Aggressive and acute periodontal diseases

Dental management of a young patient with Papillon-Lefèvre syndrome

This report presents the case of a girl in early adolescence with symptoms suggestive of Papillon-Lefèvre syndrome (PLS) who remained undetected with poorly managed periodontitis until the advanced stage of alveolar resorption, leading to multiple tooth loss due to periodontitis. All remaining teeth had grade III mobility and negligible alveolar support, necessitating extraction. Conventional complete dentures were provided for functional and aesthetic rehabilitation. The literature review conducted to evaluate various dental treatment strategies and their outcomes for patients diagnosed with PLS at the deciduous or mixed dentition stage indicates that periodontal debridement with regular supportive periodontal therapy, antibiotic regimens and oral hygiene maintenance reinforcement can preserve teeth until late adolescence.

The effect of photobiomodulation on oral microbiota dysbiosis: A literature review

The balance, or dysbiosis, of the microbial community is crucial for human health and disease. While most microbes are harmless, some can lead to oral infections such as periodontal disease, dental caries, and infections related to Candida biofilms. Conventional treatments, such as mechanical debridement, antibiotics, probiotics, and prebiotics, aim to restore the balance of oral microbiota, but they encounter challenges like microbial resistance and patient compliance issues. To address these problems, laser therapy has emerged as a promising local treatment option. Among the various types of lasers, low-power lasers-specifically low-level laser therapy or photobiomodulation (PBM) therapy-are particularly favored for oral applications due to their antimicrobial effects and non-invasive properties. PBM influences oral microbiota dysbiosis through both direct and indirect pathways. The direct effect occurs when endogenous targets are remained within the cell or released into the colony. In contrast, an indirect effect can result from targets located in the tissues and cells surrounding the bacteria. However, studies using different irradiation protocols have produced varied results. Therefore, this study aims to investigate and review the effects of PBM on oral microbiota dysbiosis and its potential in promoting the maintenance of human health.

Triple-Combination Therapy with a Multifunctional Yolk-Shell Nanozyme Au@CeO2 Loaded with Dimethyl Fumarate for Periodontitis

Periodontitis, a chronic inflammatory disease, is the leading cause of tooth loss in adults and is one of the most prevalent and complex oral conditions. Oxidative stress induced by the excessive generation of reactive oxygen species (ROS) leads to periodontitis, which is closely associated with pathological processes, including mitochondrial dysfunction of periodontal cells and local immune dysregulation. However, current treatment modalities that target single pathological processes have limited long-term therapeutic effects. Herein, a multifunctional Yolk-Shell nanozyme, Au@CeO2-dimethyl fumarate (DMF), which comprehensively addresses the oxidative stress-induced pathophysiological processes of periodontitis through antioxidant activity, mitochondrial maintenance, and immune modulation mechanisms, is described. For material design logic, functionally complementary Au and CeO2 formed an excellent photothermally regulated high-efficiency nanozyme, which also provided an ideal drug carrier for DMF. As for the therapeutic logic, Au@CeO2-DMF restores mitochondrial dysfunction and immune dysregulation, which also contributes to endogenous ROS elimination, thereby achieving long-term stable therapeutic effects. In a rat model, local Au@CeO2-DMF photothermal therapy effectively alleviated ROS-induced tissue damage and restored periodontal homeostasis. Altogether, this study presents a novel antioxidant nanozyme for managing alveolar bone loss under prolonged oxidative stress and demonstrates the importance of comprehensive intervention in key pathological processes in periodontitis treatment design.

Colorimetric analysis of intraoral scans: A novel approach for detecting gingival inflammation

BACKGROUND

Gingivitis, a widely prevalent oral health condition, affects up to 80% of the population. Traditional assessment methods for gingivitis rely heavily on subjective clinical evaluation. This study seeks to explore the efficacy of interpreting the color metrics from intraoral scans to objectively differentiate between healthy and inflamed gingiva.

METHODS

This study used the percentage of bleeding on probing (BOP%) as the clinical reference standard. Intraoral scans, obtained before and after gingivitis treatment using a scanner, were analyzed through a custom MATLAB script to quantify HSV (hue, saturation, value) and CIELAB (Commission Internationale de l'Eclairage L*a*b*) color coordinates. The region of interest was a 2-mm-wide gingival strip along the buccal margin of the maxillary anterior teeth. Linear regression analysis was performed to evaluate the relationship between photometric outcomes and continuous, dichotomous, and categorical BOP data. Diagnostic accuracy was assessed using the area under the receiver operating characteristic (ROC) curve (AUC), as well as sensitivity and specificity measures.

RESULTS

The analysis included clinical and digital color data from 110 scans, adhering to the STROBE (Strengthening the Reporting of Observational Studies in Epidemiology) guidelines. The multilevel linear regression analysis underscored a significant correlation between the BOP% and digital color metrics, specifically the CIELAB a* (red-green chroma), CIELAB b* (yellow-blue chroma), and color saturation, with AUC performances of 70%, 79.5%, and 80.8%, respectively.

