Method: HAp particles calcinated at 1200 °C, with an average size of 3.18 µm, were used. The HAp particles were accelerated and blasted from the nozzle onto the enamel substrate at room temperature and atmospheric pressure. The accelerating pressure was 0.5 MPa, and the feed pressure was 0.4 MPa. The nozzle was manually scanned at a speed of approximately 10 mm/sec. HAp films with an area of 2 mm x 2 mm were prepared. The HAp film was polished by a diamond polishing paste, DiaPolisher Paste (GC Corporation, Tokyo, Japan) using a felt wheel for 30 sec. The HAp film was evaluated on 3-dimensional view, surface roughness, gloss, and SEM images before and after polishing.
Result: The HAp particles in the deposited film were densely packed. The maximum film thickness was more than 60 µm, and the average film thickness was about 50 µm. The surface roughness of the polished HAp film was significantly lower than that of the raw HAp film (P < 0.05). The gloss of the polished HAp film was significantly higher than that of the raw HAp film (P < 0.05). SEM images showed that the HAp film obtained a smooth surface by polishing.
Conclusion: Compared with previous reports, a thicker HAp film was created on the enamel substrate by the developed PJD technique. The smoothness and high gloss of the HAp film can be obtained by polishing.