Basic Research—Technology
Reciprocating Versus Rotary Systems for Root Filling Removal: Assessment of the Apically Extruded Material Emmanuel Jo~ ao Nogueira Leal Silva, DDS, MSc, PhD,* Liliane S a, DDS,* Felipe Gonc¸alves Belladonna, DDS, MSc,* Aline A. Neves, DDS, MSc, PhD,† Thais Accorsi-Mendonc¸a, DDS, MSc, PhD,* Victor T.L. Vieira, DDS, MSc, PhD,* Gustavo De-Deus, DDS, MSc, PhD,* and Edson J. Moreira, DDS, MSc, PhD* Abstract Introduction: This study was designed to quantitatively evaluate the amount of apically extruded debris by comparing the ProTaper Universal Retreatment system (Dentsply Maillefer, Ballaigues, Switzerland) with 2 reciprocating single-file systems (Reciproc [VDW, Munich, Germany] and WaveOne [Dentsply Maillefer]) during endodontic retreatment. Methods: Forty-five mandibular premolars with a single canal were prepared with the ProTaper Universal system and then obturated. The specimens were divided into 3 groups (n = 15) according to the system used for filling removal: ProTaper Universal Retreatment system associated with the ProTaper Universal system (until file F4 40/0.06]), Reciproc system (Reciproc R40 [40/0.06]), and WaveOne system (WaveOne Large [40/0.08]). Sodium hypochlorite was used as an irrigant, and the apically extruded debris was collected in glass vials and then dried. The mean weight of debris was assessed with a microbalance and statistically analyzed using 1-way analysis of variance and post hoc Tukey multiple comparison tests (P < .05). Results: The ProTaper Universal Retreatment system produced significantly more debris compared with the Reciproc and WaveOne systems (P < .01). The reciprocating systems showed no significant difference between them (P > .05). Conclusions: Under the conditions of the present study, all systems caused apical debris extrusion. Reciprocating systems were associated with less debris extrusion when compared with a conventional rotary retreatment system. (J Endod 2014;40:2077–2080)
Key Words Debris extrusion, nickel-titanium, reciprocating motion, root canal retreatment From the *Department of Endodontics, School of Dentistry – Grande Rio University (UNIGRANRIO); and †Department of Pediatric Dentistry and Orthodontics, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil. Address requests for reprints to Dr Emmanuel Jo~ao Nogueira Leal da Silva, Endodontics Department, Dental School–Grande Rio University (UNIGRANRIO), Rua Herotides de Oliveira, 61/902, Icaraı, Niteroi, RJ, Brazil. E-mail address: [email protected] 0099-2399/$ - see front matter Copyright ª 2014 American Association of Endodontists. http://dx.doi.org/10.1016/j.joen.2014.09.009
JOE — Volume 40, Number 12, December 2014
D
uring root canal retreatment procedures, aggressive materials and their products, such as dentin chips, microorganisms and their byproducts, remaining pulp tissue, root filling material, and irrigants usually extrude into the periradicular tissues. The apical extrusion phenomenon is an undesirable side effect of the shaping procedures that may induce inflammation, postoperative pain, and delay of periapical healing (1–3). Currently, all preparation techniques and instruments are, at least to some degree, associated with extrusion of debris; however, there are major differences among these techniques. It is worthwhile to note that, although apical extrusion of dentinal debris and irrigants has been observed with the use of all currently used root canal preparation techniques and instruments, less dentinal debris extrusion has been associated with the use of motor-driven rotary instruments (4–7). The recent introduction of 2 reciprocation-based systems (Reciproc [VDW, Munich, Germany] and WaveOne [Dentsply Maillefer, Ballaigues, Switzerland]) onto the market has raised new perspectives for root canal preparation, and, to some extent, there are reports showing that they have outperformed conventional continuous rotary nickel-titanium (NiTi) preparation in some aspects. The reciprocating motion relieves the stress on the instrument by special counterclockwise (cutting action) and clockwise (release of the instrument) movements and, therefore, extends the durability of a NiTi instrument and increases its