2.4. Statistical Analysis
caries’
All the data were input into a spreadsheet (Microsoft Excel 2021 for Mac, version 16.4.8). A chi-square test was performed for CTNI changes between experimental groups and follow-up examinations; moreover, tests for trends across ordered experimental groups were tested using the Cuzick’s test trends.Cox Proportional Hazards models were run to assess the factors associated with caries’ change of status. Estimates are reported in the hazard ratio (HR) and their respective 95% confidence interval (95% CI). The Kaplan–Meier estimator was endorsed to estimate the survival fraction of teeth measured as the change of status during the trial. The Efron method was used to handle tied failures. The Greenwood’s formula was used to approximate the variance of the Kaplan–Meier estimator. For all statistical analyses, the statistical significance was set at α = 0.05.