Craniofacial growth of Class III subjects six to sixteen years of age

Abstract

Objective: To characterize the mixed-longitudinal craniofacial growth of untreated, white, Class III subjects 6 to 16 years of age. Materials and Methods: Serial cephalograms of 19 females and 23 males with Class III malocclusion were evaluated at three time points (6-8, 10-12, and 14-16 years of age). A similar number of Class I controls were randomly selected and matched for age and sex. The cephalograms were traced and digitized, and 20 variables were evaluated. Growth patterns were quantified, and class and sex differences were evaluated using multi-level analyses. Results: In comparison with Class I subjects, Class III subjects had significantly (P # .05) larger mandibular plane angles, gonial angles, mandibular ramus heights, mandibular corpus lengths, and SNB angles, with differences that were maintained between 6 and 16 years of age. Maxillary lengths and ANB angles were significantly smaller and remained smaller in Class III subjects than in Class I subjects. Lower face height, maxillary-mandibular differential, and mandibular body length were also significantly larger and increased significantly more between 6 and 16 years of age in Class III subjects. The WITS appraisal was significantly smaller in Class III subjects and decreased significantly more over time. Most linear measures showed significant sex differences favoring males; the angular measures and anteroposterior (AP) maxillomandibular relationships showed no sex differences. Conclusions: The AP maxillomandibular relationship of Class III subjects worsens over time. AP discrepancies are primarily due to excessive mandibular growth, which produces a protrusive, hyperdivergent phenotype. The AP discrepancies of males are larger than those of females, with differences increasing over time. (Angle Orthod. 2011;81:211-216.)

Effect of face mask therapy on mandibular rotation considering initial and final vertical growth pattern: A longitudinal study

“…By the end of the treatment, the majority of patients maintained their initial vertical growth pattern, showing some changes in growth direction, mainly in those with neutral rotation. Of the former, some patients shifted toward having clockwise growth direction, whereas others had counterclockwise growth direction; suggesting that in response to therapy, changes toward clockwise mandibular rotations should not always be expected, as previously reported by others (Kiliçoglu & Kirliç, ; Nevzatoğlu & Küçükkeleş, ; Wolfe et al, ).…”

“…This type of skeletal relationship represents one of the most challenging issues faced by the orthodontic clinician due to the unpredictable and potentially unfavorable vertical growth pattern that these patients may exhibit (Kim, Viana, Graber, Omerza, & BeGole, ; Zhang et al, ). Wolfe et al reported that, compared with a Class I control group, patients with Class III malocclusion display hyperdivergent jaws and increased inferior facial height (Wolfe, Araujo, Behrents, & Buschang, ). Treatment has been aimed at maxillary advancement and/or control of jaw growth, and several devices have been designed for this purpose such as protraction face masks (FMs), chincups, mandibular cervical hedgear, and functional orthopedic appliances (Baccetti, Rey, Angel, Oberti, & McNamara, ; Baccetti, Rey, Oberti, Stahl, & McNamara, ; Baik, Jee, Lee, & Oh, ; Rey, Angel, Oberti, & Baccetti, ; Zhang et al, ).…”

Mandibular symphysis morphology and dimensions in different anteroposterior jaw relationships

“…22 The linear distances and angular measurement that expressed the vertical dimension of MS and the area of MS were largest in the Class III group compared to the Class I and Class II groups. Several studies [22][23][24] reported a larger mandible in the Class III relationship, including its symphysis, than in the other AP relationships.…”

The use of functional appliances in the correction of Class III malocclusion

“…5 Clearly, children and adolescents with Class III malocclusion do not have a typical skeletal phenotype. 8,9 This growth can also occur late in adolescence or even in early adulthood, particularly in relation to mandibular prognathism. Unlike Class II malocclusions, which tend to improve skeletally with growth, a Class III malocclusion if allowed to develop will become worse with age, with the growth of the mandible exceeding the growth of the maxilla.…”