This review provides a comprehensive analysis of bacterial biomineralization, with an emphasis on the role of mi­croorganisms in mineralization processes. The historical context and evolution of research on bacterial mineralization are explored, with particular focus on the challenges and advancements in identifying bacterial biominerals through X-ray diffraction (XRD) methods. The authors present an XRD Determination Table for bacterial biominerals to facilitate the rapid identification of minerals produced by bacteria. The review also discusses the complexities of bacterial-induced mineraliza­tion, particularly in differentiating between biologically controlled and induced processes. Additionally, experimental stud­ies using free electron lasers to investigate the calcification potential of bacteria are described, revealing the formation of previously unreported mineral species. The findings highlight the diverse environmental conditions under which bacterial biomineralization occurs and suggest potential for discovering new biominerals through innovative experimental approaches. This work serves as a valuable resource for researchers in geomicrobiology and related fields, providing essential data and insights for future studies on microbial interactions with minerals.

We aimed to explore the roles of thin gingival phenotype and insufficient keratinized mucosal width (KMW) as risk indicators in peri-implantitis and peri-implant mucositis. Patients (100 in total) planted with bone level implants and soft tissue level implants during January 2021 and October 2024 were retrospectively selected. They were allocated to a KMW ≥2 mm group (n=48) and a KMW <2 mm group (n=52) on the basis of KMW. The mSBI of the thick gingival phenotype was significantly decreased at 6 months and 3-4 years compared with that of the thin gingival phenotype in both groups, while significant increases in the mSBI at 6 months and 3-4 years were observed from the bone level implants in comparison to those from the soft tissue level implants (P<0.05). In the two groups, the mPLI of the thick gingival phenotype declined significantly at 6 months, 1 year, and 3-4 years in comparison to that of the thin gingival phenotype, whereas the bone-level implants presented significantly higher mPLI than the soft tissue level implants at 6 months and 1 year (P<0.05). The KMW ≥2 mm group had significantly smaller proportions of patients with peri-implant mucositis and peri-implantitis in the bone level implants and soft tissue level implants than the KMW <2 mm group (P<0.05). Thin gingival phenotype and insufficient KMW can be used as risk indicators for assessing the occurrence of peri-implantitis and peri-implant mucositis, for which targeted preventive and therapeutic measures can be taken.

This study aimed to compare marginal bone level changes around implants placed using two forms of porcine-derived xenografts—particulate and collagen-containing block—and to assess their clinical performance relative to native bone healing. This retrospective study included 267 patients (444 implants) who underwent ridge augmentation or sinus floor elevation using either particulate or collagenous block-type porcine bone grafts. Patients were classified into three groups: collagenous block-type graft for ridge augmentation, powder-type graft for ridge augmentation, and sinus graft without marginal ridge augmentation as the control group. The third group served as a control to assess natural bone healing. Marginal bone loss was measured using standardized periapical radiographs, and implant stability was assessed using ISQ values. Both graft groups demonstrated comparable early and late marginal bone loss without any complications. The collagenous block-type showed lower secondary ISQ values (79.4 ± 8.8 and 82.2 ± 4.9, p=0.006). The control group exhibited the least initial marginal bone loss, despite the absence of marginal grafting, highlighting the natural healing potential of native bone. Porcine-derived grafts, whether in collagenous block or powder form, showed stable peri-implant bone outcomes comparable to sites with no marginal grafting. These findings support their clinical reliability in implant therapy.

