The expression of signal regulatory protein alpha (SIRPα) in periodontal cells and tissue.

Signal regulatory protein alpha (SIRPα) is mainly expressed by cells of myeloid origin. This membrane glycoprotein is shown to be involved in regulation of different inflammatory conditions, such as colitis and arthritis. However, SIRPα has not been investigated in relationship to periodontitis, an inflammatory condition affecting the tooth supporting tissues. We aim to investigate if resident cells in the periodontium express SIRPα and whether a possible expression is affected by inflammatory conditions. Primary human keratinocytes, fibroblasts, periodontal ligament cells, and osteoblasts were cultured with or without the pro-inflammatory cytokines tumor necrosis factor alpha (TNF-α) or interleukin-1-beta (IL-1ß). All different periodontal cell types showed a basal mRNA expression of SIRPα. Pro-inflammatory cytokines induced a 2-3-fold significant increase in SIRPα expression in both cultured human gingival fibroblasts and osteoblasts but neither in keratinocytes nor in periodontal ligament cells. Tissue sections from human gingival tissue biopsies were histochemically stained for SIRPα. Epithelial keratinocytes and gingival fibroblasts stained positive in sections from periodontally healthy as well as in sections from periodontitis. In periodontitis sections, infiltrating leukocytes stained positive for SIRPα. We highlight our finding that oral keratinocytes, gingival fibroblasts, and periodontal ligament cells do express SIRPα, as this has not been presented before. The fact that inflammatory stimulation of gingival fibroblasts increased the expression of SIRPα, while an increased expression by gingival fibroblasts in periodontitis tissue in situ could not be detected, is indeed contradictory.

Mechanisms of mechanical force in periodontal homeostasis: a review.

Mechanical forces affect periodontal health through multiple mechanisms. Normally, mechanical forces can boost soft and hard tissue metabolism. However, excessive forces may damage the periodontium or result in irreversible inflammation, whereas absence of occlusion forces also leads to tissue atrophy and bone resorption. We systemically searched the PubMed and Web of Science databases and found certain mechanisms of mechanical forces on immune defence, extracellular matrix (ECM) metabolism, specific proteins, bone metabolism, characteristic periodontal ligament stem cells (PDLSCs) and non-coding RNAs (ncRNAs) as these factors contribute to periodontal homeostasis. The immune defence functions change under forces; genes, signalling pathways and proteinases are altered under forces to regulate ECM metabolism; several specific proteins are separately discussed due to their important functions in mechanotransduction and tissue metabolism. Functions of osteocytes, osteoblasts, and osteoclasts are activated to maintain bone homeostasis. Additionally, ncRNAs have the potential to influence gene expression and thereby, modify tissue metabolism. This review summarizes all these mechanisms of mechanical forces on periodontal homeostasis. Identifying the underlying causes, this review provides a new perspective of the mechanisms of force on periodontal health and guides for some new research directions of periodontal homeostasis.

Intraoral Ultrasound Imaging Using a Rotational Transducer with Periodontal Feature Identification by Machine Learning.

Innovative intraoral ultrasound devices with smart artificial intelligence-based identification for dento-anatomy could provide crucial information for oral health diagnosis and treatment and shed light on real-time detection of developmental dentistry. However, the grand challenge is that the current ultrasound technologies are meant for external use due to their bulkiness and low frequency. We report a compact versatile ultrasound intraoral device that consists of a rotational probe head robustly pivoted around a hand-held and portable handle for real-time imaging of intraoral anatomy using high-frequency ultrasonography (up to 25 MHz). The intraoral ultrasound device that could be adjusted for various orientations of the imaging planes by rotating the head provides real-time, high-resolution ultrasonograms of intraoral structures, including dento-periodontium of most tooth types and maxillary palate. Machine learning-based algorithms are integrated to automate the identification of important structures, including alveolar bone and cementum-enamel junction. The intraoral ultrasound device smartened with artificial intelligence could innovate oral health diagnosis and treatment plans toward precision health and patient care.

