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Effect of irrigation on the production of extruded material at the root apex during instrumentation
E f f e c t of i r r i g a t i o n o n t h e p r o d u c t i o n of e x t r u d e d m a t e r i a l a t t h e r o o t a p e x during instrumentation Jack E. VandeVisse, DDS, and I. David Brilliant, DDS, MS, Columbus, Ohio
The effect of i r r i q a t i o n o n t h e p r o d u c t i o n of e x t r u d e d m a t e r i a l at the r o o t a p e x d u r i n q s t a n d a r d instrumentation was studied with the u s e of teeth s t o r e d in 10% Formalin. The canals that were i n s t r u m e n t e d in t h e p r e s e n c e of an irriqatinq solution all showed c o l l e c t i b l e a m o u n t s of e x t r u d e d m a t e r i a l . I n s t r u m e n t a t i o n of c a n a l s w i t h o u t a n i r r i q a n t d i d not produce collectible extruded material, The prevention of pain during root canal treatment is a prime consideration to both dentist and patient. Adequate local anesthetics eliminate most of the pain during treatment, but considerable discomfort is occasionally experienced after endodontic instrumentation. The incidence of this pain has been reported as 21% by Ingle and Zeldow,I 40% by Seltzer and others, 2 and 25% by Clem. 3 Pain after endodontic instrumentation is usually due to periapical inflammation. 4 During the biomechanical instrumentation of the root canal, necrotic debris, dentin, pulp fragments, microorganisms, or irrigant
may be forced into the periapical tissue. This extruded material may then provoke an inflammatory reaction. 4 In any event, root canal instrumentation should be performed in a manner that minimizes the amount of material extruded into the periapical tissue. A review of literature showed that no studies have been undertaken to determine which procedures might minimize the amount of material extruded into the periapex. There have been suggestions by Luks ~ and Ingle 6 that a reamer is less likely to force debris through the apex. Grossman 7 and Heuer s advocate thorough irrigation before instrumentation to dilute the noxious fluids from the confines of the root canal. Grossman has said that when "moist infected pulp tissue is present in the apical third of the root canal, the root canal instrument, acting as a plunger, is likely to force some of the infected material through the apical foramen because of the moisture ahead of it. ''7 It would seem that any column of moisture might facilitate the extrusion of material through the apical foramen. The purpose of this study was to
determine whether the presence of the irrigating solution affects the amount of material extruded from the apex during standard instrumentation.
Methods and M a t e r i a l s Sixty-four root canals were used in the study. The teeth were stored in Formalin to simulate necrotic pulp conditions. A pilot study showed that in the presence of various irrigating solutions, both reamers and files would produce extruded material at the apical foramen. Files then were used exclusively in an attempt to standardize the instrumentation procedure. The irrigant was 5.25% sodium hypochlorite. The 64 canals were divided into two groups. Each group contained eight maxillary central incisors, eight maxillary canines, eight palatal canals of maxillary first and second molars, and eight distal canals of mandibular first and second molars. Standard access to the canals was gained in the usual manner by using a no. 4 round bur at high speed. The first group of 32 canals was treated without irrigation. A no. 10 or no. 15 file was extended just through the apical foramen and visual-
243
JOURNAL OF ENDODONTICS ] VOL 1, NO 7, JULY 1975
ized. The apex was enlarged to a no. 25 file at that working length to ensure apical patency. This working length was recorded, and the canals were then enlarged ,with a quarter-turn pull action at a working length 1 mm short of the apical foramen. The maxillary anterior teeth were enlarged to no. 70. The palatal and distal canals of the molars were enlarged to no. 60. If a file was used more than once in a canal, the flutes were cleaned by counterrotating the file in a cotton roll before reinsertion into the canal. The second group of 32 teeth was instrumented in the same manner as the first group, except that 5.25% sodium hypochlorite irrigating solution was used. The canals were flushed with the irrigant after the access preparation and after every third instrument. The irrigation solution was maintained in the pulp chamber; a total of 5 ml was used during each canal preparation. The root apices were observed during instrumentation for the presence of extruded material. When present in collectible amounts, the extruded material was gathered on a waxed weighing paper. All samples were simultaneously air-dried for 24 hours. The extruded material was then weighed on an analytical beam balance.*
Table 1 9 Amounts of extruded material collected from the apices of 32 teeth prepared without irrigating solution.
