1
|
Singh M, Yadav BK, Phukela SS, Ritwal P, Nagpal A, Saluja P. Evaluation and comparison of vertical marginal fit of three different types of multiunit screw-retained framework fabricated for an implant-supported prosthesis - An in vitro study. J Indian Prosthodont Soc 2022; 22:240-248. [PMID: 36511053 PMCID: PMC9416961 DOI: 10.4103/jips.jips_28_22] [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: 12/31/2022] Open
Abstract
Aim The present study aimed to evaluate on a comparative basis the vertical marginal fit between conventionally casted, direct metal laser sintered (DMLS), and milled computer-aided design/computer-aided manufacturing (CAD-CAM) one-piece metal framework supported by five implants using one-screw test and screw resistance test. Settings and Design This is an in vitro study. Materials and Methods Five implants were placed parallel to one other in a Styrofoam master model. A total of 30 implant-supported screw-retained superstructures were manufactured using three techniques, i.e., conventionally casted, milled, and sintered. To evaluate the vertical marginal discrepancy, screw resistance test, and one-screw test were used, and measurements were made using a stereomicroscope. Statistical Analysis Used The data was analysed using two statistical tests, i.e., ANOVA and the post hoc Bonferroni test. Results On evaluating the frameworks using one-screw test, the mean vertical misfit value at the terminal implant for the control group was 292.58 ± 15.46μm, for conventionally casted framework 398.41 ± 21.13 μm, for DMLS 343.44 ± 24.73 μm, and for CAD-CAM was 304.03 ± 14.23 μm, whereas the average misfit values at four implants on applying screw resistance test were 1268.65 ± 84.24 (control), 1774.88 ± 67.70 (casted), 1508.02 ± 62.19 (DMLS), and 1367.29 ± 81.87 (CAD-CAM). The average misfit values on two implants using screw resistance test were 635.02 ± 57.33 for the control group; for conventionally casted, it was 879.75 ± 35.93; for (DMLS) framework, it was 761.51 ± 32.85; and for milled CAD-CAM framework, it was 687.07 ± 42.17 μm. Conclusion The mean vertical marginal discrepancy, when compared with control, was least in milled CAD-CAM frameworks, followed by sintered DMLS and conventionally casted frameworks. Hence, according to the present study, CAD/CAM technique is recommended to achieve maximum marginal fit in full mouth screw-retained implant-supported FDPs.
Collapse
Affiliation(s)
- Mahima Singh
- Department of Prosthodontics, Faculty of Dental Sciences, SGT University, Gurgaon, Haryana, India
| | - Bhupender Kumar Yadav
- Department of Prosthodontics, Faculty of Dental Sciences, SGT University, Gurgaon, Haryana, India,Address for correspondence: Dr. Bhupender Kumar Yadav, House No. 1358, Sector 10 A, Gurgaon - 122 001, Haryana, India. E-mail:
| | - Sumit Singh Phukela
- Department of Prosthodontics, Faculty of Dental Sciences, SGT University, Gurgaon, Haryana, India
| | - Pankaj Ritwal
- Department of Prosthodontics, Faculty of Dental Sciences, SGT University, Gurgaon, Haryana, India
| | - Abhishek Nagpal
- Department of Prosthodontics, Faculty of Dental Sciences, SGT University, Gurgaon, Haryana, India
| | - Pulin Saluja
- Department of Oral Pathology, Faculty of Dental Sciences, SGT University, Gurgaon, Haryana, India
| |
Collapse
|
2
|
Kokolis J, Chakmakchi M, Theocharopoulos A, Prombonas A, Zinelis S. Mechanical and interfacial characterization of laser welded Co-Cr alloy with different joint configurations. J Adv Prosthodont 2015; 7:39-46. [PMID: 25722836 PMCID: PMC4341185 DOI: 10.4047/jap.2015.7.1.39] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Revised: 09/16/2014] [Accepted: 09/18/2014] [Indexed: 11/18/2022] Open
Abstract
