scholarly journals Histological Evidence of the Osseointegration of Fractured Direct Metal Laser Sintering Implants Retrieved after 5 Years of Function

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Francesco Mangano ◽  
Carlo Mangano ◽  
Adriano Piattelli ◽  
Giovanna Iezzi
Keyword(s):  
Close Contact ◽  
Laser Sintering ◽  
Laser Fusion ◽  
Layer By Layer ◽  
Direct Metal Laser Sintering ◽  
Implant Surface ◽  
Histomorphometric Study ◽  
Bone To Implant Contact ◽  
Functional Loading

Background. Direct metal laser sintering (DMLS) is an additive manufacturing technique that allows the fabrication of dental implants layer by layer through the laser fusion of titanium microparticles. The surface of DMLS implants is characterized by a high open porosity with interconnected pores of different sizes; therefore, it has the potential to enhance and accelerate bone healing. To date, however, there are no histologic/histomorphometric studies in the literature evaluating the interface between bone and DMLS implants in the long-term. Purpose. To evaluate the interface between bone and DMLS implants retrieved after 5 years of functional loading. Methods. Two fractured DMLS implants were retrieved from the human jaws, using a 5 mm trephine bur. Both the implants were clinically stable and functioned regularly before fracture. The specimens were processed for histologic/histomorphometric evaluation; the bone-to-implant contact (BIC%) was calculated. Results. Compact, mature lamellar bone was found over most of the DMLS implants in close contact with the implant surface; the histomorphometric evaluation showed a mean BIC% of 66.1% (±4.5%). Conclusions. The present histologic/histomorphometric study showed that DMLS implants were well integrated in bone, after 5 years of loading, with the peri-implant bone undergoing continuous remodeling at the interface.

Evaluation of Peri-Implant Bone Response in Implants Retrieved for Fracture After More Than 20 Years of Loading: A Case Series

2015 ◽  
Vol 41 (4) ◽  
pp. 414-418 ◽  
Author(s):  
Carlo Mangano ◽  
Adriano Piattelli ◽  
Carmen Mortellaro ◽  
Francesco Mangano ◽  
Vittoria Perrotti ◽  
...  
Keyword(s):  
Close Contact ◽  
Case Series ◽  
Compact Bone ◽  
Implant Surface ◽  
Bone Response ◽  
Histological Data ◽  
Maturation Stages ◽  
Bone To Implant Contact ◽  
The University

Analysis of human retrieved dental implants is a useful tool in the evaluation of implant success and failure. More human histological data are needed from samples of long-term implant service. The aim of the present case series was a histological and histomorphometrical evaluation of the peri-implant bone responses in implants retrieved for fracture after more than 20 years loading. The archives of the Implant Retrieval Center of the Department of Medical, Oral and Biotechnological Sciences of the University of Chieti-Pescara, Italy were searched. A total of 5 implants, retrieved after a loading period of more than 20 years, were found: 2 had been retrieved after 20 years, 1 after 22 years, 1 after 25 years, and 1 after 27 years. All these implants were histologically processed. Compact, mature bone in close contact with the implant surface was observed in all specimens, with no gaps or connective tissue at the interface. Bone in different maturation stages was found around some implants. Primarily newly formed bone was observed in proximity of the implant surface, while mature compact bone with many remodeling areas and cement lines were detected in areas distant from the implant. Many primary and secondary osteons were present. Bone to implant contact percentage varied from 37.2% to 76%. In conclusion, histology and histomorphometry showed that even after many years of function, all implants presented more than adequate bone to implant contact and they appeared to be very well integrated in the peri-implant bone.

scholarly journals Maxillary Overdentures Supported by Four Splinted Direct Metal Laser Sintering Implants: A 3-Year Prospective Clinical Study

