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Ghadhanfari HA, Khajah HM, Monaco EA, Kim H. Effects of soldering methods on tensile strength of a gold-palladium metal ceramic alloy. J Prosthet Dent 2014; 112:994-1000. [PMID: 24840906 DOI: 10.1016/j.prosdent.2014.02.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Revised: 02/10/2014] [Accepted: 02/10/2014] [Indexed: 11/28/2022]
Abstract
STATEMENT OF PROBLEM The tensile strength obtained by conventional postceramic application soldering and laser postceramic welding may require more energy than microwave postceramic soldering, which could provide similar tensile strength values. PURPOSE The purpose of the study was to compare the tensile strength obtained by microwave postceramic soldering, conventional postceramic soldering, and laser postceramic welding. MATERIAL AND METHODS A gold-palladium metal ceramic alloy and gold-based solder were used in this study. Twenty-seven wax specimens were cast in gold-palladium noble metal and divided into 4 groups: laser welding with a specific postfiller noble metal, microwave soldering with a postceramic solder, conventional soldering with the same postceramic solder used in the microwave soldering group, and a nonsectioned control group. All the specimens were heat treated to simulate a normal porcelain sintering sequence. An Instron Universal Testing Machine was used to measure the tensile strength for the 4 groups. The means were analyzed statistically with 1-way ANOVA. The surface and fracture sites of the specimens were subjectively evaluated for fracture type and porosities by using a scanning electron microscope. RESULTS The mean (standard deviation) ultimate tensile strength values were as follows: nonsectioned control 818 ±30 MPa, microwave 516 ±34 MPa, conventional 454 ±37 MPa, and laser weld 191 ±39 MPa. A 1-way ANOVA showed a significant difference in ultimate tensile strength among the groups (F3,23=334.5; P<.001). Follow-up multiple comparisons showed a significant difference among all the groups. Microwave soldering resulted in a higher tensile strength for gold and palladium noble metals than either conventional soldering or laser welding. CONCLUSION Conventional soldering resulted in a higher tensile strength than laser welding. Under the experimental conditions described, either microwave or conventional postceramic soldering would appear to satisfy clinical requirements related to tensile strength.
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Affiliation(s)
| | - Hasan M Khajah
- Consultant, Fixed Prosthodontics, Al-Amiri Dental Center, Kuwait City, Kuwait.
| | - Edward A Monaco
- Assistant Professor and Director, Postgraduate Prosthodontics, Department of Restorative Dentistry, School of Dental Medicine, State University of New York at Buffalo, Buffalo, NY
| | - Hyeongil Kim
- Assistant Professor, Postgraduate Prosthodontics, Department of Restorative Dentistry School of Dental Medicine, State University of New York at Buffalo, Buffalo, NY
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Kim H, Prasad S, Dunford R, Monaco EA. Strength properties of preceramic brazed joints of a gold-palladium alloy with a microwave-assisted oven and gas/oxygen torch technique. J Prosthet Dent 2014; 112:606-12. [PMID: 24656408 DOI: 10.1016/j.prosdent.2014.02.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
STATEMENT OF PROBLEM The effect of microwave brazing on the strength properties of dental casting alloys is not yet known. PURPOSE The purpose of this study was to compare the strength properties of preceramic brazed joints obtained by using a microwave oven and a conventional torch flame for a high noble alloy (Au-Pd). MATERIAL AND METHODS A total of 18 tensile bars made of an Au-Pd ceramic alloy were fabricated. Six specimens were cut and joined with a high-fusing preceramic solder in a specially designed microwave oven, and 6 specimens were joined with a conventional natural gas/oxygen torch. The remaining 6 uncut specimens were tested as a control. All the specimens were subjected to testing with a universal testing machine. A 1-way ANOVA was performed for each strength property tested. RESULTS The tensile strength of the uncut group was the highest (745 ±19 MPa), followed by the microwave group (420 ±68 MPa) and the conventional torch group (348 ±103 MPa) (P<.001); however, no significant difference in tensile strength was found between the microwave group and gas torch group. The tensile strength of the microwave group exceeded ANSI/ADA Standard No. 88, Dental Brazing Alloys (a joint standard of the American National Standards Institute and the American Dental Association). CONCLUSIONS The microwave heating preceramic solder method demonstrated the excellent tensile strength of an Au-Pd alloy and may be an alternative way of joining alloys when a torch flame is contraindicated.
