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RSBO (Online)

versão On-line ISSN 1984-5685

RSBO (Online) vol.11 no.4 Joinville Out./Dez. 2014




Evaluation of four gutta-percha removal techniques for endodontic retreatment



Janaína Barros Alves Medeiros I; Marilisa Carneiro Leão GabardoI; Sergio Herrero Moraes I; Maria Isabel Anastácio Faria I

I Course of Specialization in Endodontics, Herrero School– Curitiba – PR – Brazil





Introduction: The endodontic retreatment is the first choice in cases of endodontic treatment failure. Objective: To evaluate the ability of removing gutta-percha from root canal walls, through analyzing the time and different techniques. Material and methods: Sixty extracted human mandibular pre-molars were used. After instrumentation with crown-down technique, the obturation was performed by Tagger's hybrid technique. The specimens were divided into 4 groups (n = 15), according to removal procedure: group I (manual + solvent), group II (manual + Gates-Glidden + solvent), group III (Protaper Universal Retreatment System) and group IV (Protaper Universal System + solvent). The time period for gutta-percha removal was measured with a stopwatch. The roots were sectioned and the remnants were visually evaluated, according to the following scores: 0 – without remnant, 1 – presence of only cement, 2 – presence of cement and gutta-percha in small amounts, and 3 – presence of cement and gutta-percha in large amounts. Data were statistically evaluated with the GraphPad InStat software. Results: Group II exhibited the shortest time of execution, with significant differences in relation to groups I and IV, which obtained the longest time periods. Group III showed an intermediate time period, with statistically significant differences in relation to group IV. Group IV obtained the best scores of cleaning, although there was no statistical difference among groups. Conclusion: There was no statistical significant difference among the techniques regarding the time and effectiveness in removing filling material from the root canal walls.

Keywords: retreatment; gutta-percha; methods.




The technologic advancement in Dentistry has allowed high indexes of endodontic treatment success. Notwithstanding, some cases still require endodontic retreatment.

Many factors lead to endodontic treatment failure, such as reinfection, contamination of root canal systems already filled 2,4,16,19,20, and incomplete obturations 9,13,27,29. Conventional retreatment is the first choice in these cases 2,3,5,9,14,17,18,20,22,26,27, with favorable long-term results 21,30.

Endodontic treatment goal is re-access the apical foramen, by completely removing the obturation, making easy the cleaning and shaping of the root canals 5,9,18,19.

Gutta-percha can be removed by many manners: solvents 9,13,18,20, Gates-Glidden drills 32,34, ultrasound 21, and motor-driven rotary instruments 1-9,11-13,15-20,24-26,28,30,32-35.

Searching an adequate retreatment system, Protaper Universal Retreatment System was launched with proper instruments for this purpose 11,15,17,33. These files have a convex triangular cross-section 26 similar to that of conventional Protaper files S and F. Moreover, D1 file has active point, making easy its initial penetration in the filling material 16,17. This design improves the instrument's performance in terms of removing the filling material 24.

Although specifically developed for endodontic retreatment, some studies have evidenced that rotary instruments show the same efficacy of hand files, but with shorter working time 4,8,26-28,30. Other studies have demonstrated that the flexibility, cutting, resistance to fracture, and instrument diameter influence on the filling material removal 3,23,27. By comparing the velocity of filling material removal, it is believed that rotary instruments are more effective because of the guttapercha plasticization due to the heating generated by the rotation 5,8,11,18,27,30. However, the complete material removal is difficultly achieved and remnants are found, regardless of the rotary technique employed 11,15,33,34.

Thus, this study aimed to evaluate the capacity of gutta-percha removal from root canal walls in extracted human mandibular pre-molars and the time required for this purpose, through four different techniques: manual + solvent, manual + Gates-Glidden + solvent, Protaper Universal Retreatment System, and Protaper Universal System + solvent.


Material and methods

This research was approved by the Ethical Committee in Research of the Brigadeiro Eduardo Campos Aeronautics Gerontological Home (CGABEG), under protocol no. #0004.0.339-000-11.

One single examiner previously calibrated executed all study phases. Sixty extracted human mandibular pre-molars were selected according to the shape and length of the root. The teeth were radiographed at proximal direction and those presenting more than one root canal, incomplete roots, marked curvature and marked flattening were excluded.

