Effect of low-level GaAlAs laser irradiation on the proliferation rate of human periodontal ligament fibroblasts: an in vitro study.

AIM

The aim of this in vitro study was to evaluate a potential stimulatory effect of low-level laser irradiation on the proliferation of human periodontal ligament fibroblasts (PDLF).

MATERIALS AND METHODS

PDLF obtained from third molar periodontal ligaments were cultured under standard conditions and spread on 96-well tissue culture plates. Subconfluent monolayers were irradiated with an 809-nm diode laser operated at a power output of 10 mW in the continuous wave (cw) mode at energy fluences of 1.96-7.84 Jcm-2. The variable irradiation parameters were the time of exposure (75-300 s per well) and the number of irradiations (1-3). After laser treatment, the cultures were incubated for 24 h. The proliferation rate of the lased and control cultures was determined by means of fluorescence activity of a reduction-oxidation (REDOX) indicator (Alamar Blue Assay) added to the cell culture. Proliferation, expressed in relative fluorescence units (RFU), was determined 24, 48 and 72 h after irradiation.

RESULTS

The irradiated cells revealed a considerably higher proliferation activity than the controls. The differences were significant up to 72 h after irradiation (Mann-Whitney U-test, p<0.05).

CONCLUSION

A cellular effect of the soft laser application is clearly discernible. Clinical studies are needed to evaluate whether the application of low-level laser therapy might be beneficial in regenerative periodontal therapy.