[Residual dentin thickness in first premolars after root canal preparation]

Area of Science:

• Endodontics
• Restorative Dentistry
• Dental Materials Science

Background:

• Post preparation is essential for restoring endodontically treated teeth.
• Inadequate residual dentin thickness (RDT) can compromise root strength and lead to fractures.
• Selecting appropriate peeso drill sizes is critical to avoid over-preparation and maintain structural integrity.

Purpose of the Study:

• To anatomically measure residual dentin thickness (RDT) in first premolars before and after post preparation.
• To provide data-driven guidance for clinicians on selecting optimal peeso drill sizes.
• To evaluate the impact of different peeso drill sizes on RDT in maxillary and mandibular premolars.

Main Methods:

• Thirty maxillary and thirty mandibular first premolars were collected.
• Residual dentin thickness was measured 4 mm from the apex before and after preparation with peeso drills (sizes 1-3).
• Statistical analysis was performed to compare RDT measurements.

Main Results:

• For two-canal maxillary and single-canal mandibular premolars, RDT was less than 1 mm after using peeso drill size 3.
• Significant differences in RDT were observed in the palatine root of maxillary premolars and in mandibular premolars (P<0.05).
• For single-canal maxillary premolars, RDT was less than 1 mm after using peeso drill size 2, with significant differences in the distal wall (P<0.05).

Conclusions:

• For the buccal root of two-canal maxillary premolars, the maximum recommended peeso drill size is 3.
• For the palatine root of maxillary premolars and for mandibular premolars, the maximum recommended peeso drill size is 2.
• For single-canal maxillary premolars, the maximum recommended peeso drill size is 1.