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ePaper created 2017-04-19, 21:15:41 | version 1.38.0
laser_case report Discussion Due to its insidious pathology, the following clinical findings enabled the establishment of the diagnosis of IRR:44 initial absence of bleeding from the root ca- nal confirming a necrotic pulp, normal probing depth (< 3 mm) and the complete resolution of apical radio- lucency after endodontic treatment, followed by the cessation of the progression of resorption. Given that there is insufficient clinical data sup- porting the superiority of any chemical irrigation reg- imen and no guidelines for the management of low-occurrence pathologies such as IRR, case reports may be of special relevance while adequately report- ing new disinfection techniques and their clinical outcomes.3, 45 The present protocol adopted the use of an Er,Cr:YSGG laser and innocuous irrigants (e.g. saline solution as irrigation and distilled water for laser ac- tivation). The decision was primordially based on the assumption that IRR lesions may perforate external root surfaces without being detectable on conven- tional radiographic images,46 and that anatomic vari- ations are known to significantly contribute to the occurrence of sodium hypochlorite accidents.47 While trying to achieve significant bacterial reduc- tions, our protocol contrast with that recently re- ported by Christo et al. which used low concentra- tions of NaOCl and a Er,Cr:YSGG laser-activation technique. In fact, this protocol has been shown not to improve the antibacterial effects of NaOCl48 and, therefore, the activation of NaOCl may seem inade- quate for the management of such conditions. In accordance, it was shown that the use of Er,Cr:YSGG laser with relatively high output powers to activate irrigants such as NaOCl or EDTA may result in a high magnitude of pressure changes capable to induce ir- rigants extrusion during laser-activated irrigation.49 In order to obtain adequate microbial control cal- cium hydroxide (CH) is often recommended for the management of IRR lesions.50–52 However, the use of CH as an intra-canal medication consistently fails to present improved clinical outcomes.53–55 In the pres- ent report we may support that CH medication should not be considered crucial as antimicrobial agent and neither as essential to stop the IRR progression. In fact, the decision process for not using CH as intra- canal medication during the endodontic treat- ment of IRR was also supported by the following cri- teria: (1) no irrigation technique is completely able to remove CH from simulated internal root resorption cavities14 and (2) the long-term exposure to CH can cause a significant reduction in the mechanical prop- erties of radicular dentine.56 Due to their biophysical properties, lasers have long been seen as a promising disinfection tool in endodontics. However, each wavelength demon- strates different biophysical interactions with the main radicular dentine components.15 The high ab- sorption coefficients in both water and hydroxyap- atite may justify the selection of the Er,Cr:YSGG la- ser (=2,780 nm) for both smear layer removal and disinfection purposes.18 Conflicting evidence while using other wavelengths can be found consis- tently.57, 58 In the present report, the laser protocol consisted in two irradiations with distilled water in the main canal followed by two irradiations in dry conditions, respectively for smear layer removal and disinfec- tion purposes.42 The rationale was that in wet condi- tions the Er,Cr:YSGG laser can promote beneficial cavitation effects inside the main canal without in- creasing the extrusion of irrigants.38 Moreover, wa- ter-mediated cavitation has been shown to be highly effective for the removal of dentin debris in compar- ison with conventional or passive ultrasonic irriga- Fig. 4: Twelve-month follow-up. Fig. 5: Two-year follow-up. Fig. 6: Three-year follow-up from the mesial direction. Fig. 7: Three-year follow-up from the distal direction. Fig. 4 Fig. 5 Fig. 6 Fig. 7 laser 1_2017 3737