Reprogramming mitochondrial metabolism of macrophages by miRNA-released microporous coatings to prevent peri-implantitis.

Although various new biomaterials have enriched the methods for peri-implant inflammation treatment, their efficacy is still debated, and secondary operations on the implant area have also caused pain for patients. Recently, strategies that regulate macrophage polarization to prevent or even treat peri-implantitis have attracted increasing attention. Here, we prepared a laser-drilled and covered with metal organic framework-miR-27a agomir nanomembrane (L-MOF-agomir) implant, which could load and sustain the release of miR-27a agomir. In vitro, the L-MOF-agomir titanium plate promoted the repolarization of LPS-stimulated macrophages from M1 to M2, and the macrophage culture supernatant promoted BMSCs osteogenesis. In a ligation-induced rat peri-implantitis model, the L-MOF-agomir implants featured strong immunomodulatory activity of macrophage polarization and alleviated ligation-induced bone resorption. The mechanism of repolarization function may be that the L-MOF-agomir implants promote the macrophage mitochondrial function and metabolism reprogramming from glycolysis to oxidative phosphorylation. Our study demonstrates the feasibility of targeting cell metabolism to regulate macrophage immunity for peri-implantitis inhibition and provides a new perspective for the development of novel multifunctional implants.

Application of Immediate Implant Placement Techniques in Peri-implantitis Modeling.

OBJECTIVES: To explore the use of immediate implant placement technique in peri-implantitis modeling, shorten the modeling period, and obtain similar effects. MATERIALS AND METHODS: Eighty rats were divided into 4 groups: immediate placement (IP), delayed placement (DP), IP-ligation (IP-L) and DP-ligation (DP-L). In the DP and DP-L groups, implants were placed 4 weeks after tooth extraction. In the IP and IP-L groups, implants were placed immediately. Four weeks later, the implants were ligated to induce peri-implantitis in the DP-L and IP-L groups. RESULTS: Nine implants were lost (3 in the IP-L and 2 each in the IP, DP, and DP-L group). The bone level decreased after ligation, and the buccal and lingual bone levels were lower in IP-L versus DP-L. The implant pullout strength was decreased after ligation. Micro-CT showed bone parameters were decreased after ligation, and the percent bone volume was higher in IP versus DP. Histology showed that the percent of CD4 + cells and IL-17 + cells was increased after ligation and higher in IP-L versus DP-L. CONCLUSIONS: We successfully introduced immediate implant placement into the modeling of peri-implantitis and observed similar bone resorption and more soft tissue inflammation in a shorter time.

[Assessment of the reproducibility of occlusal morphology for digital full crown designed by mandibular trajectory data].

PURPOSE: To metrically assess the reproducibility of mandibular trajectory data and mean frame parameter in guiding the design of occlusal morphology of prosthesis. METHODS: Fifteen subjects with complete dentition were selected, including 6 females and 9 males, with an average age of 22-30 years old. The mandibular trajectory data and mean frame parameter were used to guide the design of occlusal morphology of the prosthesis in the CAD system, then the occlusal morphology was compared to the original natural teeth. The data were statistically analyzed by SPSS 25.0 software package. RESULTS: The general deviation of occlusal morphology between the prosthesis guided by mandibular trajectory data and mean frame parameter with the natural teeth was as follows: mean positive distance was (269.9±63.1) µm, (318.7±51.3) µm; mean negative distance was (-175.8±78.2) µm, (-253.7±65.6) µm; root mean square (RMS) was (267.1±84.9) µm and (304.1±82.2) µm. The vertical distance on mesial buccal cusp was (197.6±86.2) µm and (288.0±79.6) µm，distal buccal cusp was (176.3±85.3) µm and (297.7±63.2) µm, mesial lingual cusp was (171.6±62.4) µm and (246.4±62.8) µm, distal lingual cusp was (166.2±64.6) µm and (232.5±70.7) µm, central fossa was (104.9±42.2) µm and (219.1±69.1) µm. RMS, mean(-) and vertical differences of central fossa and distal buccal cusp were significantly different(P＜0.05). CONCLUSIONS: The occlusal morphology of the prosthesis designed under the guidance of mandibular trajectory data and mean frame parameter both have significant differences with natural occlusion, but the deviation guided by mandibular trajectory data is lower.

Analysis of Th-cell subsets in local and systemic environments from experimental periodontitis rats.

OBJECTIVES: The objective of this study was to explore the effect of periodontitis on Th-cell subsets in local and systemic environments. METHODS: A total of 32 male Sprague-Dawley rats were randomly divided into periodontitis and control groups. Silk ligatures were applied to the mandibular first (M1) molars in the periodontitis group. Inflammation and alveolar bone loss around the M1 molars were analyzed by histological staining and microcomputed tomography. The mRNA expression of interferon-γ (IFN-γ), interleukin 4 (IL-4), IL-17, and IL-10 in the gingiva was measured by qRT-PCR. The proportions of Th1, Th2, Th17, and Treg cells in the submandibular lymph nodes, peripheral blood, and jaw bone marrow were tested using flow cytometry. RESULTS: More inflammatory cells and alveolar bone resorption were found in the periodontitis group, with upregulated mRNA expression of IFN-γ, IL-17, and IL-10. The proportion of Th1 and Th17 cells was significantly elevated in submandibular lymph nodes, and the proportion of Th1, Th2, and Th17 cells was significantly elevated in peripheral blood, while the proportion of Th1, Th17, and Treg cells was significantly elevated in jaw bone marrow in the periodontitis group. CONCLUSION: This study suggests that periodontitis affects the differentiation of Th-cell subsets in both local and systemic environments, resulting in an increased proportion of proinflammatory cells.

MicroRNA sequence and function analysis in peri-implantitis and periodontitis: An animal study.

OBJECTIVE: To compare miRNA expression levels and predict relevant target genes and signaling pathways in peri-implantitis and periodontitis. BACKGROUND: There are many differences between periodontitis and peri-implantitis. An understanding of the similarities and differences in the transcriptional patterns of these diseases, as well as the molecular mechanisms, is beneficial for the development of management strategies. MATERIALS AND METHODS: Rat models of periodontitis (PD, n = 6) and peri-implantitis (PI, n = 5) were established by ligation. Implantation without ligation (PIC, n = 5) and normal rats (PDC, n = 6) were used as controls. Micro-CT was used to confirm the successful establishment of the model. Gingiva was harvested for miRNA transcriptome sequencing, and the results were confirmed by qRT-PCR. miRNA target genes were predicted with miRTarBase. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed. RESULTS: Sixty-nine miRNAs were differentially expressed in PI vs. PD, 105 were differentially expressed in PI vs. PIC, and 70 were differentially expressed in PD vs. PDC (log2 FC ≥1 and padj <0.05). The upregulated genes in all three comparisons were mostly involved in the biological process response to stimulus, whereas most of the downregulated genes were involved in nervous system development (p < .01). The upregulated genes in PI vs. PD and PI vs. PIC were involved in Toll-like receptor signaling and RIG-I-like signaling. The upregulated genes in PI vs. PD were involved in T- and B-cell receptor signaling, apoptosis, and osteoclast differentiation. Focal adhesion was downregulated in all three comparisons, and adherens junction was downregulated in PI vs. PD and PD vs. PDC (p < .1). CONCLUSION: This study showed differences in the miRNA expression profiles between peri-implantitis and periodontitis and annotated the possible target genes and molecular mechanisms; this study could lay a foundation for the development of management strategies.