A novel quantitative method for evaluating surface roughness using dual-angle images from a field emission scanning...

Area of Science:

• Dental Materials Science
• Biomaterials Engineering
• Endodontics

Background:

• Nickel-titanium (NiTi) instruments are widely used in endodontics.
• Surface properties of NiTi instruments can change with use and sterilization.
• Understanding these changes is vital for instrument longevity and patient safety.

Purpose of the Study:

• To assess the impact of pre-clinical (ex vivo) use and autoclave sterilization on the surface roughness of reciprocating NiTi instruments.
• To quantify changes in surface roughness parameters (Sa, Sq, Sz) at the cutting edge and flute.
• To evaluate the effectiveness of a novel dual-angle field-emission scanning electron microscopy (FE-SEM) imaging technique.

Main Methods:

• A pre-clinical study design was employed with instruments serving as their own controls.
• FE-SEM was used to capture dual-angle stereo-pair micrographs.
• Mountains software analyzed 3D surface reconstructions to quantify roughness parameters (Sa, Sq, Sz).
• Statistical analysis included repeated-measures ANOVA and Friedman tests.

Main Results:

• No significant difference in surface roughness was observed at the cutting edge before and after use in the pre-clinical environment.
• A linear trend of increased Sa and Sq parameters was noted at the cutting edge after root canal instrumentation.
• A significant difference in the Sa parameter was found at the flute of the instruments post-use.
• Pre-clinical usage demonstrably increases surface roughness, especially at the cutting edge.

Conclusions:

• Pre-clinical usage of reciprocating NiTi instruments leads to measurable increases in surface roughness.
• Surface roughness changes are more pronounced at the cutting edge.
• Regular monitoring of NiTi instrument wear is essential for maintaining performance and ensuring safety during endodontic treatments.