CONCLUSION

Digital color analysis of intraoral scans has demonstrated a range of performance from acceptable to excellent in distinguishing sites with BOP. This innovative approach presents a promising tool for dentists and researchers in the accurate diagnosis, screening, and management of gingivitis.

PLAIN LANGUAGE SUMMARY

Our study focuses on finding a better way to detect gingivitis, a common gum disease affecting many people. Traditional methods rely on the dentist's visual inspection, which can be subjective. We explored the use of color measurements from digital intraoral scans to objectively identify healthy versus inflamed gums. We analyzed 110 scans from 55 participants, examining the color differences in the gums before and after treatment. By measuring specific color values, we achieved up to 80.8% accuracy in distinguishing between healthy and inflamed gums. This method could offer a more reliable tool for dentists and researchers to diagnose and manage gingivitis, leading to better oral health outcomes.

Association of RS1126478 (LTF) with molar-incisor and generalized periodontitis

OBJECTIVES

LTF SNP rs1126478 (T>C) could modulate Lactoferrin function and release and has been associated with periodontal disease in different locations before, but not in America. Thus, this study aimed to assess the association between this SNP and Grade C Periodontitis (Generalized (PerioC-G) and Molar Incisor Pattern (PerioC-MIP)) and seek a relationship between its presence and LTF gingival crevicular fluid (GCF) production.

MATERIAL AND METHODS

Oral cells from 361 Brazilians and 375 North Americans patients (Diseased and Health Controls (PH) from both locations) were collected. DNA was extracted, and a prefabricated probe system determined rs116478 genotyping. Immunoenzymatic analysis detected LTF levels in GCF.

RESULTS

Higher allelic altered-C frequency was associated with PerioC. For PerioC-G, CT and CC genotypes presented a frequency of 44.7% and 34.1%, respectively, while 37.3% and 26.4% were found to PH group (OD=2.1 (p=0.004) for CT and OD=2.3 (p=0.003) for CC). PerioC-G was associated with a lower concentration (742.2±717.9 pg/ml) of LTF than PerioC-MIP (5851±5859.2 pg/ml), p<0.0001. Multiple logistic regression showed that CC genotype impacted LTF levels by acting as a predictor (β =2.457, p=0.02, OD=1.17) despite the site or diagnosis.

CONCLUSION

There is an association of rs1126478 with Grade C periodontitis, mainly the PerioC-G. Lower LTF levels in GCF might be associated with the generalized disease pattern.

CLINICAL RELEVANCE

This study assessed and compared the genetic background in two distinct locations, paving the way for new studies regarding personalized risk and treatment for different ethnicities. As this SNP is in a region related to the antimicrobial function of LTF, it could impact PerioC-MIP and PerioC-G response against periodontopathogens. This discovery opens the way for in vitro studies analyzing the functionality of this SNP, and, in the future, it can be used to treat PerioC, individualizing the phenotypes.

Single nucleotide polymorphism rs854560 in paraoxonase-1 regulates the cytodifferentiation of human periodontal ligament cells

Aggressive periodontitis (AgP), classified as Stages III or IV and grade C periodontitis, is characterized by the rapid destruction of periodontal tissue. Genetic factors contribute to the pathogenesis of this disease, and familial aggregation of periodontitis is often observed. However, the mechanisms underlying the onset or progression of AgP have not been elucidated. Previously, we performed exome sequencing and identified AgP risk factors in Japanese AgP-patients. However, the small sample size limited our scope for detecting some of the true AgP genetic risk factors. To overcome this limitation, we searched for AgP-related genes more comprehensively from the whole exome sequencing data of the Japanese AgP-patients by extending the filtering criteria range. We identified seven AgP-associated suggestive genes, including the single nucleotide polymorphism (SNP) rs854560 in paraoxonase-1 (PON-1), which is correlated with AgP. However, the mechanism(s) underlying the induction of AgP pathogenesis by the SNP rs854560 PON-1 has not been elucidated. Thus, we further analyzed the functions of the SNP rs854560 PON-1 in human periodontal ligament (HPDL) cells through transfection of the wild-type PON-1 (WT) or SNP rs854560 PON-1 (mut) into HPDL cells. Real-time PCR indicated that mut had higher mRNA expression of osteogenic related-genes and showed a higher tendency of ALP activity and proliferation. The result suggested that WT PON-1 contributes to periodontal tissue homeostasis through appropriate proliferation and cytodifferentiation of HPDL cells, while SNP rs854560 PON-1 may mediate excessive calcification of periodontal tissue due to hyper proliferation of HPDL cells, thereby increasing the risk of AgP.

A global science mapping analysis on odontogenic infections

OBJECTIVES

Odontogenic infections are common and a topic of core interest for dentists, and maxillofacial surgeons. The aim of this study was to conduct a bibliometric analysis of the global literature on odontogenic infection and explore the top 100 most cited papers to identify the common causes, sequelae and management trends.

METHODS

Following a comprehensive literature search, a list of top 100 most cited papers was created. The VOSviewer software (Leiden University, The Netherlands) was used to create a graphical representation of the data, and statistical analyses were performed to analyze the characteristics of the top 100 most cited papers.

