Maintaining sharp periodontal instruments is critical for effective scaling and root planing, yet little data exist on how different sharpening methods affect instrument and root surface roughness. This in-vitro study examined the effects of various manual sharpening diamond- coated cards (medium, fine, extra-fine) and synthetic stones (medium India, fine ceramic) on the roughness of Gracey 11/12 curette edges and instrumented root surfaces. All instruments were sharpened by a single operator using a standardized stationary instrument, moving stone (SIMS) technique. Root planing was then performed on mounted extracted teeth. Using optical profilometry, surface roughness was quantified. Results showed that fine grit abrasives produced smoother cutting edges and root surfaces compared to coarse grit abrasives (p < 0.05). Curettes sharpened with the extra-fine diamond card yielded the lowest roughness on both the instrument edge and the root surface. The orientation of the sharpening card influenced outcomes with a vertical orientation resulting in a significantly smoother edge than a horizontal orientation. Sequential sharpening, using fine then extra fine cards, further reduced edge and root roughness compared with using only a single fine grit. These findings highlight the importance of using extra-fine grit sharpening tools and proper sharpening technique to produce a smooth root surface.
