Computerized Generation and Finite Element Stress Analysis of Endodontic Rotary File

Introduction: The finite element method has been extensively used to analyze the mechanical behavior of endodontic rotary files under bending and torsional conditions. This methodology requires elevated computer-aided design skills to reproduce the geometry of the endodontic file, and also mathematical knowledge to perform the finite element analysis. In this study, an automated procedure is proposed for the computerized generation and finite element analysis of endodontic rotary files under bending and torsional conditions. Methods: An endodontic rotary file with a 25mm total length, 0.25mm at the tip, 1.20mm at 16mm from the tip, 2mm pitch and squared cross section was generated using the proposed procedure and submitted for analysis under bending and torsional conditions by clamping the last 3mm of the endodontic rotary file and applying a transverse load of 0.1N and a torsional moment of 0.3N⋅cm. Results: The results of the finite element analyses showed a maximum von Mises stress of 398MPa resulting from the bending analysis and a maximum von Mises stress of 843MPa resulting from the torsional analysis, both of which are next to the encastre point. Conclusions: The automated procedure allows an accurate description of the geometry of the endodontic file to be obtained based on its design parameters as well as a finite element model of the endodontic file from the previously generated geometry

Green discoloration of the crown after internal root resorption treatment with grey mineral trioxide aggregate (MTA)

Root resorption (RR) is the loss of dental hard tissues as a result of clastic activities. Internal inflammatory root resorption (IRR) is a type of RR characterized by progressive loss of tooth substance starting from the root canal wall. IRR is usually asymptomatic, slowly progressing, and detectable upon routine radiographic examination or by the clinical sign of a ‘pink spot’ when the IRR involves the crown or the coronal third of the root canal. Mineral trioxide aggregate (MTA) is a biocompatible cement that has been used successfully in pulp capping, pulpotomy, treatment of traumatized teeth with immature apices, and for treatment of root resorption. The treatment and follow-up of a maxillary central incisor with perforating IRR managed by root canal treatment and grey MTA repair is reported. IRR affected tooth 11 (FDI World Dental Federation) in a 29-year-old female patient, with a history of previous trauma. Follow-up radiographs over 24 months demonstrated the maintenance of a functional tooth. However, the tooth showed a green discoloration of the crown after MTA treatment

Postoperative pain after one-visit root-canal treatment on teeth with vital pulps : comparison of three different obturation techniques

Objectives. To investigate and compare postoperative pain after one-visit root canal treatment (RCT) on teeth with vital pulps using three different obturation techniques. Study Design. Two hundred and four patients (105 men and 99 women) aged 12 to 77 years were randomly assigned into three treatments groups: cold lateral compaction of gutta-percha (LC), Thermafil technique (TT), and Backfill - Thermafil obturation technique (BT). Postoperative pain was recorded on a visual analogue scale (VAS) of 0 - 10 after 2 and 6 hours, and 1, 2, 3, 4, 5, 6 and 7 days. Data were statistically analyzed using multivariate logistic regression analysis. Results. In the total sample, 87% of patients experienced discomfort or pain in some moment between RCT and the seventh day. The discomfort experienced was weak, light, moderate and intense in 6%, 44%, 20% and 6% of the cases, respectively. Mean pain levels were 0.4 ± 0.4, 0.4 ± 0.3, and 1.4 ± 0.7 in LC, BT, and TT groups, respectively. Patients of TT group experienced a significantly higher mean pain level compared to other two groups (p < 0.0001). In TT group, all patients felt some level of pain at six hours after RCT. Conclusions. Postoperative pain was significantly associated with the obturation technique used during root canal treatment. Patients whose teeth were filled with Thermafil obturators (TT technique) showed significantly higher levels of discomfort than patients whose teeth were filled using any of the other two techniques

Pregabalin in the treatment of inferior alveolar nerve paraesthesia following overfilling of endodontic sealer

A case of orofacial pain and inferior alveolar nerve (IAN) paraesthesia after extrusion of endodontic sealer within the mandibular canal treated with prednisone and pregabalin is described. A 36-year-old woman underwent root canal treatment of the mandibular second right premolar tooth. Post-operative panoramic radiograph revealed the presence of radiopaque canal sealer in the mandibular canal. Damage to IAN consecutive to extrusion of endodontic sealer was diagnosed. Non-surgical management was decided, including: 1 mg/kg/day prednisone 2 times/day, once-daily regimen, and 150 mg/day pregabalin, two doses per day, monitoring the progress with periodic follow-up visits. Six weeks after the incident the signs and symptoms were gone. The complete resolution of paraesthesia and the control of pain achieved suggest that a non-surgical approach, combining prednisone and the GABA analogue pregabalin, is a good option in the management of the IAN damage subsequent to endodontic sealer extrusion

