Longevity of diode laser irradiation in dentine

Abstract

The efficacy of pulsed infrared lasers on clinical dentin wear sensitivity is well stablished in the Literature. This work aims to evaluate the effect of diode laser combined with fluoride products regarding the longevity of the sensibility treatment under the effect of the domestic use products. After Ethics Committee approval, 75 slabs of bovine root dentin measuring 8 mm2, were randomized into 5 groups (n=1 5): G1- untreated; G2- treated with acidulated phosphate fluoride (APF-gel, [F-J=1.23 %, pH=3.3 to 3.9); G3- irradiated with diode laser (980 nm, 2.5W, 5ms, 25Hz) using a cool paste as photoabsorber; G4- irradiated with diode laser (same conditions of G3) using a coal paste as photoabsorber + application of APF-gel and G5- application of APF-gel+ diode laser irradiation (same conditions of G3). All samples were submitted to an erosive and abrasive demineralization (Sprite Zero, pH=2.8, 90s, 4x/day), and remineralization (artificial saliva, pH=7.4) cycling for 10 days. Twice a day, slabs were brushed for 15s using a whitening dentifrice (Sensodyne True White, GSK, EUA). Slabs were evaluated by Optical Coherence Tomography (OCT) at the initial and 7th day of cycling. OCT measurements found a significant increase on dentin wear depth and area of lesions with the increase of cycling days. G1 and G2 hod significant higher mineral loss compared to the other groups. G3, G4 and GS showed no significant differences between them. Results suggested that the sensibility of the treatment with the diode laser has longevity despite the high abrasivity of dentifrice used in maintenance.