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Affiliation(s)
- Hyeongil Kim
- Associate Professor, Restorative Dentistry, University at Buffalo, State University of New York, Buffalo, NY.
| | - Soni Prasad
- Assistant Professor, General Dental Sciences, Marquette University, Milwaukee, Wis
| | - Robert Dunford
- Statistician, Department of Oral Sciences, University at Buffalo, State University of New York, Buffalo, NY
| | - Edward A Monaco
- Assistant Professor, Restorative Dentistry, University at Buffalo, State University of New York, Buffalo, NY
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Nikellis I, Levi A, Zinelis S. Effect of soldering on the metal-ceramic bond strength of an Ni-Cr base alloy. J Prosthet Dent 2005; 94:435-9. [PMID: 16275303 DOI: 10.1016/j.prosdent.2005.09.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
STATEMENT OF PROBLEM Although soldering is a common laboratory procedure, the use of soldering alloys may adversely affect metal-ceramic bond strength and potentially decrease the longevity of metal-ceramic restorations. PURPOSE The purpose of this study was to investigate the effect of soldering on metal-ceramic bond strength of a representative Ni-Cr base metal alloy. MATERIAL AND METHODS Twenty-eight rectangular (25 x 3 x 0.5 mm) Ni-based alloy (Wiron 99) specimens were equally divided into soldering (S) and reference (R) groups. Soldering group specimens were covered with a 0.1-mm layer of the appropriate solder (Wiron-Lot) and reduced by 0.1 mm on the opposite side. Five specimens of each group were used for the measurement of surface roughness parameter (R(z)) and hardness, and 3 were used for measurement of the modulus of elasticity. Six specimens of each group were covered with porcelain (Ceramco 3) and subjected to a 3-point bending test for evaluation of the metal-ceramic bond strength according to the ISO 9693 specification. The data from surface roughness, hardness, modulus of elasticity, and metal-ceramic bond strength were analyzed statistically, using independent t tests (alpha=.05). RESULTS Statistical analysis of the R(z) surface roughness parameter (S: 3.4 +/- 0.3 mum; R: 3.7 +/- 0.7 microm; P=.07) and bond strength (S: 46 +/- 3 MPa; R: 40 +/- 5 MPa; P=.057) failed to reveal any significant difference between the 2 groups. The specimens of the soldering group demonstrated significantly lower values both in hardness (S: 128 +/- 11 VHN; R: 217 +/- 4 VHN; P<.001) and in modulus of elasticity (S: 135 +/- 4 GPa; R: 183 +/- 6 GPa; P=.035) than the reference group. CONCLUSION Under the conditions of the present study, the addition of solder to the base metal alloy did not affect the metal-ceramic bond strength.
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Affiliation(s)
- Ioannis Nikellis
- Department of Prosthodontics, School of Dentistry, University of Athens, Greece
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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.
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Affiliation(s)
- Abdul-Hadi Shehab
- Virginia Commonwealth University School of Dentistry, Richmond, VA 23298-0566, USA
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Zervas PJ, Papazoglou E, Beck FM, Carr AB. Distortion of three-unit implant frameworks during casting, soldering, and simulated porcelain firings. J Prosthodont 1999; 8:171-9. [PMID: 10740499 DOI: 10.1111/j.1532-849x.1999.tb00032.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
PURPOSE The aim of this study was to assess distortion inherent in casting, soldering, and simulated porcelain firings of screw-retained, implant-supported three-unit fixed partial dentures (FPDs). MATERIALS AND METHODS Ten wax patterns were fabricated on a die-stone cast containing two implants, 20 mm apart from center to center. Five specimens were cast in a high-palladium alloy, exposed to simulated porcelain firings, sectioned, and then soldered with low-fusing solder. Five specimens were cast, sectioned, soldered with high-fusing solder, and then exposed to simulated porcelain firings. For each specimen, two horizontal and six vertical distances between appropriately scribed reference points were measured with a traveling microscope. Comparisons were made among the various measurements taken after wax-pattern fabrication, casting, high- and low-fusing soldering, and each porcelain firing. Data were analyzed using a repeated-measures factorial ANOVA (alpha = 0.05). RESULTS Significant difference was detected in the amount of horizontal distortion during casting (53 +/- 24 microns) and high-fusing soldering (-49 +/- 50 microns), as well as in the amount of horizontal distortion during high-fusing soldering (-49 +/- 50 microns) and low-fusing soldering (17 +/- 26 microns). However, no clinically significant difference was found in the amount of horizontal distortion during casting, low-fusing, and high-fusing soldering. The greatest amount of distortion during the simulated porcelain firings took place during the oxidizing cycle. CONCLUSIONS Soldering did not improve the casting misfit of a three-unit implant-retained FPD model. Metal-ceramic implant frameworks should be oxidized before intraoral fit evaluation.
