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Cumbo E, Gallina G, Messina P, Bilello G, Isaqali Karobari M, Scardina GA. Soldering in Dentistry: An Updated Technical Review. J Clin Med 2024; 13:809. [PMID: 38337503 PMCID: PMC10856638 DOI: 10.3390/jcm13030809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 12/29/2023] [Accepted: 01/29/2024] [Indexed: 02/12/2024] Open
Abstract
INTRODUCTION The need to permanently join two or more pieces of metal using heat is a frequent condition in various fields of medicine such as dentistry. Welding, brazing and soldering are permanent joining techniques between different metals that require in-depth background knowledge in order to obtain predictable results. AIM This review examines the different methods of joining metals using heat and their fields of application. DISCUSSION It is possible to create permanent metal joints in various phases of the creation of final products that will be used on the patient. In several cases, welds are also made directly by the manufacturer during industrial processing. In dentistry, dental laboratories perform complex welds mainly on dental prostheses and orthodontic appliances during the production process. It is also possible to obtain intraoral welding carried out by the clinician inside the patient's oral cavity. Welding can be carried out using combustible gases, electric current, infrared light and laser light through different technical procedures which must be chosen according to the specific needs and the metals to be joined. CONCLUSIONS It is useful for the dentist and dental technician to know the different welding methods, including those carried out in the factory by the manufacturer, to better understand the physical properties and mechanical resistance of the components marketed for the construction of prostheses and orthodontic appliances. The enormous variety of conditions in which those who practice welding can find themselves therefore presupposes in-depth knowledge in this field in order to apply the most suitable technique.
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Affiliation(s)
- Enzo Cumbo
- Department of Precision Medicine in Medical, Surgical and Critical Care (Me.Pre.C.C.), University of Palermo, 90133 Palermo, Italy; (E.C.); (G.G.); (P.M.); (G.B.)
| | - Giuseppe Gallina
- Department of Precision Medicine in Medical, Surgical and Critical Care (Me.Pre.C.C.), University of Palermo, 90133 Palermo, Italy; (E.C.); (G.G.); (P.M.); (G.B.)
| | - Pietro Messina
- Department of Precision Medicine in Medical, Surgical and Critical Care (Me.Pre.C.C.), University of Palermo, 90133 Palermo, Italy; (E.C.); (G.G.); (P.M.); (G.B.)
| | - Giuseppa Bilello
- Department of Precision Medicine in Medical, Surgical and Critical Care (Me.Pre.C.C.), University of Palermo, 90133 Palermo, Italy; (E.C.); (G.G.); (P.M.); (G.B.)
| | - Mohmed Isaqali Karobari
- Dental Research Unit, Center for Global Health Research, Saveetha Medical College and Hospital, Saveetha Institute of Medical and Technical Sciences, Chennai 600077, Tamil Nadu, India;
| | - Giuseppe Alessandro Scardina
- Department of Precision Medicine in Medical, Surgical and Critical Care (Me.Pre.C.C.), University of Palermo, 90133 Palermo, Italy; (E.C.); (G.G.); (P.M.); (G.B.)
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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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Lee SY, Lee JH. Effect of soldering techniques and gap distance on tensile strength of soldered Ni-Cr alloy joint. J Adv Prosthodont 2011; 2:117-21. [PMID: 21264189 PMCID: PMC3024500 DOI: 10.4047/jap.2010.2.4.117] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2010] [Revised: 09/15/2010] [Accepted: 12/01/2010] [Indexed: 11/24/2022] Open
Abstract
PURPOSE The present study was intended to evaluate the effect of soldering techniques with infrared ray and gas torch under different gap distances (0.3 mm and 0.5 mm) on the tensile strength and surface porosity formation in Ni-Cr base metal alloy. MATERIALS AND METHODS Thirty five dumbbell shaped Ni-Cr alloy specimens were prepared and assigned to 5 groups according to the soldering method and the gap distance. For the soldering methods, gas torch (G group) and infrared ray (IR group) were compared and each group was subdivided by corresponding gap distance (0.3 mm: G3 and IR3, 0.5 mm: G5, IR5). Specimens of the experimental groups were sectioned in the middle with a diamond disk and embedded in solder blocks according to the predetermined distance. As a control group, 7 specimens were prepared without sectioning or soldering. After the soldering procedure, a tensile strength test was performed using universal testing machine at a crosshead speed 1 mm/min. The proportions of porosity on the fractured surface were calculated on the images acquired through the scanning electronic microscope. RESULTS Every specimen of G3, G5, IR3 and IR5 was fractured on the solder joint area. However, there was no significant difference between the test groups (P > .05). There was a negative correlation between porosity formation and tensile strength in all the specimens in the test groups (P < .05). CONCLUSION There was no significant difference in ultimate tensile strength of joints and porosity formations between the gas-oxygen torch soldering and infrared ray soldering technique or between the gap distance of 0.3 mm and 0.5 mm.
