Retreatability of Bioceramic Endodontic Sealers: a Review.

In 2009 a new type of endodontic sealers was introduced to the market. The so called "bioceramic" sealers are a promising alternative to the present golden standard of root canal fillings. Now a decade later, still very little is known about the ability to remove these sealers in cases of non-surgical endodontic retreatment (NSER). There are only a limited number of articles that provide such information. The commonly used hand files are not efficient in removing thoroughly the sealer from the main canal walls. Machine driven files are much easier and faster alternative to the hand ones, but are still not able to ensure complete removal. Although ultrasonics can be applied only in the straight portion of the main canal, they raise the efficacy of sealer removal. Photon-initiated photoacoustic streaming (PIPS) is another way to enhance the removal of bioceramics. Solvents like chloroform and orange oil are effective in softening gutta-percha, but not the bioceramics. This article reviews the available scientific data concerning removal of bioceramic materials in the context of a NSER.

Secondary colonic stent insertion in acute large bowel obstruction following primary stent failure.

INTRODUCTION: Colonic stent insertion has been shown to be an effective treatment for patients with acute large bowel obstruction, either as a bridge to surgery or as definitive treatment. However, little is known of the role of secondary stent insertion following primary stent failure in patients considered inappropriate or high risk for emergency surgery. METHODS: Fourteen patients presenting with acute large bowel obstruction who had previously been treated with colonic stent insertion were studied. All underwent attempted placement of a secondary stent. RESULTS: Technical deployment of the stent was accomplished in 12 patients (86%) but only 9 (64%) achieved clinical decompression. Successful deployment and clinical decompression of a secondary stent was associated with older age (p=0.038). Sex, pathology, site of obstruction, duration of efficacy of initial stent and cause of primary failure were unrelated to outcome. No procedure related morbidity or mortality was noted following repeated intervention. CONCLUSIONS: Secondary colonic stent insertion appears an effective, safe treatment in the majority of patients presenting with acute large bowel obstruction following failure of a primary stent.

Treatment of Wide-Necked Bifurcation Aneurysms : Initial Results with the pCANvas Neck Bridging Device.

BACKGROUND: Recently, numerous devices dedicated to the treatment of wide-necked aneurysms have become available. We present our initial experience with the pCANvas device and present the technical success rate, clinical outcome and immediate angiographic occlusion rates. OBJECTIVE: We sought to determine the efficacy of flow with the pCANvas for the treatment of unruptured intracranial aneurysms. METHODS: We performed a retrospective review of our prospectively collected data to identify patients treated with the pCANvas device between February 2015 and February 2017. The patient demographics, aneurysm characteristics, immediate and delayed clinical and radiographic follow-up data were recorded. RESULTS: We identified 17 patients (13 female) treated only with the pCANvas device. The average age of the patients was 60.5 ± 13.3 years (range 25-75 years). The average dome width was 7.6 ± 3.2 mm (range 3-15.8 mm), dome height 7.1 ± 3.2 mm (range 3-12.9 mm) and neck width 5.4 ± 3.2 (range 3-16.3 mm). The average aspect ratio was 1.5 ± 0.8 (range 0.6-3.7). At the end of the procedure 15 aneurysms continued complete filling of the aneurysm (Raymond Roy Classification[RRC] 3) with 2 aneurysms showing only filling of the neck of the aneurysm (RRC 2). Early follow-up angiography was available for 16 patients and at this stage 11 aneurysms showed persistent and complete filling of the aneurysm (RRC 3), 5 aneurysms showed complete occlusion of the aneurysm (RRC 1) and 7 aneurysms underwent repeat treatment with coiling. CONCLUSION: The early results on the use of the pCANvas are promising; however, longer term follow-up and larger studies are required.

Comparison of the effectiveness of various rotary and reciprocating systems with different surface treatments to remove gutta-percha and an epoxy resin-based sealer from straight root canals.

