In silico toxicity and immunological interactions of components of calcium silicate-based and epoxy resin-based endodontic sealers.

OBJECTIVES: The present study aimed to determine in silico toxicity predictions of test compounds from hydraulic calcium silicate-based sealers (HCSBS) and AH Plus and computationally simulate the interaction between these substances and mediators of periapical inflammation via molecular docking. MATERIALS AND METHODS: All chemical information of the test compounds was obtained from the PubChem site. Predictions for bioavailability and toxicity analyses were determined by the Molinspiration Cheminformatics, pkCSM, ProTox-II and OSIRIS Property Explorer platforms. Molecular docking was performed using the Autodock4 AMDock v.1.5.2 program to analyse interactions between proteins (IL-1ß, IL-6, IL-8, IL-10 and TNF-α) and ligands (calcium silicate hydrate, zirconium oxide, bisphenol-A epoxy resin, dibenzylamine, iron oxide and calcium tungstate) to establish the affinity and bonding mode between systems. RESULTS: Bisphenol-A epoxy resin had the lowest maximum dose tolerated in humans and was the test compound with the largest number of toxicological properties (hepatotoxicity, carcinogenicity and irritant). All systems had favourable molecular docking. However, the ligands bisphenol-A epoxy resin and dibenzylamine had the greatest affinity with the cytokines tested. CONCLUSION: In silico predictions and molecular docking pointed the higher toxicity and greater interaction with mediators of periapical inflammation of the main test compounds from AH Plus compared to those from HCSBS. CLINICAL RELEVANCE: This is the first in silico study involving endodontic materials and may serve as the basis for further research that can generate more data, producing knowledge on the interference of each chemical compound in the composition of different root canal sealers.

Oxidative damage analysis and cell viability of Drosophila melanogaster exposed to three different endodontic sealers: an in vivo and ex vivo study.

The aim of this work was to evaluate the toxicological action of AH Plus (AHP), Bio-C Sealer (BCS), and EndoSequence BC Sealer (ESB), using Drosophila melanogaster as the model organism performing in vivo and ex vivo analysis. D. melanogaster were exposed for 10 days to three concentrations (5 mg/ml, 10 mg/ml, and 20 mg/ml) of AHP, BCS, and ESB sealers mixed with 10 ml of standard diet. During this period, the mortality of flies was evaluated. On the 11th day, the locomotor activity test was performed and the flies were euthanized for oxidative damage analysis (reactive species and lipid peroxidation) and cell viability (resazurin reduction). For the mortality curves evaluation, the log-rank test (Mantel-Cox) was used. For the analysis of other data, a one-way analysis of variance (ANOVA) was applied, followed by Tukey's post hoc test (α = 0.05). Regarding mortality, there were no significant differences. The locomotor activity was reduced, mainly in the two highest concentrations of AHP and BCS. Besides, reactive species generation was bigger in the AHP 20 mg/ml group. AHP induced a lipid peroxidation increase in all three concentrations tested, when compared to other sealers. Considering cell viability, the two highest concentrations of AHP reduced this parameter; while in other sealers, viability was reduced only in the highest concentration. AHP showed changes in oxidative markers that led to greater damage to the flies.

Apical periodontitis and associated factors in a rural population of southern Brazil: a multilevel analysis.

