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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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Perveen A, Molardi C, Fornaini C. Applications of Laser Welding in Dentistry: A State-of-the-Art Review. MICROMACHINES 2018; 9:E209. [PMID: 30424142 PMCID: PMC6187655 DOI: 10.3390/mi9050209] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 04/23/2018] [Accepted: 04/25/2018] [Indexed: 12/13/2022]
Abstract
The dental industry without lasers is inconceivable right now. This captivating technology has outlasted other possible alternative technologies applied in dentistry in the past due to its precision, accuracy, minimal invasive effect as well as faster operating time. Other alternatives such as soldering, resistance (spot) welding, plasma (torch) welding, and single pulse tungsten inert gas welding have their pros and cons; nevertheless, laser welding remains the most suitable option so far for dental application. This paper attempts to give an insight into the laser principle and types of lasers used for dental purposes, types of dental alloys used by the dentist, and effect of laser parameters on prosthesis/implants. It is apparent from the literature review that laser assisted dental welding will continue to grow and will become an unparalleled technology for dental arena.
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Affiliation(s)
- Asma Perveen
- Mechanical Engineering, Nazarbayev University, Astana 010000, Kazakhstan.
| | - Carlo Molardi
- Electrical & Electronics Engineering, Nazarbayev University, Astana 010000, Kazakhstan; .
| | - Carlo Fornaini
- Department of Engineering and Architecture, University of Parma, Parma, I-43124, Italy.
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Lee JH, Choi SK, Hong MH. The metallurgical characteristics of non-precious alloys using Nd:YAG laser welding. Biomater Res 2015; 19:25. [PMID: 26635967 PMCID: PMC4668671 DOI: 10.1186/s40824-015-0047-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Accepted: 11/04/2015] [Indexed: 11/19/2022] Open
Abstract
Background This study aimed to determine the effect of hardness change according to penetration depth in the laser fusing zone and observed the correlation of the microstructure as an Nd:YAG laser was irradiated to Ni-Cr alloy for dental use by setting the spot diameter size with respect to defocusing distances. In all groups, the hardness depth profiles in the laser fusing zone and heat-affecteded zone (HAZ) had larger values than those of the base metal. In addition, the hardness values in places beyond the fusing zone and the HAZ were measured as being quantitatively lower. Methods The alloys used in this study were Verabond 2 V, Noritake Super, and Bellabond Plus, which are commercially used non-precious dental alloys. The specimens were cut to have a plate shape with a size of 0.5 × 3.0 × 2.5 mm. This was followed by setting the Nd:YAG laser output, pulse duration, and frequency to 60 W, 10 ms, and 5 Hz, respectively. The laser was then irradiated as the spot diameter condition varied between 0.5 mm and 1.4 mm in accordance with defocusing distance from 0.0 mm to 2.0 mm. After the laser irradiation, a cross-section of the fusing zone in the specimens was observed in terms of laser melted depth, hardness depth profile, and the microstructure of each alloy. Results The observation result of the diffusion of the constituent elements and microstructure using field emission scanning electron microscopy, energy dispersive spectroscopy (EDS), and electron probe micro-analyzer showed that the fusing zone revealed a much finer dendritic form than the base metal due to the self-quenching effect after laser melting, while no change in constituent elements was found although some evaporation of the main elements was observed. Conclusions These results suggest that each Mo and Si combined inter-metallic compounds were formed on the interdendritic area. Through this study, the laser fusing zone had better hardenability due to the inter-metallic compound and grain refinement effect.
