Relationship of syringe-tip diameter to voids in elastomer impressions

An in vitro study was done to determine the relationship between syringe-tip diameters and the number of bubbles in extruded strips of two vinyl silicone impression materials. Results disclosed the following. There were highly significantly fewer bubbles in impression material extrusions from the second half of the syringeful than from the first half (p less than .001). The smaller-tip orifices, 0.6 and 0.67 mm in diameter, caused highly significantly fewer bubbles in the extruded impression materials than did the larger tips (p less than .001). The reasons and clinical implications for these effects are unknown and are being explored. From subjective observations, it was concluded that the pneumatically powered syringe provided an easier means of extruding the impression material through small syringe-tip orifices than did the conventional hand-powered syringe.