RPD Review Questions
Incorrect. Clasps originating above the height of contour are suprabulge retainers, "supra" meaning above.
Correct. "Infra" means below so infrabulge clasps originate below the height of contour and approach the undercut from a gingival direction.
Incorrect. Infrabulge clasps approach the undercut from below---from a gingival direction. Also, by definition, supra or infrabulge categories are based on a relationship to the "bulge" or height of contour, not to the amount of undercut.
Incorrect. An approach from above the occlusal surface would constitute "suprabulge". Such an approach is also impractical and nonsensical.