Challenges in long-oval canal cleaning: effects of instrumentation kinematics and ultrasonic irrigation Sandra Soares Kühne Busquim, Laila Gonzales Freire, Iandara de Lima Scardini, Marcelo dos Santos Brazilian Dental Journal, 2025 The present study aimed to evaluate, using micro-CT imaging, the preparation of long-oval root canals performed by Twisted File Adaptive (TFA) and Reciproc (RC) instruments and the cleaning efficacy of final ultrasonic irrigation (UI) using a correlative scanning electron microscopic (SEM) approach. Distal long-oval canals of thirty-eight lower molars were divided into two groups (n=19): TFA and RC groups. Each specimen underwent three scans: pre- and post-instrumentation and post-UI, and changes in volume, non-prepared surfaces, and accumulated hard-tissue debris (AHTD) were measured. Then, root canals were halved at the apical third and analyzed under SEM for smear layer (SL) evaluation. Mann-Whitney and Kruskal-Wallis tests were used for statistical analysis (p<0.05), and the correlation between the AHTD and the SL was evaluated with Pearson's correlation coefficient. The TFA system exhibited greater efficiency in dentin removal compared to the RC system when considering the entire canal (p<0.05), with approximately 26 to 29% of surface area unprepared for the whole canal (p>0.05). Both systems produced the same volume of AHTD (p>0.05). Final UI led to a notable reduction in AHTD (60-70%), except in the apical third. Qualitatively, SEM analysis revealed non-uniform dentin remnants covering the canal walls, particularly prominent in the RC group. The data analysis determined a strong correlation between AHTD and SEM evaluation. In conclusion, neither system achieved complete preparation of long-oval root canal walls, and the final UI reduced AHTD. The AHTD observed by micro-CT was related to the presence of SL evaluated by SEM.
Using manual versus mechanized glide path instruments and ProTaper Gold versus ProTaper Next systems in curved canals: micro-CT study Breno Nappi VENTURA, Giulio GAVINI, Elaine Faga IGLECIAS, Laila Gonzales FREIRE, Celso Luiz CALDEIRA Brazilian Oral Research, 2024 The aim of this study was to evaluate the root canal shaping effect of ProTaper Gold (PTG) versus ProTaper Next (PTN) instrumentation systems, and of a manual #15 K-type file (K15) versus the ProGlider (PG) mechanized instrument for glide path creation, in severely curved mesial canals. Twenty-four mandibular molars with two separate mesial canals were anatomically matched using computed tomographic scanning, and then divided into two groups (n=12) according to the glide path instrument used, either K15 or PG. In all teeth, the PTG system was used to prepare the mesiobuccal canal, and the PTN, the mesiolingual canal. The teeth were scanned by computed microtomography, before and after root canal preparation, and the values of the initial volume, final volume, volumetric variation, untouched walls, and canal transportation variables were determined. The data were analyzed using the two-way ANOVA test, and the Tukey test for multiple comparisons. There was no significant difference among the study groups regarding volumetric variation or root canal transportation, either in the cervical, middle or apical thirds, or in the entire root canal (p>0.05). In the apical third, the percentage of untouched walls was significantly higher in groups using K15 than in those using PG (p<0.05), namely 33.144% and 23.285%, respectively, irrespective of the instrumentation system. In the other regions, there was no difference between K15 and PG regarding this variable. It was concluded that PG was associated with a lower rate of untouched walls in the apical region than K15.
Root canal curvature influences uncontrolled removal of dentin and cleaning efficacy after ultrasonic activation Hermano Camelo Paiva, Elaine Faga Iglecias, Laila Gonzales Freire, George Táccio de Miranda Candeiro, Basílio Rodrigues Vieira, et al. Brazilian Dental Journal, 2024 This study evaluated the correlation between root canal curvature and the effects of ultrasonic irrigation in the following parameters: volume of uncontrolled dentin removal (UDRVol), maximum depth of dentin defects, removal of accumulated hard tissue debris (AHTD), and canal transportation in prepared curved root canals. Twenty-four human permanent mandibular molars were divided into two groups according to root canal curvature: moderate curvature (MC: mean 25°); and severe curvature (SC: mean 48°). The specimens were scanned using an X-ray microcomputed scanner (Skyscan 1172) before and after cleaning and shaping and after the final irrigation protocol with ultrasonic irrigation. There was a moderate correlation between the degree of root canal curvature and the volume of remaining AHTD (p<0.05) and between the degree of root canal curvature and maximum depth of defects due to uncontrolled removal of dentin (p<0.05). The teeth in the SC group had a greater maximum depth of defects on the dentin wall in the apical third than the teeth in the MC group (p <0.05). Both groups had a significant reduction of AHTD in all canal thirds, but the amount of remaining AHTD in the middle and apical thirds and the whole canal was significantly greater in the SC than in the MC group (p <0.05). Canal transportation was not influenced by the canal curvature in all thirds (p >0.05). This study concluded that root canal curvature affects significantly the uncontrolled removal of dentin and remaining AHTD volume after the final irrigation protocol with ultrasonic irrigation.