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Affiliation(s)
- Jun-Hee Lee
- Department of Advanced Materials Engineering, Dong-A University, Busan, Korea
| | - Seok-Kyu Choi
- Department of Advanced Materials Engineering, Dong-A University, Busan, Korea
| | - Min-Ho Hong
- Department of Bio-medical Research Institute, Kyungpook National University Hospital, Daegu, Korea
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Kokolis J, Chakmakchi M, Theocharopoulos A, Prombonas A, Zinelis S. Mechanical and interfacial characterization of laser welded Co-Cr alloy with different joint configurations. J Adv Prosthodont 2015; 7:39-46. [PMID: 25722836 PMCID: PMC4341185 DOI: 10.4047/jap.2015.7.1.39] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Revised: 09/16/2014] [Accepted: 09/18/2014] [Indexed: 11/18/2022] Open
Abstract
PURPOSE The mechanical and interfacial characterization of laser welded Co-Cr alloy with two different joint designs. MATERIALS AND METHODS Dumbbell cast specimens (n=30) were divided into 3 groups (R, I, K, n=10). Group R consisted of intact specimens, group I of specimens sectioned with a straight cut, and group K of specimens with a 45° bevel made at the one welding edge. The microstructure and the elemental distributions of alloy and welding regions were examined by an SEM/EDX analysis and then specimens were loaded in tension up to fracture. The tensile strength (TS) and elongation (ε) were determined and statistically compared among groups employing 1-way ANOVA, SNK multiple comparison test (α=.05) and Weibull analysis where Weibull modulus m and characteristic strength σο were identified. Fractured surfaces were imaged by a SEM. RESULTS SEM/EDX analysis showed that cast alloy consists of two phases with differences in mean atomic number contrast, while no mean atomic number was identified for welded regions. EDX analysis revealed an increased Cr and Mo content at the alloy-joint interface. All mechanical properties of group I (TS, ε, m and σο) were found inferior to R while group K showed intermediated values without significant differences to R and I, apart from elongation with group R. The fractured surfaces of all groups showed extensive dendritic pattern although with a finer structure in the case of welded groups. CONCLUSION The K shape joint configuration should be preferred over the I, as it demonstrates improved mechanical strength and survival probability.
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Affiliation(s)
- John Kokolis
- Department of Biomaterials, School of Dentistry, National and Kapodistrian, University of Athens, Greece. ; Department of Dental Technology, Technological Educational Institution of Athens, Greece
| | | | | | - Anthony Prombonas
- Department of Dental Technology, Technological Educational Institution of Athens, Greece
| | - Spiros Zinelis
- Department of Biomaterials, School of Dentistry, National and Kapodistrian, University of Athens, Greece
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Bock JJ, Bailly J, Fuhrmann RA. Effects of different brazing and welding methods on the fracture load of various orthodontic joining configurations. J Orthod 2014; 36:78-84. [PMID: 19487737 DOI: 10.1179/14653120722986] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Affiliation(s)
- Jens J Bock
- Martin Luther University of Halle Wittenberg, Halle, Germany.
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Mechanical properties of thin films of laser-welded titanium and their associated welding defects. Lasers Med Sci 2014; 29:1799-805. [PMID: 23636297 DOI: 10.1007/s10103-013-1334-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2012] [Accepted: 04/18/2013] [Indexed: 10/26/2022]
Abstract
The aim of this study was to evaluate the mechanical properties of thin films of laser-welded cast titanium using an interference strain/displacement gauge (ISDG) and to analyze factors that affect laser welding. Dog-bone-shaped small specimens of cast titanium were prepared by wire cutting after they were laser-welded. The specimens were divided into three groups according to the gap distance of the laser weld; the control was non-welded titanium. Small specimens without cast defects detected by X-ray screening were measured by a tensile test machine using ISDG, and stress-strain curves were drawn. Finally, the fracture texture was analyzed. The ultimate tensile strengths (UTSs) of specimens with a gap distance of 0.00, 0.25, and 0.50 mm were 492.16 ± 33.19, 488.09 ± 43.18, and 558.45 ± 10.80 MPa, respectively. There were no significant differences in UTS between the test groups and the control group (p > 0.05). However, the plastic deformation and the percent elongation increased as the gap distance increased. Incomplete penetration defects appeared in groups that had small gap distances, which may have affected the properties of the laser-welded titanium. However, the welding material was still pure titanium. These results suggest that an appropriate gap distance should be maintained to improve the application of dental laser welding.
