In Vitro Analysis of Bone Response to Different Implant Surface Roughness

The surface roughness of dental implants plays a critical role in osseointegration by enhancing bone-implant contact. However, the optimal surface topography to maximize bone response is still under investigation.

Titanium implants with three different surface roughness categories were tested: smooth (Ra = 0.5 μm), moderately rough (Ra = 1.5 μm), and rough (Ra = 3.0 μm). The samples were incubated with osteoblast-like cells (MG-63) for 14 and 28 days. Alkaline phosphatase (ALP) activity, cell viability (MTT assay), and mineralization (Alizarin Red staining) were assessed to quantify the bone response. Scanning Electron Microscopy (SEM) was performed to examine cell morphology on the implant surfaces.

At 14 days, ALP activity was significantly higher on moderately rough surfaces (30.5 ± 1.2 U/L) compared to smooth (18.2 U/L ±0.8 U/L) and rough surfaces (22.6 U/L ±1.0 U/L). The MTT assay showed improved cell proliferation on moderately rough surfaces (optical density 0.85 ± 0.03) compared to smooth (0.56 ± 0.02) and rough surfaces (0.61 ± 0.04). Mineralization at 28 days was most prominent on moderately rough surfaces, with Alizarin Red absorbance of 0.95 ± 0.02, followed by rough (0.75 ± 0.03) and smooth (0.40 ± 0.02). SEM analysis revealed well-spread cell morphology on both moderately rough and rough surfaces.

Moderately rough implant surfaces exhibited superior bone response compared to smooth and rough surfaces, highlighting the importance of controlled surface topography in enhancing osseointegration. Future studies should explore the molecular mechanisms underlying these differences to optimize implant design further.