Comparison of early osseointegration of SLA^® and SLActive^® implants in maxillary sinus augmentation: a pilot study

To assess the impact of a hydrophilic implant surface (SLActive^® ) placed into augmented maxillary sinuses on bone-to-implant contact (BIC) and surrounding tissue composition when compared to a hydrophobic surface (SLA^® ).

Four sheep underwent bilateral sinus augmentation. Each sinus received anorganic bovine bone mineral + autogenous bone (ABBM + AB). Sixteen implants were subsequently placed 12 weeks postgrafting with each sinus receiving a control (SLA^® ) and test implant (SLActive^® ). Two animals were sacrificed at 2 weeks and another two animals were sacrificed at 4 weeks postimplantation. The eight sinuses and 16 implants were processed for histomorphometry, which assessed bone-to-implant contact (%BIC) and tissue elements (woven bone - WB, lamellar bone - LB, soft tissue - ST) in the interthread region of implants within the augmented sinus.

There was a statistically significant increase in %BIC at week 4 compared to the week 2 animals in both test (P < 0.005) and control (P < 0.005) groups. There was a statistically significant greater %BIC around test implants when compared to control implants in both week 2 (P < 0.05) and week 4 animals (P < 0.05). Greater %WB (11.17% ±6.82) and %LB (11.06% ±3.67) were seen in the test implants when compared to the control implants independent of time. This was only statistically significant for %LB (P < 0.05). A statistically significant reduction of 16.78% (±6.19) in %ST was noted in test implants when compared to control implants (P < 0.05) independent of time.

Both time and the use of hydrophilic implant surface had a positive impact on %BIC around implants placed into augmented maxillary sinuses. Hydrophilic implant surfaces also had a positive impact on surrounding tissue composition. Larger trials are needed to better assess and detect differences between these two surfaces in augmented maxillary sinuses.