Effect of photobiomodulation therapy on orthodontic-induced inflammatory root resorption in male albino rats.

BACKGROUND: This study aimed to assess histologically and histomorphometrically the effect of Photo-biomodulation therapy (PBM) on orthodontic-induced inflammatory root resorption (OIIRR) under relatively light- and heavy- orthodontic forces in rats. METHODS: Thirty-two male Albino rats weighing between (250–300 g) were randomly assigned to four equal groups (gp) of 8 rats each. Control low-force gp (CL): The maxillary left 1st molar (M1) was subjected to 10–15 g orthodontic force by nickel titanium coil spring stretched between the M1 and maxillary incisors. Control high-force gp (CH): The M1 had heavier orthodontic force of 50 g. Laser low-force gp (LL): The M1 had orthodontic force of 10–15 g & PBM using GaAlAs diode laser (λ = 980 nm, 100 mW output power) at two points palatal and two buccal, with a continuous non-contact irradiating mode for 12 s for each point (energy of 1.2 J/point, fluence of 16.9 J/cm2). Laser high-force gp (LH): M1 had orthodontic force of 50 g & PBM. The rats were euthanized after 7- and 21-days intervals in each gp and the maxillae were dissected out, then serial transverse sections of the M1 were taken for histological and histomorphometric evaluation. RESULTS: Our results showed significant decrease in the amount of OIIRR in the laser gps at day 21 in all force subgroups, without significant change at day 7. CONCLUSION: PBM can significantly reduce the overall amount of root resorption and enhance/accelerate the healing of OIIRR.