ABSTRACT
Maxillary incisor retraction and associated upper lip changes were studied in 30 male and 30 female postadolescent orthodontic patients to determine if a statistically significant correlation and ratio existed between maxillary incisor and lip retraction, dependent on thickness, strain, and length of the upper lip. This analysis attempted to eliminate the effects of growth and gender. Statistically significant correlations were found in both male and female patients who had thin, highly strained lips. Although a ratio for predictive purposes was determined for each of these groups, their absolute value is questionable because no apparent pattern exists between them. Furthermore, as lip thickness increased and lip strain decreased, correlation coefficients fell to nonsignificance, making it more difficult to predict upper lip change resulting from maxillary incisor retraction in these individuals.
Subject(s)
Face/anatomy & histology , Incisor , Orthodontics, Corrective , Adult , Cephalometry/statistics & numerical data , Female , Humans , Lip/anatomy & histology , Male , Maxilla , Orthodontics, Corrective/statistics & numerical data , Random Allocation , Sex CharacteristicsABSTRACT
Extensive literature exists concerning impacted maxillary canines. Tooth-size/arch-size discrepancy (lack of space) is a common etiologic factor of impacted canines. No studies exist documenting transverse maxillary deficiency as a causative factor for impacted canines. The purpose of this study was to determine whether patients with impacted maxillary canines have transverse deficiency and if other factors, such as arch length, arch perimeter, and arch form contribute to canine impaction. Fifty-seven (57) subjects with eighty-one (81) impacted maxillary canines were compared to one hundred-three (103) nonimpacted subjects. Intermolar (IM) and intercanine (IC) width, arch length (AL), arch perimeter (AP), and arch form were recorded for each subject. The experimental and control groups were compared using a Z test and Chi-square analysis. Results indicate subjects with canine impactions demonstrate profound transverse maxillary deficiency located in the anterior portion of the dental arch: No significant difference in arch form is noted between the experimental and control groups (p > 0.05).
