Early Bone Response to Dual Acid-Etched and Machined Dental Implants Placed in the Posterior Maxilla: A Histologic and Histomorphometric Human Study

Purpose: To compare the early bone response to implants with dual acid-etched (DAE) and machined (MA) surface, when placed in the posterior human maxilla. Materials and Methods: Fourteen patients received 2 implants in the posterior maxilla: 1 DAE and 1 MA. After 2 months, the implants were retrieved for histologic/ histomorphometric evaluation. The bone-to-implant contact (BIC%), bone density in the threaded area (BDTA %), and the bone density (BD%) were calculated. The Wilcoxon matchedpairs signed rank test was used to evaluate differences (BIC%, BDTA%, and BD%) between the surfaces. Results: In the MA implants, a mean (+/- SD) BIC%, BDTA%, and BD% of 21.76 (+/- 12.79), 28.58 (+/- 16.91), and 21.54 (+/- 11.67), respectively, was reported. In the DAE implants, a mean (+/- SD) BIC %, BDTA%, and BD% of 37.49 (+/- 29.51), 30.59 (+/- 21.78), and 31.60 (+/- 18.06), respectively, was reported. Although the mean BIC% of DAE implants value was almost double than that of MA implants, no significant differences were found between the 2 groups with regard to BIC% (P = 0.198) and with regard to BDTA% (P = 0.778) and BD% (P = 0.124). Conclusions: The DAE surface increased the periimplant endosseous healing properties in the native bone of the posterior maxilla.