Comparison of the scaling time between the two groups

Herein, areas of calculus measuring approximately 4 × 3 mm on the root surface (n = 15, each group), located less than 1 mm from the cementoenamel junction (CEJ), were marked using diamond burs. The teeth were scaled similarly to their clinical application, with the working tip held at an angle of approximately 10° in the marked area and moved in a zigzag manner from the top to the bottom of the root (Fig. 2). The surface of interest was cleaned and smoothed by overlapping each movement until it met the visual and tactile criteria, as determined by a sharp explorer. The time taken to manipulate each surface to meet the above criteria was recorded. Throughout the study, the roots were held in a saline solution to prevent desiccation.

Schematic diagram of tooth preparation for the in vitro tooth experiment. (A) Area of 3 × 4 mm marked under the CEJ for subgingival scaling. (B) Working tip moving in the 'z' direction.