Statistical analysis
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REGRESSION
The data was collected and analyzed using statistical software (SPSS, version 22.0, IBM, IL, USA). For the in vitro data, the Kruskal-Wallis test was used to test the difference in the percentage of bacteria viability among the groups. Post hoc comparisons were performed using the Mann-Whitney U test with Bonferroni correction for multiple pairwise comparisons. For the clinical trial data, the Shapiro-Wilk test was used to determine the normality of the data. After 28 d, the GI and PI values of the 2 interventions were compared using analysis of covariance (ANCOVA), including their baseline scores as a covariate. The influence of potential confounders on the GI and PI was evaluated by linear regression. The satisfaction and compliance levels between the 2 types of toothbrushes were compared by the Wilcoxon Signed Rank test. The correlations between the order of the assigned toothbrushes, patients’ age, compliance scores, and satisfaction scores were evaluated using Spearman’s correlation coefficient. Significant differences were defined at 