Estudio comparativo de la preparación de los conductos radiculares con diversos sistemas de instrumentación mecánico-rotatoria / No disponible

Objetivo: el objetivo de este estudio fue evaluar la deformación longitudinal en conductos curvos artificiales instrumentados con las limas mecánico-rotatorias de niquel titanio HERO Shaper y RaCe, determinar el calibre y conicidad de la lima maestra apical, así como la primera lima que inició la deformación. Material y métodos: Un total de 20 conductos curvos artificiales fueron distribuidos aleatoriamente en dos grupos de 10 cada uno. Se prepararon los conductos utilizando la técnica crown-down. Se superpusieron las imágenes obtenidas mediante observación estéreo-microscópica de un mismo conducto radicular antes y después de su instrumentación. Se mantuvieron la posición y los aumentos en las observaciones realizadas con todas las muestras utilizadas en este estudio. Los datos obtenidos fueron analizados utilizando el test de Kruskal Wallis y el test de la U de Mann Whitney. Resultados: Se prepararon los cubiletes del grupo RaCe con una secuencia menor de limas. La preparación del tercio coronal, con ambos sistemas, fue homogénea amentando la deformación en el tercio medio y parte del tercio apical. La deformación en la preparación de los últimos dos milímetros fue menor con la límas RaCe que con las de HERO Shaper. La primera lima que inició la deformación con RaCe fue de igual conicidad y de calibre mayor que HERO Shaper. Conclusiones: Bajo las condiciones de este estudio RaCe mantuvo mejor la curvatura original del conducto artificial que HERO Shaper (AU)

Objective: The aim of this study was to evaluate the longitudinal transportation of artifically curved canals instrumetne with two Rotary Niti systems (HERO Shaper and RaCe), as well as to determine the size and the taper of the apical master file, and the size and taper of the first file which started the transportation. Methodology: 20 artificially curved canals ( plastic blocks) were prepared, and divided into 2 groups of 10: group HS (prepared with HERO files) and group RC (prepared with RaCe files). The canals were instrumented according to the crown-down technique. Pre-op and post-op pictures of the same canals were superposed for a stereoscopic observation. All samples of this study were examined under the same conditions: position and image magnification. The results were analyzed according to the Kruskel Wallis and Mant Whitney LL test. Results: The plastic blocks of the RaCe group were instrumented in a shorter sequence. No difference was observed in the preparation of the coronal third between the systems. However the transportation increased in the middle and apical thirds. The first RaCe file that started trasportation was of the same taper but of a larger diameter than the HERO Shaper. Conclusions: According to our study, RaCe respected the original curvature of the artificial canal better than HERO Shaper (AU)

Estudio con microscopio electrónico del barrido del smear layer residual después de la instrumentación de conductos radiculares con distintos instrumentos rotatorios (AU) / No disponible

Objetivo: Se evaluó comparativamente la presencia de smear layer residual tras la instrumentación de conductos con dos sistemas de instrumentación diferentes; uno con apoyos radiales: ProFile y otro sin ellos: RaCe. Metodología: Se seleccionaron 15 conductos de molares extraídos y se distribuyeron aleatoriamente en tres grupos de 5 cada uno (grupo PP: motor eléctrico de una velocidad de 300 r.p.m. y un torque dinámico AP-10. En los tres grupos, la irrigación entre cada instrumento se realizó alternando 2 ml de NaOCI (5,25%) y 2 ml de ác. Cítrico 820%9. La limpieza de las paredes de los conductos se estudió con Microscopia electrónica de barrido utilizando 5 categorías para cuantificar la cantidad de smear layer a 1000 aumentos. El análisis estadístico de los resultados se realizó con el test de Kruskal-Walls y la U de Mann-Whitney (...) (AU)

Aim: Compare the smear layer left on canal walls after rool cannal instrumentation with two different systems: one with radial lands - Profile and another without radial lands - RaCe. Methodology: 15 molar root canals were divided into 3 groups of 5. Group PF; Profile, group Rc: RaCe, group RCSA: RaCe and S-Apex. there were all run in a 1:18 WH reducing contra-angle on an electric motor, at a 300 rpm speed and AP-10 dynamic lorque. For all groups, irrigation was performed alternating 2 ml NaOCU (at 5,25%) and 2 ml citric acid (at 20%) after each instrument. Cleaning of canal walls was observed under SEM at a 1000x magnification, using a 1 to 5 scale to quantify the amount of semera layer left. Satitiscial analysis of the results was made using the Kruskal Walls and Mann-Whitney U test (...)(AU)

Procesos endoperiodontales. II. Lesiones endoperiodontales / No disponible

Analiza una clasificación clínica de las lesiones endoperiodontales, la historia clínica para alcanzar un diagnóstico así como las opiniones terapéuticas de las mismas (AU)

Analysis of clinical classification for the endoperiodontal lesions, of the clinical history required to achieve a diagnosis and of their therapeutic options (AU)

Procesos endoperiodontales. I. Bases biológicas e interrelaciones / Endoperiodontal pathology. I. Biologic basis

Las relaciones endoperiodontales siguen siendo un tema de actualidad sujeto a controversia. Se analizan sus características macro y microscópicas así como la interrelación entre la patología pulpar y periodontal

Nowadays, the endoperiodontal relationships are still a present time theme that is subject to controversy. Their macro and microscopic features are analysed as well as the relationship between the pulp pathology and the periodontal disease

The effect of sterilization on bending and torsional properties of K-files manufactured with different metallic alloys.

