible to assess. Here, we conduct a sensitivity analysis with an FE model of a human mandible to quantify the relative importance of several modeling decisions: (1) the material properties assigned to the cancellous bone tissue; (2) the inclusion or not of the periodontal ligament; (3) the constraints at the joints and bite point; and (4) the orientation of applied muscle forces. We study the effects of varying these properties by analysing the strain magnitudes and directions across the model surface. In addition, we perform a geometric morphometric analysis of the deformation resulting from the loading of each model. The results show that the effects of altering the different model properties can be significant and that most effects are potentially large enough to cause problems for the biological interpretation of FEA results. We therefore recommend that researchers conduct more sensitivity analyses than at present to assess the robusticity of their FEA results and their biological conclusions.
Collapse
Affiliation(s)
- Flora Gröning
- Department of Archaeology, University of York, York, UK.
| | | | | |
Collapse
|
189
|
Pérez MA, Prados-Frutos JC, Bea JA, Doblaré M. Stress transfer properties of different commercial dental implants: a finite element study. Comput Methods Biomech Biomed Engin 2012; 15:263-73. [DOI: 10.1080/10255842.2010.527834] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
190
|
Mattos CMA, Las Casas EB, Dutra IGR, Sousa HA, Guerra SMG. Numerical analysis of the biomechanical behaviour of a weakened root after adhesive reconstruction and post-core rehabilitation. J Dent 2012; 40:423-32. [PMID: 22343185 DOI: 10.1016/j.jdent.2012.02.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2011] [Revised: 02/07/2012] [Accepted: 02/08/2012] [Indexed: 11/26/2022] Open
Abstract
OBJECTIVES The purpose of this study was to perform a finite element analysis to determine whether adhesive reconstruction is able to restore the original biomechanical behaviour of weakened roots, in terms of fracture resistance, when compared with post/crown-restored teeth with intact roots. METHODS A three-dimensional model of a maxillary central incisor was created. The model simulated an endodontically treated tooth restored with a glass-fibre post, a composite-resin core and a metal crown (Model 1). Based on Model 1, a new volume was created in the root cervical third that represented the area where the dentine structure was lost, resulting in a structurally damaged root (Model 2). A 100N load was applied to the palatal surface at 130° from the long axis of the tooth. After processing (Ansys(®) 10.0 - Canonsburg, PA, USA), the principal normal stress data were analyzed (S1, tensile; S3, compressive). RESULTS The models demonstrated a similar S1 distribution concentrated in the lingual cervical region but different S1 levels (Model 1: 28.7MPa; Model 2: 35.3MPa). The S3 distribution indicated differences in behaviour between the models (Model 1: -18 to -27MPa along the buccal root surface; Model 2: -25 to -32MPa on the post buccal surface and along the buccal root wall). CONCLUSIONS Although the stress distribution within the root walls remained below the ultimate stress limit of the root dentine, the adhesive reconstruction of the weakened roots did not recover the load resistance of structurally intact roots. CLINICAL SIGNIFICANCE The decision of when to prosthetically rehabilitate weakened roots with cervical dentine structural tissue loss is a challenge for clinicians. A 'monoblock' adhesive reconstruction has been proposed for root reinforcement. During treatment planning, the possibility of restoring the mechanical resistance of the root must be evaluated if successful long-term results are to be achieved.
Collapse
Affiliation(s)
- C M A Mattos
- PPGMEC, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.
| | | | | | | | | |
Collapse
|
191
|
Relation between insertion torque and bone-implant contact percentage: an artificial bone study. Clin Oral Investig 2012; 16:1679-84. [PMID: 22228023 DOI: 10.1007/s00784-011-0658-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2011] [Accepted: 12/08/2011] [Indexed: 10/14/2022]
Abstract
OBJECTIVES The purpose of this study was to determine the correlation between the peak insertion torque value (ITV) of a dental implant and the bone-implant contact percentage (BIC%). MATERIAL AND METHODS Dental implants were inserted into specimens comprising a 2-mm-thick artificial cortical shell representing cortical bone and artificial foam bone representing cancellous bone with four densities (groups 1 to 4--0.32, 0.20, 0.16, and 0.12 g/cm(3)). Each specimen with an inserted implant was subjected to micro-computed tomography (micro-CT) scanning, from which the 3D BIC% values were calculated. Pearson's correlation coefficients (r) between the ITV and BIC% were calculated. RESULTS The ITVs in groups 1 to 4 were 56.2 ± 4.6 (mean±standard deviation), 45.6 ± 0.9, 43.3 ± 4.3, and 38.5 ± 3.4 N cm, respectively, and the corresponding BIC% values were 41.5 ± 0.5%, 39.0 ± 1.0%, 30.8 ± 1.1%, and 26.2 ± 1.6%. Pearson's correlation coefficient between the ITV and BIC% was r = 0.797 (P < 0.0001). CONCLUSION The initial implant stability, quantified as the ITV, was strongly positively correlated with the 3D BIC% obtained from micro-CT images. CLINICAL RELEVANCE The ITV of a dental implant can be used to predict the initial BIC%; this information may provide the clinician with important information on the optimal loading time.