AIM: To compare the Reciproc Blue, Reciproc and ProTaper Universal Retreatment systems with regard to the effective removal of epoxy resin-based sealer and gutta-percha during the retreatment of oval, straight root canals. METHODOLOGY: Forty-five extracted, human mandibular first premolars with single straight oval canals were selected on the basis of cone beam computed tomography evaluations. The root canals were instrumented with the ProTaper Next system up to the X2 file, and filled with gutta-percha and epoxy resin-based sealer using the cold lateral condensation technique. After 1 month, the samples were randomly divided into three groups (n = 15) according to the retreatment system used: Reciproc Blue R40, Reciproc R40 and ProTaper Universal. The specimens were scanned at the resolution of 1.2 µm by a microcomputed tomography device after the root filling and retreatment procedures, and the decrease in the volume of filling material after each retreatment protocol was measured. The results were analysed using the Kruskal-Wallis test and additional box-and-whisker plots. RESULTS: Although the volume of the filling material decreased significantly in all three groups (P < 0.05), none of the systems removed the material completely. The Reciproc system removed significantly more material than the ProTaper Universal (P < 0.001) and Reciproc Blue (P = 0.005) systems, with the latter two exhibiting equal volumes of remaining material (P = 0.068). CONCLUSION: The Reciproc system was more effective than the Reciproc Blue and ProTaper Universal Retreatment systems during the removal of filling material from oval, straight canals, although none of the systems completely removed the filling material.

Pipeline-assisted coiling versus pipeline in flow diversion treatment of intracranial aneurysms.

BACKGROUND AND PURPOSE: Flow-diversion therapy (FDT) for large and complex intracranial aneurysms is effective and considered superior to primary coil embolization. Data evaluating common treatment with both FDT and coiling continues to emerge, but information on outcomes remains scarce. This study aims to examine further the efficiency and outcomes correlated with joint FDT using pipeline embolization device (PED) and coiling compared to PED-alone in treating intracranial aneurysms. MATERIALS AND METHODS: Comparative review and analysis of aneurysm treatment with PED in 416 subjects were conducted. Joint modality, PED, and coiling were compared to PED-alone for aneurysm occlusion, recurrence, retreatment, thromboembolic or hemorrhagic events, and functional outcome using the modified Rankin Scale. Data on patient demographics, aneurysm characteristics, clinical and angiographic follow up, were also collected. Both univariate analysis and multivariate logistic regression modeling using mixed-effects were performed. RESULTS: Total of 437 aneurysms were treated using PED of which 74 were managed with both PED and coiling. Average patient-age was 56 years, the majority were men (85%), an average aneurysm size was 9 mm, and the majority were saccular aneurysms (84%). Larger aneurysm size was associated with a poor outcome in patients with unruptured aneurysms (OR = 1.06). Adjusted regression analyses revealed no differences between treatment groups in thromboembolic or hemorrhagic events, aneurysm occlusion rate, residual flow on follow up angiography, or functional outcome. CONCLUSIONS: Treatment of intracranial aneurysms with joint PED and coiling was safe with no increase in complications when compared to PED alone. Aneurysm occlusion rates and functional outcome with PED and coiling stays comparable to treatment with PED-alone.

Hemodialysis reinitiation using a resurrected mummy fistula: a case report.

BACKGROUND: Kidney allograft loss becomes an important cause of end-stage kidney disease and requires dialysis reinitiation. We report a case of a patient who restarted hemodialysis after his second kidney graft failure using a long-discarded autologous arteriovenous fistula. CASE PRESENTATION: A 62-year-old man was diagnosed with end-stage renal disease 20 year ago, and a native arteriovenous fistula was created for hemodialysis. After the patient received his first kidney transplantation, the hemodialysis fistula was discarded and chronically thrombosed for 13 years. When the patient experienced his second kidney graft loss and presented with uremia again, dialysis restart was needed. Under vascular ultrasound, but not x-ray, guidance, we successfully revascularized the patient's chronically occluded, long-discarded arteriovenous fistula access and used it for hemodialysis. The resurrected fistula remained patent and clinically useable for hemodialysis up to 18 months. CONCLUSIONS: This report provides the feasibility of ultrasound-guided transluminal angioplasty for the treatment of a mummy hemodialysis fistula, which could be considered when managing patients who need dialysis reinitiation.

Comparison between Single-file Rotary Systems: Part 1-Efficiency, Effectiveness, and Adverse Effects in Endodontic Retreatment.