Effect of the methacrylate-based endodontic sealer Epiphany on rat peritoneal macrophages viability

Objective: To evaluate the effect of the endodontic sealer Epiphany on rat peritoneal macrophages viability. Materials and methods: Peritoneal macrophages were obtained from Wistar rats and resuspended in RPMI- 1640 medium. Undiluted (crude extract) and diluted extracts to 10%, 1%, 0.1%, 0.01%, 0.001% and 0.0001% of Epiphany, AH 26 and AH Plus sealers on RPMI-1640 medium were tested for cytotoxicity to rat peritoneal macrophages using the trypan blue dye exclusion assay. Data were analyzed statistically by the Kruskal-Wallis and Mann-Whitney tests at 5% significance level. Results: Crude extract of Epiphany killed 51% of cells, but was less cytotoxic that crude extracts of AH Plus and AH 26, which killed 81% and 86% of cells, respectively. Ten-fold dilutions of Epiphany, AH Plus and AH 26 killed 44%, 56%, 62% of macrophages, respectively. A hundred dilution of Epiphany only killed 7% of macrophages, but the same dilution of AH Plus and AH 26 killed 10% and 31% of macrophages, respectively. Lower dilutions of sealer extracts caused minimal cell death as compared to the control groups (p>0.05). Conclusions: The methacrylate-based endodontic sealer Epiphany showed lower cytotoxicity on macrophages than resin-based sealers AH Plus and AH 26. Dilution of elutes of the three materials by tenfold markedly reduced their effect

Alergia, respiración oral y mordida cruzada, ¿una triada?

Background:The respiratory allergy in children is a disease that occurs in our midst with a prevalence above 30% and an annual incidence is increasing. The association of respiratory allergy in children and certain stomatological alterations have been demonstrated in numerous studies. Objectives: We studied a sample of pediatric patients in our environment in which we intend to observe, if any, relationship between allergic disease in upper airway, the habit oral breathing as a cause of decreased transverse diameter of the upper jaw as a cause of posterior crossbite. Methods: Data of all pediatric patients aged between 1 and 15 years attending the Clinic of Dentistry, Faculty of Health Sciences and Sport (University of Zaragoza, Huesca) were collected between 2010 and 2014; in the survey collects age, sex, allergies diagnosed by your doctor that course with rhinoconjunctivitis, oral breathing or crossbite. Results: Draws attention to the large differences in the percentages of allergic patients with oral breathing, 81%, compared with 20% of non-allergic patients who breathe buccally. Crossbite also observed in 17.4% of allergic patients versus 5.29% of non-allergic patients with crossbite, is another fact to be taken into account. Conclusions: Pediatric patients allergic show a predisposition to oral breathing, and significantly increases the risk of crossbite.Antecedentes: La alergia respiratoria en pediatría es una patología que se presenta en nuestro medio con una prevalencia superior al 30% y una incidencia anual que va en aumento. La asociación de la alergia respiratoria en la edad pediátrica y determinadas alteraciones estomatológicas ha sido demostrada en numerosos estudios. Objetivos: Estudiamos una muestra de pacientes en edad pediátrica de nuestro medio en la que pretendemos observar, si lo hubiera, una relación entre la patología alérgica en vías respiratorias altas, con el hábito respirador oral como causa de la disminución del diámetro transversal del maxilar superior como causa de mordida cruzada posterior. Material y método: Se recogen datos de todos los pacientes pediátricos de edades comprendidas entre los 1 y los 15 años que acuden a la Clínica de Odontología de la Facultad de Ciencias de la Salud y del Deporte (Universidad de Zaragoza, ciudad de Huesca) entre los años 2010 y 2014; en la encuesta se recoge la edad, el sexo, las alergias diagnosticadas por su pediatra que cursen con rinoconjuntivitis, respiración bucal o mordida cruzada. Resultados: Llama especialmente la atención las grandes diferencias en los porcentajes de pacientes alérgicos con respiración oral, un 81%, en contraste con el 20% de los pacientes no alérgicos que respiran bucalmente. También la mordida cruzada que se observa en el 17,4% de los pacientes alérgicos, frente al 5,29% de los pacientes no alérgicos con mordida cruzada, es otro dato que debe tenerse en cuenta. Conclusiones: Los pacientes pediátricos alérgicos muestran una gran predisposición a presentar respiración bucal, así como se incrementa significativamente el riesgo de padecer mordida cruzada