The Influence of Site Preparation (Countersinking) on Initial Dental Implant Stability. An in vitro Study Using Resonance Frequency Analysis

Primary implant stability is considered to be a critical factor for obtaining successful osseointegration [1]. Studies using Resonance Frequency Analysis (RFA) have demonstrated that initial implant stability is determined by the density of the bone, the surgical technique used, and the design of the implant [2, 3]. While different implant designs have shown similar results of higher stabilities in dense bone, initial stability can remarkably decrease in low density bone, and thereby jeopardize the osseointegration process [4]. Moreover, a recent clinical study with consecutively placed implants that were immediately loaded, showed a higher failure rate in low density bone, suggesting that primary stability is a major factor in the success of immediately loaded implants [5]. Consequently the question is how to improve implant stability in low density bone. Local bone density of the site via compression may be increased by altering the surgical technique. A recent study demonstrated that a modified surgical technique (less bone preparation) may influence primary implant stability in soft bone [6]. It has been suggested that countersinking (cervical flaring) of the implant site in type 3 and 4 bone may jeopardize the cortical bone anchorage and consequently affect primary implant stability [7]. However little has been published to date correlating primary implant stability to countersinking of the implant site. The purpose of the study is to test implant stability, using Resonance Frequency Analysis (RFA), in relation to surgical technique (countersinking of the implant site). MATERIALS AND METHODS