[The effectiveness of photodynamic effects on the clinical and functional state of periodontal tissues in periodontitis]. / Effektivnost' fotodinamicheskogo vozdeistviya na kliniko-funktsional'noe sostoyanie tkanei parodonta pri parodontite.

The aim the study. Increasing the effectiveness of treatment of chronic generalized periodontitis of moderate severity according to microhemodynamics and oxygenation in periodontal tissues. MATERIALS AND METHODS: A clinical and functional study and treatment of chronic generalized periodontitis of moderate degree were conducted in 56 people (22 men and 34 women) aged 37 to 55 years. The patients were divided into 2 groups depending on the type of treatment: group 1 (main) - 28 people (11 men and 17 women, the average age of the group was 43.5±2.8 years, photodynamic therapy (PDT) with 1% dimegin gel using an AFS Spectrum LED emitter with a wavelength of 660 nm and an energy density of 95 J/cm2), in group 2 (control) - 28 people. (9 men and 19 women, the average age of the group was 45.0±3.1 years) standard treatment was performed without PDT. The level of tissue blood flow, its activity and vasomotor activity of microvessels, as well as the blood flow bypass index were determined by laser Doppler flowmetry. The study of oxygenation was carried out by optical tissue oximetry with determination of the index of oxygenation, specific oxygen consumption and perfusion oxygen saturation. RESULTS: After PDT, the periodontal tissues showed an increase in blood flow by 65.5% after 3 months, the level of oxygen metabolism increased by 51%, which increased after 6 months. The use of PDT in the complex treatment of chronic generalized periodontitis of moderate severity has an activating effect on the microcirculation system and the level of oxygen metabolism in periodontal tissues both in the near and long-term follow-up periods. CONCLUSIONS: The use of PDT with 1% dimegin gel has an effective effect on the state of microhemodynamics and oxygenation in periodontal tissues.

Xenogenous implanted dental follicle stem cells promote periodontal regeneration through inducing the N2 phenotype of neutrophils.

BACKGROUND: Periodontal tissue loss is the main reason for tooth mobility and loss caused by periodontal disease. Dental follicle stem cells (DFSCs) have significant therapeutic potential in periodontal regeneration, which maybe mainly depends on their potent immunomodulatory capacity. Consequently, this study aims to elucidate the impact of implanted xenogenous DFSCs on innate immune responses during early and late stages in the periodontal defect repair period. METHODS: To trace and investigate the immunomodulation mechanisms of DFSCs in vivo, DFSCs were engineered (E-DFSCs) using lentiviral vectors expressing CD63-enhanced green fluorescent protein (CD63-EGFP) and ß-Actin-mCherry protein (ACTB-mCherry) to exhibit green and red fluorescence. The biological characteristics and functions of E-DFSCs were verified by proliferation, differentiation, and co-culture experiments in vitro. In vivo, the periodontal regeneration capacity of E-DFSCs was detected by implantation of murine periodontal defect model, and the response of innate immune cells was detected at the 1st, 3rd, and 5th days (early stage) and 4th week (late stage) after implantation. RESULTS: In vitro assessments showed that E-DFSCs retain similar properties to their non-engineered counterparts but exhibit enhanced macrophage immunomodulation capability. In mice models, four-week micro-CT and histological evaluations indicated that E-DFSCs have equivalent efficiency to DFSCs in periodontal defect regeneration. At the early stage of repair in mice periodontal defect, fluorescence tracking showed that implanted E-DFSCs might primarily activate endogenous cells through direct contact and indirect actions, and most of these cells are myeloperoxidase-positive neutrophils. Additionally, compared with the control group, the neutrophilic infiltration and conversion of N2-type were significantly increased in the E-DFSC group. At the late stage of defect regeneration, more M2-type macrophages, fewer TRAP + osteoclasts, and an upregulated OPG/RANKL ratio were detected in the E-DFSC group compared to the control group, which indicated that immune balance tilts towards healing and bone formation. CONCLUSION: The xenogenous implanted DFSCs can induce the N2 phenotype of neutrophils in the early stage, which can activate the innate immune mechanism of the host to promote periodontal tissue regeneration.

