For this were used Periopaper® absorbent paper strips (OraFlow Inc., New York, NY, USA). The teeth were isolated from a relative fashion using cotton rolls, once isolated with a Gracey 3/4 the supra-gingival plaque be removed and gently the surface of the triple air dry syringe. The paper strip was introduced into the selected tooth gingival sulcus until mild resistance tissue and held for 30 seconds. Then they were placed in properly labeled Eppendorf tubes and transported immediately to be stored at -80 ° C until the centrifugal elution process. The paper strips contaminated with saliva or blood were discarded.