resistance to fatigue in comparison with continuous rotation motion (8, 9). Although reciprocating systems were not originally designed to remove root filling materials, the assumption that their use can be an effective approach is supported by the high ability of the reciprocating movement in advancing toward the apex (10). Moreover, no doubt exists that, under a cost-effective perspective, the use of only 1 NiTi instrument is advantageous over conventional multifile systems, and the learning curve can be reduced by the simplification of the technical procedure. Two recent studies showed that single-file reciprocating techniques were as effective as multifile retreatment rotary systems for gutta-percha and sealer removal but in a faster way (11, 12). Nonetheless, the continuous research and clinical usage of reciprocating systems for root canal retreatment has brought some concerns, such as the amount of dentin chips, irrigants, remaining pulp tissue, bacteria, and their byproducts that may be extruded into the periradicular tissues (6, 7). To the best of the authors’ knowledge, there is no reliable evidence on the amount of debris extrusion during endodontic retreatment using reciprocation-based systems. Therefore, the present study was designed to evaluate the amount of apically extruded debris produced by 2 single-file reciprocating systems (Reciproc and WaveOne) during endodontic retreatment. The ProTaper Universal Retreatment system (Dentsply Maillefer) was used as the reference technique for comparison. The null hypothesis tested was that there are no significant differences on the amount of debris extruded among the 3 tested systems.
Materials and Methods Sample Selection This study was revised and approved by the local ethics committee. A sample of 45 human mandibular premolars with a single canal and similar root length were collected. Soft tissue remnants and calculus on the external root surface were
Debris Extrusion During Retreatment
2077
Basic Research—Technology mechanically removed. The teeth were disinfected in 0.5% chloramine T, stored in distilled water at 4 C, and used within 6 months after extraction. Root canal curvature was determined based on the angle of curvature initiated at the coronal aspect of the apical third of the root using Schneider’s method (13). After acquiring digital images of the sample, the angle of curvature of each specimen was measured using an image analysis program (AxioVision 4.5; Carl Zeiss Vision, Hallbergmoos, Germany). Only teeth with root curvature .05).
Discussion The present results showed that apical debris extrusion occurred regardless of the retreatment system used. The ProTaper Universal Retreatment system produced significantly more debris than both reciprocating systems (P < .01). Therefore, the null hypothesis was rejected. The general amount of apically extruded debris produced by the ProTaper Universal Retreatment system was already known from the literature (15–17); however, to the best of the authors’ knowledge, there are no data on apical debris extrusion using Reciproc and WaveOne files as retreatment systems. Results presented herein may be explained by the differences in instrument design, the number of files used, and movement kinematics among the systems. The ProTaper Universal Retreatment group used 6 files for root filling removal, whereas the Reciproc and WaveOne groups used only 2 files (R25 and R40 for Reciproc and WaveOne PriJOE — Volume 40, Number 12, December 2014
mary and Large for WaveOne). However, the ProTaper Universal Retreatment system consists of 3 files, as suggested in previous studies (7, 12). Further root canal refining is necessary because of the apical diameter of the D3 file (size 20), which does not allow a reasonable cleaning of the apical root canal portion. In the present study, ProTaper F2, F3, and F4 files were used to complete the root canal cleaning of the ProTaper Universal Retreatment system. To create standardized experimental conditions allowing a direct comparison and to promote an apical enlargement, Reciproc R40 and WaveOne Large files were used after Reciproc R25 and WaveOne Primary files, respectively. Therefore, apical enlargement up to a final