Correction of Transverse Discrepancy with Slowly Maxillary Expansion by Hyrax type expander in Adult Patient

Kwak,  Kyoung Ho; Kim,  Seong Sik; Kim,  Yong-Il; Park,  Soo-Byung; Son,  Woo-Sung

J Korean Dent Assoc > Volume 55(6); 2017 > Article

The Journal of The Korean Dental Association 2017;55(6):400-410.
Published online June 30, 2017.

성인에서 Hyrax 장치로 완속상악확장하여 폭경부조화를 개선한 증례

곽경호¹, 김성식², 김용일³, 박수병⁴, 손우성⁵

^¹부산대학교 치의학전문대학원 치과교정학교실
^²부산대학교 치의학전문대학원 치과교정학교실
^³부산대학교 치의학전문대학원 치과교정학교실
^⁴부산대학교 치의학전문대학원 치과교정학교실
^⁵부산대학교 치의학전문대학원 치과교정학교실

Correction of Transverse Discrepancy with Slowly Maxillary Expansion by Hyrax type expander in Adult Patient

Kyoung Ho Kwak¹, Seong Sik Kim², Yong-Il Kim³, Soo-Byung Park⁴, Woo-Sung Son⁵

¹Department of Orthodontics, School of Dentistry, Pusan National University
²Department of Orthodontics, School of Dentistry, Pusan National University
³Department of Orthodontics, School of Dentistry, Pusan National University
⁴Department of Orthodontics, School of Dentistry, Pusan National University
⁵Department of Orthodontics, School of Dentistry, Pusan National University

Abstract

Approximately 30% of adult patients who want orthodontic treatment have transverse discrepancy with insufficient width of the maxilla. Particularly, in Class III patients requiring orthognathic surgery, the frequency of insufficient width of the maxillary arch related to respiratory problems is high. We report a case of non-surgical maxillary expansion using a Hyrax type expander with an orthognathic surgery, based on the reports that the ratio of non-fused midpalatal suture is not high in adults. A 30 years and 2 months old woman with a long face showed an Angle Class III with a vertical growth pattern. Class III molar and canine relation, anterior edge bite, and mandibular incisor compensatory lingual inclination were observed. The posterior buccal overjet seemed to be appropriate, but I diagnosed that there was a transverse discrepancy, for the following reasons. The inter-canine and inter-molar widths were sufficient but excessive lingual inclination of the mandibular molars was observed when assessing the bucco-lingual inclination based on the center of resistance of the maxillary and mandibular first molar. For this reason, it was expected that intercuspal interference would occur during orthodontic decompensation. Therefore, slow maxillary expansion using Hyrax type expander was performed and 2-jaw rotation surgery was performed to improve aesthetic and occlusion. Adults can also improve width discrepancy by non-surgical methods, which can avoid SARPE requiring additional surgery or segmental surgery lacking stability and predictability.

Key Words: Maxillary expansion;Hyrax;Adult;