Effect of Photobiomodulation on Relapse in an Experimental Rapid Maxillary Expansion Model in Rat

Rapid maxillary expansion (RME) is performed on transversely deficient maxilla. As all orthodontic treatments, retention is important in maintaining therapeutic outcomes. Fixed /removable retainers are used post‐RME causing hygiene and compliance problems. Given photobiomodulation’s positive effects on the quantity and quality of bone regeneration, its effect on post‐RME relapse was studied. Thirty Sprague Dawley rats were randomly divided into group R, non‐irradiated RME‐treated (n = 12), group P, irradiated RME‐treated (n = 12) and group C, non‐RME non‐irradiated (n = 6). A 1.5 mm metal ring inserted between maxillary incisors at days 0 and 15 was expanded until 1.5 mm space was obtained at day 30. In group P, Ga‐Al‐As diode laser (810 nm, 100 mW, 4J/cm2, 30 secs) was applied on days 0, 2, 4, 6, 8, 10, 12 and 14 as predictor variable. The relapse was measured as the space lost between incisors for 30 days after appliance removal (primary outcome variable) and compared with t‐test. In week 2, space loss in group P was significantly lower (P