Axis|SybronEndo's Soft-Core Endodontic Obturator is a core of biocompatible plastic coated with thermoplastic gutta percha. The obturator sizes 20 to 70 correspond to the ISO standards of root canal files. A single obturator is all that is needed to totally obturate a root canal, accurately with a tight apical seal.
The Soft-Core® plastic core is slightly oval-shaped. This secures adequate backflow of the heated gutta percha. The length of the core is 24 mm. The coronal 6 mm of the core is hollow to accommodate the metal insertion pin. A rubber endo stop is provided to indicate the working distance measurement. The plastic core and gutta percha are radiopaque.
Application
Before using the Soft-Core Endodontic Obturator, assure that you have achieved a properly cleaned and shaped canal that is completely dry with an established working length.
Step 1: Determine the working length and select the appropriate size of obturator
The working length is measured all the way to the apex. Measure the working length from the edge of the cusp. The working length can advantageously be measured by use of both x-ray, file and electronic apex locator. Soft-Core® Size Verifiers are radiopaque and can be used for working length verification.
Generally, the appropriate size Soft-Core Endodontic Obturator will be the same size as the last file used at the apex of the canal.
Tip: For very narrow and/or highly calcified canals, it may be useful to select one size smaller than the last file used at apex. If you do not use rotary files with a taper of 4% or more, you should always verify the size of the cleaned root canal with a size verifier before inserting the obturator.
When the size verifier has a slightly loose fit in the apical third, the rubber stop is placed at the working length. Afterwards, the working length is transferred to the obturator. Soft-Core obturators and Size Verifiers are the exact same length.
Step 2: Heat the obturator
Place the selected obturator in the Soft-Core® heater and activate the heater.
Step 3: Apply the sealer
While the obturator is heating, mix any heat resistant sealer with long working time (a non-eugenol sealer is recommended). Make sure the root canal is completely dry, before applying sealer. Place a very thin coating of sealer on the wall of the canal using a paper point or a Soft-Core Size Verifier. Too much sealer is neither desirable nor necessary. When obturating more than one canal, apply sealer in all canals at once.
Step 4: Insert the obturator into the canal
When the heater indicates that the obturator is ready for use, the obturator may be removed. Immediately insert the obturator into the canal to the working distance with firm, steady pressure and without twisting the handle.
Important: The obturator should be inserted to the full working length.
Step 5: Remove the handle, excess central core, and gutta percha
The handle, excess core and gutta percha may be removed once the gutta percha has hardened. For canals less than 18 mm, twist the handle and plastic core to one side to break off the excess. For all Canals, stabilize the plastic core with a finger or cotton pliers, and cut away the handle and excess plastic core with a small inverted cone bur.
Important: Be careful to prevent vertical movement of the core to minimize the chance of disturbing the apical seal. Trim away the extra gutta percha using an endo excavator or similar instrument.
Step 6: Take x-rays to confirm treatment
This article is adapted from materials provided by Axis|SybronEndo.