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ePaper created 2017-06-15, 09:14:00 | version 1.38.0
| industry Fig. 3a Fig. 3b Fig. 3: Comparison of periapical radiographs before (a) and post treatment (b). a) Dental restorations of mandibular right first and second premolars were lost due to secondary caries. Periapical radiolucency around the root of mandibular right first was seen. b) One-month post treatment. Accessory canals were identified by sealer. complained of toothache. The fracture of the crowns was a result of secondary caries at the cervical portion of premolars. A large apical lesion was observed around the root of the first premolar. A prosthdontic treatment of splinted crowns on the mandibular right first and second premolars with crown lengthening and cast posts was planned due to the patient’s desire to retain teeth. All symptoms subsided after end- odontic treatment was completed. There was radio- graphic evidence of sealer in the apical ramifications. Case 3 (Figs. 4a–c) A 40-year-old woman sought treatment for a labial sinus tract related to the maxillary right first premolar. Extensive pulpal calcification was noticed on the peri- apical radiograph. The gutta-percha cone indicated that the labial sinus tract which appears to originate from a lateral canal. A dilaceration of the apical third and calcification of the canal made access difficult, resulting in a perforation on the mesial aspect of the root. The working length was adjusted and the canal was obturated to this point. A lateral canal was filled with sealer on the distal aspect of the root. The patient returned for follow-up in two weeks. The sinus tract healed and she was asymptomatic. Fig. 4: Comparison of periapical radiographs before treatment (a, b) and two-week post treatment (c). a) Severe canal calcification with apical root dilaceration of maxillary right first premolar was observed. b) Insertion of a gutta-percha cone into the labial sinus tract for diagnosis. The tip of the gutta- percha cone pointed to the lateral surface of the root instead of the root apex. c) A lateral canal was identified Discussion Microbial infection is considered a major cause of endodontic failure. Several studies reported that peri- apical lesions did not develop without bacteria, al- though pulp tissue had been devitalised6,23; therefore, thorough disinfection is strongly recommended be- fore obturation is performed. The complexity and variability of the root canal system make it difficult to achieve ideal goals of endodontic treatment. A laser system which transmits energy through a flexible and small-diameter optical fibre can provide convenient access to root canals. Consequently, direct and indi- rect disinfection by laser possibly takes place while irradiating the inside of root canals. De Andrade AK et al.24 reported laser disinfection is an effective way to decrease bacterial colonies when the mean power of laser exposure was over 3 Watts. The energy of the Nd:YAP laser is powerful enough to eliminate microbes because the average output of the Nd:YAP laser is 10 Watts and the peak power may reach 2.6 kW. Only 0.00015 seconds of laser energy is emit- ted for every pulsed irradiation,25 so the fleeting mo- ment of emission minimises the risk of overheating surrounding tissues and has bactericidal effects by direct contact. Two possibilities may explain the indi- rect disinfection of laser. When the mode of 30 Hz is used in narrow space such as a root canal filled with irrigation solution, shock waves may occur repeatedly and be transmitted into dentinal tubules to kill bacte- ria. Pulsed irradiation causes vibrations in narrow spaces similar to ultrasonic devices.25 This laser energy caused by high frequency emission of the Nd:YAP laser help maintain the integrity of the root because it is not necessary to eliminate excessive contaminated dentin of canal wall. Minimal enlarge- ment is sufficient, if the space can allow 220 µm opti- cal fibre to move passively through the canal. The laser energy also causes temperature of the NaOCl solution to rise resulting in increased efficiency of dissolving organic debris and disinfection in canals.26 This enhanced cleanliness gains space in apical ramifi- cations for sealer placement. by sealer. Fig. 4a Fig. 4b Fig. 4c 28 laser 2 2017