PURPOSE The mechanical and interfacial characterization of laser welded Co-Cr alloy with two different joint designs. MATERIALS AND METHODS Dumbbell cast specimens (n=30) were divided into 3 groups (R, I, K, n=10). Group R consisted of intact specimens, group I of specimens sectioned with a straight cut, and group K of specimens with a 45° bevel made at the one welding edge. The microstructure and the elemental distributions of alloy and welding regions were examined by an SEM/EDX analysis and then specimens were loaded in tension up to fracture. The tensile strength (TS) and elongation (ε) were determined and statistically compared among groups employing 1-way ANOVA, SNK multiple comparison test (α=.05) and Weibull analysis where Weibull modulus m and characteristic strength σο were identified. Fractured surfaces were imaged by a SEM. RESULTS SEM/EDX analysis showed that cast alloy consists of two phases with differences in mean atomic number contrast, while no mean atomic number was identified for welded regions. EDX analysis revealed an increased Cr and Mo content at the alloy-joint interface. All mechanical properties of group I (TS, ε, m and σο) were found inferior to R while group K showed intermediated values without significant differences to R and I, apart from elongation with group R. The fractured surfaces of all groups showed extensive dendritic pattern although with a finer structure in the case of welded groups. CONCLUSION The K shape joint configuration should be preferred over the I, as it demonstrates improved mechanical strength and survival probability.
Collapse
Affiliation(s)
- John Kokolis
- Department of Biomaterials, School of Dentistry, National and Kapodistrian, University of Athens, Greece. ; Department of Dental Technology, Technological Educational Institution of Athens, Greece
| | | | | | - Anthony Prombonas
- Department of Dental Technology, Technological Educational Institution of Athens, Greece
| | - Spiros Zinelis
- Department of Biomaterials, School of Dentistry, National and Kapodistrian, University of Athens, Greece
| |
Collapse
|
3
|
Al Jabbari YS, Koutsoukis T, Barmpagadaki X, El-Danaf EA, Fournelle RA, Zinelis S. Effect of Nd:YAG laser parameters on the penetration depth of a representative Ni-Cr dental casting alloy. Lasers Med Sci 2013; 30:909-14. [PMID: 24326743 DOI: 10.1007/s10103-013-1502-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Accepted: 11/25/2013] [Indexed: 11/26/2022]
Abstract
The effects of voltage and laser beam (spot) diameter on the penetration depth during laser beam welding in a representative nickel-chromium (Ni-Cr) dental alloy were the subject of this study. The cast alloy specimens were butted against each other and laser welded at their interface using various voltages (160-390 V) and spot diameters (0.2-1.8 mm) and a constant pulse duration of 10 ms. After welding, the laser beam penetration depths in the alloy were measured. The results were plotted and were statistically analyzed with a two-way ANOVA, employing voltage and spot diameter as the discriminating variables and using Holm-Sidak post hoc method (a = 0.05). The maximum penetration depth was 4.7 mm. The penetration depth increased as the spot diameter decreased at a fixed voltage and increased as the voltage increased at a fixed spot diameter. Varying the parameters of voltage and laser spot diameter significantly affected the depth of penetration of the dental cast Ni-Cr alloy. The penetration depth of laser-welded Ni-Cr dental alloys can be accurately adjusted based on the aforementioned results, leading to successfully joined/repaired dental restorations, saving manufacturing time, reducing final cost, and enhancing the longevity of dental prostheses.
