Pulsed laser deposition (PLD) can be used to produce calcium phosphate (CaP) coatings of uniform thickness with a controlled ratio of hydroxyapatite (HA) to other CaP phases. Objective: The aim of this study was to compare HA coatings deposited by PLD to commercially used plasma sprayed coatings as to their bond strength and dissolution properties. Methods: 36 titanium alloy discs of 7 mm diameter and 1 mm thickness were prepared, with 12 sent to be plasma sprayed (Biocoat, Southfield, MI) in a manner identical to commercial dental implants including surface roughening using aluminum oxide. 24 specimens were polished to 1000 grit SiC paper and coated using PLD with deposition parameters varied to obtain both high-crystallinity HA and low-crystallinity HA specimens. Bond strength testing of the coatings was accomplished using a Sebastian Five thin film tester. The dissolution study took place under tissue culture conditions in a simulated physiologic solution without protein (Earle?s balanced salt solution). SEM images and XRD analyses were taken at every time point (1, 3, 7, 14, 28 and 42 days) along with bond strength testing to determine loss of adhesion and/or coating thickness with time. The effects of coating method, composition and/ surface roughness on bond strength and dissolution were determined by ANOVA (p<0.05). Results: Bond strengths of the coatings were as follows [mean (SD) in MPa]: PLD-high HA coatings: 65.4 (16.7); PLD-low HA: 61.7(13.4), plasma sprayed: 44.4 (17.7). Conclusions: HA coatings deposited by PLD exhibited significantly stronger bond strength to Ti alloy than plasma sprayed coatings, but there was no significant difference between the bond strength for PLD coatings containing high HA vs. low HA. Neither bond strength nor coating thickness of any of the 3 types of coatings decreased significantly after 14 days in solution.

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