size #40 was performed in all tested groups because previous investigations have backed up that apical enlargement by 2 sizes beyond the initial preparation size significantly reduced the amount of residual filling material (18, 19). No statistically significant differences were observed between the Reciproc and WaveOne systems (P > .05). Although WaveOne has a bigger core mass than Reciproc, this result may be explained by some similarities between them, such as the driven under reciprocating movement and the same alloy and tip size (20). It is important to emphasize that the improved control of apically extruded debris promoted by both reciprocating systems during root filling removal found in the present study are, at least to some extent, in line with recent studies that have shown better control during primary root canal treatment (6, 21). The amount of extruded debris was collected following the Myers and Montgomery method (14), but the collection apparatus was slightly modified to make it more simple, practical, and affordable as previously suggested (6, 22). Moreover, this method eliminated the possibility of fingertip contamination throughout the entire experiment procedure because there was no direct contact between the operator’s fingertips and the assembly (6). It is worth mentioning that because the amount of extruded material is extremely low, the contact of moist or greasy fingertips may alter the weight of extruded debris significantly (22). Caution should be taken when extrapolating the current results to the clinical situation because the in vitro setup used in this study had the apex suspended in the air without any physical back pressure, whereas, in vivo, the apex would be surrounded by granulomatous or periradicular tissues, which could limit apical extrusion (15, 23). This is an imminent shortcoming of in vitro designs with no periapical resistance, as already discussed by Myers and Montgomery
Debris Extrusion During Retreatment
2079
Basic Research—Technology (14). The use of floral foam to simulate the resistance of periapical tissues has been suggested recently (24, 25). However, this approach may absorb irrigant solution and debris when used as a barrier. Therefore, no attempt has been made to simulate periapical resistance in the present study (7). Under the experimental conditions of the present study, it can be concluded that all retreatment systems caused apical debris extrusion. Reciprocating systems were associated with less debris extrusion when compared with a conventional rotary retreatment system.
Acknowledgments Supported by the Fundac¸~ao de Amparo a Pesquisa do Estado do Rio de Janeiro (FAPERJ) grant no. E-26/111.264/2013. The authors deny any conflicts of interest related to this study.
References 1. Seltzer S, Naidorf IJ. Flare-ups in endodontics: I. Etiological factors. J Endod 1985; 11:472–8. 2. Seltzer S, Naidorf IJ. Flare-ups in endodontics: II. Therapeutic measures. J Endod 1985;11:559–67. 3. Siqueira JF Jr, R^oc¸as IN, Favieri A, et al. Incidence of postoperative pain after intracanal procedures based on an antimicrobial strategy. J Endod 2002;28:457–60. 4. Beeson TJ, Hartwell GR, Thornton JD, et al. Comparison of debris extruded apically in straight canals: conventional filing versus Profile .04 taper series 29. J Endod 1998;24:18–22. 5. Ferraz CC, Gomes NV, Gomes BP, et al. Apical extrusion of debris and irrigants using two hands and three engine-driven instrumentation techniques. Int Endod J 2001; 34:354–8. 6. De-Deus G, Brand~ao MC, Barino B, et al. Assessment of apically extruded debris produced by the single-file ProTaper F2 technique under reciprocating movement. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2010;110:390–4. 7. B€urklein S, Sch€afer E. Apically extruded debris with reciprocating single-file and full-sequence rotary instrumentation systems. J Endod 2012;38:850–2. 8. Yared G. Canal preparation using only one Ni-Ti rotatory instrument: preliminary observations. Int Endod J 2008;41:339–44. 9. Varela-Pati~no P, Iba~nez-Parraga A, Rivas-Mundi~na B, et al. Alternating versus continuous rotation: a comparative study of the effect on instrument life. J Endod 2010;36:157–9.
2080
Silva et al.
