Influencia de cimentos endodonticos na efetividade e extensão apical de tecnicas de desobturação dos canais radiculares estudo in vitro

Orientador: Luiz ValdrighiTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de PiracicabaResumo: O objetivo deste trabalho foi a avaliação in vitro da influência de três cimentos obturadores na eficácia de três técnicas de desobturação de canais sadiculares, bem como da extrusão de material obturador através do ápice radicular e do tempo despendido durante a aplicação destas técnicas. Empregaram-se 90 dentes unirradiculares humanos, extraídos, que foram divididos em três grupos de 30 unidades, os quais foram preparados e obturados com guta-percha e os cimentos obturadores a saber: Grupo I - Cimento Endomethasone; Grupo 11 - Cimento Sealer 26 e Grupo 111 ¿ Cimento Ketac-Endo. A seguir, cada um destes três grupos foi subdividido em três subgrupos de 10 dentes, de acordo com a técnica de desobturação empregada: Subgrupo A - Gates-Glidden + Limas + Solvente; Subgrupo B - Gates-Glidden + Ultra-som + Solvente e Subgrupo C - Gates-Glidden + Canal Finder + Solvente. Para cada grupo e subgrupo estudado, foram anotados o tempo efetivamente gasto na desobturação, a quantidade de material extruída através do ápice radicular e a quantidade de material obturador remanescente, permitindo concluir que o subgrupo A (Gates-Glidden + Limas + Solvente) foi o mais eficiente e mais rápido na desobturação independentemente do cimento obturador dos canais radiculares. O grupo de canais obturados com Ketac¬endo apresentou uma quantidade de material obturador remanescente maior que a dos grupos dos outros dois cimentos estudados. Observou-se ainda que a extrusão de material obturador foi estatisticamente não significativa e sem diferenças entre todos os grupos e subgrupos estudadosAbstract: The purpose of this study was to compare the efficiency of 3 techniques (A- Gates-Glidden I hand files; B- Canal Finder; C- Ultrasonic) on removing filling material from root canal system filled with 3 different sealers (Endomethazone, Sealer 26 and Ketac Endo) and also the amount of filling material missed through the root apex during the application of these techniques. Ninety human extracted one root teeth were prepared using a step back technique and obtllrated with laterally condensed gutta-percha connected to one of the 3 sealers mentioned (3 groups of 30 teeth filled with each sealer). Each group of 30 teeth was divided in 3 groups of 10 teeth, and one of the 3 techniques in conjunction with chloroform were used to remove the filling material. During the removing of filling material from root canal, the tooth was fixed in a plastic box that had a filter paper (that was weighted before) under the tooth apex, where the lost material was received, making possible to obtain the loss of filling material in each tooth. Afier the use of the techniques, the teeth were radiographed. The total area of the canal and the area of remaining material were traced and afier quantified using a computerized image analysis system. The ratio of remaining obturation material to root canal periphery was encountered and statistically analyzed (Tuckey's test). Results showed 29,11 % of remaining gutta-percha I sealer in "A" technique, 43,94% in "B" and 48,33% in "C". Teeth filled with Endomethazone showed 33,60% of remaining material, Sealer 26 showed 33,90% and Ket~c Endo 53,45%. In conclusion, the most effective technique was liA", the worst sealer to be removed from root canal system was Ketac Endo and the loss of filling material through the root apex was the same for ali the techniques and sealers tested.DoutoradoEndodontiaDoutor em Clínica Odontológic

Effects of Glide Path on the Centering Ability and Preparation Time of Two Reciprocating Instruments

Introduction: The aim of this in vitro study was to evaluate the effects of establishing glide path on the centering ability and preparation time of two single-file reciprocating systems in mesial root canals of mandibular molars. Methods and Materials: Sixty extracted mandibular molars with curvatures of 25-39 degrees and separate foramina for the mesiobuccal and mesiolingual canals, were divided into four groups (n=15); WaveOne+glide path; WaveOne; Reciproc+glide path and Reciproc. Non-patent canals were excluded and only one canal in each tooth was instrumented. A manual glide path was established in first and third groups with #10, 15 and 20 hand K-files. Preparation was performed with reciprocating in-and-out motion, with a 3-4 mm amplitude and slight apical pressure. Initial and final radiographs were taken to analyze the amount of dentin removed in the instrumented canals. The radiographs were superimposed with an image editing software and examined to assess discrepancies at 3-, 6- and 9-mm distances from the apex. The Kruskal-Wallis test was used for statistical analysis. The level of significance was set at 0.05. Results: Preparation in groups without glide paths was swifter than the other groups (P=0.001). However, no difference was observed regarding centering ability. Conclusion: Establishing a glide path increased the total instrumentation time for preparing curved canals with WaveOne and Reciproc instruments. Glide path had no influence on the centering ability of these systems.Keywords: Centering Ability; Glide Path; Reciproc; Root Canal Preparation; Single-File Instrumentation; WaveOn