INTRODUCTION: The aim of this study was to evaluate in vitro the performance of 3 single-file systems: WaveOne Gold Primary (WOG; Dentsply Sirona, Ballaigues, Switzerland), Hyflex EDM "one file" (EDM; Coltene/Whaledent, Alstatten, Switzerland), and XP Shaper (XP; FKG, La Chaux de Fonds, Switzerland), for nonsurgical endodontic retreatment on mandibular anterior teeth in regard to the amount of remaining filling material inside the canal, debris extrusion, and operation time. METHODS: Sixty extracted standardized mandibular incisors presenting with a single oval canal were prepared to size 30.04 and obturated using warm vertical condensation. After 30 days (37°C, 100% humidity), teeth were randomly divided into 3 groups (n = 20) according to the file used for retreatment (WOG, EDM, or XP operated at 3000 rpm). During the retreatment procedures, preweighed vials were used to collect apically extruded debris, and the time required to remove the filling material was recorded in seconds. Cone-beam computed tomographic scans were taken before and after the retreatment to determine the amount of remaining filling material inside the root canal space. Statistical analysis was performed using the Kruskal-Wallis test, 1-way analysis of variance, and the Pearson test at a 5% significance level. RESULTS: There was a statistically significant difference among the groups regarding the instrumentation time (P < .05). XP was the fastest to remove gutta-percha from the canals (40.54 ± 28.03 seconds) followed by EDM (55.77 ± 19.76 seconds) and WOG (105.92 ± 53.92 seconds). The percentage of remaining filling was significantly greater for WOG (26.65% ± 14.63%) (P < .05). No difference was found between EDM (13.51% ± 9.53%) and XP (8.60% ± 7.28%). No difference was found regarding the amount of extruded debris among the 3 groups (P > .05). CONCLUSIONS: XP was the most efficient in gutta-percha removal from the canals when operated at a higher speed (3000 rpm) followed by EDM and WOG.

Efficacy of Rotary and Hand Instrument in removing Gutta-percha and Sealer from Root Canals of Endodontically Treated Teeth.

AIM: One of the common dental procedures employed these days in patients with irreversible pulpitis is root canal therapy. In retreatment cases, it is necessary for complete removal of obturate gutta-percha (GP) from obturate root canal system. Various methods and techniques are available these days for this purpose. This study was aimed to assess the efficacy of D-RaCe files, ProTaper retreatment files, Mtwo retreatment files, and manual Hedstrom files (H-files) in removing filling materials from the root canals of the endodontically treated teeth. MATERIALS AND METHODS: The present study included comparative evaluation of efficacy of nickel-titanium (NiTi) retreatment instruments and H-files in removing GP and sealer from root canals. All the samples were randomly and broadly divided into four study groups based on the instrumentation technique for removing the root canal fillings. Evaluation of the results was done based on operating time and remaining root canal filling material. Stereomicroscopic evaluation of the samples was done at 8* magnification. RESULTS: All the results were assessed and analyzed by Statistical Package for the Social Sciences (SPSS) software. Least quantity of filling material was left by ProTaper retreatment files. When put together in decreasing order, the efficacy of different study groups, in terms of mean time taken for retreatment, was found to be as follows: D-RaCe > ProTaper Retreatment > Mtwo Retreatment > H-file. CONCLUSION: No single technique can completely remove obturating fillings from the root canals of endodontically treated teeth. However, rotary instruments are better in comparison with hand instruments for removing the GP from obturate root canals. CLINICAL SIGNIFICANCE: ProTaper retreatment files and D-RaCe files are recommended over other instrument systems in terms of quality for managing retreatment root canal cases.

Life-threatening DBS withdrawal syndrome in Parkinson's disease can be treated with early reimplantation.

INTRODUCTION: The deep brain stimulation (DBS) withdrawal syndrome (DBS-WDS) is a rare, life-threatening complication in Parkinson's disease (PD) patients with long disease duration and stimulation when stimulation is terminated for extended periods mostly due to infection of the DBS-hardware. METHODS, RESULTS: In five patients explantation became necessary because of infection after a mean of 11.4 years (range 4-15 years) of DBS and a mean disease duration of 24.6 years (range 3-22 years). Mean UPDRS motor-score pre-explantation was 38 points (range 24-55 points) which increased to a mean of 78.4 points (range 58-90 points) after explantation, despite optimal Levodopa dosing. Reimplantation of the hardware after 23 days (range 3-45 days) under antibiotic treatment led to an improvement to a mean of 40 points (range 25-73 points) and a complication free survival. CONCLUSION: Early reimplantation of the DBS-hardware is a treatment option of the DBS-WDS when the life-threatening urgency overrides surgical standards. Observation of the syndrome indicates pharmacological unresponsiveness of the dopaminergic system in advanced PD and long-term DBS.

Impact of the global outflow angle on recanalization after endovascular treatment of middle cerebral artery bifurcation aneurysms.