10. De-Deus G, Arruda TEP, Souza EM, et al. The ability of the Reciproc R25 instrument to reach the full root canal working length without a glided path. Int Endod J 2013; 46:993–8. 11. Zuolo AS, Mello JE Jr, Cunha RS, et al. Efficacy of reciprocating and rotary techniques for removing filling material during root canal retreatment. Int Endod J 2013;46:947–53. 12. Rios MA, Villela AM, Cunha RS, et al. Efficacy of 2 reciprocating systems compared with a rotary retreatment system for gutta-percha removal. J Endod 2014;40:543–6. 13. Schneider SW. A comparison of canal preparations in straight and curved root canals. Oral Surg Oral Med Oral Path Oral Radiol Endod 1971;2:271–5. 14. Myers GL, Montgomery S. A comparison of weights of debris extruded apically by conventional filling and Canal Master techniques. J Endod 1991;17:275–9. 15. Huang X, Ling J, Wei X, et al. Quantitative evaluation of debris extruded apically by using ProTaper Universal Tulsa rotary system in endodontic retreatment. J Endod 2007;33:1102–5. 16. Kustarci A, Altunbas D, Akpinar KE. Comparative study of apically extruded debris using one manual and two rotary instrumentation technique for endodontic retreatment. J Dent Sci 2012;7:1–6. 17. Uezu MKN, Britto MLB, Nabeshima CK, et al. Comparison of debris extruded apically and working time used by ProTaper Universal rotary and ProTaper retreatment system during gutta-percha removal. J Appl Oral Sci 2010;18:542–5. 18. Friedman S. Management of post-treatment endodontic disease—a current concept of case selection. Aust Endod J 2000;23:104–9. 19. 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;35:651–4. 20. You SY, Kim HC, Bae KS, et al. Shaping ability of reciprocating motion in curved root canals: a comparative study with micro-computed tomography. J Endod 2011;37: 1296–300. 21. Tinoco JM, De-Deus G, Tinoco EM, et al. Apical extrusion of bacteria when using reciprocating single-file and rotary multifile instrumentation systems. Int Endod J 2014;47:560–6. 22. De-Deus GA, Silva EJNL, Moreira EJ, et al. Assessment of apically extruded debris produced by the Self-Adjusting File system. J Endod 2014;40:526–9. 23. Salzgeber RM, Brilliant JD. An in vivo evaluation of the penetration of an irrigating solution in root canals. J Endod 1977;3:394–8. 24. Hachmeister DR, Schindler WG, Walker WA, et al. The sealing ability and retention characteristics of mineral trioxide aggregate in a model of apexification. J Endod 2002;28:386–90. 25. Altundasar E, Nagas E, Uyanik O, et al. Debris and irrigant extrusion potential of 2 rotary systems and irrigation needles. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2011;112:e31–5.
JOE — Volume 40, Number 12, December 2014
Reciprocating Versus Rotary Systems for Root Filling Removal: Assessment of the Apically Extruded Material Emmanuel Jo~ ao Nogueira Leal Silva, DDS, MSc, PhD,* Liliane S a, DDS,* Felipe Gonc¸alves Belladonna, DDS, MSc,* Aline A. Neves, DDS, MSc, PhD,† Thais Accorsi-Mendonc¸a, DDS, MSc, PhD,* Victor T.L. Vieira, DDS, MSc, PhD,* Gustavo De-Deus, DDS, MSc, PhD,* and Edson J. Moreira, DDS, MSc, PhD* Abstract Introduction: This study was designed to quantitatively evaluate the amount of apically extruded debris by comparing the ProTaper Universal Retreatment system (Dentsply Maillefer, Ballaigues, Switzerland) with 2 reciprocating single-file systems (Reciproc [VDW, Munich, Germany] and WaveOne [Dentsply Maillefer]) during endodontic retreatment. Methods: Forty-five mandibular premolars with a single canal were prepared with the ProTaper Universal system and then obturated. The specimens were divided into 3 groups (n = 15) according to the system used for filling removal: ProTaper Universal Retreatment system associated with the ProTaper Universal system (until file F4 40/0.06]), Reciproc system (Reciproc R40 [40/0.06]), and WaveOne system (WaveOne Large [40/0.08]). Sodium hypochlorite was used as an irrigant, and the apically extruded debris was collected in glass vials and then dried. The mean weight of debris was assessed with a microbalance and statistically analyzed using 1-way analysis of variance and post hoc Tukey multiple comparison tests (P < .05). Results: The ProTaper Universal Retreatment system produced significantly more debris compared with the Reciproc and WaveOne systems (P < .01). The reciprocating systems showed no significant difference between them (P > .05). Conclusions: Under the conditions of the present study, all systems caused apical debris extrusion. Reciprocating systems were associated with less debris extrusion when compared with a conventional rotary retreatment system. (J Endod 2014;40:2077–2080)
