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The aim of the study was to evaluate the impact of kinematics and irrigation protocols on the extrusion of apical debris during removal of different obturation techniques. A total of 144 single‐rooted teeth were instrumented and obturated with Thermafil+AH Plus, Thermafil+AH Plus Bioceramic and single gutta‐percha cone+AH Plus Bioceramic. Samples were divided according to the retreatment kinematics: continuous rotation or Jeni motion. Each sub‐group was subjected to conventional irrigation or irrigation activated by EDDY. Extruded debris was collected in Eppendorf tubes, weighted and retreatment time was digitally recorded. Data were analysed with two‐way ANOVA (p < 0.05). Debris extrusion was not significantly different between all groups. EDDY activation system and CanalPro Jeni required significantly longer time compared with other groups to remove Thermafil+AH Plus and single cone+AH Plus Bioceramic. Within current limitations, obturation technique, irrigation protocol and kinematics tested had no influence on apical extrusion debris, while they significantly impacted the retreatment time. [ABSTRACT FROM AUTHOR]

This study was to determine the effectiveness of diode laser (LI) and ultrasonic (UI)‐activated irrigation with or without a surfactant as adjunct techniques during the retreatment of gutta‐percha and tricalcium silicate‐based sealer (BC) sealer. Forty‐two single‐rooted premolars were instrumented and filled with gutta‐percha and BC sealer, then retreated using NiTi retreatment rotary files. Teeth were randomly divided into three equal groups: Control (manual irrigation), UI and LI groups. Each group was subdivided into 2.5% NaOCl irrigant and ChlorCid™️ Surf subgroups. The amount of material removed following UI and LI was significantly greater than that of manual irrigation (p < 0.0001). However, there was no significant difference between the surfactant subgroups, irrespective of irrigation technique (p = 1.00, p = 0.535, p = 0.805). The use of UI and LI adjuncts to NiTi rotary retreatment techniques showed significant improvement in gutta‐percha with BC sealer removal. However, surfactants had no effect on the efficacy. [ABSTRACT FROM AUTHOR]

We aimed to investigate the in vitro physiologic effects of xylene, chloroform, orange oil and eucalyptus oil solvents for dissolving gutta‐percha on L929 and HOB cell lines; 2.5 and 10 μL mL−1 of these solvents were tested for 24, 48 and 72 h. Gutta‐percha solvents inhibited the proliferation rate of fibroblasts in a dose‐ and time‐dependent manner; however, no inhibition was detected in HOB (evaluated using MTT assay). None of the solvents induced apoptosis/necrosis in HOB cells at ≤2.5 μL mL−1 concentration in contrast to L929 (determined using acridine orange/ethidium bromide dual staining). Each solvent tested reduced the migration rate of both L929 and HOB cell lines in a dose‐dependent manner (evaluated using a scratch assay). Gutta‐percha solvents can damage fibroblast‐rich tissues. Osteoblasts seemed to be more resistant to the tested solvents, and excessive extrusion of solvents from the root canal may also damage the periradicular tissues and reduce the ability to repair. [ABSTRACT FROM AUTHOR]

The aim of this study was to present a new technique for plastic carrier removal in retreatment situations. The gutta‐percha technique that uses plastic carrier obturators is one of the most commonly used; however, removing this core is tedious and time‐consuming. Two clinical cases were performed by an expert in the field of endodontics, to expose this technique, in which a conical ultrasonic tip with an active point and a Hëdstrom hand file allowed the removal of the plastic carrier quickly and effectively. The use of magnification is indispensable for a predictable success with this method. [ABSTRACT FROM AUTHOR]

This study compared the percentage reduction of total obturation materials, gutta‐percha and sealer, using two rotary file systems with/without solvent in retreating C‐shaped root canals and to evaluate the effect of the solvent on instrument separation. C‐shaped root canals were scanned using micro‐CT to identify the root canal morphology and randomly assigned to four groups (n = 12). Retreatment was performed using ProTaper Universal Retreatment (PTUR) or XP‐endo systems with/without solvent. The number of separated instruments were recorded. The samples were scanned pre‐ and post‐retreatment. The percentage reduction of total obturation materials, gutta‐percha and sealer, were calculated. The percentage reduction of gutta‐percha in the PTUR without solvent group was significantly lower than the other groups (P = 0.018). The number of separated instruments in the solvent groups were significantly lower than the no solvent groups (P < 0.05). Solvent increased gutta‐percha removal, when using PTUR and decreased the occurrence of separated instruments for both systems. [ABSTRACT FROM AUTHOR]

In this study, computed tomography (CT) was used to assess three techniques for root canal filling removal. Seventy-five roots of extracted human lower incisors were filled with zinc oxide-eugenol sealer and gutta-percha and separated into three groups before gutta-percha removal (group 1, Gates Glidden burs + K-type hand instrumentation; group 2, K-type reciprocating instrumentation + NSK TEP E16R; group 3, ProTaper rotary instrumentation + NSK NAC E16R). Specimens were CT-scanned before and after filling removal. The mean rate of filling removal was 94.88%. Reciprocating instrumentation was the most effective and manual instrumentation associated with Gates Glidden burs was the least effective technique. Removal rate was significantly different for the three groups according to one-way anova ( P = 0.049). The Tukey test showed a significant difference between groups 1 and 2 ( P = 0.039) only. CT proved to be a reliable method for assessing root filling removal techniques. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the efficacy of supplementary methods to remove the remaining root filling material from root canals. Twenty mandibular single‐rooted teeth were instrumented with Reciproc 25/0.08 and filled with gutta‐percha and AH‐Plus sealer, followed by a micro‐CT scanning. The retreatment procedures were performed, the samples were rescanned and divided into two groups (n = 10) according to the supplementary method: XP‐endo Finisher R and Clearsonic tip. The samples were rescanned and the volume of remaining root filling material was quantified. Data were analysed statistically (P < 0.05). The amount of filling material removed after supplementary methods was higher compared with retreatment procedure (P < 0.05). XP‐endo Finisher R promoted a greater percentage of filling materials reduction in the entire root canal and apical third compared with Clearsonic tip (P < 0.05). Supplementary methods were effective in the reduction of root filling materials. XP‐endo Finisher R removed more root filling material than Clearsonic tip. [ABSTRACT FROM AUTHOR]

This study compared the efficacy of XP‐Endo Finisher R and R1‐Clearsonic insert in removing filling material remnants from oval canals. Twelve pairs of contralateral premolars were treated and subsequently retreated with Reciproc 50. A supplementary procedure with XP‐Endo Finisher R or R1‐Clearsonic was performed. Micro‐computed tomography was used to quantify the filling material volume in the full canal and apical segment lengths. Intragroup analyses revealed significant reduction of filling material after both procedures, not only in the full canal but also in the apical segment (P < 0.05). The amount of filling material removed with XP‐Endo Finisher R and R1‐Clearsonic was 47.9% and 52.2% in the apical segment (P > 0.05), and 82.1% and 64.6% in the full canal (P < 0.05). None of the instruments was effective in completely removing the filling material from the apical canal, but better results were obtained with XP‐Endo Finisher R in the total canal length. [ABSTRACT FROM AUTHOR]