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Affiliation(s)
- Sang-Yeob Lee
- Department of Prosthodontics, College of Dentistry, Dankook University, Cheonan, Korea
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TIOSSI R, FALCÃO-FILHO H, AGUIAR JÚNIOR FA, RODRIGUES RC, MATTOS MDG, RIBEIRO RF. Modified section method for laser-welding of ill-fitting cp Ti and Ni-Cr alloy one-piece cast implant-supported frameworks. J Oral Rehabil 2010; 37:359-63. [DOI: 10.1111/j.1365-2842.2010.02063.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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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]
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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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Lynch CD, McConnell RJ. Accurately locating the components of a fixed partial denture prior to soldering the connector: an intraoral technique. J Prosthet Dent 2002; 87:460-1. [PMID: 12011864 DOI: 10.1067/mpr.2002.122012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Christopher D Lynch
- Department of Restorative Dentistry, National University of Ireland, Wilton, Cork, Ireland.
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Mejia R, Tobon SM. Marginal fit of metal ceramic restorations subjected to a standardized postsoldering technique. J Prosthet Dent 2000; 83:535-9. [PMID: 10793385 DOI: 10.1016/s0022-3913(00)70011-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The fit of a fixed partial denture (FPD) is fundamental for the clinical success of a restoration. When a postsoldering procedure is needed, a high-precision laboratory technique is necessary to not affect the fit of the FPD. This article evaluates whether a standardized postsoldering technique affected the marginal fit of a 3-unit high palladium alloy FPD. One hundred and eight measurements were made of 3-unit FPDs, fabricated in a high palladium alloy (2% Au-79% Pd-10% Cu-8% Ga) and constructed on 9 tin dies in vitro. After the castings were fabricated, specimens were measured at 3 specific points per abutment (distal, labial, lingual) before and after soldering. Differences were found in the marginal opening of both copings, before soldering (49.9 microm) and after soldering (48. 3 microm). There was no significant difference in the adaptation of the copings after the soldering procedure (P<.05).
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Affiliation(s)
- R Mejia
- Health Science Institute CES, Faculty of Dentistry, Medellín, Colombia.
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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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Taylor JC, Hondrum SO, Prasad A, Brodersen CA. Effects of joint configuration for the arc welding of cast Ti-6Al-4V alloy rods in argon. J Prosthet Dent 1998; 79:291-7. [PMID: 9553882 DOI: 10.1016/s0022-3913(98)70240-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
STATEMENT OF PROBLEM Titanium and its alloys are more commonly used in prosthodontics and welding has become the most common modality for their joining. Studies on the welding of titanium and its alloys have not quantified this value, though its importance has been suggested. PURPOSE This study compared the strength and properties of the joint achieved at various butt joint gaps by the arc-welding of cast Ti-6Al-4V alloy tensile bars in an argon atmosphere. MATERIAL AND METHODS Forty of 50 specimens were sectioned and welded at four gaps. All specimens underwent tensile testing to determine ultimate tensile strength and percentage elongation, then oxygen analysis and scanning electron microscopy. RESULTS As no more than 3 samples in any group of 10 actually fractured in the weld itself, a secondary analysis that involved fracture location was initiated. There were no differences in ultimate tensile strength or percentage elongation between specimens with weld gaps of 0.25, 0.50, 0.75, and 1.00 mm and the as-cast specimens. There were no differences in ultimate tensile strength between specimens fracturing in the weld and those fracturing in the gauge in welded specimens; however, as-cast specimens demonstrated a higher ultimate tensile strength than welded specimens that fractured in the weld. Specimens that fractured in the weld site demonstrated less ductility than those that fractured in the gauge in both welded and as-cast specimens, as confirmed by scanning electron microscopy examination. The weld wire showed an oxygen scavenging effect from the as-cast parent alloy. CONCLUSIONS The effects of the joint gap were not significant, whereas the characteristics of the joint itself were, which displayed slightly lower strength and significantly lower ductility (and thus decreased toughness). The arc-welding of cast titanium alloy in argon atmosphere appears to be a reliable and efficient prosthodontic laboratory modality producing predictable results, although titanium casting and joining procedures must be closely controlled to minimize heat effects and oxygen contamination.
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Affiliation(s)
- J C Taylor
- Division of Prosthodontics, Faculty of Dentistry, Dalhousie University, Halifax, Canada
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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. Mechanical properties of metal connectors soldered by gas torch versus an infrared technique. J Prosthodont 1993; 2:103-9. [PMID: 7902170 DOI: 10.1111/j.1532-849x.1993.tb00390.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
PURPOSE The ultimate tensile strength and percentage elongation of solder joints of three alloy systems were tested. MATERIALS AND METHODS Solder joints were formed using either an infrared soldering machine or gas-oxygen torch. Intact solder materials were used as controls. RESULTS There were no significant differences in percentage elongation among different treatment methods of the solders or among various solder materials. All intact solder materials possessed significantly higher ultimate tensile strength than the joints made with either method. For high-noble and noble alloy solders, there were no significant differences in ultimate tensile strength of joints made with either method. For base metal alloy solder, the ultimate tensile strength of joints made with the infrared technique was significantly higher than that made with the gas-oxygen torch technique. CONCLUSIONS The infrared technique can be used as an alternative to the gas-torch technique for soldering high-noble and noble alloys. It is superior to the gas-torch technique for soldering a cobalt-chromium alloy.
