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The Effect of Disruption of Apical Constriction on Periapical Extrusion
Basic Research–Technology
The Effect of Disruption of Apical Constriction on Periapical Extrusion Ali Cemal Tinaz, DDS, PhD, Tayfun Alacam, DDS, PhD, Ozgur Uzun, DDS, PhD, Murat Maden, DDS, PhD, and Guven Kayaoglu, DDS Abstract The aim of this study was to compare the amount of apical extrusion during manual instrumentation and engine-driven rotary instrumentation in teeth with disrupted apical constriction. Fifty-two teeth were divided into two groups comprising 26 teeth each. Teeth in each group were further divided into two sub-groups, the apices of which were enlarged approximately to a diameter of 0.2 mm and 0.4 mm. One group was instrumented using standardized technique with K-files and the other with ProFile .04 Taper Series 29, while irrigating with sodium hypochlorite. Glass vial model was modified for collection of extruded debris and irrigant as well as to integrate an electronic apex locator to the experimental assemble. The statistical analysis using Student’s t test revealed no significant difference between instrumentation with K-files and ProFile .04 taper files (p ⬎ 0.05). There was a tendency with both techniques to extrude apically more material as the diameter of the apical patency increased.
Key Words Apical extrusion, engin-driven rotary instruments, apical disruption
Dr Cemal Tinaz is Associate Professor, Department of Conservative Dentistry and Endodontics, Dental Faculty, Gazi University, Ankara, Turkey. Dr Alacam is Professor and Head of Department of Conservative Dentistry and Endodontics, Dental Faculty, Gazi University, Ankara, Turkey. Drs. Uzun and Kayaoglu are Researchers for the Department of Conservative Dentistry and Endodontics, Dental Faculty, Gazi University, Ankara, Turkey. Dr. Maden is Associate Professor, Department of Conservative Dentistry and Endodontics, Dental Faculty, Suleyman Demirel University, Isparta, Turkey. Address requests for reprints to Dr. Cemal Tinaz, Department of Conservative Dentistry and Endodontics, Dental Faculty, Gazi University, 82 Street Emek, 06510, Ankara, Turkey; E-mail: [email protected]. Copyright ©2005 by the American Association of Endodontists
JOE — Volume 31, Number 7, July 2005
T
horough debridement of root canals using files and irrigation solutions is essential for the success of endodontic treatment. However, dentinal chips, pulpal fragments, necrotic debris, irrigants, and micro-organisms are inevitably pushed out from the root canal into periapical tissues during chemo-mechanical preparation. Extrusion of these elements may cause undesired consequences such as induction of inflammation and postoperative pain, and delay of periapical healing (1). A large number of studies have dealt with the effect of various root canal preparation techniques and instruments on the amount of the apically extruded dentinal debris and irrigant (2–11). The tested instruments were generally conventional hand files and engine-driven rotary nickel-titanium files. While apical extrusion of dentinal debris and irrigants have been observed with the use of all presently known root canal preparation techniques and instruments, less dentinal debris extrusion was associated with the use of engine-driven rotary instruments (7, 10). On the other hand, others report no significant difference between hand instrumentation and engine-driven rotary instrumentation (8). It has also been observed that less dentinal debris and irrigant were extruded when the instrumentation was performed 1 mm short of the apical foramen (2, 5, 7). In these studies, the working length was adjusted visually or radiographically; and to our knowledge, apex locator was not used in any previous apical extrusion study. In clinical practice, there may be instances where proper apical constriction lacks; it may not have formed in immature teeth or it may be resorbed as a result of a long-standing periapical lesion. Besides, the apical constriction may be disrupted iatrogenically (e.g. because of improper working length determination) or intentionally by the operator (e.g. to facilitate the discharge of periapical abscess through the root canal). One study has indicated that apical transportation may occur even after use of a #10 file as the apical patency file, a quite small size file (12). Apical transportation can be associated with disruption of apical constriction because of forces around the outer curve of the file. It seems, therefore, likely that apical disruption may occur even during routine endodontic treatment. The lack of an apical constriction in such teeth may be speculated to yield increased apical extrusion during endodontic treatment. The aim of this study was to compare the amount of apical extrusion during manual instrumentation (K-files) and engine-driven rotary instrumentation (ProFile .04 Taper Series 29) in teeth with disrupted apical constriction.