Key Words Debris extrusion, nickel-titanium, reciprocating motion, root canal retreatment From the *Department of Endodontics, School of Dentistry – Grande Rio University (UNIGRANRIO); and †Department of Pediatric Dentistry and Orthodontics, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil. Address requests for reprints to Dr Emmanuel Jo~ao Nogueira Leal da Silva, Endodontics Department, Dental School–Grande Rio University (UNIGRANRIO), Rua Herotides de Oliveira, 61/902, Icaraı, Niteroi, RJ, Brazil. E-mail address: [email protected] 0099-2399/$ - see front matter Copyright ª 2014 American Association of Endodontists. http://dx.doi.org/10.1016/j.joen.2014.09.009
JOE — Volume 40, Number 12, December 2014
D
uring root canal retreatment procedures, aggressive materials and their products, such as dentin chips, microorganisms and their byproducts, remaining pulp tissue, root filling material, and irrigants usually extrude into the periradicular tissues. The apical extrusion phenomenon is an undesirable side effect of the shaping procedures that may induce inflammation, postoperative pain, and delay of periapical healing (1–3). Currently, all preparation techniques and instruments are, at least to some degree, associated with extrusion of debris; however, there are major differences among these techniques. It is worthwhile to note that, although apical extrusion of dentinal debris and irrigants has been observed with the use of all currently used root canal preparation techniques and instruments, less dentinal debris extrusion has been associated with the use of motor-driven rotary instruments (4–7). The recent introduction of 2 reciprocation-based systems (Reciproc [VDW, Munich, Germany] and WaveOne [Dentsply Maillefer, Ballaigues, Switzerland]) onto the market has raised new perspectives for root canal preparation, and, to some extent, there are reports showing that they have outperformed conventional continuous rotary nickel-titanium (NiTi) preparation in some aspects. The reciprocating motion relieves the stress on the instrument by special counterclockwise (cutting action) and clockwise (release of the instrument) movements and, therefore, extends the durability of a NiTi instrument and increases its resistance to fatigue in comparison with continuous rotation motion (8, 9). Although reciprocating systems were not originally designed to remove root filling materials, the assumption that their use can be an effective approach is supported by the high ability of the reciprocating movement in advancing toward the apex (10). Moreover, no doubt exists that, under a cost-effective perspective, the use of only 1 NiTi instrument is advantageous over conventional multifile systems, and the learning curve can be reduced by the simplification of the technical procedure. Two recent studies showed that single-file reciprocating techniques were as effective as multifile retreatment rotary systems for gutta-percha and sealer removal but in a faster way (11, 12). Nonetheless, the continuous research and clinical usage of reciprocating systems for root canal retreatment has brought some concerns, such as the amount of dentin chips, irrigants, remaining pulp tissue, bacteria, and their byproducts that may be extruded into the periradicular tissues (6, 7). To the best of the authors’ knowledge, there is no reliable evidence on the amount of debris extrusion during endodontic retreatment using reciprocation-based systems. Therefore, the present study was designed to evaluate the amount of apically extruded debris produced by 2 single-file reciprocating systems (Reciproc and WaveOne) during endodontic retreatment. The ProTaper Universal Retreatment system (Dentsply Maillefer) was used as the reference technique for comparison. The null hypothesis tested was that there are no significant differences on the amount of debris extruded among the 3 tested systems.
Materials and Methods Sample Selection This study was revised and approved by the local ethics committee. A sample of 45 human mandibular premolars with a single canal and similar root length were collected. Soft tissue remnants and calculus on the external root surface were
Debris Extrusion During Retreatment
2077
Basic Research—Technology mechanically removed. The teeth were disinfected in 0.5% chloramine T, stored in distilled water at 4 C, and used within 6 months after extraction. Root canal curvature was determined based on the angle of curvature initiated at the coronal aspect of the apical third of the root using Schneider’s method (13). After acquiring digital images of the sample, the angle of curvature of each specimen was measured using an image analysis program (AxioVision 4.5; Carl Zeiss Vision, Hallbergmoos, Germany). Only teeth with root curvature .05).