Collapse
|
192
|
Dhillon A, Schneider P, Kuhn G, Reinwald Y, White LJ, Levchuk A, Rose FRAJ, Müller R, Shakesheff KM, Rahman CV. Analysis of sintered polymer scaffolds using concomitant synchrotron computed tomography and in situ mechanical testing. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2011; 22:2599-2605. [PMID: 21909640 DOI: 10.1007/s10856-011-4443-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Accepted: 08/29/2011] [Indexed: 05/31/2023]
Abstract
The mechanical behaviour of polymer scaffolds plays a vital role in their successful use in bone tissue engineering. The present study utilised novel sintered polymer scaffolds prepared using temperature-sensitive poly(DL-lactic acid-co-glycolic acid)/poly(ethylene glycol) particles. The microstructure of these scaffolds was monitored under compressive strain by image-guided failure assessment (IGFA), which combined synchrotron radiation computed tomography (SR CT) and in situ micro-compression. Three-dimensional CT data sets of scaffolds subjected to a strain rate of 0.01%/s illustrated particle movement within the scaffolds with no deformation or cracking. When compressed using a higher strain rate of 0.02%/s particle movement was more pronounced and cracks between sintered particles were observed. The results from this study demonstrate that IGFA based on simultaneous SR CT imaging and micro-compression testing is a useful tool for assessing structural and mechanical scaffold properties, leading to further insight into structure-function relationships in scaffolds for bone tissue engineering applications.
Collapse
Affiliation(s)
- A Dhillon
- Division of Drug Delivery and Tissue Engineering, Centre for Biomolecular Sciences, University of Nottingham, University Park, Nottingham, UK
| | | | | | | | | | | | | | | | | | | |
Collapse
|
193
|
Sansare K, Singh D, Karjodkar F. Changes in the fractal dimension on pre- and post-implant panoramic radiographs. Oral Radiol 2011. [DOI: 10.1007/s11282-011-0075-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
194
|
Law C, Bennani V, Lyons K, Swain M. Mandibular flexure and its significance on implant fixed prostheses: a review. J Prosthodont 2011; 21:219-24. [PMID: 22044758 DOI: 10.1111/j.1532-849x.2011.00798.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
PURPOSE The aims of this review are to determine the effect of mandibular flexure on the "implant-framework system," and analyze the existing literature on the topic. MATERIALS AND METHODS A MEDLINE and PubMed search was conducted to identify any articles in English related to the topic published up to May 2010 using the search words "mandible,""dental implants,""dental impression technique,""jaw movement,""dental stress analysis," and "mechanical stress." RESULTS The search identified 40 and 36 articles from MEDLINE and PubMed, respectively. Twenty articles met the inclusion criteria. CONCLUSIONS Mandibular flexure is a multifactorial phenomenon, and the effect of the implant-framework system in this is unclear. Studies have focused mainly on the fully edentulous mandible. These have found that mandibular flexure should be taken into consideration when designing a prosthesis and have suggested that dividing the prosthesis at the symphysis region, or into multiple implant fixed dental prostheses, may minimize the effect of mandibular flexure on the implant prosthesis. At this time, no studies have investigated the effect of mandibular flexure on long-span, unilateral, implant fixed prostheses. The clinical significance of mandibular flexure on the success of dental implant treatment is at this time unclear, and further research is needed.