BACKGROUND AND PURPOSE: Intracranial aneurysm recanalization after endovascular treatment (EVT) remains a major problem. The goal of this study was to find new predictive factors of recanalization after EVT of middle cerebral artery (MCA) bifurcation aneurysms. METHODS: 96 MCA bifurcationaneurysms, ruptured or unruptured, treated by EVT between Septembre 2009 and December 2014, were retrospectively included. Clinical parameters and aneurysm characteristics were recorded. From the initial three-dimensional DSA, spatial coordinates found on parent and daughter arteries of MCA bifurcations gave four different flow angle values; inflow, outflows 1 and 2, and the global outflow angle (the sum of the two outflow angles). Inter- and intra-observer reproducibilities of three-dimensional angle value measurements were performed. RESULTS: Recanalization occurred in 25 cases (26%) and retreatment was performed in 11 cases (11%). Only 1 patient (1%) had rebleeding. Univariate analysis established the following as predictive factors of recanalization: high blood pressure (P=0.014), aneurysm height (P<0.001), aneurysm width (P<0.001), neck size (P<0.001), postoperative occlusion class (P=0.040), percentage of packing volume (P<0.001), as well as the two outflow angles (P=0.006 and 0.045), and the global outflow angle (P<0.001). Multivariate analysis revealed two independent risk factors for recanalization: the global outflow angle (OR=1.05; 95% CI 1.02 to 1.08; P<0.002) and aneurysm width (OR=0.67; 95% CI 0.46 to 0.96; P=0.031). A global outflow angle threshold <192° was found to be a risk factor for recanalization (OR=13.75; 95% CI 4.46 to 42.44), with a sensitivity of 80% and specificity of 77%. CONCLUSIONS: This study emphasizes that a new parameter, the global outflow angle, can be predictive of recanalization for MCA bifurcation aneurysms treated by EVT.

ÖGRO survey on radiotherapy capacity in Austria : Status quo and estimation of future demands.

BACKGROUND: A comprehensive evaluation of the current national and regional radiotherapy capacity in Austria with an estimation of demands for 2020 and 2030 was performed by the Austrian Society for Radiation Oncology, Radiobiology and Medical Radiophysics (ÖGRO). MATERIALS AND METHODS: All Austrian centers provided data on the number of megavoltage (MV) units, treatment series, fractions, percentage of retreatments and complex treatment techniques as well as the daily operating hours for the year 2014. In addition, waiting times until the beginning of radiotherapy were prospectively recorded over the first quarter of 2015. National and international epidemiological prediction data were used to estimate future demands. RESULTS: For a population of 8.51 million, 43 MV units were at disposal. In 14 radiooncological centers, a total of 19,940 series with a mean number of 464 patients per MV unit/year and a mean fraction number of 20 (range 16-24) per case were recorded. The average re-irradiation ratio was 14%. The survey on waiting times until start of treatment showed provision shortages in 40% of centers with a mean waiting time of 13.6 days (range 0.5-29.3 days) and a mean maximum waiting time of 98.2 days. Of all centers, 21% had no or only a limited ability to deliver complex treatment techniques. Predictions for 2020 and 2030 indicate an increased need in the overall number of MV units to a total of 63 and 71, respectively. CONCLUSION: This ÖGRO survey revealed major regional differences in radiooncological capacity. Considering epidemiological developments, an aggravation of the situation can be expected shortly. This analysis serves as a basis for improved public regional health care planning.

Meta-analysis of treatment outcomes of posterior circulation non-saccular aneurysms by flow diverters.

INTRODUCTION: Non-saccular aneurysms of the posterior circulation are uncommon but highly dangerous lesions. Flow diverter stents have been demonstrated to be effective treatments of various anterior circulation aneurysms, particularly large and giant proximal internal carotid artery aneurysms. However, evidence regarding the treatment of non-saccular posterior circulation aneurysms with flow diverters is lacking. METHODS: A systematic literature review of the English language literature since 2007 was conducted using PubMed, MEDLINE, and Embase. Keywords and MeSH terms included flow diversion, flow diverter, pipeline, surpass, intracranial aneurysm, vertebrobasilar, and non-saccular. Case reports were excluded. Angiographic and clinical outcomes were pooled using a random effects meta-analysis. RESULTS: 13 retrospective non-comparative studies reporting 129 patients and 131 aneurysm treatments were included. The average number of flow diverters per aneurysm was 4.33. Immediate complete or near complete occlusion of the aneurysm occurred in 25% (95% CI 1% to 60%), and long term occlusion in 52% (29-76%). Periprocedural stroke occurred in 23% of cases. Good long term neurologic outcome (modified Rankin Scale score ≤2) was achieved in 51% (95% CI 31% to 71%). Overall mortality was 21% (95% CI 7% to 38%) and morbidity was 26% (12%-42%). Retreatment was required in 5% (95% CI 0% to 14%). Good neurologic outcome rate was higher in vertebral artery aneurysms (83%) than other locations (18-33%). CONCLUSIONS: Flow diversion is a feasible and efficacious treatment for non-saccular aneurysms in the posterior circulation. However, the intervention carries a significant risk of periprocedural stroke, and is still associated with high overall mortality. Further studies are needed to identify significant treatment risk factors and optimize patient selection.