OBJECTIVES: This study aims to evaluate the association between apical periodontitis (AP) and sociodemographic/clinical factors in a probability sample of individuals living in a rural area of southern Brazilian. MATERIALS AND METHODS: A cross-sectional study was conducted involving 584 non-edentulous adult individuals who had undergone a full-mouth radiographic survey. Periapical status was analysed using the periapical index (PAI). Endodontic status was evaluated considering the occurrence of voids in the filling material and the root filling length. Crown status was classified based on the presence of caries, restorations, and prosthetic crowns. Sociodemographic variables, frequency of dental care, and periodontal disease were also registered. The data were analysed using hierarchical multilevel Poisson regression analysis. The multilevel structure was composed of three models: sociodemographic variables, clinical variables, and clinical variables adjusted by sociodemographic variables (α = 5%). RESULTS: The prevalence of AP in the sample was 60.45%. AP was significantly associated with age, skin colour, schooling, periodontal disease, and frequency of dental care (P < 0.005). Among the 10,396 teeth evaluated, 868 (8.35%) had AP, which was significantly associated with tooth group, dental arch, crown status, and endodontic treatment (P < 0.005). CONCLUSIONS: The prevalence of AP was high in the population studied. An older age, black/brown skin colour, low level of schooling, infrequent dental care, severe periodontal disease, mandibular teeth, posterior teeth, inadequate crown status, and having undergone endodontic treatment were significantly associated with the outcome. Clinical relevance This study about a rural probability sample reinforces that AP is still a recurrent oral health problem.

Tooth discoloration caused by endodontic treatment: A cross-sectional study.

INTRODUCTION: This cross-sectional study evaluated the influence of endodontic filling material, cervical limit of root filling, and tooth location on the color variation (∆E00 ) from 1 to 60 months of follow-up. MATERIALS AND METHODS: Color records were obtained from 70 participants who received 83 endodontic treatments. CIEL*a*b* color coordinates were measured on the homologous tooth, which was considered as baseline, and on endodontic treated teeth with a spectrophotometer. ∆E00 was calculated by the CIEDE2000 method at three conditions (condition 1: homologous tooth vs endodontically treated tooth after ≤1 month; condition 2: homologous tooth vs endodontically treated tooth after >1-12 months; condition 3: homologous tooth vs endodontically treated tooth after >12 months up to 5 years) for each variable. The zinc oxide and eugenol mineral trioxide aggregate or resin-based filling materials, dental cervix or ≥2 mm in the apical direction cervical limit of root filling and anterior or posterior tooth location were considered in the comparisons. Confidence intervals for the means (95% CI) were calculated, ∆E00 values and CIEL*a*b* individual color coordinates were compared for each pair of variables using the Student t test or Welch test (α = .05). RESULTS: Greater ∆E00 values were generally observed in the condition 3 for cervical limit (∆E00 = 10.7), use of zinc oxide and eugenol and mineral trioxide aggregate-based filling materials (∆E00 = 10.7), and anterior teeth (∆E00 = 12.4). Only in the condition 1, the ∆E00 values of the filling materials did not show statistical differences (P = .198). CONCLUSIONS: Higher ∆E00 values were yielded from zinc oxide and eugenol and mineral trioxide aggregate-based filling materials, anterior teeth, and dental cervix cervical limit of root filling. CLINICAL SIGNIFICANCE: Tooth discoloration yielded by endodontic materials and procedures is a challenge to clinical practice resulting in aesthetic problems and discomfort to both patient and professional, especially when it occurs in anterior teeth.

Influence of foraminal enlargement on the healing of periapical lesions in rat molars.

OBJECTIVES: The aim of this study was to evaluate the influence of foraminal enlargement on the healing of induced apical periodontitis in a rat model. MATERIAL AND METHODS: Periapical lesions were bilaterally induced in mandibular first molars of 24 Wistar rats, through root canals exposure to the oral environment during 3 weeks. Endodontic treatment was performed in the mesial canal of right molars, which were separated into two experimental groups (n = 12/group). The foraminal enlargement group (FEG) received instrumentation in the entire root canal length, including the cemental canal, while in the non-foraminal enlargement group (NFEG), instrumentation was carried out 1 mm short of the apical foramen. Root canals were filled with gutta-percha and AH Plus sealer, in the same visit, 1 mm short of the apical foramen in both experimental groups. Left molars were not treated and served as a baseline control group. The animals were killed after 4 weeks, and their hemi-mandibles were prepared for radiographic and histological analysis. Data were analyzed by Student's t test and ANOVA. RESULTS: Only FEG presented lower areas of periapical radiolucency compared to the control (p < .05). Both FEG and NFEG allowed decreased inflammation intensity (p < .0001 and p < .01) and higher scores of cementum neoformation when compared to non-treated samples (p < .0001). FEG was more effective than NFEG in promoting biological seal, i.e., apical closure with cementum (p < .01). FEG, but not NFEG, showed lower scores of root resorption than the control. CONCLUSIONS: Foraminal enlargement during root canal preparation improved periapical healing in rat molars. CLINICAL SIGNIFICANCE: Foraminal enlargement has been suggested to improve disinfection at the apical portion of root canals. This procedure may favor the healing of chronic periapical lesions.