Hierarchical Biomaterial Scaffolds for Periodontal Tissue Engineering: Recent Progress and Current Challenges.

The periodontium is a complex hierarchical structure composed of alveolar bone, periodontal ligament, cementum, and gingiva. Periodontitis is an inflammatory disease that damages and destroys the periodontal tissues supporting the tooth. Periodontal therapies aim to regenerate the lost tissues, yet current treatments lack the integration of multiple structural/biochemical instructive cues to induce a coordinated regeneration, which leads to limited clinical outcomes. Hierarchical biomaterial scaffolds offer the opportunity to recreate the organization and architecture of the periodontium with distinct compartments, providing structural biomimicry that facilitates periodontal regeneration. Various scaffolds have been fabricated and tested preclinically, showing positive regenerative results. This review provides an overview of the recent research on hierarchical scaffolds for periodontal tissue engineering (TE). First, the hierarchical structure of the periodontium is described, covering the limitations of the current treatments used for periodontal regeneration and presenting alternative therapeutic strategies, including scaffolds and biochemical factors. Recent research regarding hierarchical scaffolds is highlighted and discussed, in particular, the scaffold composition, fabrication methods, and results from in vitro/in vivo studies are summarized. Finally, current challenges associated with the application of hierarchical scaffolds for periodontal TE are debated and future research directions are proposed.

Sex steroid hormones: an overlooked yet fundamental factor in oral homeostasis in humans.

Sex steroid hormones (SSH) are extremely versatile molecules with a myriad of physiological functions. Next to their well-known role in sexual development and reproduction, SSH play active roles in practically every tissue in the human body, including the oral cavity. It has long been demonstrated that periodontal tissues express SSH receptors and therefore are responsive to the presence of SSH. Interestingly, SSH not only interact with the periodontal tissues but also with other tissues in the oral cavity such as dental enamel, pulp, cementum, oral mucosa, and salivary glands. Questions concerning the possible physiological functions of these receptors and their role in maintenance of oral health, remain unanswered. The purpose of this scoping review was to gather and summarize all the available evidence on the role of SSH in physiological processes in the oral cavity in humans. Two comprehensive literature searches were performed. References were screened and selected based on title, abstract and full text according to our inclusion criteria. Both searches yielded 18,992 results of which 73 were included. Results were divided into four categories: (1) Periodontium; (2) Dental structure; (3) Mucosa; and (4) Salivary glands. The interaction of these tissues with progestagens, androgens and estrogens are summarized. Sex steroid hormones are an overlooked yet fundamental factor in oral homeostasis. They play important roles in the development and function of the periodontium, dental structure, mucosa and salivary glands. Dentists and healthcare providers should consider these hormonal factors when assessing and treating oral health conditions.

Nonionizing diagnostic imaging modalities for visualizing health and pathology of periodontal and peri-implant tissues.

Radiographic examination has been an essential part of the diagnostic workflow in periodontology and implant dentistry. However, radiographic examination unavoidably involves ionizing radiation and its associated risks. Clinicians and researchers have invested considerable efforts in assessing the feasibility and capability of utilizing nonionizing imaging modalities to replace traditional radiographic imaging. Two such modalities have been extensively evaluated in clinical settings, namely, ultrasonography (USG) and magnetic resonance imaging (MRI). Another modality, optical coherence tomography (OCT), has been under investigation more recently. This review aims to provide an overview of the literature and summarize the usage of USG, MRI, and OCT in evaluating health and pathology of periodontal and peri-implant tissues. Clinical studies have shown that USG could accurately measure gingival height and crestal bone level, and classify furcation involvement. Due to physical constraints, USG may be more applicable to the buccal surfaces of the dentition even with an intra-oral probe. Clinical studies have also shown that MRI could visualize the degree of soft-tissue inflammation and osseous edema, the extent of bone loss at furcation involvement sites, and periodontal bone level. However, there was a lack of clinical studies on the evaluation of peri-implant tissues by MRI. Moreover, an MRI machine is very expensive, occupies much space, and requires more time than cone-beam computed tomography (CBCT) or intraoral radiographs to complete a scan. The feasibility of OCT to evaluate periodontal and peri-implant tissues remains to be elucidated, as there are only preclinical studies at the moment. A major shortcoming of OCT is that it may not reach the bottom of the periodontal pocket, particularly for inflammatory conditions, due to the absorption of near-infrared light by hemoglobin. Until future technological breakthroughs finally overcome the limitations of USG, MRI and OCT, the practical imaging modalities for routine diagnostics of periodontal and peri-implant tissues remain to be plain radiographs and CBCTs.