This study evaluated the effects of blue light-emitting diode (LED)-induced photobiomodulation (PBM) on growth and chondrocyte differentiation in organ-cultured rat mandibular condyles under conditions free from systemic influences. Mandibular condyles were harvested from embryonic day 21 Sprague-Dawley rat fetuses and cultured for 8 days. Samples were assigned to four groups: baseline (day 0), control (no irradiation), 100 mW LED, and 1,000 mW LED. Blue LED light (455 nm) was applied for 30 seconds daily for five consecutive days. Histological and morphometric analyses were performed to assess changes in tissue architecture and condylar dimensions. The 1,000 mW group showed significant increases in the thickness of the mature chondrocyte layer and vertical condylar length compared to the control and baseline groups (p < 0.05). Both LED-irradiated groups demonstrated enhanced chondrocyte differentiation, with the 1,000 mW group showing the most pronounced effects. The superficial and proliferative layers were thinner in the 1,000 mW group, suggesting accelerated cellular progression toward maturity. Blue LED-induced PBM promoted growth and chondrocyte differentiation in the mandibular condyle under organ culture conditions. These findings suggest that PBM may serve as a promising, non-invasive modality to support cartilage development and regeneration, particularly in the context of temporomandibular joint disorders.

Chronic periodontitis, a common inflammatory disease, is exacerbated by lipopolysaccharide (LPS), a major gram-negative bacterial component that activates the immune system, triggers proinflammatory responses, and disrupts periodontal ligament stem cell (PLSC) function. The effects of LPS on the osteogenic differentiation of and proinflammatory cytokine secretion by PLSCs were investigated using a cytokine array, RT‒PCR, flow cytometry, and Alkaline phosphatase (ALP) staining. This study focused on analyzing the mechanism by which PLSCs exacerbate chronic periodontitis through the regulation of M1 macrophage polarization. LPS treatment significantly promoted the secretion of proinflammatory cytokines by PLSCs, which not only increased macrophage recruitment but also induced M1 polarization. Further analysis revealed that LPS-induced proinflammatory cytokine secretion by PLSCs inhibits the osteogenic potential of PLSCs through the regulation of M1 macrophage polarization and increases TNF-α expression. LPS, by affecting the paracrine characteristics of PLSCs and immune cell polarization, may be a key factor underlying the persistent inflammation and impaired periodontal tissue repair in chronic periodontitis. Targeting the mechanisms of LPS action, particularly by inhibiting TNF-α and its receptors, may provide new intervention strategies for the treatment of chronic periodontitis. This study offers valuable insights into the pathogenesis of chronic periodontitis and potential therapeutic approaches.

This study investigated the effects of repeated helium-neon (He-Ne) laser-based photobiomodulation therapy (PBMT) on bone healing in a rat femoral defect model. Bilateral 0.8-mm monocortical bone defects were created in the distal femurs of Sprague-Dawley rats, with one side receiving repeated He-Ne laser irradiation (632.8 nm, 25 mW, 7.5 J) and the other serving as a control. Histological and image-based bone density analyses were performed on postoperative days 7 and 14. The irradiated group exhibited enhanced trabecular bone formation and significantly higher bone density on day 7, particularly in the marrow region. However, bone density decreased in this group by day 14, suggesting progression to bone remodeling. These findings indicate that PBMT using He-Ne laser promotes early-stage bone formation and may accelerate the bone healing process, thus supporting the therapeutic potential of PBMT for bone regeneration.

Osteoarthritis (OA) is a progressive joint disorder characterized by cartilage degradation, inflammation, and chondrocyte dysfunction, with mitochondrial dysfunction and oxidative stress being central to its pathogenesis. The Nrf2 pathway is vital for maintaining redox homeostasis and mitochondrial integrity. This study investigated the protective effects of Ophiopogonin D (OP-D), a natural saponin compound, on IL-1β-induced chondrocyte injury in vitro. Using C28/I2 cells, we demonstrated that OP-D restored cell viability and reduced the secretion of proinflammatory cytokines following IL-1β exposure. OP-D also alleviated mitochondrial dysfunction by decreasing mitochondrial ROS production and preserving mitochondrial membrane potential. Furthermore, OP-D mitigated extracellular matrix degradation. Mechanistically, OP-D activated the Keap1/Nrf2 pathway. These findings suggest that OP-D exerts chondroprotective effects by improving mitochondrial function and maintaining ECM integrity via Nrf2 pathway activation, highlighting its therapeutic potential for the treatment of osteoarthritis.