Apical pressures developed by needles for canal irrigation

By Bradford CE1, Eleazer PD, Downs KE, Scheetz JP

Date: 01/2002
Journal: JOE


  • Purpose: to assess the effect of Drying instrumented canals with pressurized air different needles.
  • N= G1= 10 oval canal), G2: 10 round canals. (shape classified by access)
  • Materials/Methods:

  • Instrumented with K files, after each largest size was used to ensure patancy.
  • Root end was then luted with dental wax to plastic tubing connected to a 20 to 300 mm Hg pressure gauge.
  • 5 psi applied to the test needles when it was biding to the canal or when it was 1 mm short of binding.
  • The sequence of needles for each canal file size was as follows: 23-, 24-, 25-, 28-, and 30-gauge Max-i-Probe sidevent, 23- and 27-gauge Monoject end-notched needle.
  • A Monoject open-end, 30-gauge anesthetic needle was used as a control.
  • Most highlighted Results:

  • No needle design or gauge proved safe to use in either round or ovoid canals, regardless of stage of instrumentation .
  • Bonded needles gave higher pressure compared to loose ones.
  • Binding the needle within the canal gives higher pressures than with the needle slightly short of binding.
  • Greater danger exists for apical pressure escape for canal diameters larger than #30.
  • With the needle slightly withdrawn, larger bore needles caused higher pressures than small bore needles.

Clinical significance:

Vacuum drying is a much better/safer way to dry the canals