Comparison of two methods of irrigant agitation in the removal of residual filling material in retreatment.

The aim of this study was to compare the efficacy of passive ultrasonic irrigation and EasyClean for removing residual filling material in retreatment. Twenty-two maxillary lateral incisors with apical curvature were instrumented with ProTaper files and filled with Endofill using the lateral compactation technique. Removal of filling material was performed with Reciproc, Mtwo and ProDesign Logic 50/.01 files. The teeth were inserted in a silicone mould, which was placed in a metal muffle, and split to visualize the residual filling material. The samples were divided into two groups (n = 11) according to the irrigation protocol: Passive ultrasonic irrigation (PUI group) with 3 activations of 20 seconds and EasyClean (Easy Equipamentos Odontológicos, Belo Horizonte, Brazil) (EC group) used in continuous rotation with 3 activations of 20 seconds, both using NaOCl and EDTA. Environmental scanning electron microscopic images of the apical, middle, and cervical thirds were taken before and after the irrigant activation. The Kappa test was used to determine interexaminer agreement. Statistical analysis was performed using Kruskal-Wallis, Mann-Whitney, and Wilcoxon tests (p < 0.05). PUI and EC improved the removal of remnant filling material in all root canal thirds (p < 0.05). PUI and EC presented similar performance in the final step of retreatment (p > 0.05). No significant difference was observed in the removal of filling material in the apical, middle, and cervical thirds in both groups (p > 0.05). EasyClean in continuous rotary motion is useful in retreatment and was shown to be as effective as ultrasonic activation in the removal of remnant filling material.

A opção pelo retratamento não cirúrgico na presença de pinos intrarradiculares: riscos e benefícios / The option for nonsurgical retreatment in the presence of intraradicular posts: risks and benefits

Introdução: O retratamento não cirúrgico é uma opção de tratamento quando ocorre o insucesso no tratamento endodôntico, porém, em muitos casos, há necessidade da remoção prévia de pinos intrarradiculares. Objetivo: Esta revisão de literatura tem como objetivo citar os riscos e os benefícios da opção pelo retratamento endodôntico não cirúrgico na presença de pinos intrarradiculares, bem como citar materiais e técnicas para a remoção de diferentes tipos de pinos. Conclusão: A opção pelo retratamento endodôntico não cirúrgico, em casos em que há necessidade de remoção de pinos, é segura e de índice de sucesso considerável, por isso, deve-se levar em conta o conhecimento de técnicas e os fatores que podem influenciar durante o processo, a fim de prevenir acidentes, bem como saber que apenas a presença do pino intrarradicular não é indicação para o tratamento cirúrgico.

Introduction: Nonsurgical retreatment is a treatment option when the failure happens in the endodontic treatment, but in many cases, there is need for prior removal intrarradicular posts. Objectives: This literature review aims to cite the risks and benefits of option for nonsurgical endodontic retreatment in the presence of intraradicular posts and cite materials and techniques for removing different types of posts. Conclusion: The option for nonsurgical endodontic retreatment in cases where removal the posts there need, is safe and considerable success rate, therefore, one should take into account the knowledge of techniques and factors that may influence during the process, in order to prevent accidents, as well as to know that only the presence of intraradicular post is no indication for surgical treatment.

Use of biological mesh in trans-anal treatment for recurrent recto-urethral fistula.

PURPOSE: To report the author's experience on a mini-invasive technique using bioprosthetic plug and a rectal wall flap advancement in the treatment of recurrent recto-urethral fistula. MATERIALS AND METHODS: Between 2013 and 2015, seven patients with recurrent recto-urethral fistula were referred to the Pederzoli Hospital, Peschiera del Garda, Verona, Italy. Intraoperatively all patients were found to have a rectal wall lesion and were treated with urinary and fecal diversion. For the persistence of the fistula, all the patients underwent a mini-invasive treatment consisting on placement of a bioprosthetic plug in the fistula covered by an endorectal advancement flap through a trans-anal and trans-urethral combined technique. RESULTS: Median operative time was 48 min with a median blood loss of 30 ml. Median hospital stay was 3 days (IQR 1-3). No case of fistula recurrence or plug migration was described. None of the patients experienced fecal or urinary incontinence. All patients obtained complete fistula healing. CONCLUSIONS: Recurrent recto-urethral fistula is a challenging postsurgical complication for surgeons and urologists, and its best treatment is still unknown. Our method seems to be feasible and effective for the treatment of complex recto-urethral fistula.

