In vitro changes of hydroxyapatite coatings.
The stability and degradability of hydroxyapatite coatings on dental implants depends on the dissolution of the individual chemical phases. Hydroxyapatite-coated dental implants exhibit a range of amorphous-phase content. Two tests were conducted to observe the course of coating degradation. The first test showed degradation of both crystalline and amorphous coatings by cracking and dissolution after immersion in Ringer's solution. Concomitant saturation of the implants in the solution modified the coated surface with precipitated crystalline apatite. A second test, intended to replicate the conditions of infection by decreasing pH, illustrated preferred dissolution of the amorphous phase, liberating crystalline segments. It is expected that morphologic changes could influence the rate of bone bonding and therefore could alter or control implant-tissue interactions.
Gross
K A
KA
Department of Materials Science, University of Technology, Sydney, Australia. Karlis.Gross@uts.edu.au
Berndt
C C
CC
Goldschlag
D D
DD
Iacono
V J
VJ
D001031:Apatites / Q000737:chemistry; D001424:Bacterial Infections / Q000378:metabolism; D001672:Biocompatible Materials / Q000032:analysis / Q000737:chemistry*; D002130:Calcium Phosphates / Q000032:analysis / Q000737:chemistry; D055598:Chemical Phenomena; D011232:Chemical Precipitation; D002627:Chemistry, Physical; D019343:Citric Acid / Q000737:chemistry; D003460:Crystallization; D015921:Dental Implants; D017886:Durapatite / Q000032:analysis / Q000737:chemistry*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007101:Immersion; D007552:Isotonic Solutions / Q000737:chemistry; D008422:Materials Testing; D016348:Osseointegration; D016062:Porosity; D000077331:Ringer's Solution; D012995:Solubility; D013499:Surface Properties; D014961:X-Ray Diffraction
D001031:Apatites; D001672:Biocompatible Materials; D002130:Calcium Phosphates; D015921:Dental Implants; D007552:Isotonic Solutions; D019343:Citric Acid; D000077331:Ringer's Solution; D017886:Durapatite