title: Effect of a low-level laser on bone regeneration after rapid maxillary expansion.
abstract: BACKGROUND
  In this study, we evaluated the effects of a low-level laser on bone regeneration in rapid maxillary expansion procedures.
  
  
  METHODS
  Twenty-seven children, aged 8 to 12 years, took part in the experiment, with a mean age of 10.2 years, divided into 2 groups: the laser group (n = 14), in which rapid maxillary expansion was performed in conjunction with laser use, and the no-laser group (n = 13), with rapid maxillary expansion only. The activation protocol of the expansion screw was 1 full turn on the first day and a half turn daily until achieving overcorrection. The laser type used was a laser diode (TWIN Laser; MMOptics, São Carlos, Brazil), according to the following protocol: 780 nm wavelength, 40 mW power, and 10 J/cm(2) density at 10 points located around the midpalatal suture. The application stages were 1 (days 1-5 of activation), 2 (at screw locking, on 3 consecutive days), 3, 4, and 5 (7, 14, and 21 days after stage 2). Occlusal radiographs of the maxilla were taken with the aid of an aluminum scale ruler as a densitometry reference at different times: T1 (initial), T2 (day of locking), T3 (3-5 days after T2), T4 (30 days after T3), and T5 (60 days after T4). The radiographs were digitized and submitted to imaging software (Image Tool; UTHSCSA, San Antonio, Tex) to measure the optic density of the previously selected areas. To perform the statistical test, analysis of covariance was used, with the time for the evaluated stage as the covariable. In all tests, a significance level of 5% (P <0.05) was adopted.
  
  
  RESULTS
  From the evaluation of bone density, the results showed that the laser improved the opening of the midpalatal suture and accelerated the bone regeneration process.
  
  
  CONCLUSIONS
  The low-level laser, associated with rapid maxillary expansion, provided efficient opening of the midpalatal suture and influenced the bone regeneration process of the suture, accelerating healing.
authors.affiliation: Methodist University of São Paulo, São Paulo, Brazil.
authors.forename: Fernanda
authors.initials: F
authors.lastname: Cepera
authors.forename: Fernando C
authors.initials: FC
authors.lastname: Torres
authors.forename: Marco A
authors.initials: MA
authors.lastname: Scanavini
authors.forename: Luiz R
authors.initials: LR
authors.lastname: Paranhos
authors.forename: Leopoldino
authors.initials: L
authors.lastname: Capelozza Filho
authors.forename: Mauricio A
authors.initials: MA
authors.lastname: Cardoso
authors.forename: Danieli C R
authors.initials: DC
authors.lastname: Siqueira
authors.forename: Danilo F
authors.initials: DF
authors.lastname: Siqueira
mesh_terms: D015502:Absorptiometry, Photon; D015519:Bone Density / Q000528:radiation effects; D001861:Bone Regeneration / Q000528:radiation effects*; D002648:Child; D003393:Cranial Sutures / Q000528:radiation effects; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D054023:Lasers, Semiconductor / Q000627:therapeutic use; D028022:Low-Level Light Therapy / Q000379:methods*; D008297:Male; D008437:Maxilla / Q000000981:diagnostic imaging / Q000528:radiation effects; D016382:Orthodontic Appliance Design; D010155:Palatal Expansion Technique / Q000295:instrumentation; D021362:Palate, Hard / Q000528:radiation effects*; D011829:Radiation Dosage; D019252:Radiography, Dental, Digital / Q000379:methods