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Affiliation(s)
- P J Zervas
- Ohio State University, College of Dentistry, Columbus 43210-1241, USA
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Chaves M, Vermilyea SG, Papazoglou E, Brantley WA. Effects of three soldering techniques on the strength of high-palladium alloy solder joints. J Prosthet Dent 1998; 79:677-84. [PMID: 9627897 DOI: 10.1016/s0022-3913(98)70075-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
STATEMENT OF PROBLEM Little information is available on the optimum technique for soldering high-palladium alloys, which have gained considerable popularity for prosthodontic applications. PURPOSE The objective of this study was to compare the flexural stress at the proportional limit of four noble dental alloy specimens soldered with torch, oven, and infrared-techniques. MATERIALS AND METHODS The high-palladium alloys studied were Legacy XT (Jelenko), Freedom Plus (Jelenko), and IS 85 (Williams/Ivoclar). A gold-palladium alloy, Olympia (Jelenko), served as the control. Thirty round bars, 18 x 3 mm, were cast from each alloy, cut in half, aligned, and joined using Olympia Pre solder (Jelenko) for the gas-oxygen torch and the infrared technique and Alboro LF solder (Jelenko) for the oven technique. Each soldered bar was subjected to three-point bending, and the maximum elastic stress or strength of the solder joint was calculated at the proportional limit. Data were analyzed by two-way ANOVA and the Ryan-Einot-Gabriel-Welsch (REGW) multiple range test at the 0.05 level of significance. RESULTS There was no significant difference between torch and oven-soldering, but both were significantly different from the infrared technique. ANOVA showed a significant difference between alloys, but this difference could not be detected with the REGW test. SEM examination of the fracture surfaces revealed grooves associated with the path of crack propagation. X-ray energy-dispersive spectroscopic analysis failed to detect copper in the solders, and there were no significant changes in the solder compositions after the melting procedures. CONCLUSIONS All three techniques can yield satisfactory solder joints in high-palladium alloys. These joints should be well-polished to achieve optimal strength.
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Affiliation(s)
- M Chaves
- College of Dentistry, Ohio State University, Columbus, USA
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Abstract
STATEMENT OF PROBLEM Little information is available about the mechanical properties of soldered gold alloys after they have undergone various heat treatments. PURPOSE This study investigated the influence of heat treating on the strength properties of soldered joints of two gold alloys (NC Type IV and Sofard), which can be age-hardened at intraoral temperature. MATERIAL AND METHODS Dumbbell-shaped specimens were cast with each gold alloy and were cut at the center of the connecting bar for soldering. The two halves of the casting were then soldered with two different gold-based solders (Maingold and Degulor). Three different heat treatments were performed on the soldered gold alloy assemblies: solution heat treatment (ST) at 700 degrees C for 5 minutes (treatment A); aging at 37 degrees C for 7 days after ST (treatment B); and aging at 250 degrees C (Sofard) or 400 degrees C (NC type IV) for 15 minutes after ST (treatment C). The tensile strength, elongation and microhardness were evaluated after each heat treatment. RESULTS The hardness values of Sofard significantly (p < 0.05) increased during aging at 37 degrees C (treatment B) and produced adequate strengths of the soldered joints, especially with the harder solder (645.7 MPa: Degulor [222 VHN] vs. 493.3 MPa: Maingold [165 VHN]). CONCLUSIONS The results of this study indicated the possibility of strengthening soldered joints in the oral environment, thus eliminating the necessity for any additional hardening heat treatment.
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Affiliation(s)
- I Watanabe
- Department of Biomaterials Science, Baylor College of Dentistry-Texas A&M University System, Dallas, USA
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Dominici JT, Sobczak KP, Mitchell RJ. A comparison of infrared- and torch-soldering of Au-Pd and Co-Cr metal-ceramic alloys using a high-fusing solder. J Prosthodont 1995; 4:101-10. [PMID: 8528438 DOI: 10.1111/j.1532-849x.1995.tb00324.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
PURPOSE The purpose of this study was to compare the bond strengths and fracture modes of soldered joints formed by infrared and gas-oxygen torch heating of a high-fusing, gold-based solder in two metal-ceramic alloys. MATERIALS AND METHODS Pairs of half-dumbbell-shaped specimens of either an Au-Pd or a Co-Cr alloy were positioned with a 0.25-mm gap and were joined using a high-fusing, gold-based solder by either gas-oxygen torch heating or infrared heating. The resulting specimens were subjected to a heat treatment that simulated ceramic firing. Each specimen was fractured in tension at a loading rate of 0.5 cm/min, and its bond strength was measured. The halves of the specimen were rejoined using the other heating method and were heat treated, and the specimen's bond strength was again measured. Fractured cross-sections were examined at a magnification of 40x to determine the following: the fracture mode (adhesive, cohesive, or mixed); the percentage of adhesive fracture; the presence or absence of voids, porosities, or flux inclusions; and the percentage of the cross-section that was discolored. RESULTS Three-factor analyses of variance showed that neither the heating method, the particular specimen tested, nor the order of testing significantly affected the bond strength (P < .05). For each alloy, significantly fewer infrared-heated joints than torch-heated joints contained voids, porosities, or flux inclusions visible at 40x (chi 2 test, P < .05). All fractures were either entirely cohesive in the solder or mixed cohesive and adhesive. When infrared heating was used, entirely cohesive fractures occurred more frequently in the Au-Pd alloy specimens than in the Co-Cr alloy specimens (chi 2 test, P < .05). The coefficients of variation of the bond strengths for the infrared-heated joints were smaller than those for the torch-heated joints. CONCLUSIONS Although the two heating methods produced solder joints that had strengths that were not significantly different, infrared-heated joints showed less scatter in bond strengths. It was suggested that, in the hands of most technicians, fewer infrared-heated joints would contain defects visible at a magnification of 40x. The presence of such defects may increase the probability of in vivo failure caused by cyclic stresses.