Correction to: Influence of foraminal enlargement on the healing of periapical lesions in rat molars.

Figures 2 and 3 in the published version of this article contained a mistake. CCP and DCP should have been FEG and NFEG. Correct figures are presented here.

The effect of EDTA on the antibacterial activity of sodium hypochlorite.

The combination of ethylenediaminetetraacetic acid (EDTA) and sodium hypochlorite (NaOCl) has been suggested as an irrigant for root canal therapy. However, the chemical interaction between these agents is a complex subject that is not completely understood. The aim of this study was to evaluate the interference of an EDTA chelating agent in the antibacterial ability of NaOCl, while also considering variations in methodology. Various concentrations of NaOCl and EDTA solutions were prepared from 6% and 17% solutions, respectively. The antibacterial potential of pure solutions and their combinations was assessed using a direct contact test against Enterococcus faecalis. In the first experiment, NaOCl and EDTA solutions were mixed 5 minutes before the addition of the E faecalis bacterial suspension. In the second experiment, both solutions were simultaneously put in contact with the bacterial suspension. Data were submitted to a Spearman correlation coefficient and chi-square test. Results indicated that growth of E faecalis was significantly dependent on the solution-mixing method. In the first experiment, high concentrations (17% and 8.5%) of EDTA prevented the complete killing of E faecalis by 6% NaOCl at all experimental timepoints. In the second experiment, all concentrations of NaOCl were able to eliminate E faecalis, even in the presence of EDTA. In conclusion, when NaOCl and EDTA were added simultaneously to a bacterial suspension without premixing, NaOCl was able to exert its full bactericidal action.

Root canal preparation in 3-rooted maxillary premolars through hand, rotary, and reciprocating techniques: a microcomputed tomography evaluation.

Endodontic management of 3-rooted maxillary premolars is a challenge due to their complex anatomy and narrow root canal walls. This study aimed to evaluate, by microcomputed tomography (µCT), the apical enlargement and centering ability promoted by hand, rotary, and reciprocating instrumentation in 3-rooted maxillary premolars. Eighteen teeth were divided into 3 groups (n = 6) according to the preparation technique: crown-down hand, rotary, and reciprocating instrumentation. Instruments with similar apical diameters were used (25 and 40 mm for buccal and palatal canals, respectively). Centering ability and canal enlargement were evaluated through the comparison of µCT images obtained before and after instrumentation. Distances of 0, 2, 4, and 6 mm from the apical stop were considered. Differences between canal areas before and after instrumentation were calculated. In addition, distances between the original canal center and the prepared canal center at the apical stop were measured in both the mesiodistal and buccopalatal directions. Significant differences in enlargement areas and centering ability among the techniques were determined using 2-way analysis of variance and Tukey post hoc test (P > 0.05). Root canal enlargement was similar for all techniques. Excessive enlargement was observed in only a few specimens, and root perforation did not occur. Some specimens presented untreated canal areas. In mesiobuccal and distobuccal roots, reciprocating instrumentation promoted more centered preparations than hand instrumentation when measured in the mesiodistal direction (P > 0.05). There were no other statistically significant differences. The results established that hand, rotary, and reciprocating techniques presented similar safety margins for instrumentation of the apical third of 3-rooted maxillary premolars. Reciprocating instrumentation presented some advantages over hand preparation regarding centering ability.