The Effect of Number of Visits, Use of Solvent and Gutta-percha Removal Technique on Postoperative Pain following Nonsurgical Endodontic Retreatment; A Systematic Review and Meta-analysis Iandara de Lima Scardini, G. Sarra, M. Braga, Marcelo dos Santos, L. Freire Iranian Endodontic Journal, 2023 Introduction: The nonsurgical endodontic retreatment (NERT) is the first choice of dental ministration when primary/initial endodontic treatment fails. The present study aimed to investigate the presence of postoperative pain (POP) after NERT in permanent asymptomatic teeth as well as possible factors associated with POP. Materials and Methods: A comprehensive search of literature was performed in Pubmed/MEDLINE, Embase, Scopus and Web of Science databases, up to January 2023; including randomized clinical trials and prospective studies. The risk of bias was assessed with RoB 2.0 and ROBINS-I tools. Subgroups analyses were conducted to evaluate the differences in the incidence or level of POP between the number of visits, the use/not use of solvent, the removal technique of gutta-percha, and the period of POP analysis. Mean differences and confidence intervals (CI) of 95% were used as measures of effect, and meta‐regression was used along with subgroup analysis. The certainty of evidence was assessed using GRADE, and the probability value of <0.05 was considered significant. Results: Twenty-four studies were selected, with thirteen included in the meta-analysis. There was a statistical difference between the incidence of POP after 24 h (95% CI, 0.28 to 0.52) and one week (95% CI, 0.02 to 0.13) from the endodontic retreatment (P<0.01). However, there was no statistical difference between different techniques, number of visits and use of solvent (P>0.05) in the same period. In addition, the certainty of evidence was very low. Conclusions: Post-operative pain is a common response to NERT, independent of the retreatment technique(s) applied, number of visits and use of solvent(s); with very low certainty of evidence as well as low risk of bias. Moreover, the current analysis showed a (very) serious risk of inconsistency and imprecision. However, POP was significantly reduced within 1 week of the NERT.
Surface profile of different heat-treated nickel-titanium files before and after root canal preparation Iandara de Lima Scardini, Denise Maria Zezell, Juliana Lisboa Couto Marques, Laila Gonzales Freire, Marcelo dos Santos Brazilian Dental Journal, 2022 The aim of this study was to evaluate surface wear, presence of microcracks and surface irregularities of WaveOne (WO) and WaveOne Gold (WOG) instruments before and after multiple uses. Eight Primary instruments of the WO and WOG systems were evaluated, each one was used to prepare six mesial canals of extracted human mandibular molars. The surface of the instruments was evaluated before use (T0), after instrumentation of three (T1) and six (T2) root canals. Surface wear was analyzed using a three-dimensional optical profiler and the presence of microcracks and surface irregularities were evaluated using a tabletop scanning electron microscopy. The Friedman test was used to assess surface wear and Kruskal-Wallis test to evaluate the presence of microcracks and surface irregularities, with a 5% significance level. There was a significant increase in wear in both groups at T2, compared to T0 (p=0.0003). The surface wear after instrumentation of six canals (T2-T0) was statistically greater in the WOG group, than in the WO group (p=0.02), where the presence of microcracks was significantly greater and increased after multiple uses (p<0.05). The presence of surface irregularities in the cutting blade before and after use was statistically greater in the WOG group than WO group (p<0.05). Wear of the cutting blade, microcracks and surface irregularities were observed on the surface topography of all the instruments after multiple uses. These surface changes may affect the cutting efficiency of WOG files and increase the risk of fracture of WO files.
Shaping efficiency of XP-endo shaper and Mtwo instruments in long oval root canals: A micro-CT study Juliana Lisboa Couto Marques, Laila Gonzales Freire, Iandara de Lima Scardini, Basilio Rodrigues Vieira, Frederico Barbosa Sousa, et al. Australian Endodontic Journal, 2021 This study evaluated the shaping ability of XP-endo Shaper and Mtwo systems in long-oval-shaped canals of extracted human mandibular molars using micro-computed tomography (micro-CT). Images recorded before and after preparation were evaluated for morphometric measures regarding increase in canal volume, dentin removed, surface area, untouched walls and structure model index (SMI). Data were statistically analysed using the Mann-Whitney test with 5% of significance. On both groups, the root canal preparation significantly increased all analysed parameters (P > 0.05). There was no statistical difference between XP-endo Shaper and Mtwo systems in the increase of the canal volume (30.50%-27.82%), in volume of dentin removed (2.77%-2.40%), in the increase of the canal surface area (11.30%-8.86%), in canal untouched surfaces (9.57%-8.51%) and in the SMI (2.59%-2.68%), respectively. XP-endo Shaper and Mtwo systems showed similar shaping efficiency and were not able to completely prepare the walls of long-oval-shaped canals of extracted human mandibular molars.
Comparison of the success rates of four anesthetic solutions for inferior alveolar nerve block in patients with irreversible pulpitis. A prospective, randomized, double-blind study Dental Press Endodontics, 2011