Canal length (mm)
Amount of extruded material
Maxillary central incisors
27 25 24 26 25 22 20 17
NC NC NC NO NO NO NO NO
Maxillary canines
34 32 30 31 30 30 28 25
NC NC NC NO NO NO NO NO
Palatal roots of maxillary molars
25 24 21 22 21 21 20 20
NC NC NC NO NO NO NO NO
Distal roots of mandibular molars
23 22 21 21 22 22
NC NC NC NC NO NO NO
18 18
Results
All of the teeth were observed during instrumentation for the presence of extruded material. When extruded material was collectible, it was gathered and weighed. There was no collectible material extruded from any of the teeth instrumented without irrigation solution (Table 1). The canals prepared in the presence of the irrigating solution (group 2) all showed some extruded material (Table 2). The amount of extruded material ranged from 0.184 to 0.626 mg in weight. 244
NO
NO, extruded material not observed; NC, extruded material not collectible. Note:
The following observations were made during instrumentation: ---The no. 50 file was crucial in the irrigated series of canals. It was at this size that significant amounts of material began to be extruded from the apex. - - I t was relatively more difficult to instrument dry canals than wet canals. In several instances, the instruments jammed and, occasionally, instrument
separation occurred. - - T h e canal could be instrumented to the last size without irrigation and no extruded material was observed. However, if the canal was then irrigated and reinstrumented with the last instrument, material was extruded. Discussion
In this study, 32 canals were instrumented without irrigation. At no
JOURNAL OF ENDODONTICS I VOL I, NO 7, JULY 1975
Table 2 9 Amounts oi extruded materials collected |tom the apices of 32 teeth prepared in the presence of the irrigating solution.
Canal length (ram)
Weight of extruded material (mg)
Maxillary central incisors
32 30 28 25 25 24 23 18
0.523 0.429 0.322 0.315 0.294 0.231 0.202 0.184
Maxillary canines
33 31 30 30 30 29 27 24
0.626 0.449 0.437 0.415 0.413 0.409 0.395 0.218
Palatal roots of maxillary molars
27 25 24 25 24 21 20 20
0.592 0.503 0.498 0.487 0.421 0.412 0.399 0.396
Distal roots of mandibular molars
24 25 26 23 23 22 21 20
0.550 0.522 0.520 0.497 0.453 0.374 0.301 0.293
Note: The teeth are presented in each group according to decreasing specimen weights.
time was material extruded in sufficient amounts to ,be collected. In most instances, absolutely no extruded material was produced. I n contrast, it was observed that by irrigating and instrumenting 32 similar teeth and by keeping the pulp chamber filled with the irrigant, extruded material was always produced. The root canal instrument probably acts like a plunger in the root canal, as Gross-
man suggested. 7 DentinaI filings, necrotic debris, and irrigant might then be forced into the periapical tissues. The no. 50 file was crucial in irrigated canals of this study. It was at this size that the extruded material began to appear in significant quantities. It was interesting that the no. 50 file was usually the first instrument to meet a large amount of mechanical resistance.
