Relação entre qualidade óssea clínica e radiográfica e a estabilidade primária de implantes curtos em região posterior

Abstract

Short implants have shown success rates similar to implants of conventional length, and both bone quality and initial stability of the receptor site of the implant may influence prognosis. Therefore, this study aimed to evaluate three methods of measuring implant stability - insertion torque (IT), Periotest (PTV) and Osstell (ISQ) - and the effect of bone quality evaluated during surgery (Leckholm and Zarb, 1985) and at images of multislice computed tomography (CT) or cone beam computed tomography (CBCT), assessed visually and by optical density (8bit grayscale), the primary stability of 45 short implants (Straumann SLActive® RN SP 4.1 x 6-mm long) placed in 20 patients at a private practice. All implants had screw-retained metaloceramic single crowns planned. One implant that showed ample mobility at the time of placement was not deployed and thus not entered into the statistical analysis. The significance level was set at 5%. Correlation was found (Spearman) between IT PTV x (-0.686), IT ISQ x (0.606) x ISQ and PTV (-0.627). Correlation was found between surgical bone quality and visual evaluation of CT / CBCT, but there was no correlation between surgical bone quality and optical density neither between visual evaluation of CT / CBCT and optical density. Primary stability of bone type 4 (evaluated surgically) was statistically lower when assessed by PTV, where the median for bones types 1-2, type 3 and type 4 were -5.0 (-6.0, -2.5), -3.0 (- 3.5, 1.5) and 2.5 (0.8, 5.3), respectively (p <0.001); ISQ average was 71.06 (+ / - 8.48) the type 1-2, 70.24 (+ / - 4.24) and 65.19 in type 3 (+ / - 8.38) in the type 4 (p <0.001) and IT, where 78.6% of type 4 bone implants placed had IT <15Ncm. Each implant obtained bone healing after 3 months. Thus, these results suggest that a moderate correlation between the measurements methods of primary stability (IT, PTV and ISQ) can be established and that the implants placed in type 4 bone get smaller initial stability than the other bone types. More studies are needed to validate methods for assessing bone for use in CT and CBCT.