Spss software windows version 22

Pearson's chi-square test was used to evaluate the relationships between the outcome/dependent variable (the presence of VRF in the teeth) and various independent variable (the demographic factor and clinical factors). The prevalence of VRF in endodontic surgery was used as the key outcome variable. As the dependent variable was dichotomous (having VRF/not having VRF), a binary logistic regression model was performed to determine the association between VRF and its clinical associated factors such as the tooth characteristics (age, gender and tooth type) and iatrogenic risk factors in dental procedures (history of root canal treatment, restoration and post). A test was considered statistically significant if its two-tailed P-value was <0.05. Odds ratio (OR) and 95% confidence intervals (95%CI) were considered, and the data were analyzed using the IBM SPSS Software Windows version 22.0.

Continuous data are reported as mean±standard deviation (SD) or standard error, whereas discrete (categorical) data are presented as number and percentage. Mean comparisons between 2 groups were done using the Mann Whitney test. The Kruskal-Wallis test was used for nonparametric data as opposed to the 1-way analysis of variance test to compare 3 or more groups based on a dependent variable that is measured on at least an ordinal level. Correlations were done using Spearman's rho correlation analysis. Receiver operating characteristic (ROC) curve analysis was designed to calculate the area under the curve (AUC). Cutoffs were determined by the Youden Index. Analyses were performed on SPSS software (Windows version 22.0) (IBM Corp, Chicago, IL).