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Affiliation(s)
- J T Dominici
- Department of Oral Health Practice, University of Kentucky, College of Dentistry, Lexington 40536-0084, USA
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Cheng AC, Chai JY, Gilbert J, Jameson LM. Investigation of stiffness and microstructure of joints soldered with gas-oxygen torch and infrared methods. J Prosthet Dent 1994; 72:8-15. [PMID: 7916054 DOI: 10.1016/0022-3913(94)90208-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The stiffness of soldered connectors fabricated with the gas-oxygen torch technique was compared with those fabricated with the infrared technique. Untreated solder materials were used as controls. Untreated solder materials of gold-palladium, palladium-silver, and chromium-cobalt alloys exhibited significantly higher stiffness than the soldered specimens fabricated with either method. There was no significant difference between the gas-oxygen torch and the infrared groups of the gold-palladium and palladium-silver alloys. Photomicrographs revealed that the soldered specimens displayed porosities. For the chromium-cobalt alloy, the infrared group demonstrated significantly higher stiffness than the gas-oxygen torch group. Photomicrographs also disclosed that the chromium-cobalt alloy soldered with the gas-oxygen torch technique had a significant heat-affected zone.
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Affiliation(s)
- A C Cheng
- Northwestern University Dental School, Chicago, Ill
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11
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Abstract
Soldered connectors for two base metal ceramic alloys (nickel-chromium and cobalt-chromium) were compared by use of four different techniques: (1) infrared preceramic soldering, (2) gas and oxygen preceramic soldering, (3) porcelain furnace postsoldering under vacuum, and (4) porcelain furnace postsoldering without vacuum. A control group was established with solid cast specimens of each alloy. No statistically significant difference was noted between infrared and torch preceramic soldering techniques for either of the two alloys. However, the joints postsoldered under vacuum were significantly superior to postsoldered connectors without vacuum (p < 0.0001). No significant differences were observed among techniques 1, 2, and 3, although the three groups were substantially superior to technique 4 for both alloys (p = 0.05). The control group for both alloys was appreciably stronger than the soldered groups (p < 0.0001), and the nickel-chromium samples within the control group were significantly stronger than the Co-Cr samples.
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Cattaneo G, Wagnild G, Marshall G, Watanabe L. Comparison of tensile strength of solder joints by infrared and conventional torch technique. J Prosthet Dent 1992; 68:33-7. [PMID: 1357164 DOI: 10.1016/0022-3913(92)90280-n] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Fabrication of a fixed partial denture may require a soldering step. This study compared soldering by a conventional torch procedure with an infrared soldering technique. Comparisons were made for tensile strength, porosity, and time efficiency between the two methods. No significant difference was found in ultimate tensile strength between the two types of solder joints and the nonsoldered control samples. Random samples photographed with a scanning electron microscope revealed no difference in joint porosity between the two techniques. Torch soldering took consistently less time that infrared soldering.
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Affiliation(s)
- G Cattaneo
- Graduate Prosthodontics Program, University of California, School of Dentistry, San Francisco
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Abstract
This study determined the accuracy of fit of three-unit fixed partial dentures joined by an infrared soldering technique compared with one-piece fixed partial denture castings and individually cast crowns. Wax patterns of prepared Ivorine teeth, maxillary left central incisor and maxillary left canine, were injection molded; a plastic rod was used as a pontic. One group of patterns was cast as one-piece dentures; the other group was sectioned in the connector area, cast individually and then joined by infrared soldering. Castings were seated on their respective dies, embedded in epoxy resin, and sectioned. Gap distances between the casting and the die were measured at specified marginal sites with a profile projector. Results showed that the fit of infrared-soldered fixed partial dentures was significantly better than that of one-piece castings and was comparable with the fit of single crowns. The gap openings measured in all castings were within the range of clinical acceptability.