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Bertrand C, Poulon-Quintin A. Temporal pulse shaping: a key parameter for the laser welding of dental alloys. Lasers Med Sci 2014; 30:1457-64. [PMID: 24913424 DOI: 10.1007/s10103-014-1606-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Accepted: 05/28/2014] [Indexed: 11/26/2022]
Abstract
This study aims to describe the effect of pulse shaping on the prevention of internal defects during laser welding for two dental alloys mainly used in prosthetic dentistry. Single spot, weld beads, and welds with 80 % overlapping were performed on Co-Cr-Mo and Pd-Ag-Sn cast plates with a pulsed neodymium-doped yttrium aluminum garnet (Nd:YAG) laser. A specific welding procedure using adapted parameters to each alloy was completed. All the possibilities for pulse shaping were tested: (1) the square pulse shape as a default setting, (2) a rising edge slope for gradual heating, (3) a falling edge slope to slow the cooling process, and (4) a combination of rising and falling edges. The optimization of the pulse shape is supposed to produce defect-free welds (crack, pores, voids). Cross-section SEM observations and Vickers microhardness measurements were made. Pd-Ag-Sn was highly sensitive to hot cracking, and Co-Cr-Mo was more sensitive to voids and small porosities (sometimes combined with cracks). Using a slow cooling ramp allowed a better control on the solidification process for those two alloys always preventing internal defects. A rapid slope should be preferred for Co-Cr-Mo alloys due to its low-laser beam reflectivity. On the opposite, for Pd-Ag-Sn alloy, a slow rising slope should be preferred because this alloy has a high-laser beam reflectivity.
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Affiliation(s)
- Caroline Bertrand
- Institut de la Chimie de la Matière Condensée de Bordeaux (ICMCB), C.N.R.S., UPR9048, Université Bordeaux, 87 Avenue du Dr. Albert Schweitzer, 33608, Pessac, France,
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Temperature changes of pulp chamber during in vitro laser welding of orthodontic attachments. ScientificWorldJournal 2014; 2014:589461. [PMID: 24550714 PMCID: PMC3914460 DOI: 10.1155/2014/589461] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2013] [Accepted: 10/24/2013] [Indexed: 11/30/2022] Open
Abstract
The use of lasers has been suggested for orthodontists to fabricate or repair orthodontic appliances by welding metals directly in the mouth. This work aimed to evaluate the temperature changes in the pulp chamber during welding of an orthodontic wire to an orthodontic molar band using Nd : YAG laser in vitro. A freshly extracted human third molar with eliminated pulpal tissues was used. J-type thermocouple wire was positioned in the pulp chamber. A conductor gel was used in the transferring of outside temperature changes to the thermocouple wire. An orthodontic band was applied to the molar tooth and bonded using light cured orthodontic cement. Twenty five mm length of 0.6 mm diameter orthodontic stainless steel wires was welded to the orthodontic band using Nd : YAG laser operated at 9.4 watt. Temperature variation was determined as the change from baseline temperature to the highest temperature was recorded during welding. The recorded temperature changes were between 1.8 and 6.8°C (mean: 3.3 ± 1.1°C). The reported critical 5.5°C level was exceeded in only one sample. The results of this study suggest that intraoral use of lasers holds great potential for the future of orthodontics and does not present a thermal risk. Further studies with larger samples and structural analysis are required.
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TAKAYAMA Y, NOMOTO R, NAKAJIMA H, OHKUBO C. Effects of argon gas flow rate on laser-welding. Dent Mater J 2012; 31:316-26. [PMID: 22447067 DOI: 10.4012/dmj.2011-158] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Yasuko TAKAYAMA
- Department of Removable Prosthodontics, Tsurumi University School of Dental Medicine
| | - Rie NOMOTO
- Department of Dental Engineering, Tsurumi University School of Dental Medicine
| | | | - Chikahiro OHKUBO
- Department of Removable Prosthodontics, Tsurumi University School of Dental Medicine
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Takayama Y, Nomoto R, Nakajima H, Ohkubo C. Comparison of joint designs for laser welding of cast metal plates and wrought wires. Odontology 2011; 101:34-42. [PMID: 22080283 DOI: 10.1007/s10266-011-0049-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2011] [Accepted: 10/24/2011] [Indexed: 11/29/2022]
Abstract
The purpose of the present study was to compare joint designs for the laser welding of cast metal plates and wrought wire, and to evaluate the welded area internally using X-ray micro-focus computerized tomography (micro-CT). Cast metal plates (Ti, Co-Cr) and wrought wires (Ti, Co-Cr) were welded using similar metals. The specimens were welded using four joint designs in which the wrought wires and the parent metals were welded directly (two designs) or the wrought wires were welded to the groove of the parent metal from one or both sides (n = 5). The porosity and gap in the welded area were evaluated by micro-CT, and the maximum tensile load of the welded specimens was measured with a universal testing machine. An element analysis was conducted using an electron probe X-ray microanalyzer. The statistical analysis of the results was performed using Bonferroni's multiple comparisons (α = 0.05). The results included that all the specimens fractured at the wrought wire when subjected to tensile testing, although there were specimens that exhibited gaps due to the joint design. The wrought wires were affected by laser irradiation and observed to melt together and onto the filler metal. Both Mo and Sn elements found in the wrought wire were detected in the filler metal of the Ti specimens, and Ni was detected in the filler metal of the Co-Cr specimens. The four joint designs simulating the designs used clinically were confirmed to have adequate joint strength provided by laser welding.
