Vascular Changes and Hypoxia in Periodontal Disease as a Link to Systemic Complications

Diabetic Retinopathy and Periodontitis: Implications from a Systematic Review and Meta-Analysis

BACKGROUND

Diabetes mellitus, a chronic metabolic disorder affecting millions worldwide, is associated with microvascular complications, including diabetic retinopathy (DR) and periodontitis. Understanding their interrelationship is crucial for comprehensive patient care.

OBJECTIVE

This systematic review and meta-analysis aim to investigate the association between DR and periodontitis in patients with Type 1 and Type 2 diabetes.

METHODOLOGY

Using the PECO framework, we searched PubMed/MEDLINE, Scopus, EMBASE, Google Scholar, and Web of Science databases (Inception to April 2023) for studies on the association between DR and periodontitis. Ten studies (n = 1828 participants), including observational and cross-sectional studies, met the inclusion criteria. We conducted qualitative synthesis, risk of bias analysis using the ROBINS-E tool, Grading of Recommendations, Assessment, Development, and Evaluations assessment (GRADE), and random-effects meta-analysis.

RESULTS

Eight studies found a significant association between severe periodontitis (pocket depth ≥5 mm) and DR, while two found no association. Meta-analysis of 843 participants showed diabetics with periodontitis had 4.48 times higher odds (95% confidence interval: 1.67-12.07, P = .003) of developing retinopathy compared to diabetics without periodontitis. High heterogeneity was observed (I2 = 86%). Subgroup analysis by diabetes type showed no significant difference. The overall GRADE level of evidence was very low.

CONCLUSION

While most included studies suggest an association between severe periodontitis and increased DR risk, the overall certainty of evidence is low. These findings highlight the potential importance of periodontal health in diabetic patients. High-quality longitudinal studies with adequate control of confounders are required to determine if periodontitis contributes to the progression of DR or if the conditions are merely coincidentally related.

Tetrahedral DNA Nanostructure-Modified Nanocoating for Improved Bioaffinity and Osseointegration of Titanium

Titanium (Ti) is extensively used in the medical field because of its excellent biomechanical properties; however, how to precisely fabricate Ti surfaces at a nanoscale remains challenging. In this study, a DNA nanocoating system to functionalize Ti surfaces via a series of sequential reactions involving hydroxylation, silanization, and click chemistry is developed. Tetrahedral DNA nanostructures (TDNs) of two different sizes (≈7 and 30 nm) are assembled and characterized for subsequent surface attachment. In vitro and in vivo assays demonstrated significantly enhanced cell adhesion, spreading, proliferation, osteogenesis, and osseointegration on Ti surfaces modified with 30-nm TDNs, compared to slightly improved effects with 7-nm TDNs. Mechanistic studies showed that the focal adhesion pathway contributed to the enhanced bioaffinity of the 30-nm TDNs, as evidenced by the upregulated expression of vinculin and activation of the Akt signaling pathway. Moreover, under inflammatory or hypoxic conditions, Ti surfaces modified with 30-nm TDNs maintained excellent cellular performance comparable to that under normal conditions, suggesting a broader adaptability for DNA nanoparticles. Thus, better performance is achieved following modification with 30-nm TDNs. In summary, the proposed DNA-guided nanocoating system provides a novel and efficient strategy for the surface nanofabrication of Ti.

Secretomes of Gingival Fibroblasts From Periodontally Diseased Tissues: A Proteomic Analysis

OBJECTIVE

Cell secretomes represent a promising strategy for periodontal and bone regeneration. The objective of this study was to characterize the secretome of human gingival fibroblasts (GF) from periodontally diseased tissues (GF-perio) using proteomics.

MATERIALS AND METHODS

Conditioned media of GF-perio from periodontitis patients (n = 6, 48-h serum-free culture) were subjected to liquid chromatography with tandem mass spectrometry. Global profiles, differentially expressed proteins (DEPs), and functional/gene-set enrichment (FEA) were analyzed using bioinformatics. Selected bone regeneration-related proteins were additionally measured using a multiplex immunoassay. Conditioned media of GF from periodontally healthy subjects were used as a reference.

RESULTS

Overall, 1833 proteins were detected in GF-perio secretomes, including several growth factors, cytokines, chemokines, and extracellular matrix proteins important for wound healing and regeneration. Key bone-related cytokines (FGF2, MCP1, GPNMB, MMP2, IL6, IL8) were confirmed by an immunoassay. Compared to the reference group, 127 exclusive proteins and 73 DEPs (p < 0.05) were identified in the GF-perio group. FEA revealed significant enrichment of "exosome" and "cytoplasm" related cellular components in GF-perio secretomes.

