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Azerbaycan Saytlari

 »  Home  »  Endodontic Articles 8  »  Efficiency of the 0.04 taper ProFile during the re-treatment of gutta-percha-filled root canals
Efficiency of the 0.04 taper ProFile during the re-treatment of gutta-percha-filled root canals
Introduction - Materials and methods.

F. Baratto Filho, E. L. Ferreira & L. F. Fariniuk
Department of Endodontics, School of Dentistry, Pontificia Universidade Catolica of Parana, Curitiba, Parana, Brazil.

One of the greatest technical difficulties faced by endodontists is conventional root canal re-treatment, as the filling materials represent a mechanical barrier that can often require considerable time and effort to remove. A variety of techniques have been used to remove root filling materials including stainless steel hand instruments alone or combined with solvents (Friedman & Stabholz 1990), endosonics (Aun & Santos 1989) and rotary devices (Imura et al. 2000). The various filling techniques that are now available has complicated re-treatment procedures. In general terms, the movement from single cone cold gutta-percha techniques to coated carrier and warm vertical condensation techniques has made it more difficult to remove root fillings during re-treatment.
The purpose of this study was to evaluate the efficiency of the 0.04 taper ProFile instruments during the removal of gutta-percha from root canals.

Materials and methods.
A total of 30 single-rooted mandibular canine teeth with straight canals were selected for study. Root canals were prepared using a step-down technique (Goerig et al. 1982).The cervical and the middle-thirds were prepared with sizes 1-3, Gates Glidden burs (Dentsply Maillefer, Ballaigues, Switzerland) in a telescopic preparation. The apical third was prepared using Nitifiex ¢les (Dentsply Maillefer) with an automated device (3 LD head and 3624 angular piece; KaVo, Biberach, Germany) which had a reciprocating action of 908. The master apical ¢le was size 40. All preparations were performed by one individual.
After preparation, the specimens were obturated using three different techniques:
  1. Group I - Thermafil obturators size 30 (DentsplyMaillefer);
  2. Group II - thermomechanical compaction technique (Gutta Compactors, Dentsply Maillefer); and
  3. Group III - lateral condensation technique.

Thermafil (group I).
In the Thermafil technique (group I), a size 30 verifier was placed in the root canal to the working length. This length was then transferred to a Thermafil carrier. After drying the canal, Sealer 26 (Dentsply, Petropolis, Brazil) was applied to the walls and the obturator was heated and then inserted into the canal to the working length. The carrier was cut at the canal orifice using a diamond bur number 1014 (KG Sorensen, Barueri, Brazil).A radiograph was taken with the X-ray cone positioned perpendicular to the tooth in the buccolingual direction.

Thermomechanical compaction (group II).
After selection of the master cone and the Gutta Compactor of the same size, Sealer 26 was applied to the root canal walls. The master cone (size40,Tanari,Tanariman, Manacapuru, Brazil) was cemented at the working length, and space created with a finger spreader. The compactor was introduced and then activated until the heat caused by the friction of the compactor with the root dentine softened the gutta-percha. The compactor was removed and the gutta-percha was compacted vertically using a size 1 vertical plugger. Excess material was removed with a heated vertical plugger. A radiograph was then taken as described previously.

Lateral condensation (group III).
After application of sealer to the canal walls and cementation of a size 40 master cone, space was created with the aid of a spreader, and accessory cones inserted until the canal was full. Excess material was removed with a heated vertical plugger and radiographs were again taken as described previously.

Removal of fillings with the 0.04 ProFile System.
All teeth were stored dry at room temperature. Two weeks later, the filling of all specimens was removed using the 0.04 ProFile system (Dentsply Maillefer). A size 90 ProFile instrument followed by sizes 60, 45, 40, 35 and 30was used at a speed of 300 rpm in a crown-down manner to the previously established working length. One series of ProFile instruments was used per group. The time required to remove filling material and achieve the working length was recorded. Radiographs were again taken in the buccolingual direction with the Xray cone positioned perpendicular to the tooth to evaluate the effectiveness of this procedure.
After removing the filling material, the teeth were grooved longitudinally with caborundum disks and split with a chisel. A hyper colour video camera (10x) (Sony, Tokyo, Japan) connected to a colour video printer (Mavigraph 1B 1200 A, Sony) recorded and then printed images from the cut specimens. This equipment also amplified the images to analyse the quality of removal of filling material in each group. Two examiners, who were unaware of the origin of the experimental groups, recorded the quality of filling removal from each third of the root in terms of the absence or presence of filling material (indicated by colour of remaining material). They also sought to identify Thermafil plastic carrier (group I) because the literature refers to the difficulty in removing carriers of this system.
The time required to remove the fillings was recorded and submitted to statistical analysis (anova and Tukey’s test).