Degradation of Resilon/RealSeal™ by Bacteria found in Endodontic Infections

Objectives:

Resilon/RealSeal (RS) is a resin based obturating material that claims to create a chemical bond between the dentin of the walls of the root canal, the sealer and the thermoplastic core material.  It attempts to create a “monoblock” of material that will seal the root canal system. RS is comprised of a biodegradable polymer, polycaprolactone and inorganic fillers, and has been shown to undergo degradation-hydrolysis by bacterial enzymes such as lipase. This study aims to demonstrate if bacteria observed in persistent AP can degrade RS using an agar disc hydrolysis method previously described. 

Methods:  

A RS emulsion was prepared and dispersed to make 0.1% RS in 1.5% Tryptic Soy Agar plates. Similar volumes of overnight cultures of P. intermedia, P. aeruginosa, P. assacharylitucus, S. aureus, S. epidermis, E. faecalis, F. nucleatum, S. mutans, S.sanguis and P. gingivalis were each inoculated in 8 spots on the agar plates.  The bacterial enzyme Lipase PS (Burkholderia cepacia) served as a positive control.

Results:  

P. intermedia, P. aeruginosa, P. assacharylitucus, S. aureus and S. epidermis all demonstrated hydrolytic halos at each of the 8 inoculation locations (100%) these bacteria were plated (95%CI 63%-100%).  The halos were similar to those seen with the positive lipase control and indicate hydrolysis of RS. The halos further developed with time as the colonies grew to a size of 6-8 mm in diameter after 4 days.  No halos were seen with E. faecalis, F. nucleatum, S. mutans, S. sanguis, or P. gingivalis at any of the 8 inoculation spots (0%) these bacteria were plated (95%CI 0%-37%).

Conclusions:

Bacteria found in endodontic infections can hydrolyze RS dispersed into an emulsion.

A potential exists for RS degradation in persistent/secondary endodontic infections.