KINETIC-STUDY OF RELEASE OF SILICON-COMPOUNDS FROM POLYSILOXANE TISSUE EXPANDERS

The release behavior of typical commercial tissue expanders has been e xamined by carrying out two kinds of experiments: 1) Determination of chemical nature and its modification after in vivo use by X-ray photoe lectron spectroscopy for chemical analysis. This study has been parall elled by scanning electron microscopy with associated energy dispersiv e X-ray analysis of surface, as well as by silicon compounds analysis of tissues around implants. 2) Kinetic examination of silicon compound s released by the biomaterial in physiologic solution at 36 +/- 0.3 de grees C. Results of these investigations have shown independently that the starting material was not a filler-free, pure polymer, but a comp osite, reinforced elastomer, with the reinforcing agent most seemingly represented by silicon dioxide. Release of latter, with a relatively fast kinetics, is compatible with data of the simulating laboratory ru ns in the physiologic solution. All these facts seem to rule out any h ypothesis of a prevailing siloxane oligomer migration. The correlation of kinetic and physicochemical tests with the in vivo behavior is dis cussed. (C) 1995 John Wiley and Sons, Inc.