The teeth were transversally cut at cervical portion, close to enamel-cementum junction, with the aid of carborundum disc (SS White Company, Philadelphia, USA) coupled to straight handpiece (Dabi Atlante, Ribeirão Preto, Brazil), under air/ water refrigeration, so that the root length was standardized at 16 mm.

Working length was determined with the aid of a size #15 Flexofile instrument (Dentsply-Maillefer, Ballaigues, Switzerland), introduced into root canal up to apical foramen and then set back 1 mm.

The canals were instrumented by crown-down technique. Both the cervical and medium thirds were prepared with the aid of size 2 and 3 Gates Glidden drills (Dentsply-Maillefer, Ballaigues, Switzerland), and apical third was prepared up to size #40 Flexofile instrument (Dentsply-Maillefer, Ballaigues, Switzerland). During instrumentation, irrigation was accomplished with 2 ml of 1% sodium hypochlorite (Farmadoctor, Curitiba, Brazil), at every instrument change. Concluded the instrumentation, the canals were irrigated with 10 ml of EDTA (Farmadoctor, Curitiba, Brazil).

The specimens were filled by Tagger's hybrid 29, with the aid of size #50 MacSpadden plugger (Dentsply-Maillefer, Ballaigues, Switzerland), with size #40 gutta-percha points (Tanariman, Manucapuru, Brazil), and size R7 accessory points (Tanariman, Manucapuru, Brazil), and AHPlus sealer (Dentsply, Petrópolis, Brazil). The filling material excess was removed with the aid of heated plugger.

Then, the teeth were sealed with a provisional restorative material (Cavit, Premier, Norristown, USA). Radiographs were taken at buccal-lingual direction to observe whether the canals were completely filled and well-condensed. Next, the specimens were kept in an incubator at 37°C, in humidity, for 30 days.

Elapsed that period, the specimens were randomly distributed into four groups (n=15) according to the retreatment technique: group I (control) – manual removal with the aid of K files (Dentsply-Maillefer, Ballaigues, Switzerland) at descending order from size #80 to #25, ending with size #30 to #40, associated with solvent (eucalyptol, S.S.White, Rio de Janeiro, Brazil); group II – manual removal, as described in group I, and associated with size 3 and 4 Gates-Glidden drills at medium and cervical thirds and solvent; group III – Protaper Universal System, with sequence of D1, D2, and D3 files coupled to X-Smart motor (Dentsply-Maillefer, Ballaigues, Switzerland) at crosshead speed of 300 rpm and torque of 4.0 N; and group IV – Protaper Universal System (Dentsply-Maillefer, Ballaigues, Switzerland), with sequence from F1 to F5, motor-driven (X-Smart motor, Dentsply-Maillefer, Ballaigues, Switzerland), at crosshead speed of 400 rpm and torque of 4.0 N, and use of solvent.

We considered the complete material removal when the instrument did not show material remnants outside root canal. The desobturation time of each specimen was obtained with the aid of a stopwatch.

Groves were vertically made on all roots at buccal-lingual direction with the aid of ¼ Carbide drill (JET, Beavers Dental, Canada), by preserving the root canal space. With the aid of chisel and hammer, the roots were cross-sectional sectioned.

The root canal walls were visually evaluated by a previously calibrated examiner. The presence of filling material was assessed through the following scores: 0 – without remnant, 1 – presence of only cement, 2 – presence of cement and gutta-percha in small amounts, and 3 – presence of cement and gutta-percha in large amounts.

The results were recorded, tabulated, and analyzed through GraphPad InStat software. Firstly, data were submitted to descriptive analysis and because of nonparametric distribution, Kruskal-Wallis test was adopted, followed by Dunn's Multiple test.



Assessment of filling remnant

The score means are seen in table 1.




There were no statistically significant differences among the groups tested (p > 0.05).

Assessment of the time required for root canal desobturation

Table 2 displays the time period means (seconds).




Also, there were no statistically significant differences among the groups tested (p > 0.05).

Concerning to the differences among groups, the results evidenced that group II obtained the shortest time (199 s), with statistically significant differences in relation to groups I and IV, with the highest time periods, 431 s and 455 s, respectively.

Group III obtained an intermediate type, 291 s, with statistically significant difference in relation to group IV.



The therapy of first choice for endodontic treatment failure is endodontic retreatment, whose goal is the complete removal of the filling material from all root canal extension, making easy both the cleaning and shaping 2,3,5,9,17,18,20,23,27.

Although endodontic retreatment is common in dental practice, some techniques and materials make difficult the removal of the filling material, leading to the searching for faster, safer and more effective resources, which undoubtedly, results in success 2,3,5,9,11,17,18,20,23,27,28.