Collapse
Affiliation(s)
- Youssef S Al Jabbari
- Dental Biomaterials Research and Development Chair, College of Dentistry, King Saud University, P.O. Box 60169, Riyadh, 11545, Saudi Arabia,
| | | | | | | | | | | |
Collapse
|
4
|
Effects of conventional welding and laser welding on the tensile strength, ultimate tensile strength and surface characteristics of two cobalt-chromium alloys: a comparative study. J Indian Prosthodont Soc 2013; 12:87-93. [PMID: 23858281 DOI: 10.1007/s13191-012-0118-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2011] [Accepted: 04/05/2012] [Indexed: 10/28/2022] Open
Abstract
The purpose of this study was to evaluate the efficacy of laser welding and conventional welding on the tensile strength and ultimate tensile strength of the cobalt-chromium alloy. Samples were prepared with two commercially available cobalt-chromium alloys (Wironium plus and Diadur alloy). The samples were sectioned and the broken fragments were joined using Conventional and Laser welding techniques. The welded joints were subjected to tensile and ultimate tensile strength testing; and scanning electron microscope to evaluate the surface characteristics at the welded site. Both on laser welding as well as on conventional welding technique, Diadur alloy samples showed lesser values when tested for tensile and ultimate tensile strength when compared to Wironium alloy samples. Under the scanning electron microscope, the laser welded joints show uniform welding and continuous molt pool all over the surface with less porosity than the conventionally welded joints. Laser welding is an advantageous method of connecting or repairing cast metal prosthetic frameworks.
Collapse
|
5
|
Barbi FCL, Camarini ET, Silva RS, Endo EH, Pereira JR. Comparative analysis of different joining techniques to improve the passive fit of cobalt-chromium superstructures. J Prosthet Dent 2013; 108:377-85. [PMID: 23217470 DOI: 10.1016/s0022-3913(12)60196-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
STATEMENT OF PROBLEM The influence of different joining techniques on passive fit at the interface structure/abutment of cobalt-chromium (Co-Cr) superstructures has not yet been clearly established. PURPOSE The purpose of this study was to compare 3 different techniques of joining Co-Cr superstructures by measuring the resulting marginal misfit in a simulated prosthetic assembly. MATERIAL AND METHODS A specially designed metal model was used for casting, sectioning, joining, and measuring marginal misfit. Forty-five cast bar-type superstructures were fabricated in a Co-Cr alloy and randomly assigned by drawing lots to 3 groups (n=15) according to the joining method used: conventional gas-torch brazing (G-TB), laser welding (LW), and tungsten inert gas welding (TIG). Joined specimens were assembled onto abutment analogs in the metal model with the 1-screw method. The resulting marginal misfit was measured with scanning electron microscopy (SEM) at 3 different points: distal (D), central (C), and mesial (M) along the buccal aspect of both abutments: A (tightened) and B (without screw). The Levene test was used to evaluate variance homogeneity and then the Welsch ANOVA for heteroscedastic data (α=.05). RESULTS Significant differences were found on abutment A between groups G-TB and LW (P=.013) measured mesially and between groups G-TB and TIG (P=.037) measured centrally. On abutment B, significant differences were found between groups G-TB and LW (P<.001) and groups LW and TIG (P<.001) measured mesially; groups G-TB and TIG (P=.007) measured distally; and groups G-TB and TIG (P=.001) and LW and TIG (P=.007) measured centrally. CONCLUSIONS The method used for joining Co-Cr prosthetic structures had an influence on the level of resulting passive fit. Structures joined by the tungsten inert gas method produced better mean results than did the brazing or laser method.
Collapse
Affiliation(s)
- Francisco C L Barbi
- Maringá, Paraná, Brazil, School of Dentistry, State University of Maringá, Maringá, Paraná, Brazil.
| | | | | | | | | |
Collapse
|
6
|
TAKAYAMA Y, NOMOTO R, NAKAJIMA H, OHKUBO C. Effects of argon gas flow rate on laser-welding. Dent Mater J 2012; 31:316-26. [PMID: 22447067 DOI: 10.4012/dmj.2011-158] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Yasuko TAKAYAMA
- Department of Removable Prosthodontics, Tsurumi University School of Dental Medicine
| | - Rie NOMOTO
- Department of Dental Engineering, Tsurumi University School of Dental Medicine
| | | | - Chikahiro OHKUBO
- Department of Removable Prosthodontics, Tsurumi University School of Dental Medicine
| |
Collapse
|
7
|
Kikuchi H, Kurotani T, Kaketani M, Hiraguchi H, Hirose H, Yoneyama T. Effect of laser irradiation conditions on the laser welding strength of cobalt-chromium and gold alloys. J Oral Sci 2011; 53:301-5. [PMID: 21959656 DOI: 10.2334/josnusd.53.301] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Abstract
Using tensile tests, this study investigated differences in the welding strength of casts of cobalt-chromium and gold alloys resulting from changes in the voltage and pulse duration in order to clarify the optimum conditions of laser irradiation for achieving favorable welding strength. Laser irradiation was performed at voltages of 150 V and 170 V with pulse durations of 4, 8, and 12 ms. For cobalt-chromium and gold alloys, it was found that a good welding strength could be achieved using a voltage of 170 V, a pulse duration of 8 ms, and a spot diameter of 0.5 mm. However, when the power density was set higher than this, defects tended to occur, suggesting the need for care when establishing welding conditions.
