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1.
This study evaluated (1) the micromorphology by scanning electron microscopy (SEM) and (2) the adhesive performance by microtensile
bond strength (μTBS) of diamond bur-treated dentin compared to Er:YAG laser-treated dentin of human primary teeth. (1) For
qualitative SEM evaluation, dentin of 18 second primary molars (n = 3/method) was treated with either diamond bur as a control (group 1a: 40 μm diamond bur only (clinical situation); group
1b: grinding + 40 μm diamond bur) or with Er:YAG laser (group 2a (clinical situation, manufacturer’s settings): 200 mJ/25 Hz
(5 W) + 100 mJ/35 Hz (3.5 W) laser only; group 2b (experimental setting "high"): grinding + 400 mJ/20 Hz (8 W); group 2c (manufacturer’s
setting "finishing"): grinding + 100 mJ/35 Hz (3.5 W); group 2d (experimental setting "low"): grinding + 50 mJ/35 Hz (1.75 W)).
(2) For evaluation of adhesive performance, 64 second primary molars were divided into four groups and treated as described
for group 1b and groups 2b/c/d (n = 16/method), and μTBS of Clearfil SE/Clearfil Majesty Esthetic to dentin was measured. The SEM micrographs were qualitatively
analyzed. The μTBS values were compared with a Kruskal–Wallis test. The significance level was set at α = 0.05. SEM micrographs
showed the typical micromorphologies with a smear layer for the diamond bur groups and open dentin tubules for all laser-treated
groups. However, in group 2d, the laser beam had insufficiently irradiated the dentin area, rendering the underlying ground
surface partly visible. There were no statistically significant differences between μTBS values of the four groups (p = 0.394). This suggests that Er:YAG laser treatment of dentin of primary molars provides bond strengths similar to those
obtained following diamond bur treatment. 相似文献
2.
The purpose of this study was to evaluate vibrations induced by an erbium:yttrium–aluminum–garnet (Er:YAG) laser in the non-contact
mode and compare the vibrations with different pulse durations and energy parameters. The experiment was conducted on an extracted
tooth built up in silicone impression material. The vibrations were measured by piezoelectric accelerometer for a super-short
pulse (SSP), a very short pulse (VSP), and a short pulse (SP) at a frequency of 5 Hz for 1 s. For VSP and SP, the energy parameters
tested were 200 mJ, 300 mJ, and 400 mJ. Measurements were performed 15 times for each individual irradiation energy level.
The highest values of vibrations were measured for SP (0.160 ± 0.04 m/s2), and the lowest were measured for VSP mode at the energy parameter 200 mJ (0.05 ± 0.02 m/s2). There was a statistically significant (P < 0.01) difference between the various laser pulse modes (SSP, VSP, SP) at different energy parameters. At energy levels
of 300 mJ and 400 mJ, the least amount of vibration during cavity preparations with the non-contact Er:YAG laser was produced
by SSP mode. 相似文献
3.
OBJECTIVE: The aim of this study was to observe and evaluate the micro-morphology of enamel and dentin surfaces after Er:YAG laser preparation and conditioning. BACKGROUND DATA: Information regarding micro-morphologic changes of tooth substance as a result of a change of Er:YAG laser parameters for cavity preparation is limited. METHODS: Human enamel and dentin surfaces were irradiated with an Er:YAG laser with the following parameters : (1) energy output: 200 mJ, 250 mJ, 300 mJ, 350 mJ, and 400 mJ; (2) repetition rate: 5 Hz and 10 Hz; (3) pulse duration: 100 mus/VSP (very short pulse); (4) 5 and 10 passes over the surface at a distance of 7 mm, speed: 4 mm/s using a non-contact delivery tip; (5) water cooling: 5 mL/min. The hand piece was fixed in a power driven x-y moving table. Subsequently, half of the samples were laser-conditioned at 100 mJ, 10 Hz, 250 mus/SP (short pulse) for enamel, and 80 mJ, 10 Hz, SP for dentin at a distance of 10 mm. Surface morphology and surface alterations were evaluated using scanning electron microscopy (SEM). RESULTS AND CONCLUSION: SEM evaluation showed the characteristics of Er:YAG-lased enamel and dentin surfaces: irregular enamel surfaces with typical keyhole shaped prisms and rods, and protrusion of dentinal tubules with a cuff-like appearance. Laser conditioning rounded off the sharp edges on the enamel irregularities and dentin surface structures. First signs of vitrification were seen at 250 mJ for enamel samples and 300 mJ for dentin samples. Increase of the pulse repetition rate from 5 Hz to 10 Hz did not result in changes of surface morphology. Laser conditioning did not result in additional vitrification. 相似文献
4.
