Geometric morphometric analysis of growth patterns among facial types

Abstract

Introduction: Extreme patterns of vertical facial divergence are of great importance to clinicians because of their association with dental malocclusion and functional problems of the orofacial complex. Understanding the growth patterns associated with vertical facial divergence is critical for clinicians to provide optimal treatment. This study evaluates and compares growth patterns from childhood to adulthood among 3 classifications of vertical facial divergence using longitudinal, lateral cephalograms from the Craniofacial Growth Consortium Study. Methods: Participants (183 females, 188 males) were classified into 1 of 3 facial types on the basis of their adult mandibular plane angle (MPA): hyperdivergent (MPA .39 ; n 5 40), normodivergent (28 # MPA # 39 ; n 5 216), and hypodivergent (MPA \28 ; n 5 115). Each individual had 5 cephalograms between ages 6 and 20 years. A set of 36 cephalometric landmarks were digitized on each cephalogram. Landmark configurations were superimposed to align 5 homologous landmarks of the anterior cranial base and scaled to unit centroid size. Growth trajectories were calculated using multivariate regression for each facial type and sex combination. Results: Divergent growth trajectories were identified among facial types, finding more similarities in normodivergent and hypodivergent growth patterns than either share with the hyperdivergent group. Through the use of geometric morphometric methods, new patterns of facial growth related to vertical facial divergence were identified. Hyperdivergent growth exhibits a downward rotation of the maxillomandibular complex relative to the anterior cranial base, in addition to the increased relative growth of the lower anterior face. Conversely, normodivergent and hypodivergent groups exhibit stable positioning of the maxilla relative to the anterior cranial base, with the forward rotation of the mandible. Furthermore, the hyperdivergent maxilla and mandible become relatively shorter and posteriorly positioned with age compared with the other groups. Conclusions: This study demonstrates how hyperdivergent growth, particularly restricted growth and positioning of the maxilla, results in a higher potential risk for Class II malocclusion. Future work will investigate growth patterns within each classification of facial divergence. (Am J Orthod Dentofacial Orthop 2021;-:---) C lassifications of facial and dental morphology are frequently used in orthodontic practice for diagnosis, treatment planning, and prognosis. Schudy 1 first characterized the interaction of vertical and anteroposterior growth in the face as patterns of facial divergence (ie, hyperdivergent, normodivergent, and hypodivergent), and since then, additional terminology has been used to describe similar morphologic patterns. The hyperdivergent skeletal pattern has been referred to as an open bite 2-4 or long face syndrome, [5][6][7] and the

Craniofacial growth and morphology among intersecting clinical categories

“…In this study, hyper‐divergent morphology is described by a longer upper anterior face and mandibular symphysis, shorter mandibular ramus, slightly shorter maxilla and mandible (in females), and a larger gonial angle in comparison to the control sample. The overall pattern of a tall anterior face and short posterior face results from growth that has been described as backward mandibular rotation (Björk & Skieller, 1983) and also characterized as a coordinated pattern of growth and rotation of the maxilla and mandible when oriented on the anterior cranial base (Knigge et al, 2021). Conversely, hypo‐divergent morphology is characterized by a shorter upper anterior face and mandibular symphysis, longer mandibular ramus, longer maxilla and mandible, and smaller gonial angle in comparison to the control group (Figure 18).…”

“…Conversely, hypo‐divergent morphology is characterized by a shorter upper anterior face and mandibular symphysis, longer mandibular ramus, longer maxilla and mandible, and smaller gonial angle in comparison to the control group (Figure 18). The overall pattern of a short anterior face and long posterior face results from growth described as excessive forward rotation and relative elongation of the mandible (Björk & Skieller, 1983; Knigge et al, 2021). Previous descriptions of growth patterns for each vertical classification group in this sample are provided by Knigge et al (2021).…”

“…Most studies comparing categories of vertical skeletal divergence identify differences in morphology among groups early in childhood, by approximately 5 or 6 years of age (e.g., Bishara & Jakobsen, 1985; Hardin et al, 2020; Moon et al, 2013; Nanda, 1988; Oh et al, 2019). Although Bishara and Jakobsen (1985) found parallel growth trajectories in dental and craniofacial cephalometrics among classification groups during adolescence, numerous other studies identified differences in adolescent craniofacial growth in relation to mandibular rotation (Björk, 1969; Björk & Skieller, 1983; Karlsen, 1995, 1997), vertical facial growth (Hardin et al, 2020; Jacob & Buschang, 2011), mandibular growth (Buschang et al, 2002; Oh et al, 2019), and the overall morphological pattern of the facial skeleton (Knigge et al, 2021).…”

The Relationship between Dentofacial Vertical Pattern and Bite Force Distribution among Children in Late Mixed Dentition

“…Children with gross facial asymmetry or deviation of the jaw on mouth opening were also excluded from the study. All included participants were categorized as having a short, average, and long face based on previously established criteria based on the Mandibular Plane Angle (MPA) (1)(2)(3). A search of the cephaplometric records of age appropriate children from the databases of three different tertiary care centers was undertaken to screen a total of 90 children (30 per group) having a short ((MPA < 28 • ), normal (28 • ≤ MPA ≤ 39 • ), and long (MPA > 39 • ) facial types.…”

“…When classified according to dentofacial vertical pattern there are three basic kinds of facial morphology: short, average, and long [1][2][3]. Many with a long face have excessive vertical facial growth that is generally associated with an open anterior bite, increased angle of sella-nasion (SN)/mandibular plane (MP), increased gonial angle, and increased angle of maxillary/mandibular planes [4].…”