Does intraoperative bone density testing correlate with parameters of primary implant stability? A pilot study in minipigs

Abstract

Objectives: Bone density, surgical protocol, and implant design are the major deter-minants of primary stability. The goal of this animal trial was to investigate potentialcorrelations of intraoperative bone density testing with clinical and histologic param-eters of primary implant stability.Material and methods: Following extractions of all mandibular premolars and subse-quent healing, four implants each were placed in a total of four minipigs. Bone den-sity was determined by applying intraoperative compressive tests using a devicenamed BoneProbe whereas measurements of implant insertion torque and resonancefrequency analysis were used for evaluating implant stability. Bone mineral density(BMD) and bone to implant contact were quantified after harvesting mandibularblock sections. Spearman rank correlation tests were performed for evaluating corre-lations (α = .05).Results: Due to variation in clinical measurements, only weak correlations could beidentified. A positive correlation was found between the parameters bone to implantcontact and BMD (Spearman's rho .53; p=.05) whereas an inverse correlation wasobserved between BMD and implant stability (Spearman's rho −.61; p=.03). BothBoneProbe measurements in the cortical and trabecular area positively correlatedwith implant insertion torque (Spearman's rho 0.60; p=.02). A slightly stronger corre-lation was observed between the average of both BoneProbe measurements andimplant insertion torque (Spearman's rho.66; p=.01).Conclusions: While establishing exact relationships among parameters of implant sta-bility and the measurement techniques applied would require greater sample size,intraoperative compressive testing of bone might, despite the weak correlations seenhere, be a useful tool for predicting primary implant stability.