Effects of 405-, 532-, 650-, and 940-nm wavelengths of low-level laser therapies on orthodontic tooth movement in rats

Abstract

Background Investigating the effects of 405-nm, 532-nm, 650-nm, and 950-nm wavelengths of LLLTs (low-level laser therapies) on the orthodontic tooth movement in rats by using histological and immunohistochemical methods. Forty-five Wistar albino rats were randomly divided into 5 groups: control group (positive control: the left maxillary 1st molar side; negative control: the right maxillary 1st molar side), 405 nm LLLT group (Realpoo), 532 nm LLLT group (Realpoo), 650 nm LLLT group (Realpoo), and 940 nm LLLT group (Biolase). The left maxillary 1st molar teeth of all rats were applied mesially 50-g force. Starting from the 1st day, 48 h intervals, LLLT was applied in continuous wave mode and in contact with the tissue. The application area was approximately 1 cm2. The lasers were performed for 3 min on each surface (buccal, palatal, mesial), totally 9 min (total dose 54 J/cm2). The amount of the molar mesialization, the bone area between the roots, PDL (periodontal ligament) measurements, TRAP (tartrate-resistant acid phosphatase), and ALP (alkaline phosphatase) immunoreactivity intensity were calculated. Results The amount of the molar mesialization was significantly higher in the 650 nm LLLT group (mean 0.878 ± 0.201 mm; 95% CI (confidence interval) 0.724 and 1.032) than in the groups of positive control (mean 0.467 ± 0.357 mm; 95% CI 0.192 and 0.741) and 405 nm LLLT (mean 0.644 ± 0.261 mm; 95% CI 0.443 and 0.845) (p < 0.001). There were significant differences in the PDL-mesial (p = 0.042) and PDL-distal (p = 0.007) regions between the groups. The immunoreactivity intensity for TRAP-mesial was significantly higher in the positive control group (mean 109,420.33 ± 8769.17; 95% CI 100,217.65 and 118,623.02) than in the 405 nm (mean 91,678.83 ± 7313.39; 95% CI 84,003.9 and 99,353.77) and the 650 nm LLLT (mean 87,169.17 ± 4934.65; 95% CI 81,990.56 and 92,347.77) groups (p = 0.002). There was no statistically significant difference between the groups on immunoreactivity intensity with ALP staining. Conclusions The results of this study show that LLLT with 650-nm wavelength increases orthodontic tooth movement more than 405-nm, 532-nm, and 940-nm LLLTs. The 940-nm and 650-nm LLLTs also increase the bone area between the roots by more than 405-nm and 532-nm wavelengths.

Comparison of Wavelength-Dependent Penetration Depth of 532 nm and 660 nm Lasers in Different Tissue Types

“…Studies have shown that near-infrared light can penetrate biological tissues more effectively than visible light. 18,19 Existing interpretations suggest that light energy emitted by laser therapy devices is predominantly absorbed within the first 10 mm of biological tissue. This finding aligns with previous research indicating that laser light can penetrate several millimeters into biological tissues.…”

The Effects and Mechanisms of PBM Therapy in Accelerating Orthodontic Tooth Movement

“…From these results, it is not difficult to see that there are different light parameters in different articles, especially wavelengths (Table 1). Keklikci et al [42] found that 650 nm and 940 nm light presented better osteogenic ability in the area between the roots than 405 nm and 532 nm light, and 405 nm light formed the least bone, which could be attributed to increased intracellular oxygen radicals [43]. Furthermore, 650 nm light could decrease osteoclastogenesis by reducing intracellular oxygen radicals [43].…”

Photobiomodulation in Orthodontics: Mechanisms and Clinical Efficacy for Faster Tooth Movement

“…Despite the advantages, the application of PBM in orthodontics is met with several challenges. The absence of standardized treatment protocols is a primary limitation, introducing variability in treatment parameters and outcomes [28,[42][43][44][45][46]. This variability is compounded by individual differences in response to PBM, which can hinder the development of universal treatment guidelines [28].…”

“…Moreover, the effective utilization of PBM devices requires specific clinician training to prevent potential misuse or excessive use, which could lead to tissue damage. Another significant barrier to the widespread adoption of PBM is the cost of laser equipment, which, along with the need for intensive safety training, may limit accessibility for some practices and patients [24,25,[38][39][40][41][42][43][44][45][46].…”