Analytical and experimental position stability of the abutment in different dental implant systems with a conical implant–abutment connection

OBJECTIVES: Position stability of the abutment should be investigated in four implant systems with a conical implant–abutment connection. MATERIALS AND METHODS: Previously developed formulas and an established experimental setup were used to determine the position stability of the abutment in the four implant systems with a conical implant–abutment connection and different positional index designs: The theoretical rotational freedom was calculated by using the dimensions of one randomly selected implant per system for approximated geometric models. Experimentally, the rotation, the vertical displacement, and canting moments of the abutment after multiple repositioning and hand tightening of the abutment screw were investigated. RESULTS: The experimental rotation and vertical displacement differed between the implant systems tested. The analytical and experimental results for the rotation of the abutment clearly deviated in the three implant systems. CONCLUSIONS: Malpositioning of the abutment was possible in all the implant systems tested. Deviating theoretical and experimental results suggest high manufacturing tolerances during fabrication of the implant components. CLINICAL RELEVANCE: Position stability of the abutment is essential for precisely fitting implant-supported superstructures.