doi:10.1111/iej.12449
Comparison of apically extruded debris after root canal instrumentation using Reciprocâ instruments with various kinematics
anay1, M. Alsancak1, I. D. C € ndu € z1 H. Arslan1, E. Dog ß apar2, E. Karatasß1 & H. A. Gu 1
Department of Endodontics, Faculty of Dentistry, Ataturk University, Erzurum; and 2Department of Endodontics, Faculty of _ Dentistry, Izmir Katip C Turkey ß elebi University, Izmir,
Abstract anay E, Alsancak M, C Arslan H, Dog ß apar ID, Karatasß € ndu € z HA. Comparison of apically extruded debris E, Gu after root canal instrumentation using Reciprocâ instruments with various kinematics. International Endodontic Journal.
Aim To assess the amount of apically extruded debris using Reciprocâ instruments with different kinematics (150° counter clockwise [CCW]–30° clockwise [CW], 270° CCW–30° CW, 360° CCW–30° CW and continuous rotation). Methodology Forty-eight maxillary central incisors were selected and assigned to four root canal shaping groups as follows (n = 12): 150° CCW–30° CW, 270° CCW–30° CW, 360° CCW–30° CW and continuous rotation. Reciproc R25 and R50â instruments were used in all groups. Apically extruded debris was collected and dried in preweighed Eppendorf tubes. The
Introduction During root canal preparation, irrigants, dentine chips, pulp tissue and microorganisms may be extruded into the periradicular tissues and cause postoperative pain and complications (Seltzer & Naidorf 1985). Studies examining the apical extrusion of debris have reported that all instrumentation techniques and instruments are associated with the extrusion of debris (Fairbourn et al. 1987, Er et al. 2005, Tinaz et al. 2005, Tanalp et al. 2006, Kustarci et al. 2008).
Correspondence: Hakan Arslan, Department of Endodontics, Faculty of Dentistry, Ataturk University, Erzurum 26240, Turkey (Tel.: +90.442.325 4040- 2352; Fax: +90.442.325 2535; e-mail: [email protected]).
© 2015 International Endodontic Journal. Published by John Wiley & Sons Ltd
weight of extruded debris was assessed with an electronic balance. The data were analysed with one way analysis of variance and LSD post hoc tests (P = 0.05). Results The 150° CCW–30° CW and 270° CCW– 30° CW reciprocating motions extruded significantly less debris than continuous rotation (P < 0.05). However, no significant differences were found between the 360° CCW and 30° CW reciprocating motion and the continuous rotation (P > 0.05). Conclusions All instrument movements were associated with apically extruded debris. However, the 150° CCW–30° CW and 270° CCW–30° CW reciprocating motions were associated with less extrusion than continuous rotation. Keywords: debris extrusion, kinematics, motion, movement, reciprocation, rotary. Received 9 December 2014; accepted 17 March 2015
There are conflicting reports on the effect of reciprocating and rotating instruments on the quantity of apically extruded debris (B€ urklein & Sch€ afer 2012, Kocak et al. 2013, B€ urklein et al. 2014, De-Deus et al. 2015, Tinoco et al. 2014). B€ urklein & Sch€ afer (2012) reported that full-sequence rotary instrumentation using Mtwo (VDW, Munich, Germany) and ProTaper (Dentsply Maillefer, Ballaigues, Switzerland) instruments was associated with less debris extrusion compared with the use of Reciproc (VDW) and WaveOne (Dentsply Maillefer) reciprocating single-file systems. Similarly, B€ urklein et al. (2014) found that rotary instrumentation using OneShape and multiple file Mtwo instruments was associated with less debris extrusion compared to reciprocating instrumentation (Reciproc). However, Kocak et al. (2013) found no
International Endodontic Journal
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Apically extruded debris, Reciproc, motion Arslan et al.
