Efficiency of the 0.04 taper ProFile during the re-treatment of gutta-percha-filled root canals
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Published on 08/1/2002
F. Baratto Filho, E. L. Ferreira & L. F. Fariniuk
Department of Endodontics, School of Dentistry, Pontificia Universidade Catolica of Parana, Curitiba, Parana, Brazil.
Aim.
The objective of this study was to determine the effectiveness of 0.04 ProFile instruments during the removal of root fillings.
Conclusions.
The 0.04 ProFile system partially removed filling materials from the root canal system allowing the working length to be achieved rapidly, with the advantage that no solvent was required. However, cleaning was not ideal and would require complementary manual instrumentation for total elimination of filling material.
Department of Endodontics, School of Dentistry, Pontificia Universidade Catolica of Parana, Curitiba, Parana, Brazil.
Aim.
The objective of this study was to determine the effectiveness of 0.04 ProFile instruments during the removal of root fillings.
Conclusions.
The 0.04 ProFile system partially removed filling materials from the root canal system allowing the working length to be achieved rapidly, with the advantage that no solvent was required. However, cleaning was not ideal and would require complementary manual instrumentation for total elimination of filling material.
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.
Introduction.
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:
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).
Department of Endodontics, School of Dentistry, Pontificia Universidade Catolica of Parana, Curitiba, Parana, Brazil.
Introduction.
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:
- Group I - Thermafil obturators size 30 (DentsplyMaillefer);
- Group II - thermomechanical compaction technique (Gutta Compactors, Dentsply Maillefer); and
- 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).
Results.
The previously determined working length was reached in all specimens. Fracture of one tooth occurred when using file 90, probably owing to the tooth dehydration, because the teeth were taken from laboratory stock which were stored dry.
Visually, by identification of remaining filling material on the longitudinal sections, and radiographically, it was possible to observe the following in the remaining 29 specimens:
Visually, by identification of remaining filling material on the longitudinal sections, and radiographically, it was possible to observe the following in the remaining 29 specimens:
- complete removal of the filling material occurred only in three specimens (two of group I and one of group II);
- twenty-six specimens had remaining gutta-percha and sealer on the canal walls; 90% of these specimens to the level of the cervical third and 10% to the level of the middle third;
- although the removal of gutta-percha was incomplete, ProFile reached the working length in all specimens;
- the removal of Thermafil plastic carriers was successful in all specimens of this group.
Table 1. Time required (min : s) to remove the filling material in the three groups.
Discussion - References.
Discussion.
The present study evaluated the removal of root canal filling materials with 0.04 ProFile system and whether the working length was reached. The fracture of two instruments in the cervical third was probably owing to errors in radicular access (insufficient opening) and the high frequency of use of the 0.04 ProFile instruments.
In the present study, the mean time required to remove the Thermafil plastic carriers was less than the half mean time reported in the study of Frajlich et al. (1998). The presence of a plastic carrier (group I) increased the average time needed to remove the filling material from the root canal (Bertrand et al. 1997, Ibarrola et al.1993,Wilcox1993). However, the Thermafil plastic carriers were removed totally.
According to Wilcox & Juhlin (1994), when solvents are used they form a thin film of filling material that is diffficult to detect and remove, which reduces the action of intracanal antibacterial medicaments. The proper adaptation of subsequent filling material on the root canal walls canal sobeimpaired. Thus, it is important to search for more efficient methods for the re-treatment of root canals.
The main disadvantage of this technique was the inability to adequately clean large root canals and canals that were not round. Because in most cases, incomplete removal of the gutta-percha and sealer was observed, the authors suggest that it was the result of anatomical features of the teeth used in this study. Also, owing to the fact that the ProFile system rotates 3608, we suggest the associated use of manual instruments such as hedstroem files (Weine,1998), to achieve complete removal of filling materials.
The present study evaluated the removal of root canal filling materials with 0.04 ProFile system and whether the working length was reached. The fracture of two instruments in the cervical third was probably owing to errors in radicular access (insufficient opening) and the high frequency of use of the 0.04 ProFile instruments.
In the present study, the mean time required to remove the Thermafil plastic carriers was less than the half mean time reported in the study of Frajlich et al. (1998). The presence of a plastic carrier (group I) increased the average time needed to remove the filling material from the root canal (Bertrand et al. 1997, Ibarrola et al.1993,Wilcox1993). However, the Thermafil plastic carriers were removed totally.
According to Wilcox & Juhlin (1994), when solvents are used they form a thin film of filling material that is diffficult to detect and remove, which reduces the action of intracanal antibacterial medicaments. The proper adaptation of subsequent filling material on the root canal walls canal sobeimpaired. Thus, it is important to search for more efficient methods for the re-treatment of root canals.
The main disadvantage of this technique was the inability to adequately clean large root canals and canals that were not round. Because in most cases, incomplete removal of the gutta-percha and sealer was observed, the authors suggest that it was the result of anatomical features of the teeth used in this study. Also, owing to the fact that the ProFile system rotates 3608, we suggest the associated use of manual instruments such as hedstroem files (Weine,1998), to achieve complete removal of filling materials.
References.
Aun CE, Santos M (1989) Quantity of apical extruded material and efficiency of five different methods of removing guttapercha and sealer from root canals - 'in vitro' evaluation. Revista Da Faculdade de Odontologia Da Zona Leste de SaoPaulo 1, 63-73.
Bertrand MF, Pellegrino JC, Rocca JP, Klinghofer A (1997) Removal of thermafil root canal filling material. Journal of Endodontics 23, 54-7.
Frajlich SR, Goldberg F, Massone EJ, Cantarini C, Artaza LP (1998) Comparative study of retreatment of thermafil and lateral condensation endodontic fillings. International Endodontic Journal 31, 354-7.
Friedman S, Stabholz A (1990) Endodontic retreatment - case selection and tecnique. Part 3. Retreatment techniques. Journal of Endodontics 16, 543-9.
Goerig A, Michelich RJ, Schultz HH (1982) Instrumentation of root canals in molar using the step-down technique. Journal of Endodontics 8, 550-4.
Ibarrola JL, Knowles KI, Ludlow MO(1993) Retrievability of thermafil plastic cores using organic solvents. Journal of Endodontics19, 417-21.
Imura N, Kato AS, Gata G-I, Uemura M, Toda T, Weine F (2000) A comparison of the relative efficacies of four hand and rotary instrumentation techniques during endodontic retreatment. International Endodontic Journal 33, 361-6.
Weine FS (1998) Tratamento Endodontico, 5th edn. Sao Paulo, SP, Brazil: Santos.
Wilcox LR (1993) Thermafil retreatment with and without chloroform solvent. Journal of Endodontics19, 563-6.
Wilcox LR, Juhlin JJ (1994) Endodontic retreatment of thermafil versus laterally condensed gutta-percha. Journal of Endodontics 20, 115-7.