OBJECTIVE

To investigate the impact of progressive bone loss in an experimental peri‐implantitis model in the dog upon the implant stability quotient (ISQ) measured in the course of induced and spontaneous conditions of disease, and to evaluate the association between the clinical parameters and ISQ.

MATERIALS AND METHODS

Seventy‐two implants were placed in 12 Beagle dogs. Of these, 36 implants in six dogs were assessed during ligature‐induced peri‐implantitis (three timepoints) and at one timepoint following a period of spontaneous progres‐ sion. The ISQ was recorded using resonance frequency analysis (RFA). Furthermore,  the clinical peri‐implant parameters were registered at four sites per implant at each timepoint. Marginal bone loss (MBL) was determined using computed tomography at four sites per implant and bone‐to‐implant contact (BIC) was assessed from histologi‐ cal samples. A linear regression model was estimated by generalized estimation equations (GEEs) in order to study the MBL‐ISQ values at each measurement time‐ point. Pearson’s correlation test was applied.

RESULTS

None of the implants failed during the study period. At implant  level,  a strong  negative  correlation  was  found  for  all  timepoints  between  ISQ  and  MBL    (r = −0.58; p < 0.001). Accordingly, as follow‐up progressed, lower  ISQ  and  higher  MBL values were observed. A prediction of MBL depending on the ISQ values and timepoints showed a decrease in one ISQ unit to be related to ~1 mm of MBL. Likewise, a statistically significant correlation was found between BIC and ISQ evalu‐ ated after spontaneous chronification of peri‐implantitis (r = 0.34; p = 0.04). Nevertheless, the ISQ values failed to correlate to any of the clinical parameters recorded.

CONCLUSION

Resonance frequency analysis seems accurate in diagnosing progressive bone loss, as a statistically significant decrease in ISQ was recorded in the course of peri‐implant disease. Nevertheless, the clinical relevance of this observation as a di‐ agnostic tool is debatable, since implant stability remains high.