Introduction: To guide deep overbite treatment, the effectiveness of clear aligners and the influence of maxillofacial characteristics were assessed in levelling the curve of Spee (COS). Methods: Forty-two patients underwent phased treatment using clear aligners. Digital dental models were created before and after treatment following which predicted outcomes, and dental cast measurements were conducted in addition to the analysis of lateral cephalometric and panoramic radiographs. The anticipated COS correction was compared with the actual correction achieved. Using multiple linear regression, associations between levelling effectiveness and clinical indicators were evaluated to establish prediction equations. P = 0.05 indicated statistical significance. Results: The levelling effectiveness was 71.8 ± 19.0%. The regression model accounted for 88.5% of the variance in levelling effectiveness ( F -value = 167.209, adjusted R ² = 0.885, Akaike information criterion [AIC] [E]=-146.94). The levelling effectiveness was related to the vertical skeletal pattern, the angulation of the mandibular incisors to the mandibular plane, the axial inclination of the mandibular anterior teeth, and the pre-treatment COS depth. Levelling effectiveness and other maxillofacial variables were not significantly related. Conclusion: Clear aligners effectively level the COS. Patients with a larger Frankfort-mandibular plane angle, a pre-treatment COS depth, and an incisor-mandibular plane angle, more easily achieved COS levelling using clear aligners. Those with smaller mandibular incisor parallelism still achieved effective levelling.

Objectives. The objective of this study is to develop a load-bearing prevascularized construct by combining calcium phosphate cement (CPC) with cells within a three-dimensional (3D) hydrogel culture system, to accelerate the regeneration of alveolar bone defects. Methods. A 3D co-culture system was established by encapsulating human periodontal ligament stem cells (hPDLSCs) and human umbilical vein endothelial cells (hUVECs) within a gelatin methacryloyl (GelMA) hydrogel on 3D-printed porous CPC scaffolds. The mechanical properties, pore structure and angiogenic potency were determined in vitro. In vivo performance was evaluated using a nude rat subcutaneous implantation model and a rat alveolar bone defect model. Four groups were tested: (1) Blank group (surgery-only group); (2) CPC+GelMA group (non-prevascularized group)；(3) CPC+GelMA-cell group (prevascularized group)；(4) Natural Periodontiumgroup. Results. The novel construct had good mechanical properties and biocompatibility. The 3D co-culture in GelMA successfully induced microvascular formation in vitro. Subcutaneous implantation in nude rats showed that the CPC+GelMA-cell group exhibited markedly greater angiogenic capacity than the CPC+GelMA group after 6 weeks, with a neovascular density 1.93-fold higher than that of the non-prevascularized group. Among all groups, the CPC+GelMA-cell group exhibited the strongest capacity for repairing rat alveolar bone defects. Compared to CPC+GelMA group, CPC+GelMA-cell group significant enhanced bone regeneration in rats by 1.23-1.37 folds, and increased vascularization by 2.65 folds (p＜0.05). Conclusions: The novel three-dimensional prevascularized CPC construct combined appropriate mechanical properties with great efficacy for alveolar bone regeneration and vascularization in vivo in an animal model.