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

Abstract

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/cm 2 , 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 < 0.05) than all other groups. The relapse during weeks 2 and 3 was significantly lower in group P than group R. However, no significant difference in relapse amount was found between groups during first and fourth week. There was a significant difference (P < 0.05) between groups in relapse rates (secondary outcome variable) but not in total relapse after 4 weeks. Photobiomodulation proved beneficial in resisting relapse in our study, and it is suggested to be continued until the end of expansion.

The Effects of Thymoquinone and Vibration Forces on Rapid Palatal Expansion Relapse in Experimental Rat Models

“…Since the success of premaxillary suture expansion in the RPE procedure is less after pubertal development, 8-week-old male rats with an average weight of 200 g, similar to the rats used in the studies of Pirmoradian et al [18], H. Wang et al [19] and Wang et al [20], were used in this study. By examining similar studies, the force applied to separate the palatal sutures was 50 g and the thickness of the expander spring used was 0.014-inch, and since it was suitable for the RPE procedure, wires with the same properties and expanding force were applied in this study [21,22].…”