Exploring the role of innate lymphoid cells in the periodontium: insights into immunological dynamics during orthodontic tooth movement.

Background: The periodontal ligament (PDL) experiences considerable mechanical stresses between teeth and bone, vital for tissue adaptation, especially in orthodontic tooth movement (OTM). While recent research emphasizes the role of innate lymphoid cells (ILCs) in regulating sterile inflammation, their involvement in periodontal tissues during OTM remains largely unexplored. Methods: In this study, PDL tissues from orthodontic patients (n = 8) were examined using flow cytometry to detect ILC subtypes. Transwell co-culture systems were used to expose PDL cells to mechanical strain, followed by measuring migration and ratios of sorted ILC subtypes. Statistical analyses were conducted using paired Student's t-test, Kruskal-Wallis test, Dunn's post-test and one-way/two-way ANOVA with Tukey's post-test (p≤ 0.05; **, p≤ 0.01; ***, p≤ 0.001). Results: Our findings demonstrate a significant increase in CD127+ CD161+ ILC frequencies in PDL tissues during OTM, indicating ILC involvement in sterile inflammation induced by orthodontic forces. Co-culture assays show directed migration of ILC subsets towards PDL cells and substantial proliferation and expansion of ILCs. Conclusions: This study is the first to comprehensively investigate the role of ILCs in sterile inflammation during OTM, revealing their presence and distribution within PDL tissues' innate immune response in vivo, and exploring their migratory and proliferative behavior in vitro. The results suggest a crosstalk between ILCs and PDL cells, potentially influencing the inflammatory response and tissue remodeling processes associated with OTM.

Extracellular Matrix Remodelling of the Periodontium under Orthodontic Force.

As the biological mechanisms of orthodontic tooth movement have been explored further, scholars have gradually focused on the remodelling mechanism of the extracellular matrix (ECM) in the periodontal ligament (PDL). The ECM of the PDL consists of various types of collagens and other glycoproteins. The specific process and mechanism of ECM remodelling during orthodontic tooth movement remains unclear. Collagen I and III, which constitute major components of the PDL, are upregulated under orthodontic force. The changes in the contents of ECM proteins also depend on the expression of ECM-related enzymes, which organise new collagen fibre networks to adapt to changes in tooth position. The matrix metalloproteinase family is the main enzyme that participates in collagen hydrolysis and renewal and changes its expression under orthodontic force. Moreover, ECM adhesion molecules, such as integrins, are also regulated by orthodontic force and participate in the dynamic reaction of cell adhesion and separation with the ECM. This article reviews the changes in ECM components, related enzymes and adhesion molecules in the PDL under orthodontic force to lay the foundation for the exploration of the regulatory mechanism of ECM remodelling during orthodontic tooth movement.

Developments in Alloplastic Bone Grafts and Barrier Membrane Biomaterials for Periodontal Guided Tissue and Bone Regeneration Therapy.