The Efficacy of the WaveOne Reciprocating File System versus the ProTaper Retreatment System in Endodontic Retreatment of Two Different Obturating Techniques.

INTRODUCTION: This ex vivo study aimed to evaluate the efficacy of retreating GuttaCore (Dentsply Tulsa Dental Specialties, Tulsa, OK) and warm vertically condensed gutta-percha in moderately curved canals with 2 different systems: ProTaper Universal Retreatment (Dentsply Tulsa Dental) and WaveOne (Dentsply Tulsa Dental). METHODS: Eighty mesial roots of mandibular molars were used in this study. The mesiobuccal canals in each sample were prepared to length with the WaveOne Primary file (Dentsply Tulsa Dental). The canals were obturated with either a warm vertical approach or with GuttaCore and divided into 4 retreatment groups with the same mean root curvature: warm vertical retreated with ProTaper, warm vertical retreated with WaveOne, GuttaCore retreated with ProTaper, and GuttaCore retreated with WaveOne. The warm vertical groups were obturated using a continuous-wave technique of gutta-percha compaction, and the GuttaCore groups were obturated according to the manufacturer's instructions. After allowing sealer to set, each specimen was retreated with either the ProTaper Universal Retreatment files D1, D2, or D3 or with the WaveOne Primary file to the predetermined working length. The time taken to reach the working length was recorded. Instrument fatigue and failure were also evaluated. RESULTS: The post hoc 2-sample t tests showed that the overall mean total time taken to reach the working length for the warm vertical groups was significantly greater than that observed for the GuttaCore groups (mean = 87.11 vs 60.16 seconds, respectively), and the overall mean total time taken to reach the working length for WaveOne was significantly greater than that observed for ProTaper (99.09 vs 48.18 seconds, respectively). Two-way analysis of variance showed a significant main effect for both the type of experiment groups (F1,76 = 15.32, P = .0002) and the type of retreatments (F1,76 = 54.67, P < .0001). Also, the WaveOne Primary file underwent more separations than the ProTaper files. CONCLUSIONS: The WaveOne Primary file underwent more separations and was unable to remove gutta-percha as efficiently as the ProTaper Universal Retreatment files. Also, canals obturated with GuttaCore were retreated more efficiently and with fewer file separations than the canals obturated using continuous wave of warm gutta-percha.

Influence of solvents on the bond strength of resin sealer to intraradicular dentin after retreatment.

This study evaluated the removal of filling material with ProTaper Universal Rotary Retreatment system (PTR) combined with solvents and the influence of solvents on the bond strength (PBS) of sealer to intraradicular dentin after canal reobturation. Roots were endodontically treated and distributed to five groups (n = 12). The control group was not retreated. In the four experimental groups, canals were retreated with PTR alone or in combination with xylol, orange oil, and eucalyptol. After filling material removal, two specimens of each group were analysed by SEM and µCT to verify the presence of filling remnants on root canal walls. The other roots were reobturated and sectioned in 1-mm-thick dentin slices that were subjected to the push-out test. Data were analysed by two-way ANOVA and Tukey's test (α = 0.05). SEM and µCT analysis revealed that all retreatment techniques left filling remnants on canal walls. The control group (3.47 ± 1.21) presented significantly higher (p < 0.05) PBS than the experimental groups. The groups retreated with PTR alone (2.59 ± 0.99) or combined with xylol (2.54 ± 0.77) and orange oil (2.32 ± 0.93) presented similar bond strength (p > 0.05), and differed significantly from the group with eucalyptol (1.89 ± 0.63). The solvents reduced the PBS of the sealer to dentin and no retreatment technique promoted complete removal of filling material.

