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1.
Article in Spanish | LILACS-Express | LILACS | ID: biblio-1385236

ABSTRACT

RESUMEN: La rehabilitación de rebordes severamente atróficos mediante prótesis híbridas con subestructura cromo-cobalto fabricadas por sinterizado láser asegura el ajuste pasivo, aumentando la estabilidad de los tejidos de soporte a largo plazo. Los controles periódicos y enseñanza de técnicas de higiene son fundamentales para el éxito de rehabilitaciones complejas sobre implantes. El propósito de este reporte de caso es realizar la evaluación clínica y radiográfica a 5 años de prótesis híbridas maxilar y mandibular fabricadas mediante sinterizado láser, encontrándose resultados satisfactorios en la evaluación y seguimiento.


ABSTRACT: Rehabilitation of severely atrophic ridges using hybrid cobalt-chrome substructures manufactured by laser sintering ensures passive fit, increasing support tissue stability. Regular check-ups and the teaching of hygiene techniques are essential for the success of complex implant restorations. The purpose of this case report is to perform a 5-year clinical and radiographic evaluation of hybrid maxillary and mandibular prostheses manufactured using laser sintering, achieving satisfactory results in the evaluation and follow-up.

2.
Journal of Medical Biomechanics ; (6): E264-E270, 2021.
Article in Chinese | WPRIM | ID: wpr-904396

ABSTRACT

Objective To make finite element analysis and compressive performance test on three-dimensional (3D) printed personalized poly-ether-ether-ketone (PEEK) condyle prosthesis, so as to analyze stress distribution characteristics and mechanical properties of the prosthesis, and to evaluate its clinical value and prospect. Methods The finite element models of PEEK condyle prosthesis, mandible and fixation screw were established by software such as CBCT, Mimics, Geomagic Studio, SolidWorks and ANSYS Workbench. The maximum mastication force was applied, and the maximum stress of the condyle prosthesis and screw, as well as the stress and strain of the mandible were recorded. In order to simulate the actual clinical situation, a special fixture was designed to test compression performance of the condyle prosthesis prepared by the fused deposition modeling (FDM) and selective laser sintering (SLS) at the rate of 1 mm/min. Results The peak stress of the PEEK condyle prosthesis was 10.733 MPa, which was located at the back of the condyle neck. The peak stress of 5 fixing screws was 9.707 5 MPa, which appeared on the 2# and 5# screws near the trailing edge of the mandibular ascending branch. The peak stress of both the prosthesis and the screw was smaller than its yield strength. The maximum pressure of the condyle prosthesis prepared by FDM and SLS was (3 814.7±442.6) N and (1 193.970±260.350) N, respectively. Compared with the SLS preparation, the FDM prepared prosthesis not only had higher compression strength but also better toughness. Conclusions The 3D printed personalized PEEK condyle prosthesis shows uniform stress distributions and good mechanical properties, which can provide the theoretical basis for PEEK as reconstruction material for repairing temporomandibular joint.

3.
Chinese Journal of Tissue Engineering Research ; (53): 637-642, 2020.
Article in Chinese | WPRIM | ID: wpr-848151

ABSTRACT

BACKGROUND: In the case of tooth defect or missing, the treatment should be achieved by making a personalized prosthesis. Traditional manufacturing process is time-consuming, costly and accurate. After the introduction of 3D printing technology into dental manufacture, the manufacturing efficiency and quality can be improved to a certain extent. OBJECTIVE: To introduce the application of 3D printing technology in dental manufacture, discuss the bottleneck in recent application, and guide the development of 3D printing technology in dental manufacture. METHODS: The authors used the search times "3D printing, metal implant, dental manufacturing, dental restorations” to search Web of Science, Wanfang, CNKI databases in English and Chinese separately to search papers published during 1980-2019. 261 papers were preliminarily retrieved and 60 of them were included in the final analysis. RESULTS AND CONCLUSION: 3D printing dental mold, digital implant guide plate and wax pattern have been widely used in dental manufacture. 3D printing technology has been widely used in dental manufacture. The most widely used six processes are stereo lithography appearance, laminated object manufacturing, fused deposition modeling, selective laser sintering, selective laser melting, and inkjet printing. There are some technical bottlenecks in the application of 3D printing technology in the field of dental manufacturing. After breaking through technology bottlenecks, 3D printing will be more useful in the field of dental manufacturing in the future.