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Affiliation(s)
- Yasuko Takayama
- Department of Removable Prosthodontics, Tsurumi University School of Dental Medicine, 2-1-3 Tsurumi, Tsurumi-ku, Yokohama, Japan.
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Nomoto R, Takayama Y, Tsuchida F, Nakajima H. Non-destructive three-dimensional evaluation of pores at different welded joints and their effects on joints strength. Dent Mater 2010; 26:e246-52. [PMID: 20828805 DOI: 10.1016/j.dental.2010.08.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2009] [Revised: 03/12/2010] [Accepted: 08/09/2010] [Indexed: 10/19/2022]
Abstract
OBJECTIVES The purpose of this study was to measure the porosity in different laser welded cast alloys non-destructively using X-ray micro-focus computerized tomography (micro-CT) and to evaluate the effect of porosity on the tensile strength of the welded joints. MATERIALS AND METHODS The welding procedure was conducted in rectangular cast metals, CoCr, Ti and platinum added gold alloy (AuPt). The metal plates were butted CoCr to CoCr (CoCr/CoCr) or Ti to Ti (Ti/Ti) for welding of similar metals and Ti to AuPt (Ti/AuPt) for welding of dissimilar metals. Specimens were welded under several laser-welding conditions; with groove (normal), without groove (no groove), spatter, crack, or no overlapped welding (no overlap) (n=5). Porosity in the welded area was evaluated using a micro-CT. Tensile strength of the welded specimens was measured at a crosshead speed of 1mm/min. Multiple comparisons of the group means were performed using ANOVA and Fisher's multiple comparisons test (α=.05). The relationship between the porosity and the tensile strength was investigated with a regression analysis. RESULTS Three-dimensional images of Ti/AuPt could not be obtained due to metal artifacts and the tensile specimens of Ti/AuPt were debonded prior to the tensile test. All other welded specimens had porosity in the welded area and the porosities ranged from 0.01% to 0.17%. The fractures of most of the CoCr/CoCr and Ti/Ti specimens occurred in the parent metals. Joint strength had no relationship with the porosity in the welded area (R(2)=0.148 for CoCr/CoCr, R(2)=0.088 for Ti/Ti, respectively). SIGNIFICANCE The small amount of porosity caused by the laser-welding procedures did not affect the joint strength. The joint strength of Ti/AuPt was too weak to be used clinically.
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Affiliation(s)
- Rie Nomoto
- Department of Dental Engineering, Tsurumi University School of Dental Medicine, 2-1-3 Tsurumi, Tsurumi-ku, Yokohama 230-8501, Japan.
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Bertrand C, Poulon-Quintin A. Proposals for optimization of laser welding in prosthetic dentistry. J Prosthodont 2009; 19:69-76. [PMID: 19780906 DOI: 10.1111/j.1532-849x.2009.00523.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
This paper points out each key parameter involved in laser welding and discusses the parameters' effects on weld microstructure and defects detected inside the weld. Solutions are proposed to adjust the parameters to provide an optimal dental assembly. Metallurgical effects as well as defects are briefly discussed. A welding procedure adapted to different compositions of dental alloys is proposed.
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Affiliation(s)
- Caroline Bertrand
- Department of Prosthodontics, TELEO, University of Nice Sophia-Antipolis, Nice, France.
