Effect of single and multiple doses of low-level laser therapy on viability and proliferation of stem cells from human exfoliated deciduous teeth (SHED).

The present study aimed to evaluate in vitro whether the low-level laser (LLL) delivering fractionated total energy (multiple irradiation) or single irradiation stimulates regeneration-associated events (viability and proliferation) in stem cells from human exfoliated deciduous teeth (SHED). Cells received LLL irradiation (InGaAlP-660 nm), according to the following experimental groups: G1 (single irradiation 2.5 J/cm2, 10 mW, 10 s, 0.10 J), G2 (single irradiation 5.0 J/cm2, 10 mW, 20 s, 0.20 J), G3 (single irradiation 7.5 J/cm2, 10 mW, 30 s, 0.30 J), G4 (two irradiations 2.5 J/cm2, 10 mW, 10 s; total energy 0.20 J), G5 (three irradiations 2.5 J/cm2, 10 mW, 10 s; total energy 0.30 J), and G6 (non-irradiated). Cell viability was assessed by MTT and trypan blue exclusion (TBE) methods, while cell proliferation was evaluated by crystal violet (CV) and sulforhodamine B (SRB) assays after 24, 48, and 72 h after the first irradiation. By MTT, there was no difference between groups at 24 and 72 h. At 48 h, the groups subjected to multiple irradiation (G4 and G5) presented higher cell viability rates. The average percentages of viable cells for all groups by TBE method were 91.04%, 96.63%, and 97.48% at 24, 48, and 72 h, respectively. By CV, there was no significant difference between groups at 24 and 48 h; at 72 h, G2, G3, and G4 presented higher cell proliferation. By SRB, G1 and G4 presented lower proliferation rates in all the periods. When the groups presenting the same total energy were compared, G2 (0.20 J) presented lower cell viability rates and higher cell proliferation rates in comparison with G4; G3 (0.30 J) presented similar results to those of G5, with higher cell viability and proliferation. The application of laser delivering fractionated total energy (two or three applications of 2.5 J/cm2) induced higher cell viability at 48 h, while the single irradiation with 2.5 J/cm2 did not stimulate metabolic activity in such period and the proliferation over time. The 5.0 and 7.5 J/cm2 single doses and the three applications of 2.5 J/cm2 maintained cell viability and stimulated proliferation of SHED at 72 h.

Effective method for the detection of piroxicam in human plasma using HPLC

Abstract Non-steroidal anti-inflammatory drugs (NSAIDs) are widely used by the general population to alleviate inflammation and pain after oral surgeries. Piroxicam is among the most commonly used NSAIDs and excels in controlling pain, swelling, trismus and other common symptoms of inflammation. This study aimed to evaluate different concentrations of piroxicam and its major metabolite, 5'-hydroxypiroxicam, in human plasma samples over time using high performance liquid chromatography (HPLC) after liquid-liquid extraction. Briefly, 10 volunteers participated in this study after approval by the Ethics Committee of Bauru School of Dentistry, Universidade de São Paulo - USP, Brazil. Volunteers received a single dose oral of piroxicam (20 mg) and had blood collected at various times following an established protocol. The methodology of liquid-liquid extraction was effective for determining concentrations of piroxicam in plasma using HPLC in 10 out of 10 volunteers while 5'-hydroxypiroxicam was only detected in 2 out of 10 volunteers.