significant differences amongst single-file ProTaper F2 instruments, Revo-S SU instruments and Reciproc 25 instruments in terms of apically extruded debris. In contrast, Tinoco et al. (2014) found that WaveOne and Reciproc reciprocating single-file systems extruded fewer bacteria apically than a conventional multifile rotary system (BioRace; FKG Dentaire, La-Chaux-de-Fonds, Switzerland). Similarly, De-Deus et al. (2015) revealed that a conventional multifile rotary system (ProTaper) extruded significantly more debris than WaveOne and Reciproc. In previous reports, the single-file reciprocating instruments were compared with full-sequence instruments (B€ urklein & Sch€ afer 2012, B€ urklein et al. 2014). The use of different instruments and numbers of files could cause conflicting results, and it is not possible to segregate the influence of the reciprocal motion from these findings. There are no data in the literature related solely to the effect of root canal instrumentation using Reciprocâ instruments with different kinematics on the quantity of apically extruded debris. Therefore, the purpose of this laboratory study was to assess the amount of apically extruded debris using Reciprocâ instruments with different movements (150° counter clockwise [CCW]- 30° clockwise [CW], 270° CCW–30° CW, 360° CCW–30° CW and continuous rotation). The null hypothesis was that there would be no difference in weight of apically extruded debris amongst the groups.
Materials and methods The protocol of this study was approved by the Research Ethics Committee of Ataturk University, Erzurum, Turkey. Maxillary central incisors with similar lengths were selected from a collection of teeth that had been extracted for reasons unrelated to this study. Specimens were stored in 4 °C distilled water until use. Soft tissue and calculus were removed mechanically from the root surfaces with a periodontal scaler. The exclusion criteria were a tooth having more than one root canal and apical foramen, root canal treatment, internal/external resorption, immature root apices, caries/cracks/fractures on the root surface and/or root canal curvature more than 10 degrees. The specimens were decoronated to obtain 14 mm root lengths. The working length of the canals was determined by inserting a size 10 K-file (Dentsply Maillefer) up to the root canal terminus and subtracting 1 mm from this measurement. The size of the minor foramen was controlled using a size 25 K-file to the working length.
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International Endodontic Journal
When the K-file reached to the working length, the tooth was included into the study. According to these criteria, 48 specimens were selected for the study and assigned to the four root canal shaping groups described below (n = 12): Group 1: 150° CCW–30° CW: The angle of reciprocation was set at CCW = 150° and CW = 30° (angle of progression for each reciprocation was 120°). The instruments were used at a speed of 300 rpm. Group 2: 270° CCW–30° CW: The angle of reciprocation was set at CCW = 270° and CW = 30° (angle of progression for each reciprocation was 240°). The instruments were used at a speed of 300 rpm. Group 3: 360° CCW–30° CW: The angle of reciprocation was set at CCW = 360° and CW = 30° (angle of progression for each reciprocation was 330°). The instruments were used at a speed of 300 rpm. Group 4: Continuous rotation: The root canals were prepared at a rotational speed of 300 rpm and 200 g cm 1 torque. Before the root canal shaping procedures, a size 10 K-file was introduced into the root canal to establish patency through the canal terminus. For all groups, instrumentation was performed using an electric motor (Satelec Endo Dual, Acteon, France) that allows the user to modify and set the reciprocating angles in both CW and CCW directions. The root canals were filled with distilled water, and a Reciproc R25â instrument was introduced into the canal. After three pecking motions (not exceeding 3 mm), the debris on the instrument was cleaned with a sterile gauze and the root canal was irrigated using 2 mL of distilled water. When the instrument reached working length, the procedure was repeated using Reciproc R50â. Each instrument was used in one canal. The instrumentation of the root canal preparations was completed by one operator. To evaluate the apically extruded debris, the method of Myers & Montgomery (1991) was used. Empty Eppendorf tubes without stoppers were weighed with an electronic balance (Denver Instruments GmbH XPseries, G€ ottingen, Germany) which had an accuracy of 0.0001 g. Three consecutive weights were obtained for each tube, and the average measurement for each was considered to be its initial weight. The stoppers of the Eppendorf tubes were separated, and a hole created to accommodate the roots that were inserted up to the cementoenamel junction.