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Fornaini C, Bertrand C, Bonanini M, Rocca JP, Nammour S. Welding in the Dental Office by Fiber-Delivered Laser: A New Technique. Photomed Laser Surg 2009; 27:417-23. [PMID: 19569953 DOI: 10.1089/pho.2008.2273] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Carlo Fornaini
- TELEO Laboratory, Faculty of Dentistry, University of Nice-Sophia Antipolis, Nice, France
- Dental School, Faculty of Medicine, University of Parma, Parma, Italy
- Department of Dental Sciences, Faculty of Medicine, University of Liège, Liège, Belgium
| | - Caroline Bertrand
- TELEO Laboratory, Faculty of Dentistry, University of Nice-Sophia Antipolis, Nice, France
| | - Mauro Bonanini
- Dental School, Faculty of Medicine, University of Parma, Parma, Italy
| | - Jean-Paul Rocca
- TELEO Laboratory, Faculty of Dentistry, University of Nice-Sophia Antipolis, Nice, France
| | - Sam Nammour
- Department of Dental Sciences, Faculty of Medicine, University of Liège, Liège, Belgium
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Fornaini C, Bertrand C, Rocca JP, Mahler P, Bonanini M, Vescovi P, Merigo E, Nammour S. Intra-oral laser welding: an in vitro evaluation of thermal increase. Lasers Med Sci 2009; 25:473-7. [PMID: 19322623 DOI: 10.1007/s10103-009-0666-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2008] [Accepted: 03/02/2009] [Indexed: 11/29/2022]
Abstract
The neodymium:yttrium-aluminium-garnet (Nd:YAG) laser is currently used in dental laboratories to weld metals on dental prostheses. Recently, the use of Nd:YAG has been suggested so that dentists themselves can repair broken fixed, removable and orthodontic prostheses by welding metals directly in the mouth. This work aimed to evaluate, through a four k-type thermocouple system on calf jaws, the thermal increase in the biological structures close to the metal parts during laser welding. We put two hemispherical metal plates onto mandibular molars and then laser welded them at three points with a four k-thermocouple system to determine the thermal rise in the pulp chamber, sulcus, root and bone. This procedure was carried out on 12 samples, and the results were processed. The highest values of thermal increase were found in the pulp chamber, 1.5 degrees C; sulcus, 0.7 degrees C; root, 0.3 degrees C; and bone, 0.3 degrees C. This study showed that thermal increases in pulp chamber, sulcus, root and bone were biologically compatible and that intra-oral laser welding, at the parameters used in this work, seems to be harmless to the biological structures close to the welding and thermally affected zones.
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Affiliation(s)
- C Fornaini
- Department of Dental Sciences, Faculty of Medicine, University of Liege, Liege, Belgium.
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Bock JJ, Bailly J, Gernhardt CR, Fuhrmann RAW. Fracture strength of different soldered and welded orthodontic joining configurations with and without filling material. J Appl Oral Sci 2009; 16:328-35. [PMID: 19089229 PMCID: PMC4327598 DOI: 10.1590/s1678-77572008000500005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2008] [Accepted: 04/18/2008] [Indexed: 11/22/2022] Open
Abstract
The aim of this study was to compare the mechanical strength of different joints made by conventional brazing, TIG and laser welding with and without filling material. Five standardized joining configurations of orthodontic wire in spring hard quality were used: round, cross, 3 mm length, 9 mm length and 7 mm to orthodontic band. The joints were made by five different methods: brazing, tungsten inert gas (TIG) and laser welding with and without filling material. For the original orthodontic wire and for each kind of joint configuration or connecting method 10 specimens were carefully produced, totalizing 240. The fracture strengths were measured with a universal testing machine (Zwick 005). Data were analyzed by ANOVA (p=0.05) and Bonferroni post hoc test (p=0.05). In all cases, brazing joints were ruptured on a low level of fracture strength (186-407 N). Significant differences between brazing and TIG or laser welding (p<0.05, Bonferroni post hoc test) were found in each joint configuration. The highest fracture strength means were observed for laser welding with filling material and 3 mm joint length (998 N). Using filling materials, there was a clear tendency to higher mean values of fracture strength in TIG and laser welding. However, statistically significant differences were found only in the 9-mm long joints (p<0.05, Bonferroni post hoc test). In conclusion, the fracture strength of welded joints was positively influenced by the additional use of filling material. TIG welding was comparable to laser welding except for the impossibility of joining orthodontic wire with orthodontic band.
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Affiliation(s)
- Jens Johannes Bock
- Department of Orthodontics, Martin-Luther-University Halle, Wittenberg, Germany
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Bock JJ, Fraenzel W, Bailly J, Gernhardt CR, Fuhrmann RAW. Influence of different brazing and welding methods on tensile strength and microhardness of orthodontic stainless steel wire. Eur J Orthod 2008; 30:396-400. [PMID: 18617503 DOI: 10.1093/ejo/cjn022] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Jens Johannes Bock
- Department of Orthodontics, University School of Dental Medicine, Martin-Luther-University Halle-Wittenberg, Halle/Saale, Germany.
