Spss statistic 27.0

The sample size calculation was done using the G*Power software, (version 3.1.9.6; Franz Faul, Universität Düsseldorf, Düsseldorf, Germany). A previous retreatment study^{21 (link)} using single-rooted teeth, was taken as reference to determine the effect size for the present study (i.e., 1.80). An alpha-type error of 0.05, a beta power of 0.95, and a ratio of N2/N1 = 1 were predetermined. Twelve specimens per group were specified as the ideal size.
The statistical analysis was realized using the IBM SPSS Statistic 27.0. software (SPSS Inc, Chicago, Illinois, EUA). The level of significance was set at 5% (p < 0.05). The Kolmogorov–Smirnov test was performed to test for data normality, which determined the use of Mann–Whitney test to compare the initial volume and aspect ratio between the two groups, and also to compare the volume of filling material remnants after NaOCl and EDTA agitation, and after the supplementary use of solvent. The time spent for the retreatment procedures including supplementary procedure were also compared using Mann–Whitney test.

After the sensory evaluation sessions, the collected data was remodeled with Microsoft Excel (Microsoft Office 2016) for further data treatment. The statistical analysis was performed with IBM SPSS Statistic 27.0 (IBM Corporation, Armonk, NY, USA). The number of participants who completed the whole series was for astringency N = 197 (8 excluded), pungency N = 199 (6 excluded), and cooling N = 198 (7 excluded). The zero samples (water) were excluded later from the analyses as being too mild for the test conditions due to the inconsistent evaluation by most of the participants. This was done based on previous tests and findings in the research project [14 (link)].