Our local hygiene schools do not include Gracey 11/12 and 13/14 in their instruments for the students. In lieu of this they substitute the Gracey 15/16 and the Gracey 17/18. I was not aware that they were supposed to be thought of as superior to the usual, but that they were supplemental to the recommended basic setup. Your comment?
Both the 15/16 and 17/18 were designed to improve access to the areas in which they are used. They provide the perfect complimentary pair of scaling instruments to access difficult to reach areas. The 15/16 permits easier adaption with an intra-oral fulcrum when adapting to the mesial surfaces of maxillary and mandibular molars. The increased angle of the shank allows for an intra-oral fulcrum when instrumenting maxillary molars and creates a more parallel shank to tooth position in mandibular molars. Likewise, the 17/18 provides easier adaption to distal surfaces of maxillary and mandibular molars. The multiple bends improve handle positioning and provide crown clearance when instrumenting the distal surfaces of second and third molars. I personally think it is a matter of preference and what works best in a learning institution. In our program, we find students struggle less adapting the 15/16, yet have no struggles with the 13/14. Our Gracey set is the 1/2, 13/14 and 15/16. However, our mini set of Graceys includes the 1/2, 11/12 and 13/14. Most important, we make sure the students are aware of the entire set of Graceys, consisting of nine instruments, not including the 11/14 and the 12/13.