The length of the canal seemed to strongly influence the amount of extruded material. The amount of material extruded increased in proportion to the length of the canal. The effect of canal length was noted during instrumentation and the data tend to support this observation. This project does not, however, contain a sufficient quantity of data to verify the effect of canal length. The study shows the tendency for the amount of extruded material to be directly related to canal length. This is an area that deserves further study. Seltzer 4 has said that dentinal filings could be a source of periapical inflammation. In addition, the necrotic debris and the irrigant can also act as a periapical irritant. It would seem logical to assume that reducing the amount or irritational quality of the extruded material would be desirable. One method of reducing extruded material as demonstrated by this study, would be to instrument the canal under dry conditions. This does not seem to be a reasonable alternative because of some of the problems encountered during dry instrumentation. One of these problems is that more effort is required to instrument the canal without the benefit of the lubrication effect of the irrigant. It also was much easier to plug up the canal with sludge and nearly block it without irrigation. Further, it was observed that the instruments tended to bind in a dry canal and instrument separation occasionally occurred. Instrument breakage was not a problem encountered in any of the wet canals. It would seem, then, that irrigation is desirable to efficiently effect canal preparation. Another method of reducing the periapical inflammatory response would .be to decrease the toxicity of the extruded material. Since the irrigation solution is a component of the extruded material, reducing its toxicity 245
JOURNAL OF ENDODONTICS ] VOL 1, NO 7, JULY 1975
would seem advantageous. Spangberg and associates 9 have suggested the use of 0.5% sodium hypochlorite as an irrigating solution. They say, "The advantage of this solution is that it dissolves necrotic but not vital tissue. Simultaneously, the toxicity is reduced considerably and the antimicrobial effect is retained for all bacteria commonly present in necrotic cases. ''~ Thus, by careful selection of an irrigant, the degree of irritation that is due to mechanically extruded material might be reduced. Some concern on our part must be expressed in extrapolating this data to an in vivo situation. The naturally occurring apical foramen was observed to be variable in size; it rarely coincided with the root apex. Kuttler, 10 in a study of 402 extracted teeth, reported that the average apical foramen was about 520/zm (micrometers) in the 18- to 25-year age group. This is roughly twice the diameter of the apical foramen created by the no. 25 file in this study. Yet, most patients experience little or no discomfort after instrumentation. Bender and others 11 reported that after ten minutes of vigorous manipulation of a file within the root canal in the presence of saliva, no positive blood cultures were detected in 25 teeth providing instrumentation was not performed beyond
246
the root apex. Perhaps the periapical tissues themselves provide a natural barrier that prevents the extrusion of the pulpal material. Summary
The effect of irrigation on the production of extruded material at the root apex during standard instrumentation was studied using teeth stored in Formalin. The canals instrumented in the presence of irrigating solution all showed collectible amounts of extruded material. Conversely, instrumentation of canals without an irrigant did not produce collectible extruded material. A further study would use different instrumentation sequences and techniques to determine how to minimize the amount of extruded material. *Sartorius-Werke, Gottingen, Germany. This article was submitted in partial fulfillment of the requirements for a certificate program, department of endodontics, the Ohio State University College of Dentistry. Dr. VandeVisse is in private practice, Pittsburg, Pa., and Dr. Brilliant is director, graduate section, department of endodontics, Ohio State University. Requests for reprints should be directed to Dr. J. David Brilliant, Department of Endodontics, Ohio State University, College of Dentistry, 305 W 12th Ave, Columbus, Ohio 43210.
References
1. Ingle, J.I., and Zeldow, B.J. A clinical-laboratory evaluation of three intracanal antibacterial agents, In Translations of Second International Conference on Endodontics, L. I. Grossman (ed.) Philadelphia, 1958, pp 81-95, 2. Seltzer, S.; Bender, I.B.; and Ehrenreich, J. Incidence and duration of pain following endodontic therapy. Relationship to treatment with sulfonamides and to other factors. Oral Surg 14:74 Jan 1961. 3. Clem, W.H. Posttreatment endodontic pain. JADA 81:1166 Nov 1970. 4. Seltzer, S. Endodontology; biologic considerations in endodontic procedures. New York, McGraw-Hilt Co., 1971, p 258. 5. Luks, S. An analysis of root canal instruments. JADA 58:85 March 1959. 6. Ingle, J. Endodontics. Philadelphia, Lea & Febiger, 1965, p 171. 7. Grossman, L.I. Endodontic practice, ed 8. Philadelphia, Lea & Febiger, 1974, p 164. 8. Heuer, M.A. The biomechanics of endodontic therapy. Dent Clin North Am 13:341 July 1963. 9. Spangberg, L.; Engstrom, B.; and Langeland, K. Biologic effects of dental materials. Toxicity and antimicrobial effect of endodontic antiseptics in vitro. Oral Surg 36:856 Dec 1973. 10. Kuttler, Y. Microscopic investigation of root apexes. JADA 50:544 May 1955.
