B

Refrigerant cold testing (Endo-Ice; 1,1,1,2-tetrafluoroethane) is most effectively delivered by spraying it onto a #2 cotton pellet; studies show the largest intrapulpal temperature drop when this “large” (#2) pellet is used compared with #4, cotton-tip applicators or cotton rolls [Jones, 1999, PMID 10687531; Garza, 2010, PMID 20478789].