Irrigant Agitation Techniques versus Passive Ultrasonic Irrigation for Removing Debris from Curved Root Canals: An Environmental Scanning Electron Microscopic Study

Introduction: The aim of this study was to compare the efficacy of passive ultrasonic irrigation (PUI) versus mechanical agitation of the irrigant promoted by the EasyClean (EC) and XP-Endo Finisher (XP-F) systems in removing debris from root canal walls, using environmental scanning electron microscopy (ESEM). Methods and Materials: Twelve curved mesiobuccal canals of mandibular molars were prepared with the ProTaper Next system up to file X2 (25/0.06). The specimens were embedded in flasks containing silicone putty, sectioned lengthwise, and a 4-mm long groove was made on the canal wall of the buccal half of the specimen, extending from 2 mm up to 6 mm short of the apex. Five cross-sectional markings were made along this groove to establish standardized locations for imaging. The same specimens were used to prepare a negative control group (without debris), a positive control group (completely covered by debris), and 3 experimental groups according to the final irrigation protocol employed: PUI, EC or XP-F. ESEM images were obtained and evaluated by 3 examiners. The amount of debris observed on the images was classified according to a 4-category scoring system. The kappa test was used to assess inter-examiner agreement, and the Kruskal-Wallis and Dunn tests were used to compare the scores (P<0.05). Results: The scores attributed to the PUI, EC, and XP-F groups were statistically similar to those attributed to the negative control group (P>0.05). Conclusion: Based on this in-vitro study, the mechanical agitation of the irrigant promoted by EC and XP-F was as effective as using PUI to remove debris from the root canal walls

Effectiveness of Sodium Hypochlorite plus EDTA Compared with Peracetic Acid in Removing Smear Layer and Killing Enterococcus faecalis

Introduction: The aim of this study was to evaluate the effectiveness of 2.5% sodium hypochlorite associated with 17% Ethylenediaminetetraacetic acid (NaOCl-EDTA), versus that of 1% peracetic acid (PA), in removing the smear layer, as assessed by scanning electron microscopy (SEM), and in exerting bactericidal action against Enterococcus faecalis (E. faecalis), as assessed by the real-time polymerase chain reaction (real-time PCR). Methods and Materials: Fifty-five extracted mandibular single-rooted premolars were selected, and divided into two experimental groups (NaOCl-EDTA and PA; n=25) and one control group (0.9% saline; n=5). Pre- and post-instrumentation samples were collected and assessed for the presence of E. faecalis using real-time PCR. The teeth were instrumented using hand files and the ProTaper Universal system (hybrid technique) for a standardized time of 7 min. A total of 20 mL of NaOCl followed by 5 mL of EDTA were applied during instrumentation in the NaOCl-EDTA group, whereas 20 mL of PA and 20 mL of saline were applied in the PA and control groups, respectively. An additional 5 mL of saline was applied in all the groups to neutralize the environment. A scoring system was used to conduct the SEM assessment. The results were submitted to the Kruskal-Wallis test, complemented by Dunn's test (SEM analysis) (P<0.05). Results: A significant microbial reduction was observed in both the PA and the NaOCl-EDTA groups (P<0.05). In the PA group, the presence of a smear layer in the apical third was significantly greater than in the cervical third (P<0.05); no significant differences were observed between the middle and cervical thirds, or between the middle and apical thirds (P>0.05). In the NaOCl-EDTA group, the smear layer scores were significantly higher in the apical third than in the cervical and middle thirds (P<0.05). Conclusion: This in vitro study showed that there was no significant difference between PA and NaOCl-EDTA irrigation regimens regarding either antimicrobial action against E. faecalis or removal of the smear layer, except for greater removal in the middle third by the NaOCl-EDTA group.Keywords: Endodontic Irrigation; Enterococcus faecalis; Peracetic Acid; Real-Time Polymerase Chain Reaction; Sodium Hypochlorite

Root Fracture Resistance of Maxillary Premolars Obturated with Three Root Canal Sealers after Passive Ultrasonic Irrigation: An in Vitro study

