Effect of Preflaring on Tactile Detection of the Apical Constriction

By Stabholz A, Rotstein I, Torabinejad M

Date: 01/1995
Journal: JOE


To test the effect of preflaring on tacticle detection of apical constriction

N = 120 root canals


Exclusion criteria: complicated anatomy, external root resorption, severe root curvature

M&M: No pre-op xray shown to operator à #15 or 20 k file used to feel apical constriction à radiograph taken to verify.

Group 1 (68 canals) = no flaring

Group 2(52 canals) = flaring by hedstrom, Gates 2 & 4, ultrasonic

Evaluation criteria:

(A)within 1 mm of radiographic apex

(B)(B) short ≥ 1 mm

(C)(C) overextended


Preflaring increased tactile ability to detect apical constriction (ss)

Clinical Significance:

  • Preflaring can reduce the # of radiographic images needed to determine WL, and reduces the chance of overtension which can cause periapical injury and inflammation.
  • Less relevant with use of apex locaters.
  • Preflaring helps achieve an accurate working length.