Incidence of flare-ups and evaluation of quality after retreatment of resorcinol-formaldehyde resin (“Russian Red Cement”) endodontic therapy

By Gound TG, Marx D, Schwandt NA

Date: 12/2003
Journal: JOE

Purpose: to determine the immediate treatment result and incidence of flare-ups after retreatment of teeth with resorcinol-formaldehyde (RF) resin fillings.

N= 58 cases of retreatment of root filled with RF resin material


•Records of 34 patients with 58 teeth that were filled with RF and retreated in a postgraduate endodontic clinic were reviewed.

•Reason for retreatment (symptoms versus restorative) and occurrence of flare-ups (pain or swelling requiring an emergency visit) and the periapical status before retreatment were recorded.

•Radiographs were taken for initial (resin obturations) and posttreatment (gutta-percha obturations) evaluations were used.

•Before & after retreatment, the length of obturated canal was measured by starting at the coronal orifice and measuring to the apical-most extent of the filling. The length of unobturated canal(s) was measured from the apical-most extent of the filling to a point 1-mm from the radiographic apex of the root. The % of the filled canal space was calculated.

•After retreatment quality of obturation was rated as optimal if 100% of the canals were filled, improved if the percentage of canals filled was increased by at least 10%, unchanged if the increase in percentage of canals filled was <10%, and worse if an iatrogenic perforation or separated instrument occurred.

Most highlighted Results: 

  • 48% of the total canal space was filled before retreatment; 90% was filled after retreatment.
  • After retreatment, obturations were rated as optimal in 59%, improved in 33%, unchanged in 6%, and worse in 2%.
  • 12% had post-retreatment flare-ups.
  • No statistical relations was found  between the incidence of flare-ups and the quality of obturation before or after retreatment (in terms of length) or the presence of symptoms or PA lesions before retreatment.

Clinical significance:

Studies with larger sample size are needed to determine the variables related to flare up.