CONCLUSION

The secretome of GF from periodontally diseased tissues may hold therapeutic potential, with several proteins important for wound healing and regeneration, especially those related to exosome functions.

Advances in periodontal healing biomarkers

Periodontitis is the infectious-inflammatory disease of tooth-supporting tissues. Periodontal treatment, either non-surgical or surgical, aims to remove infection, reduce inflammation, eliminate tissue loss, and gain clinical attachment. Clinical and radiographic recordings are widely used and accepted as gold-standard methods in periodontal diagnostics. While these traditional methods allow clinicians to monitor and diagnose periodontitis, they cannot be used to estimate the course of periodontal healing, or predict the disease recurrence or estimate the treatment outcome. Early prediction of the long-term consequences of periodontal treatment would be a crucial and valuable information not only for the clinicians, but also for the patients. Rapid advancements during past few decades boosted the periodontal biomarker studies and various microbe- or host-derived biochemical markers have been suggested as diagnostic biomarkers of periodontitis. Yet, there is no consensus regarding the accuracy of diagnostic biomarkers to monitor treatment response or to predict prognosis. The aim of this chapter will be to describe the healing patterns of periodontal tissues after treatment and present the available evidence on biomarkers that can indicate or predict successful treatment outcomes.

Periodontal pathogens and obesity in the context of cardiovascular risks across age groups

Background

Cardiovascular diseases (CVDs) are the leading cause of mortality and morbidity among noncommunicable diseases. Over the past decade, there has been a notable increase in the prevalence of CVDs among young individuals. Obesity, a well-known risk factor for CVDs, is also associated with various comorbidities that may contribute to cardiovascular risk. The relationship between periodontal pathogens and CVD risk factors, including obesity, smoking, lipid metabolism disorders, and inflammatory markers, remains underexplored.

Methods

This study examined the relationship between six periodontal pathogens (Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, Treponema denticola, Tannerella forsythia, Prevotella intermedia, and Fusobacterium nucleatum) and CVD risk factors among 189 subjects stratified by age and body mass index (BMI). Body composition was assessed via bioimpedance analysis, and blood samples were analyzed for lipid profiles, glucose, and proinflammatory cytokines. Oral samples were collected for polymerase chain reaction (PCR) analysis to identify periodontal pathogens. Cardiovascular and diabetes risk scores were calculated using the SCORE and FINDRISC scales.

Results

The prevalence of periodontal pathogens in the population was 33.0% for P. gingivalis, 47.8% for P. intermedia, 63.4% for A. actinomycetemcomitans, 46.6% for T. forsythia, 46.6% for T. denticola, and 89.2% for F. nucleatum. Significant age- and BMI-related differences were observed in pathogen prevalence, particularly with P. gingivalis, P. intermedia, and T. denticola. Young obese individuals exhibited a higher prevalence of P. intermedia and T. forsythia. P. gingivalis was found to be associated with hypertension and dyslipidemia, while P. intermedia was linked to hypertension and obesity. T. denticola was associated with obesity, dyslipidemia and smoking, whereas T. forsythia was linked to dyslipidemia alone.

Conclusions

This study highlights the potential connection between periodontal pathogens and risk factors associated with cardiovascular disease, including smoking, elevated BMI, increased adipose tissue, hypertension, and dyslipidemia. Further research is required to determine the causal relationships between oral microbiome dysbiosis, obesity and, systemic diseases and to develop an effective strategy for preventing oral health-related CVD risk factors in young adults.

Microfluidic organ-on-chip systems for periodontal research: advances and future directions

Advances in tissue engineering and microfluidic technologies have enabled the development of sophisticated in vitro models known as organ-on-a-chip (OoC) or microphysiological systems. These systems enable to potential to simulate the dynamic interactions between host tissues and their microenvironment including microbes, biomaterials, mechanical forces, pharmaceutical, and consumer-care products. These fluidic technologies are increasingly being utilized to investigate host-microbe and host-material interactions in oral health and disease. Of interest is their application in understanding periodontal disease, a chronic inflammatory condition marked by the progressive destruction of periodontal tissues, including gingiva, periodontal ligament, and alveolar bone. The pathogenesis of periodontal disease involves a complex interplay between microbial dysbiosis and host immune responses, which can lead to a loss of dental support structures and contribute to systemic conditions such as cardiovascular disease, diabetes, and inflammatory bowel disease. This provides a comprehensive overview of the latest developments in millifluidic and microfluidic systems designed to emulate periodontal host-microbe and host-material interactions. We discuss the critical engineering and biological considerations in designing these platforms, their applications in studying oral biofilms, periodontal tissue responses, and their potential to unravel disease mechanisms and therapeutic targets in periodontal disease.

