Distribution of the Condylion-Gonion-Menton (CoGoMe^) Angle in a Population of Patients from Southern Italy

Abstract

The condylion-gonion-menton angle (CoGoMe^) is commonly used as a pre-treatment indicator of responsiveness in Class II patients treated with functional appliances. The distribution of this angle in the Caucasian population is still unknown. This study aimed to determine the distribution of the CoGoMe^ and its relationship with age, sagittal jaw relationship (ANPg^), and mandibular inclination (SN^GoGn) in patients from Southern Italy. The sample included 290 subjects (median14 years of age; Interquartile range, IQR, 12–17) with lateral cephalograms taken before the orthodontic treatment. The distribution of the CoGoMe^ was assessed with the Shapiro–Wilk test, and the differences according to the ANPg^ and the SN^GoGn were estimated using one-way ANOVA. Linear regression analysis was performed to evaluate how the CoGoMe^ varied according to age. The statistical significance was set at P < 0.05. The results showed that the CoGoMe^ was normally distributed (P = 0.290) with a mean value of 127.2° ± 7.7°. The distribution of the CoGoMe^ in groups with different SN^GoGn angles was significantly different (P < 0.001). These angles showed a positive association (Beta coefficient B = 0.6; 95% CI: 0.51, 0.67; P < 0.001). In growing patients, the CoGoMe^ decreased every year by 0.6° (B = −0.6; 95% CI: −1.05, −0.12; P = 0.014). In conclusion, the CoGoMe^ was associated with mandibular inclination and could be considered to be a predictor of vertical growth patterns.

Does Mandibular Gonial Angle Influence the Eruption Pattern of the Lower Third Molar? A Three-Dimensional Study

“…As reported in literature, the gonial angle is closely related to the growth pattern and facial typology [ 18 , 28 , 29 ]. According to D’Antò (et al), the GA could help to define the mandibular rotational pattern with more accurate information than the angle between anterior cranial base and mandibular plane that is influenced by the anterior cranial base inclination [ 30 , 31 ]. Dolichofacial people showed a clockwise mandibular growth pattern and an increased anterior facial height, with high values of the GA; on the contrary, in brachyfacial individuals a counter-clockwise mandibular rotation, a decreased anterior facial height, and a lower GA were recorded [ 18 ].…”

“…Because D’Antò and colleagues found a strong positive association between the GA and the angle between anterior cranial base and mandibular plane, we can conclude that the counter-clockwise mandibular growth could predispose to the deepest position of the M3M that should take a more complex eruptive path in mandibles with an acute gonial angle [ 30 ]. In the L-GA group, the disadvantages of a hypodivergent growth pattern could interfere with the angulation of the M3M impaction, predisposing to a complete or partial M3M impaction.…”

“…Mandibular morphology has a central role in the overall facial growth and the gonial angle characterizes, specifically the growth pattern of the mandible, influencing its vertical development [ 5 , 28 , 36 , 37 ]. The direction of mandibular growth is related with a hyperdivergent or hypodivergent facial typology, showing high or low gonial angle, respectively [ 30 , 36 , 38 ]. As described in literature, the different clinical characteristics of these two mandibular patterns of growth concern also the position and the eruptive path of the M3M [ 16 , 17 , 18 , 19 , 20 ].…”

“…However, the study design as a single-center study is limited. The southern Italian population frequently includes people with counter-clockwise mandibular rotation that could influence the cut-off value for the H-GA and the L-GA groups [ 30 ].…”

Relationship between the Condylion–Gonion–Menton Angle and Dentoalveolar Heights

“…As discovered by Franchi et al, the Condylion-Gonion-Menton angle (CoGoMeˆ) is able to recognize and distinguish the responsiveness of patients to Class II functional treatment [31]. A recent investigation of the CoGoMeˆin a population of patients from southern Italy found that it was associated with mandibular divergency and can be considered a predictor of vertical growth patterns, with a mean value for normodivergent patients of 127.1 ± 6.1 [32]. Studying the relationship between this angle and the vertical characteristics of the dentoalveolar bone may offer orthodontists a valid cephalometric instrument for predicting a patient's growth and improving the treatment quality and prognosis.…”