scholarly journals Augmentation of DMLS Biomimetic Dental Implants with Weight-Bearing Strut to Balance of Biologic and Mechanical Demands: From Bench to Animal

Materials ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 164 ◽  
Author(s):  
Jenny Zwei-Chieng Chang ◽  
Pei-I Tsai ◽  
Mark Yen-Ping Kuo ◽  
Jui-Sheng Sun ◽  
San-Yuan Chen ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Dental Implants ◽  
Dental Implant ◽  
Bone Ingrowth ◽  
Weight Bearing ◽  
Morphological Characteristics ◽  
Porous Scaffolds ◽  
Pull Out ◽  
Mg63 Cells

A mismatch of elastic modulus values could result in undesirable bone resorption around the dental implant. The objective of this study was to optimize direct metal laser sintering (DMLS)-manufactured Ti6Al4V dental implants’ design, minimize elastic mismatch, allow for maximal bone ingrowth, and improve long-term fixation of the implant. In this study, DMLS dental implants with different morphological characteristics were fabricated. Three-point bending, torsional, and stability tests were performed to compare the mechanical properties of different designs. Improvement of the weaker design was attempted by augmentation with a longitudinal 3D-printed strut. The osseointegrative properties were evaluated. The results showed that the increase in porosity decreased the mechanical properties, while augmentation with a longitudinal weight-bearing strut can improve mechanical strength. Maximal alkaline phosphatase gene expression of MG63 cells attained on 60% porosity Ti6Al4V discs. In vivo experiments showed good incorporation of bone into the porous scaffolds of the DMLS dental implant, resulting in a higher pull-out strength. In summary, we introduced a new design concept by augmenting the implant with a longitudinal weight-bearing strut to achieve the ideal combination of high strength and low elastic modulus; our results showed that there is a chance to reach the balance of both biologic and mechanical demands.

Fabrication and Mechanical Properties of Dense/Porous β-Tricalcium Phosphate Bioceramics

2007 ◽  
Vol 330-332 ◽  
pp. 907-910
Author(s):  
Fa Ming Zhang ◽  
Jiang Chang ◽  
Jian Xi Lu ◽  
Kai Li Lin
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Elastic Modulus ◽  
Exponential Growth ◽  
Weight Bearing ◽  
Area Ratio ◽  
Sectional Area ◽  
Cross Sectional ◽  
The Matrix ◽  
Porous Bioceramics

Attempt to increase the mechanical properties of porous bioceramics, a dense/porous structured β-TCP bioceramics that mimic the characteristics of nature bone were fabricated. Experimental results show that the dense/porous structured β-TCP bioceramics demonstrated excellent mechanical properties with compressive strength up to 74 MPa and elastic modulus up to 960 MPa, which could be tailored by the dense/porous cross-sectional area ratio obeying the rule of exponential growth. The interface between the dense and porous bioceramics is connected compactly and tightly with some micropores distributed in the matrix of both porous and dense counterparts. The dense/porous structure of β-TCP bioceramics may provide an effective way to increase the mechanical properties of porous bioceramics for bone regeneration at weight bearing sites.

scholarly journals Experimental Investigation into the Effect of Surface Roughness and Mechanical Properties of 3D-Printed Titanium Ti-64 ELI after Heat Treatment

2021 ◽  
Author(s):  
Lebogang Lebea ◽  
Harry M Ngwangwa ◽  
Dawood Desai ◽  
Fuluphelo Nemavhola
Keyword(s):  
Mechanical Properties ◽  
Surface Roughness ◽  
Dental Implants ◽  
Dental Implant ◽  
Complex Geometry ◽  
Poor Performance ◽  
Vital Role ◽  
Ultimate Tensile Stress ◽  
3D Printed ◽  
Effect Of Surface

The initial stability after implantology is paramount to the survival of the dental implant and the surface roughness of the implant plays a vital role in this regard. The characterisation of surface topography is a complicated branch of metrology, with a huge range of parameters available. Each parameter contributes significantly towards the survival and mechanical properties of 3D-printed specimens. The purpose of this paper is to experimentally investigate the effect of surface roughness of 3D-printed dental implants and 3D-printed dogbone tensile samples under areal height (Ra) parameters, amplitude parameters (average of ordinates), skewness (Rsk) parameters and mechanical properties. During the experiment, roughness values were analysed and the results showed that the skewness parameter demonstrated a minimum value of 0.596%. The 3D-printed dental implant recorded Ra with a 3.4 mm diameter at 43.23% and the 3D-printed dental implant with a 4.3 mm diameter at 26.18%. Samples with a complex geometry exhibited a higher roughness surface, which was the greatest difficulty of additive manufacturing when evaluating surface finish. The results show that when the ultimate tensile stress (UTS) decreases from 968.35 MPa to 955.25 MPa, Ra increases by 1.4% and when UTS increases to 961.18 MPa, Ra increases by 0.6%. When the cycle decreases from 262142 to 137433, Ra shows that less than a 90.74% increase in cycle is obtained. For 3D-printed dental implants, the higher the surface roughness, the lower the mechanical properties, ultimately leading to decreased implant life and poor performance.