Materials and Methods Specimen Selection Extracted human maxillary central and lateral incisors with mature apices were used. Teeth were left in 2.6% sodium hypochlorite (NaOCl) for 2 h to clean the periodontal tissue remnants on root surfaces. Root surfaces were further scaled with a periodontal curette and the teeth were stored in 10% buffered formalin phosphate solution. The teeth were decoronated to obtain specimens of identical length. Facial and lateral radiographs were taken (RVG, Trophy, France) to ensure that the teeth had single canals. The degree of the root curvature was determined using the method described by Schneider (13). Teeth with more than 10 degrees root curvature and with too large or too narrow canals were excluded from the study. Under these circumstances, 52 teeth were selected for the study.
Disrupted Apical Constriction
533
Basic Research–Technology Experimental Design The teeth were divided into two groups comprising 26 teeth each. One group was manually instrumented and the other with engine-driven rotary instruments. Teeth in each group were further divided into two sub-groups. In sub-group 1 and sub-group 2, a #15 K-file and a #30 K-file, respectively, was placed into the root canal and advanced until the tip of the file passed 2 mm out from the apical foramen. In this way, apical patencies of approximately 0.2 mm and 0.4 mm were achieved, respectively. A previously described method was modified for debris collection (5). Glass vials were entirely filled with 0.9% saline solution. The teeth were forced through a precut hole in rubber stoppers that conformed to the mouth of the glass vials. A bent 25-gauge needle was also forced alongside the rubber stopper to serve as a drainage cannula. The rubber stopper-root-needle assembly was then fitted into the mouth of the saline-filled vial. Excess of the saline solution drained out through the cannula at this time, and was discarded. Working length determination in all teeth was done using TRI Auto ZX (J. Morita Co., Kyoto, Japan) in the electronic apex locator mode switched on. Lip clip was attached to the drainage cannula. K-files attached to the file holder cord were placed into the root canals and advanced apically in the root canal until 0.5 LED was read on the console of the TRI Auto ZX. This ensured a working length 0.5-mm short of the apical foramen. Manual instrumentation was performed according to a standardized technique described previously (14). Briefly, the largest K-file reaching the working length was used first with a quarter clockwise rotation followed by a pull-back motion and used repeatedly until it became loose at the working length. Engine-driven rotary instrumentation employed ProFile .04 Series 29 nickel-titanium files mounted on TRI Auto ZX switched to manual mode. Orifice shaper and .06 series were not used. All teeth were prepared three sizes larger than the first file to bind. Irrigation solution was delivered by means of a 5-ml disposable plastic syringe with an attached 23-gauge stainless steel needle. Irrigation was with 0.5 ml of 2.6% NaOCl when advancing to a larger size file. The tip of the needle was never allowed to bind to the root canal walls. A final rinse was performed again with 0.5 ml of NaOCl. Thus, a total volume of 2.5 ml of NaOCl was used in each case. All operatory procedures were performed by one person. Extruded irrigant was collected from the drainage cannula into a disposable plastic insulin syringe. The volume of the collected fluid was determined by means of a 0.1-ml incremented measure supplied on the syringe. The amount of the extruded debris collected in the vial was determined by means of an analytic balance at 10(⫺5) gram precision, after evaporating the fluid in the vial and subtracting the weight of the vial and salt deposits. The data obtained were analyzed using Student’s t test, using ␣ ⫽ 0.05 as the level for statistical significance.
Results The results are summarized in Figs. 1 and 2. No statistically significant difference as to the amount of extruded debris and irrigant was found between manual instrumentation with K-files and rotary instrumentation with ProFile .04 taper files (p ⬎ 0.05). There was also no significant difference between 0.2 mm and 0.4 mm apical patency specimens, except for the amount of extruded debris with manual instrumentation that was significantly more in 0.4 mm apical patency specimens (p ⬍ 0.05). 534
Cemal Tinaz et al.
Figure 1. The amount of extruded dentinal debris with manual instrumentation and with rotary instrumentation.
Figure 2. The amount of extruded irrigant with manual instrumentation and with rotary instrumentation.