Periodontitis is a serious form of oral gum inflammation with recession of gingival soft tissue, destruction of the periodontal ligament, and absorption of alveolar bone. Management of periodontal tissue and bone destruction, along with the restoration of functionality and structural integrity, is not possible with conventional clinical therapy alone. Guided bone and tissue regeneration therapy employs an occlusive biodegradable barrier membrane and graft biomaterials to guide the formation of alveolar bone and tissues for periodontal restoration and regeneration. Amongst several grafting approaches, alloplastic grafts/biomaterials, either derived from natural sources, synthesization, or a combination of both, offer a wide variety of resources tailored to multiple needs. Examining several pertinent scientific databases (Web of Science, Scopus, PubMed, MEDLINE, and Cochrane Library) provided the foundation to cover the literature on synthetic graft materials and membranes, devoted to achieving periodontal tissue and bone regeneration. This discussion proceeds by highlighting potential grafting and barrier biomaterials, their characteristics, efficiency, regenerative ability, therapy outcomes, and advancements in periodontal guided regeneration therapy. Marketed and standardized quality products made of grafts and membrane biomaterials have been documented in this work. Conclusively, this paper illustrates the challenges, risk factors, and combination of biomaterials and drug delivery systems with which to reconstruct the hierarchical periodontium.

Effect of impacted mandibular third molar extraction on periodontal microbiota and clinical parameters of adjacent teeth: A randomized clinical trial.

It is urgently necessary to clarify the effect of extraction of impacted mandibular third molar (IMTM) on the periodontal tissue of adjacent second molars (ASMs). In this study, the ASM periodontal condition and pathogenic microbes were assessed before IMTM extraction and at 1, 4, 8 and 12 weeks postoperatively. Based on the inclusion and exclusion criteria, our study revealed that IMTM extractions adversely affected distal － periodontal probing depth (dPPD), attachment loss (dAL), plaque index (dPLI) and bleeding on probing (dBOP) within 8 weeks, but these indices gradually normalize after 12 weeks. The subgingival pathogens near the ASMs distal surface, Porphyromonas and Pseudomonas, were significantly increased postoperatively. Moreover, relevance of ASMs clinical indices and subgingival microbes after IMTM extractions was found. In contrast to the situation in chronic periodontitis, the effects of IMTM extraction on dPPD, dAL, dPLI and dBOP of ASMs were mainly correlated with Pseudomonas. Additionally, while the IMTM extractions have adverse distal periodontal indices of ASMs within 8 weeks and increase subgingival pathogens, the modified triangular flap (MTF) had fewer distal periodontal indices and less Pseudomonas. Compared to the traditional envelope flap and triangular flap, the MTF benefits the periodontal health, which could be considered as the priority option for IMTM extractions.

Effect of Deep Margin Elevation on the Pulpal and Periodontal Health of Teeth: A Systematic Review.

OBJECTIVE: To systematically evaluate the clinical performance of deep margin elevation (DME) technique in terms of pulpal and periodontal health of teeth. METHODS AND MATERIALS: An exploratory search was performed in PubMed, Scopus, Embase, Web of Science, and Google Scholar up to September 2023 by two authors independently. This systematic review was performed in accordance with Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Systematic Reviews (PRISMA-SR) and registered with PROSPERO-CRD42022382082. A custom-designed spreadsheet was used to extract the data. The quality of each study was evaluated by means of the Joanna Briggs Institute (JBI) risk of bias (ROB) tool specific for each study design. RESULTS: A total of 5363 articles was obtained through an electronic database search, the grey literature, and a hand search. 2814 duplicates were removed, and an additional 2535 articles were also removed, as they did not meet the eligibility criteria. Following the screening of titles and abstracts, 16 articles were selected for full text reading, from which 10 articles were included for final qualitative analysis. DME was predominantly done with resin-based composite or glass ionomer cement (GIC). Parameters like periodontal pocket depth and bleeding on probing were within normal limits in all teeth with DME. Only one study checked the histological outcome and concluded that DME had no negative effect on the periodontium. Most of the studies used indirect restoration (composite/lithium disilicate/Emax) over the DME layer. The follow-up period ranged between 6 months and 12 years. CONCLUSION: The level of evidence of this review is low, but DME was successful in all teeth, without any deleterious effect on pulp and periodontium.