Cellulose Acetate Butyrate-Based In Situ Gel Comprising Doxycycline Hyclate and Metronidazole

Cellulose acetate butyrate is a biodegradable cellulose ester bioplastic produced from plentiful natural plant-based resources. Solvent-exchange-induced in situ gels are particularly promising for periodontitis therapy, as this dosage form allows for the direct delivery of high concentrations of antimicrobial agents to the localized periodontal pocket. This study developed an in situ gel for periodontitis treatment, incorporating a combination of metronidazole and doxycycline hyclate, with cellulose acetate butyrate serving as the matrix-forming agent. Consequently, assessments were conducted on the physicochemical properties, gel formation, drug permeation, drug release, morphological topography, and antimicrobial activities of the formulation. The formulation demonstrated an increased slope characteristic of Newtonian flow at higher bioplastic concentrations. The adequate polymer concentration facilitated swift phase inversion, resulting in robust, solid-like matrices. The mechanical characteristics of the transformed in situ gel typically exhibit an upward trend as the polymer concentration increased. The utilization of sodium fluorescein and Nile red as fluorescent probes effectively tracked the interfacial solvent-aqueous movement during the phase inversion of in situ gels, confirming that the cellulose acetate butyrate matrix delayed the solvent exchange process. The initial burst release of metronidazole and doxycycline hyclate was minimized, achieving a sustained release profile over 7 days in in situ gels containing 25% and 40% cellulose acetate butyrate, primarily governed by a diffusion-controlled release mechanism. Metronidazole showed higher permeation through the porcine buccal membrane, while doxycycline hyclate exhibited greater tissue accumulation, both influenced by polymer concentration. The more highly concentrated polymeric in situ gel formed a uniformly porous structure. Metronidazole and doxycycline hyclate-loaded in situ gels showed synergistic antibacterial effects against S. aureus and P. gingivalis. Over time, the more highly concentrated polymeric in situ gel showed superior retention of antibacterial efficacy due to its denser cellulose acetate butyrate matrix, which modulated drug release and enhanced synergistic effects, making it a promising injectable treatment for periodontitis, particularly against P. gingivalis.

Maternal Salivary miR-423-5p Is Linked to Neonatal Outcomes and Periodontal Status in Cardiovascular-High-Risk Pregnancies

Periodontal disease (PD) during pregnancy may trigger systemic inflammation, increasing the risk of developing cardiometabolic disease (CMD). As a consequence, PD may result in the activation of cellular and molecular pathways, affecting the disease course and pregnancy outcome. Although microRNAs (miRNAs) are considered ideal biomarkers for many diseases, few studies have investigated salivary miRNAs and their role in pregnancy or neonatal outcomes. In this study, we sought to investigate the associations between salivary miRNAs of pregnant women with oral diseases and their effects on neonatal outcomes. Eleven (n = 11) salivary miRNAs from a cohort of pregnant women with oral diseases (n = 32; oral health, H; gingivitis, G; and periodontitis, P) were detected using a previous profiling analysis with an FDR < 0.20 and a fold change (FC) < 0.5 or FC > 2 for the most highly expressed miRNAs. Spearman correlations were performed for 11 salivary microRNAs associated with oral-derived inflammation, which could affect neonatal outcomes during pregnancies at risk for cardiometabolic disease (CMD), defined by the presence of a high pregestational BMI. In addition, ROC curves demonstrated the diagnostic accuracy of the markers used. Upregulation of miR-423-5p expression and a decrease in miR-27b-3p expression were detected in the P-group (p < 0.05), and ROC analysis revealed the diagnostic accuracy of miR-423-5p for discriminating oral diseases, such as gingivitis versus periodontitis (P vs. G, AUC = 0.78, p < 0.05), and for discriminating it from the healthy oral cavity (P vs. H, AUC = 0.9, p < 0.01). In addition, miR-27b-3p and miR-622 were also able to discriminate the healthy group from the P-group (AUC = 0.8, p < 0.05; AUC = 0.8, p < 0.05). miR-483-5p was able to discriminate between the G-group (AUC = 0.9, p < 0.01) and the P-group (AUC = 0.8, p < 0.05). These data support the role of salivary miRNAs as early biomarkers for neonatal outcomes in pregnant women with periodontal disease at high risk for CMD and suggest that there is cross-talk between salivary miRNAs and subclinical systemic inflammation.