scholarly journals Bioactivity and Bone Cell Formation with Poly-ε-Caprolactone/Bioceramic 3D Porous Scaffolds

Polymers ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2718
Author(s):  
Po-Kai Juan ◽  
Fang-Yu Fan ◽  
Wei-Chun Lin ◽  
Pei-Bang Liao ◽  
Chiung-Fang Huang ◽  
...  
Keyword(s):  
Elastic Modulus ◽  
Cell Attachment ◽  
Ph Value ◽  
Ceramic Powder ◽  
High Ratio ◽  
Porous Scaffolds ◽  
Alp Activity ◽  
Mg63 Cells ◽  
Human Cancellous Bone

This study applied poly-ε-caprolactone (PCL), a biomedical ceramic powder as an additive (nano-hydroxyapatite (nHA) or β-tricalcium diphosphate (β-TCP)), and sodium chloride (NaCl) and ammonium bicarbonate ((NH4)HCO3) as porogens; these stuffs were used as scaffold materials. An improved solvent-casting/particulate-leaching method was utilized to fabricate 3D porous scaffolds. In this study we examined the physical properties (elastic modulus, porosity, and contact angle) and degradation properties (weight loss and pH value) of the 3D porous scaffolds. Both nHA and β-TCP improved the mechanical properties (elastic modulus) of the 3D porous scaffolds. The elastic modulus (0.15~1.865 GPa) of the various composite scaffolds matched that of human cancellous bone (0.1~4.5 GPa). Osteoblast-like (MG63) cells were cultured, a microculture tetrazolium test (MTT) was conducted and alkaline phosphatase (ALP) activity of the 3D porous scaffolds was determined. Experimental results indicated that both nHA and β-TCP powder improved the hydrophilic properties of the scaffolds. The degradation rate of the scaffolds was accelerated by adding nHA or β-TCP. The MTT and ALP activity tests indicated that the scaffolds with a high ratio of nHA or β-TCP had excellent properties of in vitro biocompatibility (cell attachment and proliferation).

scholarly journals Analysis of Mechanical Properties and Permeability of Trabecular-Like Porous Scaffold by Additive Manufacturing

2021 ◽  
Vol 9 ◽  
Author(s):  
Long Chao ◽  
Chen Jiao ◽  
Huixin Liang ◽  
Deqiao Xie ◽  
Lida Shen ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Bone Repair ◽  
Bone Cells ◽  
Porous Scaffold ◽  
Bone Ingrowth ◽  
Voronoi Tessellation ◽  
Stress Shielding ◽  
Porous Scaffolds ◽  
Porous Structures ◽  
Element Analysis

Human bone cells live in a complex environment, and the biomimetic design of porous structures attached to implants is in high demand. Porous structures based on Voronoi tessellation with biomimetic potential are gradually used in bone repair scaffolds. In this study, the mechanical properties and permeability of trabecular-like porous scaffolds with different porosity levels and average apertures were analyzed. The mechanical properties of bone-implant scaffolds were evaluated using finite element analysis and a mechanical compression experiment, and the permeability was studied by computational fluid dynamics. Finally, the attachment of cells was observed by confocal fluorescence microscope. The results show that the performance of porous structures can be controlled by the initial design of the microstructure and tissue morphology. A good structural design can accurately match the performance of the natural bone. The study of mechanical properties and permeability of the porous structure can help address several problems, including stress shielding and bone ingrowth in existing biomimetic bone structures, and will also promotes cell adhesion, migration, and eventual new bone attachment.

scholarly journals Additively Manufactured Continuous Cell-Size Gradient Porous Scaffolds: Pore Characteristics, Mechanical Properties and Biological Responses In Vitro

Materials ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2589 ◽  
Author(s):  
Fei Liu ◽  
Qichun Ran ◽  
Miao Zhao ◽  
Tao Zhang ◽  
David Z. Zhang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Pore Size ◽  
Cell Size ◽  
Porous Scaffolds ◽  
Ct Reconstruction ◽  
Pore Characteristics ◽  
Growth Environment ◽  
Size Gradient