The most common filling material to be removed is gutta-percha 13,14. For this purpose, either hand or rotary instruments, with or without solvents, can be used 9,13,18,20.

Concerning to rotary instruments, Protaper Retreatment System has instruments with active point enabling the filling material removal without using solvents, eliminating the formation of a gutta-percha film on root canal walls, which could prevent the action of intracanal medication on root canal disinfection process during endodontic retreatment 13. It is noteworthy to mention that some authors do not considered this additional procedure as essential for seeking a better disinfection 10.

On the other hand, Protaper Universal System does not have instruments with active point, and consequently, in this present study, it was employed together with solvents, aiming at favoring the penetration of the instruments.

The rationale for the choice of mandibular pre-molars was based on previous studies using the same teeth 12,13,19,26,28. Both the execution by one examiner and the storage conditions followed the same guidelines of previous researches that justified those strategies as important and close to real conditions 19.

Concerning to the time period required for filling material setting, the literature shows lack of consensus with periods ranging from 14 days 19 to one year 5. In this present study, we chose a period of 30 days. Both the removal of the coronal portion 34, the longitudinal cleavage of the teeth 12,19, and the visual analysis of the filling material remnant 1 were methodological options based on previous studies.

After the sample preparation and storage, endodontic retreatment was accomplished to evaluate the amount of both filling material remnant and time period for desobturation. We found that the faster desobturation technique (manual + Gates-Glidden + solvent) was not the most effective.

The literature does not reach a consensus on both the time and efficacy of desobturation techniques. The hand technique with the aid of either different instruments 3,19, ultrasound 7, or Gates-Glidden drills 19, has been considered as the fastest one. Also, in relation to efficacy, many studies have pointed out the advantages of this technique 3-5.

With the advent of rotary instruments, studies have been conducted on their performance during endodontic retreatments. Thus, some systems achieved expressive results in terms of cleaning efficacy and time period when compared with manual technique 5,11,12,24.

The use of solvents associated with rotary instrument has been discussed because of some contraindications of its use 14. However, many comparisons have been conducted among different rotary systems associated with the solvent. According to Hülsmann and Bluhm 18, Protaper System associated with eucalyptol was the fastest technique, while o Flex Master System associated with eucalyptol was the most effective technique in removing the filling material. Schirrmeister et al. 28 compared the manual technique associated with Gates-Glidden drills with three rotary systems also associated with drills and identified that RaCe System presented the best result, in relation to both the cleaning of the root canal walls and the time period required for desobturation.

In this present study, the group that obtained the best cleaning scores was that using Protaper Universal System, corroborating the findings of Saad et al. 26, who employed Protaper System, K3 System and manual technique. Conversely, the results of Unal et al. 32 showed that manual instrumentation was the most effective than Protaper System, although there were no statistically significant differences. Similarly, Zuolo et al. 35 pointed out the greatest cleaning capacity of root canal walls after the use of hand files associated with Gates-Glidden drills.

By comparing this study with researches employing similar methods, regarding to the time period required for removing the filling material, the group using manual + Gates-Glidden technique was faster, disagreeing with the study of Takahashi et al. 30. These authors compared manual files + Gates-Glidden drills with Protaper Retreatment System, with or without the use of solvent, and concluded that rotary system without solvent was the fastest technique. Bramante et al. 6, studying two rotary systems and comparing them with manual technique, indicated that Protaper Retreatment System had the best performance, corroborating the findings of Vale et al. 33. In this present study, Protaper Universal System was the slowest technique, contradicting the results of Hülsmann and Bluhm 18, who compared different rotary systems with manual instrumentation for desobturation and concluded that Protaper System associated with eucalyptol was the fastest technique.

The rationale behind the fastest manual technique employed in this study is the fact that the solvent dissolves the gutta-percha and the oval-shaped design of the Gates-Glidden drill, which favors the cutting and reduces the resistance of the filing material by the heating generated by the friction of the drill that plasticizes the gutta-percha.

It is believed that Protaper Universal System was more effective in the cleaning of root canals because of the association of the solvent with the instrument rotation, which causes the dilution and plasticization of gutta-percha. Still, the design of these instruments, according to the manufacturer's instructions, makes easy the removal of the filling material, because of the tendency of the gutta-percha to be pulled towards coronal direction 24.