4.
Journal of Prevention and Treatment for Stomatological Diseases ; (12): 52-55, 2020.
Article in Chinese | WPRIM | ID: wpr-781209

ABSTRACT

@# Three dimensionally printed composite porous bone tissue engineering scaffolds have become a research focus. Composite polyvinyl alcohol (PVA) has good biocompatibilityand degradability, but it cannot be prepared indepen⁃dently because it cannot resist highmechanical resistance. This material shows many advantages, such as good biocom⁃patibility, degradability and mechanical properties, when compounded with other materials with good mechanical proper⁃ties and good biocompatibility. Therefore, 3D printed composite PVA scaffold material can optimize the performance of PVA scaffolds. This article reviews 3D printing bone scaffold technology, polyvinyl alcohol (PVA), and composite PVA scaffolds for in vivo and in vitro bone formation.

5.
The Journal of Korean Academy of Prosthodontics ; : 350-355, 2019.
Article in Korean | WPRIM | ID: wpr-761458

ABSTRACT

For the success of complete denture, three essential requirements such as retention, stability and support are needed. Moreover, due to the absorption of residual ridge and scarring due to the surgery, when making a complete denture, which is difficult to form the mandibular lingual margins, various considerations such as the arrangement of the Non-anatomical dl non-anatomical teeth, the polished surface impression, the internally weighted metal framework and the use of the denture adhesive cream are necessary. In this case report, the patient has a severely resorbed edentulous ridge from severe periodontitis and has some soft tissue problems after the glossectomy due to tongue cancer. To obtain additional retention and stability, some trials such as polished surface impression taking, internally weighted metal insertion and minimal pressure impression were done for the better result. Moreover To make a metal framework that precisely shapes the desired three-dimensional shape and reduces the complicated process, minimal pressure impression method and direct metal laser sintering technique were used.


Subject(s)
Humans , Absorption , Adhesives , Cicatrix , Denture, Complete , Dentures , Glossectomy , Methods , Periodontitis , Tongue Neoplasms , Tooth
6.
Journal of Prevention and Treatment for Stomatological Diseases ; (12): 189-193, 2019.
Article in Chinese | WPRIM | ID: wpr-751005

ABSTRACT

@#How to obtain ideal regeneration of periodontal tissue remains a challenge in the clinical treatment of periodontitis. Three-dimensional printing technology is based on computer-aided design, which produces materials with specific 3D shapes by layer-by-layer superposition, and has been applied to periodontal tissue regeneration therapy, this method offers hope to achieve ideal periodontal regeneration. This article reviews the application of 3D printing technology in the field of periodontal tissue regeneration. The literature review results show that 3D printing technology can design three-dimensional structures using computer software in advance and produce materials with specific three-dimensional structures. 3D printing technology mainly includes selective laser sintering, selective laser melting, extrusion forming printing and 3D bioprinting. At present, the support materials prepared by 3D printing technology include ceramic materials, polymer materials and metals. Submaterials have been extensively studied given their high adjustability, and 3D-printed personalized titanium mesh has been applied in the clinic. Multiphase materials prepared by 3D-printing technology can regenerate periodontal tissue in animal experiments, but the effect is not good in patients with periodontitis. In addition, 3D printing of composite scaffolds for periodontal tissue regeneration need to be further studied.