Evaluation of Immunohistochemical Biomarkers in Diabetic Wistar Rats with Periodontal Disease

BACKGROUND

The association of periodontal disease and diabetes is a subject of intense research in terms of etiopathology and treatment options. This research aimed to evaluate the modulation of the local inflammatory status by two natural extracts, curcumin (Cu) and rutin (R), in an experimentally induced diabetes and periodontal disease in Wistar rats.

METHODS

Fifty Wistar albino rats were randomly assigned to five groups: Control (C), Diabetes-associated Periodontal Disease (DP), Diabetes-associated Periodontal Disease treated with Curcumin (DPCu), Diabetes-associated Periodontal Disease treated with Rutin (DPR), and Diabetes-associated Periodontal Disease treated with both Curcumin and Rutin (DPCuR). Gingival samples were collected from all rats, and immunohistochemical markers CD3, CD20, and CD34 were evaluated to assess the local inflammatory infiltrate. Descriptive statistics were applied (SPSS24 Software, Armonk, NY, USA).

RESULTS

Rutin, alone or combined with Curcumin, reduced CD3-positive cell levels. Curcumin demonstrated superior efficacy in reducing CD20-positive cells. The combination of Curcumin and Rutin had the most important impact on both markers. Curcumin notably increased immature CD34-positive cell levels.

CONCLUSIONS

Curcumin and Rutin, either alone or together, hold potential for reducing local inflammation in diabetes-induced periodontal disease in Wistar rats.

Oral Biofilm Composition, Dissemination to Keratinocytes, and Inflammatory Attenuation Depend on Probiotic and Synbiotic Strain Specificity

Several inflammatory diseases are characterized by a disruption in the equilibrium between the host and its microbiome. Due to the increase in resistance, the use of antibiotics for the widespread, nonspecific killing of microorganisms is at risk. Pro-microbial approaches focused on stimulating or introducing beneficial species antagonistic toward pathobionts may be a viable alternative for restoring the host-microbiome equilibrium. Unfortunately, not all potential probiotic or synbiotic species and even subspecies (to strain level) are equally effective for the designated pathology, leading to conflicting accounts of their efficacy. To assess the extent of these species- and strain-specific effects, 13 probiotic candidates were evaluated for their probiotic and synbiotic potential with glycerol on in vitro oral biofilms, dissemination from biofilms to keratinocytes, and anti-inflammatory activity. Species- and strain-specific effects and efficacies were observed in how they functioned as probiotics or synbiotics by influencing oral pathobionts and commensals within biofilms and affected the dissemination of pathobionts to keratinocytes, ranging from ineffective strains to strains that reduced pathobionts by 3 + log. In addition, a minority of the candidates exhibited the ability to mitigate the inflammatory response of LPS-stimulated monocytes. For a comprehensive assessment of probiotic therapy for oral health, a judicious selection of fully characterized probiotic strains that are specifically tailored to the designated pathology is required. This approach aims to challenge the prevailing perception of probiotics, shifting the focus away from "form over function." Rather than using unproven, hypothetical probiotic strains from known genera or species, one should choose strains that are actually functional in resolving the desired pathology before labelling them probiotics.

E. Coli LPS-induced calcium signaling regulates the expression of hypoxia-inducible factor 1α in periodontal ligament fibroblasts in a non-hypoxia-dependent manner