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Affiliation(s)
- G Byrne
- Department of Fixed Prosthodontics, Loyola University of Chicago, School of Dentistry, Ill
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Goldstein GR, Wesson A, Schweitzer K, Cutler B. Flexion characteristics of four-unit fixed partial denture frameworks using holographic interferometry. J Prosthet Dent 1992; 67:609-13. [PMID: 1356156 DOI: 10.1016/0022-3913(92)90156-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Flexion of a metal/ceramic fixed partial denture (FPD) framework under function can cause fracture of the porcelain or deterioration of the cement seal. This study evaluated the flexion under compressive load of a four-unit mandibular FPD replacing the second premolar and the first molar. Testing was accomplished with elapsed time holographic interferometry, using 39 porcelain fused-to-metal frameworks cast with a silver-palladium alloy. The results demonstrated that solder joints at the junction of the premolar and molar pontics flexed under a reduced compressive load and exhibited a higher failure rate than other connector designs.
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Affiliation(s)
- G R Goldstein
- Division of Restorative and Prosthodontic Sciences, Kriser Dental Center, Division of Restorative and Prosthodontic Sciences, New York University, N.Y
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Abstract
The influence of corrosion on the bond strength of different brazed joints commonly used in dentistry has been investigated by means of accelerated immersion tests in artificial saliva buffered at pH 2, and in Ringer's solution, both kept at 37 degrees C. Two Co-Cr base metal alloys were brazed with a gold and a non-precious alloy. After 60 days' immersion the tensile strength of the samples brazed with the gold alloy was dramatically reduced because of galvanic corrosion phenomena. The bond strength of the specimens brazed with the non-precious alloy was largely unaffected. Corrosion products rich in nickel were detected. The electrochemical characterization of the base metal alloys and brazing materials was performed by means of polarization curves in the two media investigated. High short circuit currents were only produced with the gold brazing materials.
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Affiliation(s)
- E Angelini
- Dipartimento di Scienza dei Materiali e Ingegneria Chimica, Politecnico di Torino, Italy
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16
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Fehling AW. Cast connectors as cores for ceramometal pontics on removable partial dentures and for splinting anterior crowns. J Prosthet Dent 1990; 63:167-71. [PMID: 2406425 DOI: 10.1016/0022-3913(90)90101-h] [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: 12/31/2022]
Abstract
A cast connector is a solderless union between two metal components, an alternative to soldering. Cast connectors depend upon mechanical retention for their strength and integrity and are mostly used in repairing or adding to prostheses cast in base metal alloys. Two techniques using cast connectors are described. One is for a removable partial denture that requires the replacement of an anterior tooth or teeth incorporating diastemas or unusual surface anatomy and color variations. Stock denture teeth may not adequately replicate such teeth. A solution to the problem is to extend a porcelain-compatible base metal cast connector from the removable partial denture framework onto the pontic site. A ceramometal pontic reproducing the unusual characteristics of the natural teeth may then be placed by vacuum-firing porcelain directly onto the framework. A second technique is described whereby multiple ceramometal anterior crowns may be splinted together by creating interproximal retentive zones in the frameworks, casting connectors into the retentive zones, and proceeding with porcelain application.
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Gustavsen F, Berge M, Hegdahl T. Flexural strength of a high-temperature soldered cobalt-chromium alloy. J Prosthet Dent 1989; 61:568-71. [PMID: 2568484 DOI: 10.1016/0022-3913(89)90277-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The flexural strength of a high-temperature soldered cobalt-chromium alloy was compared with that of the intact alloy. In one test group the specimens were soldered by Vitallium welding rods and in the other group Bego cobalt-chromium solder was used. The cylindrical portion of all specimens was mounted equally in an Instron testing machine. No statistically significant differences were found in flexural strength between the groups.
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Affiliation(s)
- F Gustavsen
- Department of Prosthodontics, University of Bergen, Faculty of Dentistry, Norway
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18
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Abstract
Modifications and repairs of removable partial dentures usually involve solder joints. It is important to know the combination of solder and alloy that will provide the strongest junction. The purpose of this work was to investigate the mechanical strengths of different solders commonly used in dental practice. Specimens of three removable partial denture alloys (Dentitan, Crutanium, Wisil) were soldered with various solders having different melting temperatures. The soldered specimens were subjected to tensile testing, and the fracture surfaces were examined by means of scanning electron microscopy. Most of the failures occurred within the soldered joint, which is the weakest portion of a removable partial denture. Excessive use of flux to achieve an adequate flow of solder produced defects in the solder joint. A relationship was found between joint strength and solder fusion temperature for Crutanium and Wisil--the higher the fusion temperature, the higher the joint strength.