7.
West China Journal of Stomatology ; (6): 532-538, 2018.
Article in Chinese | WPRIM | ID: wpr-772463

ABSTRACT

OBJECTIVE@#This work aims to analyze the mechanical properties and biocompatibility of porous titanium (Ti) implants fabricated by selective laser sintering (SLS) and investigate the promotion of osseointegration by porous titanium implant combined with chitosan (CS)/hydroxyapatite(HA) composite coating.@*METHODS@#Ti6Al4V specimens were prepared, and CS/HA composite coating was fabricated on the surface of a portion of the specimens. The mechanical properties of the samples were observed by scanning electron microscope. MC3T3-E1 cells were cultured in vitro, and their biological properties in vitro were analyzed using live and dead viability cell staining method, methyl thiazolyl tetrazolium (MTT) staining, and alkaline phosphatase (ALP) level detection. The thread implant specimens were implanted in the femoral condyle of rabbits, and biological performance was evaluated in vivo.@*RESULTS@#Quasi-elastic gradient of porous specimens decreased with increasing porosity, and the quasi-elastic gradient were close to cortical and cancellous bone when the porosities were 30% and 70%. The specimens showed good biocompatibility. Combined with CS/HA coating, the implants promoted the proliferation and differentiation of MC3T3-E1 cells and facilitated the entry of bone tissue into pores and good osteogenesis.@*CONCLUSIONS@#The porous titanium implant exhibited favorable mechanical properties and biocompatibility. Combined with CS/HA coating, the implant exhibited bone inducibility, which leads to stable osteogenesis.


Subject(s)
Animals , Rabbits , Durapatite , Lasers , Materials Testing , Microscopy, Electron, Scanning , Osseointegration , Porosity , Prostheses and Implants , Surface Properties , Titanium
8.
The Journal of Korean Academy of Prosthodontics ; : 173-178, 2018.
Article in English | WPRIM | ID: wpr-713963

ABSTRACT

The direct metal laser sintering (DMLS) technique would be promising for the full-arch implant-supported restorations due to reduced cost and manufacturing time without potential human errors and casting defects. The aims of this case report were to describe the successful outcome of an implant-supported fixed dental prosthesis in the edentulous maxilla by using the DMLS technology and computer-aided design and computer-aided manufacturing (CAD/CAM) monolithic zirconia crowns, and to describe its clinical implications. A healthy 51-year-old Korean woman visited Seoul National University Dental Hospital and she was in need of a rehabilitation of her entire maxilla due to severe tooth mobility. In this case, all maxillary teeth were extracted and an implant-supported fixed dental prosthesis was fabricated that involved a cobalt-chromium (Co-Cr) framework with the DMLS technique and CAD/CAM monolithic zirconia crowns. Six months after delivery, no distinct mechanical and biological complications were detected and the prosthesis exhibited satisfactory esthetics and function. In this case report, with the DMLS system, the three-dimensional printed prosthesis was created without additional manual tooling and thus, reliable accuracy and passive fit were obtained.


Subject(s)
Female , Humans , Middle Aged , Computer-Aided Design , Crowns , Dental Prosthesis , Esthetics , Maxilla , Prostheses and Implants , Rehabilitation , Seoul , Tooth , Tooth Mobility
9.
The Journal of Advanced Prosthodontics ; : 93-100, 2018.
Article in English | WPRIM | ID: wpr-742026

ABSTRACT

PURPOSE: The purpose of this study was to determine the changing frequency of a diamond bur after multiple usages on 3 different surfaces. MATERIALS AND METHODS: Human premolar teeth (N = 26), disc shaped direct metal laser sintered CoCr (N = 3) and zirconia specimens (N = 3) were used in this study. Groups named basically as Group T for teeth, Group M for CoCr, and Group Z for zirconia. Round tapered black-band diamond bur was used. The specimens were randomly divided into three groups and placed with a special assembly onto the surveyor. 1, 5, and 10 preparation protocols were performed to the first, second, and third sub-groups, respectively. The subgroups were named according to preparation numbers (1, 5, 10). The mentioned bur of each group was then used at another horizontal preparation on a new tooth sample. The same procedure was used for CoCr and zirconia disc specimens. All of the bur surfaces were evaluated using roughness analysis. Then, horizontal tooth preparation surfaces were examined under both stereomicroscope and SEM. The depth maps of tooth surfaces were also obtained from digital stereomicroscopic images. The results were statistically analyzed using One-Way ANOVA, and the Tukey HSD post-hoc tests (α=.05). RESULTS: All of the groups were significantly different from the control group (P < .001). There was no significant difference between groups Z5 and Z10 (P=.928). Significant differences were found among groups T5, M5, and Z5 (P < .001). CONCLUSION: Diamond burs wear after multiple use and they should be changed after 5 teeth preparations at most. A diamond bur should not be used for teeth preparation after try-in procedures of metal or zirconia substructures.


