Protraction of bilateral mandibular molars into the first molar extraction sites using long arm hooks with clear aligners of an adult Class II Division 2 with crowding: A case report.

Protraction of mandibular bilateral second molars to substitute for the extracted first molars is challenging in clear aligner treatment due to biological and biomechanical limitations. This case report presents a 28-year old female patient with poor prognoses for the mandibular bilateral first molars, a mesially impacted mandibular left third molar, and crowding in both the upper and lower arches. After the extraction of mandibular bilateral first molars, long-distance mandibular molar protraction was achieved using clear aligners with a novel protraction appliance, "the long arm hook".

The effects of clinical crown length on the sagittal movement of maxillary central incisor in clear aligner treatment: a finite element exploration.

Background: The mechanism of force application in clear aligner treatment involves wrapping the clinical crowns, suggesting that the size of the clinical crowns may impact tooth movement. The present finite element study aimed to explore the impact of clinical crown length on the sagittal movement of maxillary central incisor in clear aligner treatment.

Methods: The standard maxillary dentition model was developed using computer tomography scanning.

Lhx6 deficiency causes human embryonic palatal mesenchymal cell mitophagy dysfunction in cleft palate.

Background: Overconsumption of retinoic acid (RA) or its analogues/derivatives has been linked to severe craniomaxillofacial malformations, such as cleft palate and midface hypoplasia. It has been noted that RA disturbed the proliferation and migration of embryonic palatal mesenchymal (EPM) cells in these malformations, yet the exact mechanisms underlying these disruptions remained unclear.

Methods: A model of retinoic acid (RA)-induced cleft palate in fetal mice was successfully established.