# Gracey’s curette no 15/16 is used for:
A. Anterior teeth
B. Premolars
C. Mesial surface of posterior teeth
D. Distal surface of posterior teeth
The correct answer is C. Mesial surface of posterior teeth.
Double-ended Gracey curettes are paired in the following manner:
Gracey #1-2 and 3-4: Anterior teeth
Gracey #5-6: Anterior teeth and premolars
Gracey #7-8 and 9-10: Posterior teeth: facial and lingual
Gracey #11-12: Posterior teeth: mesial
Gracey #13-14: Posterior teeth: distal
Recent additions to the Gracey curette set have been the Gracey #15-16 and 17-18. The Gracey #15-16 is a modification of the standard #11-12 and is designed for the mesial surfaces of posterior teeth. It consists of a Gracey #11-12 blade combined with the more acutely angled #13-14 shank. When the clinician is using an intraoral finger rest, it is often difficult to position the lower shank of the Gracey #11-12 so that it is parallel with the mesial surfaces of the posterior teeth, especially on the mandibular molars. The new shank angulation of the Gracey #15-16 allows better adaptation to posterior mesial surfaces from a front position with intraoral rests. If alternative fulcrums, such as extraoral or opposite-arch rests, are used, the Gracey #11-12 works well and the new #15-16 is not essential.