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Francesco Mangano ◽  
Fabrizia Luongo ◽  
Jamil Awad Shibli ◽  
Sukumaran Anil ◽  
Carlo Mangano
Keyword(s):  
Bone Loss ◽  
Laser Sintering ◽  
Titanium Implants ◽  
Prospective Clinical Study ◽  
Implant Survival ◽  
Direct Metal Laser Sintering ◽  
Marginal Bone Loss ◽  
Bone Level ◽  
Bone To Implant Contact

Purpose. Nowadays, the advancements in direct metal laser sintering (DMLS) technology allow the fabrication of titanium dental implants. The aim of this study was to evaluate implant survival, complications, and peri-implant marginal bone loss of DMLS implants used to support bar-retained maxillary overdentures.Materials and Methods. Over a 2-year period, 120 implants were placed in the maxilla of 30 patients (18 males, 12 females) to support bar-retained maxillary overdentures (ODs). Each OD was supported by 4 implants splinted by a rigid cobalt-chrome bar. At each annual follow-up session, clinical and radiographic parameters were assessed. The outcome measures were implant failure, biological and prosthetic complications, and peri-implant marginal bone loss (distance between the implant shoulder and the first visible bone-to-implant contact, DIB).Results. The 3-year implant survival rate was 97.4% (implant-based) and 92.9% (patient-based). Three implants failed. The incidence of biological complication was 3.5% (implant-based) and 7.1% (patient-based). The incidence of prosthetic complication was 17.8% (patient-based). No detrimental effects on marginal bone level were evidenced.Conclusions. The use of 4 DMLS titanium implants to support bar-retained maxillary ODs seems to represent a safe and successful procedure. Long-term clinical studies on a larger sample of patients are needed to confirm these results.

Effect of Build Direction in Direct Metal Laser Sintering (DMLS) of Inconel 718 on Microstructure and Mechanical Behavior

2019 ◽  
Author(s):  
Sachin Alya ◽  
Chaitanya Vundru ◽  
Ramesh Singh ◽  
Khushahal Thool ◽  
Indradev Samajdar ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Mechanical Behavior ◽  
Inconel 718 ◽  
Laser Sintering ◽  
Thermal Gradients ◽  
Layer By Layer ◽  
Direct Metal Laser Sintering ◽  
Powder Bed ◽  
Grain Orientations ◽  
End Use

Abstract Additive manufacturing (AM) technology is gaining enormous popularity in the manufacturing industries. The continuous improvements made in the AM processes features development of 3D metallic prototypes as well as fully functional end-use components. Direct Metal Laser Sintering (DMLS) is a pre-placed powder bed based technique, in which a thin layer of powder is place over the build tray and the areas need to be sintered are exposed to the laser. In the current work the microstructural and mechanical behavior of Inconel 718 parts produced by DMLS are investigated. As the DMLS produces parts in a layer by layer fashion, the orientation of parts with respect to the build direction is an important criterion. Microstructure and mechanical properties of the produce differs depending upon the orientation. This paper emphasize on the variation of grain sizes and grain orientations developed in the components built with different orientations. Another common issue with the additive manufacturing is the development of the residual stresses in the components arising due to the differential thermal gradients experienced during processing. The variation of the residual stress generated in the produced parts has also been characterized and modeled.

Influence of the Direct Metal Laser Sintering Process on the Fatigue Behavior of the Ti6Al4V Alloy

2017 ◽  
Vol 891 ◽  
pp. 317-321 ◽  
Author(s):  
Adrián Bača ◽  
Radomila Konečná ◽  
Gianni Nicoletto
Keyword(s):  
Additive Manufacturing ◽  
Process Parameters ◽  
Fatigue Behavior ◽  
Laser Sintering ◽  
Ti6al4v Alloy ◽  
Process Conditions ◽  
Layer By Layer ◽  
Metal Powders ◽  
Direct Metal Laser Sintering ◽  
Post Process

Direct Metal Laser Sintering (DMLS) is additive manufacturing (AM) process that can produce near net shape parts from metal powders such as titanium alloys. DMLS is a layer by layer additive manufacturing technique based on high power fiber laser that creates solid layers from loose powder material and joins them in an additive manner. The specific DMLS process conditions, lead to a specific and complex microstructure and to mechanical properties that show a degree of directionality. It was found that microstructural characteristics are related to the building process parameters. The aim of this work is to evaluate the fatigue performance of the Ti6Al4V alloy depending on the process parameters, building orientations and post-process heat treatment.

