The Effects of Maxillary Quad-Helix Appliance Expansion on Cephalometric Measurements in Growing Orthodontic Patients

<p>This study was conducted to examine the effects of maxillary quad-helix expansion on frontal and lateral cephalometric measurements in growing orthodontic patients. Twenty subjects, nine girls and eleven boys (x age = 10 years, 3 months), each exhibiting at least a unilateral posterior lingual cross-bite that had been treated with a maxillary quad-helix appliance, were selected for this study. Posterior-anterior and lateral cephalometric radio graphs were taken at the beginning of treatment (T₁), when the appliance was removed (T_prog' x time = nine months) and at retention (T₂) and subsequently traced. The T₁ and T₂dental casts were also measured as supplement to the cephalometric measurements. Significant orthodontic changes, as seen on the frontal radiographs from T₁ to T_prog'included a mean increase in maxillary intermolar width of 5.88 mm, a mean increase in average frontal molar relation of 2.95 mm and a mean increase in maxillary intercanine width of 2.74 mm. The orthopedic changes, as evidenced radiographically, included a mean increase in maxillary width of .92 mm and an increase in average maxillomandihular width of .89 mm. From the above data a 6;1 ratio of orthodontic movement to orthopedic movement was deter mined. No significant change in mandibular intermolar width was observed from the cephalometric data or the cast measurements. The most stable cases after expansion presented with normal nasal widths and narrow maxillary widths. No correlation was shown between the age of the patients and the orthopedic expansion recorded, or the amount of orthodontic/orthopedic expansion and facial type. It was concluded that all expansion changes showed little relapse from T_prog to T₂, and that moderate orthopedic expansion is possible with the quad-helix, but only slight orthopedic expansion was consistently demonstrated.</p>

Name thesis:degree_name

Master of Science (MS)

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Dentistry

Year

1981

Author dc:creator

• Frank, Steven Wesley

Contributors dc:contributor

• J. Milford Anholm
• Roland D. Walters
• Lawrence W. Will
• Willis L. Schlenker
• Robert M. Ricketts
• Lee E. Olsen
• Gary G. Morikone

• Orthodontics and Orthodontology
• Orthodontic Appliances

Statement dc:rights

• This title appears here courtesy of the author, who has granted Loma Linda University a limited, non-exclusive right to make this publication available to the public. The author retains all other copyrights.

Language dc:language

English

Repository record dc:identifier

https://scholarsrepository.llu.edu/etd/1332

OAI identifier oai:identifier

oai:scholarsrepository.llu.edu:etd-2789