The comparison between implant stability quotient and bone-implant contact revisited: an experiment in Beagle dog.

BACKGROUND Resonance frequency analysis (RFA) is applied clinically for the assessment of implant stability, and the relevance of this application is widely accepted. However, the relationship between resonance frequency (RF) and other parameters of implant stability, such as the histomorphometrical bone-to-implant contact (BIC) parameter, has become controversial in the last decade. OBJECTIVE To analyse and clarify the controversial relationship between RF and histomorphometrical BIC measurements. MATERIAL AND METHODS A total of 36 dental implants (9 mm length, Ø 4.0 mm; Biohorizons(®) Implant Systems Inc., Birmingham, AL, USA) with a soluble blasting media (sandblasting with soluble particles) surface were implanted in six beagle dog mandibles. RFA assessments were performed with a magnetic Osstel Mentor(®) device at the time of implant installation, and during the monitoring period at weeks 1, 2, 4, 6 and 8, before implant retrieval. The dogs were sacrificed and the implants were removed in block after 8, 6, 4, 2, 1 and 0 weeks, respectively. One group was obtained at time 0, immediately after the implantation. The samples were embedded in methyl methacrylate polymers (Technovit(®) ) and cut along their long axis. BIC values were assessed by a non-subjective and systematic method based on backscattered scanning electron microscopy (BS-SEM) images. BIC% at the different time points was compared with the corresponding implant stability quotient (ISQ) values of the RFA assessment. RESULTS No statistically significant correlation between BIC and ISQ values (Osstell Mentor(®) ) was identified. The absence of a relationship between these two parameters is in agreement with several previous studies in humans and experimental animals. CONCLUSIONS The lack of correlation between BIC and ISQ values suggests that ISQ as determined by RFA is not able to identify the relationship between RF and histomorphometrical data.