Maxillary expansion with the memory screw: a preliminary investigation
Open Access
- 1 January 2012
- journal article
- Published by Korean Association of Orthodontists in The Korean Journal of Orthodontics
- Vol. 42 (2), 73-79
- https://doi.org/10.4041/kjod.2012.42.2.73
Abstract
The purpose of this study was to investigate the effects of a newly developed rapid maxillary expansion screw-the memory screw-over 6 months. Five subjects, aged between 11.7 and 13.75 years, were enrolled in this study. All subjects underwent placement of a maxillary expansion appliance containing superelastic nickel-titanium open-coil springs in its screw bed. The parents of the patients and/or the patients themselves were instructed to activate the expansion screw by 2 quarter-turns 3 times a day (morning, midday, and evening; 6 quarter-turns a day). The mean expansion period was 7.52 ± 1.04 days. Dentoskeletal effects of the procedure, including dentoalveolar inclination, were evaluated. Measurements of all the parameters were repeated after 6 months of retention in order to check for relapse. Sella-Nasion-A point (SNA) and Sella-Nasion/Gonion-Menton angles increased, and Sella-Nasion-B point (SNB) angle decreased in all the subjects during the expansion phase. However, they approximated to the initial values at the end of 6 months. On the other hand, the increments in maxillary apical base (Mxr-Mxl) and intermolar widths was quite stable. As expected, some amount of dentoalveolar tipping was observed. The newly developed memory expansion screw offers advantages of both rapid and slow expansion procedures. It widens the midpalatal suture and expands the maxilla with relatively lighter forces and within a short time. In addition, the resultant increments in the maxillary apical base and intermolar width remained quite stable even after 6 months of retention.Keywords
This publication has 19 references indexed in Scilit:
- A comparison of dentoalveolar inclination treated by two palatal expandersEuropean Journal of Orthodontics, 2007
- Evaluation of the inclination in posterior dentoalveolar structures after rapid maxillary expansion: a new methodDento maxillo facial radiology, 2007
- Longitudinal study and cost-benefit analysis of the effect of early treatment of posterior cross-bites in the primary dentitionEuropean Journal of Orthodontics, 1992
- Skeletal changes in vertical and anterior displacement of the maxilla with bonded rapid palatal expansion appliancesAmerican Journal of Orthodontics and Dentofacial Orthopedics, 1989
- Midpalatal suture opening during functional posterior cross-bite correctionAmerican Journal of Orthodontics, 1978
- Slow maxillary expansionAmerican Journal of Orthodontics, 1978
- Rapid correction of Class III malocclusion by midpalatal expansionAmerican Journal of Orthodontics, 1973
- Skeletal and dental changes accompanying rapid midpalatal suture openingAmerican Journal of Orthodontics, 1970
- Palatal expansion: Just the beginning of dentofacial orthopedicsAmerican Journal of Orthodontics, 1970
- Expansion of the Midpalatal Suture, Studied by Means of Metallic ImplantsActa Odontologica Scandinavica, 1959