There are several radiographic and non-radiographic methods to determine working length described in the document. The radiographic methods include Ingle's technique, Grossman's method, Kuttler's method, and the radiographic grid method. Electronic apex locators and tactile sense are two non-radiographic methods mentioned. The document recommends that a combination of an electronic apex locator and Ingle's radiographic technique provides the most accurate determination of working length. It advises against relying solely on non-radiographic methods.

1. Working length determination
Presented by: Shrisha Pant

2. Methods of Determining Working
Length
1. Radiographic methods
a Ingle’s technique (Recommended)
b. Others –
Best’s method
Bregman’s method
Bramante’s technique

3. Grossman’s method
Weine’s method
c. Kuttler’s method
d. X-ray grid method
e. Endometric probe
f. Xeroradiography
g. Direct digital radiography
2. Electronic apex locators

4. 3.Nonradiographic methods (not recommended)
a. Digital tactile sense method
b. Apical periodontal sensitivity
c. Paper point method
d. Average tooth length

5. Weine’s Modification method
Modification in Ingle’s Method
where final working length under following condition
obtained by:
No resorption cases : subtract1mm
Periapical bone resorption : subtract1.5mm
Periapical bone and root apex resorption : subtract
2mm , for compensation of loss of apical constriction.

7. Grossman method
It is based on simple mathematical formulation to calculate the working
length:
An instrument is inserted into the canal
Stopper is fixed to the reference point
Radiograph is taken
The formula used for calculation of actual length is as follows:

8. Actual length of tooth = Apparent length of tooth in radiograph
Actual length of instrument Apparent length of instrument in radiograph
Actual length of the tooth= actual length of the instrument X apparent length of the
t tooth in radiography
Apparent length of instrument in radiograph

9. Kuttler’s method
• According to Kuttler’s canal preparation should terminate
at apical constriction(minor diameter).
locate the minor and major diameter on preoperative
radiograph
Estimate length of roots from preoperative radiograph
Estimate canal width and insert no.10 or 15 file in canal up
to estimated length

10. take a radiography
If file is too long or short by more than 1mm from the minor
diameter , readjust the file and take another radiograph
If file reach the major diameter , subtract 0.5 mm from it for
younger patients and 0.6mm for older patient

11. Advantage
1.Allows rapid development of apical dentinal
matrix
2.Minimal error
3.Has shown many successful result.
Disadvantage
1.Time consuming
2.Calculation is complicated
3.Radiograph of excellent quality and
magnification is required.

12. Radiographic grid method
• Designed by Everett & Fixott in1963
• It is a simple method in which a millimeter grid is
superimposed on the radiograph.
• This over comes the need for calculation.
• But it is not good method if radiograph is bent during
exposure

13. ADVANTAGES :
Simple method
No need for calculations
DISADVANTAGES :
Cannot be used if radiograph is bent during
exposure

14. Endometric Probe
• In this method, one uses the graduations on
diagnostic file which are visible on radiograph.
• But its main disadvantage is that the smallest
file size to be used is number 25.

15. Xero-radiography
• The term Xero-radiography is derived from the Greek
word XEROS which literally means dry which
differentiates this from the conventional photochemical
system.
• Images are recorded on an aluminum plate coated with
selenium particles.
• Image are sharper.
• Edge enhancement improves the visualization of files and
various anatomical structure such as apical foramen and
periodontal ligament.

16. The aluminum plate is removed from the cassette
subjected to relaxation which removes old images
These are electrostatically charged
Inserted into cassette
Projection of radiation
Forms latent image and is converted to real images by
process called ‘development’ in the processor unit.

17. Direct digital radiography
• In this digital image is formed which is
represented by spatially distributed set of
discrete sensors and pixels.
• Two types of digital radiography:
a. Radiovisiography
b. Phosphor imaging system

18. ADVANTAGES of radiographic method
1.Can see anatomy of tooth
2.Can see curvature in roots
3.Can see relationship b/w adjacent teeth & anatomic
structures
DISADVANTAGES of radiographic method
1.Varies with different observers
2.Superimposition of anatomic structures
3.2D view of a 3D object
4.Radiation exposure
5.Cannot interpret if apical foramen has buccal or lingual
exit
6.Limited accuracy
7.Time consuming

19. Non radiographic method
1. Digital Tactile method
• There is increase in
resistance as the film
approaches apical 2-3mm.
• In this region the canal
frequently constricts (minor
diameter).
• Adjunct to radiograph or
apex locator.

20. ADVANTAGES :
• Time saving
• No radiation exposure
DISADVANTAGES :
• Does not always provide the accurate readings.
• In case of narrow canals, one may feel increased
resistance as file approaches apical 2-3 mm.
• In case of teeth with immature apex instrument can
go periapically

21. 2.Paper point measurement
• Most reliable in cases of open apex where apical constriction
is lost because of perforation or resorption.
• Blunt end of paper point is passed gently in canal after LA.
• Moisture or blood present on apical part of paper point
indicates paper point has passed beyond estimated working
length.

22. This method, however, may
give unreliable data :
1. If the pulp not
completely removed.
2. If the tooth is pulp less
but a periapical lesion
rich in blood supply is
present.
3. If paper point is left in
canal for a long time

23. 3.Periodontal sensitivity test
Based on patient’s response to pain
• This method does not provide accurate readings,
for example in case of narrow canals, instrument
may feel increased response in apical 2-3mm,
immature apex, file goes beyond apex.
• In case of canals with necrotic pulp, instrument can
pass beyond apical constriction, and in case of vital
or inflamed pulp, pain may occur several mm
before periapex is crossed by instrument

24. 4.Average tooth length
It can be taken as a guideline.

25. Conclusion
• There are several method to determine working
length.
• Combination of electronic apex locator and ingle’s
radiographic technique is most appropriate
technique.
• Non radiographic method is not recommended.

26. Reference:
• Grossman’s ENDODONTIC PRACTICE , 13TH
EDITION
• Textbook of Endodontics , 2ND EDITION pg no
204-205