Re-treatment

The first step of any re-treatment procedure is the removal of previous root filling material to allow for proper cleaning, disinfection, and obturation of the root canal.

Studies show that the removal of gutta-percha with commonly used rotary, reciprocating or hand instruments is likely to leave remnants of gutta-percha and sealer attached to the canal walls.

The use of the SAF after any other retreatment instrument will improve the efficacy of gutta-percha/sealer removal and leave significantly less root filling residue on the walls of the root canal. This is especially important in curved canals, whose curvature limits the visual evaluation of canal wall cleanliness, even when a microscope is used.

The following are two examples of re-treatment using popular methods. This is not intended to be an all-inclusive description of re-treatment techniques. Note that all re-treatment techniques require the use of another instrument to remove the bulk of gutta-percha prior to the use of SAF and that the goal of re-treatment is to remove all of the filling material without leaving residue, while minimally widening the already-prepared root canal.

1. Method 1 (Shemesh et al., JOE 2012) – NiTi rotary instruments followed by SAF without solvent :
   1. Use NiTi rotary retreatment instruments (ProTaper/ProFile/other instruments) to remove the bulk of gutta-percha without the use of any solvent.
   2. Irrigate the canal after each instrument with 2 mL of NaOCl 2%-4%.
   3. Continue by using SAF 2.0 mm for 1 min without irrigation, followed by 4 min with continuous NaOCl irrigation at a flow rate of 4 mL/min.

1. Method 2 (Abramovitz et al., Int Endod J 2012; Solomonov et al, JOE 2012) – NiTi rotary instruments followed by SAF with solvent:
   1. Use NiTi rotary instruments to remove the bulk of gutta-percha.
   2. Use the SAF 2.0 mm for 1 min with NaOCl irrigation at a flow rate of 4 mL/min.
   3. Dry the canal, place 1 drop of solvent (chloroform) in the canal, and operate the SAF again for 1 min with the irrigation pump turned off. Place another drop of solvent in the canal and use the SAF again for 1 min without irrigation and then for an additional 30 seconds with NaOCl irrigation. Flush the canal with 1 mL 17% EDTA and use the SAF for another 30 seconds with the irrigation turned off. Finish with additional 1 min SAF operation with continuous NaOCl irrigation.

Other methods to remove the bulk of the root canal filling may also be used, followed by the SAF.