Subject(s)
Humans , Bicuspid , Dental Instruments , Diamond , Tooth , Tooth Preparation
10.
The Journal of Advanced Prosthodontics ; : 25-31, 2018.
Article in English | WPRIM | ID: wpr-742013

ABSTRACT

PURPOSE: The aim of the present study was to record the metal-ceramic bond strength of a feldspathic dental porcelain and a Co-Cr alloy, using the Direct Metal Laser Sintering technique (DMLS) for the fabrication of metal substrates. MATERIALS AND METHODS: Ten metal substrates were fabricated with powder of a dental Co-Cr alloy using DMLS technique (test group) in dimensions according to ISO 9693. Another ten substrates were fabricated with a casing dental Co-Cr alloy using classic casting technique (control group) for comparison. Another three substrates were fabricated using each technique to record the Modulus of Elasticity (E) of the used alloys. All substrates were examined to record external and internal porosity. Feldspathic porcelain was applied on the substrates. Specimens were tested using the three-point bending test. The failure mode was determined using optical and scanning electron microscopy. The statistical analysis was performed using t-test. RESULTS: Substrates prepared using DMLS technique did not show internal porosity as compared to those produced using the casting technique. The E of control and test group was 222 ± 5.13 GPa and 227 ± 3 GPa, respectively. The bond strength was 51.87 ± 7.50 MPa for test group and 54.60 ± 6.20 MPa for control group. No statistically significant differences between the two groups were recorded. The mode of failure was mainly cohesive for all specimens. CONCLUSION: Specimens produced by the DMLS technique cover the lowest acceptable metal-ceramic bond strength of 25 MPa specified in ISO 9693 and present satisfactory bond strength for clinical use.


Subject(s)
Alloys , Dental Porcelain , Elastic Modulus , Microscopy, Electron, Scanning , Porosity
11.
Tissue Engineering and Regenerative Medicine ; (6): 187-200, 2017.
Article in English | WPRIM | ID: wpr-644058

ABSTRACT

Solid freeform techniques are revolutionising technology with great potential to fabricate highly organized biodegradable scaffolds for damaged tissues and organs. Scaffolds fabricated via Solid freeform (SFF) techniques have more pronounced effect in bone tissue engineering. SFF techniques produce various types of scaffolds from different biomaterials with specific pore size, geometries, orientation, interconnectivity and anatomical shapes. Scaffolds needs to be designed from such biomaterials which can attach directly to natural tissues and mimic its properties, so ideally mechanical properties of scaffolds should be same as that of regenerating tissues for best results. The scaffolds designed without optimized mechanical properties would lead to the reduced nutrition diffusion within tissue engineered constructs (TECs) causing tissue necrosis. These scaffolds are mainly processed from ceramics and polymers like calcium phosphate, polydioxane, €-polycaprolactone, polylactic and polyglycolic acids etc. While, hydrogel scaffolds provide bridge for encapsulated cells and tissues to integrate with natural ECM. Likewise, 2D images from radiography were not sufficient for the prediction of the brain structure, cranial nerves, vessel and architecture of base of the skull and bones, which became possible using the 3D prototyping technologies. Any misrepresentation can lead to fatal outcomes. Biomodelling from these techniques for spinal surgery and preoperative planning are making its way toward successful treatment of several spinal deformities and spinal tumor. In this review we explored laser based and printing SFF techniques following its methodologies, principles and most recent areas of application with its achievements and possible challenges faced during its applications.


Subject(s)
Biocompatible Materials , Bone and Bones , Brain , Calcium , Ceramics , Congenital Abnormalities , Cranial Nerves , Diffusion , Fatal Outcome , Hydrogels , Necrosis , Polyglycolic Acid , Polymers , Printing, Three-Dimensional , Radiography , Skull
12.
Ciênc. rural ; 47(8): e20160757, 2017. tab, graf
Article in English | LILACS | ID: biblio-839886