Discussion The main findings in this study were that no significant difference as to the amount of apically extruded material was observed between manual instrumentation using conventional files and engine-driven instrumentation using ProFile .04 taper files and that there was a tendency to extrude more material as the extent of the apical patency increased. Although there have been several studies where the apically extruded material was collected in an isolated chamber, as described elsewhere (5), this is the first study to integrate an apex locator to the conventional experimental design. The vials were filled with saline solution as an electrolyte to ensure the functioning of the apex locator. This method was proven to work in a previous apex location study (15). The 25-gauge needle that functioned as an air vent in previous debris extrusion studies functioned as a drain to reflect the amount of the extruded irrigant in this study. In debris extrusion studies, it is a common observation that large deviations from mean values are encountered. In some studies these values were discarded as outliers (3, 4); but we, like others (5, 8), included these values for the statistical analysis. This is the reason that large standard deviations were observed in this study. The finding in our study that no significant difference exists between manual instrumentation and engine-driven rotary instrumentation, with respect to apical extrusion, supports the findings of a previous study (8), but contrasts the findings of other studies where step-back filing with K-files extruded significantly more debris than instrumentation with ProFile .04 system (7, 9). The reason for the different results may be because the latter studies employed a push-pull motion (linear motion) when using K-files. On the contrary, we, and others (8), used
JOE — Volume 31, Number 7, July 2005
Basic Research–Technology K-files with rotational forces. The general view in endodontic literature is that linear filing motion extrudes more debris apically than rotational motion. One study evaluating the role of apical constriction on periapical extrusion has indicated that the apically extruded material was ‘paradoxically’ less when the constriction was enlarged than when the constriction remained intact (11). Contrary to this finding, our study, expectedly, has indicated an increase in the amount of the apically extruded material parallel to increase in the diameter of the apical patency. This difference is probably because of variations in study designs. In the former study, first, they instrumented the root canal to a certain size without disrupting the apical constriction and measured apical extrusion, then disrupted the apical constriction and continued instrumentation to larger sizes and measured apical extrusion again. The fact that there was more space coronally for the escape of debris and irrigant, because the teeth were already enlarged to some extent, may explain why there was less apical extrusion in teeth with disrupted apical constriction. In this study, compared with previous studies, very small amounts of debris and irrigant extrusion were observed. This may be a result of the total amount of irrigant used in the study that was some folds less than those used in previous studies (5–11). According to Vande Visse and Brilliant (16) debris extrusion is closely associated with use of an irrigant. Previous studies are controversial in terms of correlation between the amount of apically extruded debris and irrigant. Although some report a positive correlation (8, 10), others report no correlation (5). In our study, no consistent correlation was found between the amount of the apically extruded debris and the irrigant. Postoperative pain is a common finding in endodontic treatment (17, 18) and is quite likely to develop as a result of extrusion of materials from root canal to periapical tissues during treatment. Sodium hypochlorite as one of the most commonly used endodontic irrigant has a very good dentin disinfecting activity (19) and tissue dissolving capacity (20). A recent study has shown its effectiveness in preventing inoculation of periapical tissues with bacteria contaminated patency files (21). Therefore, it remains as an indispensable irrigation solution in endodontic treatment. However, there are also concerns about its cytotoxicity (22); and the endodontic literature contains several complications because of inadvertent forcing of sodium hypochlorite to periradicular tissues which present with severe pain, swelling, ecchymosis, bleeding from the root canal, and even long-term paresthesia (23–25). To avoid these, irrigation is recommended to be carried out cautiously; with low pressure and ensuring that the excess irrigant leaves the root canal via the access cavity. Consequences of the contact of dentin chips with periapical tissues were examined in animal studies. While microbe-free dentin chips applied as apical plugs were well tolerated by periapical tissues of monkey (26), results with infected dentin chips applied similarly were unfavorable (27). However, in practice it is hardly possible to know that the rasped dentin is sterile and will not provoke inflammatory response at the periapical site. Also, some bacterial species resistant to killing by the elements of the host defense has the potential to sustain inflammatory response and to delay healing when translocated from the root canal into the periapical lesion (28). Aside from local effects, extrusion of microbes to extra-radicular tissues during endodontic treatment has the potential to bring about serious systemic diseases such as endocarditis, brain abscesses and septicemia, particularly in compromised patients (29). Therefore, every effort should be exerted to limit the periapical extrusion of materials during treatment. The results of this study suggest that manual instrumentation with K-files and engine-driven rotary instrumentation with ProFile .04 taper system perform similar with respect to apical extrusion in teeth with
JOE — Volume 31, Number 7, July 2005
varying extent of apical patency. It is also indicated that a tendency for increased apical extrusion exists with both techniques as the diameter of the apical patency increases.
