Comparative study of the efficacy of two newly introduced rotary nickel titanium instruments in shaping of curved root canals

الملخص EN

The present study compared the efficacy of two newly introduced rotary Ni-Ti instruments, HeroShaper and NRT in preparation of curved canals.

A total of sixty mesiobuccal root canals of human mandibular molars were equally divided into the two experimental groups.

Crown-down technique was used with applying manufacturer instructions.

Each instrument prepared ten canals.

Irrigation was done using normal saline and commercially available soap was used for lubrication.

Pre- and postoperative radiographs were taken, and then digitally processed.

Shaping ability was assessed by measuring the change in canal curvature.

Centering ability was determined by measuring the change in dentin thickness at five fixed levels, change in working length was evaluated by technical measurement pre- and postoperatively and durability was recorded by inspection of files after each use for any sign of permanent deformation or instrument separation.

Both rotary systems achieved good results regarding the assessed criteria with no significant difference; however HeroShaper saved more dentin especially in the mid-root area.

Inspection of the used HeroShaper and NRT instruments showed some incidence of overtwisting, unwinding and separation It was concluded that both Ni-Ti rotary systems were efficient in shaping curved root canals regarding maintaining canal curvature, position of angle of curvature, working length and canal centering.

The usage of digital radiographic technique in assessment of shaping ability was an effective technique.