Softening of the gutta-percha by laser irradiation and its thermal impact in the canal obturation

1998 ◽  
Author(s):  
Roberto Ortega-Martı́nez ◽  
Antonio Rodrı́guez-Rosales ◽  
Manuel Calzada-Nova ◽  
Antonio Copin-Tovar
Keyword(s):  
Laser Irradiation ◽  
Thermal Impact ◽  
Gutta Percha

scholarly journals Effect of diode laser irradiation on the apical sealing of MTA retrofillings

2006 ◽  
Vol 20 (3) ◽  
pp. 231-234 ◽  
Author(s):  
Eliana Barbosa de Souza ◽  
Crystiane Venditti Gomes de Amorim ◽  
José Luiz Lage Marques
Keyword(s):  
Laser Irradiation ◽  
Diode Laser ◽  
In Vitro Study ◽  
Apical Surface ◽  
Human Teeth ◽  
Root Canals ◽  
Gutta Percha ◽  
Group 2 ◽  
Student’S T

Apical sealing is essential for the success of paraendodontic surgery, so any procedure that may favor an adequate sealing of the apical remainder should be performed. The purpose of this study was to evaluate the influence of diode laser irradiation on the apical sealing of root-end cavities with MTA retrofillings. Root canals in twenty extracted human teeth were shaped with K-files and filled with gutta-percha. The apexes were cut off and root-end preparations were performed. The roots were divided randomly in 2 groups. Group 1 (ten specimens) was retrofilled with MTA. Group 2 was irradiated with diode laser, with 1 W for 20 seconds, on the apical surface and root end cavity before retrofilling with MTA. The specimens had their external surfaces impermeabilized with cyanoacrylate, except for the apical surface, and were then immersed in 1% rhodamine B dye for 72 h and placed in plaster stone. After that, the specimens were submitted to longitudinal abrasion until half of the root remained. The linear dye leakage was observed in these mid-roots between the root canal wall and retrofilling. The linear dye leakage was measured with Image Lab software, and the results were statistically analyzed with Student's t test. There were no statistically significant differences between the two groups (p > 0.05). The diode laser irradiation did not improve the apical sealing of MTA retrofillings under the conditions of this in vitro study.

Reduction of collateral thermal impact of diode laser irradiation on soft tissue due to modified application parameters

2011 ◽  
Vol 27 (5) ◽  
pp. 917-921 ◽  
Author(s):  
F. Beer ◽  
W. Körpert ◽  
H. Passow ◽  
A. Steidler ◽  
A. Meinl ◽  
...  
Keyword(s):  
Soft Tissue ◽  
Laser Irradiation ◽  
Diode Laser ◽  
Thermal Impact

scholarly journals Using erbium-doped yttrium aluminum garnet laser irradiation in different energy output levels versus ultrasonic in removal of root canal filling materials in endodontic retreatment

2017 ◽  
Vol 11 (03) ◽  
pp. 281-286 ◽  
Author(s):  
Mehmet Omer Gorduysus ◽  
Hanin Al-Rubai ◽  
Basheer Salman ◽  
Deena Al Saady ◽  
Hiba Al-Dagistani ◽  
...  
Keyword(s):  
Laser Irradiation ◽  
Root Canal ◽  
Yttrium Aluminum Garnet ◽  
Er:Yag Laser ◽  
Gutta Percha ◽  
Group I ◽  
Significant Difference ◽  
Erbium Doped ◽  
Yttrium Aluminum ◽  
Endodontic Retreatment

ABSTRACT Objectives: The objective of this study was to evaluate the efficacy of erbium-doped yttrium aluminum garnet (Er:YAG) laser irradiation in different energy outputs versus ultrasonic in gutta-percha removal during the endodontic retreatment. Materials and Methods: A total of 21 extracted human lower premolars were divided into three groups (n = 7). Following the standardized preparation of the root canals with Wave One Rotary system and obturation with gutta-percha: Group I was treated with ultrasonic, Group II by Er:YAG laser with 40 mJ/Pulse, and Group III by Er:YAG laser with 50 mJ/Pulse for the removal of gutta-percha from the canals. Two extra teeth were treated by Er:YAG laser with 135 mJ/Pulse as control group. For all groups, time for gutta-percha removal was recorded. Samples were then splited into two halves and tested by scanning electron microscope and stereomicroscopic evaluation under different magnification power to observe the efficacy of each method used in the removal of gutta-percha. Results: Statistical analysis of Kruskal–Wallis suggested that there are significant difference between the groups in relation to removal time (P < 0.05) and 2 × 2 Mann–Whitney U-test among the groups revealed that there is no significant difference between 40 and 50 mJ laser outputs (P > 0.05), but ultrasonic versus 40 and/or 50 mJ laser outputs were significantly different (P < 0.05). Conclusions: Er:YAG laser beam was not so efficient when compared to ultrasonic to reach the deeper parts of the canals as it was asserted, thermal side effects and burning damages were observed on the root canal dentinal walls. Moreover, the delivery system was not flexible enough to compensate the curvature of the canal system even though we used more straight canals as the sample ones as well as more time-consuming than the ultrasonic and more clinical time, rendering it to be less efficient in the removal of the obturation material during endodontic retreatment procedures.

scholarly journals Apical microleakage and SEM analysis of dentin surface after 980 nm diode laser irradiation

