INGLE’S RADIOGRAPHIC METHOD OF WORKING LENGTH DETERMINATION

Written by : Dr. Urusa I Inamdar

Diagnostic radiograph of tooth used to estimate the working length by measuring the tooth from a stable occlusal reference point till radiographic apex

Subtract atleast 1 mm from this length as minor constriction is present short of the anatomic apex and compensation for radiographic image distortion.

This measurement is transferred to a diagnostic instrument with a silicon stop then placed in the root canal and working length radiograph is taken.

Now measure the difference between the end of the instrument and radiographic apex of the root , on the radiograph.

Tip of the instrument ends 0.5 mm – 1 mm from the radiographic root apex – working length established .

  • Short of the radiographic apex by more than 1.0 mm – then add this value to the earlier estimated length and adjust the stopper on diagnostic instrument accordingly.
  • Beyond the radiographic apex – reduce this value from the earlier estimated length and adjust the stopper on diagnostic instrument.

Retake the working length radiograph .

Weine’s modification:

  • If periapical bone resorption is evident in a radiograph , the working length should be reduced 1.5 mm short of the radiographic apex as the apical constriction would have been destroyed by the resorption .
  • If apical root resorption is seen , the working length is reduced to 2 mm short of the radiographic apex , in such an event , an apical stop is created short of the radiographic apex to prevent overinstrumentation and subsequent overfilling of the root canal .

https://youtu.be/fcKelPcZzds

Reference:

  • Grossman’s Endodontic Practice (13th edition)
  • Dental notes
  • Youtube.com

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