11. Bender, I.B.; Seltzer, S.; and Yermish, M. The incidence of bacteremia in endodontic manipulation. Oral Surg 13: 350 March 1960.
The effect of i r r i q a t i o n o n t h e p r o d u c t i o n of e x t r u d e d m a t e r i a l at the r o o t a p e x d u r i n q s t a n d a r d instrumentation was studied with the u s e of teeth s t o r e d in 10% Formalin. The canals that were i n s t r u m e n t e d in t h e p r e s e n c e of an irriqatinq solution all showed c o l l e c t i b l e a m o u n t s of e x t r u d e d m a t e r i a l . I n s t r u m e n t a t i o n of c a n a l s w i t h o u t a n i r r i q a n t d i d not produce collectible extruded material, The prevention of pain during root canal treatment is a prime consideration to both dentist and patient. Adequate local anesthetics eliminate most of the pain during treatment, but considerable discomfort is occasionally experienced after endodontic instrumentation. The incidence of this pain has been reported as 21% by Ingle and Zeldow,I 40% by Seltzer and others, 2 and 25% by Clem. 3 Pain after endodontic instrumentation is usually due to periapical inflammation. 4 During the biomechanical instrumentation of the root canal, necrotic debris, dentin, pulp fragments, microorganisms, or irrigant
may be forced into the periapical tissue. This extruded material may then provoke an inflammatory reaction. 4 In any event, root canal instrumentation should be performed in a manner that minimizes the amount of material extruded into the periapical tissue. A review of literature showed that no studies have been undertaken to determine which procedures might minimize the amount of material extruded into the periapex. There have been suggestions by Luks ~ and Ingle 6 that a reamer is less likely to force debris through the apex. Grossman 7 and Heuer s advocate thorough irrigation before instrumentation to dilute the noxious fluids from the confines of the root canal. Grossman has said that when "moist infected pulp tissue is present in the apical third of the root canal, the root canal instrument, acting as a plunger, is likely to force some of the infected material through the apical foramen because of the moisture ahead of it. ''7 It would seem that any column of moisture might facilitate the extrusion of material through the apical foramen. The purpose of this study was to
determine whether the presence of the irrigating solution affects the amount of material extruded from the apex during standard instrumentation.
Methods and M a t e r i a l s Sixty-four root canals were used in the study. The teeth were stored in Formalin to simulate necrotic pulp conditions. A pilot study showed that in the presence of various irrigating solutions, both reamers and files would produce extruded material at the apical foramen. Files then were used exclusively in an attempt to standardize the instrumentation procedure. The irrigant was 5.25% sodium hypochlorite. The 64 canals were divided into two groups. Each group contained eight maxillary central incisors, eight maxillary canines, eight palatal canals of maxillary first and second molars, and eight distal canals of mandibular first and second molars. Standard access to the canals was gained in the usual manner by using a no. 4 round bur at high speed. The first group of 32 canals was treated without irrigation. A no. 10 or no. 15 file was extended just through the apical foramen and visual-
243
JOURNAL OF ENDODONTICS ] VOL 1, NO 7, JULY 1975
ized. The apex was enlarged to a no. 25 file at that working length to ensure apical patency. This working length was recorded, and the canals were then enlarged ,with a quarter-turn pull action at a working length 1 mm short of the apical foramen. The maxillary anterior teeth were enlarged to no. 70. The palatal and distal canals of the molars were enlarged to no. 60. If a file was used more than once in a canal, the flutes were cleaned by counterrotating the file in a cotton roll before reinsertion into the canal. The second group of 32 teeth was instrumented in the same manner as the first group, except that 5.25% sodium hypochlorite irrigating solution was used. The canals were flushed with the irrigant after the access preparation and after every third instrument. The irrigation solution was maintained in the pulp chamber; a total of 5 ml was used during each canal preparation. The root apices were observed during instrumentation for the presence of extruded material. When present in collectible amounts, the extruded material was gathered on a waxed weighing paper. All samples were simultaneously air-dried for 24 hours. The extruded material was then weighed on an analytical beam balance.*
Table 1 9 Amounts of extruded material collected from the apices of 32 teeth prepared without irrigating solution.