© 2015 International Endodontic Journal. Published by John Wiley & Sons Ltd
Arslan et al. Apically extruded debris, Reciproc, motion
A 27-gauge needle was placed alongside the stopper (to equalize the internal and external pressures). The gaps surrounding the hole, the Eppendorf tube and the needle were carefully filled with adhesive (Pattex Super Glue; T€ urk Henkel, Inc., Istanbul, Turkey) to prevent irrigant extrusion through the hole. After the completion of canal instrumentation, the stoppers of the vial and Eppendorf were removed. The surface of the root was washed with 1 mL of bidistilled water into the vial to collect the debris adhering to the root surface. The vials were then stored in an incubator at 37 °C for 10 days to evaporate the distilled water before weighing the dry debris. The net weight of the extruded debris was determined by subtracting the initial weight from the final weight. The data were analysed with one way analysis of variance and LSD post hoc tests. The tests were performed at the 95% confidence level (P = 0.05). All statistical analyses were performed using SPSS software (SPSS Inc., Chicago, IL, USA).
Results The amount of debris extrusion was 0.00013 0.00011 g for the 150° CCW–30° CW group, 0.00028 0.00036 g for the 270° CCW–30° CW, 0.00077 0.0011 g for the 360° CCW–30° CW and 0.0012 0.0007 g for the continuous rotation. The 150° CCW–30° CW and 270° CCW–30° CW reciprocating motions extruded significantly less debris than continuous rotation (P < 0.05). However, no significant differences were noted between the 360° CCW and 30° CW reciprocating motion and continuous rotation (P > 0.05). Likewise, there was no significant difference between the 150° CCW–30° CW and 270° CCW–30° CW reciprocating motions (P > 0.05) (Fig. 1).
Discussion There are conflicting results about the effect of reciprocating motion on debris extrusion. In fact, rotary instrumentation has been associated with less (B€ urklein & Sch€ afer 2012, B€ urklein et al. 2014), similar (Kocak et al. 2013) or more (De-Deus et al. 2015, Tinoco et al. 2014) debris extrusion compared to reciprocating instrumentation. However, in these studies single-file reciprocating instruments were compared with full-sequence instruments (B€ urklein & Sch€ afer 2012) or single-file rotary instruments, which have different cross-sectional designs (B€ urklein et al. 2014). However, the use of differently designed instruments, different number of files and root canal anatomy could cause these conflicting results, and it is not possible to segregate the influence of the reciprocal motion from the results of the aforementioned studies. Thus, the purpose of this laboratory study was to assess the amount of apically extruded debris using Reciprocâ instruments with different kinematics. In the present study, the same number and brands (Reciprocâ) of instruments with different kinematics were evaluated. According to the results, the null hypothesis was rejected, as significant differences in the weight of apically extruded debris were obtained between the groups. The results of the present study revealed that the 150° CCW–30° CW and 270° CCW–30° CW reciprocating motions extruded significantly less debris than continuous rotation. Because different alloys and instrumentation systems were evaluated in previous studies, direct comparison could not be performed between the results of the previous studies and the present study. Tinoco et al. (2014) evaluated the apical bacterial extrusion associated with two reciprocating single-file systems (WaveOne and Reciproc) compared with a conventional multifile rotary system and found
Figure 1 The quantity of apically extruded debris by experimental group.
© 2015 International Endodontic Journal. Published by John Wiley & Sons Ltd
International Endodontic Journal
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Apically extruded debris, Reciproc, motion Arslan et al.
that both reciprocating single-file systems extruded fewer bacteria apically than a conventional multifile rotary system. Similarly, De-Deus et al. (2015) found that a conventional multifile rotary system extruded significantly more debris than reciprocating single-file systems, which are broadly similar to the present results. However, Kocak et al. (2013) reported no significant differences between single-file reciprocating instruments and multifile rotary systems with respect to debris extrusion. Also, some rotary instrumentation was found to be associated with less debris extrusion compared to reciprocating instrumentation (B€ urklein & Sch€ afer 2012, B€ urklein et al. 2014). The differences between the studies might be due to the use of instruments with different alloys and designs. The Reciproc instruments have an S-shaped crosssectional design with sharp cutting edges. B€ urklein & Sch€ afer (2012) reported that an increased cutting ability may enhance debris transportation towards the apex when used in combination with reciprocating motion. According to B€ urklein & Sch€ afer (2012), continuous rotation may improve coronal transportation of dentine chips and debris by acting like a screw conveyor. However, several parameters amongst the groups, that is manufacturing methods, different designs, number of files and kinematics might affect the results. Moreover, Mtwo instruments (VDW) have the same S-shaped cross-sectional design as Reciproc instruments. However, according to B€ urklein & Sch€ afer (2012), the Reciproc system produced significantly more debris compared with the Mtwo system. Further studies should be conducted to understand the effects of instrument design alone on apically extruded debris. New endodontic motors allow the clinicians to modify the reciprocating angles in both CW and CCW directions. According to the results of the present study, Reciproc instruments extruded less debris when used in reciprocating motion than in continuous rotation. Because each brand of preparation instrument has different properties, that is manufacturing methods, designs or number of files, further studies should be conducted to determine the effect of different kinematics on the apically extruded debris for each brand of instruments.
