Modification of clinically short Locator abutments using laser welding.

As dental implants continue to survive longer, managing and maintaining implant prostheses can be complicated by the lack of compatible parts or the discontinuation of implant systems. This report describes a laser welding procedure for the management of clinically short Locator abutments (Zest Anchors Inc) that lacked a commercially available, compatible alternative.

Cytotoxic outcomes of orthodontic bands with and without silver solder in different cell lineages.

INTRODUCTION: The safety of orthodontic materials is a matter of high interest. In this study, we aimed to assess the in-vitro cytotoxicity of orthodontic band extracts, with and without silver solder, by comparing the viability outcomes of the HaCat keratinocytes, the fibroblastic cell lineages HGF and MRC-5, and the kidney epithelial Vero cells. METHODS: Sterilized orthodontic bands with and without silver solder joints were added to culture media (6 cm2/mL) and incubated for 24 hours at 37°C under continuous agitation. Subsequently, the cell cultures were exposed to the obtained extracts for 24 hours, and an assay was performed to evaluate the cell viability. Copper strip extracts were used as positive control devices. RESULTS: The extracts from orthodontic bands with silver solder joints significantly reduced the viability of the HaCat, MRC-5, and Vero cell lines, whereas the viability of HGF was not altered by this material. Conversely, the extracts of orthodontic bands without silver solder did not significantly modify the viability index of all evaluated cell lines. CONCLUSIONS: Except for HGF fibroblasts, all tested cell lines showed decreased viability percentages after exposure to extracts of orthodontic bands containing silver solder joints. These data show the relevance of testing the toxicity of orthodontic devices in different cell lines.

Temporal pulse shaping: a key parameter for the laser welding of dental alloys.

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.

Laser and plasma dental soldering techniques applied to Ti-6Al-4V alloy: ultimate tensile strength and finite element analysis.

STATEMENT OF PROBLEM: The literature provides limited information regarding the performance of Ti-6Al-4V laser and plasma joints welded in prefabricated bars in dental applications. PURPOSE: The purpose of this study was to evaluate the mechanical strength of different diameters of Ti-6Al-4V alloy welded with laser and plasma techniques. MATERIAL AND METHODS: Forty-five dumbbell-shaped rods were created from Ti-6Al-4V and divided into 9 groups (n=5): a control group with 3-mm and intact bars; groups PL2.5, PL3, PL4, and PL5 (specimens with 2.5-, 3-, 4-, and 5-mm diameters welded with plasma); and groups L2.5, L3, L4, and L5 (specimens with 2.5-, 3-, 4-, and 5-mm diameters welded with laser). The specimens were tested for ultimate tensile strength (UTS), and elongation percentages (EP) were obtained. Fractured specimens were analyzed by stereomicroscopy, and welded area percentages (WAP) were calculated. Images were made with scanning electron microscopy. In the initial analysis, the data were analyzed with a 2-way ANOVA (2×4) and the Tukey Honestly Significant Difference (HSD) test. In the second analysis, the UTS and EP data were analyzed with 1-way ANOVA, and the Dunnett test was used to compare the 4 experimental groups with the control group (α=.05). The Pearson and Spearman correlation coefficient tests were applied to correlate the study factors. Finite element models were developed in a workbench environment with boundary conditions simulating those of a tensile test. RESULTS: The 2-way ANOVA showed that the factors welding type and diameter were significant for the UTS and WAP values. However, the interaction between them was not significant. The 1-way ANOVA showed statistically significant differences among the groups for UTS, WAP, and EP values. The Dunnett test showed that all the tested groups had lower UTS and EP values than the control group. The 2.5- and 3-mm diameter groups showed higher values for UTS and WAP than the other test groups. A positive correlation was found between welded area percentage and UTS and a negative correlation between these parameters and the diameters of the specimens. No statistically significant difference was found between the weld techniques. CONCLUSIONS: Under the experimental conditions described, diameters of 2.5 and 3 mm resulted in higher UTS and WAP for both laser and plasma welding and appear to be the best option for joining prefabricated rods in this kind of union.

Effect of joint design and welding type on the flexural strength and weld penetration of Ti-6Al-4V alloy bars.

