Review of tissue retraction systems for impressions in restorative dentistry [Revisione dei sistemi di retrazione gengivale a fini protesici]

OBJECTIVES. This paper shows the most common tissue retraction systems for impressions in restorative dentistry. The purpose of this literature review is to give specific indications for any retraction system and to discuss their contraindications. The authors examined both mechanical and surgical retraction systems. The first comprise copper band technique, impression matrix technique and specific volumetric expansion materials; combinations of mechanical and chemical technique are also showed. RESULTS AND CONCLUSIONS. The authors focused on the double cord impression technique and its combination with haemostatic fluids.This technique has few contraindications, however it is more time-consuming for the dentist. Care must be taken in the use of haemostatic fluids because of their possible side effects, especially for epinephrine. Retraction systems are strictly operator-dependent and their results depend also on patient periodontal state.