Human Histologic Evaluation of a Six-year-old Threaded Implant Retrieved from a Subject with Osteoporosis

2008 ◽  
Vol 9 (3) ◽  
pp. 99-105 ◽  
Author(s):  
Adriano Piattelli ◽  
Jamil A. Shibli ◽  
Leandro de Melo ◽  
Giovanna Lezzi ◽  
Susana d'Avila ◽  
...  
Keyword(s):  
Alveolar Bone ◽  
Close Contact ◽  
Human Life ◽  
Elderly Subjects ◽  
Implant Surface ◽  
Implant Placement ◽  
Histologic Evaluation ◽  
Bone To Implant Contact ◽  
The Mean ◽  
Cement Lines

Abstract Aim The aim of this case report was to present the evaluation of the bone-to-implant contact in an implant retrieved from a subject with osteoporosis after six years of load. Background Systemic conditions associated with osteoporosis have been postulated to contribute to the severity of alveolar bone loss. The increase in human life expectancy, the increased number of elderly subjects who are partially or totally edentulous, and the use of dental implants for oral habilitation in subjects with osteoporosis has raised several questions. Report A 68-year-old woman with postmenopausal osteoporosis received a prosthetic evaluation of an implant-supported restoration. Histologically, the peri-implant bone appeared healthy. The peri-implant bone appeared in close contact with the implant surface, whereas marrow spaces could be detected in other areas along with prominently stained cement lines. The mean of bone-to-implant contact was 62.51±1.96. Conclusion The results of the evaluation of the dental implant reported here suggest the presence of osteoporosis may not be a contra-indication for implant placement at least after osseointegration has already been established. Citation de Melo L, Piattelli A, Lezzi G, d'Avila S, Zenóbio EG, Shibli JA. Human Histologic Evaluation of a Six-year-old Threaded Implant Retrieved from a Subject with Osteoporosis. J Contemp Dent Pract 2008 March; (9)3:099-105.

Study of Condensate Generated During Direct Metal Laser Sintering

2017 ◽  
Author(s):  
Jagadish Chandra Achinadka
Keyword(s):  
Maraging Steel ◽  
Laser Sintering ◽  
Steel Grade ◽  
Process Efficiency ◽  
Layer By Layer ◽  
Direct Metal Laser Sintering ◽  
Additive Manufacturing Technology ◽  
High Intensity Laser ◽  
Xrd Studies ◽  
Intensity Laser

DMLS (Direct Metal Laser Sintering), an additive manufacturing technology, is increasingly becoming popular to build intricate high quality functional parts & rapid prototypes. DMLS technology uses a high intensity laser to build components layer by layer, directly from metal powder. CAD data is directly converted to part without the need for tooling. It is possible to build internal features and passages that are not possible in conventional manufacturing routes. The process generates significant amount of condensate due to vaporization and suction applied to build chamber. Typically as much as 30% of the weight of powder ends up as condensate. The condensate so generated cannot be directly recycled. This results in significant reduction in profitability and process efficiency. This study pertains to 18% Ni Maraging Steel grade C300, which commonly used in DMLS process. Maraging Steel is used extensively to build functional parts by DMLS process especially for Tool and Die applications. In the present study chemistry, particle size distribution & morphology of the condensate was studied & compared with the powder. Parts were built using condensate and chemical, physical, mechanical, microstructure and XRD studies were done. These properties were compared with properties of parts built using fresh powder. No difficulty was encountered in building parts using condensate. However, hardness and tensile properties were found to be inferior, thus it is not possible to recycle the condensate directly. Present research investigates the cause of difference in these properties.