Conclusion All of the kinematics resulted in apically extruded debris. However, the 150° CCW–30° CW and 270° CCW–30° CW reciprocating motions were associated with less extrusion than the continuous rotation.
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International Endodontic Journal
Acknowledgements This research was supported in part by an Ataturk University Research Fund (Project No: 2014/32). The authors deny any conflict of interests related to this study.
References B€ urklein S, Sch€ afer E (2012) Apically extruded debris with reciprocating single-file and full-sequence rotary instrumentation systems. Journal of Endodontics 38, 850–2. B€ urklein S, Benten S, Sch€ afer E (2014) Quantitative evaluation of apically extruded debris with different single-file systems: Reciproc, F360 and OneShape versus Mtwo. International Endodontic Journal 47, 405–9. De-Deus G, Neves A, Silva EJ et al. (2015) Apically extruded dentin debris by reciprocating single-file and multi-file rotary system. Clinical Oral Investigations, 19, 357–61. Er K, Sumer Z, Akpinar KE (2005) Apical extrusion of intracanal bacteria following use of two engine-driven instrumentation techniques. International Endodontic Journal 38, 871–6. Fairbourn DR, McWalter GM, Montgomery S (1987) The effect of four preparation techniques on the amount of apically extruded debris. Journal of Endodontics 13, 102–8. Kocak S, Kocak MM, Saglam BC, Turker SA, Sagsen B, Er O (2013) Apical extrusion of debris using self-adjusting file, reciprocating single-file, and 2 rotary instrumentation systems. Journal of Endodontics 39, 1278–80. Kustarci A, Akpinar KE, Er K (2008) Apical extrusion of intracanal debris and irrigant following use of various instrumentation techniques. Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontics 105, 257– 62. Myers GL, Montgomery S (1991) A comparison of weights of debris extruded apically by conventional filing and Canal Master techniques. Journal of Endodontics 17, 275–9. Seltzer S, Naidorf IJ (1985) Flare-ups in endodontics: I. Etiological factors. Journal of Endodontics 11, 472–8. Tanalp J, Kaptan F, Sert S, Kayahan B, Bayirl G (2006) Quantitative evaluation of the amount of apically extruded debris using 3 different rotary instrumentation systems. Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontics 101, 250–7. Tinaz AC, Alacam T, Uzun O, Maden M, Kayaoglu G (2005) The effect of disruption of apical constriction on periapical extrusion. Journal of Endodontics 31, 533–5. Tinoco JM, De-Deus G, Tinoco EM, Saavedra F, Fidel RA, Sassone LM (2014) Apical extrusion of bacteria when using reciprocating single-file and rotary multifile instrumentation systems. International Endodontic Journal 47, 560–6.
© 2015 International Endodontic Journal. Published by John Wiley & Sons Ltd
Comparison of apically extruded debris after root canal instrumentation using Reciprocâ instruments with various kinematics
anay1, M. Alsancak1, I. D. C € ndu € z1 H. Arslan1, E. Dog ß apar2, E. Karatasß1 & H. A. Gu 1
Department of Endodontics, Faculty of Dentistry, Ataturk University, Erzurum; and 2Department of Endodontics, Faculty of _ Dentistry, Izmir Katip C Turkey ß elebi University, Izmir,
Abstract anay E, Alsancak M, C Arslan H, Dog ß apar ID, Karatasß € ndu € z HA. Comparison of apically extruded debris E, Gu after root canal instrumentation using Reciprocâ instruments with various kinematics. International Endodontic Journal.