Discussion The present results showed that apical debris extrusion occurred regardless of the retreatment system used. The ProTaper Universal Retreatment system produced significantly more debris than both reciprocating systems (P < .01). Therefore, the null hypothesis was rejected. The general amount of apically extruded debris produced by the ProTaper Universal Retreatment system was already known from the literature (15–17); however, to the best of the authors’ knowledge, there are no data on apical debris extrusion using Reciproc and WaveOne files as retreatment systems. Results presented herein may be explained by the differences in instrument design, the number of files used, and movement kinematics among the systems. The ProTaper Universal Retreatment group used 6 files for root filling removal, whereas the Reciproc and WaveOne groups used only 2 files (R25 and R40 for Reciproc and WaveOne PriJOE — Volume 40, Number 12, December 2014
mary and Large for WaveOne). However, the ProTaper Universal Retreatment system consists of 3 files, as suggested in previous studies (7, 12). Further root canal refining is necessary because of the apical diameter of the D3 file (size 20), which does not allow a reasonable cleaning of the apical root canal portion. In the present study, ProTaper F2, F3, and F4 files were used to complete the root canal cleaning of the ProTaper Universal Retreatment system. To create standardized experimental conditions allowing a direct comparison and to promote an apical enlargement, Reciproc R40 and WaveOne Large files were used after Reciproc R25 and WaveOne Primary files, respectively. Therefore, apical enlargement up to a final size #40 was performed in all tested groups because previous investigations have backed up that apical enlargement by 2 sizes beyond the initial preparation size significantly reduced the amount of residual filling material (18, 19). No statistically significant differences were observed between the Reciproc and WaveOne systems (P > .05). Although WaveOne has a bigger core mass than Reciproc, this result may be explained by some similarities between them, such as the driven under reciprocating movement and the same alloy and tip size (20). It is important to emphasize that the improved control of apically extruded debris promoted by both reciprocating systems during root filling removal found in the present study are, at least to some extent, in line with recent studies that have shown better control during primary root canal treatment (6, 21). The amount of extruded debris was collected following the Myers and Montgomery method (14), but the collection apparatus was slightly modified to make it more simple, practical, and affordable as previously suggested (6, 22). Moreover, this method eliminated the possibility of fingertip contamination throughout the entire experiment procedure because there was no direct contact between the operator’s fingertips and the assembly (6). It is worth mentioning that because the amount of extruded material is extremely low, the contact of moist or greasy fingertips may alter the weight of extruded debris significantly (22). Caution should be taken when extrapolating the current results to the clinical situation because the in vitro setup used in this study had the apex suspended in the air without any physical back pressure, whereas, in vivo, the apex would be surrounded by granulomatous or periradicular tissues, which could limit apical extrusion (15, 23). This is an imminent shortcoming of in vitro designs with no periapical resistance, as already discussed by Myers and Montgomery
Debris Extrusion During Retreatment
2079
Basic Research—Technology (14). The use of floral foam to simulate the resistance of periapical tissues has been suggested recently (24, 25). However, this approach may absorb irrigant solution and debris when used as a barrier. Therefore, no attempt has been made to simulate periapical resistance in the present study (7). Under the experimental conditions of the present study, it can be concluded that all retreatment systems caused apical debris extrusion. Reciprocating systems were associated with less debris extrusion when compared with a conventional rotary retreatment system.
Acknowledgments Supported by the Fundac¸~ao de Amparo a Pesquisa do Estado do Rio de Janeiro (FAPERJ) grant no. E-26/111.264/2013. The authors deny any conflicts of interest related to this study.