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Wesson A, Goldstein GR, Schulman A. Flexion characteristics of fixed partial denture frameworks tested by using elapsed-time holographic interferometry. J Prosthet Dent 1988; 60:308-10. [PMID: 2902222 DOI: 10.1016/0022-3913(88)90274-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- A Wesson
- Department of Comprehensive Care and Applied Management, New York University David B. Kriser Dental Center, College of Dentistry, New York
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Abstract
This article deals mainly with the development of dental casting techniques and formulation of the different groups of alloys used in the fabrication of ceramo-metal restorations. It is recognized that in order for the quality of dental cast restorations to be improved, having alloys with the proper composition is not enough. Biocompatibility, good mechanical and physical properties, longevity of the restoration, compatibility with porcelain, and a simple manipulative technique are as important. Researchers have contributed to different aspects of dental castings and have made cast restorations what they are today. Unfortunately, much of the original basic research has been overlooked by present investigators, who have duplicated studies conducted in the past without realizing that the study had already been performed and the research had been published. The main reason for this is that abstracts of articles published prior to 1975 are not available through a library computer-search system. To obtain copies of articles published prior to 1975, one has to search the literature to know where they were published. This article provides references for much of the past work in this area. Also, dental libraries do not carry copies of U.S. patents. This places the majority of researchers located at dental schools at a disadvantage. They are not familiar with what the patents claim, what is taught, and why certain elements are added or eliminated from alloys and investment materials. This article also provides the numbers of many U.S. patents. By having the patent number, one can obtain the text of the patent from the U.S. Patent Office in Washington, DC. Since esthetics plays an important role in today's society, emphasis will be given only to alloys designed for fabrication of ceramo-metal restorations. Many ceramo-metal alloys are available today, and they are classified differently by different individuals. In this article, classification will be based on the major components of these alloys, as well as on a chronological introduction of one group leading to the development of the next group. Based on this, one can classify these alloys into six major groups. Chemical composition, properties, and the developers of these alloys, along with their U.S. patents, are given. Recently, two types of all-ceramic restorations have been introduced. The main advantage of the all-ceramic restoration is its superior esthetic quality compared with that of ceramo-metal restorations. Their main disadvantages are low strength and ductility. Their strength, however, is sufficient for single-unit restorations, but not for bridgework. The use of titanium for dental restorations has also been studied, and it has been found to be suitable. Future Studies - Future work should be devoted to the following: (1) the development of stronger and more ductile ceramic materials: (2) further study of the promising palladium alloys from the noble metal group and titanium alloys from the base metal group; (3) the development of easier and less-time-consuming techniques for the fabrication of dental appliances; (4) the development of a powder technique rather than a cast technique for future fabrication methods; and (5) the development of new laboratory equipment, e.g., a single sintering oven capable of sintering both ceramic and metallic particles, which would be accepted if the powder technique is developed.
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Fitzig S, Eli I. Repair of an overcontoured cemented crown. J Prosthet Dent 1987; 58:558-9. [PMID: 3316602 DOI: 10.1016/0022-3913(87)90384-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
A method for retracting gingival tissue to allow recontouring of crown surfaces and removal of overhanging margins has been presented.
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Affiliation(s)
- S Fitzig
- Section of Prosthetic Dentistry, Tel Aviv University, School of Dental Medicine, Israel
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Sobieralski JA, Brukl CE, Smith NK. Tensile strengths and microscopic analysis of nickel-chromium base metal postceramic solder joints. J Prosthet Dent 1987; 58:35-42. [PMID: 2886657 DOI: 10.1016/s0022-3913(87)80139-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Abstract
A total of 120 three-unit fixed partial dentures were made by using a latex mold to produce uniform wax patterns. Four groups were used to compare the tensile strength of connectors with interproximal solder, midpontic vertical solder, midpontic diagonal solder, and a control of one-piece castings. Three different metals were tested and the tensile load required to fracture the samples as well as the fracture sites were recorded. The following was found: Soldering the interproximal connector area produced the weakest solder joints, regardless of metal tested, at p less than .001. There was no significant difference in the fracture loads between midpontic vertical soldering and midpontic diagonal soldering with all three metals at p less than .01. There was no significant difference in fracture loads between midpontic soldering and unit casting with all three metals at p less than .01. The extreme variations in fracture loads when soldering nickel-chrome-beryllium confirms the technique sensitivity of presoldering this alloy.
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Lorenzana RE, Staffanou RS, Marker VA, Okabe T. Strength properties of soldered joints for a gold-palladium alloy and a palladium alloy. J Prosthet Dent 1987; 57:450-4. [PMID: 2883315 DOI: 10.1016/0022-3913(87)90013-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Strength of a soldered palladium alloy, PGC (Engelhard Corp.), and a soldered medium gold alloy, PGX (Engelhard Corp.), was examined. The results obtained were as follows: Highest strength was observed with postsoldered specimens of PGC alloy. Microstructural examination of postsoldered specimens revealed nearly pore-free solder joints with PGC and PGX alloys, and fracture appeared at the solder-alloy interface with PGC and PGX alloys. Microstructural examination of presoldered and presoldered/thermocycled specimens revealed that presoldered specimens of PGC and PGX alloys exhibited intrasolder fracture; PGX solder joints had considerably less porosity, which may explain the equivalent bond strengths of all the soldered specimens and the yield point of the controls; PGC solder joints exhibited large quantities of pores, which may explain the lower strength; pores observed in PGC alloy may be the result of the high fusing temperature of the solder; and these results indicate a need to develop a new presolder for PGC. The best result was obtained with postsoldered specimens of the PGC alloy. However, for PGX alloy, either postsolder or presolder techniques can be used.
