Comparative clinical evaluation of the immediate and late analgesic effect of GaAlAs diode Lasers of 830 nm and 660 nm in treatment of dentine pain - Preliminary results

In this comparative clinical study, we aimed at evaluating the immediate and late analgesic effect of GaAlAs diode lasers of 660 nm and 830 nm in treatment of dentine pain.We used GaAlAs diode lasers of 660 nm and 830 nm with 35 mW, continuous wave emission, spot size 1 mm(2) and a dosage of 4 joules/cm(2) applied to the cervical dentine surface. in total 4 treatment sessions were performed at intervals of 7 days in a period of 4 consecutive weeks.A total of 40 teeth treated were divided into two groups comprising 20 teeth each: one group irradiated with a 660 run wavelength laser, and the other one with a 830 nm wavelength laser.By means of a quantitative visual analogue scale (V.A.S.), we measured the sensitive responses to cold stimulus pretreatment, and at a follow-up period of 15 and 30 minutes post-treatment in both groups in order to evaluate the immediate analgesic effect. the late effect was evaluated at a follow-up period of 15 and 30 days.Using the GaAlAs diode laser of 660 nm wavelength resulted in better levels of dentine desensitization, at both inmediate and late analgesic effect analysis compared with the use of the GaAlAs diode laser of 830 run wavelength.Universidade Federal de São Paulo, EPM, São Paulo, BrazilUniversidade Federal de São Paulo, EPM, São Paulo, BrazilWeb of Scienc

Comparative clinical study of the effect of LLLT in the immediate and late treatments of hypoesthesia due to surgical procedures

We evaluated the effect of LLLT in 68 patients who presented hypoegthesia due to odontological surgery procedures: dental implant surgeries (N=51); extraction of impacted lower third molars (N=10); endodontics in lower first molars (N=7).Lesions treated within 30 days after the nerve injury had occurred were part of the immediate group, and lesions with more than 30 days from the occurrence of the injury were part of the late group. mm(2),Treatments were carried out with an infrared diode laser of 40 mW - 830nm, continuous wave emission, spot size 3 and a total dosage of 18 joules per session in a contact mode application, 20 sessions altogether.The efficacy of laser therapy in peripheral nerve regeneration is also related to the degree of the peripheral nerve lesion, and not only to the lesion duration.LLLT resulted in neurosensory functional improvement in both immediate and late treatments of hypoesthesia.Universidade Federal de São Paulo, EPM, São Paulo, BrazilUniversidade Federal de São Paulo, EPM, São Paulo, BrazilWeb of Scienc

In vitro effect of low intensity laser on the cytotoxicity produced by substances released by bleaching gel

This in vitro study aimed to analyze the effect of different parameters of phototherapy with low intensity laser on the viability of human dental pulp fibroblasts under the effect of substances released by bleaching gel. Cells were seeded into 96 wells plates (1 x 10³ cells/well) and placed in contact with culture medium conditioned by a 35 % hydrogen peroxide bleaching gel for 40 minutes, simulating the clinical condition of the in-office bleaching treatment. Cells cultured in ideal growth conditions served as positive control group (PC), and the cells grown in conditioned medium and non-irradiated served as negative control group (NC). Cells grown in conditioned medium were submitted to a single irradiation with a diode laser (40 mW, 0.04 cm²) emitting at visible red (660 nm; RL) or near infrared (780 nm; NIR) using punctual technique, in contact mode and energy densities of 4, 6 or 10 J/cm². The cell viability was analyzed through the MTT reduction assay immediately and 24 hours after the irradiation. The data was compared by ANOVA followed by the Tukey's test (p < 0.05). The cell viability increased significantly in 24 hours within each group. The PC presented cell viability significantly higher than NC in both experimental times. Only the NIR/10 J/cm² group presented cell viability similar to that of PC in 24 hours. The phototherapy with low intensity laser in defined parameters is able to compensate the cytotoxic effects of substances released by 35 % hydrogen peroxide bleaching gel