Premixed calcium silicate-based root canal sealers have better biological properties than AH Plus: A systematic review and meta-analysis of in vivo animal studies and in vitro laboratory studies.

Objectives: The aim was to determine whether premixed calcium silicate-based root canal sealers have better biological properties than AH Plus. Materials and Methods: Searches of studies published up to January 2023 were performed in the PubMed/MEDLINE and EMBASE and via other methods (databases of the International Endodontic Journal, Journal of Endodontics, and gray literature). The inclusion criteria were in vivo animal and in vitro studies that analyzed the response in the dorsal subcutaneous tissue of rats, cell viability, and genotoxicity. Systematic Review Centre for Laboratory Animal Experimentation Risk of Bias (RoB) tool for in vivo studies and modified CONSORT checklist for in vitro were appraised. Meta-analysis was performed using the Stata. Results: Fifty-two studies were included. In the RoB, in vivo studies fulfilled 20%-50% of the items and in vitro 60%-100%. The studies included in the meta-analysis demonstrated better histocompatibility with the premixed calcium silicate-based sealers at 30 days and greater cell viability with these sealers when used in undiluted extracts in experimental period of 72 h and in extracts with 1:2 and 1:4 dilution in 24 and 72 h. In contrast, no difference between materials was found concerning genotoxicity. Conclusion: Premixed calcium silicate-based root canal sealers have better histocompatibility and are less cytotoxic than the epoxy resin-based sealer AH Plus, demonstrating favorable biological behavior.

Pain, anxiety, and catastrophizing among pregnant women with dental pain, undergoing root canal treatment.

This prospective study aims to evaluate dental pain, anxiety, and catastrophizing levels in pregnant women undergoing root canal treatment. Sixty pregnant and non-pregnant women presenting dental pain and an indication for root canal treatment were included in the study. Dental anxiety and catastrophizing were investigated using validated questionnaires. The endodontic intervention was performed, and a numerical scale measured preoperative and postoperative dental pain. The results were analyzed using STATA software 12.0. Unadjusted analyses assessed the association between pregnancy and pain, anxiety, and catastrophizing levels. Multiple linear regression models using 'forward stepwise' entry procedures were used to assess the independent effects of variables on pain scores. The significance level was set at 0.05. Initially, most patients experienced intense dental pain. The levels of dental pain, dental anxiety, and catastrophizing did not differ between pregnant and non-pregnant women. Logistic regression showed that postoperative pain was associated with irreversible pulpitis diagnosis (OR = 4.78; 95%CI 1.55-13.55) and high catastrophizing levels (OR = 1.96; 95%CI 1.01-3.84). Preoperative and postoperative pain rates and anxiety and catastrophizing were similar between pregnant and non-pregnant patients. Postoperative pain was associated with irreversible pulpitis diagnosis and high catastrophizing levels. The similarity between pregnant and non-pregnant women regarding preoperative and postoperative dental pain and catastrophizing and anxiety levels supports the indication of root canal treatment during the gestational period whenever necessary.

Tooth discoloration induced by endodontic sealers and cervical limit: 1-year in vitro evaluation.

This laboratory study aimed to evaluate the influence of endodontic sealer and cervical limit of root filling on the discoloration of root canal treated teeth. Bovine incisors were randomly distributed into six experimental groups and control (n=21/group), according to the endodontic sealer used [AH Plus (AP); MTA Fillapex (MF) and Sealer Plus BC (SPB)] and the cervical limit of root filling [dental cervix (DC) or 2 mm in apical direction (2mm-AD)]. Tooth discoloration (ΔE) was evaluated by a digital spectrophotometer using the CIED2000 method. Color assessments were performed immediately before (baseline), 1 week, 1, 3, 6 months, and 1 year after obturation. Data were analyzed by ANOVA and Tukey's post-hoc tests (α=5%). Teeth filled with the three sealers showed perceptible tooth discoloration (ΔE≥2.7) in 1 week, maintaining similar values over time. There was a significant difference between MF and SPB sealers in the 2mm-AD groups. In addition, 2mm-AD groups promoted significantly lower discoloration than DC groups for AH (3 months) and SPB (1 and 3 months) sealer,s. Teeth filled with AP, MF, and SPB sealers displayed discoloration from 1 week to one year, with differences between MF and SPB sealers. A cervical limit of filling material at 2 mm from the dental cervix seems more advisable, promoting lower crown discoloration.

