Endodontic Instruments and Techniques

Introduction to Endodontic Instruments

• Instruments play a crucial role in the success of a root canal treatment.
• A basic knowledge of endodontic instruments is essential due to the complex and varied canal anatomy.

Classification of Endodontic Instruments

• According to Grossman, endodontic instruments can be classified into four categories:
  • Exploring instruments: to locate the canal orifice and determine patency of the root canal (e.g., endodontic explorers, smooth broaches).
  • Debriding instruments: to extirpate the pulp and remove any foreign debris (e.g., barbed broach).
  • Cleaning and shaping instruments: to clean and shape the root canal laterally and apically (e.g., reamers and files).
  • Obturating instruments: to cement and pack gutta-percha into the root (e.g., spreaders, pluggers, and lentulospirals).

Classification of Cleaning and Shaping Instruments

• According to ISO-FDI, cleaning and shaping instruments can be classified into groups based on use:
  • Group I: Hand Use only (e.g., H-file, NiTi instruments).
  • Group VI: Sonic and UltraSonic Instruments.

Design of Endodontic Instruments

• Components of a file:
  • Taper
  • Core
  • Flute
  • Cutting edge
  • Land
  • Helix angle
  • Pitch
  • Rake angle
  • Cutting angle
  • Tip design
• Taper is expressed as the amount of file diameter increases each millimeter along its working surface from the tip towards the file handle.
• Examples of instrument taper profiles:
  • HERO 642: 2%, 4%, 6%
  • K3: 2%, 4%, 6%
  • FLEXMASTER: 2%, 4%, 6%, INTRO FILE-11%

Standardization of Endodontic Instruments

• ISO-color coding: with the exception of Pink, Gray, and Purple, all the colors are repeated every six instruments.
• Ingle's Original Recommendation:
  • Cutting blades 16 mm in length
  • 2% or 0.02 Taper
  • Diameter of the instrument at tip (D1) is determined by size in hundredths of millimeters
  • Diameter 2 (D2) is uniformly 0.32 mm greater than D1
  • Length: 21, 25, 31 mm
  • Specification for shapes of the tip: 75 degrees, ± 15 degrees

Clinical Classification

• Instruments used for diagnosis:
  • Endodontic explorers
  • Tooth Slooth
  • Dental Transilluminator
  • Pulp Vitality Tester
• Instruments used for access opening:
  • Round diamond bur
  • Taper diamond flat end bur
  • Fissure Carbide Bur
  • Safe End Long Bur
  • Endo Z Bur
• Instruments used for canal preparation:
  • Instruments used to remove pulp tissue:
    • Barbed broaches
    • Endodontic excavators
  • Reamers and files