Protraction Effect of Rampa on Maxillae, Upper Airway and Hyoid Bone Position; Finite Element Analysis

Bumkyoo Choi*¹, Jaehyuk Choi¹, Hyeong-un Kim², Seok-soon Yi², Yeon-mi Yang² and Yasushi Mitani³

Received: January 19, 2018;   Published: January 31, 2018

DOI: 10.26717/BJSTR.2018.02.000707

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Abstract

Purpose: This paper presents the effectiveness of RAMPA (Right Angle Maxillary Protraction Appliance) system, i.e. RAMPA combined with ROA (RAMPA Oral Appliance), on human maxillae by analyzing the deformations from protraction forces with finite element method. In addition, the dimensional changes of the upper airway, skeletal facial and hyoid position changes by using cone-beam computed tomography in patients who were treated with RAMPA therapy were assessed clinically.

Methods: Using the integrated modeling that combines the 3D Scan file of the skull model with RAMPA structures designed in SolidworksTM, the amount of displacements has been calculated and the effect of RAMPA on the human skull has been analyzed quantitatively. The three types of forces were applied and the displacements were calculated and analyzed. For 6 patients with a mean age of 8.3 years (range, 7~10 years) who were treated with RAMPA therapy, CBCTs were taken before and after treatments and the images were measured by InViv TM (Anatomage) software, and analyzed.

Results: RAMPA rotates the patient’s maxilla and mandible in the forward direction and forces them to move upward. After RAMPA treatments, there were significant increase of retroglossal and total airway volume (P<0.05). The horizontal. DH and C3-H, which indicate the anterior position of the hyoid bone, were increased and HyS and vert. DH, which represent the vertical facial dimension, was decreased after treatment.

Key words: RAMPA; Protraction; FEM; Airway; Hyoid Bone

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