Introduction: Maxillary premolars, may be more susceptible to fracture due to their anatomy; especially when there is loss of tooth structure. Therefore, it is necessary to evaluate materials and techniques that may increase fracture resistance during and post root canal treatment. This in vitro study aimed to evaluate root fracture resistance of maxillary premolars when filled with three root canal sealers as well as whether this resistance would be increased by passive ultrasonic irrigation (PUI). Methods and Materials: Sixty-four maxillary premolars with two roots were randomly divided into one negative control group (intact canals; n=8), one positive control group (instrumented, unsealed canals; n=8), and six experimental groups (n=8), which were instrumented with ProTaper Next rotary system up to X2 file and subdivided according to final irrigation (with or without PUI) and type of sealer used (AH-Plus [AH], MTA Fillapex [MTA], or EndoSequence BC Sealer [ES]). The specimens were subjected to fracture strength test in a universal testing machine at a speed of 1 mm/min until fracture. The maximum force required to induce fracture was recorded (N).  Results: The lowest force required to cause root fracture was observed in the positive control group (310.48±54.08 N); this was significantly different from the other groups (P<0.05). There was no significant difference between experimental groups obturated with the same sealer, whether with or without PUI (AH with PUI: 558.80±87.12 N; AH without PUI: 508.75±97.55 N; MTA with PUI: 507.27±174.55 N; MTA without PUI: 516.69±96.56 N; ES with PUI: 526.76±143.97 N; ES without PUI: 628.40 ± 94.74 N) (P>0.05). There was also no significant difference between the experimental groups and the negative control group (P>0.05). Conclusions: In this in vitro study PUI did not increase the fracture resistance of maxillary premolars, while AH Plus, MTA Fillapex, EndoSequence sealers increased fracture resistance of instrumented root canals

Removal of Obturation Material from Root Canals Using a Combination of Reciprocal Instrumentation and Different Final Irrigation Techniques

Introduction: The predictability of successful non-surgical endodontic retreatment is directly related to it’s ability to completely cleanse and remove obturation material from the canal system. The purpose of this study was to evaluate the removal of gutta-percha from curved canals using three final irrigation methods: passive ultrasonic irrigation (PUI) with a 20/01 E1 insert (Irrisonic); XP-endo Finisher (XPF); and Easy Clean (EC). Methods and Materials: Forty mesial roots of mandibular molars with an angle of curvature between 10° and 20°, two canals, and independent foramina were cut into 16-mm sections. The canals were instrumented using the Reciproc system (R25) and filled with a #25 gutta-percha cone and AH-Plus sealer by the continuous-wave condensation technique. The roots were double-sealed with Coltosol and photopolymerizable resin and stored at 37°C and 100% humidity for 30 days. They were then randomized into 4 groups (n=10): control (C), PUI, XPF, and EC. All specimens were scanned using cone-beam computed tomography (CBCT), and fill volume data (in square pixels) were calculated before retreatment, after retreatment, and after final irrigation. The images were analyzed using Tps Dig software 2.32 by two blinded, calibrated examiners (intra-class correlation coefficient=0.9967). The results were analyzed in BioEstat 4.0. The nonparametric Kruskal-Wallis test with Dunn's post-hoc and Friedman comparison were applied. Significance was accepted at 5% (P<0.05). Results: None of the final irrigation protocols completely removed remnants of obturation material from the root canal systems (P>0.05). On comparative analysis with specimens divided into thirds, all methods were found to remove material equally, with no significant differences (P>0.05). Conclusion: Based on this in vitro study, the additional cleaning methods tested were equivalent to each other and did not lead to an improvement in the removal of residual obturation material

Factors Associated with Post-Endodontic Treatment Pain Performed by Students in an Endodontic Graduate Program

Introduction: The aim of this study was to evaluate the possible associations between pre-established clinical variables and manifestation of postoperative pain after endodontic treatments performed by graduate students in endodontics, from June 2016 to December 2017. Methods and Materials: A total of 998 dental patient charts were included in the study. All the patients underwent the same clinical protocol. Possible associations between postoperative pain and clinical variables were investigated, including age, gender, type of tooth, type of treatment, pulpal diagnosis, periradicular diagnosis, instrumentation system used, number of sessions, previous symptom, procedural accident, and endodontic sealer extrusion. Patients were contacted by telephone 24 h and 7 days after treatment completion and were asked about the degree of postoperative pain they had experienced, using a four-level scoring system: 0, no pain; 1, mild pain (no medication was needed); 2, moderate pain (an analgesic or anti-inflammatory was needed); 3, severe pain. Fischer’s exact test, Pearson’s test, and logistic regression were used for the statistical analysis of the data. A significance level of 0.05 was used. Results: A total of 8.6% of the patients reported having experienced postoperative pain, 50% of which reported mild pain, 47.7%, moderate pain, and 2.3%, severe pain. The only variable significantly associated with postoperative endodontic pain was pre-endodontic treatment symptoms (Pearson’s test, P=0.0047). The logistic regression analysis indicated that the association between use of the Reciproc system and sealer extrusion posed a significant risk for postoperative endodontic pain. Conclusion: Based on this retrospective cohort study, the incidence of moderate and severe pain after endodontic treatment was low, and the only variable associated with a higher frequency of patients reporting postoperative endodontic pain was previous pain/symptoms. Therefore, in these cases, pain management methods such as the use of analgesics before treatment or immediately after treatment should be considered

