2.3 Gingival crevicular fluid sample collection and elution
protocol:
Oral examination and the collection of GCF samples were performed
between 11 0/7 and 13 6/7 weeks of gestation. After a tooth was isolated
with a cotton roll, the supragingival plaque was removed with curettes
but without contacting the gingival margin. The gingival sulcus was then
gently dried with an air syringe. GCF was collected using paper strips.
The strips were placed into the sulci/pocket until mild resistance was
sensed and left in place for 30 seconds. Strips contaminated by saliva
or blood were excluded from the study. After GCF collection, the strips
were placed into an Eppendorf tube containing 100 μl of
phosphate-buffered saline with 0.05% (v/v) Tween-20. GCF was eluted
from the strips by centrifugation (10,000 g for 5 min). This procedure
was repeated twice. GCF samples were obtained from four periodontal
sulcus/pockets (1 x quadrant) at the most affected periodontal site,
representative of the periodontal diagnosis of the patient, and then the
strips were pooled to make one sample119.