Crowding, Tooth

The periodontal phenotype influences treatment outcomes across dental specialties, as tissues of different thickness respond differently to chemical, bacterial, and mechanical insults. In pediatric patients, understanding the gingival phenotype is particularly relevant: a thin phenotype may predispose to dehiscence, fenestration, and gingival recession-especially at the mandibular incisors-when tooth movement exceeds the biological limits of the bony housing. During the mixed dentition phase, significant changes in soft and hard tissues affect tooth position and periodontal stability, making early phenotype assessment essential. Interceptive orthodontics can reduce the long-term risk of mucogingival defects; early identification of a thin biotype allows for preventive strategies, including soft tissue grafting before critical orthodontic movements. No studies have examined the association between dental crowding severity and periodontal phenotype in children. Adult data remain inconsistent: Kaya et al. found no correlation between phenotype and skeletal malocclusion, while Kong et al. reported a site-specific association between thin biotype and skeletal Class I/III at the mandibular central incisor. No predictive model exists for periodontal risk related to severe crowding in childhood. This study aims to assess the periodontal phenotype in pediatric patients across different stages of dental transition and to investigate a possible association between a thin periodontal biotype and severe dental crowding.

The purpose of this study is to evaluate the biomechanical behaviour of direct-printed and thermoformed aligners in different tooth movements, creating a biomechanical planning protocol based on a stratification of tooth movements according to the degree of predictability.