Influence of solvents on the bond strength of resin sealer to intraradicular dentin after retreatment

Abstract This study evaluated the removal of filling material with ProTaper Universal Rotary Retreatment system (PTR) combined with solvents and the influence of solvents on the bond strength (PBS) of sealer to intraradicular dentin after canal reobturation. Roots were endodontically treated and distributed to five groups (n = 12). The control group was not retreated. In the four experimental groups, canals were retreated with PTR alone or in combination with xylol, orange oil, and eucalyptol. After filling material removal, two specimens of each group were analysed by SEM and µCT to verify the presence of filling remnants on root canal walls. The other roots were reobturated and sectioned in 1-mm-thick dentin slices that were subjected to the push-out test. Data were analysed by two-way ANOVA and Tukey’s test (α = 0.05). SEM and µCT analysis revealed that all retreatment techniques left filling remnants on canal walls. The control group (3.47 ± 1.21) presented significantly higher (p < 0.05) PBS than the experimental groups. The groups retreated with PTR alone (2.59 ± 0.99) or combined with xylol (2.54 ± 0.77) and orange oil (2.32 ± 0.93) presented similar bond strength (p > 0.05), and differed significantly from the group with eucalyptol (1.89 ± 0.63). The solvents reduced the PBS of the sealer to dentin and no retreatment technique promoted complete removal of filling material.

Assessment of rotary and reciprocating movements in root canal filling material removal / Análise dos sistemas rotatórios e reciprocante com diferentes ligas na desobturação em retratamento endodônticos

The aim of this study was to evaluate the effects of preparation, filling removal material, reinstrumentation and reobturation of root canals with different Ni-Ti alloys in endodontic retreatment. Firstly, the selection and pairing of mesial root canals of mandibular molars (n = 45) were performed by computerized micro-tomography (micro-CT). After pairing, the specimens were divided into three groups (n = 15), instrumented with the Mtwo® (up to file 25.06), ProDesign Logic (25.06) and ProDesign R (25.06) systems. After this, the specimens were scanned again for root canal deviation analysis at 2, 4, 6, 8 and 10 mm from the apex and the volume increase of these root canals was evaluated through CTan Then, the root canals were filled with Endofill® with 0.1% rhodamine B and scanned in micro-CT once again. For the retreatment of the specimens, 3 groups were established according to the system used (Reciproc®, Hyflex® and ProDesign Duo Hybrid®). During the retreatment, the specimens were scanned in micro-CT in two more phases, after removal of filling material and after reinstrumentation of the root canals. All the images obtained previous and post-retreatment were compared to evaluate the capacity of removal filling material of each system through the volume of material remaining at 3mm in the apical third. Possible deviation of the root canal was assessed at 2, 4, 6, 8 and 10 mm from the apex. In addition, the times of preparation, removal filling material and reinstrumentation of these files were also evaluated. After the removal filling material and reinstrumentation of the root canals, they were refilled with AH Plus with 0.1% fluorescein. The specimens were sectioned crosswise into 2 mm slices to be analyzed by a confocal laser scanning microscope (CLSM) at 1, 3 and 5 mm from the apex, where the volume of material was evaluated through LAS X 3D and 2D software. The time of preparation, removal filling material and reinstrumentation of the root canals between the different systems was measured by a digital timer. The evaluation of canal volumetric increase and preparation time between Mtwo and ProDesign Logic systems were conducted using Student t-test analysis. Non-parametric Wilcoxon test was used to the intragroup comparison at the 2, 4, 6, 8 and 10 mm levels and non-parametric Mann-Whitney test was used to the comparison between groups in the root canal transportation in all sections of the root canal. The intra-group comparison regarding the presence or absence of root canal deviation after removal of root canal filling material and re-instrumentation was submitted to the parametric T-paired statistical test, since it had a normal distribution. The working time with the different alloys used to removal filling material an reinstrumentation was analyzed through parametric ANOVA e Tukey statistical test. The analysis of the remaining material present in the root canals was performed with nonparametric Kruskal-Wallis and Dunn tests. For the intra-group comparison between the different slices (1, 3 and 5 mm), the data were submitted to nonparametric Friedman and Dunn tests. The level of significance was established at 5% in all analysis. After the initial preparation of the root canals, the ProDesign Logic system proved to be faster than Mtwo system, with statistical difference between them (P <0.05). There was no statistical difference in root canal deviation after initial preparation and after retreatment (P> 0.05). In addition, the groups did not present a significant statistical difference to the volume increase of the root canals after the initial preparation or to the volume of filling material remaining after the retreatment (P> 0.05). The Reciproc system proved to be the fastest system for the removal filling material and reinstrumentation of the root canals (P <0.05). The present study demonstrated that the Prodesign Logic and Mtwo systems presented similar capacity of preparation of mesial root canals. The Reciproc, Hyflex and ProDesign Duo Hybrid systems are similar in the removal of filling material, preserving the original root canal shape in endodontic retreatment. However, Reciproc was the fastest compared to the other groups.(AU)