A general analysis of the results regarding to the retreatment time differed from most of the previous studies reporting that rotary instruments were faster in removing the filling material. The possible physical characteristics of Gates-Glidden drills associated with the use of solvent and the manual control of the instrument may have led to the results found by this present study. Finally, it is noteworthy to mention that none procedure promoted the complete removal of the filling material, fact that has been identified by other studies 25,33,34.



There were no statistically significant differences among the techniques in relation to the time period and efficacy in removing the filling material from root canal walls.



1. Baratto-Filho F, Ferreira EL, Fariniuk LF. Efficiency of the 0.04 taper ProFile during the re-treatment of gutta-percha-filled root canals. Int Endod J. 2002;35(8):651-4.         [ Links ]

2. Barletta FB, Rahde NM, Limongi O, Moura AA, Zanesco C, Mazocatto G. In vitro comparative analysis of 2 mechanical techniques for removing gutta-percha during retreatment. J Can Dent Assoc. 2007;73(1):65.

3. Barrieshi-Nusair KM. Gutta-percha retreatment: effectiveness of nickel-titanium rotary instruments versus stainless steel hand files. J Endod. 2002;28(6):454-6.

4. Betti LV, Bramante CM, Moraes IG, Bernardinelli N, Garcia RB. Efficacy of Profile .04 taper series 29 in removing filling materials during root canal retreatment – an in vitro study. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2009;108(6):e46-50.

5. Betti LV, Bramante CM. Quantec SC rotary instruments versus hand files for gutta-percha removal in root canal retreatment. Int Endod J. 2001;34(7):514-9.

6. Bramante CM, Fidelis NS, Assumpção TS, Bernardinelli N, Garcia RB, Bramante AS et al. Heat release, time required, and cleaning ability of MTwo R and ProTaper universal retreatment systems in the removal of filling material. J Endod. 2010;36(11):1870-3.

7. Bramante CM, Freitas CVJ. Retratamento endodôntico: estudo comparativo entre técnica manual, ultra-som e Canal Finder. Rev Odontol Univ São Paulo. 1998;12(1):13-7.

8. Bueno CES, Delboni MG, Araújo RA, Carrara HJ, Cunha RS. Effectiveness of rotary and hand files in gutta-percha and sealer removal using chloroform or chloroform or chlorhexidine gel. Braz Dent J. 2006;17(2):139-43.

9. Duarte MAH, Só MVR, Cimadon VB, Zucatto C, Vier-Pelisser FV, Kuga MC. Effectiveness of rotary or manual techniques for removing a 6-year-old filling material. Braz Dent J. 2010;21(2):148-52.

10. Endo MS, Ferraz CC, Zaia AA, Almeida JF, Gomes BP. Quantitative and qualitative analysis of microorganisms in root-filled teeth with persistent infection: monitoring of the endodontic retreatment. Eur J Dent. 2013;7(3):302-9.

11. Ersev H, Yilmaz B, Dinçol ME, Dağlaroğlu R. The efficacy of ProTaper Universal rotary retreatment instrumentation to remove single gutta-percha cones cemented with several endodontic sealers. Int Endod J. 2012;45(8):756-62.

12. Fariniuk LF, Westphalen VP, Silva-Neto UX, Carneiro E, Baratto-Filho F, Fidel SR et al. Efficacy of five rotary systems versus manual instrumentation during endodontic retreatment. Braz Dent J. 2011;22(4):294-8.

13. Garcia-Júnior JS, Silva Neto UX, Carneiro E, Westphalen VPD, Fariniuk LF, Fidel RAS et al. Avaliação radiográfica da eficiência de diferentes instrumentos rotatórios no retratamento endodôntico. RSBO. 2008;5(2):41-9.

14. Good ML, McCammon A. A removal of gutta-percha and root canal sealer: a literature review and an audit comparing current practice in dental schools. Dent Update. 2012;39(10):703-8.

15. Hammad M, Qualtrough A, Silikas N. Three-dimensional evaluation of effectiveness of hand and rotary instruments for retreatment of canals filled with different materials. J Endod. 2008;34(11):1370-3.

16. Hayakawa T, Tomita F, Okiji T. Influence of the diameter and taper of root canals on the removal efficiency of Thermafil Plus plastic carriers using ProTaper retreatment files. J Endod. 2010;36(10):1676-8.

17. Huang X, Ling J, Gu L. Quantitative evaluation of debris extruded apically by using Protaper Universal Tulsa rotary system in endodontic retreatment. J Endod. 2007;33(9):1102-5.