Collapse
Affiliation(s)
- Constance Law
- Department of Oral Rehabilitation, University of Otago, Dunedin, New Zealand
| | | | | | | |
Collapse
|
195
|
Effect of replacement of mandibular defects with a modular endoprosthesis on bone mineral density in a monkey model. Int J Oral Maxillofac Surg 2011; 40:633-9. [DOI: 10.1016/j.ijom.2010.10.028] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2010] [Accepted: 10/27/2010] [Indexed: 11/20/2022]
|
196
|
Miyashiro M, Suedam V, Moretti Neto RT, Ferreira PM, Rubo JH. Validation of an experimental polyurethane model for biomechanical studies on implant supported prosthesis--tension tests. J Appl Oral Sci 2011; 19:244-8. [PMID: 21625741 PMCID: PMC4234337 DOI: 10.1590/s1678-77572011000300012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2009] [Accepted: 05/25/2010] [Indexed: 11/21/2022] Open
Abstract
OBJECTIVES The complexity and heterogeneity of human bone, as well as ethical issues, frequently hinder the development of clinical trials. The purpose of this in vitro study was to determine the modulus of elasticity of a polyurethane isotropic experimental model via tension tests, comparing the results to those reported in the literature for mandibular bone, in order to validate the use of such a model in lieu of mandibular bone in biomechanical studies. MATERIAL AND METHODS Forty-five polyurethane test specimens were divided into 3 groups of 15 specimens each, according to the ratio (A/B) of polyurethane reagents (PU-1: 1/0.5, PU-2: 1/1, PU-3: 1/1.5). RESULTS Tension tests were performed in each experimental group and the modulus of elasticity values found were 192.98 MPa (SD=57.20) for PU-1, 347.90 MPa (SD=109.54) for PU-2 and 304.64 MPa (SD=25.48) for PU-3. CONCLUSION The concentration of choice for building the experimental model was 1/1.
Collapse
Affiliation(s)
- Mariane Miyashiro
- Bauru School of Dentistry, University of São Paulo, Bauru, SP, Brazil
| | | | | | | | | |
Collapse
|
197
|
Hsu JT, Fuh LJ, Tu MG, Li YF, Chen KT, Huang HL. The effects of cortical bone thickness and trabecular bone strength on noninvasive measures of the implant primary stability using synthetic bone models. Clin Implant Dent Relat Res 2011; 15:251-61. [PMID: 21599830 DOI: 10.1111/j.1708-8208.2011.00349.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
PURPOSE This study investigated how the primary stability of a dental implant as measured by the insertion torque value (ITV), Periotest value (PTV), and implant stability quotient (ISQ) is affected by varying thicknesses of cortical bone and strengths of trabecular bone using synthetic bone models. MATERIALS AND METHODS Four synthetic cortical shells (with thicknesses of 0, 1, 2, and 3 mm) were attached to four cellular rigid polyurethane foams (with elastic moduli of 137, 47.5, 23, and 12.4 MPa) and one open-cell rigid polyurethane foam which mimic the osteoporotic bone (with an elastic modulus 6.5 MPa), to represent the jawbones with various cortical bone thicknesses and strengths of trabecular bone. A total of 60 bone specimens accompanied with implants was examined by a torque meter, Osstell resonance frequency analyzer, and Periotest electronic device. All data were statistically analyzed by two-way analysis of variance. In addition, second-order nonlinear regression was utilized to assess the correlations of the primary implant stability with the four cortex thicknesses and five strengths of trabecular bone. RESULTS ITV, ISQ, and PTV differed significantly (p < .05) and were strongly correlated with the thickness of cortical bone (R(2) > 0.9) and the elastic modulus of trabecular bone (R(2) = 0.74-0.99). CONCLUSIONS The initial stability at the time of implant placement is influenced by both the cortical bone thickness and the strength of trabecular bone; however, these factors are mostly nonlinearly correlated with ITV, PTV, and ISQ. Using ITV and PTV seems more suitable for identifying the primary implant stability in osteoporotic bone with a thin cortex.
