Evaluation of Marginal Misfit of Metal Frameworks Welded by Gas-Torch, Laser, and Tungsten Inert Gas Methods

Autor: Wilson Matsumoto, Paula Pastana Beraldo, Rossana Pereira de Almeida, Ana Paula Macedo, Beatriz Roque Kubata, Takami Hirono Hotta
Jazyk: angličtina
Rok vydání: 2018
Předmět:
Zdroj: International Journal of Dentistry, Vol 2018 (2018)
Druh dokumentu: article
ISSN: 1687-8728
1687-8736
DOI: 10.1155/2018/9828929
Popis: Purpose. The objective of this study was to evaluate the marginal fit and the flexural resistance of nickel-chromium frameworks welded by different techniques, gas-torch, laser, and tungsten inert gas (TIG), compared with that of frameworks made via one-piece casting. Methods. To evaluate the marginal fit, a master model was fabricated simulating four implants. Transfers and replicas were used to transfer the positions of the implants to the model, using a silicone matrix. The bars were waxed up and casted. Three assessments of misfit were performed for each implant using a stereomicroscope before and after welding in two predetermined regions, totaling six readings for each implant. To evaluate the flexural resistance, one group was made casting the specimens in one piece. Other 3 groups using gas-torch, laser, and TIG welding techniques were made after sectioned transversally. The data showed normal distribution and two-way ANOVA for marginal fit and one-way ANOVA for flexural resistance, and Tukey’s posttest (α=0.05) was performed. Results. For the marginal fit, the three welding methods presented similar results and were different from one-piece casting. For the flexural resistance, significant differences were observed among the studied groups (p
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