Investigation of the thermal and physicochemical behavior of two types of gutta-percha cones for back-filling the root canal.

Background: Gutta-percha (Gp) is an inert thermoplastic polymer used as a filling to replace the dental pulp space, which has been reformulated to improve its three-dimensional sealing properties. Therefore, this study aimed to analyze the physical, chemical and thermal properties of two types of gutta-percha filling. As well as measuring the temperature distribution along the cone at the time of cutting through an in-situ test. Material and Methods: Two commercially available brands of gutta-percha point were investigated: Conform Fit TM Gutta-Percha for ProTaper Gold® (PTG) (Dentsply Sirona), and Hygenic Gutta-Percha (Coltene whaledent). Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were selected for the thermal characterization of materials, and Fourier Transform Infrared Spectroscopy (FT-IR) for the chemical analysis of Gp cones. Regarding temperature distribution, it was evaluated using a thermographic camera (FLIR ONE® PRO by MicroUSB P/N 435-0011-01) at 0 to 20 s after the cutting process (n=11/group). Results: Both materials have three fusion endotherms associated with the three crystalline phases of Gp, with similar temperatures but enthalpies that differ by 60%, the fusion enthalpy being higher for Conform Fit. In the chemical characterization, elements such as Zn, C, O, Ba, S and Si were found in both materials but in different proportions. Regarding the content of fillers, the Conform Fit presented around 30% of Gp polymer and 25% for the Hygenic. The morphological characterization shows a microtexturized coating in the form of bars on a micrometric scale for the Conform Fit, which could favor a better three-dimensional seal. In addition to that, in heat transfer studies they showed greater temperature control. Conclusions: The characterization of the materials allowed us to see the variation in terms of their composition and configuration to the Gp cones of two commercial brands. These variations directly modify the thermal behavior of the material. Key words:Gutta-percha, Conform Fit, Infrared thermography, Differential Scanning Calorimetry, Infrared Spectroscopy.

Evaluation of Apical Transportation by Three Rotary Systems in Extracted Teeth with Curved Canals / Evaluación de la transportación apical con tres sistemas rotatorios en dientes extraídos con conductos curvos

Abstract The aim of this study was to compare the apical transportation in extracted teeth using three different rotary nickel-titanium systems (Mtwo, Hyflex CM, and Typhoon). Sixty extracted first molars were randomly divided into three groups (n=20 in each group) with similar root canal curvatures (25-52 degrees). All root canals were prepared to size 30 using a crown-down preparation technique for each rotary system. Loss of working length and apical transportation were determined by X-ray evaluation. Comparisons between the groups were performed using one-way analysis of variance (ANOVA) or Kruskal-Wallis tests, and the post hoc analyses employed were Dunn´s or Tukey´s multiple comparison tests. No significant differences were detected between the different rotary systems in the loss of working length and apical transportation. This in vitro study showed that the use of these three rotary systems are safe and useful for instrumentation in curved canals; however, further in vivo research is essential to compare the effectiveness and safety of these systems for use in curved canals.

Resumen El objetivo del presente estudio fue comparar la transportación apical en dientes extraídos utilizando tres sistemas rotatorios de níquel-titanio (Mtwo, Hyflex CM y Typhoon). Sesenta primeros molares extraídos se dividieron aleatoriamente en tres grupos (n=20 en cada grupo) con curvaturas del conducto radicular similares (25-52 grados). Todos los conductos radiculares se prepararon usando una técnica corono apical para cada sistema rotatorio. La pérdida de la longitud de trabajo y la transportación apical se determinaron mediante evaluación radiográfica. Las comparaciones entre los grupos se realizaron utilizando análisis de varianza de una vía (ANOVA) o Kruskal-Wallis, y los análisis post hoc empleados fueron las pruebas de comparación múltiple de Dunn o Tukey. No se detectaron diferencias significativas entre los diferentes sistemas rotatorios en la pérdida de la longitud de trabajo y transportación apical. Este estudio demostró que el uso de estos tres sistemas es seguro y útil para su instrumentación en conductos curvos; sin embargo, investigación in vivo es necesaria para comparar la efectividad y seguridad de estos sistemas para su uso en conductos curvos.

Macrophage migration inhibitory factor gene polymorphisms as exacerbating factors of apical periodontitis.