Collapse
Affiliation(s)
- Hisaji Kikuchi
- Department of Dental Materials, Nihon University School of Dentistry, Tokyo, Japan.
| | | | | | | | | | | |
Collapse
|
8
|
Yilmaz A, Akyil MŞ, Hologlu B. The Effect of Metal Primer Application and Nd:YAG Laser Irradiation on the Shear-Bond Strength Between Polymethyl Methacrylate and Cobalt-Chromium Alloy. Photomed Laser Surg 2011; 29:39-45. [DOI: 10.1089/pho.2009.2721] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Asude Yilmaz
- Department of Prosthodontics, Faculty of Dentistry, Atatürk University, Erzurum, Turkey
| | - Musa Şamil Akyil
- Department of Prosthodontics, Faculty of Dentistry, Atatürk University, Erzurum, Turkey
| | - Bilal Hologlu
- Department of Prosthodontics, Faculty of Dentistry, Atatürk University, Erzurum, Turkey
| |
Collapse
|
9
|
Aladağ A, Çömlekoğlu ME, Dündar M, Güngör MA, Artunç C. Effects of soldering and laser welding on bond strength of ceramic to metal. J Prosthet Dent 2011; 105:28-34. [DOI: 10.1016/s0022-3913(10)60187-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
10
|
HJALMARSSON L, SMEDBERG JI, WENNERBERG A. Material degradation in implant-retained cobalt-chrome and titanium frameworks. J Oral Rehabil 2010; 38:61-71. [DOI: 10.1111/j.1365-2842.2010.02127.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
11
|
Bertrand C, Poulon-Quintin A. Proposals for optimization of laser welding in prosthetic dentistry. J Prosthodont 2009; 19:69-76. [PMID: 19780906 DOI: 10.1111/j.1532-849x.2009.00523.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
This paper points out each key parameter involved in laser welding and discusses the parameters' effects on weld microstructure and defects detected inside the weld. Solutions are proposed to adjust the parameters to provide an optimal dental assembly. Metallurgical effects as well as defects are briefly discussed. A welding procedure adapted to different compositions of dental alloys is proposed.
Collapse
Affiliation(s)
- Caroline Bertrand
- Department of Prosthodontics, TELEO, University of Nice Sophia-Antipolis, Nice, France.
| | | |
Collapse
|
12
|
|
13
|
Ma PS, Brudvik JS. Managing the maxillary partially edentulous patient with extensive anterior tooth loss and advanced periodontal disease using a removable partial denture: A clinical report. J Prosthet Dent 2008; 100:259-63. [PMID: 18922254 DOI: 10.1016/s0022-3913(08)60203-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- Polly S Ma
- Department of Restorative Dentistry, Division of Prosthodontics, University of Washington, Seattle, WA 98195-7452, USA.
