Plasma spraying is a technique currently used in the production of HA-coated titanium implants. These coatings have been shown to be porous; they dissolve and have a weak bond to the substrate.

The purpose of the investigation was to study the bond strength between silanized titanium specimens and poly(methyl methacrylate) (PMMA).
The average bond strength of the specimens after dry storage at 37°C was 25 MPa. Water storage for 30, 60 or 90 days at 37°C reduced the bond strength to approximately 9–11 MPa.