impact of glide path preparation and instrument motion on dentinal crack formation after root canal preparation

Objective: this study investigated the effect of glide path preparation and different instruments in creating dentinal cracks during root canal instrumentation.methods: eighty maxillary molars were divided into four groups (n=20). the mesiobuccal root canals were prepared using two rotary systems (group 1: hyflex edm and group 2: protaper gold) and two reciprocating systems (group 3: waveone gold and group 4: reciproc blue r25). in each group, ten specimens were prepared using the designated glide path files. methylene blue dye was injected into the root canals to highlight dentinal cracks. the samples were then sectioned and examined under a microscope to count the number of dentinal cracks at the apical, middle, and coronal thirds. the data were analyzed using the kruskal-wallis and mann-whitney u tests (p<0.05).results: when glide path files were not used, the number of cracks was comparable across the groups in coronal, middle and apical sections (p>0.05). among the samples prepared with glide path files, those instrumented with waveone gold showed a significantly higher number of dentinal cracks in the coronal section compared to protaper gold (p<0.05), and in the middle section compared to both hyflex edm and protaper gold (p<0.05). in the apical section, no significant difference in the number of cracks was observed among the groups (p=0.627).conclusions: glide path preparation with rotary systems (protaper gold and hyflex edm) resulted in fewer dentinal cracks in the mesiobuccal root canals of maxillary molars compared to a reciprocating system (waveone gold).