References 1. Seltzer S, Naidorf IJ. Flare-ups in endodontics: I. Etiological factors. J Endod 1985; 11:472– 8. 2. Martin H, Cunningham WT. The effect of endosonic and hand manipulation on the amount of root canal material extruded. Oral Surg Oral Med Oral Pathol 1982;53: 611–3. 3. Fairbourn DR, McWalter GM, Montgomery S. The effect of four preparation techniques on the amount of apically extruded debris. J Endod 1987;13:102– 8. 4. McKendry DJ. Comparison of balanced forces, endosonic, and step-back filing instrumentation techniques: quantification of extruded apical debris. J Endod 1990; 16:24 –7. 5. Myers GL, Montgomery S. A comparison of weights of debris extruded apically by conventional filing and Canal Master techniques. J Endod 1991;17:275–9. 6. Al-Omari MA, Dummer PM. Canal blockage and debris extrusion with eight preparation techniques. J Endod 1995;21:154 – 8. 7. Beeson TJ, Hartwell GR, Thornton JD, Gunsolley JC. Comparison of debris extruded apically in straight canals: conventional filing versus profile. 04 Taper series 29. J Endod 1998;24:18 –22. 8. Hinrichs RE, Walker WA, Schindler WG. A comparison of apically extruded debris using handpiece-driven nickel-titanium instrument systems. J Endod 1998;24:102– 6. 9. Reddy SA, Hicks ML. Apical extrusion of debris using two hand and two rotary instrumentation techniques. 1998;24:180 –3. 10. Ferraz CC, Gomes NV, Gomes BP, Zaia AA, Teixeira FB, Souza-Filho FJ. Apical extrusion of debris and irrigants using two hand and three engine-driven instrumentation techniques. Int Endod J 2001;34:354 – 8. 11. Lambrianidis T, Tosounidou E, Tzoanapoulou M. The effect of maintaining apical patency on periapical extrusion. J Endod 2001;27:696 – 8. 12. Goldberg F, Massone EJ. Patency file and apical transportation: an in vitro study. J Endod 2002;28:510 –1. 13. Schneider SW. A comparison of canal preparations in straight and curved canals. Oral Surg 1971;32:271–5. 14. Cohen S, Richard CB. Pathways of the pulp, 6th ed. St. Louis, MO: Mosby, 1994:193. 15. Weiger R, John C, Geigle H, Lo¨st C. An in vitro comparison of two modern apex locators. J Endod 1999;25:765– 8. 16. VandeVisse JE, Brilliant JD. Effect of irrigation on the production of extruded material at the root apex during instrumentation. J Endod 1975;1:243– 6. 17. Negm MM. Intracanal use of a corticosteroid-antibiotic compound for the management of posttreatment endodontic pain. Oral Surg Oral Med Oral Pathol 2001;92:435–9. 18. Nusstein JM, Reader A, Beck M. Effect of drainage upon access on postoperative endodontic pain and swelling in symptomatic necrotic teeth. J Endod 2002;28:584 – 8. 19. Ørstavik D, Haapasalo M. Disinfection by endodontic irrigants and dressings of experimentally infected dentinal tubules. Endod Dent Traumatol 1990;6:142–9. 20. Zehnder M, Kosicki D, Luder H, Sener B, Waltimo T. Tissue-dissolving capacity and antibacterial effect of buffered and unbuffered hypochlorite solutions. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2002;94:756 – 62. 21. Izu KH, Thomas SJ, Zhang P, Izu AE, Michalek S. Effectiveness of sodium hypochlorite in preventing inoculation of periapical tissues with contaminated patency files. J Endod 2004;30:92– 4. 22. Pashley EL, Birdsong NL, Bowman K, Pashley DH. Cytotoxic effects of NaOCl on vital tissue. J Endod 1985;11:525– 8. 23. Reeh ES, Messer HH. Long-term paresthesia following inadvertent forcing of sodium hypochlorite through perforation in maxillary incisor. Endod Dent Traumatol 1989; 5:200 –3. 24. Hu¨lsmann M, Hahn W. Complications during root canal irrigation-literature review and case reports. Int Endod J 2000;33:186 –93. 25. Hales JJ, Jackson CR, Everett AP, Moore SH. Treatment protocol for the management of a sodium hypochlorite accident during endodontic therapy. Gen Dent 2001;49: 278 – 81. 26. Tronstad L. Tissue reactions following apical plugging of the root canal with dentin chips in monkey teeth subjected to pulpectomy. Oral Surg Oral Med Oral Pathol 1978;45:297–304. 27. Holland R, Souza V, Nery MJ, Mello W, Bernabe PF, Otoboni FJA. Tissue reactions following apical plugging of the root canal with infected dentin chips. A histologic study in dogs’ teeth. Oral Surg Oral Med Oral Pathol 1980;49:366 –9. 28. Kayaoglu G, Ørstavik D. Virulence factors of Enterococcus faecalis: relationship to endodontic disease. Crit Rev Oral Biol Med 2004;15:308 –20. 29. Debelian GJ, Olsen I, Tronstad L. Bacteremia in conjunction with endodontic therapy. Endod Dent Traumatol 1994;11:142–9.
