The lower lip profile change during total distalization of the mandibular dentition

Abstract Objectives This study aimed to determine the factors that influence the lower lip profile during Class III lower total arch distalization camouflage treatment. Materials and 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 at the pre-treatment stage and post-treatment stage were taken. Cephalometric measurements were analyzed to uncover 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 conducted between variables. The formulas were 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) Conclusions The present study provided evidence that the lower lip evaluation including the novel CKA and CKHA, were significantly related to the mandibular incisal position during total distalization of the mandibular dentition. The results demonstrated that, clinically, significant lip retraction can be obtained. Therefore, non-extraction with distalization must be suggested as the first treatment option in mild skeletal Class III malocclusion patients.