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Moskowitz H, Janus CE, Beck DA. Tensile strength of an alternative soldered connector. J Prosthet Dent 1987; 57:301-6. [PMID: 2883314 DOI: 10.1016/0022-3913(87)90302-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Boudrias P, Nicholls JI. Tensile strength of postceramic solder joints with a palladium-silver alloy. J Prosthet Dent 1987; 57:165-71. [PMID: 2882022 DOI: 10.1016/0022-3913(87)90140-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Beck DA, Moon PC, Janus CE. A quantitative study of preporcelain soldered connector strength with palladium-based porcelain bonding alloys. J Prosthet Dent 1986; 56:301-6. [PMID: 2875180 DOI: 10.1016/0022-3913(86)90008-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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30
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Ziebert GJ, Hurtado A, Glapa C, Schiffleger BE. Accuracy of one-piece castings, preceramic and postceramic soldering. J Prosthet Dent 1986; 55:312-7. [PMID: 2870184 DOI: 10.1016/0022-3913(86)90110-1] [Citation(s) in RCA: 36] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
An investigation was conducted to evaluate the relative accuracy of one-piece castings of FPDs of three, four, and five units with those assembled by preceramic soldering and postceramic soldering. The preceramic soldered FPDs were subjected to six simulated porcelain firing cycles to assure a homogeneous sample. A total of 15 FPDs, five of each length, were evaluated for each test condition. A three-piece aluminum mold with stainless steel dies, which allowed for varying the length of the prosthesis, was used to fabricate the FPDs in 52% gold-palladium alloy. Marginal discrepancies of the castings on the dies were compared for the three test techniques. The mesiodistal length of the FPDs that were pre- and postsoldered were also measured at the occlusal and at the gingival margins and compared with the restorations before soldering.
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Fehling AW, Sansom BP, Meiser ET, Johnson PF. Cast connectors: an alternative to soldering base metal alloys. J Prosthet Dent 1986; 55:195-7. [PMID: 2870183 DOI: 10.1016/0022-3913(86)90341-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
A solderless technique has been described for correcting an unstable framework of a base metal fixed partial denture. This technique has been used without failure since 1981 for cast joints with porcelain-fused-to-metal fixed partial dentures.
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Abstract
Twenty half-dumbbell shaped rods were cast in a silverless gold-palladium alloy that contained a minimum of 42% fresh alloy and the rest once-melted alloy. Each pair of half-dumbbells was assembled and either presoldered or postsoldered using a vacuum-oven and a torch-soldering technique. There was no significant difference in the ultimate tensile strength values between the presoldered and postsoldered joints within the same technique group, but the torch-soldered joints for the same solder were significantly stronger (p less than .01). It was believed that slow heating and cooling has deleterious effects on the ultimate tensile strength joints (UTS) possibly because of the microstructural changes and the highly oxidizable content of the postsolder used. Another 15 samples cast using once, twice, and three-times remelted parent alloy were presoldered and postsoldered with the torch only. In each of these groups, specimens joined by presolder showed significantly higher strength than those joined by postsolder (p less than .02). Remelting the parent alloy affected the strength differences between the presoldered and postsoldered joints. It was assumed that on remelting, the nature of the parent alloy is changed because some original elements are volatilized and newly formed oxides dissolved into it. Because it contains copper, the postsolder is more affected by this contamination than presolder. The UTS of the parent alloy, as well as that of the presolder and postsolder, were also determined. As expected, the parent alloy possessed the highest strength and the postsolder, the lowest.
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Anusavice KJ, Okabe T, Galloway SE, Hoyt DJ, Morse PK. Flexure test evaluation of presoldered base metal alloys. J Prosthet Dent 1985; 54:507-17. [PMID: 2864437 DOI: 10.1016/0022-3913(85)90423-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Janus CE, Beck DA, Moon PC. Quantitative study of soldered connector tensile strength using low-gold content alloys. J Prosthet Dent 1985; 54:517-21. [PMID: 2864438 DOI: 10.1016/0022-3913(85)90424-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Abstract
Prewetting the surface of a base metal alloy with solder prior to low temperature soldering produced strong, predictable, oxide-free joints similar to precious metal joints. The positive results were obtained whether the prewet base metal was soldered to other prewet base metal or to precious metals. Soldered combinations of non-prewet base metal showed lower strength, less predictability, and more oxide formation than the prewet counterparts. The prewetting concept was described for use with fixed prosthodontics or removable partial dentures.