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The Effect of Disruption of Apical Constriction on Periapical Extrusion Ali Cemal Tinaz, DDS, PhD, Tayfun Alacam, DDS, PhD, Ozgur Uzun, DDS, PhD, Murat Maden, DDS, PhD, and Guven Kayaoglu, DDS Abstract The aim of this study was to compare the amount of apical extrusion during manual instrumentation and engine-driven rotary instrumentation in teeth with disrupted apical constriction. Fifty-two teeth were divided into two groups comprising 26 teeth each. Teeth in each group were further divided into two sub-groups, the apices of which were enlarged approximately to a diameter of 0.2 mm and 0.4 mm. One group was instrumented using standardized technique with K-files and the other with ProFile .04 Taper Series 29, while irrigating with sodium hypochlorite. Glass vial model was modified for collection of extruded debris and irrigant as well as to integrate an electronic apex locator to the experimental assemble. The statistical analysis using Student’s t test revealed no significant difference between instrumentation with K-files and ProFile .04 taper files (p ⬎ 0.05). There was a tendency with both techniques to extrude apically more material as the diameter of the apical patency increased.
Key Words Apical extrusion, engin-driven rotary instruments, apical disruption
Dr Cemal Tinaz is Associate Professor, Department of Conservative Dentistry and Endodontics, Dental Faculty, Gazi University, Ankara, Turkey. Dr Alacam is Professor and Head of Department of Conservative Dentistry and Endodontics, Dental Faculty, Gazi University, Ankara, Turkey. Drs. Uzun and Kayaoglu are Researchers for the Department of Conservative Dentistry and Endodontics, Dental Faculty, Gazi University, Ankara, Turkey. Dr. Maden is Associate Professor, Department of Conservative Dentistry and Endodontics, Dental Faculty, Suleyman Demirel University, Isparta, Turkey. Address requests for reprints to Dr. Cemal Tinaz, Department of Conservative Dentistry and Endodontics, Dental Faculty, Gazi University, 82 Street Emek, 06510, Ankara, Turkey; E-mail: [email protected]. Copyright ©2005 by the American Association of Endodontists
JOE — Volume 31, Number 7, July 2005
T
horough debridement of root canals using files and irrigation solutions is essential for the success of endodontic treatment. However, dentinal chips, pulpal fragments, necrotic debris, irrigants, and micro-organisms are inevitably pushed out from the root canal into periapical tissues during chemo-mechanical preparation. Extrusion of these elements may cause undesired consequences such as induction of inflammation and postoperative pain, and delay of periapical healing (1). A large number of studies have dealt with the effect of various root canal preparation techniques and instruments on the amount of the apically extruded dentinal debris and irrigant (2–11). The tested instruments were generally conventional hand files and engine-driven rotary nickel-titanium files. While apical extrusion of dentinal debris and irrigants have been observed with the use of all presently known root canal preparation techniques and instruments, less dentinal debris extrusion was associated with the use of engine-driven rotary instruments (7, 10). On the other hand, others report no significant difference between hand instrumentation and engine-driven rotary instrumentation (8). It has also been observed that less dentinal debris and irrigant were extruded when the instrumentation was performed 1 mm short of the apical foramen (2, 5, 7). In these studies, the working length was adjusted visually or radiographically; and to our knowledge, apex locator was not used in any previous apical extrusion study. In clinical practice, there may be instances where proper apical constriction lacks; it may not have formed in immature teeth or it may be resorbed as a result of a long-standing periapical lesion. Besides, the apical constriction may be disrupted iatrogenically (e.g. because of improper working length determination) or intentionally by the operator (e.g. to facilitate the discharge of periapical abscess through the root canal). One study has indicated that apical transportation may occur even after use of a #10 file as the apical patency file, a quite small size file (12). Apical transportation can be associated with disruption of apical constriction because of forces around the outer curve of the file. It seems, therefore, likely that apical disruption may occur even during routine endodontic treatment. The lack of an apical constriction in such teeth may be speculated to yield increased apical extrusion during endodontic treatment. The aim of this study was to compare the amount of apical extrusion during manual instrumentation (K-files) and engine-driven rotary instrumentation (ProFile .04 Taper Series 29) in teeth with disrupted apical constriction.