Marta Maria Martins Giamatei Contente Fabrício Augusto de Lima Rodrigo Galo Jesus Djalma Pécora Luciano Bachmann Regina Guenka Palma-Dibb Maria Cristina Borsatto 《Lasers in medical science》2012,27(1):1-5
This study aimed to assess in vitro thermal alterations taking place during the Er:YAG laser cavity preparation of primary
tooth enamel at different energies and pulse repetition rates. Forty healthy human primary molars were bisected in a mesio-distal
direction, thus providing 80 fragments. Two small orifices were made on the dentin surface to which type K thermocouples were
attached. The fragments were individually fixed with wax in a cylindrical Plexiglass? abutment and randomly assigned to eight
groups, according to the laser parameters (n = 10): G1 – 250 mJ/ 3 Hz, G2 – 250 mJ/ 4 Hz, G3 – 250 mJ/ 6 Hz, G4 – 250 mJ/10 Hz, G5 – 250 mJ/ 15 Hz, G6 – 300 mJ/ 3 Hz,
G7 – 300 mJ/ 4 Hz and G8 – 300 mJ/ 6 Hz. An area of 4 mm2 was delimited. Cavities were done (2 mm long × 2 mm wide × 1 mm thick) using non-contact (12 mm) and focused mode. Temperature
values were registered from the start of laser irradiation until the end of cavity preparation. Data were analyzed by one-way
ANOVA and Tukey test (p ≤ 0.05). Groups G1, G2, G6, and G7 were statistically similar and furnished the lowest mean values of temperature rise. The
set 250 mJ/10 and 15 Hz yielded the highest temperature values. The sets 250 and 300 mJ and 6 Hz provided temperatures with
mean values below the acceptable critical value, suggesting that these parameters ablate the primary tooth enamel. Moreover,
the temperature elevation was directly related to the increase in the employed pulse repetition rates. In addition, there
was no direct correlation between temperature rise and energy density. Therefore, it is important to use a lower pulse frequency,
such as 300 mJ and 6 Hz, during cavity preparation in pediatric patients. 相似文献
5.
Ricardo Scarparo Navarro Sheila Gouw-Soares Alessandra Cassoni Patricia Haypek Denise Maria Zezell Carlos de Paula Eduardo 《Lasers in medical science》2010,25(6):881-889
The objective of this study was to evaluate the influence of various pulse widths with different energy parameters of erbium:yttrium–aluminum–garnet
(Er:YAG) laser (2.94 μm) on the morphology and microleakage of cavities restored with composite resin. Identically sized class
V cavities were prepared on the buccal surfaces of 54 bovine teeth by high-speed drill (n = 6, control, group 1) and prepared by Er:YAG laser (Fidelis 320A, Fotona, Slovenia) with irradiation parameters of 350 mJ/
4 Hz or 400 mJ/2 Hz and pulse width: group 2, very short pulse (VSP); group 3, short pulse (SP); group 4, long pulse (LP);
group 5, very long pulse (VLP). All cavities were filled with composite resin (Z-250-3 M), stored at 37°C in distilled water,
polished after 24 h, and thermally stressed (700 cycles/5–55°C). The teeth were impermeabilized, immersed in 50% silver nitrate
solution for 8 h, sectioned longitudinally, and exposed to Photoflood light for 10 min to reveal the stain. The leakage was
evaluated under stereomicroscope by three different examiners, in a double-blind fashion, and scored (0–3). The results were
analyzed by Kruskal–Wallis test (P > 0.05) and showed that there was no significant differences between the groups tested. Under scanning electron microscopy
(SEM) the morphology of the cavities prepared by laser showed irregular enamel margins and dentin internal walls, and a more
conservative pattern than that of conventional cavities. The different power settings and pulse widths of Er:YAG laser in
cavity preparation had no influence on microleakage of composite resin restorations. 相似文献
6.