Influence of height discrepancy between pulp chamber floor and crestal bone in the mechanical fatigue performance of endodontically-treated teeth restored with resin composite endocrowns.

OBJECTIVE: To explore and characterize the effect of the discrepancy between crestal bone height (CB) and pulp chamber floor (PCF) in the fatigue performance of endodontically-treated teeth rehabilitated with an endocrown restoration. MATERIALS AND METHODS: A total of 75 human molars free of defects, caries history or cracks were selected, then endodontically treated and randomly allocated into 5 groups (N = 15) according to the difference between PCF and CB, as follows: PCF 2 mm above, PCF 1 mm above, PCF leveled, PCF 1 mm below and PCF 2 mm below. Endocrown restorations were made with composite resin (Tetric N-Ceram, shade B3, Ivoclar) in 1.5 mm thickness and luted with a resin cement (Multilink N, Ivoclar) onto the dental elements. Monotonic testing was performed to define the fatigue parameters, and a cyclic fatigue test was used until failure of the assembly. The collected data were submitted to statistical survival analysis (Kaplan-Meier followed by Mantel-Cox and Weibull), fractographic analysis and finite element analysis (FEA) were performed as complementary analyzes. RESULTS: The PCF 2 mm below and PCF 1 mm below groups presented the best results regarding fatigue failure load (FFL) and number of cycles for failure (CFF) (p < 0.05), but presented no difference between each other (p > 0.05). The PCF leveled and PCF 1 mm above groups presented no statistical difference between them (p > 0.05), but performed better than the PCF 2 mm above group (p < 0.05). The rate of favorable failures of PCF 2 mm above, PCF 1 mm above, PCF leveled, PCF 1 mm below and PCF 2 mm below groups were 91.7%, 100%, 75%, 66.7% and 41.7%, respectively. FEA showed different stress magnitudes according to the pulp-chamber design. CONCLUSION: The insertion level of the dental element to be rehabilitated with an endocrown interferes in the mechanical fatigue performance of the set. The discrepancy between the CB height and the PCF has a direct effect, where the higher the PCF in relation to the CB, the greater the risk of mechanical failure of the restored dental element.

Pulp sensibility test in elderly patients.

BACKGROUND: The ageing process transforms the histological composition of the dental pulp and may affect the response to pulp sensibility tests. OBJECTIVES: The aim of this study was to assess the influence of age on pulp response time and on pain intensity. MATERIAL AND METHODS: Fifty elderly patients and 50 young patients were selected. Different classes of teeth were evaluated. The pulp sensibility test was performed with a refrigerant spray. The pulp response time was measured in seconds and the pain intensity was assessed by visual analogue scale. RESULTS: The Spearman coefficient was calculated and detect a positive correlation between age and pulp response time for maxillary incisors, premolars, mandibular incisors, and mean (p < 0.05). On the contrary, there was a negative correlation between age and pain intensity for maxillary incisors, mandibular incisors, and mean (p < 0.05). Also, the results of elderly and young groups were compared by Mann-Whitney test. Significant difference was noted regarding the pulp response time for maxillary incisors, premolars, mandibular incisors, and mean (p < 0.05). Significant difference was detected regarding the pain intensity for mandibular incisors only (p < 0.05). CONCLUSIONS: Pulp response time increases when people get older while pain intensity decreases. There were variations among the classes of teeth.