Materials and Methods Specimen Selection Extracted human maxillary central and lateral incisors with mature apices were used. Teeth were left in 2.6% sodium hypochlorite (NaOCl) for 2 h to clean the periodontal tissue remnants on root surfaces. Root surfaces were further scaled with a periodontal curette and the teeth were stored in 10% buffered formalin phosphate solution. The teeth were decoronated to obtain specimens of identical length. Facial and lateral radiographs were taken (RVG, Trophy, France) to ensure that the teeth had single canals. The degree of the root curvature was determined using the method described by Schneider (13). Teeth with more than 10 degrees root curvature and with too large or too narrow canals were excluded from the study. Under these circumstances, 52 teeth were selected for the study.
Disrupted Apical Constriction
533
Basic Research–Technology Experimental Design The teeth were divided into two groups comprising 26 teeth each. One group was manually instrumented and the other with engine-driven rotary instruments. Teeth in each group were further divided into two sub-groups. In sub-group 1 and sub-group 2, a #15 K-file and a #30 K-file, respectively, was placed into the root canal and advanced until the tip of the file passed 2 mm out from the apical foramen. In this way, apical patencies of approximately 0.2 mm and 0.4 mm were achieved, respectively. A previously described method was modified for debris collection (5). Glass vials were entirely filled with 0.9% saline solution. The teeth were forced through a precut hole in rubber stoppers that conformed to the mouth of the glass vials. A bent 25-gauge needle was also forced alongside the rubber stopper to serve as a drainage cannula. The rubber stopper-root-needle assembly was then fitted into the mouth of the saline-filled vial. Excess of the saline solution drained out through the cannula at this time, and was discarded. Working length determination in all teeth was done using TRI Auto ZX (J. Morita Co., Kyoto, Japan) in the electronic apex locator mode switched on. Lip clip was attached to the drainage cannula. K-files attached to the file holder cord were placed into the root canals and advanced apically in the root canal until 0.5 LED was read on the console of the TRI Auto ZX. This ensured a working length 0.5-mm short of the apical foramen. Manual instrumentation was performed according to a standardized technique described previously (14). Briefly, the largest K-file reaching the working length was used first with a quarter clockwise rotation followed by a pull-back motion and used repeatedly until it became loose at the working length. Engine-driven rotary instrumentation employed ProFile .04 Series 29 nickel-titanium files mounted on TRI Auto ZX switched to manual mode. Orifice shaper and .06 series were not used. All teeth were prepared three sizes larger than the first file to bind. Irrigation solution was delivered by means of a 5-ml disposable plastic syringe with an attached 23-gauge stainless steel needle. Irrigation was with 0.5 ml of 2.6% NaOCl when advancing to a larger size file. The tip of the needle was never allowed to bind to the root canal walls. A final rinse was performed again with 0.5 ml of NaOCl. Thus, a total volume of 2.5 ml of NaOCl was used in each case. All operatory procedures were performed by one person. Extruded irrigant was collected from the drainage cannula into a disposable plastic insulin syringe. The volume of the collected fluid was determined by means of a 0.1-ml incremented measure supplied on the syringe. The amount of the extruded debris collected in the vial was determined by means of an analytic balance at 10(⫺5) gram precision, after evaporating the fluid in the vial and subtracting the weight of the vial and salt deposits. The data obtained were analyzed using Student’s t test, using ␣ ⫽ 0.05 as the level for statistical significance.
Results The results are summarized in Figs. 1 and 2. No statistically significant difference as to the amount of extruded debris and irrigant was found between manual instrumentation with K-files and rotary instrumentation with ProFile .04 taper files (p ⬎ 0.05). There was also no significant difference between 0.2 mm and 0.4 mm apical patency specimens, except for the amount of extruded debris with manual instrumentation that was significantly more in 0.4 mm apical patency specimens (p ⬍ 0.05). 534
Cemal Tinaz et al.
Figure 1. The amount of extruded dentinal debris with manual instrumentation and with rotary instrumentation.
Figure 2. The amount of extruded irrigant with manual instrumentation and with rotary instrumentation.