BACKGROUND: Two polymorphisms in the macrophage migration inhibitory factor (MIF) gene have been associated with inflammatory diseases (-794 CATT5-8 and -173G>C); however, so far there are no reports of studies related to oral health. OBJECTIVES: To genotype the -794 CATT5-8 and -173G>C MIF polymorphisms in Mexican patients with apical periodontitis as a genetic risk of exacerbation. MATERIAL AND METHODS: The study involved 120 patients with apical periodontitis: 60 with a diagnosis of acute apical periodontitis (Group A) and 60 without previous episodes of exacerbation (Group B). Allelic discrimination was performed from peripheral blood DNA; the repeat polymorphism -794 CATT5-8 was genotyped with sequencing, while the -173G>C polymorphism was determined using real-time polymerase chain reaction (RT-PCR) using TaqMan probes. The associations between MIF polymorphisms, haplotypes and the risk of exacerbated apical periodontitis were assessed. RESULTS: The allele CATT7 was associated with the risk of a stage of acute inflammation (OR = 4.13; 95% CI = 1.82-9.63; p =< 0.001). Regarding the -173G >C polymorphism, a process of inflammation exacerbation was only associated with the CC genotype (OR = 4.1; 95% CI = 1.02-20.84; p = 0.045). The analysis of the haplotype showed that the combination CATT7/C increases the risk of exacerbation of apical periodontitis (OR = 3.57; 95% CI = 1.038-13.300; p = 0.021). CONCLUSIONS: The polymorphisms -794 CATT5-8 and -173G>C MIF seem to significantly influence the development of a state of exacerbated inflammation in patients with apical periodontitis.

Bacterial Percolation and Sealer Tubular Penetration in a Polymer-based Obturation System Compared with Warm Vertical Condensation Technique: An in Vitro Study.

Introduction: This study compared bacterial percolation and sealer penetration of a novel obturation technique with the ones of warm vertical condensation technique. Methods and Materials: A bacterial percolation test was carried out with 80 single rooted human teeth divided into 5 groups; A (n=20): warm vertical condensation and AH-Plus, B (n=20): CPoint with AH-Plus, C (n= 20): CPoint with EndoSequence BC, +ve Control (n=10): teeth with no canal obturation, -ve Control (n=10): teeth with no access cavity. The samples were inoculated with a multispecies bacterial incoulum. Bacterial percolation was evaluated by turbidity. Confocal laser scanning microscopy (CLSM) was used to observe the presence of gaps and voids. Further 48 extracted human mandibular single-canal premolars were used to determine the sealer penetration. Slices of the samples were observed by CLSM to evaluate tubules penetration of the sealer. Kaplan Meyer survival, ANOVA one way and Tuckey HSD test and a Wilcoxon signed-rank test were utilised. Results: A Kaplan-Meier test showed no significant difference overall (P>0.05) between groups A, B and C. At 43 days, the group B showed a significantly inferior ability to prevent bacterial passage (P<0.05). The group C showed a deeper sealer penetration than group A and B with statistically significant differences (P<0.05) for the total penetration (ANOVA one way and Tukey HSD). A Wilcoxon signed-rank test showed statistically significant differences for the penetration in the middle-and apical third of the 3 groups. Conclusion: Based on this in vitro study, the single polymer-cone obturation technique with a resin based- and bioceramic based-sealer behaved similarly to the warm vertical obturation technique in preventing bacterial passage. The bioceramic sealer showed the deepest penetration but did not fully prevent bacterial leakage.

Evaluación de la microfiltración apical de BiodentineTM como material de obturación apical mediante el transporte de fluidos computarizado / Evaluation of the apical microleakage of BiodentineTM when used as an apical sealing material, using computerized fluid dynamics

Objetivo: evaluar la capacidad de BiodentineTM para resistir la microfiltración cuando es usado como material de retroobturación medianteun sistema de transporte de fluidos computarizado. Metodología: En este estudio se utilizaron 60 raíces de dientes unirradiculares, se instrumentaron y obturaron con el sistema de cono único estandarizadodel sistema ProTaper (Dentsply, Maillefer, Suiza) con ultrasonido,utilizando el sellador de conductos radiculares Silco (Silva-Collyan SLP,México). Se hizo la preparación de la cavidad retrógrada con ultrasonidoutilizando la punta E31D del sistema Retro Kit (NSK Company, Japón),con un diámetro de 2 mm. Se llevó a cabo la retroobturación con cada uno de los cementos a evaluar; grupo 1: bturados con Biodentine™ (Septodont, Francia), grupo 2: obturados con MTA Gris (Angelus™, Londrina PR, Brasil), grupo 3: control. Se utilizó un software creado específi camente para evaluar microfi ltración; éste, por medio de sensores infrarrojos, detecta la variación de voltaje de una burbuja de aire dentro de un capilar. El programa expresa el tiempo que tarda la burbuja en pasar por el segundo sensor (mm/min), los cuales se convierten a μL/min, para después expresarlos en unidades de fi ltración, realizándosemediciones en un solo lapso. Resultados: La evaluación en este estudio de la microfi ltración apical de Biodentine™ y MTA Gris Angelus™, arrojó resultados favorables para ambos; se comprobó que no existe diferencia signifi cativa en cuanto a la microfiltración entre ellos; sin embargo, ambos materiales mostraron diferentes características en cuanto a su manipulación, tiempo de fraguado y porosidad. No se presentódiferencia estadísticamente significativa entre los grupos (p = 0.256) U Mann-Whitney y Kruskal Wallis. Conclusión: El Biodentine™ y TA Gris AngelusTM presentan un comportamiento óptimo para la obturación retrógrada. Se requiere realizar otros estudios en cuanto a la interfase con la estructura dentinaria.

