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ePaper created 2016-11-22, 11:57:56 | version 1.38.0
22 Endo Tribune Asia Pacific Edition | 11/2016 TRENDS & APPLICATIONS Endodontics is the dental specialty that is concerned with treating or preventing pulpal pathologies and apical periodontitis. The main objec- tives of endodontic treatment are to clean and disinfect the entire length of the root canal system up to a healthy level.1 When, through metic- ulous treatment, such objectives are achieved, success rates can exceed 94 per cent.2, 3 In pursuit of such results, during endodontic therapy, mechanical preparation is carried out with endodontic instruments and chemical preparation with irri- gating solutions. After cleaning and shaping, en- dodontic filling must be performed to fill three-dimensionally and seal the endodontic space in order to prevent bacterial recontamination, maintaining the sanitation condi- tions achieved through the previ- ous steps. The mechanical prepara- tion of the root canal system is of utmost importance in the process of establishing endodontic saniti- sation.4, 5 It is responsible for phy- sically removing the infected den- tine and, consequently, bacteria located within the dentinal tubules. In addition, it increases the diam- eter and shapes the main canals, facilitating flow of larger volumes of irrigating solutions to the apical third.6, 1 It also creates a favourable conical shape for endodontic filling. Therefore, it directly influences the quality of the disinfection process and, consequently, the prognosis of the case. Procedural errors during me- chanical preparation may make it impossible to achieve the re- quired disinfection levels. Yousuf et al. evaluated 1,748 endodontically treated teeth using digital radiogra- phy and found procedural errors in 32.8 per cent (574 teeth) of them. Transportation of the apical fora- men, whether leading to root per- foration or not, is among the most common errors during endodontic treatment, especially in curved ca- nals.7–9 The Glossary of Endodontic Terms by the American Associa- tion of Endodontists defines “canal transportation” as “Removal of canal wall structure on the outside curve in the apical half of the canal due to the tendency of files to re- store themselves to their original linear shape during canal prepara- tion; may lead to ledge formation and possible perforation.” The inadvertent use of rigid endodontic files, such as stainless steel, especially of larger diameters, without previous examination of the internal dental anatomy as part of the procedure, increases the risk of transportation of the foramen. Insufficient cleaning of canals, especially the apical third, pre- disposes treatment to endodontic failure.10, 11 Transportation of the foramen may not only impair dis- infectionofthecanalsystembydis- abling access to its original trajec- tory, but also irritate the periapex by extruding bacteria and their by-products and derail the ideal apical adjustment of a gutta-percha cone. These technical hindrances due to operational error in the preparation phase can negatively influence apical sealing and appro- priate bacterial control.12 As a result, they worsen the prognosis of the clinical case involved. According to Gluskin et al., transportation of the foramen can be classified into three categories: • Type I represents a minor move- ment of the physiological position of the foramen. • Type II represents a moderate movement of the physiological position of the foramen, resulting in a considerable iatrogenic relo- cation on the external root sur- face. In this type, a larger commu- nication with the periapical space exists. • Type III represents a severe move- ment of the physiological position of the foramen and the canal, re- sulting in a significant iatrogenic relocation. Treatment of apical transporta- tion cases can be performed accord- ing to various clinical approaches. Canals with Type I transportation can usually be cleaned and filled. Type II may be filled after the appli- cation of an apical barrier to control bleeding and to serve as a physical shield to prevent extrusion of the endodontic filling material. In these situations, placing an apical capwithmineraltrioxideaggregate (MTA), followed by conventional en- dodontic filling, can be considered. However, in clinical cases with api- cal transportation of Type III, it is generally not possible to achieve cleaning, disinfection and proper filling. Thus, these steps should be performed as well as possible and be followed by an apical microsur- gery to remove the untreated apical region. Clinical case A 55-year-old female patient (American Society of Anesthesiolo- gists Physical Status Class I) visited the dental office complaining about spontaneous, constant pain, exac- erbated during mastication and apical palpation in the region of teeth #13 and #11, which had been treated endodontically over the course of the last three months. The patient reported that she did not feel pain before the initial endo- dontic treatment began. After the first endodontic session, during which teeth #13 and #11 were treated at the same time, the pain began and had worsened after the third day. On the fourth day, the patient had to receive intravenous dipyrone and ketoprofen to control the pain. Concurrent with the sys- temic medication, an occlusal ad- justment was performed. After two days, the pain returned and the patient went to another dentist, who administered sodium dipyrone 500 mg/ml every four hours and nimesulide 100 mg every 12 hours orally for seven days. The pain de- creased, but did not cease. Two days after systemic medi- cation ended, the patient again felt pain. She went to a third dental pro- fessional, who initiated endodontic retreatment of teeth #11 and #13. However, the therapy performed was not able to control the pain effectively. After four days, the patient also began showing febrile conditions. It was reported that, in none of the endodontic procedures performed, was absolute sealing achieved. Clinical examination estab- lished endodontic access at teeth #13 and #11. Inadequate geometric Fig. 1: Initial clinical view of tooth #11.—Fig. 2: Initial clinical view of tooth #13.—Fig. 3: Initial radiograph.—Fig. 4: Tomographic image demonstrating the transportation of the foramen of tooth #11.— Fig. 5: Tomographic image demonstrating the transportation of the foramen of tooth #13.—Fig. 6: Clinical image captured under the operating microscope showing the original canal trajectory and apical deviation of tooth #11.—Fig. 7: Radiograph of an endodontic file positioned in the apical deviation of tooth #11. 4 5 6 Fig. 8: Apical cap with MTA Repair HP.—Fig. 9: Canal drying of tooth #12 with SurgiTip (MANUFACTURER).—Fig. 10: Retrofilling of tooth #12 with MTA Repair HP.— Fig. 11: Immediate postoperative radiograph.—Fig. 12: Control radiograph five months later of the periapical repair. Apical transportation Microsurgical handling of a procedural error during apical mechanical preparation Prof. Leandro A.P. Pereira, Brazil 1 2 3 7 8 9 10 11 456 123 891011