Canal length (mm)
Amount of extruded material
Maxillary central incisors
27 25 24 26 25 22 20 17
NC NC NC NO NO NO NO NO
Maxillary canines
34 32 30 31 30 30 28 25
NC NC NC NO NO NO NO NO
Palatal roots of maxillary molars
25 24 21 22 21 21 20 20
NC NC NC NO NO NO NO NO
Distal roots of mandibular molars
23 22 21 21 22 22
NC NC NC NC NO NO NO
18 18
Results
All of the teeth were observed during instrumentation for the presence of extruded material. When extruded material was collectible, it was gathered and weighed. There was no collectible material extruded from any of the teeth instrumented without irrigation solution (Table 1). The canals prepared in the presence of the irrigating solution (group 2) all showed some extruded material (Table 2). The amount of extruded material ranged from 0.184 to 0.626 mg in weight. 244
NO
NO, extruded material not observed; NC, extruded material not collectible. Note:
The following observations were made during instrumentation: ---The no. 50 file was crucial in the irrigated series of canals. It was at this size that significant amounts of material began to be extruded from the apex. - - I t was relatively more difficult to instrument dry canals than wet canals. In several instances, the instruments jammed and, occasionally, instrument
separation occurred. - - T h e canal could be instrumented to the last size without irrigation and no extruded material was observed. However, if the canal was then irrigated and reinstrumented with the last instrument, material was extruded. Discussion
In this study, 32 canals were instrumented without irrigation. At no
JOURNAL OF ENDODONTICS I VOL I, NO 7, JULY 1975
Table 2 9 Amounts oi extruded materials collected |tom the apices of 32 teeth prepared in the presence of the irrigating solution.
Canal length (ram)
Weight of extruded material (mg)
Maxillary central incisors
32 30 28 25 25 24 23 18
0.523 0.429 0.322 0.315 0.294 0.231 0.202 0.184
Maxillary canines
33 31 30 30 30 29 27 24
0.626 0.449 0.437 0.415 0.413 0.409 0.395 0.218
Palatal roots of maxillary molars
27 25 24 25 24 21 20 20
0.592 0.503 0.498 0.487 0.421 0.412 0.399 0.396
Distal roots of mandibular molars
24 25 26 23 23 22 21 20
0.550 0.522 0.520 0.497 0.453 0.374 0.301 0.293
Note: The teeth are presented in each group according to decreasing specimen weights.
time was material extruded in sufficient amounts to ,be collected. In most instances, absolutely no extruded material was produced. I n contrast, it was observed that by irrigating and instrumenting 32 similar teeth and by keeping the pulp chamber filled with the irrigant, extruded material was always produced. The root canal instrument probably acts like a plunger in the root canal, as Gross-
man suggested. 7 DentinaI filings, necrotic debris, and irrigant might then be forced into the periapical tissues. The no. 50 file was crucial in irrigated canals of this study. It was at this size that the extruded material began to appear in significant quantities. It was interesting that the no. 50 file was usually the first instrument to meet a large amount of mechanical resistance.
