Absorption capability of knitted and braided retraction cords

Objectives:  To evaluate the absorption ability of 4 different retraction cords of varied thickness when submerged to hemostatic solution. Methods: Ultrapak  Knitted (No. 00 and No. 2 - Ultradent) and First String Braided (XS and L – Clinician's Choice)  retraction  cords with identical lengths (40 mm) were used. The capability of the cords to absorb hemostatic agent (Hemodent - Premier) was measured by a gravimetric method. The cords were soaked for three time intervals (1, 5 and 20 minutes) in the hemostatic solution at room temperature and left undisturbed. For each of the groups, 15 pieces of cord were tested. The liquid absorbance was assessed by determining the equivalent percentage of grams of fluid absorbed by grams of dry cord (%). Before the cord was weighed by an electronic analytical balance ( AB-54-5; Mettler-Toledo AG), excess fluid accumulated on cord was removed by compressing the cord between two gauzes with a 300g-weight device. Results: The data were analyzed using 1-way ANOVA for each time interval and Fisher's PLSD test at a=0.05 and are summarized in this table:

Time interval	First String XS	Ultrapak 00	First String L	Ultrapak 2
1 minute	99%B	58% C	120% A	17% D
5 minutes	77% b	29% c	129% a	11% d
20 minutes	89% B	44% C	123% A	9% D

Conclusions: Independently of the soaking time and cord thickness, the braided cords (First String -  Clinician's Choice) absorbed significantly more hemostatic solution when compared to the knitted cords (Ultrapak - Ultradent ).