Discussion The main findings in this study were that no significant difference as to the amount of apically extruded material was observed between manual instrumentation using conventional files and engine-driven instrumentation using ProFile .04 taper files and that there was a tendency to extrude more material as the extent of the apical patency increased. Although there have been several studies where the apically extruded material was collected in an isolated chamber, as described elsewhere (5), this is the first study to integrate an apex locator to the conventional experimental design. The vials were filled with saline solution as an electrolyte to ensure the functioning of the apex locator. This method was proven to work in a previous apex location study (15). The 25-gauge needle that functioned as an air vent in previous debris extrusion studies functioned as a drain to reflect the amount of the extruded irrigant in this study. In debris extrusion studies, it is a common observation that large deviations from mean values are encountered. In some studies these values were discarded as outliers (3, 4); but we, like others (5, 8), included these values for the statistical analysis. This is the reason that large standard deviations were observed in this study. The finding in our study that no significant difference exists between manual instrumentation and engine-driven rotary instrumentation, with respect to apical extrusion, supports the findings of a previous study (8), but contrasts the findings of other studies where step-back filing with K-files extruded significantly more debris than instrumentation with ProFile .04 system (7, 9). The reason for the different results may be because the latter studies employed a push-pull motion (linear motion) when using K-files. On the contrary, we, and others (8), used
JOE — Volume 31, Number 7, July 2005
Basic Research–Technology K-files with rotational forces. The general view in endodontic literature is that linear filing motion extrudes more debris apically than rotational motion. One study evaluating the role of apical constriction on periapical extrusion has indicated that the apically extruded material was ‘paradoxically’ less when the constriction was enlarged than when the constriction remained intact (11). Contrary to this finding, our study, expectedly, has indicated an increase in the amount of the apically extruded material parallel to increase in the diameter of the apical patency. This difference is probably because of variations in study designs. In the former study, first, they instrumented the root canal to a certain size without disrupting the apical constriction and measured apical extrusion, then disrupted the apical constriction and continued instrumentation to larger sizes and measured apical extrusion again. The fact that there was more space coronally for the escape of debris and irrigant, because the teeth were already enlarged to some extent, may explain why there was less apical extrusion in teeth with disrupted apical constriction. In this study, compared with previous studies, very small amounts of debris and irrigant extrusion were observed. This may be a result of the total amount of irrigant used in the study that was some folds less than those used in previous studies (5–11). According to Vande Visse and Brilliant (16) debris extrusion is closely associated with use of an irrigant. Previous studies are controversial in terms of correlation between the amount of apically extruded debris and irrigant. Although some report a positive correlation (8, 10), others report no correlation (5). In our study, no consistent correlation was found between the amount of the apically extruded debris and the irrigant. Postoperative pain is a common finding in endodontic treatment (17, 18) and is quite likely to develop as a result of extrusion of materials from root canal to periapical tissues during treatment. Sodium hypochlorite as one of the most commonly used endodontic irrigant has a very good dentin disinfecting activity (19) and tissue dissolving capacity (20). A recent study has shown its effectiveness in preventing inoculation of periapical tissues with bacteria contaminated patency files (21). Therefore, it remains as an indispensable irrigation solution in endodontic treatment. However, there are also concerns about its cytotoxicity (22); and the endodontic literature contains several complications because of inadvertent forcing of sodium hypochlorite to periradicular tissues which present with severe pain, swelling, ecchymosis, bleeding from the root canal, and even long-term paresthesia (23–25). To avoid these, irrigation is recommended to be carried out cautiously; with low pressure and ensuring that the excess irrigant leaves the root canal via the access cavity. Consequences of the contact of dentin chips with periapical tissues were examined in animal studies. While microbe-free dentin chips applied as apical plugs were well tolerated by periapical tissues of monkey (26), results with infected dentin chips applied similarly were unfavorable (27). However, in practice it is hardly possible to know that the rasped dentin is sterile and will not provoke inflammatory response at the periapical site. Also, some bacterial species resistant to killing by the elements of the host defense has the potential to sustain inflammatory response and to delay healing when translocated from the root canal into the periapical lesion (28). Aside from local effects, extrusion of microbes to extra-radicular tissues during endodontic treatment has the potential to bring about serious systemic diseases such as endocarditis, brain abscesses and septicemia, particularly in compromised patients (29). Therefore, every effort should be exerted to limit the periapical extrusion of materials during treatment. The results of this study suggest that manual instrumentation with K-files and engine-driven rotary instrumentation with ProFile .04 taper system perform similar with respect to apical extrusion in teeth with
JOE — Volume 31, Number 7, July 2005
varying extent of apical patency. It is also indicated that a tendency for increased apical extrusion exists with both techniques as the diameter of the apical patency increases.
