Comparison between the effect of low-level laser therapy and low-intensity pulsed ultrasonic irradiation in vitro.
OBJECTIVE
The objective of this study was to compare the effect of low-level laser therapy (LLLT) and low-intensity pulsed ultrasound (LIPUS) on fibroblast cell culture. Several methods, including ultrasound treatment and LLLT, are being used to facilitate tissue repair and healing processes.


METHODS
L929 fibroblast cell cultures were irradiated with low-level laser energy and LIPUS. Cultures irradiated with ultrasound were divided into five groups: group 1: control (did not receive irradiation); group 2: 0.2 W/cm(2) in pulsed mode at 10% (1:9 duty cycle); group 3: 0.6 W/cm(2) in pulsed mode at 10% (1:9 duty cycle); group 4: 0.2 W/cm(2) in pulsed mode at 20% (2:8 duty cycle); and group 5: 0.6 W/cm(2) in pulsed mode at 20% (2:8 duty cycle). Cultures irradiated with laser energy were divided into three groups: group 1: control (did not receive irradiation); group 2: 6 J/cm(2); and group 3: 50 mJ/cm(2). Each group was irradiated at 24-h intervals, with the following incubation periods post-irradiation: 24, 48, and 72 h; after each irradiation cycle the cultures were analyzed using MTT [3-(4.5-dimethylthiazol-2-yl)-2.5 diphenyltetrazolium bromide].


RESULTS
Analysis of results after LLLT and LIPUS demonstrated that the effect of laser therapy on fibroblast cell culture was greater than that of LIPUS (p < 0.05).


CONCLUSIONS
Results demonstrated that LLLT significantly increased fibroblastic activity more than LIPUS. Therefore, in the first and second phases of tissue repair, laser treatment may be more effective than ultrasound treatment.
De Oliveira
Rodrigo Franco
RF
Laboratório de Dinâmica de Compartimento Celular, Instituto de Pesquisa e Desenvolvimento (IP&D), UNIVAP, São José dos Campos, São Paulo, Brazil.
Oliveira
Deise A A Pires
DA
Monteiro
Wagner
W
Zangaro
Renato Amaro
RA
Magini
Márcio
M
Soares
Cristina Pacheco
CP
D000818:Animals; D018929:Cell Culture Techniques; D005347:Fibroblasts / Q000502:physiology / Q000528:radiation effects*; D028022:Low-Level Light Therapy; D051379:Mice; D014464:Ultrasonic Therapy