Written by Filippo Santarcangelo, DDS, and Arnaldo Castellucci, MD, DDS Monday, 18 March 2013 08:59
In order to perform successful endodontic therapy, the clinician should be able to shape, clean, and fill the root canal system in 3 dimensions.1 Canal preparation in teeth with irreversible pulpitis allows mechanical debridement to be performed, leading to the removal of a great deal of the pulp tissue. The same preparation creates space for the easy delivery of irrigants (eg, sodium hypochlorite [NaOCl]), which dissolves tissue/organic compounds of the smear layer and thus completes the emptying of the root canal system chemically.2 Canal instruments and hypochlorite therefore operate together to remove the organic content of the root canal system in what is called chemomechanical canal preparation.3 Unfortunately, there are limitations to doing this because the root canal system is a very difficult environment in which to operate.4 Canal shaping is unable to reach some areas and the canals remain untouched by the instruments, so no matter what technique is used, about half of the canal space remains untreated.5-7 Sodium hypochlorite also has some limitations dictated by anatomical features: the narrower and more curved the canals, the more difficult it is to technically distribute it in the best possible way. There is also a risk of pulp compaction in the last few millimeters of the canal during the negotiation phase, which may lead to blockages that are difficult to break through and remove.8
This article describes a novel technique that may help the operator with chemomechanical debridement of the pulp tissue, envisaging the total and simultaneous removal of the pulp tissue in multirooted teeth.
A simple clinical observation underlies the technique of simultaneous and complete removal of the pulp tissue in multirooted teeth with irreversible pulpitis: it is easier to completely remove the pulp tissue with a barbed broach in wide and straight canals (palatal canals of premolars and upper molars, distal canals of lower molars) than in narrow and curved canals (buccal canals of premolars and upper molars and mesial canals of lower molars). The reason for this is that, in the former, the barbed broach can reach further down to engage the pulp tissue better; whereas, in the latter, it gives poor results as the pulp snaps without being completely removed and the barbed broach can easily break.
In multirooted teeth, the organic tissue of the pulp chamber provides a link with the pulp in the various canals. If the operator engages the pulp in the wider canal with the barbed broach, leaving the tissue in the pulp chamber untouched, it could bring with it the tissue located in the narrower and more curved canals.
It is really important to assess the preoperative radiograph, as it gives us information on the size of the pulp chamber and consequently on the amount of pulp tissue present. Teeth with a large pulp chamber space are more suitable for receiving this procedure than those with a calcified or very narrow pulp chamber.
Some guidelines must be followed to ensure the complete removal of the pulp tissue.
During access cavity preparation, the operator should carefully remove the pulp chamber roof with ultrasonic tips suitably cooled with air, under direct visual control and without damaging the pulp chamber tissue in any way. Then, insert a first barbed broach (generally extra-fine or fine) in the wider canal (palatal or distal canal) as far as possible without forcing it and then turn it a full 360°. After this, position a second slightly smaller broach or one the same size in this canal and then wind it around the first one 4 to 5 times. The second broach has the job of not only engaging the pulp in the same canal more firmly, but also and more importantly than in the pulp chamber. In a few seconds, the chamber pulp will be wound around the 2 broaches, bringing with it the tissue contained in the other canals as well.
At this point the operator will feel the instruments engaging firmly and will particularly feel that the barbs are set and that there is resistance from the whole pulp tissue mass. This is the right time to pull out the broaches with the organic content of the root canal system. After the pulp tissue has been patiently unwound from the barbed broaches, it can be observed, more often than not, in its entirety.
Case 1: Diagnosis and Treatment Planning
A 35-year-old female patient was referred to the dental office of one of the authors for endodontic treatment of the left upper first premolar, with history of pain. The general anamnesis contained no abnormal data. Her dental history showed episodes of spontaneous pain. She also complained of episodes of sharp pain while chewing. On inspection with 4.5x magnification prismatic loupes (Zeiss Eyemag Pro S [Carl Zeiss Meditec]), the tooth showed a crack running mesiodistally on the occlusal surface. The tooth was painful to percussion and responsive to sensitivity tests (cold, hot, electric). The pattern of probing was normal and a bite test using a cotton roll was performed.