We investigated the effects of different Er:YAG laser treatments on the surface roughness of base metal alloys. A total of
36 specimens were prepared of two base metal alloys (Wiron 99, Bellabond plus). The surfaces of the specimens were standardized
by gradual wet grinding with 320-, 600-, 800- and 1,000-grit silicon carbide paper for 10 s each on a grinding machine at
300 rpm. Specimens of each alloy were randomly divided into six groups (n = 6) comprising a control group (group C), a group sandblasted with Al2O3 powder at 60 psi for 10 s through a nozzle at a distance of 10 mm (group S), and four Er:YAG laser (Fotona AT) treatment
groups. The laser treatment groups were as follows: 500 mJ, 10 Hz, 100 μs (group 500MSP); 500 mJ, 10 Hz, 300 μs (group 500SP);
400 mJ, 10 Hz, 100 μs (group 400MSP); and 400 mJ, 10 Hz, 300 μs (group 400SP). Surface roughness measurements (Ra) were performed
using a profilometer. The data were analysed by two-way ANOVA, and mean values were compared using Tukey’s HSD test (α = 0.05).
According to the two-way ANOVA results, the base metal alloys and interaction between base metal alloy and surface treatment
were not statistically significant different (p > 0.05), the surface treatments were significantly different (p < 0.0001). For the two base metal alloy groups, no significant differences were observed among the control, 400MSP, and 400SP
groups (p = 0.912), and these groups demonstrated the lowest Ra values. The highest Ra value was observed in group S (p < 0.05). Er:YAG laser treatment at 400 and 500 mJ/10 Hz is not an alternative method for surface roughening of base metal
alloys. 相似文献
7.
B. Bahrami N. Askari M. Tielemans D. Heysselaer L. Lamard A. Peremans C. Nyssen-Behets S. Nammour 《Lasers in medical science》2011,26(2):187-191
Several studies in the literature have previously shown that the bond strength of a composite bonded to dentin is almost equivalent
as when dentin is prepared by either bur or Er:YAG laser. The aim of this preliminary study is to assess the hypothesis that
dentin conditioning at low fluency by means of Er:YAG laser can improve the value of adhesion of composites resin to dentin.
Sixty surfaces of caries-free human third molars extracted for orthodontic purposes were randomly divided into five groups
of 12 teeth. The bur group was the control, prepared using bur, group L was prepared using Er:YAG 200 mJ, SSP (50 μs), 20 Hz,
15 seconds of sweeping, for groups L80, L100, L120, they were prepared first, with the same parameters of the group L 200,
and then they received a conditioning, which is, respectively, 15 s of irradiations at: 80 mJ (SSP, 10 Hz), 100 mJ (SSP, 10 Hz),
and 120 mJ (SSP, 10 Hz). All samples were restored in a single-component adhesive system: Xenon (DENTSPLY), and ceramX (DENTSPLY)
as the resin composite. The specimens were submitted to tensile bond strength test using a universal testing machine. Data
were submitted to statistical analysis using ANOVA coupled to a Tukey-Kramer test at the 95% level. The mean values in MPa
were 33.3 for group B, 36.73 for group L 200, 41.7 for group L80, 37.9 for group L100, and 39.1 for group L120. Our results
showed that dentin conditioning at a low fluency of 12.58 J/cm2 per pulse, with 80 mJ output energy and 50-μs pulse duration can significantly improve tensile bond strength of a composite
bonded to Er:YAG laser-prepared dentine. 相似文献
8.
Ramos AC Esteves-Oliveira M Arana-Chavez VE de Paula Eduardo C 《Lasers in medical science》2010,25(2):181-189
The aim of this in vitro study was to investigate the effect of erbium:yttrium–aluminum–garnet (Er:YAG) laser irradiation
on dentinal collagen by transmission electron microscopy and to analyze the resin–dentin interface by scanning electron microscopy.
