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Title: The influence of rapid maxillary expansion on craniocervical angulations one year after treatment
Author: McGuinness, Niall John Patrick
Awarding Body: University of Edinburgh
Current Institution: University of Edinburgh
Date of Award: 2005
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Rapid maxillary expansion (RME) has been shown to increase nasal permeability and reduce nasal airway resistance. A sample of 42 adolescent patients with a narrow upper dental arch and unilateral or bilateral crossbite in the permanent dentition underwent RME as part of normal orthodontic treatment. Cephalograms in natural head position were taken before, immediately after, and one year after RME. No significant changes in the craniofacial angles were found immediately after expansion. One year post-expansion, however, NSL/VER had reduced by 3.14°, (p<0.01), indicating a drop in head position, while OPT/HOR reduced by 2.13° (p<0.05), and CVT/HOR had reduced by 2.55° (p<0.05), indicating a more forward inclination of the cervical spine. The results of this study suggest that when the nasal airway resistance decreases as a result of RME, this causes an initial slight increase in pharyngeal airway resistance. This is due to the increased nasal airflow, which results in a more forward inclination of the cervical spine in order to increase the cross-sectional area of the pharynx. This in turn reduces the pharyngeal airway resistance and results in an ongoing change in head posture due to alteration in the mode of breathing as a result of RME, thereby contributing to a change in craniofacial development, according to the soft-tissue stretching hypothesis of Solow and Krieborg (1977). This work adds to this hypothesis, and a supplementary hypothesis is proposed to augment the theory of Solow and Krieborg: it is that total airway resistance can be compartmentalised into nasal and pharyngeal portions, and that the two are in a state of dynamic equilibrium with each other and the factors controlling the relationship between head + posture, airway adequacy, and craniofacial morphology.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (D.D.S.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available