Periodontitis, an inflammatory disease, can cause significant damage to the oral tissues which support the teeth. During the early development of periodontitis, periodontal ligament fibroblasts (PDLFs) undergo metabolic reprogramming regulated by hypoxia-inducible factor 1α (HIF-1α), which is strongly linked to the progression of inflammation. However, the precise mechanisms by which PDLFs regulate HIF-1α and its associated metabolic reprogramming during early inflammation remain unclear. This study illustrated that brief and low-dose exposure to Escherichia coli (E. coli) lipopolysaccharide (LPS) can serve as a non-hypoxic stimulus, effectively replicating early periodontal inflammatory reactions. This is evidenced by the upregulation of HIF-1α expression and the activation of HIF-1α-mediated crucial glycolytic enzymes, namely lactate dehydrogenase a, pyruvate kinase, and hexokinase 2, concomitant with an augmentation in the inflammatory response within PDLFs. We observed that the effects mentioned and their impact on macrophage polarization were notably attenuated when intracellular and extracellular stores of Ca2+ were depleted using BAPTA-AM and Ca2+-free medium, respectively. Mechanistically, our findings demonstrated that the transcriptional process of HIF-1α is regulated by Ca2+ during E. coli LPS stimulation, mediated through the signal transducer and activator of transcription 3 (STAT3) pathway. Additionally, we observed that the stabilization of intracellular HIF-1α proteins occurs via the endothelin (ET)-1-endothelin A receptor pathway, independent of hypoxia. Taken together, our research outcomes underscore the pivotal involvement of Ca2+ in the onset of early periodontitis by modulating HIF-1α and glycolysis, thereby presenting novel avenues for early therapeutic interventions.

Comparative study of oral microbiota in the experimental long-term opioid exposure, after its withdrawal and the use of complex drug correction

OBJECTIVE

Aim: To study changes of dental biofilm microbiota composition during experimental opioid exposure, after its withdrawal and when using of complex drug correction..

PATIENTS AND METHODS

Materials and Methods: Microbiological studies (48 rats) included microscopic and bacteriological methods, as well as determination of antibiotic susceptibility of microbial isolates. Ceftriaxone and pentoxifylline were used to correction the changes.

RESULTS

Results: The action of opioid for 10 weeks caused considerable changes in the microbiocenosis, which was illustrated by a significant increasing of the opportunistic pathogens quantitative indicators and the emergence of pathogenic microbiota. Changes in the microbiocenosis at 6 weeks of opioid exposure and after its withdrawal for 4 weeks were expressed in the appearance of pathogenic microbiota and the absence of significant differences in quantitative indicators of saprophytic and opportunistic microflora compared to similar indicators in animals with 10 weeks opioid exposure. This indicated a slow progression of dysbiotic changes and the inflammatory process in the oral cavity of rats.

CONCLUSION

Conclusions: After 10 weeks of experiment with opioid administration for 6 weeks and the use of ceftriaxone and pentoxifylline on the background of 4-week opioid withdrawal, a significant reduction of quantitative indicators of opportunistic bacteria and elimination of pathogenic species of microorganisms was determined. The use of complex drug correction on the background of 10 weeks of opioid exposure led to a significant reduction in the quantitative indicators of opportunistic pathogens and contributed to the elimination of most pathogenic species of microbiota under the action of ceftriaxone.

Vascular Endothelial Growth Factor A serum levels and common gene polymorphisms in generalized periodontitis affected patients

OBJECTIVE

To evaluate and compare the associations of VEGFA serum levels and SNPs (rs1570360, rs699947, rs3025033, and rs2146323) with periodontitis in study participants grouped by gender.

METHODS

The study enrolled 261 patients with periodontitis and 441 healthy controls as a reference group. Patients underwent periodontal examination and radiographic analysis to confirm the periodontitis diagnosis. Blood samples were collected, and the DNA salting-out method was used for DNA extraction from peripheral venous blood. Genotyping of VEGFA (rs1570360, rs699947, rs3025033, and rs2146323) was performed using real-time polymerase chain reaction (RT-PCR) and serum level analysis was done for 80 individuals - 40 periodontitis-affected patients and 40 reference group subjects.

RESULTS

The analysis of VEGFA (rs1570360, rs699947, rs3025033, and rs2146323) showed that the rs3025033 GG genotype was less frequent in the periodontitis group than in the reference group (1.6% vs. 5.7%,p = 0.008). VEGFA serum levels were not statistically significantly different between periodontitis patients and reference group subjects (554.29 (522.38) ng/ml vs. 581.32 (348.16) ng/ml, p = 0.786). Individuals carrying rs1570360, rs699947, rs3025033, and rs2146323 haplotype A-A-G-A had decreased risks of periodontitis, while rare haplotype of VEGFA (rs1570360, rs699947, rs3025033, and rs2146323) was associated with increased odds of periodontitis (OR= 0.42; 95% CI: 0.20-0.85; p < 0.017; OR= 4.08; 95% CI: 1.86-8.94; p < 0.0001, respectively).