[Assessment of the condition of organs and tissues of the oral cavity in people with dentition defects against the background of metabolic syndrome]. / Otsenka sostoyaniya organov i tkanei rta u lits s defektami zubnykh ryadov na fone metabolicheskogo sindroma.

OBJECTIVE: The aim of the study is comparative analysis of the condition of oral organs and tissues in people with metabolic syndrome (MS) of varying severity before orthopedic dental rehabilitation based on dental implants. MATERIAL AND METHODS: 255 patients (151 women and 104 men) aged from 35 to 65 years were examined. 3 groups were formed: 2 study groups and a comparison group. Groups 1 and 2 included individuals with excess body weight and MS. The control group consisted of 88 people without MS. An index assessment of the condition of the periodontium and tissue structures of the alveolar bone (according to cone-beam computed tomography), microcirculation in the gingival mucosa was carried out using laser Doppler flowmetry. RESULTS: The analysis of the periodontal condition indicators showed that in all groups of patients with MS, periodontal pathology occurred, the value of which was significantly higher than in patients of the control group (p <0.05). The analysis of bone tissue according to CBCT data showed that the most favorable conditions (type 1 and type 2 of bone according to Misch) for dental implantation are found in people without MS, respectively 3.5% and 35.1% of cases. The intensity of blood flow (σ) was 21.2% lower in group 1 and 48% in group 2, compared with the control group. Vasomotor activity (Kv) was 13.2% lower in the first group and 35% lower in the second group. A decrease in amplitudes in the area of all rhythms in the LDF gram was found: low-frequency - by 15.6%, high-frequency - by 16.9%, pulse - by 3.6%. CONCLUSION: Changes occurring in the organs and tissues of the mouth against the background of MS of varying severity lead to a decrease in tissue perfusion with blood and blood flow activity, a local decrease in bone density, and as a result, pathological changes in periodontal tissues. Before performing dental rehabilitation, it is necessary to take into account all the risks of possible complications caused by the general condition of organs and systems of people with MS.

Single-cell and spatially resolved interactomics of tooth-associated keratinocytes in periodontitis.

Periodontitis affects billions of people worldwide. To address relationships of periodontal niche cell types and microbes in periodontitis, we generated an integrated single-cell RNA sequencing (scRNAseq) atlas of human periodontium (34-sample, 105918-cell), including sulcular and junctional keratinocytes (SK/JKs). SK/JKs displayed altered differentiation states and were enriched for effector cytokines in periodontitis. Single-cell metagenomics revealed 37 bacterial species with cell-specific tropism. Fluorescence in situ hybridization detected intracellular 16 S and mRNA signals of multiple species and correlated with SK/JK proinflammatory phenotypes in situ. Cell-cell communication analysis predicted keratinocyte-specific innate and adaptive immune interactions. Highly multiplexed immunofluorescence (33-antibody) revealed peri-epithelial immune foci, with innate cells often spatially constrained around JKs. Spatial phenotyping revealed immunosuppressed JK-microniches and SK-localized tertiary lymphoid structures in periodontitis. Here, we demonstrate impacts on and predicted interactomics of SK and JK cells in health and periodontitis, which requires further investigation to support precision periodontal interventions in states of chronic inflammation.

Bacteria of healthy periodontal tissues as candidates of probiotics: a systematic review.

