The invention concerns an injection implant for filling up wrinkles, thin lines, skin cracks and scars, for reparative or plastic surgery, aesthetic dermatology, and for filling up gums in dental treatment. The invention concerns the use of biologically absorbable polymer microspheres or microparticles suspended in a gel. Said suspension is produced either ready-for-use or freeze-dried. The biological absorbability of the microspheres is controlled and enables the production of implants having well defined persistence and deliberately limited to 3 years.