The patient was asked to clench on a cotton roll placed directly over the tooth, and she felt a sharp pain. A few minutes later, spontaneous pain started. The preoperative diagnostic radiograph did not reveal a carious lesion or signs of periapical radiolucency (Figure 1). The clinical diagnosis of cracked tooth syndrome with irreversible pulpitis was made, and endodontic treatment was scheduled.
After local anesthesia and rubber dam isolation, an adequate endodontic access was made and the simultaneous removal of the whole pulp tissue performed, as recommended in this novel technique. Two barbed broaches, an extrafine and a fine one (DENTSPLY Maillefer), were used to remove the pulp tissue (Figures 2 and 3). On inspection, the crack did not involve the pulp chamber floor. The working lengths were established with an electronic apex locator and confirmed radiographically. The canals were instrumented with ProFile GT Series X (DENTSPLY Tulsa Dental Specialties) Ni-Ti rotary instruments in a crown-down technique. Irrigation was performed with copious amounts of 5% NaOCl and 17% ethylenediaminetetraacetic (EDTA) acid, and in the meantime a cone-fit x-ray was taken (Figure 4). The canals were finally washed with sterile saline, dried with sterile paper points, and filled with GT gutta-percha cones (DENTSPLY Tulsa Dental Specialties) and Kerr Pulp Canal Sealer (SybronEndo). The continuous wave of condensation technique with the System B Heat-Source (SybronEndo) was used to condense the gutta-percha cones, and the Obtura II system (Obtura Spartan) was used for the backfilling (Figure 5).9
The patient did not suffer from postoperative complications, and correct restoration was carried out in a separate appointment. The patient was recalled every 6 months for the first 2 years, and after that, every year in the checkups, the tooth was asymptomatic and the radiographs showed no radiolucency (Figures 6 and 7).
|Figure 1. Preoperative radiograph of a left upper first premolar with no carious lesion and no signs of periapical radiolucency.||Figure 2. A second barbed broach is inserted in the same canal as far as possible without forcing it and is turned around the first one several times (4 to 5 times).|
|Figure 3. Once the barbed broaches have been removed with the pulp tissue attached to them, the tissue is unwound and the organic content of the root canal system (pulp from the palatal and buccal canals along with the pulp chamber content) can be seen in its entirety.||Figure 4. Cone-fit radiograph.|
|Figure 5. Postoperative radiograph. Root canals were filled with gutta-percha and sealer.||Figure 6. Twelve-month recall radiograph showing the maintenance of the normal status of the periradicular tissue.|
|Figure 7. Two-year recall radiograph showing the maintenance of the normal status of the periradicular tissue.||Figure 8. Preoperative radiograph of a right upper first molar with no carious lesion and no signs of periapical radiolucency.|
|Figure 9. Two barbed broaches at work.||Figure 10. The organic content of the root canal system can be seen in its entirety.|
Case 2: Diagnosis and Treatment Planning
A 40-year-old female patient was referred to the dental office of one of the authors for endodontic treatment of the right upper first molar. The general anamnesis contained no abnormal data. In her dental history, episodes of spontaneous pain were found. On examination, the tooth showed an extensive composite restoration on the occlusal surface. The tooth was not painful to percussion and not responsive to a cold test, but it was very responsive to a hot test, developing spontaneous pain. The pain spread throughout the entire upper part of face to the frontoparietal area. The preoperative diagnostic radiograph of the upper right first molar revealed a deep restoration close to the pulp with no signs of periapical radiolucency (Figure 8). The clinical diagnosis of pulpitis was made, and endodontic treatment was scheduled.
After local anesthesia was given and rubber dam isolation was secured, all the composite restoration was removed. Next, an adequate endodontic access opening was made and the simultaneous removal of the whole pulp tissue performed, as recommended in this novel technique (Figure 9).