ABSTRACT

ABSTRACT: Long bone fractures are commonly in surgery routine and several bone imobilization techniques are currently available. Technological progress has enabled to use low cost materials in surgical procedures. Thus, the aim of this study was to evaluate the applicability of polyamide 12 rods, solid and hollow in swine femurs, comparing them through flexion strength. This study had as second aim to fix the locking errors, commom place in interlocking nails, once polyamide 12 allows perforation in any direction by orthopaedic screw. Six groups were used: G1 - eight whole swine femurs; G2 - eight whole swine femurs with drilled medullary canal; G3 - two solid polyamide 12 rods; G4 - two hollow polyamide 12 rods; G5 - eight osteotomized drilled swine femurs with a solid polyamide 12 rod implanted in the medullary canal and locked by four 316L stainless steel screws; and G6 - similar to G5 but using hollow rods instead of solid ones. No significant differences were observed for the modulus of rupture between solid and hollow rods, demonstrating that both rods had similar performances. These results led to the speculation that the addition of other polymers to the hollow rods could increase their strength and thus the bone-implant system. Furthermore, the comparison between G1, G5 and G6 could be analyzed using the finite element method in future. New polymeric materials may be developed based on the data from this study, strengthening the bone-implant system and making possible screws to be placed in any direction, nullifying the detrimental forces on the fracture site.


RESUMO: Fraturas em ossos longos são comumente encontradas na rotina cirúrgica e várias técnicas de imobilização óssea estão disponíveis. Com o avanço tecnológico, tornou-se viável utilizar materiais de baixo custo nos procedimentos, portanto esse estudo objetivou avaliar a aplicabilidade de hastes de poliamida 12, sólidas e vazadas, implantadas em fêmures suínos, comparando-as segundo as forças de flexão e aos erros de bloqueio, corriqueiros nesse implante, uma vez que a poliamida 12 permite sua perfuração em qualquer direção por meio de parafusos ortopédicos. Seis grupos foram usados: G1 - oito fêmures suínos íntegros; G2 - oito fêmures suínos, fresados intramedularmente; G3 - duas hastes maciças de poliamida 12; G4 - duas hastes vazadas de poliamida 12; G5 - oito fêmures suínos osteotomizados e fresados, com haste de poliamida 12 maciça implantada no canal medular e bloqueada com quatro parafusos de aço inoxidável 316L e G6 - diferente de G5 apenas por utilizar hastes vazadas. Não foram observadas diferenças significativas no módulo de ruptura entre hastes sólidas e vazadas, demonstrando que ambas apresentaram o mesmo desempenho. Estes resultados levaram à especulação de que adicionar outros polímeros às hastes vazadas aumentaria sua força e, portanto, do sistema osso-implante. Além disso, a comparação entre G1, G5 e G6 poderia no futuro ser analisada utilizando o método dos elementos finitos. Novos polímeros podem ser desenvolvidos baseando-se nos dados deste estudo, reforçando o sistema osso-implante e também possibilitando o uso de perfurações para o bloqueio no transoperatório em qualquer direção, anulando as forças deletérias atuantes no sítio de fratura.

13.
Journal of Practical Stomatology ; (6): 763-766, 2016.
Article in Chinese | WPRIM | ID: wpr-506251

ABSTRACT

Objective:To compare the fit of Co-Cr basal crowns fabricated by three kinds of technology. Methods:18 laser cured resin dies were divided into A, B and C groups(n=6) randomly. Co-Cr basal crowns of group A, B and C were made by traditional casting technology, CAD/CAM cutting metal technology and direct metal laser sintering technology( DMLS) respectively. The crowns were cemented to the corresponding dies and the basal crowns and dies were embedded in methyl acrylic. The thickness of the cement layer of the samples was measured under a stero microscope. Data were analyzed with SPSS13. 0 statistical software. Results:Marginal gap of group A, B and C was (66.08 ±3.90) μm, (29.21 ±3.31) μm and (24.96 ±2.99) μm respectively(P0. 05). Conclusion:DMLS technology may make the best marginal fit, CAD/CAM and DMLS technology may pro-duce better internal fit. The marginal fit and the internal fit of the crowns prepared by the 3 methods can meet the clinical requirements.