Porous scaffolds with graded open porosity combining a morphology similar to that of bone with mechanical and biological properties are becoming an attractive candidate for bone grafts. In this work, scaffolds with a continuous cell-size gradient were studied from the aspects of pore properties, mechanical properties and bio-functional properties. Using a mathematical method named triply periodic minimal surfaces (TPMS), uniform and graded scaffolds with Gyroid and Diamond units were manufactured by selective laser melting (SLM) with Ti-6Al-4V, followed by micro-computer tomography (CT) reconstruction, mechanical testing and in vitro evaluation. It was found that gradient scaffolds were preferably replicated by SLM with continuous graded changes in surface area and pore size, but their pore size should be designed to be ≥ 450 μm to ensure good interconnectivity. Both the Gyroid and Diamond structures have superior strength compared to cancellous bones, and their elastic modulus is comparable to the bones. In comparison, Gyroid exhibits better performances than Diamond in terms of the elastic modulus, ultimate strength and ductility. In vitro cell culture experiments show that the gradients provide an ideal growth environment for osteoblast growth in which cells survive well and distribute uniformly due to biocompatibility of the Ti-6Al-4V material, interconnectivity and suitable pore size.

scholarly journals Development of a radiographic dental implant guide for identification of dental implant types

2020 ◽  
Vol 75 (8) ◽  
pp. 432-437
Author(s):  
Lisa Vermeulen ◽  
Aladdin Speelman ◽  
Valdiela Daries ◽  
Vincent Philips
Keyword(s):  
Dental Implants ◽  
Dental Implant ◽  
Health Care Professionals ◽  
Initial Point ◽  
Morphological Characteristics ◽  
Straight Tube ◽  
Western Cape ◽  
Accurate Identification ◽  
Reference Instrument ◽  
Dental Anatomy

INTRODUCTION: Identification of dental implant types can be a complex process for inexperienced health care professionals. Dental implants can have subtle differences in their morphology, which make it difficult to distinguish them from one another The unique appearance of dental anatomy and the placement of custom restorations ensure accurate identification of bodies or human remains when radiographic techniques are correctly applied. AIMS AND OBJECTIVES: To develop a radiographic dental implant guide for ten common dental implant types currently used in the Western Cape, South Africa; using their morphological characteristics observed on pantomographs. DESIGN: The methodology considered for this research study was a positivist approach through a quantitative, exploratory, non-experimental research design. METHODS: Ten commonly used dental implants were radiographed at straight tube (ST), off-centre (OC) and severe off-centre (SOC) angles to create a reference instrument Two reviewers used the morphologies of the different dental implant types, namely the apex, thread and neck, observed on ante-mortem pantomographs, and compared it to the appearance of the dental implants in the reference instrument to make a positive identification match. The straight tube image of all ten dental implant types in the reference instrument was used as the initial point of reference to positively identify the morphological characteristics of each dental implant type on the pantomographs. RESULTS: A total of 380 dental implants could be identified on 105 pantomographs reviewed. Of the 380 dental implants, 350 dental implants (91%) were identified as dental implant types listed in the reference instrument while 30 dental implants were identified as another type of dental implant type not listed in the reference instrument A total of 208 dental implants (54.2%) could be positively identified on the ante-mortem pantomographs using the straight tube images in the reference instrument. The morphological characteristics of the dental implant types were described using x-ray imaging of dental implants. The ten commonly used dental implants types could be positively identified by two independent reviewers and based on this a radiographic dental implant guide was developed. CONCLUSION: Each dental implant type had unique morphological characteristics as well as similarities which enabled distinction between the different dental implant types. The dental implant guide developed could be used by dentistry and radiography students. The dental implant guide may be useful in the field of forensic dentistry and forensic radiology.

scholarly journals Investigation of Mechanical and Biological Properties of FDM 3D-Printed PLA Scaffolds With Radial Gradient Porosity for Tissue Engineering

2021 ◽  
Author(s):  
Meltem Eryildiz
Keyword(s):  
Mechanical Properties ◽  
Tissue Engineering ◽  
Fused Deposition Modeling ◽  
Bone Ingrowth ◽  
Biological Properties ◽  
Porous Scaffolds ◽  
Radial Gradient ◽  
Fused Deposition ◽  
Novel Approach

Abstract Scaffolds with gradient porosity have become very promising candidates for tissue engineering and bone implants because of the combination of better mechanical and biological requirements. In this paper, a novel approach is proposed to design bone scaffolds with gradient porosity similar to the structure of cortical and spongy (cancellous) bones. The radial gradient PLA scaffolds were designed to consist of three different regions with the gyroid infill and, fabricated by Fused deposition modeling (FDM). The biological and mechanical properties of the scaffolds were investigated in vitro. Dense scaffold (G100) had improved mechanical properties but showed decreased bone ingrowth properties. In addition, porous scaffolds provided enhanced biological properties but decreased in mechanical strength (G40-G20). The scaffolds with radial gradient porosity (G100-40-20) gave highest cell proliferation. Because, mean pore size is an important aspect of scaffolds for mimicking bone.

