Evaluation of three different manual techniques of sharpening curettes through a scanning electron microscope: a randomized controlled experimental study.

OBJECTIVE: The purpose of this study was to compare the effectiveness of three different techniques for manually sharpening of periodontal curettes (PCs) by examining the blades with the aid of scanning electron microscope (SEM). METHODS: Three groups were considered based on three sharpening methods used: group A (moving a PC over a stationary stone); group B (moving a stone over a stationary PC) and group C (moving a PC over a stone fixed, placed on a 'sharpening horse'). After the sharpening, the blades were examined using SEM. The SEM images were assessed independently by five different independent observers. An evaluation board was used to assign a value to each image. A preliminary pilot study was conducted to establish the number of samples. Pearson's correlation test was used to assess the correlations between measurements. anova test with Bonferroni's post hoc test was used to compare the three groups. RESULTS: Sixty PCs (20 PCs per group) were used in this study. Statistically significant differences emerged between the three groups (P-value = 0.001). Bonferroni's test showed that the difference between groups A and B was not statistically significant (P-value = 0.80), while it was significant for the comparisons between groups A and C (P-value = 0.005) and between groups B and C (P-value = 0.001). CONCLUSIONS: The sharpening technique used in group C, which involved the use of the sharpening horse, proved the most effective.