The Lower Lip Profile Change During Total Distalization of the Mandibular Dentition

Abstract

Objectives: This study aimed to determine the factors influencing the lower lip profile during Class III lower total arch distalization camouflage treatment. Methods: The cohort included 45 patients diagnosed with skeletal class III malocclusion. These patients underwent camouflage orthodontic treatment with lower arch total distalization. Lateral cephalograms were taken at the pretreatment and posttreatment stages. Cephalometric measurements were analyzed to unravel the influencing factors of the lower lip profile. This study defined new variables, i.e., CK and CKA, for detailed soft tissue analysis. Results: Novel soft tissue measurements presented in this study showed statistically significant changes after treatment. The CK angle and L1 to A Pog, L1 to NB, and IMPA were statistically correlated. Simple regression analysis was performed between variables. The formula was ΔCKA = 0.79(Δ L1 to NB)-1.6, and multiple regression resulted in ΔCKA = 0.5(Δ L1 to NB) – 0.42 (‘LL to Eline’, before treatment). Conclusion: The present study provided evidence that the lower lip evaluations, including the novel CKA and CKHA, were significantly related to the mandibular incisor position during total distalization of the mandibular dentition. The results demonstrated that clinically significant lip retraction could be obtained. Therefore, non-extraction with distalization must be suggested as the first treatment option in mild skeletal class III malocclusion patients.