Clinical effects of 532 nm picosecond and nanosecond Nd∶YAG laser in treatment of early seborrheic keratosis / 中华医学美学美容杂志

Objective:To compare the efficacy and adverse reactions of picosecond and nanosecond Nd∶YAG laser 532 nm in the treatment of seborrheic keratosis.Methods:A total of 30 patients with seborrheic keratosis were enrolled in this study. The rash size was more than 1-2 cm. Half of them were treated with picosecond laser and the other half with nanosecond Q-switched Nd∶YAG laser by wavelength of 532 nm. The treatment effect and adverse reactions were evaluated by observing the area and the disappearance of pigment. The patients were followed up for 3 months after treatment.Results:The total effective rate was 73.33% in the experimental group and 53.33% in the control group, with no significant difference between the two groups ( P>0.05), but the pain score, satisfactory score, scab shedding time and the incidence of pigmentation in the experimental group were lower than those in the control group, and the differences were statistically significant ( P<0.05). Conclusions:The 532 nm picosecond laser has a higher efficiency in treating seborrheic keratosis than 532 nm Q-switched Nd∶YAG, but it has no statistical significance. However, the self satisfaction is higher than that of the control group; the pain score, scab shedding time and the incidence of pigmentation are lower than those of the control group, with statistical significance. Therefore, picosecond 532 nm laser treatment of early seborrheic keratosis is worthy of clinical promotion.

A Split-Face, Single-Blinded, Randomized Controlled Comparison of 532 nm Picosecond Neodymium-Doped Yttrium Aluminum Garnet Laser versus 532 nm Q-Switched Neodymium-Doped Yttrium Aluminum Garnet Laser in the Treatment of Solar Lentigines

A study on the processing of dental ceramic composites by using laser / 대한치과보철학회지

PURPOSE: The laser processability of dental prosthesis is investigated using two ceramic composites, including 3M, Lava Ultimate and Ivoclar vivadent, IPS e.max. MATERIALS AND METHODS: The CO₂ laser, picosecond laser and femtosecond laser are used to assess the processing power of dental prosthetic materials Lava Ultimate and IPS e.max and the line processing shape was measured using a confocal microscope. RESULTS: The brittleness, carbonization and micro crack of the ceramic composite were influenced by heat accumulation of the material and could be controlled by the laser power and pulse time. CONCLUSION: In the case of CO₂ lasers, micro crack and carbonation occurred immediately, and in the picosecond laser processing, the micro cracks are partially improved, but the carbonization occurs continuously. Finally, we confirmed the high efficiency of laser processing with femtosecond laser. In particular, Lava Ultimate, a ceramic resin composite material, showed the best processability when processed using a femtosecond laser.

Safety and efficacy of picosecond Alexandrite laser with a diffractive lens array for treatment of facial photoaging / 中华医学美学美容杂志

Objective To evaluate the efficacy and safety of a 755 nm picosecond Alexandrite la-ser with a diffractive lens array in the treatment of facial photoaged skin .Methods Twenty-six pa-tients with facial photoaging were recruited and received 3 treatments at 4-week intervals .Laser energy was applied over the entire face at a fixed spot size of 6 mm ,with a fluence of 0 .71 J/cm2 and 5Hz . Blinded clinical assessment was performed by 2 independent dermatologists on a 5-point global pho-toaging scale (GPS) .Patients were also questioned on the extent of improvement of rhytides ,skin tightening ,and complexion with a 4-point global aesthetic improvement scale (GAIS) and satisfaction . Adverse events were also evaluated .Results Twenty-six patients completed the treatment .Compared with the baseline ,there was a significant improvement in facial photoaged skin after 3 treatments ,and these positive outcomes were maintained up to the 3-month follow-up ,according to the GPS and GAIS scores .Moderate pain and transient erythema were observed as the two main discomforts associated with the treatment .Most patients were satisfied with the treatment .Conclusions This 755 nm pico-second Alexandrite laser with a diffractive lens array optic is effective in the treatment offacial pho -toaged skin ,and the therapy also seems safe and well tolerated .

Quantitative comparative analysis of 755 nm picosecond laser and intense pulsed light for facial freckles / 中华整形外科杂志

Objective@#To observe the efficacy of 755 nm picosecond laser and intense pulsed light in the treatment of facial freckles.@*Methods@#Sixty-six outpatients with freckles were randomly divided into two groups. They were treated with 755 nm picosecond laser (P755 nm) and intense pulsed light (IPL), respectively. Frequent freckles were analyzed before treatment and at 4 week after treatment.@*Results@#Both treatments had good curative effect, but the P755 nm group had better efficacy than the IPL group with significant difference.@*Conclusions@#755 nm picosecond laser and IPL can treat freckles very well, and P755 nm group is superior to IPL.