Aim To assess the amount of apically extruded debris using Reciprocâ instruments with different kinematics (150° counter clockwise [CCW]–30° clockwise [CW], 270° CCW–30° CW, 360° CCW–30° CW and continuous rotation). Methodology Forty-eight maxillary central incisors were selected and assigned to four root canal shaping groups as follows (n = 12): 150° CCW–30° CW, 270° CCW–30° CW, 360° CCW–30° CW and continuous rotation. Reciproc R25 and R50â instruments were used in all groups. Apically extruded debris was collected and dried in preweighed Eppendorf tubes. The
Introduction During root canal preparation, irrigants, dentine chips, pulp tissue and microorganisms may be extruded into the periradicular tissues and cause postoperative pain and complications (Seltzer & Naidorf 1985). Studies examining the apical extrusion of debris have reported that all instrumentation techniques and instruments are associated with the extrusion of debris (Fairbourn et al. 1987, Er et al. 2005, Tinaz et al. 2005, Tanalp et al. 2006, Kustarci et al. 2008).
Correspondence: Hakan Arslan, Department of Endodontics, Faculty of Dentistry, Ataturk University, Erzurum 26240, Turkey (Tel.: +90.442.325 4040- 2352; Fax: +90.442.325 2535; e-mail: [email protected]).
© 2015 International Endodontic Journal. Published by John Wiley & Sons Ltd
weight of extruded debris was assessed with an electronic balance. The data were analysed with one way analysis of variance and LSD post hoc tests (P = 0.05). Results The 150° CCW–30° CW and 270° CCW– 30° CW reciprocating motions extruded significantly less debris than continuous rotation (P < 0.05). However, no significant differences were found between the 360° CCW and 30° CW reciprocating motion and the continuous rotation (P > 0.05). Conclusions All instrument movements were associated with apically extruded debris. However, the 150° CCW–30° CW and 270° CCW–30° CW reciprocating motions were associated with less extrusion than continuous rotation. Keywords: debris extrusion, kinematics, motion, movement, reciprocation, rotary. Received 9 December 2014; accepted 17 March 2015
There are conflicting reports on the effect of reciprocating and rotating instruments on the quantity of apically extruded debris (B€ urklein & Sch€ afer 2012, Kocak et al. 2013, B€ urklein et al. 2014, De-Deus et al. 2015, Tinoco et al. 2014). B€ urklein & Sch€ afer (2012) reported that full-sequence rotary instrumentation using Mtwo (VDW, Munich, Germany) and ProTaper (Dentsply Maillefer, Ballaigues, Switzerland) instruments was associated with less debris extrusion compared with the use of Reciproc (VDW) and WaveOne (Dentsply Maillefer) reciprocating single-file systems. Similarly, B€ urklein et al. (2014) found that rotary instrumentation using OneShape and multiple file Mtwo instruments was associated with less debris extrusion compared to reciprocating instrumentation (Reciproc). However, Kocak et al. (2013) found no
International Endodontic Journal
1
Apically extruded debris, Reciproc, motion Arslan et al.
significant differences amongst single-file ProTaper F2 instruments, Revo-S SU instruments and Reciproc 25 instruments in terms of apically extruded debris. In contrast, Tinoco et al. (2014) found that WaveOne and Reciproc reciprocating single-file systems extruded fewer bacteria apically than a conventional multifile rotary system (BioRace; FKG Dentaire, La-Chaux-de-Fonds, Switzerland). Similarly, De-Deus et al. (2015) revealed that a conventional multifile rotary system (ProTaper) extruded significantly more debris than WaveOne and Reciproc. In previous reports, the single-file reciprocating instruments were compared with full-sequence instruments (B€ urklein & Sch€ afer 2012, B€ urklein et al. 2014). The use of different instruments and numbers of files could cause conflicting results, and it is not possible to segregate the influence of the reciprocal motion from these findings. There are no data in the literature related solely to the effect of root canal instrumentation using Reciprocâ instruments with different kinematics on the quantity of apically extruded debris. Therefore, the purpose of this laboratory study was to assess the amount of apically extruded debris using Reciprocâ instruments with different movements (150° counter clockwise [CCW]- 30° clockwise [CW], 270° CCW–30° CW, 360° CCW–30° CW and continuous rotation). The null hypothesis was that there would be no difference in weight of apically extruded debris amongst the groups.