CONCLUSION

The rs3025033 GG genotype and the rs1570360, rs699947, rs3025033, and rs2146323 A-A-G-A haplotypes may play a protective role in the development of periodontitis, but a less common haplotype of the same VEGFA polymorphism may be associated with the risk of developing periodontitis.

Hypoxia dissociates HDAC6/FOXO1 complex and aggregates them into nucleus to regulate autophagy and osteogenic differentiation

OBJECTIVE

This research aimed to elucidate the molecular mechanisms underlying the periodontitis-associated bone loss, with particular emphasis on the contributory role of hypoxic microenvironment in this process.

BACKGROUND

Periodontitis generally causes alveolar bone loss and is often associated with a hypoxic microenvironment, which affects bone homeostasis. However, the regulating mechanism between hypoxia and jaw metabolism remains unclear. Hypoxia triggers autophagy, which is closely related to osteogenic differentiation, but how hypoxia-induced autophagy regulates bone metabolism is unknown. HDAC6 and FOXO1 are closely related to bone metabolism and autophagy, respectively, but whether they are related to hypoxia-induced bone loss and their internal mechanisms is still unclear.

METHODS

Established rat nasal obstruction model and hypoxia cell model. Immunohistochemistry was performed to detect the expression and localization of HDAC6 and FOXO1 proteins, analysis of autophagic flux and transmission electron microscopy was used to examine the autophagy level and observe the autophagosomes, co-immunoprecipitation and chromatin immunoprecipitation were preformed to investigate the interaction of HDAC6 and FOXO1.

RESULTS

Hypoxia causes increased autophagy and reduced osteogenic differentiation in rat mandibles and BMSCs, and blocking autophagy can attenuate hypoxia-induced osteogenic differentiation decrease. Moreover, hypoxia dissociated the FOXO1-HDAC6 complex and accumulated them in the nucleus. Knocking down of FOXO1 or HDAC6 alleviated hypoxia-induced autophagy elevation or osteogenic differentiation reduction by binding to related genes, respectively.

CONCLUSION

Hypoxia causes mandibular bone loss and autophagy elevation. Mechanically, hypoxia dissociates the FOXO1-HDAC6 complex and aggregates them in the nucleus, whereas HDAC6 decreases osteogenic differentiation and FOXO1 enhances autophagy to inhibit osteogenic differentiation.

Catechol-Modified and MnO2-Nanozyme-Reinforced Hydrogel with Improved Antioxidant and Antibacterial Capacity for Periodontitis Treatment

Periodontitis is an inflammatory disease characterized by tooth loss and alveolar bone resorption. Bacteria are the original cause of periodontitis, and excess reactive oxygen species (ROS) encourage and intensify inflammation. In this study, a mussel-inspired and MnO2 NPs-reinforced adhesive hydrogel capable of alleviating periodontitis with improved antibacterial and antioxidant abilities was developed. The hydrogel was created by combining polyvinyl alcohol (PVA), 3,4-dihydroxy-d-phenylalanine (DOPA), and MnO2 nanoparticles (NPs) (named PDMO hydrogel). The hydrogel was demonstrated to be able to scavenge various free radicals (including total ROS─O2•- and OH•) and relieve the hypoxia in an inflammatory microenvironment by scavenging excess ROS and generating O2 due to its superoxide dismutase (SOD)/catalase (CAT)-like activity. Besides, under 808 nm near-infrared (NIR) light, the photothermal performance of the PDMO hydrogel displayed favorable antibacterial and antibiofilm effects toward Escherichia coli, Staphylococcus aureus, and Porphyromonas gingivalis (up to nearly 100% antibacterial rate). Furthermore, the PDMO hydrogel exhibited favorable therapeutic efficacy in alleviating gingivitis in Sprague-Dawley rats, even comparable to or better than the commercial PERIO. In addition, in the periodontitis models, the PDMO2 group showed the height of the residual alveolar bone and the smallest shadow area of low density among other groups, indicating the positive role of the PDMO2 hydrogel in bone regeneration. Finally, the biosafety of the PDMO hydrogel was comprehensively investigated, and the hydrogel was demonstrated to have good biocompatibility. Therefore, the developed PDMO hydrogel provided an effective solution to resolve biofilm recolonization and oxidative stress in periodontitis and could be a superior candidate for local drug delivery system in the clinical management of periodontitis with great potential for future clinical translation.

