Biomedical subjects

C Canalda-Sahli

Publications and source records attributed to C Canalda-Sahli.

10 recordsLinked to original sources

PubMed1998

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.

Absorption↗

PubMed1998

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.

Alloys↗

PubMed1997

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.

Carbon↗

PubMed1997

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.

Alloys↗

PubMed1996

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.

Alloys↗

PubMed1996

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.

Dental Instruments↗

PubMed1996

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.

Alloys↗

PubMed1994

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.

Evaluation Studies as Topic↗

PubMed1992

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.

Administration, Topical↗

PubMed1989

[Efficacy of the glass bead sterilizer on endodontic instruments].

The time taken to achieve the sterilization of K files impregnated in a Bacillus subtilis culture was evaluated, placing the files in a glass bead sterilizer. The minimum time needed was 20 seconds at 240 degrees C and the previous cleaning of the file with a sterile wipe impregnated by alcohol reduced this time to 15 seconds.

Bacillus subtilis↗