Materials and methods The protocol of this study was approved by the Research Ethics Committee of Ataturk University, Erzurum, Turkey. Maxillary central incisors with similar lengths were selected from a collection of teeth that had been extracted for reasons unrelated to this study. Specimens were stored in 4 °C distilled water until use. Soft tissue and calculus were removed mechanically from the root surfaces with a periodontal scaler. The exclusion criteria were a tooth having more than one root canal and apical foramen, root canal treatment, internal/external resorption, immature root apices, caries/cracks/fractures on the root surface and/or root canal curvature more than 10 degrees. The specimens were decoronated to obtain 14 mm root lengths. The working length of the canals was determined by inserting a size 10 K-file (Dentsply Maillefer) up to the root canal terminus and subtracting 1 mm from this measurement. The size of the minor foramen was controlled using a size 25 K-file to the working length.
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International Endodontic Journal
When the K-file reached to the working length, the tooth was included into the study. According to these criteria, 48 specimens were selected for the study and assigned to the four root canal shaping groups described below (n = 12): Group 1: 150° CCW–30° CW: The angle of reciprocation was set at CCW = 150° and CW = 30° (angle of progression for each reciprocation was 120°). The instruments were used at a speed of 300 rpm. Group 2: 270° CCW–30° CW: The angle of reciprocation was set at CCW = 270° and CW = 30° (angle of progression for each reciprocation was 240°). The instruments were used at a speed of 300 rpm. Group 3: 360° CCW–30° CW: The angle of reciprocation was set at CCW = 360° and CW = 30° (angle of progression for each reciprocation was 330°). The instruments were used at a speed of 300 rpm. Group 4: Continuous rotation: The root canals were prepared at a rotational speed of 300 rpm and 200 g cm 1 torque. Before the root canal shaping procedures, a size 10 K-file was introduced into the root canal to establish patency through the canal terminus. For all groups, instrumentation was performed using an electric motor (Satelec Endo Dual, Acteon, France) that allows the user to modify and set the reciprocating angles in both CW and CCW directions. The root canals were filled with distilled water, and a Reciproc R25â instrument was introduced into the canal. After three pecking motions (not exceeding 3 mm), the debris on the instrument was cleaned with a sterile gauze and the root canal was irrigated using 2 mL of distilled water. When the instrument reached working length, the procedure was repeated using Reciproc R50â. Each instrument was used in one canal. The instrumentation of the root canal preparations was completed by one operator. To evaluate the apically extruded debris, the method of Myers & Montgomery (1991) was used. Empty Eppendorf tubes without stoppers were weighed with an electronic balance (Denver Instruments GmbH XPseries, G€ ottingen, Germany) which had an accuracy of 0.0001 g. Three consecutive weights were obtained for each tube, and the average measurement for each was considered to be its initial weight. The stoppers of the Eppendorf tubes were separated, and a hole created to accommodate the roots that were inserted up to the cementoenamel junction.
© 2015 International Endodontic Journal. Published by John Wiley & Sons Ltd
Arslan et al. Apically extruded debris, Reciproc, motion
A 27-gauge needle was placed alongside the stopper (to equalize the internal and external pressures). The gaps surrounding the hole, the Eppendorf tube and the needle were carefully filled with adhesive (Pattex Super Glue; T€ urk Henkel, Inc., Istanbul, Turkey) to prevent irrigant extrusion through the hole. After the completion of canal instrumentation, the stoppers of the vial and Eppendorf were removed. The surface of the root was washed with 1 mL of bidistilled water into the vial to collect the debris adhering to the root surface. The vials were then stored in an incubator at 37 °C for 10 days to evaporate the distilled water before weighing the dry debris. The net weight of the extruded debris was determined by subtracting the initial weight from the final weight. The data were analysed with one way analysis of variance and LSD post hoc tests. The tests were performed at the 95% confidence level (P = 0.05). All statistical analyses were performed using SPSS software (SPSS Inc., Chicago, IL, USA).
Results The amount of debris extrusion was 0.00013 0.00011 g for the 150° CCW–30° CW group, 0.00028 0.00036 g for the 270° CCW–30° CW, 0.00077 0.0011 g for the 360° CCW–30° CW and 0.0012 0.0007 g for the continuous rotation. The 150° CCW–30° CW and 270° CCW–30° CW reciprocating motions extruded significantly less debris than continuous rotation (P < 0.05). However, no significant differences were noted between the 360° CCW and 30° CW reciprocating motion and continuous rotation (P > 0.05). Likewise, there was no significant difference between the 150° CCW–30° CW and 270° CCW–30° CW reciprocating motions (P > 0.05) (Fig. 1).
