Effectiveness of rotary or manual techniques for removing a 6-year-old filling material

Abstract

The aim of this study was to evaluate the effectiveness of manual and rotary instrumentation techniques for removing root fillings after different storage times. Twenty-four canals from palatal roots of human maxillary molars were instrumented and filled with gutta-percha and zinc-oxide eugenol-based sealer (Endofill) , and were stored in saline for 6 years. Non-aged control specimens were treated in the same manner and stored for 1 week. All canals were retreated using hand files or ProTaper Universal NiTi rotary system. Radiographs were taken to determine the amount of remaining material in the canals. The roots were vertically split, the halves were examined with a clinical microscope and the obtained images were digitized. The images were evaluated with AutoCAD software and the percentage of residual material was calculated. Data were analyzed with two-way ANOVA and Tukey's test at 5% significance level. There was no statistically significant differences (p>0.05) between the manual and rotary techniques for filling material removal regardless the ageing effect on endodontic sealers. When only the age of the filling material was analyzed microscopically, non-aged fillings that remained on the middle third of the canals presented a higher percentage of material remaining (p<0.05) compared to the aged sealers and to the other thirds of the roots. The apical third showed a higher percentage of residual filling material in both radiographic and microscopic analysis when compared to the other root thirds. In conclusion, all canals presented residual filling material after endodontic retreatment procedures. Microscopic analysis was more effective than radiographs for detection of residual filling material.

Micro-CT evaluation of the effectiveness of the combined use of rotary and hand instrumentation in removal of Resilon

“…This may be attributed to the equal effectiveness of this technique in removal of Resilon with both obturation techniques. Previous studies which compared the effectiveness of hand with rotary instrumentation reported contrasting results 13,26,27) . This may be due to differences in the rotary systems tested, type of hand file and time allowed for setting of sealers.…”

Accuracy and Reliability of Intraoral Radiographs in Determining the Cleanliness of Root Canals after Endodontic Retreatment

“…This is in accordance with previous studies. Duarte et al evaluated the effectiveness of rotary or manual techniques for removing root fillings and found that microscopic analysis detected a significantly higher percentage of residual filling material than radiographs (8).…”

“…mography (micro-CT) and computed tomography (7)(8)(9)(10). Micro-CT is a novel non-invasive technique, which may have the potential to reveal the truth about the effectiveness of root-filling removal of different root canal retreatment procedures (11,12).…”

Micro-computed tomographic evaluation of removal and extrusion of root filling material during canal retreatment

“…Anatomical complexities can challenge root canal preparation due to the limitations on the appropriate adaptation of files in the canal (PEREIRA et al, 2012). Indeed, complete removal of root fillings can also be influenced by difficulties imposed to the action of files in some irregular regions of the canal walls presenting irregularities (DUARTE et al, 2010) (Figure 1). This fact is probably responsible for the several controversies existing among different studies, since root canal anatomy can influence the amount of remaining filling material after retreatment, irrespective of the technique used (BARRIESHI-NUSAR, 2002; GIULINI, COCHETTI; PAGAVINO, 2008;HAMMAD, QUALTROUGH, SILIKAS, 2008).…”