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Affiliation(s)
- A C Cheng
- Advanced Education Prosthodontics, Northwestern University Dental School, Chicago, Il 60611
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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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20
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Abstract
This laboratory study compared the seating of one-piece castings with that of soldered fixed partial dentures. Two investments were investigated, five American Dental Association type III and five metal ceramic alloy fixed partial dentures were made by using the conventional indirect technique. The investing and casting protocol was designed to produce an ideal fit of the individual complete crown abutments, not the fixed partial denture. Independent seating of each retainer provided a baseline measurement for complete seating and was compared with fixed partial denture seating. Fixed partial dentures were then sectioned and reassembled by soldering twice, using a low- and high-expansion investment. Statistical evaluation identified significant differences between the metals and the techniques. Marginal discrepancies with one-piece casting and lower (0.6%) thermal-expansion soldering were clinically unacceptable. A clinically acceptable fit was obtained with the higher (1%) thermal-expansion soldering investment.
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Affiliation(s)
- A G Gegauff
- Section of Restorative and Prosthetic Dentistry, Ohio State University, College of Dentistry, Columbus
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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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22
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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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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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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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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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29
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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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30
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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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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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Abstract
The soldering index serves to record the precise alignment of the separate parts of a fixed partial prosthesis as positioned on the abutments. The use of an all-acrylic resin index is not as accurate as a plaster index. When impression plaster is used alone, it is difficult to place minimal coverage retainers such as inlays back into the index. This article describes a simple method that may overcome the difficulty without sacrificing the dimensional accuracy inherent in a plaster index.
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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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36
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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
Both high- and low-heat removable partial denture alloys were soldered with combinations of different solders and heat sources. The soldered specimens were subjected to tensile strength testing, and a ranking of joint strength was developed. Joint strengths that were 85% as strong as the as-cast metal were created in both alloy types when 0.800 fine solder was used with an electrosoldering device as a heat source. All other combinations tested resulted in greater reductions in joint strength.
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38
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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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39
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Abstract
A repeatable post-soldering technique for a nonprecious alloy has been described. With proper metal design, nonprecious alloy crowns can be soldered in a standard vacuum porcelain furnace. Scanning electron micrographs and EDXA confirm that a good union has taken place between the gold solder and nickel alloy.
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40
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Abstract
In identifying the criteria which influence soldering distortion, the results of this study indicate the following: 1. Linear distortion identified at the investment phase (a net increase in gap distance) is due to setting expansion of the plaster and soldering investment. 2. The linear distortion identified at the soldering phase (a net decrease in gap distance) occurs because of the contraction of the solder. 3. The rotational distortions measured were found to be minimal. 4. The use of a minimum gap distance, without contact, is desirable. 5. Adding solder results in a well-rounded, solid solder joint.
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Staffanou RS, Radke RA, Jendresen MD. Strength properties of soldered joints from various ceramic-metal combinations. J Prosthet Dent 1980; 43:31-9. [PMID: 6101287 DOI: 10.1016/0022-3913(80)90349-2] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Rasmussen EJ, Goodkind RJ, Gerberich WW. An investigation of tensile strength of dental solder joints. J Prosthet Dent 1979; 41:418-23. [PMID: 34035 DOI: 10.1016/0022-3913(79)90039-8] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Tensile specimens of dental solder joints were tested to determine the effect of gap distance on the strength of solder joints. Two dental alloys were used; a Type III gold alloy and a gold-palladium (Au-Pd) alloy. The Type III alloy was joined with the recommended gold solder. The Au-Pd alloy was joined using preceramic and postceramic application soldering techniques. Gap distances of 0.13 mm, 0.5 mm, and 1 mm were used with each soldering technique. All solder specimens were machined to a uniform diameter and then tested for tensile strength. It was concluded that: 1. There was a significant increase in strength for the Type III gold as the gap distance was increased. 2. The trend toward stronger joints at narrow gap distances for Au-Pd alloy joined with presolder was not statistically significant. 3. The trend toward stronger joints at wide gap distances for the Au-Pd alloy joined with the postsolder was not statistically significant. 4. The postsolder joints were statistically stronger than the presolder joints. 5. The trends observed could be partially explained in terms of competing effects of yield strength (triaxially), wettability, and void or inclusion content at the various gap distances.
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43
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Blustein R, DePaul BM, Barnhart RC, Green KA. A reliable technique of post soldering of nonprecious ceramic units. J Prosthet Dent 1976; 36:112-4. [PMID: 9506 DOI: 10.1016/0022-3913(76)90241-9] [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: 12/12/2022]
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