[Clinical effect of MB-PDT assisted initial therapy on alveolar angle absorption of lower anterior teeth].

PURPOSE: To evaluate the effect of MB-PDT assisted essential therapy on angle resorption of lower anterior alveolar bone in patients with periodontitis. METHODS: Forty patients who were diagnosed with periodontitis stage III-IV or C, lower anterior teeth alveolar bone angle resorption, and periodontal pocket depth greater than 4 mm were selected from April 2018 to October 2020 in the Department of Periodontology and Oral Mucosal Diseases, Changsha Stomatological Hospital. The patients were randomly divided into control group and experimental group with 20 cases in each group. Compared with the control group which was only managed with essential treatment, the experimental group was treated with MB-PDT on the basis of the control group. The plaque index (PLI) and gingival bleeding index (GBI) scores of the two groups were recorded before surgery and 1 and 2 weeks after surgery. Probing depth (PD) and clinical attachment level (CAL) were detected before and 6 months after surgery. Statistical analysis of the data was performed using Graphpad Prism 5 software package. RESULTS: The PLI and GBI of the experimental group were significantly lower than those of the control group at 1 and 2 weeks after operation(P＜0.05). Six months after surgery, PD and CAL levels in the experimental group were significantly lower than those in the control group (P＜0.05). CONCLUSIONS: MB-PDT adjuvant therapy has the advantages of simple operation, efficient sterilization, promotion of healing, and high safety performance. It may be a new non-surgical adjuvant treatment strategy for effective treatment of lower anterior alveolar angular resorption.

Dual-sensitive antibacterial peptide nanoparticles prevent dental caries.

Background: Dental caries is the most prevalent bacterial biofilm-induced disease. Current clinical prevention and treatment agents often suffer from adverse effects on oral microbiota diversity and normal tissues, predominately arising from the poor biofilm-targeting property of the agents. Methods: To address this concern, we herein report dual-sensitive antibacterial peptide nanoparticles pHly-1 NPs upon acid and lipid-binding for treatment of dental caries. Amino acid substitutions were performed to design the peptide pHly-1. The potential, morphology and secondary structure of pHly-1 were characterized to elucidate the mechanisms of its pH and lipid sensitivity. Bacterial membrane integrity assay and RNA-seq were applied to uncover the antimicrobial mechanism of peptides under acidic condition. The in vitro and ex vivo antibiofilm assays were used to determine the antibiofilm performance of pHly-1 NPs. We also carried out the in vivo anti-caries treatment by pHly-1 NPs on dental caries animal model. Oral microbiome and histopathological analyses were performed to assess the in vivo safety of pHly-1 NPs. Results: The pHly-1 peptide underwent the coil-helix conformational transition upon binding to bacterial membranes in the acidic cariogenic biofilm microenvironment, thereby killing cariogenic bacteria. Under normal physiological conditions, pHly-1 adopted a ß-sheet conformation and formed nanofibers, resulting in negligible cytotoxicity towards oral microbes. However, in acidic solution, pHly-1 NPs displayed reliable antibacterial activity against Streptococcus mutans, including standard and clinically isolated strains, mainly via cell membrane disruption, and also suppressed in vitro and human-derived ex vivo biofilm development. Compared to the clinical agent chlorhexidine, in vivo topical treatment with pHly-1 NPs showed an advanced effect on inhibiting rat dental caries development without adverse effects on oral microbiota diversity and normal oral or gastric tissues. Conclusion: Our results demonstrated the high efficacy of dual-sensitive antimicrobial peptides for the selective damage of bacterial biofilms, providing an efficient strategy for preventing and treating dental caries.