The purpose of this study was to assess the effect of dry-heat or autoclave sterilization on the resistance to fracture in torque and angular deflection and the resistance to bending of K-type files made of nickel-titanium (Nitiflex, Naviflex), titanium (Microtitane) or stainless steel (Flexofile, Flex-R). Ten K-type files of each sort, from size 25 to 40, were tested, according to ANSI/ADA specification 28 (1988) and ISO specification 3630 (1992). Sterilization with dry heat and autoclave slightly decreased the flexibility of files made of stainless steel and nickel-titanium for most of the sizes, although the values obtained satisfied ISO specifications. The files made of titanium showed an increased flexibility after sterilization with autoclave (sizes 30 and 35) and dry heat (sizes 30, 35 and 40). Resistance to fracture varied amongst the five groups of files tested as follows: it decreased in some sizes of stainless-steel instruments, decreased in all sizes of titanium files assessed by the torsional moment, and either increased or decreased in some sizes of nickel-titanium files. All files tested, however, satisfied relevant standards for angular deflection after being subjected to sterilization with an autoclave or dry heat.

Absorbency properties of different brands of standardized endodontic paper points.

A comparative study of the absorbency properties of different endodontic paper points has been conducted. Twenty standardized absorbent paper points, size 30, from 13 bands (Dentaline, Zipperer, Kerr, Diadent, Roeko novo, Roeko color, Maillefer, P.D., Schein, Spectrapoint, Proclinic, Euronda, and Alpro) of 12 manufacturers were tested. Each dry paper point was weighted using an electronic laboratory balance. A length of 16 mm from the tip was then lowered in distilled water for 5 s, the paper point was weighted again, and the difference between both measurements was taken as the value of the fluid absorbed. Diadent, Kerr, and Dentalite showed significantly higher absorbencies (p < 0.05) than standardized paper points of the remaining brands. The study demonstrates a wide variation in the absorbency properties of this dental accessory.

A comparison of molar root canal preparations using six instruments and instrumentation techniques.

Six different instruments (Flexofile, Canal Master U, Heliapical, Flexogate, Ultraflex, and Lightspeed) were evaluated in 240 mesial canals of extracted mandibular molars (40 canals per instrument type). After instrumentation, the roots were cross-sectioned 2, 5, and 9 mm from the apex. The cross sections were evaluated to determine the quality of canal preparation (round, oval, irregular). The best results were obtained with nickel-titanium, a short cutting blade and a rotary rather than a filing motion. The Canal Master U, Flexogate, and Lightspeed instruments had significantly more round canals than the Flexofile, Heliapical and Ultraflex instruments at all levels. The Lightspeed had the largest number of round canals at all levels. Instrumentation time was also recorded. The Canal Master U and Flexogate were significantly slower than the Flexofile, heliapical, Ultraflex, and Lightspeed instruments. There were no statistically significant differences within the faster group.

Apical sealing using two thermoplasticized gutta-percha techniques compared with lateral condensation.

This study was conducted to compare the apical sealing capacity of three filling techniques, a multiphase gutta-percha obturation technique, JS Quickfill, and lateral gutta-percha condensation. A four-stage stepback preparation was executed with circumferential filing in a total of 70 recently extracted permanent maxillary incisors and canines. Three experimental groups (20 teeth in each group) and two control groups (5 teeth in each group) were formed at random. Each experimental group was obturated with a different technique. The positive control group was not obturated. In the negative control group, the whole root was covered with two full nail varnish layers. Teeth were immersed in India ink for 48 h, demineralized, cleared with methyl salicylate, and examined with a stereomicroscope. None of the specimens obturated with the multiphase gutta-percha obturation system showed any penetration of India ink beyond the end of the preparation. In the groups of teeth obturated by JS Quickfill or lateral gutta-percha condensation, leakage was detected in one specimen from each group. No statistically significant differences were seen among groups. We conclude that the newer thermoplasticized filling techniques can be used successfully to obturate root canals in large, straight roots.

Cutting efficiency of K-files manufactured with different metallic alloys.

