The Problem of Endodontically Treated Teeth

According to a survey done by the American Dental Association, there has been a vast increase in endodontically treated cases. This increase has been described by Ruddle as the ‘‘good news– bad news’’ dilemma. The ‘‘good news’’ is that hundreds of millions of teeth are salvaged through the combination of endodontics, periodontics, and restorative dentistry. The ‘‘bad news’’ is that tens of millions of endodontically treated teeth are failing each year for a variety of reasons. Therefore, the future of endodontics will include dealing with the retreatment of its failures. Removing all of the old obturation material is the most vital step of root canal retreatment procedures.

Traditionally, this objective has been accomplished using solvents like eucalyptus oil or xylol in combination with H files, heated instruments, GG drills, Peeso reamers and ultrasonics. Nevertheless, it is a tedious process that has recently been replaced by rotary NiTi files, including either standard files or those specially designed for retreatment procedures. Although these techniques can be considered as effective, the complete removal of filling material is not achieved, especially in the apical third portion of the root canal space and in narrow and curved canals. Thus, instead of creating an over enlarged canal, it is imperative to design and introduce a file that will adapt to the natural anatomy of the root canal space.

A new type of anatomic finishing file, the XP-endo Finisher R (FKG Dentaire, La Chaux-de-Fonds, Switzerland), was introduced for use as a final step in improving root canal cleaning after removal of previous obturation. It consists of a size #30 tip and a non-tapered rotary NiTi instrument made of a special alloy (MaxWire; Martensite- Austenite Electropolish Flex, FKG Dentaire). The file changes its shape according to the temperature. The file is straight, as it is in its martensitic phase (M-phase) at room temperature. However, when submitted to body temperatures, it enters its austenitic phase (A-phase) and assumes a spoon shape of 1.5 mm depth in the final 10 mm of its length.

The serpentine shape of the file and its resistance to cyclic fatigue makes it ideal for the removal of the core gutta percha for retreatment procedures.5 MTA Fillapex and AH Plus are classified as resin based sealers, presenting different compositions. AH Plus is an epoxy resin based sealer that has been considered the gold standard for its physical and chemical properties. While MTA Fillapex is a salicylate resin based sealer which contains mineral trioxide aggregate. The properties of root canal sealers have an impact on the quality of the final root filling. MTA Fillapex produces an alkaline pH, which may contribute to their osteogenic potential, biocompatibility, and antibacterial ability. It is one of the recently developed endodontic sealers which have only few reports available about its retreatment potential.

Thus, the aim of the study was to compare and evaluate the percentage of remaining endodontic sealers on the root canal walls using a XP- endo Finisher R file system as an adjunct and percentage and depth of the sealer penetration after retreatment. The null hypotheses of this study are: (1) there is no difference between sealer penetration after endodontic treatment and retreatment; (2) there is no difference in using ProTaper Retreatment File system with or without XP- endo Finisher R file system in removal of sealers.