STATEMENT OF PROBLEM: Framework longevity is a key factor for the success of complete-arch prostheses and commonly depends on the welding methods. However, no consensus has been reached on the joint design and welding type for improving framework resistance. PURPOSE: The purpose of this study was to assess the effect of different joint designs and welding methods with tungsten inert gas (TIG) or laser to join titanium alloy bars (Ti-6Al-4V). MATERIAL AND METHODS: Seventy titanium alloy bar specimens were prepared (3.18 mm in diameter × 40.0 mm in length) and divided into 7 groups (n=10): the C-control group consisting of intact specimens without joints and the remaining 6 groups consisting of specimens sectioned perpendicular to the long-axis and rejoined using an I-, X30-, or X45-shaped joint design with TIG welding (TI, TX30, and TX45) or laser welding (LI, LX30, and LX45). The specimens were tested with 3-point bending. The fracture surfaces were first evaluated with stereomicroscopy to measure the weld penetration area and then analyzed with scanning electron microscopy (SEM). The data were statistically analyzed with 2-way ANOVA and the Tukey post hoc test, 1-way ANOVA and the Dunnett test, and the Pearson correlation test (α=.05). RESULTS: Specimens from the X30 and X45 groups showed higher flexural strength (P<.05) and welded area (P<.05) than specimens from the I groups, regardless of the welding type. TIG welded groups showed significantly higher flexural strength than the laser groups (P<.05), regardless of the joint design. TIG welding also resulted in higher welded areas than laser welding for the I-shaped specimens. No significant differences were found for the weld penetration area in the X45 group, either for laser or TIG welding. SEM analysis showed more pores at the fracture surfaces of the laser specimens. Fracture surfaces indicative of regions of increased ductility were detected for the TIG specimens. CONCLUSIONS: TIG welding resulted in higher flexural strength for the joined titanium specimens than laser welding. For both welding methods, X30- and X45-shaped joint designs resulted in higher flexural strength and welding penetration than the I-shaped joint design.

Corrosion in artificial saliva of a Ni-Cr-based dental alloy joined by TIG welding and conventional brazing.

STATEMENT OF THE PROBLEM: Fixed prosthesis and partial dental prosthesis frameworks are usually made from welded Ni-Cr-based alloys. These structures can corrode in saliva and have to be investigated to establish their safety. PURPOSE: The purpose of this study was to evaluate the corrosion behavior of joints joined by tungsten inert gas (TIG) welding and conventional brazing in specimens made of commercial Ni-Cr alloy in Fusayama artificial saliva at 37°C (pH 2.5 and 5.5). MATERIAL AND METHODS: Eighteen Ni-Cr base metal specimens were cast and welded by brazing or tungsten inert gas methods. The specimens were divided into 3 groups (base metal, 2 welded specimens), and the composition and microstructure were qualitatively evaluated. The results of potential corrosion and corrosion current density were analyzed with a 1-way analysis of variance and the Tukey test for pairwise comparisons (α=.05). RESULTS: Base metal and tungsten inert gas welded material showed equivalent results in electrochemical corrosion tests, while the air-torched specimens exhibited low corrosion resistance. The performance was worst at pH 2.5. CONCLUSIONS: These results suggest that tungsten inert gas is a suitable welding process for use in dentistry, because the final microstructure does not reduce the corrosion resistance in artificial saliva at 37°C, even in a corrosion-testing medium that facilitates galvanic corrosion processes. Moreover, the corrosion current density of brazed Ni-Cr alloy joints was significantly higher (P<.001) than the base metal and tungsten inert gas welded joints.

Replacing worn overdenture abutments of an unknown implant system by using laser welding: a clinical report.

This clinical report describes a procedure for replacing worn ball abutments with low-profile resilient abutments by using laser welding when the implant system for a mandibular implant-supported overdenture could not be identified.

Conventional prosthodontic management of partial edentulism with a resilient attachment-retained overdenture in a patient with a cleft lip and palate: a clinical report.

Recent advances in surgery and orthodontics have resulted in improvements in the management of patients with a cleft lip or palate. Early surgical intervention and bone-grafting procedures have frequently been used to ensure closure of the cleft and continuity of the alveolar bone. However, a need for the prosthodontic management of patients with a cleft palate still exists. Most frequently, the indication is to restore the edentulous spaces located anteriorly in the vicinity of the residual cleft defect. In addition to improving the esthetic outcome, prosthodontic management also is required to restore function, especially occlusion and speech. This clinical report illustrates the management of an adult patient with a unilateral cleft of the lip and palate who required prosthodontic rehabilitation after surgery. The patient had previously undergone multiple surgeries and did not want to consider implant therapy as a treatment option. Thus, the patient was managed with fixed and removable prosthodontics with a maxillary overdenture prosthesis retained by microextracoronal resilient attachments, which were laser welded onto crowns on abutment teeth to obtain a functionally and esthetically acceptable result.