2011 ◽  
Vol 22 (5) ◽  
pp. 382-387 ◽  
Author(s):  
Maria Isabel Anastácio Faria ◽  
Aline Evangelista Souza-Gabriel ◽  
Edson Alfredo ◽  
Danielle Cristine Furtado Messias ◽  
Yara Teresinha Correa Silva-Sousa
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Laser Irradiation ◽  
Diode Laser ◽  
Laser Power ◽  
Sem Analysis ◽  
Gutta Percha ◽  
Ah Plus ◽  
Apical Leakage ◽  
Scanning Electron

This study evaluated the effect of 980-nm diode laser on apical microleakage and intraradicular dentin morphology. Roots of 110 mandibular incisors were used in the study: 92 for microleakage test and 18 for scanning electron microscopy (SEM). Roots were randomly assigned to 3 groups according to the irrigating solution (water, NaOCl and NaOCl/EDTA) and were divided into 3 subgroups according to the laser irradiation protocol (without irradiation, irradiated at 1.5 W and irradiated at 3.0 W). Two specimens of each subgroup were prepared for SEM. The remaining roots were filled with AH Plus and gutta-percha. Apical leakage was assessed by ink penetration and data were analyzed statistically by ANOVA and Tukey-Krammer test (α=0.05). SEM analysis showed intensification of changes with increase of laser power as well as variations according to the irrigating solution. Modified smear layer was observed in specimens treated with water and irradiated with laser. Roots irrigated with NaOCl/EDTA had lower levels of infiltration (0.17 ± 0.18 mm) differing significantly (p<0.05) from those of roots irrigated with water (0.34 ± 0.30 mm), but similar (p>0.05) to those irrigated with NaOCl (0.28 ± 0.29 mm). Non-irradiated roots had lower levels of infiltration (0.10 ± 0.14 mm), differing (p<0.05) from those irradiated at 1.5 W (0.32 ± 0.22 mm) and 3.0 W (0.37 ± 0.32 mm). The 980 nm diode laser modified dentin morphology and increased apical microleakage.

Chronic Laser Exposure Effects on Rabbit Retina

1972 ◽  
Vol 30 ◽  
pp. 54-55
Author(s):  
Burton B. Silver ◽  
Theodore Lawwill
Keyword(s):  
Laser Irradiation ◽  
Laser Light ◽  
Broad Band ◽  
Argon Laser ◽  
Atropine Sulfate ◽  
Ultrastructural Changes ◽  
Laser Exposure ◽  
Rabbit Retina ◽  
Histological Changes ◽  
Threshold Doses

Dutch-belted 1 to 2.5 kg anesthetized rabbits were exposed to either xenon or argon laser light administered in a broad band, designed to cover large areas of the retina. For laser exposure, the pupil was dilated with atropine sulfate 1% and pheny lephrine 10%. All of the laser generated power was within a band centered at 5145.0 Anstroms. Established threshold for 4 hour exposures to laser irradiation are in the order of 25-35 microwatts/cm2. Animals examined for ultrastructural changes received 4 hour threshold doses. These animals exhibited ERG, opthalmascopic, and histological changes consistent with threshold damage.One month following exposure the rabbits were killed with pentobarbitol. The eyes were immediately enucleated and dissected while bathed in 3% phosphate buffered gluteraldehyde.

Microstructural changes of Aluminum Nitride after laser irradiation and electroless copper deposition

1994 ◽  
Vol 52 ◽  
pp. 636-637
Author(s):  
S. Cao ◽  
A. J. Pedraza ◽  
L. F. Allard
Keyword(s):  
Aluminum Nitride ◽  
Laser Irradiation ◽  
Electroless Deposition ◽  
Thermal Evaporation ◽  
Surface Region ◽  
Near Surface ◽  
Laser Patterning ◽  
Electroless Copper ◽  
Excimer Laser Irradiation ◽  
Laser Effect

Excimer-laser irradiation strongly modifies the near-surface region of aluminum nitride (AIN) substrates. The surface acquires a distinctive metallic appearance and the electrical resistivity of the near-surface region drastically decreases after laser irradiation. These results indicate that Al forms at the surface as a result of the decomposition of the Al (which has been confirmed by XPS). A computer model that incorporates two opposing phenomena, decomposition of the AIN that leaves a metallic Al film on the surface, and thermal evaporation of the Al, demonstrated that saturation of film thickness and, hence, of electrical resistance is reached when the rate of Al evaporation equals the rate of AIN decomposition. In an electroless copper bath, Cu is only deposited in laser-irradiated areas. This laser effect has been designated laser activation for electroless deposition. Laser activation eliminates the need of seeding for nucleating the initial layer of electroless Cu. Thus, AIN metallization can be achieved by laser patterning followed by electroless deposition.

Studies on the mechanism of printing film-coated tablets containing titanium dioxide in the film by using UV laser irradiation

2009 ◽  
Vol 00 (00) ◽  
pp. 090915102728058-8
Author(s):  
Yoshiteru Kato ◽  
Yasuhiko Nakashima ◽  
Naoki Shino ◽  
Koichi Sasaki ◽  
Akihiro Hosokawa ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Laser Irradiation ◽  
Uv Laser

Modification of structural and transport properties in epitaxial YBa2CU3Ox films by pulsed laser irradiation

1993 ◽  
Vol 3 (12) ◽  
pp. 2173-2188
Author(s):  
N. G. Chechenin ◽  
A. V. Chernysh ◽  
V. V. Korneev ◽  
E. V. Monakhov ◽  
B. V. Seleznev
Keyword(s):  
Transport Properties ◽  
Laser Irradiation ◽  
Pulsed Laser ◽  
Pulsed Laser Irradiation
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