Treatment of Melasma and Post-Inflammatory Hyperpigmentation by a Picosecond 755-nm Alexandrite Laser in Asian Patients

The picosecond lasers have shown to effectively treat tattoo pigments that are intractable to previous multiple Q-switched (QS) laser treatments. Therefore we hypothesized that a picosecond laser would show better efficacy with minimal adverse events in the treatment of melasma and post-inflammatory hyperpigmentation (PIH) that are difficult to treat with conventional QS lasers. Two patients with melasma and one patient with PIH were treated with a Picosecond 755-nm Alexandrite Laser (Cyanosure, USA). All patients were Korean with skin type IV and no longer responding to QS laser treatments. Laser treatment was well tolerated in all the patients. Adverse events such as PIH were not reported during 8 weeks of follow up period. After the multiple treatment sessions, one patient reported fair improvement and two patients reported good improvement. Consistent with the clinical results, ex vivo skin model irradiated with a Picosecond 755-nm Alexandrite Laser also showed decreased epidermal keratinocyte necrosis compared with the 532-nm QS Neodymium-Doped Yttrium Aluminium Garnet Laser (Lutronic, Korea) yet decreased melanin content. In conclusion, the Picosecond 755-nm Alexandrite Laser may be useful for effective treatment of intractable melasma and PIH with fewer adverse events in dark Asian skin.

Effect of 532 nm picosecond Nd∶YAG laser irradiation on temperature of the pulp chamber / 国际生物医学工程杂志

Objective To preliminarily select safe parameters for different forms of teeth by irradiating 532 nm picosecond Nd∶YAG laser on human isolated teeth with different irradiation time length and power.Methods Isolated human teeth including anterior teeth,premolars,molars were irradiated with 532 nm picosecond laser.Repeated measurements were made for each tooth by thermometer to measure the temperature of pulp chamber on different time point and power,and the temperature change (△T) was calculated.Results △T of the anterior irradiation group at 0.6 W,30 s;0.8 W,20 s and 30 s;1.0 W,10 s,20s and 30s were more than 5.6 ℃,which was the same with that of premolar group at 1.0 W,30s.△T of the molar group at 1.0 W,30 s was less than 5.6 ℃.Under certain power,the temperature of pulp chamber increased with the prolonging of irradiation time (P＜0.05).At a certain time,temperature increased with the power (P＜0.05).Conclusions It is safe to carry out operation on the parameters setting of 0.8 W,10 s and 0.6 W,20 s irradiation for anteriors teeth;0.4 W,30 s,0.8W,30 s and 1.0 W,20 s for premolar teeth,and 1 W,30 s for molar teeth.In the application of 532 nm picosecond laser,attention is required to be paid on parameter setting to control input power and irradiation time.

Influence of picosecond pulse electric field to invasive ability of cervical cancer / 解放军医学杂志

Objective To investigate the influence of picosecond pulse electric field (psPEF) to the invasive ability of cervical cancer. Methods The model of cervical cancer was reproduced in BALB/c nude mice (n=24), and they were randomly divided into four groups (n=6) when the xenografts had grown reaching a diameter of 0.8-1.0cm: control group (psPEF was not given), low field intensity group (50kV/cm), moderate field intensity group (60kV/cm) and high field intensity group (70kV/cm). Seven days after the psPEF treatment, the histomorphological changes were observed with HE staining and transmission electron microscopy (TEM), the expressions of vascular endothelial growth factor (VEGF) and matrix metalloproteinases-9 (MMP-9) were determined with immunohistochemical (IHC) staining, and the changes in protein level of VEGF and MMP-9 were assessed with Western blotting. ResultsAfter psPEF treatment, the area of necrosis was found to be increased with an increase in psPEF intensity. With TEM different degrees of apoptosis and necrosis in tumor cells with an increase of psPEF intensity were found. IHC showed that the number of VEGF and MMP-9 positive cells in cancer tissue was decreased with an increase in psPEF intensity. The average optical density (AOD) of VEGF and MMP-9 proteins decreased significantly in psPEF treatment groups compared with that in control group, and the AOD values in psPEF treatment groups decreased with an increase in psPEF intensity, and the decrease was statistically significant (P<0.05). Western blotting showed the expressive levels of VEGF and MMP-9 proteins declined gradually with an increase in psPEF intensity, and the difference between groups was statistically significant (P<0.05). Conclusion psPEF may have anti-cervical cancer effects by inhibiting the secretion of VEGF and MMP-9 and reducing the invasive ability of cervical cancer cells.