Abstract

LOARTE CAMPOS, Micarla et al. Adaptation of metallic copings made with two techniques: loss wax cast conventional centrifugation and soft milling block in CAD/CAM. Rev. Estomatol. Herediana [online]. 2017, vol.27, n.3, pp.163-175. ISSN 1019-4355.  http://dx.doi.org/10.20453/reh.v27i3.3200.

The new digitized technologies have allowed to improve the marginal and internal adaptation of a restoration, allowing to migrate from the technique of wax loss by centrifugation (CPC) to the additive and subtractive manufacture by CAD / CAM system soft milling block (SMB). Objective: To compare the marginal and internal discrepancies of Co-Cr alloy copings units on a chamfer termination line made with two techniques: CPC y SMB, determining which technique had better marginal and internal adaptation. Material and Methods: 13 Co-Cr alloy unit copings were fabricated for each technique to be evaluated. Silicon replication was used to evaluate the marginal and internal discrepancies. Each sample was cross-sectioned in the vestibular-palatine and mesio-distal directions, then the cervical, axial and occlusal zones were evaluated with a stereomicroscope. Results: The normality assumptions were evaluated with the Shapiro-Wilk test. Statistical analyzes were Student’s t test and U Mann-Whitney test. The SMB had a smaller marginal discrepancy in the vestibular-palatine sense compared to CPC, with a statistically significant difference (p <0.05), but in the mesio-distal sense the SMB had a smaller marginal discrepancy but no statistically significant difference (p <0.05). The lowest internal discrepancy was for CPC in the axial zone, both in the vestibular-palatine and mesio-distal directions, with a statistically significant difference (p <0.05), but in the occlusal area both in the vestibular-palatine and mesio-distal directions, The SMB with a statistically significant difference (p <0.05). Conclusions: The copings that presented a better marginal adaptation were those that were made by the SMB. The ones that presented better internal adaptation in the axial zone were the cofias realized by the CPC and in the occlusal zone the SMB presented better internal adaptation.

Keywords : Computer-aided design; adaptation; chromium alloys.

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