Strength properties of preceramic brazed joints of a gold-palladium alloy with a microwave-assisted oven and gas/oxygen torch technique.

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.

Effects of soldering methods on tensile strength of a gold-palladium metal ceramic alloy.

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.

Comparison of implant-abutment interface misfits after casting and soldering procedures.

The aim of this study was to compare vertical and horizontal adjustments of castable abutments after conducting casting and soldering procedures. Twelve external hexagonal implants (3.75 × 10 mm) and their UCLA abutments were divided according their manufacturer and abutment type: PUN (plastic UCLA, Neodent), PUC (plastic UCLA, Conexão), PU3i (plastic UCLA, Biomet 3i), and PUTN (plastic UCLA with Tilite milled base, Neodent). Three infrastructures of a fixed partial implant-supported bridge with 3 elements were produced for each group. The measurements of vertical (VM) and horizontal (HM) misfits were obtained via scanning electron microscopy after completion of casting and soldering. The corresponding values were determined to be biomechanically acceptable to the system, and the results were rated as a percentage. Statistical analysis establishes differences between groups by chi-square after procedures, and McNeman's test was applied to analyze the influence of soldering over casting (α ≤ .05). For the values of VM and HM, respectively, when the casting process was complete, it was observed that 83.25% and 100% (PUTN), 33.3% and 27.75% (PUN), 33.3% and 88.8% (PUC), 33.3% and 94.35% (PU3i) represented acceptable values. After completing the requisite soldering, acceptable values were 50% and 94.35% (PUTN), 16.6% and 77.7% (PUN), 38.55% and 77.7% (PUC), and 27.75% and 94.35% (PU3i). Within the limitations of this study, it can be concluded that the premachined abutments presented more acceptable VM values. The HM values were within acceptable limits before and after the soldering procedure for most groups. Further, the soldering procedure resulted in an increase of VM in all groups.

A comparison of two soldering techniques on the misfit of bar-retained implant-supported overdentures.

PURPOSE: This study was conducted to measure and compare the effect of the soldering method (torch soldering or ceramic furnace soldering) used for soldering bars to bar-retained, implant-supported overdentures on the fit between the bar gold cylinder and implant transgingival abutment. MATERIALS AND METHODS: Thirty-two overdenture implant bars were manufactured and screw retained into two Bränemark implants, which were attached to a cow rib. The bars were randomly distributed in two groups: a torch-soldering group and a porcelain-furnace soldering group. Then all bars were cut and soldered using a torch and a ceramic furnace. The fit between the bar gold cylinders and implant transgingival abutments was measured with a light microscope on the opposite side to the screw tightening side before and after the bar soldering procedure. The data obtained were statistically processed for paired and independent data. RESULTS: The average misfit for all bars before soldering was 33.83 to 54.04 µm. After cutting and soldering the bars, the misfit increased up to a range of 71.74 to 78.79 µm. Both before and after the soldering procedure, the bars soldered using a torch showed a higher misfit when compared to the bars soldered using a porcelain furnace. After the soldering procedure, the misfit was slightly lower on the left side of the bars, which had been soldered using a ceramic furnace. CONCLUSIONS: According to our data, the soldering of bars using the torch or furnace oven soldering techniques does not improve the misfit of one-piece cast bars on two implants. The lower misfit was obtained using the porcelain furnace soldering technique.

Comparison of joint designs for laser welding of cast metal plates and wrought wires.

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.

Effect of framework soldering on the deformation of implant abutments after framework seating: a study with strain gauges.