14.
Journal of Dental Rehabilitation and Applied Science ; : 246-254, 2016.
Article in Korean | WPRIM | ID: wpr-217990

ABSTRACT

Nowadays, 3 dimentional (3D) printing, especially Direct Metal Laser Sintering (DMLS) system is used in dentistry. DMLS system has recently been introduced for fabrication metal framework for metal ceramic crowns to overcome the disadvantages of the casting method and computer aided design/computer aided manufacturing (CAD/CAM) milling system. DMLS system uses a high-temperature laser beam to selectively heat a substructure metal powder based on the CAD data with the framework design. A thin layer of the beamed area becomes fused, and the metal framework is completed by laminating these thin layers. Utilizing DMLS system to fabricate fixed prostheses is expected to achieve free-from shaping without mold and limitations from cutting tools, fabricate prostheses with complex geometry, prevent distortion and fabrication defects that inherent to conventional fabrication methods. The purpose of this case report is to demonstrate various fixed prostheses such as long span fixed prostheses, post to achieve satisfactory results in functional and esthetic aspects.


Subject(s)
Ceramics , Crowns , Dentistry , Fungi , Hot Temperature , Methods , Printing, Three-Dimensional , Prostheses and Implants
15.
Journal of Practical Stomatology ; (6): 474-477, 2015.
Article in Chinese | WPRIM | ID: wpr-463009

ABSTRACT

Objective:To evaluate the surface free energy and Streptococcus mutans(S.mutans)adhesion on the surfaces of Co-Cr al-loy specimens fabricated by selective laser sintering(SLS)and casting method(SG and W280)respectively.Methods:The specimens of three groups were polished by SiC sandpaper.Surface morphology test,surface contact angle test and surface adhesion test of S.mu-tans were performed.Results:With the same surface roughness value,the surface contact angle of group SLS,W280 and SG was 66.200 ±3.112,74.212 ±3.206 and 67.238 ±2.047(P >0.05),the surface adhesion of S.mutans colone was 8.88 ±2.90,9.25 ± 2.05 and 8.50 ±1.85(P >0.05),respectively.Conclusion:The cobalt chromium alloy fabricated by SLS and casting method have similar surface performance.

16.
Journal of Korean Dental Science ; : 41-47, 2015.
Article in English | WPRIM | ID: wpr-109302

ABSTRACT

Even though a conventional metal ceramic restoration is widely in use, its laboratory procedure is still technique-sensitive, complex, and time-consuming. A ceramic-pressed-to-metal restoration (PTM) can be a reliable alternative. However, simplified laboratory procedure for a PTM is still necessary. The article is to propose a technique that reduces time and effort to fabricate a PTM with the aid of computer-aided design, computer-aided manufacturing and selective laser sintering technologies.


Subject(s)
Ceramics , Computer-Aided Design
17.
The Journal of Advanced Prosthodontics ; : 122-128, 2015.
Article in English | WPRIM | ID: wpr-144378

ABSTRACT

PURPOSE: To assess the marginal and internal gaps of the copings fabricated by computer-aided milling and direct metal laser sintering (DMLS) systems in comparison to casting method. MATERIALS AND METHODS: Ten metal copings were fabricated by casting, computer-aided milling, and DMLS. Seven mesiodistal and labiolingual positions were then measured, and each of these were divided into the categories; marginal gap (MG), cervical gap (CG), axial wall at internal gap (AG), and incisal edge at internal gap (IG). Evaluation was performed by a silicone replica technique. A digital microscope was used for measurement of silicone layer. Statistical analyses included one-way and repeated measure ANOVA to test the difference between the fabrication methods and categories of measured points (alpha=.05), respectively. RESULTS: The mean gap differed significantly with fabrication methods (P<.001). Casting produced the narrowest gap in each of the four measured positions, whereas CG, AG, and IG proved narrower in computer-aided milling than in DMLS. Thus, with the exception of MG, all positions exhibited a significant difference between computer-aided milling and DMLS (P<.05). CONCLUSION: Although the gap was found to vary with fabrication methods, the marginal and internal gaps of the copings fabricated by computer-aided milling and DMLS fell within the range of clinical acceptance (<120 microm). However, the statistically significant difference to conventional casting indicates that the gaps in computer-aided milling and DMLS fabricated restorations still need to be further reduced.


