Evaluation of the dentin remaining after flaring using Gates Glidden drills and Protaper rotary files

Resumo

Introduction: The application of rotary instruments for root canal
preparation requires a safe, not harming procedure to the root
structure remaining. Objective: The purpose of this study was to
analyze the root thickness in 28 mesial canals of lower permanent
first molars before and after flaring using two rotary instruments:
Gates-Glidden drills and ProTaper rotary files. Material and methods:
Teeth were embedded into a muffle system. Samples were obtained
by cutting 2mm below the furcation. The images were captured
by a digital video system (8X and 12X magnification). For image
analysis and processing, Pro-Image Plus 4.1 software was used.
Each image captured by the computer was gauged, eliminating any
possible distortion. Gates-Glidden drills were used in decreasing
order of size (GG#4, GG#3, GG#2). ProTaper was used according
to the manufacturer’s recommendations, with hand-piece powered
by an electric motor with low torque. 5.25% sodium hypochlorite
was utilized as irrigant. Results: The average thickness between
the canal and furcation before and after use of rotary instruments
were: 0.857 mm and 0.561 mm for Gates-Glidden drills, and 0.858 mm and 0.486 mm for ProTaper, respectively. No statistical
differences were found in the root thickness of specimens shaped
with ProTaper rotary files and Gates Glidden drills. Conclusion:
The use of Gates-Glidden drills is as safe as ProTaper rotary files
with respect to danger of perforation on the distal side of the mesial
roots of lower molars.