Evaluation of the adaptation interface of one-piece implant-supported superstructures obtained in Ni-Cr-Ti and Pd-Ag alloys

Abstract

Several formulations of alternative alloys have been proposed for the substitution of gold-based alloys used in Dentistry. Recently, a Ni-Cr-Ti-based alloy has been introduced. The purpose of this work was to verify the marginal adaptation obtained with one-piece superstructures for implant-supported prostheses obtained in Ni-Cr-Ti alloy, compared to a semi-noble alloy Pd-Ag. Eight superstructures for each alloy were produced over 4 implants in the anterior region of the mandible. The superstructures were placed in a torquemeter and the fixation screw of implant #1 was tightened with a 20 Ncm load with the others loosened (Sheffield test). The unfitness (in mm) was measured using a three-dimensional optical measurer in each implant, in the buccal and lingual aspects. The obtained data were submitted to statistical analysis by the analysis of variance and Tukey's test at 5% level. Significant differences were found for the factors material (p≤0.05), with Ni-Cr-Ti pieces better than Pd-Ag ones, and implants (p≤0.01). There were no significant differences for the factor position and interactions among factors (p>0.05). Based on the analysis of the data, it is possible to conclude that the Ni-Cr-Ti alloy makes possible the obtainment of one-piece implant-supported superstructures with a smaller misfit compared to the one obtained in Pd-Ag alloy, traditionally indicated for this situation. Additional tests may verify the superiority of the Ni-CrTi alloy.

The effect of commercially pure titanium and alternative dental alloys on the marginal fit of one-piece cast implant frameworks

“…Better marginal fit achieved with Ni-Cr-Ti alloy than with PdAg alloy has already been reported in the literature. 31 Therefore, it could be possible to think about Ni-Cr-Ti alloys as a viable alternative. Nevertheless, it is important to be careful about the biocompatibility of these alloys.…”

“…Nickel is considered a critical metal because there are reports of carcinogenic potential and possible allergic reactions, and chromium has suspected carcinogenicity. 21,22,31 Studies compared semi-noble and noble alloys with some alternative alloys used in this study. 26,29,31 Titanium frameworks have been considered similar to gold alloy ones in relation to passive fit 29 and vertical fit.…”

“…21,22,31 Studies compared semi-noble and noble alloys with some alternative alloys used in this study. 26,29,31 Titanium frameworks have been considered similar to gold alloy ones in relation to passive fit 29 and vertical fit. 26 It means that it is perfectly possible to obtain accuracy of fit using non-precious alloys.…”

Reduction of chromium-vi by chromium resistant lactobacilli: A prospective bacterium for bioremediation

“…It has become one of the most abundant pollutants in aquatic and terrestrial ecosystems. [1] Hexavalent Cr (VI) and trivalent Cr (III) are two stable chromium oxidation states found in nature. As an analogue of sulfate, chromate can enter bacterial and mammalian cells readily via sulfate transport systems.…”

Oxidative damage induced by chromium (VI) in rat erythrocytes: protective effect of selenium

“…Industrial use, fuels burning, and waste incineration are sources of Cr in air as well as in water. Cr is non-biodegradable and persists in the environment [16,39]. Extensive studies on the industrial and environmental exposure to Cr compounds led the National Institute of Occupational Safety and Health to list chromate compounds as one of the major causes of occupational lung cancer.…”