To study the biomechanical changes induced by differences in perioral force in patients with missing anterior maxillary teeth at rest via finite element analysis (FEA). Using conical beam CT (CBCT) images of a healthy person, models of the complete maxillary anterior dental region (Model A) and maxillary anterior dental region with a missing left maxillary central incisor (Model B) were constructed. The labial and palatine alveolar bone and tooth surface of the bilateral incisor and cusp regions were selected as the application sites, the resting perioral force was applied perpendicular to the tissue surface, and the changes in maxillary stress and displacement after the perioral force was simulated were analyzed. Compared with Model A, the labial alveolar bone in the missing tooth area of Model B shows significant stress concentration under the action of perioral force. This adverse stress is distributed in an inverted V-shape, concentrated at the top of the labial alveolar ridge and gradually decreases toward the root. In the resting state, labial soft tissue exerts adverse stress on the alveolar ridge in areas missing maxillary anterior teeth. This stress may affect alveolar bone healing, causing a reduction in alveolar bone width.

Background: The present study aimed to investigate the expression of stromal cell‐derived factor‐1 (SDF‐1) after tooth extraction in rats and its regulatory effect on the expression of osteopontin (OPN) and vascular endothelial growth factor (VEGF). Methods: The first mandibular molar of the rats on the left was extracted, the histopathological changes of the extraction sockets were observed, and the SDF‐1 protein and mRNA expression were measured at 0, 1, 4, 7, 10, and 14 days. Furthermore, we used AMD3100 to block SDF‐1/CXC chemokine receptor 4 (CXCR4) signaling, and the expression changes of SDF‐1, OPN, and VEGF were observed. Results: At 1 day, the socket was filled with a blood clot. At 4 days, the granulation tissues were formed at the socket. At 7 days, the extraction socket was filled with mature fibrous connective tissue. At 10 days, a large amount of new trabecular bone was regenerated. At 14 days, the newly formed socket bone underwent remodeling. The expression level of SDF‐1 began to increase on the first day after tooth extraction and then peaked at 4 days. Then, SDF‐1 expression gradually declined and finally returned to the baseline level at 14 days. Moreover, the application of AMD3100 decreased the secretion of OPN and VEGF, both at protein and mRNA levels. Conclusions: The expression of SDF‐1 increased first and then decreased after tooth extraction. SDF‐1 may play a regulatory role in the expression of OPN and VEGF. Plain language summary: Tooth extraction is one of the most common operations that cause oral tissue defects and tooth loss. The healing of the tooth extraction wound affects the results of the later denture restoration and implant surgery. In this study, the expression of stromal cell‐derived factor‐1 (SDF‐1) increased first and then decreased after tooth extraction. It was found that after blocking the SDF‐1 signaling pathway, the expression levels of osteopontin (OPN) and vascular endothelial growth factor (VEGF) decreased correspondingly. While OPN was a marker of bone maturation, VEGF could promote angiogenesis and thus tissue repair. In conclusion, SDF‐1 may be involved in the process of tissue damage repair by regulating the expression of OPN and VEGF.

Immediately placed implants with immediate provisionalization have become attractive options for patients and clinicians. However, there is no agreement on the esthetic advantages of immediately placed implants with immediate provisionalization. The aim of this systematic review and meta-analysis will be to assess the effect of immediate provisionalization on the clinical esthetic outcomes of immediately placed implants in a single-tooth implant of the esthetic area. An electronic search of MEDLINE/PubMed, EMBASE, Web of Science, Clinicaltrials.org., Cochrane Library, China Biology Medicine (CBM), Wan Fang Database, China National Knowledge Infrastructure Database (CNKI), and VIP Science Technology Periodical Database will be performed. The search will be carried out in the databases for articles published until May 2021. Two researchers will independently perform the literature selection, data extraction and quality assessment. Only randomized controlled trials (RCTs) reporting on the impact of immediate provisionalization on the clinical esthetic outcomes of implants immediately placed in a single-tooth implant of the aesthetic area will be included. The primary outcome of this study will be the esthetic outcome assessed by the objective index and patient satisfaction. The survival rate of implants and restorations and the changes in mucosa and bone around implants will also be analyzed. The included studies will be analyzed by Review Manager 5.3, and a meta-analysis will be performed. The study will evaluate the clinical esthetic outcomes of immediately placed implants with and without immediate provisionalization in single-tooth implants of the esthetic area. The results will provide clinicians with a better treatment approach in their application. This systematic review and meta-analysis will provide more reliable, evidence-based data for the impact of immediate provisionalization on the clinical esthetic outcomes of immediately placed implants, which may or may not be beneficial. PROSPERO registration number: CRD42021221669.

To investigate the effects of Bletilla striata polysaccharides (BSPs) on the proliferation and migration of human gingival fibroblasts (HGFs) on titanium surfaces and clarify the regulatory role of the PI3K/AKT signaling pathway. Primary HGFs were isolated from healthy gingival tissues and subjected to hematoxylin‒eosin (HE) staining and immunofluorescence (purity ≥ 95%). HGFs were cocultured with titanium sheets and divided into control, BSP (800 µg/mL, optimal concentration), and BSP + wortmannin (WM, PI3K inhibitor) groups. Cell proliferation was evaluated by a CCK-8 assay, live/dead staining, and quantitative real-time PCR (qRT‒PCR) for Ki67 and PCNA mRNA expression. Cell migration was detected by scratch wound healing and Transwell assays. ELISA was used to measure the secretion of fibronectin (FN) and type I collagen (COLI) in the culture medium. Scanning electron microscopy (SEM) was used to observe the cell morphology on the titanium surfaces. HE staining and immunofluorescence confirmed the successful isolation and identification of HGFs. BSPs significantly promoted HGF proliferation, as evidenced by increased CCK-8 absorbance, a higher live cell ratio, an increased proportion of Ki67/PCNA double-positive cells, and increased mRNA and protein expression levels of Ki67 and PCNA (P < 0.01). Scratch and Transwell assays revealed that BSPs enhanced HGF migratory capacity, accompanied by increased secretion of FN and COLI (P < 0.01). SEM revealed that BSPs improved cell spreading and surface coverage on titanium. Mechanistically, BSPs activated the PI3K/AKT pathway, and WM cotreatment abolished both the pathway activation and the proproliferative and promigratory effects of BSPs. BSPs promote the proliferation and migration of HGFs on titanium surfaces by activating the PI3K/AKT signaling pathway, which is associated with the upregulation of Ki67 and PCNA expression and increased FN and COLI secretion. This study provides experimental evidence for the potential application of BSPs as bioactive agents in peri-implant soft tissue regeneration, but these findings require further in vivo validation.