| | | |
Collapse
|
14
|
Lee SY, Lin CT, Wang MH, Tseng H, Huang HM, Dong DR, Pan LC, Shih YH. Effect of temperature and flux concentration on soldering of base metal. J Oral Rehabil 2008. [DOI: 10.1111/j.1365-2842.2000.00614.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
|
15
|
Srimaneepong V, Yoneyama T, Kobayashi E, Doi H, Hanawa T. Comparative study on torsional strength, ductility and fracture characteristics of laser-welded α+β Ti–6Al–7Nb alloy, CP Titanium and Co–Cr alloy dental castings. Dent Mater 2008; 24:839-45. [DOI: 10.1016/j.dental.2007.10.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2007] [Revised: 09/24/2007] [Accepted: 10/09/2007] [Indexed: 11/17/2022]
|
16
|
Zupancic R, Legat A, Funduk N. Tensile strength and corrosion resistance of brazed and laser-welded cobalt-chromium alloy joints. J Prosthet Dent 2006; 96:273-82. [PMID: 17052472 DOI: 10.1016/j.prosdent.2006.08.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
STATEMENT OF PROBLEM The longevity of prosthodontic restorations is often limited due to the mechanical or corrosive failure occurring at the sites where segments of a metal framework are joined together. PURPOSE The purpose of this study was to determine which joining method offers the best properties to cobalt-chromium alloy frameworks. Brazed and 2 types of laser-welded joints were compared for their mechanical and corrosion characteristics. MATERIAL AND METHODS Sixty-eight cylindrical cobalt-chromium dental alloy specimens, 35 mm long and 2 mm in diameter, were cast. Sixteen specimens were selected for electrochemical measurements in an artificial saliva solution and divided into 4 groups (n=4). In the intact group, the specimens were left as cast. The specimens of the remaining 3 groups were sectioned at the center, perpendicular to the long-axis, and were subsequently rejoined by brazing (brazing group) or laser welding using an X- or I-shaped joint design (X laser and I laser groups, respectively). Another 16 specimens were selected for electrochemical measurements in a more acidic artificial saliva solution. These specimens were also divided into 4 groups (n=4) as described above. Electrochemical impedance spectroscopy and potentiodynamic polarization were used to assess corrosion potentials, breakdown potentials, corrosion current densities, total impedances at lowest frequency, and polarization charge-transfer resistances. The remaining 36 specimens were used for tensile testing. They were divided into 3 groups in which specimen pairs (n=6) were joined by brazing or laser welding to form 70-mm-long cylindrical rods. The tensile strength (MPa) was measured using a universal testing machine. Differences between groups were analyzed using 1-way analysis of variance (alpha=.05). The fracture surfaces and corrosion defects were examined with a scanning electron microscope. RESULTS The average tensile strength of brazed joints was 792 MPa and was significantly greater (P<.05) than the tensile strength of both types of laser-welded joints (404 MPa and 405 MPa). When laser welding was used, successful joining was limited to the peripheral aspects of the weld. The welding technique did not significantly affect the joint tensile strength. Electrochemical measurements indicated that the corrosion resistance of the laser-welded joints was better than of the brazed ones, primarily due to differences in passivation ability. CONCLUSION Laser welding provides excellent corrosion resistance to cobalt-chromium alloy joints, but strength is limited due to the shallow weld penetration. Brazed joints are less resistant to corrosion but have higher tensile strength than laser welds.
Collapse
Affiliation(s)
- Rok Zupancic
- Department of Prosthodontics, University of Ljubljana, Faculty of Medicine, Division of Dental Medicine, Slovenia.
| | | | | |
Collapse
|
17
|
Hassan L, Juszczyk AS, Clark RKF. Immediate replacement removable partial dentures with cobalt-chromium frameworks: rationale, technology and a case report. J Oral Rehabil 2005; 32:772-5. [PMID: 16159357 DOI: 10.1111/j.1365-2842.2005.01494.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The advantages of removable partial dentures with cobalt-chromium frameworks over those made entirely of acrylic resin, in oral health and hygiene, are well documented. However, in cases where teeth are to be extracted for fitting the removable partial denture, a difficulty arises because of the need to test the fit of the removable partial denture framework. The advent of two modern technologies-- laser welding and metal bonding agents -- make it possible to test the fit of the major part of the framework prior to adding additional metal components to support artificial teeth. A case is described in which the four lower incisors were extracted. The main part of the framework was constructed and its fit tested. A second casting was laser-welded to the lingual plate of the first casting to support the artificial incisor teeth. This technique avoids the need to make an acrylic resin temporary denture but incurs the cost of the additional technical work and so the advantages may be considered to be economically neutral.
