In Vitro Assessment of Primary Stability of Straumann® Implant Designs

Abstract

Primary implant stability (PS) is one of the main factors influencing implant survival rate. Several methods to determine the PS have been used, such as Periotest values (PVs) and resonance frequency analysis (RFA) with implant stability quotient (ISQ) values. The aim of this study was to compare different implant designs in regard to PS assessed by Periotest and RFA in vitro. A total of 90 implants were placed in freshly slaughtered cow ribs. The implants (Straumann®, Institute Straumann AG, Basel, Switzerland; length 10 mm, ø3.3 mm) had the following three designs: Bone Level (BL, 30 implants), Standard Plus (SP, 30 implants), and Tapered Effect (TE, 30 implants). Before implant placement, the investigator was calibrated for every design according to the manufacturer's instructions. An independent observer, blinded to the study, assessed the accuracy of placement. RFA based on the Osstell device and PVs were performed after abutment connection. One-way analysis of variance and Tukey's post hoc test were used for statistical evaluation. All implants were mechanically stable. The mean PV for BL was -4.67(± 1.18), for SP, -6.07(± 0.94), and for TE, -6.57(± 0.57). The mean ISQ values were 75.02(± 3.65), 75.98(± 3.00), and 79.83(± 1.85), respectively. The one-way ANOVA showed significant difference among three implant designs in PV (p < .0001) and for the ISQ between BL/TE or SP/TE implants (p < .0001). In addition, the Tukey's (pair-wise comparison) test showed significant differences in PV and RFA between the BL/T (p < .0001). Within the limitations of this study, higher implant stability was found for tapered designed implants.