Factors related to apical periodontitis in a southern Brazilian population: a multilevel analysis.

The aim of this cross-sectional study was to evaluate the effects of individual-level and tooth-level factors on apical periodontitis (AP) in an urban population in southern Brazil. A random sample of digital panoramic radiographs (n = 545) from a dental school database was evaluated. The diagnosis of AP was determined by using a dichotomous scale (yes/no). AP was assessed according to gender, age, presence and quality of endodontic treatment (ET), presence of an intracanal post, coronal condition, and dental group. Data were analyzed descriptively and through multilevel Poisson regression analysis, considering teeth characteristics (level 1) nested in individuals (level 2). In this sample of 545 participants, the prevalence of AP was 49.5% (n =2 70) and ET was 43.5% (n = 237). Considering 13,595 teeth, AP was identified in 596 (4.4%) and ET in 617 (4.5%). Of the teeth with ET, 153 (24.8%) presented AP. Among individual-level factors, the disease was not significantly associated with gender or age. For tooth-level factors, AP was significantly associated with ET quality: teeth with short fillings (< 3 mm) and teeth with over-fillings had 2.77 (CI: 1.95-3.94, p < 0.001) and 1.08 (CI: 0.39-2.98, p < 0.001) higher prevalence of AP, respectively. There was no association between AP and age, gender, dental group, coronal condition, or the presence of an intracanal post. AP was highly prevalent in this population, and multilevel analysis indicated a significant association with ET quality.

Toxicity of bioceramic and resinous endodontic sealers using an alternative animal model: Artemia salina.

Aims: The present study assessed the toxicity of a novel calcium silicate-based root canal sealer (Bio-C Sealer) in comparison to Endosequence BC Sealer and AH Plus through a lethality assay involving brine shrimp (Artemia salina). Methods: Brine shrimp cysts were incubated for 24 h for the hatching of the larvae, which were then exposed to different concentrations (2.5, 5, 10, 20, 40, 80, and 100 µg/mL) of the test endodontic sealers for 24 h, followed by the determination of the survival rate. Statistical Analysis Used: One-way repeated-measures ANOVA and the Newman-Keuls post hoc test were used to compare the different materials as well as different concentrations of the same material. Dunnett's test was used to compare the different concentrations and different sealers to the control. The lethal concentration of each endodontic sealer necessary to kill 50% of the brine shrimp larvae (LC50) was also determined. Results: The toxicity of Bio-C (10, 20, 40, 80, and 100 µg/mL) and Endosequence BC Sealer (20, 80, and 100 µg/mL) was lower than that of AH Plus. No significant difference was found between Bio-C and Endosequence BC Sealer or among the different intragroup concentrations of these sealers. In the AH Plus group, concentrations ≥5.0 µg/mL exhibited greater toxicity compared to the concentration of 2.5 µg/mL and the control. AH Plus had the lowest LC50 (59.95 µg/mL), whereas Bio-C and Endosequence BC Sealer had LC50 values >200 µg/mL. Conclusions: Bio-C Sealer proved to be less toxic than AH Plus and exhibited similar toxicity to that of Endosequence BC Sealer.

Does ultrasonic activation improve the bond strength and root canal filling quality of endodontic sealers?

This study aimed to investigate the effect of ultrasonic activation (UA) of three endodontic sealers on the bond strength to root dentin and root canal filling quality. Ninety six bovine incisors were instrumented and root canal filling was carried out using AH Plus (AP), Sealer Plus (SP), or Sealer Plus BC (BC), with or without UA (n=16/group). Two 1.5-mm slices were obtained from each root third. The first slice was subjected to push-out testing and failure mode analysis, while the second was observed under a stereomicroscope for filling quality assessment. Data were analyzed by Kruskal-Wallis, Mann-Whitney and Friedman tests (α=0.05). SP showed higher bond strength and fewer voids than BC in the apical third and when root thirds data were pooled. SP also had higher bond strength compared with AH Plus in the apical third. UA improved the bond strength when BC was used but did not affect the filling quality of any sealer. There were no significant differences between the ultrasonically activated sealers regarding bond strength and filling quality. When root thirds were compared, the bond strength was similar along the root, but there was a tendency to worsen filling quality, with more voids, in the apical segment. In conclusion, UA was effective in increasing the bond strength of the calcium silicate-based sealer but did not improve its filling quality. For the epoxy resin-based sealers, these properties were not affected by UA.

