Spss statistics for windows software ver 22

All statistical analyses were performed using the IBM SPSS Statistics for Windows software ver. 22.0 (IBM Corp., Armonk, NY, USA). Normality of data was analyzed using the Shapiro–Wilk test. Data with skewed distribution were analyzed using nonparametric tests. Differences in baseline or final data between two groups were analyzed using the independent t-test (Mann–Whitney U test for data showing skewed distribution) for numerical continuous data and the chi-square test for categorical data. Intergroup differences in all dependent variables were calculated and compared between groups using the independent t-test (Mann–Whitney U test for data showing skewed distribution). A p-value <0.05 was considered statistically significant.

An independent t-test and chi-square test were used to compare the two groups. The Spearman correlation analysis was performed to determine the association between the extent of anterior resorption and radiographic parameters. Statistical analyses were performed using IBM SPSS Statistics for Windows software ver. 22.0 (IBM Corp., Armonk, NY, USA), and p-values <0.05 were considered statistically significant.