Objective.This study was designed to explore relationships of resonance frequency analysis (RFA)ââ?¬â?assessed implant stability (ISQ\nvalues)with bonemorphometric parameters and bone quality in an ex vivomodel of dental implants placed inhumanfemoral heads\nand to evaluate the usefulness of this model for dental implant studies. Material and Methods. This ex vivo study included femoral\nheads from 17 patients undergoing surgery for femoral neck fracture due to osteoporosis (OP) (n = 7) or for total prosthesis joint\nreplacement due to severe hip osteoarthrosis (OA) (n = 10). Sixty 4.5 Ã?â?? 13mm Dentsply Astra implants were placed, followed by\nRFA. CD44 immunohistochemical analysis for osteocytes was also carried out. Results. As expected, the analysis yielded significant\neffects of femoral head type (OA versus OA) (P < 0.001), but not of the implants (P = 0.455) or of the interaction of the two factors\n(P = 0.848). Bonferroni post hoc comparisons showed a lower mean ISQ for implants in decalcified (50.33 Ã?± 2.92) heads than\nin fresh (66.93 Ã?± 1.10) or fixated (70.77 Ã?± 1.32) heads (both P < 0.001). The ISQ score (fresh) was significantly higher for those\nin OA (73.52 Ã?± 1.92) versus OP (67.13 Ã?± 1.09) heads. However, mixed linear analysis showed no significant association between\nISQ scores and morphologic or histomorphometric results (P > 0.5 in all cases), and no significant differences in ISQ values were\nfound as a function of the length or area of the cortical layer (both ???? > 0.08). Conclusion. Although RFA-determined ISQ values\nare not correlated withmorphometric parameters, they can discriminate bone quality (OP versus OA). This ex vivo model is useful\nfor dental implant studies.
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