Comparison of the effectiveness of the protaper system versus hand instrumentation in endodontic retreatment: a scanning electron microscopy study

Abstract Introduction: Several rotary systems have been evaluated for removal of endodontic filling materials from the canal. Moreover, studies focusing on the comparison of the effectiveness of rotary systems versus hand instrumentation have yielded mixed results in terms of the efficacy and amount of time required by each technique. Objective: To compare the effectiveness of a nickel-titanium rotary system and of hand instrumentation using stainless steel files and Gates-Glidden burs in the removal of gutta-percha from root canals, as well as the time required to complete the procedure by each method. Material and methods: Forty single-rooted teeth were prepared and obturated then divided in two groups, according to the method employed for removal of the gutta-percha: ProTaper Universal rotary retreatment system (rotary instrumentation) and stainless steel hand files with Gates-Glidden burs (hand instrumentation). The time required to remove gutta-percha by each method was recorded. Roots were then sectioned lengthwise and the apical, middle, and coronal thirds were analyzed by SEM under two magnifications: x400 an

Scaffolding geospatial epistemic discomfort: a pedagogical framework for cross-disciplinary landscape research

Current environmental crises call for an integrated knowledge of landscapes and their ecosystems in a broader sense. This article presents a pedagogical framework for cross-disciplinary landscape research at postgraduate level. The framework is grounded in the use of geospatial epistemic discomfort as a creative force to develop and enhance inquiry skills able to cross and merge disciplinary boundaries. Developed within the Erasmus+ KA2 project "CROSSLAND", the pedagogical framework is based on the scaffolding of epistemic discomfort through four key didactic elements: 1) cross-disciplinary group work and open-ended assignment, 2) in-field inquiry as pre-training on space-time, 3) replacement of traditional lectures by student-led seminars, 4) GIS labs centred on the exploration of cross-disciplinary portfolios of geospatial approaches and methods given as worked-out examples. Main results from the evaluation of the framework implementation in a Summer School show how learning cross-disciplinarity happened thanks to a scaffolding that allowed, first and foremost, the socialisation of different conceptualisations of space. While students felt at ease with geospatial epistemic discomfort, we can conclude that spatial cognitive processes are powerful in improving abilities beyond the spatial domain

Regeneração de pitaya por organogênese indireta avaliada por microscopia eletrônica de varredura e citometria de fluxo

The objective of this work was to evaluate the induction of indirect organogenesis by concentrations of dichlorophenoxyacetic acid (2,4-D) and thidiazuron (TDZ) in pitaya (Hylocereus undatus) explants, using scanning electron microscopy and the flow cytometry technique. The treatments consisted of the concentrations of 0, 2.0, and 4.0 mg L-1 2,4-D and TDZ and of the combinations of these regulators. Percentages of callus coverage at 45 and 60 days were evaluated. The explants subjected to the treatments were analized by flow cytometry and scanning electron microscopy. All treatments induced endoreduplication, and there was no somaclonal variation. Under the combination of 2.0 mg L-1 TDZ and 4.0 mg L-1 2,4-D, calluses were formed in 95% of the explants, but were smaller than those produced with 2,4-D separately. The concentration of 2.0 mg L-1 TDZ induces the indirect organogenesis in pitaya explants, confirmed by the presence of conducting vessels through scanning electron microscopy.O objetivo deste trabalho foi avaliar a indução de organogênese indireta por concentrações de ácido diclorofenoxiacético (2,4-D) e tidiazurom (TDZ) em explantes de pitaia (Hylocereus undatus), por meio de microscopia eletrônica de varredura e da técnica de citometria de fluxo. Os tratamentos consistiram das concentrações de 0, 2,0 e 4,0 mg L-1 de 2,4-D e TDZ e das combinações desses reguladores. Avaliaram-se as percentagens de cobertura de calos aos 45 e 60 dias. Os explantes submetidos aos tratamentos foram analizados por citometria de fluxo e microscopia eletrônica de varredura. Todos os tratamentos induziram endorreduplicação, e não houve variação somaclonal. Na combinação de 2,0 mg L-1 TDZ e 4,0 mg L-1 2,4-D, calos foram formados em 95% dos explantes, mas foram menores do que os produzidos com 2,4-D separadamente. A concentração de 2,0 mg L-1 de TDZ induz organogênese indireta em explantes de pitaia, comprovada pela presença de vasos condutores por meio da microscopia eletrônica de varredura