Histomorphometric evaluation of the thin hydroxyapatite layer formed through anodization followed by hydrothermal treatment

Abstract

By the previously described method of electrochemical and hydrothermal reaction, a thin hydroxyapatite (HA) layer of 1 microm thickness was formed on machined, grit-blasted, and titanium plasma-sprayed implants, the surfaces of which were equipped with a gap zone of 0.15 mm in depth. These implants, together with HA and titanium plasma-sprayed implants as control materials, were placed in dog mandibles for 4 weeks. Histomorphometrical comparison was performed to examine the effects of the thin HA layer and the surface topography on bone formation. The roughened implants, especially the grit-blasted implants, were surrounded with thin bone newly formed along the rough surfaces and showed higher bone apposition than the smooth implants. The gap zone of the HA plasma-sprayed implant was repaired with new bone that had vertically extended from the surrounding bone. The thin HA layer had as much osteoconduction as a plasma-sprayed HA coating but showed significantly different bone response. The results suggest that bone formation on an HA film is affected by degradation in living tissue that is related to the crystallinity and the chemical composition of the HA film itself.

Improved biological performance of Ti implants due to surface modification by micro-arc oxidation

“…Another advantage of this MAO process is the possibility of incorporating Ca and P ions into the surface layer, by controlling the composition and concentration of the electrolyte [9,10]. The incorporated Ca and P ions were even crystallized into hydroxyapatite or other calcium phosphates by a hydrothermal treatment [10,11]. Recent studies on the biological response of Ti implants demonstrated that the MAO process constitutes one of the best methods of modifying the implant surface [12][13][14][15][16][17].…”

Effect of frequency on the structure and cell response of Ca- and P-containing MAO films

“…One of the advantages of MAO process is the possibility of incorporating Ca and P ions into the surface layer, by controlling the composition and concentration of the electrolyte [16]. The incorporated Ca and P ions can further crystallize into hydroxyapatite or other calcium phosphate minerals by hydrothermal treatment [17,18].…”

Primary Osteintegration in the Study of Biomimetic Surfaces

“…The excellent results obtained by the osteoconductive coatings in terms of osteoinegration capacity led to the study and the development of alternative methods of coating. An anodizing technique, known as Anodic Spark Deposition or Anodic Spark Discharge (ASD) has been considered, as a starting point for the development of treatments designed to improve osteointegration (Ishizawa, 1995a(Ishizawa, , 1995b(Ishizawa, , 1997. With this technique it is possible to obtain porous surfaces rich in oxygen, with a relatively thick oxide layer, enriched with electrolytes dissolved in the medium during the anodic deposition process (Schreckenbach, 1999).…”