Postoperative pain after endodontic reintervention: a randomized clinical trial.

The present randomized clinical trial compared the prevalence and intensity of postoperative pain in cases of endodontic reintervention using manual or engine-driven reciprocating instruments. As secondary objectives, the analgesic intake and time required for the root canal filling removal and re-instrumentation were also evaluated. Forty-eight individuals with an endodontically treated single-rooted tooth diagnosed with asymptomatic apical periodontitis were included in the study. Patients were randomly assigned to two comparison groups (n=24/group): reintervention with stainless steel manual instruments or a nickel-titanium reciprocating system (Reciproc; VDW, Munich, Germany). The endodontic reintervention was performed in two sessions with a calcium hydroxide-based intracanal medication applied for 14 days before root canal obturation. Working time for the root canal filling removal and re-instrumentation was recorded with a digital stopwatch. After each visit, postoperative pain intensity was assessed at 12, 24, and 48 hours and seven days using the Numerical Rating Scale (NRS). The patients were also asked about analgesic intake. Data were analyzed using Pearson chi-square, T and Mann-Whitney U tests (α=0.05). No significant differences between groups were found regarding the prevalence and intensity of pain or the need for analgesic intake at any time point (P > 0.05). Working time was significantly shorter in the reciprocating group (18 versus 41 minutes). In conclusion, manual and reciprocating instruments achieved the same results in terms of prevalence and intensity of postoperative pain and analgesic intake. However, filling material removal and re-instrumentation of the root canals were more than twice as fast when using the reciprocating system.

O objetivo deste ensaio clínico randomizado foi comparar a prevalência e a intensidade da dor pós-operatória em casos de retratamento endodôntico, utilizando instrumentos manuais ou reciprocantes (automatizados). O tempo necessário para desobturação e reinstrumentação do canal radicular também foi avaliado. Quarenta e oito indivíduos possuindo um dente unirradicular tratado endodonticamente e portador de periodontite apical assintomática foram incluídos no estudo. Os pacientes foram aleatoriamente distribuídos em dois grupos (n=24/grupo): retratamento com instrumentos manuais de aço inoxidável ou um sistema reciprocante de níquel-titânio (Reciproc; VDW, Munique, Alemanha). A reintervenção endodôntica foi realizada em duas consultas, sendo aplicada medicação intracanal à base de hidróxido de cálcio por 14 dias, antes da obturação. O tempo clínico gasto com os protocolos de desobturação e reinstrumentação do canal radicular foi registrado com um cronômetro digital. Após cada visita, a intensidade da dor pós-operatória foi avaliada em 12, 24, 48 horas e 7 dias por meio da escala de estimativa numérica (Numerical Rating Scale - NRS). Além do registro da dor, os pacientes foram questionados quanto ao uso de analgésicos. Os dados obtidos foram analisados por testes Qui-quadrado e Mann-Whitney (α=0.05). Não foi detectada diferença significativa entre os grupos quanto à prevalência e intensidade da dor ou uso de analgésicos em nenhum dos períodos avaliados. O tempo clínico foi significativamente menor no grupo reciprocante (18 versus 41 minutos). Pode-se concluir que os instrumentos manuais e reciprocantes foram equivalentes quanto à prevalência e intensidade de dor pós-operatória e uso de analgésicos, mas a desobturação e reinstrumentação do canal radicular foram duas vezes mais rápidas com o sistema reciprocante.

