[Osteoconductive properties of bioactive glasses in a bulk form and as a coating on alumina].
BACKGROUND
Alumina on alumina friction couple has proven its reliability in the field of total hip arthroplasty. However, loosening of the alumina socket has been responsible for most of the failures. An improvement of the bone/alumina interface could be achieved with the use of an osteconductive material as a coating on alumina. The aim of this study was to evaluate the osteconductive properties of two types of bioactive glasses as a coating on alumina substrates.


METHODS
Two types of coated implants (silicate glass coated alumina - AVSi, and phosphate glass coated alumina - AVP) were evaluated in a rabbit cancellous bone model. Pure alumina implants (A) were used as negative controls and bulk glasses (silicate - VSi and original 45S5, and phosphate glasses -VP) as negative controls. Sacrifices were performed at 3, 12 and 24 weeks. The interface evaluation included histomorphometry using an image analyzer.


RESULTS
Silicate glasses demonstrated high osteoconductive properties. However, non mineralized osteoid tissue was the main tissue in contact with both coated implants and bulk phosphate glasses. This tissue covered over 70 p. 100 after 24 weeks of implantation, while it was never observed around pure alumina implants after 3 weeks.


CONCLUSIONS
Amongst the hypotheses that could explain this mineralization inhibitory process, the one involving an Al(3+) glasses contamination from Al(2) O(3) is the likeliest. The high temperature coating procedure could be responsible for alumina transformation into a more soluble phase.
Hamadouche
M
M
Laboratoire de Recherches Orthopédiques, UPRES-A-CNRS 7052, Faculté de Médecine Lariboisière-St Louis, Université Denis Diderot Paris VII, 10 avenue de Verdun, 75010 Paris, France.
Nizard
R S
RS
Meunier
A
A
Blanchat
C
C
Sedel
L
L
D000537:Aluminum Oxide; D000818:Animals; D001672:Biocompatible Materials; D018786:Bone Substitutes; D005898:Glass; D006622:Hip Prosthesis; D006801:Humans; D008422:Materials Testing; D016348:Osseointegration; D011817:Rabbits
D001672:Biocompatible Materials; D018786:Bone Substitutes; D000537:Aluminum Oxide