Preparation protocol for oversized osteotomies (ODP)

This protocol repeated the steps of the standard protocol but then added a larger final drill. For the 3.3-mm implants, the final drill size was 3.2 mm; for the 3.75-mm implants, the final drill size was 3.65 mm (Fig. 2).

RFA

To analyze the data, an Osstell® SmartPeg threaded transducer (implant diameter 3.3 and 3.75 mm: SmartPeg Type 32 with a platform of 3.5 mm, Art-Nr. 100440; implant diameter 4.2 mm: SmartPeg Type 27 with a platform of 4.5 mm, Art-Nr. 10043; Osstell, Göteborg, Sweden) was screwed onto the implant fixture with the aid of a transporter. RFA was measured by Osstell® electronic analyzer (Osstell ISQ), positioned at a distance of 3 mm from the abutment. The recorded frequency was automatically converted into implant stability quotient (ISQ) values with a range of 0 to 100 (minimum to maximum stability). The mean ISQ values were calculated.

Torque in and torque out

Insertion torque and torque out were measured by using a customized handheld torque screwdriver with a digital output device (Mecmesin, Schwenningen, Germany) as described by Bolm et al.. Torque values were recorded in Newton centimeter.

Statistics

To analyze the differences between the measured value normality and homogeneity of variance tests (Levene statistic) were performed at first in order to check the conditions for the subsequent analysis. p values were obtained with either independent-samples t test or one-way ANOVA. In case of inhomogeneity of variance, a Welch-ANOVA was used instead. To obtain p values, post hoc multiple comparison Tukey test (equal variances assumed) or Games-Howell (equal variances not assumed) was used. The effect size was calculated as described in “Statistical power analysis for the behavioral sciences” by Jacob Cohen in 1988. Values are displayed as Cohen’s d and effect size (r). The statistical analyses were performed using SPSS version 24 for Windows (IBM, Armonk, New York). A p value ≤ 0.05 was termed significant. Values are displayed as mean plus standard deviation.