Discussion There are conflicting results about the effect of reciprocating motion on debris extrusion. In fact, rotary instrumentation has been associated with less (B€ urklein & Sch€ afer 2012, B€ urklein et al. 2014), similar (Kocak et al. 2013) or more (De-Deus et al. 2015, Tinoco et al. 2014) debris extrusion compared to reciprocating instrumentation. However, in these studies single-file reciprocating instruments were compared with full-sequence instruments (B€ urklein & Sch€ afer 2012) or single-file rotary instruments, which have different cross-sectional designs (B€ urklein et al. 2014). However, the use of differently designed instruments, different number of files and root canal anatomy could cause these conflicting results, and it is not possible to segregate the influence of the reciprocal motion from the results of the aforementioned studies. Thus, the purpose of this laboratory study was to assess the amount of apically extruded debris using Reciprocâ instruments with different kinematics. In the present study, the same number and brands (Reciprocâ) of instruments with different kinematics were evaluated. According to the results, the null hypothesis was rejected, as significant differences in the weight of apically extruded debris were obtained between the groups. The results of the present study revealed that the 150° CCW–30° CW and 270° CCW–30° CW reciprocating motions extruded significantly less debris than continuous rotation. Because different alloys and instrumentation systems were evaluated in previous studies, direct comparison could not be performed between the results of the previous studies and the present study. Tinoco et al. (2014) evaluated the apical bacterial extrusion associated with two reciprocating single-file systems (WaveOne and Reciproc) compared with a conventional multifile rotary system and found
Figure 1 The quantity of apically extruded debris by experimental group.
© 2015 International Endodontic Journal. Published by John Wiley & Sons Ltd
International Endodontic Journal
3
Apically extruded debris, Reciproc, motion Arslan et al.
that both reciprocating single-file systems extruded fewer bacteria apically than a conventional multifile rotary system. Similarly, De-Deus et al. (2015) found that a conventional multifile rotary system extruded significantly more debris than reciprocating single-file systems, which are broadly similar to the present results. However, Kocak et al. (2013) reported no significant differences between single-file reciprocating instruments and multifile rotary systems with respect to debris extrusion. Also, some rotary instrumentation was found to be associated with less debris extrusion compared to reciprocating instrumentation (B€ urklein & Sch€ afer 2012, B€ urklein et al. 2014). The differences between the studies might be due to the use of instruments with different alloys and designs. The Reciproc instruments have an S-shaped crosssectional design with sharp cutting edges. B€ urklein & Sch€ afer (2012) reported that an increased cutting ability may enhance debris transportation towards the apex when used in combination with reciprocating motion. According to B€ urklein & Sch€ afer (2012), continuous rotation may improve coronal transportation of dentine chips and debris by acting like a screw conveyor. However, several parameters amongst the groups, that is manufacturing methods, different designs, number of files and kinematics might affect the results. Moreover, Mtwo instruments (VDW) have the same S-shaped cross-sectional design as Reciproc instruments. However, according to B€ urklein & Sch€ afer (2012), the Reciproc system produced significantly more debris compared with the Mtwo system. Further studies should be conducted to understand the effects of instrument design alone on apically extruded debris. New endodontic motors allow the clinicians to modify the reciprocating angles in both CW and CCW directions. According to the results of the present study, Reciproc instruments extruded less debris when used in reciprocating motion than in continuous rotation. Because each brand of preparation instrument has different properties, that is manufacturing methods, designs or number of files, further studies should be conducted to determine the effect of different kinematics on the apically extruded debris for each brand of instruments.
Conclusion All of the kinematics resulted in apically extruded debris. However, the 150° CCW–30° CW and 270° CCW–30° CW reciprocating motions were associated with less extrusion than the continuous rotation.
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International Endodontic Journal
Acknowledgements This research was supported in part by an Ataturk University Research Fund (Project No: 2014/32). The authors deny any conflict of interests related to this study.
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