2.5. Statistical Analysis
REGRESSION
Descriptive statistics (Mean, Median, SD, 95% CI, box plots) were generated for the insertion torque (ITV) and ISQ values for the DC and MAE groups. Furthermore, normality and equal variance steps were applied to determine the homogeneity of data distribution and to select the most appropriate parametric or non-parametric tests to investigate possible differences between DC and MAE for ITV and ISQ over time. The influence of implant macrogeometry (DC and MAE groups), location (maxilla and mandible), diameter (3.5 and 4.0 mm), length (9, 11, and 13 mm), and period (baseline, 30 days, and 45 days) to predict ITV and ISQ buccolingual and mesiodistal values were screened using multiple linear regression analysis. All the statistics were performed at the 5% significance level using dedicated software (SigmaStat for Windows version 4.0; Systat Software, Inc.). Graphs were generated using another program (MedCalc Statistical Software version 20.113 (MedCalc Software Ltd., Ostend, Belgium; Considering the two factors (implant design, arch type) as independent variables and the ISQ as the dependent variable, four groups are possible. The ANOVA sample size tool of SigmaStat provided the following: a minimum of 23 samples per group in the case of 8 ISQ points of difference while still considering a standard deviation value of 8 points. In the case SD values are 6 and the ISQ difference is 8, the minimum number per group would be 14 dental implants.