A tensile bond strength test was also applied. Specimens from 69 sound human third molars were randomly divided into three
groups: control (no laser), and two irradiated groups, laser 250 (250 mJ/2 Hz) and laser 400 (400 mJ/4 Hz). Then, specimens
were restored with two adhesive systems, an etch-and-rinse or a self-etch system. Although ultrastructural examination showed
a modified surface in the irradiated dentin, there was no statistical difference in bond strength values between the laser
groups and controls (P < 0.05). In conclusion, the use of Er:YAG laser for ablating human dentin did not alter the main adhesion parameters when
compared with those obtained by conventional methods, thus reinforcing its use in restorative dentistry. 相似文献
9.
Gurgan S Kiremitci A Cakir FY Yazici E Gorucu J Gutknecht N 《Lasers in medical science》2009,24(1):117-122
The purpose of this study was to evaluate the dentin bond strength to resin composite following erbium:yttrium-aluminum-garnet
(Er:YAG) laser preparation using different adhesive systems. Seventy dentin specimens prepared from human molar teeth were
randomly assigned to seven groups of ten. The first five groups were prepared with an Er:YAG laser 2940 nm at the manufacturer’s
recommended settings and (1) acid etched, and etch-and-rinse adhesive Excite was applied; (2) Excite was applied; (3) two-step
self-etching adhesive AdheSE was applied; (4) laser etched (120 mJ/10 Hz), and Excite was applied; (5) laser etched, and AdheSE
was applied. The last two groups were added as controls (prepared with a diamond bur): (6) acid etched, and Excite was applied;
(7) AdheSE was applied. Nanohybrid composite cylinders 4 mm × 2 mm were bonded to the dentin surfaces. After the specimens
had been stored in distilled water and had undergone thermocycling, the shear bond strength was tested and the data were analyzed
statistically. The Duncan multiple comparison test showed that specimens prepared with a diamond bur and with acid and Excite
applied showed the highest mean bond strength (13.01 ± 2.09 MPa), followed by those prepared with Er:YAG and with AdheSE applied
(11.5 ± 3.59 MPa) and those prepared with a diamond bur and with AdheSE applied (10.75 ± 1.95 MPa), but there were no significant
differences among them (P > 0.05). Er:YAG-prepared specimens, with acid, Excite (3.28 ± 0.95 MPa) and specimens that were laser etched and with AdheSE
applied (3.37 ± 0.63 MPa) showed the lowest mean values for bond strength (P < 0.05). The results suggested that dentin surfaces prepared with Er:YAG laser may provide comparable composite resin bond
strengths depending on the adhesives used. 相似文献
10.
. The shear bond strength of composite resin on enamel and dentine was compared after acid-etch or irradiation by Er:YAG and
Nd:YAP lasers. Forty-eight extracted molars were selected. Dentine and enamel samples were prepared by buccal and lingual
surface sectioning to expose a plane enamel or dentine surface. Samples (n=12) were randomly assigned to eight groups. In groups 1 and 5, enamel and dentine surfaces were etched with a 37% phosphoric
acid solution. In groups 2 and 6, surfaces were irradiated by Er:YAG laser at an energy of 200 mJ and 4 Hz for enamel and
140 mJ and 4 Hz for dentine. In groups 3 and 7, irradiation was performed by Nd:YAP laser at 310 mJ and 10 Hz for enamel and
240 mJ and 10 Hz for dentine. Groups 4 and 8 served as controls. A cone of composite was bonded perpendicularly onto the prepared
surfaces using the Scotch Bond Multipurpose adhesive system. Each sample was then stored in physiological serum at 37°C for
one week and thermocycled. Shear bond strength was determined on a universal testing machine. Composite–enamel and composite–dentine
interfaces were examined by scanning electron microscopy and microanalysis. Shear bond strength was greater on dentine and
enamel after acid-etch than laser radiation. These treatments could be ranged in the following order: acid-etch, laser Er:YAG
and laser Nd:YAP. Differences between groups were significant for enamel, whereas no significant differences were found for
dentine between acid-etch and Er:YAG laser-irradiation (Kruskal–Wallis test). Thus, laser preparation did not improve bonding
to enamel and dentine.
