A machined implant is blasted with a material that can then be removed by washing the implant in a specific solvent. This will create an irregular, roughened surface that might be more conducive to osseointegration. Grit blasting may be combined with chemical etching.

Again, an increase in surface roughness may promote ossteoblastic activity and get a faster/stronger level of osseointegration. To date, there is no proof of this.

None, except for the possibility of contamination which I have not seen....

Acceptable provided contaminants have been totally removed from the surface.