first of all thanks everybody for your precious help
i use EDTA 0.15 M with 1.9% glutarald#233#hyde in 0.06 M cacodylate sodium buffer, after two months i put bone in nitrix acid 5 %, with 10% glutarald#233#hyde for 3 weeks
I did switch from EDTA to nitric acid to increase decalcification rate without demaging the tissu structure
Does anyone know technique to chek if decalcification is complete other than X RAy? 
In case of Nitric acid decalcification, what do you use for rinsing to eliminate acid before ethanol dry, clearing and paraffine embedding ?
thank you
Myriam