Objective: To evaluate, using computational fl uid dynamics, the ability of BiodentineTM to resist microleakage when used as a retro-sealing material. Methodology: In this study, 60 single-rooted teeth were used, which were biomechanically prepared and fi lled using the standardized ProTaper single-cone technique (Dentsply, Maillefer, Switzerland) and ultrasound, using Silco root-canal sealer (Silva-Collyan, SLP, Mexico). The retrograde cavity was prepared using ultrasound and a Retro Kit (NSK Company, Japan) E31D 2 mm-diameter tip. Retrograde fi lling was performed using each of the sealers to be evaluated, as follows: group 1: sealed with BiodentineTM (Septodont, France); group 2: sealed with Grey MTA (AngelusTM, Londrina PR, Brazil); group 3: control. A specially designed software was used, which measures microleakage by using infrared sensors to detect changes in voltage in an air bubble within a capillary tube. The software expresses the time it takes (mm/min) for the bubble to pass through the second sensor, then converts these measurements into μL/min to express the rate of leakage. All of the measurements are taken considering a single interval. Results: The results of the evaluation of the apical microleakage of BiodentineTM and MTA Grey AngelusTM obtained in this study were, in both cases, favorable, proving that there is no signifi cant difference between the two in this respect. However, the characteristics of each in terms of their handling, setting time, and porosity differed. No statistically signifi cant difference between the Mann-Whitney U group and the Kruskal-Wallis group was found (p = 0.256). Conclusion: The performance of Bio-dentineTM and Gray MTA AngelusTM is ideal for retrograde fi lling pur-poses. Further studies are needed, including SEM analysis, in order to determine the quality of the seal, with respect to the interface formed with the dentin structure.

Effectiveness of three electronic apex locators to determine root canal working length / Efectividad de tres localizadores apicales electrónicos para determinar la longitud radicular de trabajo

This study was to evaluate in vivo the accuracy of three electronic apex locators (EALs) in determining working length (WL) using hand files and a wear technique. Thirty two premolars that were completely formed apically and that were scheduled for extraction for orthodontic reasons from patients between ages of 15 and 20 years old were included. Electronic measurement of WL was performed using the EAL according to the manufacturer’s instructions. The following three EAL were used: A. Root ZX II; B. Raypex 5, and C. Propex II. There were significant difference (p=0.0002) when comparing median differences among the three EAL. Statistical analysis revealed significant differences between Root ZX II vs. Raypex 5 and Root ZX II vs. Propex II (p=0.0044; p=0.0002), while between aypex 5 and Propex II, there were no statistically significant differences with respect to the accuracy of the EAL in determining WL (p=0.1087). The present findings suggest that Root ZX II presented the highest agreement rate for determining the final WL...

Estudio fue evaluar in vivo la exactitud de tres localizadores apicales electrónicos(LAEs) para determinar la longitud de trabajo (LT) usando instrumentos manuales y una técnica de desgaste. Treinta y dos premolares con formación apical completa e indicados para extracción por razones ortodóncicas de pacientes de edad entre 15 y 20 años fueron incluidos en el estudio. Seusaron tres LAE; A. Root ZX II; B. Raypex 5, y C. Propex II. Se encontraron diferencias significativas (p=0.0002) cuando se compararon las medianas entre los tres LAE. El análisismostró diferencias entre Root ZX II vs. Raypex 5 y Root ZX II vs. Propex II (p=0.0044; p=0,0002), mientras queentre Raypex 5 y Propex II, no se encontraron diferencias estadísticamente significativas en la determinación de la LT (p=0.1087). Los presentes hallazgos sugieren que Root ZX II mostró la mayor exactitud para determinar la LT final...