Collapse
Affiliation(s)
- L Hassan
- GKT Dental Institute, King's College, London, UK.
| | | | | |
Collapse
|
18
|
Shehab AH, Pappas M, Burns DR, Douglas H, Moon PC. Comparative tensile strengths of preceramic and postceramic solder connectors using high-palladium alloy. J Prosthet Dent 2005; 93:148-52. [PMID: 15674225 DOI: 10.1016/j.prosdent.2004.11.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
STATEMENT OF PROBLEM It is not known whether different high-palladium alloys of similar composition possess comparable tensile strength properties associated with connector soldering. PURPOSE The purpose of this study was to evaluate the tensile strength properties of 2 high-palladium alloys on soldered connectors under simulated pre-ceramic and post-ceramic soldering conditions. MATERIAL AND METHODS Eighty cylindrical castings were fabricated (Rx Naturelle Plus alloy and Option alloy). The 40 castings for each alloy were subdivided into 2 groups of 20 each. In the first group, castings for each alloy were randomly paired and soldered with presolder (SMG2) to produce 10 preceramic test connector specimens for each alloy. In the second group, castings were similarly paired and soldered with postsolder (490 fine) to produce 10 postceramic test connector specimens for each alloy. Each soldered connector was subjected to tensile force until failure in a universal testing machine. Statistical analysis using a Wilcoxon rank sums test was performed (alpha=.05) RESULTS No significant difference was found between the mean tensile failure stress for Rx Naturelle Plus preceramic solder (344.7 +/- 77.6 MPa) compared to Option preceramic solder (411.5 +/- 112.8 MPa) (P =.1202). However, the mean tensile failure stress for Rx Naturelle Plus postceramic solder (260.8 +/- 223.7 MPa) was significantly lower than the Option postceramic solder (312.6 +/- 120.8 MPa) (P =.0407). Not only did Rx Naturelle Plus postceramic solder connectors show evidence of lower strength, but also an increased variation among specimens. CONCLUSIONS Rx Naturelle Plus solder connectors provided better strength with the preceramic as opposed with the postceramic connectors. For postsolder connectors, Rx Naturelle Plus alloy had less acceptable strength and a wider variation, suggesting it is more technique sensitive than Option alloy connectors.
Collapse
Affiliation(s)
- Abdul-Hadi Shehab
- Virginia Commonwealth University School of Dentistry, Richmond, VA 23298-0566, USA
| | | | | | | | | |
Collapse
|
19
|
Baba N, Watanabe I, Liu J, Atsuta M. Mechanical strength of laser-welded cobalt-chromium alloy. J Biomed Mater Res B Appl Biomater 2004; 69:121-4. [PMID: 15116400 DOI: 10.1002/jbm.b.10082] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The purpose of this study was to investigate the effect of the output energy of laser welding and welding methods on the joint strength of cobalt-chromium (Co-Cr) alloy. Two types of cast Co-Cr plates were prepared, and transverse sections were made at the center of the plate. The cut surfaces were butted against one another, and the joints welded with a laser-welding machine at several levels of output energy with the use of two methods. The fracture force required to break specimens was determined by means of tensile testing. For the 0.5-mm-thick specimens, the force required to break the 0.5-mm laser-welded specimens at currents of 270 and 300 A was not statistically different (p > 0.05) from the results for the nonwelded control specimens. The force required to break the 1.0-mm specimens double-welded at a current of 270 A was the highest value among the 1.0-mm laser-welded specimens. The results suggested that laser welding under the appropriate conditions improved the joint strength of cobalt- chromium alloy.
Collapse
Affiliation(s)
- N Baba
- Department of Developmental and Reconstructive Medicine, Division of Fixed Prosthodontics and Oral Rehabilitation, Course of Medical and Dental Sciences, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | | | | | | |
Collapse
|
20
|
Goto Y, Brudvik JS. Custom precision attachment housings for removable partial dentures. J Prosthet Dent 2002. [DOI: 10.1067/mpr.2002.127603] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
|