Collapse
Affiliation(s)
- Jui-Ting Hsu
- School of Dentistry, China Medical University, Taiwan
| | | | | | | | | | | |
Collapse
|
198
|
Gröning F, Liu J, Fagan MJ, O'Higgins P. Why do humans have chins? Testing the mechanical significance of modern human symphyseal morphology with finite element analysis. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2011; 144:593-606. [PMID: 21404235 DOI: 10.1002/ajpa.21447] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2010] [Revised: 10/11/2010] [Indexed: 11/07/2022]
Abstract
The modern human mandibular symphysis differs from those of all other primates in being vertically orientated and possessing a chin, but the functional significance of this unique morphology is not well understood. Some hypotheses propose that it is an adaptation to specific loads occurring during masticatory function. This study uses finite element analysis to examine these symphyseal loads in a model of a modern human mandible. By modifying the symphyseal cross-sectional form, the mechanical significance of the presence of the chin and symphyseal orientation is tested, and modern human and Neanderthal symphyseal cross-sections are compared with regard to their ability to withstand different loads. The results show that changes in symphyseal form have profound effects on the strains. The presence of a chin leads to lower symphyseal strains overall, whereas a vertical orientation of the symphysis results in higher strains under wishboning, but not under vertical bending in the coronal plane and dorsoventral shear. Compared to Neanderthals, the modern human symphysis shows higher strains during dorsoventral shear and wishboning, but is as effective as the Neanderthal symphysis in resisting vertical bending in the coronal plane and the loads resulting from simulated incision and unilateral molar biting. In general, the results of this study corroborate prior hypotheses about the mechanical effects of the human chin and vertical symphyseal orientation and support the idea that the relative importance of wishboning and vertical bending in the coronal plane might have played a role in the evolution of modern human symphyseal morphology.
Collapse
Affiliation(s)
- Flora Gröning
- Department of Archaeology and Hull York Medical School, University of York, York, UK.
| | | | | | | |
Collapse
|
199
|
Moretti Neto RT, Hiramatsu DA, Suedam V, Conti PCR, Rubo JH. Validation of an experimental polyurethane model for biomechanical studies on implant-supported prosthesis--compression tests. J Appl Oral Sci 2011; 19:47-51. [PMID: 21437469 PMCID: PMC4245863 DOI: 10.1590/s1678-77572011000100010] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2009] [Accepted: 04/27/2010] [Indexed: 11/22/2022] Open
Abstract
Objectives The complexity and heterogeneity of human bone, as well as ethical issues, most
always hinder the performance of clinical trials. Thus, in vitro
studies become an important source of information for the understanding of
biomechanical events on implantsupported prostheses, although study results cannot
be considered reliable unless validation studies are conducted. The purpose of
this work was to validate an artificial experimental model based on its modulus of
elasticity, to simulate the performance of human bone in vivo in
biomechanical studies of implant-supported prostheses. Material and Methods In this study, fast-curing polyurethane (F16 polyurethane, Axson) was used to
build 40 specimens that were divided into five groups. The following reagent
ratios (part A/part B) were used: Group A (0.5/1.0), Group B (0.8/1.0), Group C
(1.0/1.0), Group D (1.2/1.0), and Group E (1.5/1.0). A universal testing machine
(Kratos model K – 2000 MP) was used to measure modulus of elasticity values by
compression. Results Mean modulus of elasticity values were: Group A – 389.72 MPa, Group B – 529.19
MPa, Group C – 571.11 MPa, Group D – 470.35 MPa, Group E – 437.36 MPa. Conclusion The best mechanical characteristics and modulus of elasticity value comparable to
that of human trabecular bone were obtained when A/B ratio was 1:1.
Collapse
|
200
|
The effects of the periodontal ligament on mandibular stiffness: a study combining finite element analysis and geometric morphometrics. J Biomech 2011; 44:1304-12. [PMID: 21292267 DOI: 10.1016/j.jbiomech.2011.01.008] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2010] [Revised: 01/06/2011] [Accepted: 01/07/2011] [Indexed: 11/22/2022]
Abstract
It is generally accepted that the periodontal ligament (PDL) plays a crucial role in transferring occlusal forces from the teeth to the alveolar bone. Studies using finite element analysis (FEA) have helped to better understand this role and show that the stresses and strains in the alveolar bone are influenced by whether and how PDL is included in FE models. However, when the overall distribution of stresses and strains in crania and mandibles are of interest, PDL is often not included in FE models, although little is known about how this affects the results. Here we study the effect of representing PDL as a layer of solid material with isotropic homogeneous properties in an FE model of a human mandible using a novel application of geometric morphometrics. The results show that the modelling of the PDL affects the deformation and thus strain magnitudes not only of the alveolar bone around the biting tooth, but that the whole mandible deforms differently under load. As a result, the strain in the mandibular corpus is significantly increased when PDL is included, while the strain in the bone beneath the biting tooth is reduced. These results indicate the importance of the PDL in FE studies. Thus we recommend that the PDL should be included in FE models of the masticatory apparatus, with tests to assess the sensitivity of the results to changes in the Young's modulus of the PDL material.
Collapse
|