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Bertrand C, Laplanche O, Rocca JP, Le Petitcorps Y, Nammour S. Effect of the combination of different welding parameters on melting characteristics of grade 1 titanium with a pulsed Nd-Yag laser. Lasers Med Sci 2007; 22:237-44. [PMID: 17308957 DOI: 10.1007/s10103-006-0438-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2006] [Accepted: 12/18/2006] [Indexed: 10/23/2022]
Abstract
The laser is a very attractive tool for joining dental metallic alloys. However, the choice of the setting parameters can hardly influence the welding performances. The aim of this research was to evaluate the impact of several parameters (pulse shaping, pulse frequency, focal spot size...) on the quality of the microstructure. Grade 1 titanium plates have been welded with a pulsed Nd-Yag laser. Suitable power, pulse duration, focal spot size, and flow of argon gas were fixed by the operator. Five different pulse shapes and three pulse frequencies were investigated. Two pulse shapes available on this laser unit were eliminated because they considerably hardened the metal. As the pulse frequency rose, the metal was more and more ejected, and a plasma on the surface of the metal increased the oxygen contamination in the welded area. Frequencies of 1 or 2 Hz are optimum for a dental use. Three pulse shapes can be used for titanium but the rectangular shape gives better results.
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Affiliation(s)
- C Bertrand
- Department of Restorative Dentistry and Endodontics (Nice Sophia-Antipolis, France), Laboratoire LASIO, 06357, Nice Cedex, France.
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Zupancic R, Legat A, Funduk N. Tensile strength and corrosion resistance of brazed and laser-welded cobalt-chromium alloy joints. J Prosthet Dent 2006; 96:273-82. [PMID: 17052472 DOI: 10.1016/j.prosdent.2006.08.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
STATEMENT OF PROBLEM The longevity of prosthodontic restorations is often limited due to the mechanical or corrosive failure occurring at the sites where segments of a metal framework are joined together. PURPOSE The purpose of this study was to determine which joining method offers the best properties to cobalt-chromium alloy frameworks. Brazed and 2 types of laser-welded joints were compared for their mechanical and corrosion characteristics. MATERIAL AND METHODS Sixty-eight cylindrical cobalt-chromium dental alloy specimens, 35 mm long and 2 mm in diameter, were cast. Sixteen specimens were selected for electrochemical measurements in an artificial saliva solution and divided into 4 groups (n=4). In the intact group, the specimens were left as cast. The specimens of the remaining 3 groups were sectioned at the center, perpendicular to the long-axis, and were subsequently rejoined by brazing (brazing group) or laser welding using an X- or I-shaped joint design (X laser and I laser groups, respectively). Another 16 specimens were selected for electrochemical measurements in a more acidic artificial saliva solution. These specimens were also divided into 4 groups (n=4) as described above. Electrochemical impedance spectroscopy and potentiodynamic polarization were used to assess corrosion potentials, breakdown potentials, corrosion current densities, total impedances at lowest frequency, and polarization charge-transfer resistances. The remaining 36 specimens were used for tensile testing. They were divided into 3 groups in which specimen pairs (n=6) were joined by brazing or laser welding to form 70-mm-long cylindrical rods. The tensile strength (MPa) was measured using a universal testing machine. Differences between groups were analyzed using 1-way analysis of variance (alpha=.05). The fracture surfaces and corrosion defects were examined with a scanning electron microscope. RESULTS The average tensile strength of brazed joints was 792 MPa and was significantly greater (P<.05) than the tensile strength of both types of laser-welded joints (404 MPa and 405 MPa). When laser welding was used, successful joining was limited to the peripheral aspects of the weld. The welding technique did not significantly affect the joint tensile strength. Electrochemical measurements indicated that the corrosion resistance of the laser-welded joints was better than of the brazed ones, primarily due to differences in passivation ability. CONCLUSION Laser welding provides excellent corrosion resistance to cobalt-chromium alloy joints, but strength is limited due to the shallow weld penetration. Brazed joints are less resistant to corrosion but have higher tensile strength than laser welds.
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Affiliation(s)
- Rok Zupancic
- Department of Prosthodontics, University of Ljubljana, Faculty of Medicine, Division of Dental Medicine, Slovenia.
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Meyer JM. Reducing the variations in laser welding. Br Dent J 2004. [DOI: 10.1038/sj.bdj.4811135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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