Self-adjusting files in retreatment: a high-resolution micro-computed tomography study.
BACKGROUND
Rotary instruments that are used for retreatment are very effective, but most of them leave root filling residue in the canal. The aim of this study was to evaluate the efficacy of removing gutta-percha-based root fillings with ProTaper retreatment files (Dentsply Maillefer, Ballaigues, Switzerland) followed by F1 and F2 ProTaper instruments and to compare these results with those obtained with a #25 .06 ProFile instrument (Dentsply Maillefer) followed by the Self- Adjusting File (SAF; ReDent, Ra'anana, Israel) using high resolution micro-computed tomography (CT) scanning.


METHODS
Twenty-eight mandibular molar teeth with oval distal root canals were divided into 2 equal groups of 14 teeth each. The distal root canals were instrumented with ProTaper files up to an F2 instrument, the roots were subsequently filled, and the root filling was allowed to set fully. Removal of the root canal filling was performed with D1-D3 ProTaper retreatment files followed by F1 and F2 ProTaper instruments or with a #25 .06 ProFile followed by SAFs. Chloroform was used in both groups to assist in the removal of the root filling material. High-resolution micro-CT scans were used to measure the residual quantities of the root filling material after completion of the procedures. Statistical analysis was performed using the Wilcoxon test and the Student t test.


RESULTS
The median root filling residue in the ProTaper group was 5.39% (interquartile range [IQR] = 4.71) of the original volume of the root canal filling. In the ProFile and SAF group, the median residue was 0.41% (IQR = 1.64, P < .001). An arbitrarily selected threshold of less than 0.5% residue was defined as "effectively cleaned," and 57% of the teeth treated with the ProFile and the SAF met this threshold, whereas none of the cases in the ProTaper group did. The ProFile and SAF procedure required less time than the ProTaper protocol.


CONCLUSIONS
None of the retreatment methods rendered all of the canals completely free of all root filling residue. Under the conditions of this study, the ProFile and SAF procedure was more effective than the ProTaper procedure and left significantly less root filling residue in the root canal.
Department of Endodontics, Sheba Hospital, Tel Hashomer, Israel. mishasol@gmail.com
Michael
M
Solomonov
Frank
F
Paqué
Sadullah
S
Kaya
Ozkan
O
Adigüzel
Anda
A
Kfir
Senem
S
Yiğit-Özer
D002725:Chloroform / Q000627:therapeutic use; D003786:Dental Pulp Cavity / Q000648:ultrastructure*; D003804:Dentin / Q000648:ultrastructure; D004492:Edetic Acid / Q000627:therapeutic use; D004853:Epoxy Resins / Q000627:therapeutic use; D004867:Equipment Design; D006171:Gutta-Percha / Q000737:chemistry*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods; D019233:Retreatment; D012387:Root Canal Filling Materials / Q000737:chemistry* / Q000627:therapeutic use; D012388:Root Canal Irrigants / Q000627:therapeutic use; D012389:Root Canal Obturation / Q000379:methods; D018915:Root Canal Preparation / Q000295:instrumentation* / Q000379:methods; D012973:Sodium Hypochlorite / Q000627:therapeutic use; D012997:Solvents / Q000627:therapeutic use; D013499:Surface Properties; D013997:Time Factors; D055114:X-Ray Microtomography / Q000379:methods
D004853:Epoxy Resins; D012387:Root Canal Filling Materials; D012388:Root Canal Irrigants; D012997:Solvents; C534916:epoxy resin-based root canal sealer; D002725:Chloroform; D006171:Gutta-Percha; D004492:Edetic Acid; D012973:Sodium Hypochlorite