Working length determination apex and the methods
- 1. WORKING LENGTH DETERMINATION Ahmed Hasan Ug : 1330077 therapeutic Dentistry IV
- 2. WORKING LENGTH DETERMINATION • The distance from a coronal reference point to the point at which canal preparation and obturation should terminate .
- 3. Anatomical considerations • Anatomic apex: it is defined as the tip or end of the root determined (Radiographic apex) • Apical foramen (physiological apex): it is the main apical opening of the root canal.when we make x-ray to the end of canal Distance between radograhic and physiological apex in the past time 0.5 mm but in the moderan time 1 mm to 2 mm
- 4. METHODS OF WORKING LENGTH DETERMINATION RADIOGRAPHICAL METHOD 1.Grossman’s formula 2. Ingles method 3.Weine’s method 4.Radiovisiography 5.Xeroradiography NON RADIOGRAPHICAL METHOD 1.Digital tactile sense 2.Apical periodontal sensitivity 3.Paper point method 4.Electonic apex locator
- 5. How we measure this length • First by x ray that taken while the file insert in canal and this situation apical foramen is usually found (0.5mm – 1mm ) from the radiographic apex so we need to decrease the length ( radiographic method )
- 6. Or by non radiographic Digital tactile sense • In this clinician may see an increase in resistance as file reaches the apical 2-3mm • Time saving, no radiation exposure • Do not provide accurate diagnosis always, resistance felt earlier in narrow canals, in case of teeth with immature apex instrument can go periapically
- 7. Apical 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.
- 8. Paper point measurement method • Most reliable in cases of open apex where apical constriction is lost because of perforation or resorption. • Moisture or blood present on apical part of paper point indicates paper point has passed beyond estimated working length. • Used as a supplementary method.
- 9. Electronic apex locator • is an electronic device used in endodontics determine the position of the apical constriction and thus determine the length of the root canal space • It giving the reading when the File tip at the apical foramen.
- 10. Causes of loss of working length • Presence of debris in apical 2-3 of canal • Failure to maintain apical patency • Skipping instrument sizes • Ledge formation • Inadequate irrigation • Instrument separation • Canal blockage
- 11. Reference • ENDODONTICS: PRINCIPLES AND PRACTICE, 4th Edition page ( 252 to 256) • Textbook of Preclinical Conservative Dentistry chapter 14 page ( 279- 281)
- 12. Thank you for your attention
Editor's Notes
- #7: When you insirt the file in to the root canal to the apical foramen we will fell the the thickness but we move it we make perforation and the file move down