ABSTRACT
The aim of this study is to analyze and compare the efficacy of three non-surgical endodontic retreatment techniques in removing a carrier-based root canal filling material from straight root canal systems. The study was performed on 99 single-rooted extracted teeth using the ProTaper Gold endodontic rotary system up to the F2 file (Dentsply Maillefer, Baillagues, Switzerland), which were sealed with GuttaCore (Dentsply Maillefer, Ballaigues, Switzerland) and AH plus epoxy resin sealer (Dentsply DeTrey, Konstanz, Germany) and randomly assigned to the following non-surgical retreatment techniques: ProTaper Retreatment endodontic rotary instruments (D1-D3 files, Dentsply Maillefer, Ballaigues, Switzerland; n = 33, PTR), Reciproc Blue endodontic reciprocating instrument (R50, VDW, Munich, Germany; n = 33, RCB50), and a combined root canal retreatment technique between Gates-Glidden drills (sizes #3 and #2, Dentsply Maillefer, Ballaigues, Switzerland) and Hedstrom files (file size 35, 30, and 25, Dentsply Maillefer, Ballaigues, Switzerland; n = 33; H-GG). All of the teeth were submitted twice to a micro-computed tomography (micro-CT) scan, before and after non-surgical endodontic retreatment procedures. The volume of root canal filling material (mm3), volume of remaining root canal filling material (mm3), non-surgical endodontic retreatment working time (min), proportion of remaining root canal filling material (%), and efficacy of root canal filling material removal between the non-surgical endodontic retreatment techniques were analyzed using ANOVA one-way statistical analysis. Statistically significant differences were observed between the proportions of remaining root canal filling material of PTR and H-GG (p = 0.018), between the non-surgical endodontic retreatment working times (min; p < 0.001), and between the efficacies of root canal filling material removal by the non-surgical endodontic retreatment techniques (p = 0.009). However, the non-surgical endodontic retreatment systems allow for similar carrier-based root canal filling material removal.
ABSTRACT
BACKGROUND: When endodontic treatment fails, retreatment consists of the complete removal of the root canal filling material for thorough cleaning and reobturation. Various techniques are available for the filling removal procedure, which present varying degrees of efficacy, and take a varying length of time to perform. The aim of this study was to compare the time required to carry out reciprocating, rotary, and manual techniques with dental microscope and ultrasonic activation for removing filling material from root canals. MATERIAL AND METHODS: Ninety-nine extracted single-rooted teeth with straight and oval-shaped canals were selected. The samples were instrumented with ProTaper Gold System up to file F2 and obturated with AH Plus sealer and GuttaCore. The teeth were randomly divided into three groups (n=33) according to the instruments used for removal of filling material: Group (1) Reciproc blue R50 instrument; Group (2) ProTaper Retreatment instruments; Group (3) manual (Hedstrom files and Gates-Glidden drills), under dental microscope at X10 magnification with Ultrasonic retreatment tip. The time required to remove the filling materials was measured with a chronometer. Data were analyzed statistically applying the Kruskal-Wallis test followed by the Mann-Whitney U-test (p<0.05). RESULTS: The time required to remove filling material was significantly shorter in Group 1, followed by Group 2, the slowest being Group 3 (P<0.05). CONCLUSIONS: The reciprocating technique was the fastest method for removing root canal filling material. Key words:Endodontic retreatment, hedstrom file, ProTaper retreatment, reciproc blue.