Subject(s)
Replica Techniques , Silicones
18.
The Journal of Advanced Prosthodontics ; : 122-128, 2015.
Article in English | WPRIM | ID: wpr-144371

ABSTRACT

PURPOSE: To assess the marginal and internal gaps of the copings fabricated by computer-aided milling and direct metal laser sintering (DMLS) systems in comparison to casting method. MATERIALS AND METHODS: Ten metal copings were fabricated by casting, computer-aided milling, and DMLS. Seven mesiodistal and labiolingual positions were then measured, and each of these were divided into the categories; marginal gap (MG), cervical gap (CG), axial wall at internal gap (AG), and incisal edge at internal gap (IG). Evaluation was performed by a silicone replica technique. A digital microscope was used for measurement of silicone layer. Statistical analyses included one-way and repeated measure ANOVA to test the difference between the fabrication methods and categories of measured points (alpha=.05), respectively. RESULTS: The mean gap differed significantly with fabrication methods (P<.001). Casting produced the narrowest gap in each of the four measured positions, whereas CG, AG, and IG proved narrower in computer-aided milling than in DMLS. Thus, with the exception of MG, all positions exhibited a significant difference between computer-aided milling and DMLS (P<.05). CONCLUSION: Although the gap was found to vary with fabrication methods, the marginal and internal gaps of the copings fabricated by computer-aided milling and DMLS fell within the range of clinical acceptance (<120 microm). However, the statistically significant difference to conventional casting indicates that the gaps in computer-aided milling and DMLS fabricated restorations still need to be further reduced.


Subject(s)
Replica Techniques , Silicones
19.
The Journal of Advanced Prosthodontics ; : 312-316, 2015.
Article in English | WPRIM | ID: wpr-44183

ABSTRACT

PURPOSE: This study aimed to present the clinical applicability of restorations fabricated by a new method, by comparing the bond strength of between ceramic powder with different coefficient of thermal expansion and alloys fabricated by Selective laser sintering (SLS). MATERIALS AND METHODS: Fifty Co-Cr alloy specimens (25.0 x 3.0 x 0.5 mm) were prepared by SLS and fired with the ceramic (8.0 x 3.0 x 0.5 mm) (ISO 9693:1999). For comparison, ceramics with different coefficient of thermal expansion were used. The bond strength was measured by three-point bending testing and surfaces were observed with FE-SEM. Results were analyzed with a one-way ANOVA (alpha=.05). RESULTS: The mean values of Duceram Kiss (61.18 +/- 6.86 MPa), Vita VM13 (60.30 +/- 7.14 MPa), Ceramco 3 (58.87 +/- 5.33 MPa), Noritake EX-3 (55.86 +/- 7.53 MPa), and Vintage MP (55.15 +/- 7.53 MPa) were found. No significant difference was observed between the bond strengths of the various metal-ceramics. The surfaces of the specimens possessed minute gaps between the additive manufactured layers. CONCLUSION: All the five powders have bond strengths higher than the required 25 MPa minimum (ISO 9693); therefore, various powders can be applied to metal structures fabricated by SLS.


Subject(s)
Alloys , Ceramics , Fires , Powders
20.
The Journal of Advanced Prosthodontics ; : 266-271, 2014.
Article in English | WPRIM | ID: wpr-86721

ABSTRACT

PURPOSE: The purpose of this study was to compare the fracture strength of the metal and the bond strength in metal-ceramic restorations produced by selective laser sintering (SLS) and by conventional casting (CAST). MATERIALS AND METHODS: Non-precious alloy (StarLoy C, DeguDent, Hanau, Germany) was used in CAST group and metal powder (SP2, EOS GmbH, Munich, Germany) in SLS group. Metal specimens in the form of sheets (25.0 x 3.0 x 0.5 mm) were produced in accordance with ISO 9693:1999 standards (n=30). To measure the bond strength, ceramic was fired on a metal specimen and then three-point bending test was performed. In addition, the metal fracture strength was measured by continuing the application of the load. The values were statistically analyzed by performing independent t-tests (alpha=0.05). RESULTS: The mean bond strength of the SLS group (50.60 MPa) was higher than that of the CAST group (46.29 MPa), but there was no statistically significant difference. The metal fracture strength of the SLS group (1087.2 MPa) was lower than that of the CAST group (2399.1 MPa), and this difference was statistically significant. CONCLUSION: In conclusion the balling phenomenon and the gap formation of the SLS process may increase the metal-ceramic bond strength.


Subject(s)
Alloys , Ceramics , Fires
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