At least one embodiment of a method for dynamically assisting a practitioner in preparing a dental bone grafting operation, the method comprising:—providing an image representing a 3D volume of a portion of a jaw member where bone grafting is to be carried out;—adding to the image a representation of a 3D virtual object representing dental bone graft material;—estimating a value of a geometric characteristic relating to the bone graft material to be used, as a function of geometric characteristics of the represented 3D virtual object;—enabling a user to modify the representation of the 3D virtual object; and—upon modification of the representation of the 3D virtual object, updating the estimated value of the geometric characteristic, according to the modification of the representation of the 3D virtual object, the estimated value assisting the practitioner in determining the dental bone graft material needed.