scholarly journals 3D Printing of Macro Porous Sol-Gel Derived Bioactive Glass Scaffolds and Assessment of Biological Response

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 5946
Author(s):  
Ricardo Bento ◽  
Anuraag Gaddam ◽  
Párástu Oskoei ◽  
Helena Oliveira ◽  
José M. F. Ferreira
Keyword(s):  
Mechanical Properties ◽  
3D Printing ◽  
Bioactive Glass ◽  
Bone Ingrowth ◽  
Sol Gel ◽  
Biological Response ◽  
Treatment Temperature ◽  
Bone Tissue Regeneration ◽  
Porous Scaffolds ◽  
Potential Game

3D printing emerged as a potential game-changer in the field of biomedical engineering. Robocasting in particular has shown excellent capability to produce custom-sized porous scaffolds from pastes with suitable viscoelastic properties. The materials and respective processing methods developed so far still need further improvements in order to obtain completely satisfactory scaffolds capable of providing both the biological and mechanical properties required for successful and comprehensive bone tissue regeneration. This work reports on the sol-gel synthesis of an alkali-free bioactive glass and on its characterization and processing ability towards the fabrication of porous scaffolds by robocasting. A two-fold increase in milling efficiency was achieved by suitably adjusting the milling procedures. The heat treatment temperature exerted a profound effect on the surface area of mesoporous powders. Robocasting inks containing 35 vol.% solids were prepared, and their flow properties were characterized by rheological tests. A script capable of preparing customizable CAD scaffold geometries was developed. The printing process was adjusted to increase the technique’s resolution. The mechanical properties of the scaffolds were assessed through compressive strength tests. The biomineralization ability and the biological performance were assessed by immersing the samples in simulated body fluid (SBF) and through MTT assays, respectively. The overall results demonstrated that scaffolds with macro porous features suitable for bone ingrowth (pore sizes of ~340 mm after sintering, and a porosity fraction of ~70%) in non-load-bearing applications could be successfully fabricated by 3D printing from the bioactive glass inks. Moreover, the scaffolds exhibited good biomineralization activity and good biocompatibility with human keratinocytes, suggesting they are safe and thus suited for the intended biomedical applications.

scholarly journals Experimental Researchon Properties of High Strength Concrete (Hybrid)

2019 ◽  
Vol 8 (6S4) ◽  
pp. 267-268
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
High Strength Concrete ◽  
Fracture Resistance ◽  
Considerable Increase ◽  
High Strength ◽  
Pull Out ◽  
Hybrid Fibre ◽  
Short Fibres ◽  
The Individual

Hybrid Fibre ferroconcrete a composite may be termed as a hybrid two or additional kinds of fibres are combined during a common matrix provide composite that drives advantage from each of the individual fibres and Exhibits a synergetic response. Addition of short fibres plays a crucial role in the improvement of mechanical properties. It will increase elastic modulus decreases crispness controls cracks initiation and its resultant Growth and propagation. Deboning and pull out of the fibre need a lot of energy absorption, leading to a considerable increase within the toughness and fracture resistance of the materials to the cyclic and dynamic hundreds

Mechanical properties and osteoblast proliferation of complex porous dental implants filled with magnesium alloy based on 3D printing

2020 ◽  
pp. 088532822095790
Author(s):  
Xuetao Zhang ◽  
Jian Mao ◽  
Yufeng Zhou ◽  
Fangqiu Ji ◽  
Xianshuai Chen
Keyword(s):  
Mechanical Properties ◽  
Magnesium Alloy ◽  
3D Printing ◽  
Porous Structure ◽  
Dental Implants ◽  
Dental Implant ◽  
Alveolar Bone ◽  
Element Analysis ◽  
Weak Part

In this paper, a complex porous dental implant with biodegradable magnesium alloy was designed based on selective laser melting (SLM). Finite element analysis (FEA) was used to simulate the stress distribution of dental implant and alveolar bone in two models of preliminary and later stages of implant. The stress concentration area of dental implants was found not in the porous structure, and the weak part of mechanical properties accords with the work requirements. The porous structure of dental implants can promote the function of cancellous bone in the process of conducting the stress of the dental implant, thus improving the bearing capacity of dental implants. In vitro fatigue experiments were carried out on the experimental samples produced by 3D printing. Through the cell contrast experiment, it was proved that the decomposed Mg2+ could reach the titanium surface smoothly through the porous structure and complete the proliferation of osteoblasts.

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