•Resorcinol-formaldehyde (RF) is a combination of formaldehyde/ alcohol, resorcinol powder, and a sodium hydroxide catalyst.
Purpose: to understand the material and techniques related and considerations to be taken when evaluating and retreating RF
Components of RF:
•Formaldehyde : cause histopathologic fixation of the remaining pulp tissue, also an effective antimicrobial agent against bacteria, fungi, and virus . But its efficacy depends on the condition of the pulp because it binds to organic matter. Highly toxic and can cause significant inflammation to connective tissue .
•Resorcinol: white powder that has many uses in medicine when combined with formaldehyde (i.e closing wound, seal pulmonary air leakage). In dentistry , used to arrest caries. Its some are allergic to it, it cause bone sequestration(in direct contact).
•RF discolors the tooth (pink-burgundy), it is radiolucent but radiopacifiers are added (zinc oxide or barium sulfate).
•The resin purportedly permeates infected root canals and destroys bacteria, “resinifies” residual pulp tissue rendering it harmless, obturate the canal, and prevents reinfection. Advantages of this technique include eliminating the need for complete pulp tissue removal and antibacterial additives .
Some examples of teeth treated with RF (fig 1-3)
Retreatment of RF:
Retreatment on RF treated teeth can be an unpredictable :
-It could be completely unpolymerized or incompletely polymerized which could be retrieved with ease
-fully polymerized resin is very hard and can be difficult to remove , and there is no solvent that fully polymerized RF removal