Objective : This study aimed to investigate the effect of cAMP-responsive-element-binding protein (CREB) overexpression on the differentiation of human stem cells from the apical papilla (hSCAPs), stimulated by transforming growth factor- beta (TGF-β1). Methods: Cells were isolated from human immature third molars via enzymatic digestion. Four experimental groups were set up: ①a control group, receiving normal mineralization inducer (α-MEM, 10% FBS, 10 mmol/L β-sodium glycerophosphate, 50 μg/mL vitamin C, 10 nmol/L dexamethasone); ② a TGF-β1 group, receiving normal mineralization inducer and 5 μg/mL TGF-β1; ③ a TGF-β1+LV-empty group, receiving normal mineralization inducer and the transfected empty virus vector with 5 μg/mL TGF-β1; and ④ a TGF-β1+ov-CREB group, receiving normal mineralization inducer and the transfected CREB-overexpressing viral vector, with 5 μg/mL TGF-β1. The transfected cells were cultured in odontogenic medium in the presence or absence of TGF-β1 for 2 weeks. Alizarin red staining was used to detect mineralized nodules, and the mRNA expression of the mineralization genes runt-related transcription factor 2 (RUNX2), dentin sialophosphoprotein (DSPP) and alkaline phosphatase (ALP) was measured by qPCR. Results : Compared with the control group (1.12 ± 0.11), TGF-β1 inhibited the deposition of calcium minerals (0.67 ± 0.12) (P < 0.05) via hSCAPs and inhibited the mRNA expression of RUNX2 (0.60 ± 0.03), DSPP (0.43 ± 0.12) and ALP (0.69 ± 0.05) (P < 0.05). In contrast, overexpression of CREB attenuated the effect of TGF-β1 on hSCAPs, resulting in the development of a high number of mineralized nodules (1.27 ± 0.10) (P < 0.01) and increased RNA levels of RUNX2 (1.33 ± 0.07), DSPP (1.32 ± 0.11) and ALP (1.26 ± 0.03) (P<0.05) compared with those in the TGF-β1 group. Conclusion Overexpressed CREB promotes odontogenic differentiation of hSCAPs by interfering with TGF-β1.

Objective : The present study observed the clinical effects on reattachment and pulpotomy of young crown-fractured and pulp-exposed permanent incisors. Methods : In a one-year retrospective clinical observation study, 30 traumatic intact segments of permanent incisors with crown fracture and pulpal exposure were treated using a pulpotomy and reattachment technique with an enamel-dentin luting agent and composite resin. Results : The number of subsequent visit teeth was 30, 29, 25 at 1, 3, 6 months follow-up respectively. The pulpotomy success rates were 100% at 1 month, 93.1% at 3 months, 93.1% at 6 months. The retention rates using the reattachment technique were 100% at 1 month, 100% at 3 months, 100% at 6 months. Conclusion Pulpotomy is the preferred method of preserving live pulp after pulpal exposure of young permanent incisors, and the clinical effect is prominent. The fragment reattachment technique is an effective middle- and short-term method for temporary restoration of young crown-fractured permanent incisors.