Xin yixue (Jan 2023)
Comparative analysis of chin morphological characteristics of different vertical facial types in patients with congenital absence of lower incisors
Abstract
Objective To investigate the morphological characteristics of the chin in patients with congenital absence of lower incisors with different vertical facial types， and to explore their differences with the normal population. Methods 120 female adolescent patients were stratified randomly selected as the study subjects. Among them， 60 cases of congenital loss of a lower incisor were assigned into the experimental group， and 60 cases without tooth loss were allocated into the control group. There were 20 cases of high angle， average angle and low angle in each group. All patients took lateral cephalometric films. The measurement results were statistically analyzed. Results The height and curvature of the chin from large to small were high angle group， average angle group and low angle group （all P < 0.05）. The maximum chin height in the experimental group was （21.20±1.32） mm， the minimum chin height was （16.91±1.57） mm. In the control group， the maximum chin height was （23.96±1.04） mm， and the minimum chin height was （19.70±1.66） mm. The chin angle in the high angle group was smaller than that in the low angle group（both P < 0.05）. In the experimental group， the ANB， Y-axis and chin curvature were significantly larger （all P < 0.05）， while SNB， chin height， chin thickness， minimum chin thickness， posterior chin thickness and chin angle were significantly smaller compared with those in the control group （all P < 0.05）. Conclusions The chin morphology is different among patients with different vertical facial types. The chin morphology of patients with congenital loss of the lower incisors is different from that of normal population. In orthodontic treatment， extensive attention should be paid to the chin morphology of patients with congenital loss of lower incisors， thereby designing a reasonable treatment regimen.
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