Penetration Depths and Volumes of Different Retraction Pastes

Objectives: To measure the depth of gingival penetration and volume of material for four retraction pastes and the depth of penetration for two different-sized retraction cords.

Methods: In a polystyrene mold(30mmX30mmX12mm), Post-It" Index Notes(3M) were used as place-holders to create a simulated gingival sulcus 8mm-deep with widths of 0.06mm, 0.13mm, and 0.19mm. The mold was filled with Permadyne(3M ESPE) hand-mix polyether impression material to simulate the gingiva. After setting, the elastomeric block was removed from the mold, the upper-edge cut at 45°, replaced in the mold and mass measured. Four retraction pastes Retraction Capsule (RC,3M ESPE), Expasyl (EX,Acteon Pharma), GingiTrac Minimix (GT,Centrix), and Traxodent(TR,Premier) were added to the sulci according to manufacturer's instructions and weighed after each insertion. Two retraction cords Ultrapak#3 (Ultradent) and Ultrapak#000 (Ultradent) were placed as controls. Depth measurements were taken. Each material was measured 8-times at each sulcus-width. Data was analyzed using One-Way-ANOVA and Tukey's-Test with Minitab15.

Results:

		Material
	Sulcus-Width	RC	EX	GT	TR
Depth(mm)	0.06	6.13±0.612	4.75±0.935	5.81±0.961	3.56±0.438
	0.13	6.66±0.442	5.38±0.655	6.47±0.700	4.38±0.582
	0.19	7.06±0.530	6.16±0.566	7.56±0.438	4.63±0.354
Volume(mm3)	0.06	0.0626±0.0141	0.0472±0.0125	0.0245±0.0089	0.0168±0.0030
	0.13	0.0803±0.0164	0.0596±0.0191	0.0324±0.0126	0.0223±0.0077
	0.19	0.0840±0.0144	0.0767±0.0219	0.0450±0.0101	0.0252±0.0066

 

Conclusions: At each sulcus-width, RC and GT were inserted to similar depths, while EX had a significantly shallower depth. TR showed the shallowest depth (p<0.05). At sulcus-widths of 0.06mm and 0.13mm, volume of RC was significantly greater than the other pastes, while EX had greater volume than GT and TR (p<0.05). At 0.19mm sulcus-width, similar volumes of RC and EX were observed, while there was significantly less volume of GT. TR had a volume lower than all other pastes (p<0.05). This data may have clinical relevance in selecting an appropriate paste for gingival retraction based on desired depth and width of retraction.