OBJECTIVES: The use of probiotics could promote the balance of the subgingival microbiota to contribute to periodontal health. This study aimed to identify the potential of bacteria commonly associated with healthy periodontal tissues as probiotic candidates. MATERIAL AND METHODS: A systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines using the PubMed, Scopus, Science Direct, ProQuest, and Ovid databases as well as the combination of Medical Subject Headings (MeSH) and non-MeSH terms. Based on the selection criteria, original studies published in English and identifying the microorganisms present in the periodontium of healthy individuals and patients with periodontitis using the high-throughput 16S ribosomal gene sequencing technique were included. RESULTS: Out of 659 articles, 12 met the criteria for this review. These articles were published from 2012 to 2020 and mainly originated from the United States, China, and Spain. Most of these studies reported adequate criteria for selecting participants, using standardized clinical criteria, and compliance with quality based on the tools used. In periodontal healthy tissue were identified species like Actinomyces viscosus, Actinomyces naeslundii, Haemophilus parainfluenzae, Rothia dentocariosa, Streptococcus sanguinis, Streptococcus mitis, Streptococcus oralis, Streptococcus gordonii, Streptococcus intermedius, and Prevotella nigrescens which have recognized strains with a capacity to inhibit periodontopathogens. CONCLUSIONS: S. sanguinis, S. oralis, S. mitis, and S. gordonii are among the bacterial species proposed as potential probiotics because some strains can inhibit periodontopathogens and have been reported as safe for humans.

[Evaluation of the photodynamic effect on the state of microcirculation and oxygenation in periodontal tissues in the treatment of chronic generalized periodontitis]. / Otsenka fotodinamicheskogo vozdeistviya na sostoyanie mikrotsirkulyatsii i oksigenatsii v tkanyakh parodonta pri lechenii khronicheskogo generalizovannogo parodontita.

OBJECTIVE: Increasing the effectiveness of treatment of chronic generalized periodontitis using PDT based on clinical and functional substantiation of the effects of a photosensitizer. MATERIALS AND METHODS: A clinical and functional study and treatment of moderate chronic generalized periodontitis was carried out in 62 people (26 men and 36 women) aged from 35 to 55 years without a somatic model with an orthognathic occlusion diagnosed according to ICD-10 - K05.3. Of these, 2 groups were divided depending on the type of treatment: Group 1 (main) - patients with moderate chronic generalized periodontitis - 32 people. (17 men and 15 women, average age of the group - 43.2±2.2 years); Group 2 (control) - patients with moderate chronic generalized periodontitis - 30 people. (14 men and 16 women, average age of the group - 44.0±3.3 years). Complex treatment consisted of sanitation of the mouth, removal of dental plaque and curettage of periodontal pockets in group 1, followed by PDT with Revixan gel using a special wired aligner REVIXAN DENTAL LED (16 r). The clinical condition of the periodontium was assessed using the Greene Vermillion Hygienic Index (OHI-S), the Mühlleman Bleeding Index (SBI) modified by Cowell, and the periodontal index PI. To study the state of microcirculation in the gum tissue, the laser Doppler flowmetry (LDF) method was used using the LAKK-M device (NPP «Lazma¼, Russia). The state of microcirculation was assessed by the microcirculation index (M), which characterizes the level of tissue blood flow; parameter - «σ¼, which determines the fluctuation of the erythrocyte flow. According to Wavelet analysis of LDF-grams, the shunt index (SH) of blood flow was determined. In the «LDF + spectrometry¼ mode, oxygenation in periodontal tissues was studied using optical tissue oximetry (OTO), based on the results of which the perfusion saturation index (Sm) and the specific oxygen consumption index (U, %) were determined. RESULTS: According to LDF data, after PDT (group 1), normalization of clinical indices and the level of microcirculation in periodontal tissues was established, which was accompanied by an increase in the level of blood flow (M) and its activity (σ), which persisted after 3 and 6 months. after PDT. The perfusion saturation index (Sm) and specific oxygen consumption (U) increased more significantly after PDT, which persisted after 3 and 6 months. In the control group, the dynamics of indicators was less pronounced. CONCLUSION: The use of PDT with Revixan gel normalizes the clinical condition of the periodontium, indicators of microhemodynamics and oxygen metabolism.

Insights and Advancements in Periodontal Tissue Engineering and Bone Regeneration.