The aim of this study was to compare, in vitro, the machining efficiency of different triangular cross-section K-files made of nickel titanium (Nitiflex, Naviflex), titanium (Microtitane), and stainless steel (Flexofile, Flex-R). Ten instruments of each K-file from size 25 to 40 were tested. The cutting efficiency was assessed in a linear motion using an indentation caliper to measure the depth of grooves. The load applied (in grams) was equal to the ISO file size. Each file was allowed to do 100 back-and-forward movements. Files made of stainless steel were the most effective, in particular Flexofile. There were statistically significant differences between Flexofile and Flex-R in all sizes. In the group of nickel titanium instruments, Nitiflex was significantly more efficient than Naviflex in all sizes. The machining ability of titanium files was higher than that of Naviflex but lower than that of Nitiflex and stainless steel files.

Torsional and bending properties of stainless steel and nickel titanium Canal Master U and Flexogate instruments.

The purpose of this study was to assess and to compare the torsional and bending properties of the Canal Master U (CMU) and Flexogate instruments made of stainless steel and nickel titanium. The bending moment, the torsional moment and angular deflection were measured according to ANSI/ADA specification number 28 and ISO reference number 3630. Ten instruments of each size, sizes 25 to 40 were used for each test. Nickel titanium instruments were significantly more flexible than stainless steel files. With regard to the torsional moment, values obtained were below the standards in all sizes except stainless steel CMU sizes 25, 35 and 40, and nickel titanium CMU size 25. Nickel titanium instrument also showed the highest angular deflection values. There were statistically significant differences between nickel titanium files and stainless steel Flexogates and between stainless steel Flexogates and stainless steel CMU. Based on these findings, the use of nickel titanium CMU and Flexogates is encouraged. Given the perceived advantages of both CMU and Flexogate instruments over conventional files for canal preparation, it would appear desirable to have the torque resistance of these instruments improved.

A comparison of bending and torsional properties of K-files manufactured with different metallic alloys.

The purpose of this study was to compare bending (bending moment) and resistance to fracture by twisting (torsional moment and angular deflection) of triangular cross-section K-files made of either nickel titanium (Nitiflex, Naviflex), titanium (Microtitane) or stainless steel (Flexofile, Flex-R). A total of 200 files were tested, 10 instruments for each type from size 25 to 40, according to ANSI/ADA specification no. 28 and ISO reference no. 3630. Files made of nickel titanium, especially Nitiflex, were the most flexible. Stainless steel instruments presented a higher bending moment than files made of nickel titanium and titanium, particularly Flex-R sizes 35 and 40. With regard to resistance to fracture, measured by angular deflection at the failure point, Flexofile followed by Flex-R were the most resistant to fracture and Nitiflex were the least resistant. Differences in angular deflection among file groups were greater than those for torsional moment. Thus, it seems that angular deflection is a more specific measurement for assessing resistance to fracture by twisting.

A comparison of molar root canal preparations using Flexofile, Canal Master U, and Heliapical Instruments.

There are many instruments and techniques for cleaning and shaping the root canal system, but none achieves the ideal preparation, especially in curved canals. This study compared the step-back technique, using Heliapical and Flexofiles, with the Canal Master technique, using Canal Master U instruments. The Bramante method evaluated and compared the results. Final analysis showed that root canals prepared with Canal Master U instruments and technique were significantly rounder, and had less transportation than those prepared by the Heliapical and Flexofiles using the step-back technique.

The apical seal of root canal sealing cements using a radionuclide detection technique.

The aim of this study was to evaluate the apical seal obtained with various root canal sealing cements using a new method based on the use of a radionuclide and an external detection technique. A total of 150 maxillary incisors and canines, which had been kept in saline solution, were used. The root canals were instrumented with a stepback technique and circumferential filing. Six experimental groups and two control groups were randomly formed. Each experimental group was obturated by a lateral condensation technique with gutta-percha points and a different sealing cement (two based on zinc oxide-eugenol cement, two based on resins and two on calcium hydroxide); the positive control used gutta-percha without sealing cement, while in the negative control the apex was covered with nail varnish, leaving the root canal empty. The apical leakage was measured using an external detection technique after submerging the root apices in a solution containing the radioisotope metastable 99Tc. No leakage was observed in the negative control group. There was a large difference between the leakage observed in the positive control group and the experimental groups. The best seal was obtained using Sealapex cement, which differed significantly from AH26, Tubli-Seal and Diaket; there was no significant difference between the latter. The poorest results were obtained with Endomethasone and CRCS; there was a significant difference between these and the previous three sealing cements.

[Radioactive isotope evaluation of apical seal of two types of thermoplasticized gutta-percha at high and low temperature]. / Evaluation à l'aide d'isotopes radio-actifs de l'étanchéité apicale de deux types de gutta-percha thermoplastifiée à haute et basse température.

The aim of this study was to evaluate the apical seal obtained using root canal filling techniques based on low and high temperature thermoplasticized gutta-percha, comparing them with the lateral condensation technique. The roots of thirty permanent upper canines and incisors were used, they were instrumented and obturated using each of the above techniques. The apical leakage was measured using a radioactive isotope and an external detection technique. No significant difference was found in the apical seal obtained by the three techniques.