Periodontitis is a significant independent risk factor for atherosclerosis. Yet, the exact mechanism of action is still not fully understood. In this study, we investigated the effect of exosomes‐miR‐155‐5p derived from periodontal endothelial cells on atherosclerosis in vitro and in vivo. Higher expression of miR‐155‐5p was detected in the plasma exosomes of patients with chronic periodontitis (CP) and carotid atherosclerosis (CAS) compared to patients with CP. Also, the expression level of miR‐155‐5p was associated with the severity of CP. miR‐155‐5p‐enriched exosomes from HUVECs increased the angiogenesis and permeability of HAECs and promoted the expression of angiogenesis, permeability, and inflammation genes. Along with the overexpression or inhibition of miR‐155‐5p, the biological effect of HUVECs‐derived exosomes on HAECs changed correspondingly. In ApoE−/− mouse models, miR‐155‐5p‐enriched exosomes promoted the occurrence of carotid atherosclerosis by increasing permeable and angiogenic activity. Collectively, these findings highlight a molecular mechanism of periodontitis in CAS, uncovering exosomal miR‐155‐5p derived periodontitis affecting carotid endothelial cells in an ‘exosomecrine’ manner. Exosomal miR‐155‐5p may be used as a biomarker and target for clinical intervention to control this intractable disease in future, and the graphic abstract was shown in Figure .

Purpose: Root-canal anatomy can limit irrigant access. Bubble dynamics in distilled water were examined for plasma-mediated 1064-nm Nd: YAG laser-induced optical breakdown (LIOB) and thermally driven 2940-nm Er: YAG laser-activated irrigation (LAI) to guide confined-model testing. Methods: LIOB was tested at 100, 200 and 300 mJ/pulse and LAI at 10, 15 and 20 mJ/pulse. Ten independent bubble events per setting were imaged at 50,000 frames/s. Projected size, lifetime, frame-averaged apparent expansion rates, aspect ratio and first rebound were compared using Kruskal–Wallis and Holm-adjusted Mann–Whitney U tests. Results: Chain-like plasma luminescence preceded LIOB bubble formation. Median primary equivalent diameters were 3.21, 4.39 and 4.72 mm in LIOB and 2.24, 2.60 and 2.89 mm in LAI. The LIOB increment was smaller at 200–300 mJ than at 100–200 mJ. Axial apparent expansion was lower and transverse expansion generally higher with LIOB. Rebound-to-primary ratios were 0.65–0.74 for LAI and 0.57–0.61 for LIOB, while absolute rebounds were larger with 200/300-mJ LIOB. Conclusion: Under the tested, non-energy-matched configurations, LIOB and LAI produced different bubble sequences and growth patterns. The results provide a free-water benchmark for confined-model experiments, but do not establish pressure safety, cleaning efficacy or superiority.