In Vitro Evaluation of Apical Transportation Induced by Single- and Dual-Thermally Treated NiTi Instruments

Area of Science:

• Endodontics
• Dental Materials Science
• Biomaterials Engineering

Background:

• Martensitic endodontic instruments offer superior flexibility, reducing apical transportation versus austenitic instruments.
• Newer instruments with dual thermal treatment aim for enhanced tip cutting and body flexibility.
• Concerns exist that increased tip stiffness may elevate apical transportation.

Purpose of the Study:

• To compare apical transportation between SlimShaper (single thermal treatment) and SlimShaper PRO (dual thermal treatment) nickel-titanium (NiTi) instruments.
• To assess the impact of dual thermal treatment on NiTi endodontic instrument performance regarding apical transportation.

Main Methods:

• Forty-four standardized J-shaped resin blocks were used, divided into two groups (n=22).
• Group A utilized SlimShaper, and Group B used SlimShaper PRO, both up to size 25/0.04.
• Apical transportation was evaluated by superimposing pre- and post-shaping photographs; statistical analysis employed the independent Student's t-test (p < 0.05).

Main Results:

• Mean apical transportation for SlimShaper was 0.08423 mm (SD 0.01049).
• Mean apical transportation for SlimShaper PRO was 0.08609 mm (SD 0.01102).
• No statistically significant difference in apical transportation was found between the two groups (p = 0.57).

Conclusions:

• Dual-thermally treated SlimShaper PRO instruments did not result in greater apical transportation than single-thermally treated SlimShaper instruments.
• The findings suggest that dual thermal treatment, under the study conditions, does not adversely affect apical transportation in NiTi endodontic instruments.