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Marshall AG, Goodkind RJ. An investigation of the tensile strength of nickel-chromium alloy dental solder joints. J Prosthet Dent 1984; 52:666-72. [PMID: 6149316 DOI: 10.1016/0022-3913(84)90139-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Abstract
The ceramometal pontic has the greatest potential as an esthetic replacement for missing teeth. Maximum esthetic and mechanical properties are obtainable only with post-ceramic soldering. A means of maintaining positional stability for the pontic is offered, as well as some helpful hints in the use of the technique in various clinical situations.
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Kriebel R, Moore BK, Goodacre CJ, Dykema RW. A comparison of the strength of base metal and gold solder joints. J Prosthet Dent 1984; 51:60-6. [PMID: 6142109 DOI: 10.1016/s0022-3913(84)80108-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The purpose of this study was to evaluate the procedures involved in forming high- and low-fusing solder joints between two different base metal alloys and to compare the strength of these joints with the strength of those formed between specimens made from a high-gold content alloy. The conclusions of this investigation can be summarized as follows. All but 11 of the 120 specimens failed through the solder joint, which confirms that the solder joint is usually the weakest part of a fixed partial denture. The high-fusing joints formed between the base metal alloys showed higher relative bending strength values than the high-fusing joints formed between the gold alloy specimens. The low-fusing joints formed between the base metal alloys showed higher relative bending strength values than the low-fusing joints formed between the gold alloy specimens, and the low-fusing base metal joints exhibited the highest strength values in this study. The low-fusing joints formed between gold alloy specimens consistently bent before fracturing. Solder joints fail both adhesively (separation of the solder from the parent metal) and cohesively (fracture through the solder, parent metal, or a combination of both). A correctly formed joint between gold components should show cohesive fracture, whereas adhesive fractures are apparently acceptable with base metal alloys since the low-fusing base metal joints failed in this manner but still exhibited high strength values. Voids of different sizes and locations were observed in most of the solder joints, and within each group tested there was usually less strength exhibited by the joints with larger areas of porosity.
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Apotheker H, Nishimura I, Seerattan C. Laser-welded vs soldered nonprecious alloy dental bridges: a comparative study. Lasers Surg Med Suppl 1984; 4:207-13. [PMID: 6147733 DOI: 10.1002/lsm.1900040213] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The high cost of gold alloy has caused the dental profession to begin substituting nonprecious alloy for the framework in porcelain fused to metal bridges. Especially in long-span bridges it may be advantageous to make multiple castings and then join them for a better fit. As opposed to the highly successful soldering of gold, soldered nonprecious alloy bridges have a great failure rate in the mouth. Removal of and remaking of the bridges is thus the result. This study compares nonprecious units that have been laser-welded with those conventionally soldered. Seven identical bridges of three units were cast in a popular alloy composed of 74-78% nickel, 12-15% chromium, 4-6% molybdenum, and 1.8% maximum beryllium. One served as a control, while the remaining six were all cut in the same place. Of these, three were soldered with a gas oxygen torch. The other three were welded with a Nd-YAG laser. Better and stronger joints unlikely to fracture in the mouth were found with the laser-welded specimen.
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Hawbolt EB, MacEntee MI, Zahel JI. The tensile strength and appearance of solder joints in three base metal alloys made with high- and low-temperature solders. J Prosthet Dent 1983; 50:362-7. [PMID: 6137565 DOI: 10.1016/s0022-3913(83)80094-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Abstract
Successful presoldering of nonnoble alloys is variable at best. Under controlled conditions of joint gap distance, investing, and soldering, more than one third of the soldered joints are likely to fail. Furthermore, the recorded strength of successful solder joints was inconsistent. Improved heat application and controlled oxidation are required. Until new materials and/or techniques are developed, the soldering of nonnoble alloys prior to the application of porcelain is unwarranted.
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Abstract
A base metal alloy was soldered to precious and semiprecious alloys using a post-ceramic soldering technique. The specimens were tested by the tensile mode and the results statistically analyzed. The solder joints involving the base metal had strengths comparable to the precious and semiprecious joints. However, a high percentage of the base metal joints were too weak to be tested. Further study using other solders is indicated.
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Jendersen MD, Hamilton AI, Phillips RW, Ramfjord SP, Wolcott RB. Special report: report of the Committee on Scientific Investigation of the American Academy of Restorative Dentistry. J Prosthet Dent 1981; 45:643-69. [PMID: 6941017 DOI: 10.1016/0022-3913(81)90425-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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45
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MacEntee MI, Hawbolt EB, Zahel JI. The tensile and shear strength of a base metal weld joint used in dentistry. J Dent Res 1981; 60:154-8. [PMID: 6109740 DOI: 10.1177/00220345810600021101] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Samples of a base mental alloy were cast and welded together using a conventional welding procedure. The joints were loaded and placed either in a corrosive environment or in air for varying time periods. The tensile and shear strength of the joints was unaffected by the corrosive environment, and the joints, despite some internal defects, appeared suitable for clinical use.
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