This study aimed to investigate the hard tissue and soft tissue characteristics related to favorable facial attractiveness outcomes of Class II Twin-block treatment to select suitable patients for this therapy.

A total of 86 skeletal Class II patients who had undergone Twin-block treatment were included in this study. Post-treatment facial attractiveness was assessed by seven orthodontists using visual analog scale (VAS) scores based on 3D photographs. Patients were ranked according to their VAS scores, with the top 26 individuals classified as the favorable group and the bottom 26 as the unfavorable group. Soft tissue and hard tissue measurements were obtained from their 3D photos and lateral cephalograms, and intergroup comparisons were conducted using the independent t-test and Mann-Whitney test.

The favorable group exhibited significantly lower values for Co-pog, FH-MP, L1-APog, Li-H Line, and Total Convexity Angle before treatment, according to independent t-tests and Mann-Whitney tests. Conversely, the favorable group demonstrated significantly higher values for the Wits appraisal, Pog-NB, S-Go/N-Me, Si-H and Ch_R-Li-Ch_L were larger(P < 0.05).

Patients with low divergent skeletal patterns, a well-developed chin, upright lower incisors, a flat lower lip, and a large amount of skeletal discrepancy between the maxillary and the mandibular are likelier to achieve favorable facial attractiveness outcomes following Twin-block treatment.