References 1. Seltzer S, Naidorf IJ. Flare-ups in endodontics: I. Etiological factors. J Endod 1985; 11:472–8. 2. Seltzer S, Naidorf IJ. Flare-ups in endodontics: II. Therapeutic measures. J Endod 1985;11:559–67. 3. Siqueira JF Jr, R^oc¸as IN, Favieri A, et al. Incidence of postoperative pain after intracanal procedures based on an antimicrobial strategy. J Endod 2002;28:457–60. 4. Beeson TJ, Hartwell GR, Thornton JD, et al. Comparison of debris extruded apically in straight canals: conventional filing versus Profile .04 taper series 29. J Endod 1998;24:18–22. 5. Ferraz CC, Gomes NV, Gomes BP, et al. Apical extrusion of debris and irrigants using two hands and three engine-driven instrumentation techniques. Int Endod J 2001; 34:354–8. 6. De-Deus G, Brand~ao MC, Barino B, et al. Assessment of apically extruded debris produced by the single-file ProTaper F2 technique under reciprocating movement. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2010;110:390–4. 7. B€urklein S, Sch€afer E. Apically extruded debris with reciprocating single-file and full-sequence rotary instrumentation systems. J Endod 2012;38:850–2. 8. Yared G. Canal preparation using only one Ni-Ti rotatory instrument: preliminary observations. Int Endod J 2008;41:339–44. 9. Varela-Pati~no P, Iba~nez-Parraga A, Rivas-Mundi~na B, et al. Alternating versus continuous rotation: a comparative study of the effect on instrument life. J Endod 2010;36:157–9.
2080
Silva et al.
10. De-Deus G, Arruda TEP, Souza EM, et al. The ability of the Reciproc R25 instrument to reach the full root canal working length without a glided path. Int Endod J 2013; 46:993–8. 11. Zuolo AS, Mello JE Jr, Cunha RS, et al. Efficacy of reciprocating and rotary techniques for removing filling material during root canal retreatment. Int Endod J 2013;46:947–53. 12. Rios MA, Villela AM, Cunha RS, et al. Efficacy of 2 reciprocating systems compared with a rotary retreatment system for gutta-percha removal. J Endod 2014;40:543–6. 13. Schneider SW. A comparison of canal preparations in straight and curved root canals. Oral Surg Oral Med Oral Path Oral Radiol Endod 1971;2:271–5. 14. Myers GL, Montgomery S. A comparison of weights of debris extruded apically by conventional filling and Canal Master techniques. J Endod 1991;17:275–9. 15. Huang X, Ling J, Wei X, et al. Quantitative evaluation of debris extruded apically by using ProTaper Universal Tulsa rotary system in endodontic retreatment. J Endod 2007;33:1102–5. 16. Kustarci A, Altunbas D, Akpinar KE. Comparative study of apically extruded debris using one manual and two rotary instrumentation technique for endodontic retreatment. J Dent Sci 2012;7:1–6. 17. Uezu MKN, Britto MLB, Nabeshima CK, et al. Comparison of debris extruded apically and working time used by ProTaper Universal rotary and ProTaper retreatment system during gutta-percha removal. J Appl Oral Sci 2010;18:542–5. 18. Friedman S. Management of post-treatment endodontic disease—a current concept of case selection. Aust Endod J 2000;23:104–9. 19. 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;35:651–4. 20. You SY, Kim HC, Bae KS, et al. Shaping ability of reciprocating motion in curved root canals: a comparative study with micro-computed tomography. J Endod 2011;37: 1296–300. 21. Tinoco JM, De-Deus G, Tinoco EM, et al. Apical extrusion of bacteria when using reciprocating single-file and rotary multifile instrumentation systems. Int Endod J 2014;47:560–6. 22. De-Deus GA, Silva EJNL, Moreira EJ, et al. Assessment of apically extruded debris produced by the Self-Adjusting File system. J Endod 2014;40:526–9. 23. Salzgeber RM, Brilliant JD. An in vivo evaluation of the penetration of an irrigating solution in root canals. J Endod 1977;3:394–8. 24. Hachmeister DR, Schindler WG, Walker WA, et al. The sealing ability and retention characteristics of mineral trioxide aggregate in a model of apexification. J Endod 2002;28:386–90. 25. Altundasar E, Nagas E, Uyanik O, et al. Debris and irrigant extrusion potential of 2 rotary systems and irrigation needles. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2011;112:e31–5.
JOE — Volume 40, Number 12, December 2014