Paper received 14 August 1998; accepted following revision 11 January 1999. 相似文献
11.
Eduardo dos Santos Leonetti José Augusto Rodrigues André Figueiredo Reis Ricardo Scarparo Navarro Ana Cecília Correa Aranha Alessandra Cassoni 《Lasers in medical science》2012,27(1):31-38
The objective of this study was to evaluate the influence of Er:YAG laser (λ = 2.94 μm) on microtensile bond strength (μTBS)
and superficial morphology of bovine dentin bleached with 16% carbamide peroxide. Forty bovine teeth blocks (7 × 3 × 3 mm3) were randomly assigned to four groups: G1- bleaching and Er:YAG irradiation with energy density of 25.56 J/cm2 (focused mode); G2 - bleaching; G3 - no-bleaching and Er:YAG irradiation (25.56 J/cm2); G4 - control, non-treated. G1 and G2 were bleached with 16% carbamide peroxide for 6 h during 21 days. Afterwards, all
blocks were abraded with 320 to 600-grit abrasive papers to obtain flat standardized dentin surfaces. G1 and G3 were Er:YAG
irradiated. Blocks were immediately restored with 4-mm-high composite resin (Adper Single Bond 2, Z-250-3 M/ESPE). After 24
h, the restored blocks (n = 9) were serially sectioned and trimmed to an hour-glass shape of approximately 1 mm2 at the bonded interface area, and tested in tension in a universal testing machine (1 mm/ min). Failure mode was determined
at a magnification of 100× using a stereomicroscope. One block of each group was selected for scanning electron microscope
(SEM) analysis. μTBS data was analyzed by two-way ANOVA and Tukey test (α = 0.05). Mean bond strengths (SD) in MPa were: G1-
32.7 (5.9)A; G2- 31.1 (6.3)A; G3- 25.2 (8.3)B; G4- 36.7 (9.9).A Groups with different uppercase letters were significantly different from each other (p < .05). Enamel bleaching procedure did not affect μTBS values for dentin adhesion. Er:YAG laser irradiation with 25.56 J/cm2 prior to adhesive procedure of bleached teeth did not affect μTBS at dentin and promoted a dentin surface with no smear layer
and opened dentin tubules observed under SEM. On the other hand, Er:YAG laser irradiation prior to adhesive procedure of non-bleached
surface impaired μTBS compared to the control group. 相似文献
12.
The aim of this study was to investigate whether distinct cooling of low fluence erbium, chromium:yttrium-scandium-gallium-garnet
(Er,Cr:YSGG) laser irradiation would influence adhesion. Main factors tested were: substrates (two), irradiation conditions
(three), and adhesives (three). A 750 μm diameter tip was used, for 50 s, 1 mm from the surface, with a 0.25 W power output,
20 Hz, energy density of 2.8 J/cm2 with energy per pulse of 12.5 mJ. When applied, water delivery rate was 11 ml/min. The analysis of variance (ANOVA) showed
that laser conditioning significantly decreased the bond strength of all adhesive systems applied on enamel. On dentin, laser
conditioning significantly reduced bond strength of etch-and-rinse and one-step self-etch systems; however, laser irradiation
under water cooling did not alter bonding of two-step self-etching. It may be concluded that the irradiation with Er,Cr:YSGG
laser at 2.8 J/cm2 with water coolant was responsible for a better adhesion to dentin, while enamel irradiation reduced bond strength, irrespective
of cooling conditions. 相似文献
13.
Decontamination of deep dentin by means of erbium, chromium:yttrium-scandium-gallium-garnet laser irradiation 总被引:1,自引:1,他引:0
Franzen R Esteves-Oliveira M Meister J Wallerang A Vanweersch L Lampert F Gutknecht N 《Lasers in medical science》2009,24(1):75-80
The aim of this in vitro study was to evaluate the depth of effectiveness of erbium, chromium:yttrium-scandium-gallium-garnet
(Er,Cr:YSGG) laser irradiation on microorganism reduction. From human roots, dentin slices of 100 μm to 1,000 μm thickness
were prepared. These specimens were sterilized and then inoculated with 1 μl of Enterococcus faecalis suspension. The backs of the specimens were then irradiated with Er,Cr:YSGG radiation at a pulse energy of 3.13 mJ, delivered
at an incidence angle of 5° to the dentin slice surface. A control group was left without irradiation. The remaining bacteria
were collected in 1 ml sterilized NaCl solution, serially diluted and seeded in Columbia-Agar plates. Despite the low pulse
energy of 3.13 mJ, the Er,Cr:YSGG laser irradiation resulted in significant bacterial reduction up to a dentin thickness of
500 μm (P < 0.05). Scanning electron microscopy (SEM) micrographs of the contaminated and irradiated surfaces showed the absence of
a smear layer and opened dentinal tubules. 相似文献
14.