INTRODUCTION: Passive fit has been considered an important requirement for the longevity of implant-supported prostheses. Among the different steps of prostheses construction, casting is a feature that can influence the precision of fit and consequently the uniformity of possible deformation among abutments upon the framework connection. PURPOSE: This study aimed at evaluating the deformation of abutments after the connection of frameworks either cast in one piece or after soldering. MATERIALS AND METHODS: A master model was used to simulate a human mandible with 5 implants. Ten frameworks were fabricated on cast models and divided into 2 groups. Strain gauges were attached to the mesial and distal sides of the abutments to capture their deformation after the framework's screw retentions were tightened to the abutments. RESULTS: The mean values of deformation were submitted to a 3-way analysis of variance that revealed significant differences between procedures and the abutment side. The results showed that none of the frameworks presented a complete passive fit. CONCLUSION: The soldering procedure led to a better although uneven distribution of compression strains on the abutments.

A six-year follow-up of full-arch immediate restorations fabricated with an intraoral welding technique.

PURPOSE: The aim of this study was to evaluate the 6-year effectiveness of maxillary and mandibular full-arch immediately loaded prostheses fabricated using an intraoral welding technique. METHODS: All patients received the same day of surgery a fixed, full-arch prosthesis supported by an intraorally welded titanium framework created directly in the patient's mouth using a titanium bar. Life table analysis of implant survival, complications, and any other adverse events were recorded at yearly follow-up for a period of 6 years. RESULTS: One hundred twenty-four (86.11%) of 144 implants placed in maxillary cases and 87 (77.68%) of 112 implants placed in mandible cases completed the planned 6-year follow-up. At the 72-month follow-up, the accumulated mean marginal bone loss was, respectively, 1.39 mm (SD = 0.67) for the implants placed in the maxilla (n = 124) and 1.29 mm (SD = 0.71) for the implants placed in the mandible (n = 87). Fracturing of the composite resin superstructure was the most common adverse event. CONCLUSIONS: After a 6-year follow-up period, the intraoral welding technique proved to be a predictable technique for successfully rehabilitating the fully edentulous patient with a fixed and immediate prosthesis.

Selection patterns of dietary foods in edentulous participants rehabilitated with maxillary complete dentures opposed by mandibular implant-supported prostheses: a multicenter longitudinal assessment.

STATEMENT OF PROBLEM: Documentation of long-term changes in food intake is lacking for those treated with a maxillary complete denture opposed by a mandibular, screw-retained, implant-supported fixed prosthesis. PURPOSE: The purpose of this study was to evaluate the selection patterns of dietary foods over 5 years for edentulous participants treated in a multicenter prospective clinical trial that compared cast alloy versus laser-welded titanium frameworks of an implant-supported prostheses opposed by maxillary complete dentures to rehabilitate edentulous participants. MATERIAL AND METHODS: The study assessed data from a multicenter prospective clinical trial that followed edentulous participants from an initial baseline of wearing existing complete dentures to implant placement, restoration with a mandibular implant-supported prosthesis opposed by a maxillary complete denture, to follow-up assessment of these treatments over 5 years. The 32 participants in the cohort were treated at 5 of 9 participating centers. The data collected included 2 dietary forms, a standardized 4-day food diary form, and a dietary habits questionnaire. Each participant completed forms before entering into treatment (control) and at the 1- and 5-year follow-up assessment after being treated with a maxillary complete denture opposing a mandibular complete-arch fixed implant-supported prosthesis. Descriptive statistics were calculated for each measure at each assessment point. Regression analysis and the Sign test were used to calculate change in the participants' nutritional status (α=.05). RESULTS: Among the findings, it was noted that difficulty in masticating hard, raw, and fibrous foods decreased and intake of vegetable portions increased significantly from 2.5 to 3.3 servings. Participant comfort in eating in public places and their enjoyment of eating were significantly improved from 50% of participants being uncomfortable with their prior complete denture treatment to only 4% after 5 years. CONCLUSIONS: Within the limitations of this study, it was concluded that vegetable intake and ability to masticate raw, hard, and fibrous food for these participants improved when they received a mandibular implant-supported prosthesis opposed by a maxillary complete denture. According to the analysis and findings, the overall eating experience was more pleasurable, and eating in public was more comfortable after replacement of complete dentures with a mandibular implant-supported prosthesis.

Managing dislodged locator from a titanium alloy implant bar in an implant-supported bar overdenture: a clinical report.

An implant-supported prosthesis is a successful treatment option for edentulous patients. This article reports on a case that has not been documented in the literature involving complications in a maxillary implant-supported bar overdenture, followed by the management of the complications.

Evaluation of fit of cement-retained implant-supported 3-unit structures fabricated with direct metal laser sintering and vacuum casting techniques.