STUDY OF THE PROPERTIES A FRAGMENT OF THE HYDRAULIC CIRCUIT OF THE SPACECRAFT, OBTAINED BY MEANS OF ADDITIVE TECHNOLOGIES

2020 ◽  
pp. 11-19
Author(s):  
I. E. Mal’tzev ◽  
A. A. Basov ◽  
M. A. Borisov ◽  
A. V. Bystrov
Keyword(s):  
Selective Laser Melting ◽  
Experimental Work ◽  
Heat Exchangers ◽  
Selective Laser Sintering ◽  
Laser Sintering ◽  
Additive Technologies ◽  
Laser Fusion ◽  
Layer By Layer ◽  
Laser Melting ◽  
Hydraulic Circuits

The article discusses the course and results of experimental work on the initial study of the possibility of using one of the varieties of additive technologies – the method of layer-by-layer selective laser melting (SLM) in the manufacture of elements of heat exchangers and hydraulic circuits of spacecraft. Traditional manufacturing techniques for hydro-control elements and spacecraft heat exchangers are based on machining and high-temperature vacuum soldering, leading to a long cycle and high manufacturing costs. As an alternative, the method of layer-by-layer selective laser melting can be considered as a manufacturing method using a three-dimensional model of the product and not requiring additional equipment. This method is based on sequential layer-by-layer fusion of a metal powder with previous fused product layers under the action of a laser beam forming a local region of liquid melt. The article describes experimental work to assess the possibility of using the selective laser melting method. Assessed weld-ability of a sample made by selective laser fusion technology with tips made by traditional technology. Directions for testing the method of selective laser sintering on real structures of heat exchanging units of spacecraft have been determined. A technique is proposed and the results of a study of a sample synthesized by selective laser sintering are presented. Based on the results obtained, an analysis is made of the prospects for using this method in the production of elements of hydraulic circuits and heat exchange units of spacecraft.

Effect of Cryogenic Treatment on the Mechanical Properties of 18Ni-300 Grade Maraging Steel Built Using the Direct Metal Laser Sintering (DMLS) Technology

2016 ◽  
Vol 719 ◽  
pp. 114-121 ◽  
Author(s):  
C.A. Jagadish ◽  
Nadig Priyanka
Keyword(s):  
Mechanical Properties ◽  
Maraging Steel ◽  
Cryogenic Treatment ◽  
High Strength ◽  
Laser Sintering ◽  
Pressure Vessels ◽  
Layer By Layer ◽  
Direct Metal Laser Sintering ◽  
Maraging Steels ◽  
High Intensity Laser

Maraging steels belong to the class of steels that are found to have a unique combination of ultra-high strength and good fracture toughness, due to which they find uses in critical applications such as aircraft forgings, pressure vessels, missile casings, hydraulic hoses etc. Several studies on the effect of cryogenic treatment on various grades of Tool steels & Maraging steels have shown significant improvements in mechanical properties and dimensional stability.DMLS (Direct Metal Laser Sintering), an additive manufacturing technology, is increasingly becoming popular to build intricate high quality functional parts & rapid prototypes. DMLS technology uses a high intensity laser to build components layer by layer, directly from CAD data without the need for tooling. It is possible to build internal features and passages that are not possible in conventional manufacturing routes. Maraging Steel is used extensively to build functional parts by DMLS process especially for Tool and Die applications. However, very few findings have been reported on the effect of cryogenic treatment on the mechanical properties of Maraging steel built through this route. In this study, effect of cryogenic treatment on Maraging Steel grade 300 built by DMLS process is discussed. Test specimens were built in horizontal and vertical directions to see the effect of build direction on the properties. Half the specimens were given standard DMLS precipitation hardening heat treatment and the rest were given cryogenic treatment in addition to routine thermal treatment. Mechanical properties such as - tensile, impact properties , hardness, & density between the two sets of treatments are reported and discussed. Metallurgical structures are compared and findings are also reported.

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