Facial growth pattern: Association between lower incisor position and symphyseal morphology

Abstract

BackgroundA key factor in planning orthodontic treatment is the position of the lower incisor, which must keep a correct relationship with its underlying bony support, the mandibular symphysis. ObjectivesTo determine whether there is a statistically significant relationship among the position of the lower incisor, Holdaway ratio, symphyseal morphology, and facial pattern. MethodsA total of 100 patients were randomly selected from the records of the Master in Orthodontics and Dentofacial Orthopedics (University of Seville, Spain). Measurements were made manually on pretreatment cephalograms by two operators using Aki analysis to assess the height/width ratio (H/A), mandibular plane with point B–Menton, and the retro-occlusion of the Jarabak/MSE analysis to determine the facial biotype. A descriptive analysis of the data was made evaluating the possible correlations between the Holdaway ratio and H/A, and the Holdaway ratio and mandibular angle. ResultsThe correlation among facial pattern, H/A, and the Holdaway ratio proved significant (P < 0.05). ConclusionsSymphyseal morphology is correlated to facial growth pattern and lower incisal inclination. There are biological limits to inclination movements of the lower incisor in narrow symphysis, which are usually found in vertical growth patterns.