Outcome of endodontic treatments performed by Brazilian undergraduate students: 3- to 8-year follow up.

Objectives: This study aimed to evaluate the success rate of endodontic treatments performed by undergraduate students and the factors associated with the outcome. Materials and Methods: A follow-up of 3 to 8 years after root canal filling was carried out in 91 patients. At the follow-up visits, medical and dental history questionnaires were applied along with clinical and radiographic examinations. Data collected in the clinical exam included: the presence of pain, swelling, sinus tract, mobility, tenderness to palpation and percussion, periodontal probing profile, and type/quality of coronal restoration. Postoperative and follow-up radiographs were digitalized and analyzed by 2 trained and calibrated examiners to assess periapical healing. The treatment outcome was based on strict clinical and radiographic criteria and classified as success (absence of any clinical and radiographic sign of apical periodontitis) or failure (other combination). Logistic regression was used to investigate the impact of clinical and radiographic variables on endodontic treatment outcomes at a 5% significance level. Results: The success rate of endodontic treatments was 60.7%. The only risk factor significantly associated with failure was the presence of a periapical lesion on the postoperative radiograph (odds ratio, 3.35; 95% confidence interval, 1.17-9.54). Conclusions: The success rate of endodontic treatments performed by undergraduate students was low and was jeopardized by the presence of a periapical lesion on the postoperative radiograph.

Influence of Root Canal Preparation on Formation of Dentinal Microcracks: A Systematic Review.

The effect of root canal preparation technique on microcrack initiation is a controversial issue. This systematic review aimed to assess the role of root canal preparation techniques with different kinematics (manual, rotary, reciprocating, adaptive, self-adjusting file) on microcrack initiation. In vitro and in situ studies comparing the influence of at least two different root canal preparation techniques on the initiation of dentin microcracks were searched in PubMed/MEDLINE and SCOPUS up to June 5, 2018 without language and period restriction. Two authors independently reviewed all identified titles and abstracts for eligibility. Tables were generated to summarize the included studies, and the included studies were assessed for bias. Fifty-four (n=54) articles met the eligibility criteria. The results were classified according to the method used for microcrack evaluation, and most studies that used micro-computed tomography showed no formation of new cracks after root canal preparation. In general, the instrumentation techniques induced microcrack formation when the methods were destructive, irrespective of kinematics. In relation to the apex region, when the preparation working length was set as the root canal length subtracted of 1 mm, the risk of microcrack initiation reduces. The majority of the included studies had low risk of bias for all assessed domains. Our results seem to indicate that the various root canal preparation techniques considered in this study will not cause damage to the dental structure when adequately employed and the proper methodology is applied.

Detectability of Middle Mesial Canal in Mandibular Molar After Troughing Using Ultrasonics and Magnification: An Ex Vivo Study.

The aim of this study was to evaluate the frequency of the identification of middle mesial (MM) canals in extracted permanent first and second mandibular molars before and after executing a troughing technique with high magnification. Sample consisted of 105 mandibular molars. After gaining access to the pulp chamber and cleaning the chamber floor, root canals were detected in three different stages. The initial location was performed under direct viewing without magnification. In the second stage, a dental operating microscope was employed at 12 magnification. If the MM canal was not observed, a standardized troughing technique was executed with the use of an ultrasonic tip between the mesiobuccal and mesiolingual canals under magnification. Statistical differences in the frequency of MM canals before and after troughing were determined using McNemar's test, with the significance level set at 5%. No significant increase in the identification of the MM canal was found when comparing observations before (9.52%) and after (12.38%) the troughing technique under high magnification. However, viewing under magnification and the execution of troughing significantly increased the location of the MM canal (12.38%) when compared to viewing without magnification (3.81%) (p<0.01). The troughing technique with the aid of a dental operating microscope significantly improved the identification of MM canals compared to viewing without magnification. Troughing is a safe, minimally invasive procedure that benefits the treatment of mandibular molars.