Camila?Scatena Carolina?Paes?Torres Jaciara?Miranda?Gomes-Silva Marta?Maria?Martins?Giamatei?Contente Jesus?Djalma?Pécora Regina?Guenka?Palma-Dibb Maria?Cristina?Borsatto
The aim of this study was to assess in vitro the influence of Er:YAG laser irradiation distance on the shear strength of the
bond between an adhesive restorative system and primary dentin. A total of 60 crowns of primary molars were embedded in acrylic
resin and mechanically ground to expose a flat dentin surface and were randomly assigned to six groups (n = 10). The control group was etched with 37% phosphoric acid. The remaining five groups were irradiated (80 mJ, 2 Hz) at
different irradiation distances (11, 12, 16, 17 and 20 mm), followed by acid etching. An adhesive agent (Single Bond) was
applied to the bonding sites, and resin cylinders (Filtek Z250) were prepared. The shear bond strength tests were performed
in a universal testing machine (0.5 mm/min). Data were submitted to statistical analysis using one-way ANOVA and the Kruskal-Wallis
test (p<0.05). The mean shear bond strengths were: 7.32 ± 3.83, 5.07 ± 2.62, 6.49 ± 1.64, 7.71 ± 0.66, 7.33 ± 0.02, and 9.65 ± 2.41 MPa
in the control group and the groups irradiated at 11, 12, 16, 17, and 20 mm, respectively. The differences between the bond
strengths in groups II and IV and between the bond strengths in groups II and VI were statistically significant (p<0.05). Increasing the laser irradiation distance resulted in increasing shear strength of the bond to primary dentin. 相似文献
15.
Mir M Meister J Franzen R Sabounchi SS Lampert F Gutknecht N 《Lasers in medical science》2008,23(4):451-457
Different ideas have been presented to describe the mechanism of augmented laser ablation of dental enamel with different
shapes by adding water to the working environment. In this study, the influence of water–laser interaction on the surface
of enamel during ablation was investigated at a wavelength of 2.94 μm with different distances between the laser tip and the
enamel surface. A motion-control system was used to produce linear incisions uniformly on flat enamel surfaces of bovine anterior
teeth, with free-running Er:YAG laser very short pulses (pulse length = 90–120 μs, repetition rate = 10 pulses per second).
Four different output energies (100, 200, 300 and 400 mJ) were radiated on samples under distilled water from different distances
(0.5, 0.75, 1, 1.25, 1.75 and 2.00 mm). The tooth slices were prepared with a cutting machine, and the surfaces of the ablated
areas were measured with software under a light microscope. The average and standard deviation of all cut areas in different
groups were reported. There was no significant difference when using a different pulse ablation speed (cm3/J) and a water-layer thickness between the tip and enamel surface of 0.5–1.25 mm with energy densities of 30–60 J/cm2 (200–400 mJ). However, using an output energy of 15 J/cm2 (100 mJ) and a thicker water layer than 1 mm, a linear ablation did not take place. This information led to a clearer view
of the efficiency of Er:YAG laser in the conditions of this study. There are several hypotheses which describe a hydrokinetic effect of Er,Cr:YSGG. These basic studies could guide us to have a correct attitude regarding hydro-mechanical effects of water, although the wavelength of 2.78 μm has a better absorption in hydroxyl branch of water molecules. Therefore,
our results do not directly interrupt with the series of investigations done with Er,Cr:YSGG. Water propagation and channel
formation under water are investigated during the ablation of tooth enamel with the Er:YAG laser from different distances.