O presente trabalho teve como objetivo avaliar os efeitos decorrentes do preparo inicial, desobturação, reinstrumentação e reobturação de canais radiculares com diferentes ligas de Ni-Ti em casos de retratamento endodôntico. Primeiramente, foi realizado a seleção e o pareamento da anatomia de canais mesiais de primeiros molares inferiores (n=45) através de micro-tomografia computadorizada (micro-CT). Após o pareamento dos espécimes, os mesmos foram divididos em três grupos (n =15), instrumentados com os sistemas Mtwo® (até a lima 25.06), ProDesign Logic (25.06) e ProDesign R (25.06) sendo escaneados novamente para análise de desvio do canal radicular a 2, 4, 6, 8 e 10 mm, além do aumento de volume desses canais, avaliados através do CTan. Em seguida, os canais radiculares foram obturados com o cimento Endofill® acrescido de 0,1% de rodamina B e escaneados em micro-CT mais uma vez. Para o retratamento dos espécimes, foram estabelecidos 3 grupos, de acordo com o sistema utilizado (Reciproc®, Hyflex® e ProDesign Duo Híbrido®). Durante o retratamento, os espécimes foram escaneados em micro-CT em mais duas etapas, após a desobturação e a após a reinstrumentação dos canais. Todas as imagens obtidas referentes ao pré e pós retratamento foram confrontadas com o intuito de avaliar a capacidade de remoção de material obturador de cada sistema através do volume de material remanescente nos 3 mm apicais, além de avaliar possíveis desvios dos canais a 2, 4, 6, 8 e 10 mm do ápice. Foram avaliados também, o tempo efetivo de preparo, desobturação e de reinstrumentação desses instrumentos. Após a desobturação e reinstrumentação dos canais, os mesmos foram reobturados com cimento AH Plus acrescido de 0,1% de fluoresceína. Os espécimes foram seccionados transversalmente em fatias de 2 mm para serem analisados em microscópio confocal de varredura a laser (MCVL) a 1, 3 e 5 mm do ápice, onde foi avaliado, através do software LAS X 3D e 2D, o volume de material obturador antigo. O tempo de preparo, desobturação e reinstrumentação dos canais entre os diferentes sistemas foi marcado através de um cronômetro digital. A análise do aumento volumétrico e tempo de preparo entre os sistemas Mtwo e ProDesign Logic foi feita através do teste estatístico Student t. Para a análise do desvio do canal radicular após o preparo inicial, o teste não-paramétrico Wilcoxon foi utilizado para a comparação intra-grupos nos níveis a 2, 4, 6, 8 e 10 mm do ápice, enquanto o teste não-paramétrico Mann-Whitney foi utilizado para comparação entre os grupos nos mesmos níveis. Para a análise do desvio do canal radicular após a desobturação e reinstrumentação dos canais, os dados foram submetidos ao teste paramétrico T-pareado. O tempo de desobturação e reinstrumentação com os diferentes sistemas foi analisado através do teste ANOVA e Tukey. Os dados referentes ao remanescente de material obturador foram analisados através dos testes não-paramétrico Kruskal-Wallis e Dunn. Para a comparação intra-grupos entre os diferentes níveis (1, 3 e 5 mm) foram utilizados os testes não-paramétricos Friedman e Dunn. O nível de significância foi estabelecido a 5% em todas as análises. Após o preparo inicial dos canais, o sistema ProDesign Logic demonstrou ser mais rápido que o sistema Mtwo, havendo diferença estatística entre eles (P < 0.05). Não houve diferença estatística quanto ao desvio do canal radicular tanto após o preparo inicial quanto após o retratamento (P > 0.05). Além disso, os grupos também não apresentaram diferença estatística significante quanto ao aumento do volume dos canais após o preparo inicial, nem em relação ao volume de remanescente de material obturador após o retratamento (P > 0.05). O sistema Reciproc demonstrou ser o mais rápido dentre os sistemas quanto à desobturação e reinstrumentação dos canais (P < 0.05). O presente trabalho demonstrou que os sistemas Prodesign Logic and Mtwo apresentaram capacidade similar de preparo dos canais mesiais de molares inferiores. Os sistemas Reciproc, Hyflex e ProDesign Duo Híbrido são parecidos quanto à remoção de material obturador, preservando o formato original do canal em casos de retratamentos entodônticos. Entretanto, Reciproc foi o mais rápido comparado aos outros grupos.(AU)