The effect of He-Ne and Ga-Al-As laser light on the healing of hard palate mucosa of mice

Abstract

Low-level laser therapy (LLLT) has been used to accelerate wound healing, yet questions remain concerning its therapeutic applications. This study aimed to compare the healing efficacy of helium-neon (He-Ne) red light (laser) and gallium aluminum arsenide (Ga-Al-As) infrared lasers at two different doses on hard palate wounds. In a randomized controlled study, 75 adult male mice were divided into five groups of 15 each, after undergoing identical surgical procedures; a control group, with no laser irradiation; HD1 and HD2 groups, treated with He-Ne laser (wavelengths 632.8 nm, power 5 mW, and spot size 0.02 cm(2)) at doses of 4 J/cm(2) and 7.5 J/cm(2) respectively; and GD1 and GD2 groups, treated with Ga-Al-As laser (wavelengths 830 nm, peak power 25 mW, and spot size 0.10 cm(2)) at the doses of 4 J/cm(2) and 7.5 J/cm(2), respectively. Five animals from each group were killed on the third, seventh, and 14 days after surgery, and biopsies were made for histological analysis. On the 3rd and 7th day after the surgery, the number of polymorphonuclear cells (PMN) in HD1, HD2, GD1, and GD2 groups was significantly lower than that of the control group. On the 7th and 14th day, the fibroblasts and new blood vessels counts and collagen density fibers in HD1, HD2, GD1, and GD2 groups were also significantly higher than that of the control groups, and the fibroblast counts and collagen density fibers in HD1 and HD2 groups were higher than that of the GD1 and GD2 groups. LLLT with He-Ne laser compared to Ga-Al-As laser has a positive healing effect on hard palate gingival wounds in mice regardless of the radiation dose.

Comparison of two power densities on the healing of palatal wounds after connective tissue graft removal: randomized clinical trial

“…This result can probably be explained by the effects of the GaAIAs laser wavelength and the applied dose on the secretory activity of fibroblasts, as well as their influence on the pro-and anti-inflammatory cytokines during early stages of repair, as previously reported [12,14,22]. A study conducted by Mendez et al [23] compared the influence of 20 and 50 J/ cm 2 doses on skin wound closure in rats; after 3 days repair, the group treated with 50 J/cm 2 had histologically significant regressions of inflammation and the presence of organized collagen matrix, with reduced collagen deposition noted after 5 days of healing.…”

“…Diverse studies have used wavelengths between 680 and 840 nm, which are related to the most efficient tissue biostimulation [12]. Evidence regarding the healing efficacy of low-level laser therapy techniques using gallium aluminum arsenide (Ga-Al-As) infrared lasers at different doses on hard palate wounds in mice showed that laser application has a positive healing effect on the healing process [14].…”

Effect of red and near-infrared wavelengths on low-level laser (light) therapy-induced healing of partial-thickness dermal abrasion in mice

“…In this study, we demonstrated that both, red (635 nm) and NIR (810 nm) light can significantly enhance the healing of partial-thickness dermal abrasions. Similarly, other studies have also reported that He-Ne laser (632.8 nm) and other wavelengths (660–670 nm) irradiation at fluence of 1–6 J/cm 2 stimulated healing in normal and impaired wounds (burns and diabetic) by re-epithelialization and granulation tissue formation [8, 9, 11, 27, 28]. …”

The effect of low‐level laser therapy on the healing of hard palate mucosa and the oxidative stress status of rats

“…Fahimipour et al. suggested that LLLT inhibits severe inflammatory reactions and promotes collagen formation with diode laser wavelengths of 685 and 830 nm at doses of 3.95 and 7.9 J/cm2.…”

“…. The density of collagen fibers was scored according to the following scale: 1 = few collagen fibers, 2 = few and partially spread collagen fibers, 3 = few and fully spread collagen fibers, and 4 = dense collagen fibers (Tables and ). To avoid observer bias, the histologist was blinded to the study groups, and the data were recorded with respect to the sample codes.…”