An In Vitro Study of Local Oxygen Therapy as Adjunctive Antimicrobial Therapeutic Option for Patients with Periodontitis

Periodontitis is a common global disease caused by bacterial dysbiosis leading to tissue destruction, and it is strongly associated with anaerobic bacterial colonization. Therapeutic strategies such as oxygen therapy have been developed to positively influence the dysbiotic microbiota, and the use of oxygen-releasing substances may offer an added benefit of avoiding systemic effects commonly associated with antibiotics taken orally or hyperbaric oxygen therapy. Therefore, the oxygen release of calcium peroxide (CaO₂) was measured using a dissolved oxygen meter, and CaO₂ solutions were prepared by dissolving autoclaved CaO₂ in sterile filtered and deionized water. The effects of CaO₂ on planktonic bacterial growth and metabolic activity, as well as on biofilms of Streptococcus oralis and Porphyromonas gingivalis, were investigated through experiments conducted under anaerobic conditions. The objective of this study was to investigate the potential of CaO₂ as an antimicrobial agent for the treatment of periodontitis. Results showed that CaO₂ selectively inhibited the growth and viability of P. gingivalis (p < 0.001) but had little effect on S. oralis (p < 0.01), indicating that CaO₂ has the potential to selectively affect both planktonic bacteria and mono-species biofilms of P. gingivalis. The results of this study suggest that CaO₂ could be a promising antimicrobial agent with selective activity for the treatment of periodontitis.

Oxygen-Releasing Hyaluronic Acid-Based Dispersion with Controlled Oxygen Delivery for Enhanced Periodontal Tissue Engineering

Periodontitis is a chronic biofilm-associated inflammatory disease of the tooth-supporting tissues that causes tooth loss. It is strongly associated with anaerobic bacterial colonization and represents a substantial global health burden. Due to a local hypoxic environment, tissue regeneration is impaired. Oxygen therapy has shown promising results as a potential treatment of periodontitis, but so far, local oxygen delivery remains a key technical challenge. An oxygen (O₂)-releasing hyaluronic acid (HA)-based dispersion with a controlled oxygen delivery was developed. Cell viability of primary human fibroblasts, osteoblasts, and HUVECs was demonstrated, and biocompatibility was tested using a chorioallantoic membrane assay (CAM assay). Suppression of anaerobic growth of Porphyromonas gingivalis was shown using the broth microdilution assay. In vitro assays showed that the O₂-releasing HA was not cytotoxic towards human primary fibroblasts, osteoblasts, and HUVECs. In vivo, angiogenesis was enhanced in a CAM assay, although not to a statistically significant degree. Growth of P. gingivalis was inhibited by CaO₂ concentrations higher than 256 mg/L. Taken together, the results of this study demonstrate the biocompatibility and selective antimicrobial activity against P. gingivalis for the developed O₂-releasing HA-based dispersion and the potential of O₂-releasing biomaterials for periodontal tissue regeneration.

Cone-beam-computed tomography evaluation of mandibular nutrient canals in patients with periodontal diseases

Background and Aim

The aim of this study was to evaluate radiographically the prevalence of mandibular nutrient canals (NCs) in patients with/without periodontal bone loss with aging and to correlate the number of NCs with the severity of bone loss using cone-beam-computed tomography (CBCT).

Patients and Methods

CBCT examinations of 208 patients were evaluated retrospectively of all patients, 114 had periodontal bone loss, whereas 94 patients were control subjects. Alveolar bone loss investigations were performed according to the Progressive Rate Index.

Results

NCs were observed in 55% of the control group and 86% of the periodontitis patients. NCs were more prevalent in the elderly age group with periodontal bone loss. In the study group, the NCs were statistically more frequent than in the control subjects (P > 0.05).

Conclusion

Statistical analysis showed a significant difference between the age groups and the prevalence of NCs increased in patients with periodontal alveolar bone loss with aging (P < 0.05).

Clinical, Radiographic, and Inflammatory Peri-Implant Parameters around Narrow Diameter Implant Crowns among Prediabetic and Non-Diabetic Subjects