Two barbed broaches, an extrafine and a fine one, were used to remove the pulp tissue (Figure 10). On inspection with Zeiss 4.5x magnification prismatic loupes, the pulp chamber floor showed 4 orifices corresponding to 4 root canals: MB1, MB2, DB, and palatal. The working lengths were established with an electronic apex locator, and K-files were used to confirm them radiographically (Figures 11 and 12). As in case 1 above, the canals were instrumented with Ni-Ti rotary instruments in a crown-down technique. Irrigation was performed with copious amounts of 5% NaOCl and 17% EDTA acid.
The canals were finally washed with sterile saline, dried with sterile paper points, and filled with GT gutta-percha cones and pulp sealer. The continuous wave of condensation technique with the System B Heat-Source was used to condense the gutta-percha cones, and the Obtura II system was employed for the backfilling (Figure 13).
The patient did not report any postoperative pain, and received appropriate coronal restoration one week later. The checkup at one year showed an absence of infection and no radiolucency (Figure 14).
Case 3: Diagnosis and Treatment Planning
A 50-year-old male patient with a noncontributory medical history, was referred to the private office of one of the authors with pain in his left maxillary region. The patient reported that all of his left upper teeth became very sensitive to cold and hot stimuli after undergoing amalgam restoration on the first left molar. He also reported 2 episodes of severe spontaneous pain in that area, but he could not detect the tooth responsible for it. Upon examination, the first upper left molar showed an amalgam restoration on the palatal surface. The tooth was not painful to percussion. Vitality tests (cold, electric pulp test [EPT]) on the affected tooth showed abnormal responses (lingering pain to cold, increased reaction at EPT), indicating that irreversible pulpitis had occurred. Clinical examination of the surrounding teeth did not reveal any useful clinical signs or symptoms. The preoperative diagnostic radiograph of the left molar revealed the amalgam restoration with no signs of periapical radiolucency (Figure 15). The clinical diagnosis of pulpitis was made, and endodontic treatment was scheduled.
|Figure 11. The working lengths of palatal and distobuccal canal were established with an electronic foramen locator, and K-files were used to confirm them radiographically.||Figure 12. The working lengths of MB1 and MB2 were established with an electronic foramen locator, and K-files were used to confirm them radiographically.|
|Figure 13. Postoperative radiograph. Root canals were filled with gutta-percha and sealer.||Figure 14. Twelve-month recall radiograph showing the maintenance of the normal status of the periradicular tissue.|
|Figure 15. Preoperative x-ray of a left upper first molar with no carious lesion and no signs of periapical radiolucency.||Figure 16. The organic content of the root canal system can be seen in its entirety.|
|Figure 17. The working lengths of MB1, palatal, and distobuccal canal were established with an electronic foramen locator, and WaveOne Ni-Ti Files (DENTSPLY Tulsa Dental) were used to confirm them radiographically.||Figure 18. Postoperative x-ray. Root canals were filled with gutta-percha and sealer. MB2, not detected during the procedure, was also filled.|
|Figure 19. Twelve-month recall x-ray showing the maintenance of the normal status of the periradicular tissue.|
After local anesthesia, rubber dam isolation and adequate endodontic access, the simultaneous removal of the whole pulp tissue was performed, as recommended in this novel technique.
Two barbed broaches, an extrafine and a fine one, were used to remove the pulp tissue (Figure 16). Upon inspection with Zeiss 4.5x magnification prismatic loupes, the pulp chamber floor showed 3 orifices corresponding to 3 root canals: MB1, DB, and palatal. MB2 was not found. The working lengths were established with an electronic apex locator, and the canals were instrumented with WaveOne reciprocating files (DENTSPLY Tulsa Dental); then 3 WaveOne Ni-Ti rotary files were used to confirm the working length radiographically (Figure 17). Irrigation was performed with copious amounts of 5% NaOCl and 17% EDTA acid. The canals were finally washed with sterile saline, dried with sterile paper points, and filled with Thermafil (DENTSPLY Tulsa Dental) and AH-Plus cement (DENTSPLY DeTrey GmbH). The postoperative radiograph shows that the MB2, not detected during the procedure, was also filled (Figure 18).