The length of the canal seemed to strongly influence the amount of extruded material. The amount of material extruded increased in proportion to the length of the canal. The effect of canal length was noted during instrumentation and the data tend to support this observation. This project does not, however, contain a sufficient quantity of data to verify the effect of canal length. The study shows the tendency for the amount of extruded material to be directly related to canal length. This is an area that deserves further study. Seltzer 4 has said that dentinal filings could be a source of periapical inflammation. In addition, the necrotic debris and the irrigant can also act as a periapical irritant. It would seem logical to assume that reducing the amount or irritational quality of the extruded material would be desirable. One method of reducing extruded material as demonstrated by this study, would be to instrument the canal under dry conditions. This does not seem to be a reasonable alternative because of some of the problems encountered during dry instrumentation. One of these problems is that more effort is required to instrument the canal without the benefit of the lubrication effect of the irrigant. It also was much easier to plug up the canal with sludge and nearly block it without irrigation. Further, it was observed that the instruments tended to bind in a dry canal and instrument separation occasionally occurred. Instrument breakage was not a problem encountered in any of the wet canals. It would seem, then, that irrigation is desirable to efficiently effect canal preparation. Another method of reducing the periapical inflammatory response would .be to decrease the toxicity of the extruded material. Since the irrigation solution is a component of the extruded material, reducing its toxicity 245
JOURNAL OF ENDODONTICS ] VOL 1, NO 7, JULY 1975
would seem advantageous. Spangberg and associates 9 have suggested the use of 0.5% sodium hypochlorite as an irrigating solution. They say, "The advantage of this solution is that it dissolves necrotic but not vital tissue. Simultaneously, the toxicity is reduced considerably and the antimicrobial effect is retained for all bacteria commonly present in necrotic cases. ''~ Thus, by careful selection of an irrigant, the degree of irritation that is due to mechanically extruded material might be reduced. Some concern on our part must be expressed in extrapolating this data to an in vivo situation. The naturally occurring apical foramen was observed to be variable in size; it rarely coincided with the root apex. Kuttler, 10 in a study of 402 extracted teeth, reported that the average apical foramen was about 520/zm (micrometers) in the 18- to 25-year age group. This is roughly twice the diameter of the apical foramen created by the no. 25 file in this study. Yet, most patients experience little or no discomfort after instrumentation. Bender and others 11 reported that after ten minutes of vigorous manipulation of a file within the root canal in the presence of saliva, no positive blood cultures were detected in 25 teeth providing instrumentation was not performed beyond
246
the root apex. Perhaps the periapical tissues themselves provide a natural barrier that prevents the extrusion of the pulpal material. Summary
The effect of irrigation on the production of extruded material at the root apex during standard instrumentation was studied using teeth stored in Formalin. The canals instrumented in the presence of irrigating solution all showed collectible amounts of extruded material. Conversely, instrumentation of canals without an irrigant did not produce collectible extruded material. A further study would use different instrumentation sequences and techniques to determine how to minimize the amount of extruded material. *Sartorius-Werke, Gottingen, Germany. This article was submitted in partial fulfillment of the requirements for a certificate program, department of endodontics, the Ohio State University College of Dentistry. Dr. VandeVisse is in private practice, Pittsburg, Pa., and Dr. Brilliant is director, graduate section, department of endodontics, Ohio State University. Requests for reprints should be directed to Dr. J. David Brilliant, Department of Endodontics, Ohio State University, College of Dentistry, 305 W 12th Ave, Columbus, Ohio 43210.
References
1. Ingle, J.I., and Zeldow, B.J. A clinical-laboratory evaluation of three intracanal antibacterial agents, In Translations of Second International Conference on Endodontics, L. I. Grossman (ed.) Philadelphia, 1958, pp 81-95, 2. Seltzer, S.; Bender, I.B.; and Ehrenreich, J. Incidence and duration of pain following endodontic therapy. Relationship to treatment with sulfonamides and to other factors. Oral Surg 14:74 Jan 1961. 3. Clem, W.H. Posttreatment endodontic pain. JADA 81:1166 Nov 1970. 4. Seltzer, S. Endodontology; biologic considerations in endodontic procedures. New York, McGraw-Hilt Co., 1971, p 258. 5. Luks, S. An analysis of root canal instruments. JADA 58:85 March 1959. 6. Ingle, J. Endodontics. Philadelphia, Lea & Febiger, 1965, p 171. 7. Grossman, L.I. Endodontic practice, ed 8. Philadelphia, Lea & Febiger, 1974, p 164. 8. Heuer, M.A. The biomechanics of endodontic therapy. Dent Clin North Am 13:341 July 1963. 9. Spangberg, L.; Engstrom, B.; and Langeland, K. Biologic effects of dental materials. Toxicity and antimicrobial effect of endodontic antiseptics in vitro. Oral Surg 36:856 Dec 1973. 10. Kuttler, Y. Microscopic investigation of root apexes. JADA 50:544 May 1955.
11. Bender, I.B.; Seltzer, S.; and Yermish, M. The incidence of bacteremia in endodontic manipulation. Oral Surg 13: 350 March 1960.