References 1. Seltzer S, Naidorf IJ. Flare-ups in endodontics: I. Etiological factors. J Endod 1985; 11:472– 8. 2. Martin H, Cunningham WT. The effect of endosonic and hand manipulation on the amount of root canal material extruded. Oral Surg Oral Med Oral Pathol 1982;53: 611–3. 3. Fairbourn DR, McWalter GM, Montgomery S. The effect of four preparation techniques on the amount of apically extruded debris. J Endod 1987;13:102– 8. 4. McKendry DJ. Comparison of balanced forces, endosonic, and step-back filing instrumentation techniques: quantification of extruded apical debris. J Endod 1990; 16:24 –7. 5. Myers GL, Montgomery S. A comparison of weights of debris extruded apically by conventional filing and Canal Master techniques. J Endod 1991;17:275–9. 6. Al-Omari MA, Dummer PM. Canal blockage and debris extrusion with eight preparation techniques. J Endod 1995;21:154 – 8. 7. Beeson TJ, Hartwell GR, Thornton JD, Gunsolley JC. Comparison of debris extruded apically in straight canals: conventional filing versus profile. 04 Taper series 29. J Endod 1998;24:18 –22. 8. Hinrichs RE, Walker WA, Schindler WG. A comparison of apically extruded debris using handpiece-driven nickel-titanium instrument systems. J Endod 1998;24:102– 6. 9. Reddy SA, Hicks ML. Apical extrusion of debris using two hand and two rotary instrumentation techniques. 1998;24:180 –3. 10. Ferraz CC, Gomes NV, Gomes BP, Zaia AA, Teixeira FB, Souza-Filho FJ. Apical extrusion of debris and irrigants using two hand and three engine-driven instrumentation techniques. Int Endod J 2001;34:354 – 8. 11. Lambrianidis T, Tosounidou E, Tzoanapoulou M. The effect of maintaining apical patency on periapical extrusion. J Endod 2001;27:696 – 8. 12. Goldberg F, Massone EJ. Patency file and apical transportation: an in vitro study. J Endod 2002;28:510 –1. 13. Schneider SW. A comparison of canal preparations in straight and curved canals. Oral Surg 1971;32:271–5. 14. Cohen S, Richard CB. Pathways of the pulp, 6th ed. St. Louis, MO: Mosby, 1994:193. 15. Weiger R, John C, Geigle H, Lo¨st C. An in vitro comparison of two modern apex locators. J Endod 1999;25:765– 8. 16. VandeVisse JE, Brilliant JD. Effect of irrigation on the production of extruded material at the root apex during instrumentation. J Endod 1975;1:243– 6. 17. Negm MM. Intracanal use of a corticosteroid-antibiotic compound for the management of posttreatment endodontic pain. Oral Surg Oral Med Oral Pathol 2001;92:435–9. 18. Nusstein JM, Reader A, Beck M. Effect of drainage upon access on postoperative endodontic pain and swelling in symptomatic necrotic teeth. J Endod 2002;28:584 – 8. 19. Ørstavik D, Haapasalo M. Disinfection by endodontic irrigants and dressings of experimentally infected dentinal tubules. Endod Dent Traumatol 1990;6:142–9. 20. Zehnder M, Kosicki D, Luder H, Sener B, Waltimo T. Tissue-dissolving capacity and antibacterial effect of buffered and unbuffered hypochlorite solutions. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2002;94:756 – 62. 21. Izu KH, Thomas SJ, Zhang P, Izu AE, Michalek S. Effectiveness of sodium hypochlorite in preventing inoculation of periapical tissues with contaminated patency files. J Endod 2004;30:92– 4. 22. Pashley EL, Birdsong NL, Bowman K, Pashley DH. Cytotoxic effects of NaOCl on vital tissue. J Endod 1985;11:525– 8. 23. Reeh ES, Messer HH. Long-term paresthesia following inadvertent forcing of sodium hypochlorite through perforation in maxillary incisor. Endod Dent Traumatol 1989; 5:200 –3. 24. Hu¨lsmann M, Hahn W. Complications during root canal irrigation-literature review and case reports. Int Endod J 2000;33:186 –93. 25. Hales JJ, Jackson CR, Everett AP, Moore SH. Treatment protocol for the management of a sodium hypochlorite accident during endodontic therapy. Gen Dent 2001;49: 278 – 81. 26. Tronstad L. Tissue reactions following apical plugging of the root canal with dentin chips in monkey teeth subjected to pulpectomy. Oral Surg Oral Med Oral Pathol 1978;45:297–304. 27. Holland R, Souza V, Nery MJ, Mello W, Bernabe PF, Otoboni FJA. Tissue reactions following apical plugging of the root canal with infected dentin chips. A histologic study in dogs’ teeth. Oral Surg Oral Med Oral Pathol 1980;49:366 –9. 28. Kayaoglu G, Ørstavik D. Virulence factors of Enterococcus faecalis: relationship to endodontic disease. Crit Rev Oral Biol Med 2004;15:308 –20. 29. Debelian GJ, Olsen I, Tronstad L. Bacteremia in conjunction with endodontic therapy. Endod Dent Traumatol 1994;11:142–9.
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