Background and Objectives: To compare the clinical, radiographic, and inflammatory peri-implant parameters around narrow diameter implants (NDI) supported single and splinted crowns in non-diabetics and prediabetes. Materials and Methods: The clinical and radiographic parameters and the levels of IL-6 and TNF-α in the peri-implant crevicular fluid (PICF) of narrow diameter single (NDISCs) and splinted (NDISPs) crown implants were assessed both in non-diabetics and participants with prediabetes. The glycemic state of the patient was assessed using glycated hemoglobin (HbA1c) levels. The peri-implant soft tissue indices (Plaque index (PI), bleeding on probing (BoP), probing depth (PD)) and marginal bone loss were recorded and compared between the groups. Success of the prosthesis was assessed by the frequency of technical complications and patient satisfaction. Inter-group comparison was performed using ANOVA (one-way analysis of variance) while the normal distribution of dependent variables was calculated using Shapiro-Wilk. A p-value of less than 0.05 was considered to be statistically significant. Results: Sixty participants (30 non-diabetics and 30 with prediabetes) with a total of 178 (118 NDISCs and 60 NDISPs) platform-switched NDIs were a part of the study. Of the 118 NDISCs, 56 were placed in the non-diabetic individuals and 62 were placed in the prediabetes group whereas 30 NDISPs each were placed in both the study groups. The clinical parameters of PI, BoP and PD in the single crown and splinted crown groups showed comparable results. However, a statistically significant difference (p-value of less than 0.05) in PI, BoP and PD and in the values of IL-6 and TNF-α was found when a comparison was made between the non-diabetes and prediabetes group. A total of 91% of the patients were satisfied with the esthetics of the implants while 79% of the patients showed satisfaction with function. Conclusions: All the clinical and radiographic parameters were statistically similar in both single and splinted types of narrow diameter implants. However, the bone loss, probing depth, plaque index, and levels of inflammatory markers were statistically higher in prediabetes as compared to non-diabetes implying that a slight hyperglycemic state impacts peri-implant health.

PGC-1 alpha regulates mitochondrial biogenesis to ameliorate hypoxia-inhibited cementoblast mineralization

Hypoxia often occurs in inflammatory tissues, such as tissues affected by periodontitis and apical periodontitis lesions. Mitochondrial biogenesis can be disrupted in hypoxia. Peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1α) is a core factor required for mitochondrial biogenesis. Cementoblasts are root surface lining cells that play an integral role in cementum formation. There is a dearth of research on the effect of hypoxia on cementoblasts and underlying mechanisms, particularly in relation to mitochondrial biogenesis during the hypoxic process. In this study, we found that the expression of hypoxia inducible factor-1α was elevated in apical periodontitis tissues in vivo. In contrast, periapical lesions exhibited a reduction of PGC-1α expression. For in vitro experiments, cobalt chloride (CoCl₂ ) was used to induce hypoxia. We observed that CoCl₂ -induced hypoxia suppressed the mineralization ability and mitochondrial biogenesis of cementoblasts, accompanied by abnormal mitochondria morphology. Furthermore, we found that CoCl₂ blocked the p38 pathway, while it activated the Erk1/2 pathway, with the former upregulating the expression of PGC-1α, while the latter reversed the effects. Overall, our findings demonstrate that mitochondrial biogenesis, especially via PGC-1α, is impaired during cementogenesis in the context of CoCl₂ -induced hypoxia, dependent on the mitogen-activated protein kinase signaling pathway.

A brief review of vitamin D as a potential target for the regulation of blood glucose and inflammation in diabetes-associated periodontitis

Diabetes is a metabolic disorder associated with various complications, including periodontitis. The risk of periodontitis is increased in patients with diabetes, while vitamin D deficiency is associated with both diabetes and periodontitis. Thus, there is a need to identify the molecular effects of vitamin D on the regulation of inflammation and glucose in diabetes-associated periodontitis. The Web of Science, Scopus, and PubMed databases were searched for studies of the molecular effects of vitamin D. Molecular effects were reportedly mediated by salivary secretions, interactions of advanced glycation end products (AGEs) with receptors of AGEs (RAGEs), cytokines, and oxidative stress pathways linking diabetes with periodontitis. Vitamin D supplementation attenuates inflammation in diabetes-associated periodontitis by reducing the levels of inflammatory cytokines and numbers of immune cells; it also has antibacterial effects. Vitamin D reduces cytokine levels through regulation of the extracellular signal-related kinase 1/2 and Toll-like receptor 1/2 pathways, along with the suppression of interleukin expression. Glucose homeostasis is altered in diabetes either because of reduced insulin production or decreased insulin sensitivity. These vitamin D-related alterations of glucoregulatory factors may contribute to hyperglycaemia; hyperglycaemia may also lead to alterations of glucoregulatory factors. This review discusses the pathways involved in glucose regulation and effects of vitamin D supplementation on glucose regulation. Further studies are needed to characterise the effects of vitamin D on diabetes-associated periodontitis.