To analyze the different fabrication methods and surface structure of treated dentin matrix (TDM) and demineralized dentin matrix (DDM) and their diverse function on promoting the proliferation and osteogenic differential capability of human periodontal ligament cells (hPDLCs). This study provides a preliminary basis for the treatment of periodontal bone defects with bone substitutes from teeth.

TDM was made from human dentin matrices and demineralized incompletely by soaking in different concentrations of ethylene diamine tetra-acetic while DDM was made of human dentin matrices and demineralized completely by soaking in a hydrochloric acid solution followed by observation via SEM. The liquid extracts of TDM and DDM were collected according to the protocol of the International Standardization Organization (ISO 10993). Then, hPDLCs were divided into the following three groups: the TDM group (liquid extracts of TDM), the DDM group (liquid extracts of DDM), the control group (a-modified eagle medium with 10% fetal bovine serum), hPDLCs were cultured with liquid extracts of TDM or DDM, or a-modified eagle medium with 10% FBS). hPDLC proliferation was detected by a Cell Counting Kit-8 (CCK-8). The alkaline phosphatase (ALP) expression and calcified nodules of hPDLCs were tested.

TDM obtained a preferable surface structure compared to DDM due to more sufficiently exposed dentinal tubules and looser fiber bundles of the intertubular and peritubular dentin. Both TDM and DDM promoted the proliferation of hPDLCs compared with the control group, and the proliferation of hPDLCs was significantly greater in the TDM group compared to the DDM group (F = 36.480, P < 0.05). The ALP activity of hPDLCs in the TDM group was higher than the DDM group. After a 14-day osteogenic induction, Alizarin red staining mineral nodes were observed in both groups; however, the TDM group displayed more calcified nodules than the DDM group.

The advantages of TDM including the surface structure, proliferation and osteogenic differentiation of hPDLCs, are more prominent than those of DDM, suggesting that TDM is a potential promising bone graft substitute in periodontal regeneration.

Exploring the effects of susceptibility genes on aggressive periodontitis during its occurrence and development lays a foundation for further research on its genetic pathogenesis.

Medical history and clinical indicators were collected from monozygotic twins with generalized aggressive periodontitis. Susceptibility genes were detected by polymerase chain reaction-restriction fragment length polymorphisms, and the exon gene components were analyzed by whole-exome sequencing.

The severity of generalized aggressive periodontitis in the twins was different (P < 0.05). Florida diagnosis results showed that the younger sister’s explored clinical depth (probing depth, PD) and clinical attachment loss (CAL) were higher than those for the elder sister, but her clinical bleeding index (bleeding on probing, BOP) was lower than that of the elder sister. In addition, their responses to periodontal basic treatment were different (P < 0.05). After treatment, the improvement of CAL and decline in BOP were more obvious in the elder sister, and the proportion of different periodontal pocket depths in the elder sister decreased after treatment, while the decrease was slighter in the younger sister. Genetic tests revealed that the twins had the same genotypes at target susceptibility genes (IL-1β-511, IL-1β+3953, TNF-α-308, FcγR-IIIb, VDR, and ER) and differential exon gene components, and that the suspected differential genes, e.g. ZFPM1, PTH2, ZFYVE16, and LY6G6C, might be related to their phenotypic differences.

These monozygotic twins had different phenotypes of generalized aggressive periodontitis. Their shared susceptibility genes increased the risk of disease, and their different genetic mutations affected the phenotype of the disease.

The purpose of this study was to investigate the effect of different concentrations of exosomes (Exos) secreted from dental folic cells (DFCs) preconditioned with lipopolysaccharide (LPS) on the osteogenic differentiation ability of periodontal cells in periodontitis (p-PDLCs) in patients to provide a basis for the prevention and treatment of periodontal disease.

Tissue block and enzyme digestion methods were used to culture DFCs and p-PDLCs. Exosomes were isolated from 250 ng/mL LPS-preconditioned DFCs 24 h later. The characteristics of exosomes were detected by transmission electron microscopy, particle size analysis and Western blotting. The effects of 10 μg/mL and 100 μg/mL exosomes on the osteogenic differentiation of p-PDLCs were detected by RT-PCR and Alizarin red staining.

LPS-pretreated DFC-derived exosomes (L-Exos) are vesicle-like structures with a size between 30-100 nm that positively express CD63 and Alix. Compared with the control group, exosomes significantly upregulated Periostin, Col Ⅰ, and Col Ⅲ expression at 100 μg/mL (P < 0.05), while TGF- β1 was significantly upregulated at 10 μg/mL (P < 0.01). At 7 days after osteogenic induction, mineralized nodules were significantly more abundant in the exosome group than in the control group (P < 0.01), and the results were better at a concentration of 100 μg/mL (P < 0.01).

100 μg/mL L-Exos are better than 10 μg/mL L-Exos in enhancing the osteogenic differentiation ability of p-PDLCs.