Thesis
Maxillary transverse expansion: a study of dentoalveolar effects with TAD-supported RMEs versus traditional RMEs
University of Iowa
Master of Science (MS), University of Iowa
Spring 2021
DOI: 10.17077/etd.006115
Abstract
Introduction: Maxillary transverse discrepancies are commonly treated with a rapid maxillary expander (RME) with the intention of obtaining skeletal expansion to widen the maxilla. However, as patients become older/skeletally mature, obtaining successful suture separation becomes less likely. This could lead to a potential surgery to correct the transverse discrepancy. Temporary anchorage devices (TADs)/mini-screws/micro-implants) are becoming more popular and are being incorporated into the appliance designs of RMEs in order to increase the skeletal anchorage. Research has shown these TAD-supported RMEs, which may also be called MARPEs (mini-screw assisted rapid palatal expanders), MARMEs (mini-screw assisted rapid maxillary expanders), or MSEs (maxillary skeletal expanders), can be an effective option for achieving skeletal expansion for patients who are older/more skeletally mature. There are a variety of appliance designs (tooth-borne, tooth-bone borne, and bone-borne) as well as variations within the specific designs of each appliance. The purpose of this study was to evaluate the dentoalveolar effects of traditional RMEs versus TAD-supported RMEs.
Methods:
48 subjects who were treated with rapid maxillary expansion and had a successful split of the midpalatal suture (MPS) were included. They were treated at the University of Iowa Orthodontic Department. 19 subjects were treated with a TAD-supported RME and 29 were treated with a traditional (2-banded) RME. Pre- and post-expansion measurements including arch perimeter, tooth size, intercanine width, intermolar width, arch length, inclination of alveolus, and inclination of molar were made on maxillary digital models. Crowding was determined by calculating the difference of arch perimeter and the sum of the mesial-distal tooth widths (arch perimeter-tooth size).
Results:
When comparing differences in pre- and post-expansion measurements in subjects with traditional RMEs, mean arch length, absolute mean crowding, and mean inclination of molars were significantly higher at pre-expansion. The mean arch perimeter, mean tooth size, mean intercanine width, mean intermolar width, and mean inclination of alveolus were significantly higher at post-expansion. The same categorical findings were found in pre- and post-expansion measurements in subjects with TAD-supported RMEs. When comparing the change in pre- and post-expansion measurements between subjects with traditional RMEs and TAD-supported RMEs, no statistically significant differences between the two groups were found for mean changes in arch perimeter, tooth size, crowding, intermolar width, inclination of alveolus, and inclination of molars. However, the mean change (increase) in intercanine width in the TAD-supported RME group was significantly higher than in the traditional RME group. In addition, the mean absolute change in arch length (a larger decrease in arch length) was significantly higher in the TAD-supported RME group.
Conclusion:
Both traditional and TAD-supported RMEs can lead to significant changes during expansion. We found TAD-supported RMEs to have a greater increase in intercanine width and a larger decrease in arch length versus traditional RMEs. This should be carefully interpreted as there are many variables involved that could contribute to this conclusion.
Details
- Title: Subtitle
- Maxillary transverse expansion: a study of dentoalveolar effects with TAD-supported RMEs versus traditional RMEs
- Creators
- Samantha Jayne Marti
- Contributors
- Kyungsup Shin (Advisor)Steven Marshall (Committee Member)Thomas Southard (Committee Member)Shankar Venugopalan (Committee Member)Fang Qian (Committee Member)
- Resource Type
- Thesis
- Degree Awarded
- Master of Science (MS), University of Iowa
- Degree in
- Orthodontics
- Date degree season
- Spring 2021
- DOI
- 10.17077/etd.006115
- Publisher
- University of Iowa
- Number of pages
- xi, 77 pages
- Copyright
- Copyright 2021 Samantha Jayne Marti
- Language
- English
- Description illustrations
- color illustrations
- Description bibliographic
- Includes bibliographical references (pages 70-73).
- Public Abstract (ETD)
Having a narrow upper jaw can cause a crossbite of the back teeth and crowding. It may also lead to a shift of the lower jaw and asymmetric growth. A common way to correct this narrow jaw is an expander that widens the upper jaw. These are more effective in children and as age increases/the patient become more skeletally mature, it becomes harder for these expanders to work. To try and make these work for older/more mature patients, mini-screws are being added to the expander to help achieve successful widening. For this study, various measurements were taken on before and after models from patients who had a traditional expander or an expander with mini-screws to see if there were differences in tooth/tooth socket movements with the different expanders. Using both types of expanders led to significant tooth/tooth socket movements. When comparing the two types, we found a larger increase in width between the teeth closer to the front of the mouth with the mini-screw expanders. There are many variables involved that could have contributed to this.
- Academic Unit
- Orthodontics; Craniofacial Anomalies Research Center
- Record Identifier
- 9984097479002771
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