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Thus, this study aimed to evaluate the influence of different nucleation heat treatments on the crystalline fraction and crystal morphology of the LS2 LaMaV CAD. Discs (12 mm diameter x 1.2 mm thickness) of LS2 LaMaV CAD and IPS e.max CAD (C, control group, n=3) were made. LS2 LaMaV CAD discs were annealed at 380oC/2h followed by different nucleation heat treatments in which time and temperature were varied composing 4 groups (n=3): T1 (1h30/500oC), T2 (3h/500oC), T3 (6h/500oC) and T4 (6h/480oC). Scanning Electron Microscopy images were obtained to characterize the microstructure and to quantify the crystalline fraction using the ImageJ software. X-ray diffraction with Rietveld refinement was performed. ANOVA one-way with Tukey post-hoc test (a = 0.05) was used to analyze the ImageJ images and the Rietveld refinements for X-ray diffraction data. X-ray diffraction analysis showed peaks of approximately 86% of lithium disilicate for all groups. The morphology of crystals was in lath-shaped and homogeneous format for all groups; the group that most resembled the C group was T1. The crystalline fraction (%) was: C = 59.33 ± 0.47, T1 = 61.63 ± 0.61, T2 = 61.07 ± 1.09, T3 = 56.39 ± 0.32, and T4 = 57.48 ± 0.90, all the groups were statistically different to the C group. It was concluded that the nucleation temperature influenced the size and quantity of the crystals of lithium disilicate; treatment that showed the best result was that that received nucleation treatment for 1 hour and 30 minutes at 500ºC.

The authors have withdrawn this preprint due to author disagreement.