الفهرس 
AcknowledgementOnly 14 pages are availabe for public view
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Abstract
Objectives: This randomized clinical trial was conducted to evaluate clinically and radiographically the efficacy of the Low-Level Laser Therapy (LLLT) using bone-borne hyrax expander on the amount of expansion in growing patients with transverse maxillary deficiency.
1. Materials and Methods: Twenty-four female patients of age range 10-13 years with transverse maxillary deficiency were enrolled in this study. The patients were divided into two groups: group I: consisted of 12 patients that received bone-borne palatal expansion without laser, and group II: consisted of 12 patients that received bone-borne palatal expansion along with LLLT. Cone-beam computed tomography, dental cast and inta- and extra- oral photographs were obtained before treatment (T0), and six months after the retention phase (T2). A mini-screw supported maxillary expander was used for expansion by 4 turns for initial activation followed by twice a day activation for the rest of the expansion phase (15 days). The laser group received LLLT using Biolase (Epic 10 Console) with active medium InGaAs (Indium gallium arsenide) Semi-conductor diode via the tooth whitening tip (Rectangular 35mm x 8 mm = 2.8cm2) according to the manufacturer instructions by using the following parameters: Wavelength: 780 nm, Power density: 40 mW, Energy density: 10J/cm2, Energy per point: 32 J, Continuous wave, Time: 8 seconds. Application was done in points, distributed in 4 application areas around the mid-palatal suture: Two anterior areas from jackscrew to the canines and two posterior areas from the jackscrew to the first molars. The laser was applied on the first 5 days of the expansion phase and after that on the first three days of the retention phase after locking the hyrax screw. The next three doses were delivered with 7 days apart during the retention phase. Diastema, inter-canine, inter-premolar, and inter-molar width was measured clinically during the expansion phase to measure the rate of palatal expansion. A Wong Baker Faces Scale was used to measure the amount of pain the patient experienced during the expansion phase. After full activation, the appliance was locked using composite on the screw to start the retention phase. The appliance was left for the 6 months of retention. After the records obtained at (T2), skeletal and dental measurements were obtained to study the effect of LLLT on bone-borne palatal expansion retention. Results: The maxillary width and nasal width were significantly increased in both laser and none-laser groups with a greater stability of the measurements after LLLT. The total facial heights were significantly increased similarly in both laser and none-laser group. The laser group revealed a significant increase in the SNA and ANB angles as a result of forward maxillary displacement. However, no significant changes were reported within the none-laser group. A significant increase in the apical inter-incisor width was found only in the laser group. This was an indicator that LLLT treatment had a sufficient effect on increasing the retention of the palatal expansion and maintaining the expansion in the anterior portion of the mid-palatal suture. Regarding the rate of expansion, there was a significant increase in the inter-canine and inter-premolar rate of expansion on the first and third days in the laser group due to the initial effect of LLLT in the active expansion phase. Low level laser therapy had no effect on the level of pain during palatal expansion. The patients experienced mild pressure and discomfort on the alveolar region on the first 3 days and by the end of the expansion phase every time the screw was activated. Conclusion: LLLT was found to have a significant effect on the dental and skeletal stability after 6 months of retention. Regarding the rate of expansion, there was a significant increase in the inter-canine and inter-premolar rate of expansion on the first and third days in the laser group due to the initial effect of LLLT in the active expansion phase. LLLT had no effect on the level of pain during palatal expansion.