Peptide KN-17-Loaded Supramolecular Hydrogel Induces the Regeneration of the Pulp-Dentin Complex.

Regenerating the pulp-dentin complex remains a decisive factor during apexification for immature permanent teeth. Peptide KN-17, which was modified based on the structure of cecropin B, could effectively interfere with bacterial growth and induce the migration of human bone marrow stromal cells (hBMSCs). This study aimed to investigate the effect of KN-17 on the tissue regeneration. To our surprise, KN-17 can significantly stimulate angiogenesis in vitro and in vivo, which may provide a guarantee for apical closure. Herein, a novel peptide/KN-17 coassembled hydrogel is developed via a heating-cooling process. Npx-FFEY/KN-17 supramolecular hydrogel can induce vessel development, stimulate odontogenic differentiation of human dental pulp stem cells (hDPSCs), and exert an antibacterial effect on Enterococcus faecalis (E. faecalis). Furthermore, coronal pulp excised rat molars are supplied with KN-17 or KN-17-loaded hydrogel and transplanted subcutaneously in BALB/c-nu mice. After 4 weeks, the hydrogel Npx-FFEY/KN-17 stimulates the formation of multiple odontoblast-like cells and dentin-like structures. Our findings demonstrate that the KN-17-loaded hydrogel can promote the regeneration of the pulp-dentin complex for continued root development.

Antibacterial and Anti-Inflammatory Properties of Peptide KN-17.

Peri-implantitis, an infectious disease originating from dental biofilm that forms around dental implants, which causes the loss of both osseointegration and bone tissue. KN-17, a truncated cecropin B peptide, demonstrated efficacy against certain bacterial strains associated with peri-implantitis. This study aimed to assess the antibacterial and anti-inflammatory properties and mechanisms of KN-17. The effects of KN-17 on oral pathogenic bacteria were assessed by measuring its minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). Moreover, the cytotoxicity and anti-inflammatory effects of KN-17 were evaluated. KN-17 inhibited the growth of Streptococcus gordonii and Fusobacterium nucleatum during in vitro biofilm formation and possessed low toxicity to hBMSCs cells. KN-17 also caused RAW264.7 macrophages to transform from M1 to M2 by downregulating pro-inflammatory and upregulating anti-inflammatory factors. It inhibited the NF-κB signaling pathway by reducing IκBα and P65 protein phosphorylation while promoting IκBα degradation and nuclear P65 translocation. KN-17 might be an efficacious prophylaxis against peri-implant inflammation.

Study on Optimizing Novel Antimicrobial Peptides with Bifunctional Activity to Prevent and Treat Peri-Implant Disease.

The bacterial invasions and inflammatory responses after implant placement often affect osseointegration; the increased secretion of pro-inflammatory cytokines can lead to poor formation of bone and bone absorption. Previous research has shown that the antimicrobial peptide 6K-F17 has antibacterial and immunomodulatory properties. The objective of this study was to optimize KR-1 and KR-2, based on 6K-F17, to apply to the tissue around the oral implant. Our first objective is to study its antibacterial properties, and then we intend to further study its osteogenic ability to osteoblasts by modulating the immune response of macrophages. In this research, KR-1 and KR-2 can inhibit the formation of bacterial biofilm, and further kill bacteria S. gordonii and F. nucleatum by destroying the cell wall and cell membrane of bacteria. The novel peptides restrained the activation of the NF-κB signaling pathway by reducing the phosphorylation levels of IκBα and p65, inhibiting the degradation of IκBα and the nuclear translocation of p65, and increasing the percentage of M2 phenotype in macrophages. This suppressed the inflammatory response induced by lipopolysaccharides and enhanced the osteogenic activity of osteoblasts; this, in turn, promoted osteogenesis. The antimicrobial peptide KR-1 showed better performance. Our results demonstrate that KR-1 and KR-2 have antibacterial and bone immunomodulatory effects, and further promote osteogenesis by modulating the immune microenvironment, which provides the possibility for the adjuvant treatment of peri-implant diseases.

Effectiveness of cognitive behavioral therapy on kinesiophobia and oral health-related quality of life in patients with temporomandibular disorders, study protocol for a randomized controlled trial.

BACKGROUND: Temporomandibular disorders (TMD) is a common physical and psychological disease in dental department. Pain and mandibular limitation are the main reasons for patients to seek oral treatment. However, the presence of kinesiophobia, patients often catastrophize pain, so as to avoid mandibular movement, which seriously affects their quality of life. Cognitive behavioral therapy (CBT) has significant improvements in reducing kinesiophobia and quality of life in musculoskeletal disease, but has not been proved in TMD patients. The study aims to apply CBT on kinesiophobia and oral health related quality of life (OHRQOL) in TMD patients. METHODS: A total of 108 individuals between 18 and 65 years of age, who will be referred to the temporomandibular joint clinic of Stomatology Hospital of Tianjin Medical University in china will be randomized into 2 treatment arms. The control group will receive a conventional treatment, whereas the experiment group will receive CBT on the basis of the control group. The primary outcomes will be the kinesiophobia and OHRQOL, and will be measured by the Tampa scale for kinesiophobia for patients with Temporomandibular Disorders (TSK-TMD) and the Oral Health Impact Scale for patients with temporomandibular disorders (OHIP-TMDs), the secondary outcomes will be pain intensity measured by Numerical Rating Scale (NRS), pain catastrophizing measured by Pain Catastrophizing Scale (PCS), anxiety and depression measured by Hospital Anxiety and Depression Scale (HADS), and self-efficacy measured by General Self-Efficacy Scale (GSES). DISCUSSION: This study protocol reported a randomized controlled trial which aimed at assessing the effectiveness of the CBT versus conventional treatment with TMD. TRIAL REGISTRATION: Registered in the Chinese Clinical Trial Registration Center with the number ChiCTR2000038573. Registered 24 September 2020.