Abstract
Background and aims. Resonance frequency analysis (RFA) offers a noninvasive clinical measurement of stability and
osseointegration of implants; it is a useful tool to establish implant loading time. The RFA values are represented by a quantitative
unit called the Implant Stability Quotient (ISQ) on a scale from 1 to 100. The aim of the present study was to measure the
stability of Astra Tech and ITI dental implants during the healing period and determine the factors that affect the ISQ.
Materials and methods. In this study fourteen healthy subjects who were candidates for dental implants were randomly
divided into two groups. Group one received 15 Astra Tech and group two received 15 ITI dental implants. Bone type was
classified according to the Lekholm and Zarb index (D1-D4). RFA was used for direct measurement of implant stability on the
day of implant placement and 1, 3 and 6 months after implant placement. Data were analyzed by ANOVA, Student’s t-test and
Spearman rank correlation test using SPSS 11.5 with 95% confidence interval.
Results. The means of ISQ for Astra Tech implant after 3 and 6 months were significantly greater than those for ITI implant
(p<0.05). Statistical analysis showed higher ISQ values for mandible with Type I and Type II bone than maxilla and Type III
and Type IV bone (p<0.05); implant diameter was significantly correlated to implant stability (p<0.05).
Conclusion. Our data suggest that bone quality, implant surface texture (implant system) and diameter can affect implant
stability and loading time.