This study evaluated the vertical discrepancy of implant-fixed 3-unit structures. Frameworks were constructed with laser-sintered Co-Cr, and vacuum-cast Co-Cr, Ni-Cr-Ti, and Pd-Au. Samples of each alloy group were randomly luted in standard fashion using resin-modified glass-ionomer, self-adhesive, and acrylic/urethane-based cements (n = 12 each). Discrepancies were SEM analyzed. Three-way ANOVA and Student-Newman-Keuls tests were run (P < 0.05). Laser-sintered structures achieved the best fit per cement tested. Within each alloy group, resin-modified glass-ionomer and acrylic/urethane-based cements produced comparably lower discrepancies than the self-adhesive agent. The abutment position did not yield significant differences. All misfit values could be considered clinically acceptable.

Comparative analysis of different joining techniques to improve the passive fit of cobalt-chromium superstructures.

STATEMENT OF PROBLEM: The influence of different joining techniques on passive fit at the interface structure/abutment of cobalt-chromium (Co-Cr) superstructures has not yet been clearly established. PURPOSE: The purpose of this study was to compare 3 different techniques of joining Co-Cr superstructures by measuring the resulting marginal misfit in a simulated prosthetic assembly. MATERIAL AND METHODS: A specially designed metal model was used for casting, sectioning, joining, and measuring marginal misfit. Forty-five cast bar-type superstructures were fabricated in a Co-Cr alloy and randomly assigned by drawing lots to 3 groups (n=15) according to the joining method used: conventional gas-torch brazing (G-TB), laser welding (LW), and tungsten inert gas welding (TIG). Joined specimens were assembled onto abutment analogs in the metal model with the 1-screw method. The resulting marginal misfit was measured with scanning electron microscopy (SEM) at 3 different points: distal (D), central (C), and mesial (M) along the buccal aspect of both abutments: A (tightened) and B (without screw). The Levene test was used to evaluate variance homogeneity and then the Welsch ANOVA for heteroscedastic data (α=.05). RESULTS: Significant differences were found on abutment A between groups G-TB and LW (P=.013) measured mesially and between groups G-TB and TIG (P=.037) measured centrally. On abutment B, significant differences were found between groups G-TB and LW (P<.001) and groups LW and TIG (P<.001) measured mesially; groups G-TB and TIG (P=.007) measured distally; and groups G-TB and TIG (P=.001) and LW and TIG (P=.007) measured centrally. CONCLUSIONS: The method used for joining Co-Cr prosthetic structures had an influence on the level of resulting passive fit. Structures joined by the tungsten inert gas method produced better mean results than did the brazing or laser method.

Fatigue strength: effect of welding type and joint design executed in Ti-6Al-4V structures.

BACKGROUND: This study evaluated the fatigue strength of Ti-6Al-4V-machined structures submitted to laser (L)-welding and TIG (TIG)-welding procedures, varying the joint designs. MATERIALS AND METHODS: Seventy dumbbell rods were machined in Ti-6Al-4V alloy with central diameters of 3.5 mm. The specimens were sectioned and welded using TIG or L and three joint designs {'I' design, varying welding distances [0.0 mm (I00) or 0.6 mm (I06)], or 'X' [X] design}. The combinations of variables created six groups, which, when added to the intact group, made a total of seven groups (n = 10). L was executed as follows: 360 V/8 ms (X) and 390 V/9 ms (I00 and I06), with focus and frequency regulated to zero. TIG was executed using 2:2 (X) and 3:2 (I00 and I06) as welding parameters. Joints were finished, polished and submitted to radiographic examination to be analysed visually for the presence of porosity. The specimens were then subjected to mechanical cyclic tests, and the number of cycles completed until failure was recorded. The fracture surface was examined using a scanning electron microscope. RESULTS: The Kruskal-Wallis and Dunn test (α = 0.05) indicated that the number of cycles resisted for fracture was higher to X for both welding procedures. To L, I06 was as resistant as X. The Mann-Whitney U-test (α = 0.05) indicated that L joints were more resistant than TIG to I00 and I06. Spearman's correlation coefficient (α = 0.05) indicated a negative correlation between the number of cycles and presence of porosity. CONCLUSION: Thus, to weld Ti-6Al-4V structures, the best condition is X, independent of the welding method employed.