Comparing the results of this study with the same research done with water/air spray concludes that the bubble formation and
channel propagation in water with this wavelength leads to a more symmetric (linear) ablation process with cavity-preparation-recommended
parameters. 相似文献
16.
The aim of this study was to evaluate the influence of different surface treatments (air abrasion, acid etching, laser irradiation)
on the surface roughness of a lithium-disilicate-based core ceramic. A total of 40 discs of lithium disilicate-based core
ceramic (IPS Empress 2; Ivoclar Vivadent, Schaan, Liechtenstein) were prepared (10 mm in diameter and 1 mm in thickness) according
to the manufacturer’s instructions. Specimens were divided into four groups (n = 10), and the following treatments were applied: air abrasion with alumina particles (50 μm), acid etching with 5% hydrofluoric
acid, Nd:YAG laser irradiation (1 mm distance, 100 mJ, 20 Hz, 2 W) and Er:YAG laser irradiation (1 mm distance, 500 mJ, 20 Hz,
10 W). Following determination of surface roughness (Ra) by profilometry, specimens were examined with atomic force microscopy. The data were analysed by one-way analysis of variance
(ANOVA) and Tukey HSD test (α = 0.05). One-way ANOVA indicated that surface roughness following air abrasion was significantly
different from the surface roughness following laser irradiation and acid etching (P < 0.001). The Tukey HSD test indicated that the air abrasion group had a significantly higher mean value of roughness (P < 0.05) than the other groups. No significant difference was found between the acid etching and laser irradiation (both Er:YAG
and Nd:YAG) groups (P > 0.05). Air abrasion increased surface roughness of lithium disilicate-based core ceramic surfaces more effectively than
acid-etching and laser irradiation. 相似文献
17.
Luís Eduardo S. Soares Aldo Brugnera Junior Fátima A. A. Zanin Ana Maria E. Santo Airton A. Martin 《Lasers in medical science》2011,26(5):605-613
The simultaneous need for infection-control protocols in sample preparations and for safe laser irradiation parameters prompted
this study about the effects of heat produced by both sample sterilization and laser etching on dentin components. The dentin
was exposed on 30 bovine incisors, and then divided into two main groups: autoclaved (group A) or thymol treatment (group
B). The surface of the dentin was schematically divided into four areas, with each one corresponding to a treatment subgroup.
The specimens were either etched with phosphoric acid (control-CG) or irradiated with Er:YAG laser (subgroups: I-80 mJ, II-120 mJ,
and III-180 mJ). Elemental distribution maps were done by energy-dispersive X-ray fluorescence (μ-EDXRF) on each treatment
area. The dentin surface in depth was exposed and line-scan maps were performed. The B_CG treatment produced the best distribution
of calcium (Ca) and phosphorus (P) content throughout the dentin surface. Er:YAG laser etching produced irregular patterns
of elemental distribution in the dentin. Laser energies of 120 and 180 mJ produced the highest maximum calcium values. The
Er:YAG laser energy of 180 mJ produced a localized increase in Ca and P content on the superficial layer of the dentin (∼0–0.10 mm).
The autoclaving treatment of samples in experiments is not recommended since it produced damaging effects on dentin components.
Er:YAG laser irradiation produced a heterogeneous Ca and P distribution throughout the dentin surface with areas of increased
Ca concentration, and this may affect clinically the permeability, solubility, or adhesive characteristics of dental hard
tissues with restorative procedures. 相似文献
18.
