Methodological assessments of subcutaneous implantation techniques.

Results from 197 subcutaneous implants on rats and 40 on mice of three different dental biomaterials were studied with emphasis on methodological evaluations. The types of implants employed allowed a differentiation between the materials based on the tissue reactions induced, but the degree of response recorded depended on the technique and the animal employed. The main problems encountered were the effect of operative trauma in short-term experiments, loss of material/tissue interface, dislodgement of tearing of sections if the materials remained in situ, folding and distortion of tissue, and difficulties in orientation of specimens for sectioning. The tube implant supplied with a window and sectioned perpendicularly on the long axis of the tube gave the least methodological problems. This "window technique" is therefore recommended as the method of choice for subcutaneous implantations. Cell density evaluations allowed quantitative determinations of the cellular response.