THE EFFECT OF DISPLACEMENT TIME ON GINGIVAL CREVICE WIDTH

The authors investigated the length of time medicated displacement cor d should remain in the gingival crevice prior to impression making. A silk cord (Deknatel) was placed into the sulcus and was not removed du ring the study. Medicated cords (Hemodent on Ultrapak #1) were placed into the gingival sulcus for 2, 4, 6, and 8 minutes. Following cord re moval, closure of the sulcus was recorded at intervals using a miniatu re video camera. Crevicular widths were measured at the midbuccal and transitional line angle areas. At both the midbuccal and transitional line angle areas, gingival crevices displaced for 2 minutes were signi ficantly smaller at 20 seconds (P<.05) than crevices following displac ement for 4, 6, and 8 minutes. No significant difference in crevicular width was found at any time period after cord removal for crevices di splaced for 4, 6, and 8 minutes. At the transitional line angle, crevi cular widths were significantly smaller than al the midbuccal at 20 se conds for all times and remained so up to 180 seconds. To achieve a cr evicular width of 0.2 mm, cord should remain in the gingival crevice f or an optimum time of 4 minutes prior to impression making when using the materials evaluated in this study.