Personalized Orthodontics: From the Sagittal Position of Lower Incisors to the Facial Profile Esthetics

Abstract

Background: One of the goals of orthodontic treatment is to obtain maximum facial harmony. The sagittal position of the lower incisors plays a significant role in the planning of orthodontic treatment. The aim of the study was to evaluate the relationship between the sagittal position of lower incisors and facial profile esthetics with reference to the skeletal vertical dimension. Methods: There were 200 patients included in the study. Patients were allocated into three groups, depending on the vertical growth pattern: normal-angle, low-angle, and high-angle cases. Tweed–Merrifield cephalometric analysis was used to assess the sagittal and vertical position of the mandible, as well as to assess the sagittal position of the lower incisors. Results: Z-angle and Frankfort mandibular incisor plane angle (FMIA) decreased significantly (p < 0.001) with the increase of the skeletal vertical dimension. Incisor mandibular plane angle (IMPA) was significantly higher (p < 0.001) in low-angle patients compared to the high-angle ones. Z-angle appeared to be the most accurate parameter (area under curve, AUC = 0.957) describing patients with a convex profile. The cutoff value of Z-angle 68.0° was characterized by the sensitivity of 94.1% and the specificity of 84.3%. Conclusions: The sagittal position of the lower incisors significantly affects the facial profile convexity. The Z-angle is the parameter which most accurately describes the patients with a convex profile.

Comparison of Diagnostic Validity of Cephalometric Analyses of the ANB Angle and Tau Angle for Assessment of the Sagittal Relationship of Jaw and Mandible

“…Regarding errors associated with the identification of anthropometric points [10,12,[16][17][18][19][20][21][22], the majority of studies that have evaluated the reproducibility and reliability [1,3,10,12,[20][21][22][23][24][25][26] of individual landmarks have reported errors in point identification. Accurate assessment and repeatability are particularly crucial in growing patients, especially when dealing with the imprecise determination of points A, N, and B.…”

The Correlation of a Novel Photographic Parameter for Facial Profile Assessment in Subjects With Different Sagittal Malocclusions: A Prospective Study

“…The Z and Holdaway angles were chosen for assessing the soft tissue maxillomandibular discrepancy. Both these angles were chosen because they are widely used for soft tissue profile analysis [ 27 ]. A strong correlation was noted between the FSA angle and Z angle in Class I (r-value = 0.836), Class II (r-value = 0.821), and Class III malocclusion subjects (r-value = 0.904; Table 3 ).…”

“…A strong correlation was noted between the FSA angle and Z angle in Class I (r-value = 0.836), Class II (r-value = 0.821), and Class III malocclusion subjects (r-value = 0.904; Table 3 ). A previous study by Derwich et al reported that the Z angle could be used as an accurate diagnostic parameter to assess the convexity of the facial profile [ 27 ]. Contini et al reported that the Z angle could reliably assess facial convexity in different malocclusions with various growth patterns [ 28 ].…”

Non-extraction camouflage treatment using extra-alveolar skeletal anchorage

“…29 The sagittal position of the mandibular incisors is considered to be an essential determinant of facial aesthetics and stability. [30][31][32] Tweed 30 advocated placing the mandibular incisors in an upright position over the basal bone to achieve optimum results.…”