Abstract
BACKGROUND AND OBJECTIVES: The aim of this study was to see the incidence of cracks in root dentin after coronal flaring using various rotary instruments such as Gates Glidden (GG) drills, ProTaper Universal SX, OneFlare, and HyFlex EDM. MATERIALS AND METHODS: Seventy freshly extracted premolar teeth with single canal were collected. All the teeth were randomly divided into five groups of fourteen each (n = 14), of which one group served as the control and the rest of the four groups were instrumented with GG drills, ProTaper Universal SX, OneFlare, and HyFlex EDM, respectively. RESULTS: The GG drills resulted in a higher rate of crack formation in root dentin (P < 0.05) than the ProTaper Universal SX, OneFlare, and HyFlex EDM instruments (P > 0.05). CONCLUSION: The use of GG drills resulted in more crack formation. However, the results for the ProTaper Universal SX, OneFlare, and HyFlex EDM flaring instruments were less in terms of crack formation.