18. Hülsmann M, Bluhm V. Efficacy, cleaning ability and safety of different rotary NiTi instruments in root canal retreatment. Int Endod J. 2004;37(7):468-76.

19. Imura N, Kato A, Hata GI, Uemura M, Toda T, Weine F. A comparison of the relative efficacies of four hand and rotary instrumentation techniques during endodontic retreatment. Int Endod J. 2000;33(4):361-6.

20. Kaled GH, Faria MIA, Heck AR, Aragão EM, Moares SH, Souza RC. Retratamento endodôntico: análise comparativa da efetividade da remoção da obturação dos canais radiculares realizada por três métodos. RGO. 2011;59(1):103-8.

21. Müller GG, Schönhofen ÂP, Móra PM, Grecca FS, Só MV, Bodanezi A. Efficacy of an organic solvent and ultrasound for filling material removal. Braz Dent J. 2013;24(6):585-90.

22. Naito T. Surgical or nonsurgical treatment for teeth with existing root fillings? Evid Based Dent. 2010;11(2):54-5.

23. Oliveira DP, Barbizam JVB, Trope M, Teixeira FB. Comparison between gutta-percha and Resilon removal using two techniques in endodontic retreatment. J Endod. 2006;32(4):362-4.

24. Reddy N, Admala SR, Dinapadu S, Pasari S, Reddy MP, Rao MS. Comparative analysis of efficacy and cleaning ability of hand and rotary devices for gutta-percha removal in root canal retreatment: an in vitro study. J Contemp Dent Pract. 2013;14(4):635-43.

25. Rios MA, Villela AM, Cunha RS, Velasco RC, De Martin AS, Kato AS et al. Efficacy of 2 reciprocating systems compared with a rotary retreatment system for gutta-percha removal. J Endod. 2014;40(4):543-6.

26. Saad AY, Al-Hadlaq SM, Al-Katheeri NH. Efficacy of two rotary NiTi instruments in the removal of gutta-percha during root canal retreatment. J Endod. 2007;33(1):38-41.

27. Sae-Lim V, Rajamanickam I, Lim BK, Lee HL. Effectiveness of ProFile .04 taper rotary instruments in endodontic retreatment. J Endod. 2000;26(2):100-4.

28. Schirrmeister JF, Wrbas KT, Meyer KM, Altenburger MJ, Hellwig E. Efficacy of different rotary instruments for gutta-percha removal in root canal retreatment. J Endod. 2006;32(5):469-72.

29. Tagger M, Tamse A, Katz A, Korzen BH. Evaluation of the apical seal produced by a hybrid root canal filling method, combining lateral condensation and thermatic compaction. J Endod. 1984;10(7):299-303.

30. Takahashi CM, Cunha RS, de Martin AS, Fontana CE, Silveira CF, Silveira Bueno CE. In vitro evaluation of the effectiveness of ProTaper universal rotary retreatment system for gutta-percha removal with or without a solvent. J Endod. 2009;35(11):1580-3.

31. Torabinejad M, Corr R, Handysides R, Shabahang S. Outcomes of nonsurgical retreatment and endodontic surgery: a systematic review. J Endod. 2009;35(7):930-7.

32. Unal GC, Kaya BU, Taç AG, Keçeci AD. A comparison of the efficacy of conventional and new retreatment instruments to remove gutta-percha in curved root canals: an ex vivo study. Int Endod J. 2009;42(4):344-50.

33. Vale MS, Moreno MS, Silva PM, Botelho TC. Endodontic filling removal procedure: an ex vivo comparative study between two rotary techniques. Braz Oral Res. 2013;27(6):478-83.

34. Yadav P, Bharath MJ, Sahadev CK, Makonahalli Ramachandra PK, Rao Y, Ali A et al. An in vitro CT comparison of gutta-percha removal with two rotary systems and Hedstrom files. Iran Endod J. 2013;8(2):59-64.

35. Zuolo AS, Mello Jr JE, Cunha RS, Zuolo ML, Bueno CE. Efficacy of reciprocating and rotary techniques for removing filling material during root canal retreatment. Int Endod J. 2013;46(10):947-53.



Corresponding author:
Maria Isabel Anastácio Faria
Rua Visconde de Nacar, n. 865, cj. 1.007
CEP 80410-904 – Curitiba – PR – Brasil



Received for publication: June 30, 2014
Accepted for publication: July 22, 2014