Letícia Helena Theodoro Denise Maria Zezell Valdir Gouveia Garcia Patrícia Haypek Maria José Hitomi Nagata Juliano Milanezi de Almeida Carlos de Paula Eduardo 《Lasers in medical science》2010,25(4):485-491
The purpose of this study was to evaluate the effect of erbium:yttrium–aluminum–garnet (Er:YAG) laser (2.94 μm) irradiation
on the removal of root surface smear layer of extracted human teeth and to compare its efficacy with that of citric acid,
ethylenediamine tetra-acetic acid (EDTA), or a gel containing a mixture of tetracycline hydrochloride (HCl) and citric acid,
using scanning electron microscopy (SEM). Thirty human dentin specimens were randomly divided into six groups: G1 (control
group), irrigated with 10 ml of physiologic saline solution; G2, conditioned with 24% citric acid gel; G3, conditioned with
24% EDTA gel; G4, conditioned with a 50% citric acid and tetracycline gel; G5, irradiated with Er:YAG laser (47 mJ/10 Hz/5.8 J/cm2/pulse); G6, irradiated with Er:YAG laser (83 mJ/10 Hz/10.3 J/cm2/pulse). Electron micrographs were obtained and analyzed according to a rating system. Statistical analysis was conducted
with Kruskal–Wallis and Mann–Whitney tests (P < 0.05). G1 was statistically different from all the other groups; no statistically significant differences were observed
between the Er:YAG laser groups and those undergoing the other treatment modalities. When the two Er:YAG laser groups were
compared, the fluency of G6 was statistically more effective in smear layer removal than the one used in G5 (Mann–Whitney
test, P < 0.01). Root surfaces irradiated by Er:YAG laser had more irregular contours than those treated by chemical agents. It can
be concluded that all treatment modalities were effective in smear layer removal. The results of our study suggest that the
Er:YAG laser can be safely used to condition diseased root surfaces effectively. Furthermore, the effect of Er:YAG laser irradiation
on root surfaces should be evaluated in vivo so that its potential to enhance the healing of periodontal tissues can be assessed. 相似文献
19.
Silvana Jukić Krmek Ivana Bogdan Paris Simeon Goranka Prpić Mehičić Davor Katanec Ivica Anić 《Lasers in medical science》2010,25(6):823-828
The aim of this study was to evaluate microleakage along resin restoration in cavities prepared with an erbium:yttrium–aluminium–garnet
(Er:YAG) laser, with and without acid etching, and to compare it with that in diamond-drilled cavities. Thirty intact molars
were divided into three equal groups. In the teeth in group I, class V cavities were prepared with a diamond drill. Cavities
in groups II and III were prepared with an Er:YAG laser (400 mJ/15 Hz for enamel and 250 mJ/10 Hz for dentine). The cavities
in groups I and II were acid-etched and adhesive and flowable composite were applied to all cavities. The specimens were first
immersed in dye for 24 h and then in 5% nitric acid for 72 h for softening. The fillings were extracted and photographed through
a dissecting microscope. The leakage area was measured with specially designed software. The Kruskal–Wallis test showed that
the best ranking was group II [mean range (m.r.) = 27.46], followed by group I (m.r. = 33.48) and, lastly, group III (m.r. = 45.15).
The differences between groups I and III (P = 0.023) and between groups II and III were statistically significant (P = 0.080). The least microleakage was found in those cavities prepared by Er:YAG laser and subsequently acid-etched, whereas
the most leakage was in the lased cavities that had not been etched; the traditional diamond-drilled acid-etched cavities
produced medium leakage. 相似文献
20.
Effect of erbium:yttrium-aluminum-garnet laser energies on superficial and deep dentin microhardness
This study evaluated the microhardness of superficial and deep dentin irradiated with different erbium:yttrium–aluminum–garnet
(Er:YAG) laser energies. Seventy-two molars were bisected and randomly assigned to two groups (superficial dentin or deep
dentin) and into six subgroups (160 mJ, 200 mJ, 260 mJ, 300 mJ, 360 mJ, and control). After irradiation, the cavities were
longitudinally bisected. Microhardness was measured at six points (20 μm, 40 μm, 60 μm, 80 μm, 100 μm, and 200 μm) under the
cavity floor. Data were submitted to analysis of variance (ANOVA) and Fisher’s tests (α = 0.05). Superficial dentin presented
higher microhardness than deep dentin; energy of 160 mJ resulted in the highest microhardness and 360 mJ the lowest one. Values
at all points were different, exhibiting increasing microhardness throughout; superficial dentin microhardness was the highest
at 20 μm with 160 mJ energy; for deep dentin, microhardness after irradiation at 160 mJ and 200 mJ was similar to that of
the control. The lowest energy increased superficial dentin microhardness at the closest extent under the cavity; deep dentin
microhardness was not altered by energies of 160 mJ and 200 mJ. 相似文献