After the treatment the patient reported no postoperative pain and the 12-month recall evidenced no radiolucency (Figure 19).
Effective cleansing and filling of the root canal system play a crucial role in determining the long-term success of canal therapy. In cases of irreversible pulpitis, careful removal of the organic tissue, which is usually performed by canal instruments and NaOCl, is fundamental.
The anatomic complexity of the root canal system makes complete mechanical removal of the organic tissue difficult, and total chemical dissolution also seems to be difficult for the same reasons because there is no certainty of distributing it throughout the root canal system. The possibility of removing all the pulp of multirooted teeth with irreversible pulpitis in one shot could represent a great advantage for the operator as it simplifies canal treatment. Indeed, from a strictly technical viewpoint, the presence of pulp tissue in the apical third may impede the progression of small K-files which normally create a glide path for the rotary instruments; the latter, by shaping the canal, then allows the deep positioning of irrigant releasing systems and of the irrigants themselves.
The pulp tissue can basically operate in 2 ways. First, by deflecting and ruining small files that could create ledges because they cannot follow the canal lumen, if they are repeatedly deviated onto the canal wall. During the therapy of narrow and curved roots, there is often a significant wastage of small files used in the attempt to negotiate the apical third. Furthermore, in some cases, the pulp pierced by the canal instruments may bunch up and plug the apical third: these tissue blockages are extremely difficult to remove.
For these reasons, the pulp may become an insurmountable obstacle in the apical third, which is already narrow and deep. Therefore, if all the pulp can be removed from the canals in one shot, a potential problem can be removed, making it easier for the canal instruments to perform their work and the irrigants to flow. The NaOCl will also have to deal with a much smaller quantity of organic component, and so it will take less time to perform its activity of dissolution. Finally, in the event of more complex anatomy (severe curves, bi- and trifurcations), it would be less difficult to overcome irregular areas of the apical third because they would have been emptied beforehand. In other words, not only the biochemical debridement but also the obturation of these areas would be made easier.
The novel technique described for the simultaneous removal of the whole pulp tissue in multirooted teeth with irreversible pulpitis can help the operator to perform a more effective chemomechanical debridement and consequently a complete obturation. The cases presented herein, treated as described and examined at recall, have all shown radiographic and clinical evidence of healing. This suggests that the technique may be employed in all cases of multirooted teeth with irreversible pulpitis.
- Schilder H. Cleaning and shaping the root canal. Dent Clin North Am. 1974;18:269-296.
- Zehnder M. Root canal irrigants. J Endod. 2006;32:389-398.
- Stewart GG. The importance of chemomechanical preparation of the root canal. Oral Surg Oral Med Oral Pathol. 1955;8:993-997.
- Hess W. Formation of root canals in human teeth. J Natl Dent Assoc. 1921;3:704-725.
- Peters OA, Schönenberger K, Laib A. Effects of four Ni-Ti preparation techniques on root canal geometry assessed by micro computed tomography. Int Endod J. 2001;34:221-230.
- Paqué F, Ganahl D, Peters OA. Effects of root canal preparation on apical geometry assessed by micro-computed tomography. J Endod. 2009;35:1056-1059.
- Paqué F, Balmer M, Attin T, et al. Preparation of oval-shaped root canals in mandibular molars using nickel-titanium rotary instruments: a micro-computed tomography study. J Endod. 2010;36:703-707.
- Buchanan LS. The standardized-taper root canal preparation—Part 3. GT file technique in large root canals with small apical diameters. Int Endod J. 2001;34:149-156.
- Buchanan LS. Continuous wave of condensation technique. Endod Prac. 1998;1:7-18.
Disclosures: Drs. Santarcangelo and Castellucci report no disclosures.
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