The regeneration of periodontal bone defects continues to be an essential therapeutic concern in dental biomaterials. Numerous biomaterials have been utilized in this sector so far. However, the immune response and vascularity in defect regions may be disregarded when evaluating the effectiveness of biomaterials for bone repair. Among several regenerative treatments, the most recent technique of in situ tissue engineering stands out for its ability to replicate endogenous restorative processes by combining scaffold with particular growth factors. Regenerative medicine solutions that combine biomaterials/scaffolds, cells, and bioactive substances have attracted significant interest, particularly for bone repair and regeneration. Dental stem cells (DSCs) share the same progenitor and immunomodulatory properties as other types of MSCs, and because they are easily isolable, they are regarded as desirable therapeutic agents in regenerative dentistry. Recent research has demonstrated that DSCs sown on newly designed synthetic bio-material scaffolds preserve their proliferative capacity while exhibiting increased differentiation and immuno-suppressive capabilities. As researchers discovered how short peptide sequences modify the adhesion and proliferative capacities of scaffolds by activating or inhibiting conventional osteogenic pathways, the scaffolds became more effective at priming MSCs. In this review, the many components of tissue engineering applied to bone engineering will be examined, and the impact of biomaterials on periodontal regeneration and bone cellular biology/molecular genetics will be addressed and updated.

LIM homeobox 8 reduced apoptosis and promoted periodontal tissue regeneration function of dental pulp stem cells.

Stem cell-mediated tissue regeneration is a promising strategy for repairing tissue defects and functional reconstruction in periodontitis, a common disease that leads to the loss of alveolar bone and teeth. However, stem cell apoptosis, widely observed during tissue regeneration, impairs its efficiency. Therefore, the regulation of stem cell apoptosis is critical for improving regeneration efficiency. The LIM homeobox 8 gene LHX8, belongs to the LIM homeobox family, which was involved in tooth morphogenesis. Here, we found that LHX8 was significantly expressed in dental pulp. LHX8 knockdown significantly increased dental pulp mesenchymal stem cells (DPSCs) apoptosis, as confirmed by RT-PCR, western blotting, flow cytometry, and transmission electron microscopy. Additionally, LHX8 overexpression inhibited apoptosis and enhanced the osteo/odontogenic differentiation potential of hDPSCs in vitro. Furthermore, LHX8-overexpression could enhance the periodontal tissue regeneration efficiency of hDPSCs in mice with periodontitis. In conclusion, the present study indicates that LHX8 inhibits stem cell apoptosis and promotes functional tissue formation in stem cell-based tissue regeneration engineering, suggesting a new therapeutic target to increase the efficacy of periodontal tissue regeneration.

Identification of a new genetic variant (G231N, E232T, N235D) of peptidylarginine deiminase from P. gingivalis in advanced periodontitis.

Chronic periodontitis (CP), an inflammatory disease of periodontal tissues driven by a dysbiotic subgingival bacterial biofilm, is also associated with several systemic diseases, including rheumatoid arthritis (RA). Porphyromonas gingivalis, one of the bacterial species implicated in CP as a keystone pathogen produces peptidyl arginine deiminase (PPAD) that citrullinates C-terminal arginine residues in proteins and peptides. Autoimmunity to citrullinated epitopes is crucial in RA, hence PPAD activity is considered a possible mechanistic link between CP and RA. Here we determined the PPAD enzymatic activity produced by clinical isolates of P. gingivalis, sequenced the ppad gene, and correlated the results with clinical determinants of CP in patients from whom the bacteria were isolated. The analysis revealed variations in PPAD activity and genetic diversity of the ppad gene in clinical P. gingivalis isolates. Interestingly, the severity of CP was correlated with a higher level of PPAD activity that was associated with the presence of a triple mutation (G231N, E232T, N235D) in PPAD in comparison to W83 and ATCC 33277 type strains. The relation between mutations and enhanced activity was verified by directed mutagenesis which showed that all three amino acid residue substitutions must be introduced into PPAD expressed by the type strains to obtain the super-active enzyme. Cumulatively, these results may lead to the development of novel prognostic tools to assess the progress of CP in the context of associated RA by analyzing the ppad genotype in CP patients infected with P. gingivalis.