Clinical efficacy of low level laser therapy in reducing pain and swelling after periapical surgery: a preliminary report / Eficacia clínica de láser terapéutico de bajo nivel de emisión en la reducción de dolor e inflamación posterior a cirugía periapical: reporte preliminar

The objective of this study was to evaluate the efficacy of the low level laser therapy (LLLT) in postoperative pain and swelling associated with periapical surgery. A double-blind, randomized, controlled clinical trial was carried out in 2 groups of 10 patients each, undergoing periapical surgery. The experimental group was treated with an intraoral application of an 810 nm-GaAsAl-laser, having an output power of 100 mW, with overlapping movements over the wound. In the control group, the same procedure was carried out, without therapeutic laser activation. Postoperative pain, swelling, and rescue medication were registered. The experimental group exhibited a decrease in pain intensity after periapical surgery compared with control group (p<0.05). There was not significant statistical difference between the groups in terms of swelling. Six patients of the control group required rescue medication. The use of LLLT in the postoperative management of patients having periapical surgery, using the protocol of this study reduced postoperative pain...

El objetivo del estudio fue evaluar la eficacia del láser terapéutico de bajo nivel de emisión (LTBNE) en el dolor postoperatorio e inflamación asociados con cirugía periapical. Se realizó un ensayo clínico controlado aleatorizado doble ciego en 2 grupos de 10 pacientes cada uno, que requirieron de cirugía periapical. El grupo experimentalfue tratado con una aplicación intraoral de laser de GaAsAl de 810 nm, con una potencia de 100 Mw, con movimientos oscilatorios sobre la herida quirúrgica. En el grupo control, se llevó a cabo el mismo procedimiento, sin la activación del láser terapéutico. Se registraron dolor postoperatorio, inflamación y medicación de rescate. El grupo experimental mostró una disminución en la intensidad del dolor posterior a la cirugía periapical en comparacióncon el grupo control (p<0.05). No se encontró diferencia estadísticamente significativa entre los grupos entérminos de inflamación. Seis pacientes del grupo control requirieron medicación de rescate. El uso de LTBNE en el manejo postoperatorio de pacientes sometidos a cirugíaperiapical, usando el protocolo del presente estudio redujo el dolor postoperatorio...

Distribution of genotypes of Porphyromonas gingivalis in type 2 diabetic patients with periodontitis in Mexico.

OBJECTIVE: To determine and compare the distribution of Porphyromonas gingivalis fimA genotypes in type 2 diabetes mellitus (T2DM) patients affected by periodontitis, using non-diabetic subjects with and without periodontitis as control groups. MATERIAL AND METHODS: This study involved 75 subjects divided into three groups of 25 subjects each: Group 1 (non-T2DM without periodontitis), Group 2 (non-T2DM with periodontitis) and Group 3 (T2DM with periodontitis). The outcome variable was periodontitis, and explanatory variables were age, sex, T2DM and specific P. gingivalis fimA genotypes. RESULTS: In non-T2DM subjects with healthy periodontal tissues, type I fimA was the most frequently detected individually (40%) or in combinations (40%). In non-T2DM subjects with periodontitis, the most frequently detected type was Ib individually (20%) or in combinations (36%). In T2DM patients with periodontitis, the most frequently detected types were types I (20%) and III (20%), but there was no statistical difference (p>0.05) with non-T2DM periodontitis subjects. CONCLUSIONS: Type I genotype was more frequently detected in periodontally healthy sites from non-T2DM subjects than in periodontitis sites from either subjects with or without T2DM. However, in sites affected by periodontitis from T2DM subjects the predominating types were I and III, which are less virulent strains of P. gingivalis.

Oral rehabilitation under dental general anesthesia, conscious sedation, and conventional techniques in patients affected by cerebral palsy.

The purpose of this report is to find the use of different alternatives for dental treatment, from general anesthesia to conventional techniques, in patients affected by cerebral palsy (CP) in a dental school setting. The sample was divided into two groups: (1) children, and (2) adolescents and young adults; 38 patients (20 female and 18 male) with diagnostic of CP were included. Risks and benefits of conscious sedation and general anesthesia were written into a consent form and these were discussed with parents or guardians of each affected patient. The mean age was 7.14+/-2.2 years for children's group and 18.5+/-3.06 years for adolescent and young adult group. Most children (77.3%) were classified as ASA II with a level of behavior I-II according to Frankl's scale and these patients were treated under general anesthesia (GA). For patients that were classified as of positive behavior with little necessity of dental procedures, independent of the medically compromised level, dental treatment was done with conventional techniques or with conscious sedation. Dental frequency procedures were as follows: composites, dental prophylaxis, and dental extractions in children; in adolescents and adults, important to point out is that in anterior teeth and molars endodontic treatment, and surgical procedures increased in frequency. The mixture sevoflurane-propofol worked well during pre-, peri-, and post-operative procedures. During the discharge process, most patients needed a recovery of 20-40 minutes after which they were awake and oriented, breathing comfortably with stable vital signs. It was concluded that GA with sevoflurane-propofol and conscious sedation are an excellent tool to provide dental treatment in CP patients in a dental school setting without most of the major postoperative complications, such as nausea and vomiting.