The minimum residual root thickness after using ProTaper, RaCe and Gates-Glidden drills: A cone beam computerized...

Area of Science:

• Endodontics
• Dental Anatomy
• Radiology

Background:

• Coronal preflaring is crucial for root canal preparation.
• The mesio-buccal (MB) canal in mandibular molars presents unique anatomical challenges.
• Ensuring adequate root thickness in the danger zone is vital to prevent perforation.

Purpose of the Study:

• To evaluate the minimum residual root thickness (MRRT) in the danger zone of mandibular first molar MB canals.
• To compare the effects of ProTaper, RaCe, and Gates-Glidden (GG) drills as coronal shapers on MRRT using cone-beam computed tomography (CBCT).

Main Methods:

• CBCT scans were used to assess MRRT in 75 MB canals at 1, 2, 3, and 4 mm from the furcation.
• Samples were divided into three groups: ProTaper, RaCe, and GG drills.
• Canals were instrumented to a master apical file (MAF) of #25, with coronal shaping performed by the respective instruments.

Main Results:

• Gates-Glidden drills removed significantly more dentin than RaCe and ProTaper at specific sections.
• No statistically significant difference in MRRT was found between the ProTaper, RaCe, and GG groups.
• The mean MRRT remained above 0.75 mm in all sections across all tested groups.

Conclusions:

• ProTaper, RaCe, and Gates-Glidden drills can be safely employed as coronal shapers in MB canals of mandibular first molars.
• The choice of instrument for coronal shaping does not compromise the minimum residual root thickness when initial root thickness is adequate.
• These findings support the safe use of these instruments in endodontic procedures involving mandibular molars.