RESULTS

A total of 1,661 articles were retrieved with the first article published in 1947. There is an exponential upward trend on the number of publications (R2 = 0.919) and a majority of papers are in English language (n = 1,577, 94.94%). A total of 22,041 citations were found with a mean of 13.27 per article. The highest number of publications were recorded from developed countries. There was a male predilection in the reported cases and the most common sites included the submandibular and parapharyngeal spaces. Diabetes mellitus was identified as the commonest co-morbidity. Surgical drainage was ascertained to be the preferred method of management.

CONCLUSIONS

Odontogenic infections remain prevalent and have a global distribution. Although prevention of odontogenic infection through meticulous dental care is ideal, early diagnosis and prompt management of established odontogenic infections is important to avoid morbidities and mortality. Surgical drainage is the most effective management strategy. There is lack of consensus regarding the role of antibiotics in the management of odontogenic infections.

LncRNA JHDM1D-AS1 promotes osteogenic differentiation of periodontal ligament cells by targeting miR-532-5p to activate IGF1R signaling

OBJECTIVE

The aim of this study was to explore the mechanism underlying periodontal ligament cells (PDLCs) osteogenic differentiation.

BACKGROUND

Periodontitis causes damage to tooth-supporting apparatus and eventually leads to tooth loss. PDLCs hold great promise in periodontal regeneration due to their osteogenic features.

METHODS

The expression of osteogenic markers, lncRNA JHDM1D-AS1, miR-532-5p and IGF1R was examined. For osteogenic differentiation, primary human PDLCs (hPDLCs) were cultured in an osteogenic medium, and it was assessed by ALP activity and Alizarin Red staining. The interaction between JHDM1D-AS1, miR-532-5p and IGF1R was analyzed via dual luciferase, RIP and RNA pull-down assays.

RESULTS

JHDM1D-AS1 was up-regulated during osteogenic differentiation and its silencing inhibited hPDLC osteogenic differentiation. JHDM1D-AS1 worked as a miR-532-5p sponge in hPDLCs. miR-532-5p directly targeted IGF1R to suppress its expression, and miR-532-5p knockdown facilitated osteogenic differentiation of hPDLCs. Overexpression of IGF1R promoted osteogenic differentiation of hPDLCs via activating Notch/HES1 signaling in hPDLCs.

CONCLUSION

JHDM1D-AS1 promotes osteogenic differentiation of hPDLCs via sponging miR-532-5p to facilitate IGF1R expression and activate Notch/HES1 signaling.

The oral microbiome of a family including Papillon-Lefèvre-syndrome patients and clinically healthy members

AIMS

The oral microbiota composition of patients diagnosed with Papillon-Lefèvre-syndrome and treated for several years were compared to those existing in the oral cavity of the clinically healthy family members and a cohort of patients having various stages of chronic periodontitis.

MATERIALS AND METHODS

A family with two sisters affected with severe periodontitis and with the typical skin symptoms of Papillon-Lefèvre-syndrome, and symptomless parents and third sibling were investigated. The Patients received periodontal treatment for several years and their oral microbiome was analysed by amplicon sequencing. Data were evaluated by microbial cluster analysis.

RESULTS

The microbiome of the patients with Papillon-Lefèvre-syndrome was predominated with Aggregatibacter actinomycetemcomitans and associated oral periodontopathogens. Although the clinically healthy family members showed no oral disorder, their microbiome resembled that of subjects having mild periodontitis.

CONCLUSIONS

Predominance of A. actinomycetemcomitans in the subgingival microbiome of patients with Papillon-Lefèvre-syndrome suggests that specific treatment strategies directed against this pathobiont may improve the oral health status of the affected individuals.

TRIAL REGISTRATION

The study was conducted in accordance with the Declaration of Helsinki and the ethical permission has been issued by the Human Investigation Review Board of the University of Szeged, Albert Szent-Györgyi Clinical Centre (Permission No. 63/2017-SZTE). September 19, 2017.  https://u-szeged.hu/klinikaikutatas/rkeb-altal-jovahagyott/rkeb-2017 .

Periodontitis promotes bacterial extracellular vesicle-induced neuroinflammation in the brain and trigeminal ganglion

Gram-negative bacteria derived extracellular vesicles (EVs), also known as outer membrane vesicles, have attracted significant attention due to their pathogenic roles in various inflammatory diseases. We recently demonstrated that EVs secreted by the periodontopathogen Aggregatibacter actinomycetemcomitans (Aa) can cross the blood-brain barrier (BBB) and that their extracellular RNA cargo can promote the secretion of proinflammatory cytokines, such as IL-6 and TNF-α, in the brain. To gain more insight into the relationship between periodontal disease (PD) and neuroinflammatory diseases, we investigated the effect of Aa EVs in a mouse model of ligature-induced PD. When EVs were administered through intragingival injection or EV-soaked gel, proinflammatory cytokines were strongly induced in the brains of PD mice. The use of TLR (Toll-like receptor)-reporter cell lines and MyD88 knockout mice confirmed that the increased release of cytokines was triggered by Aa EVs via TLR4 and TLR8 signaling pathways and their downstream MyD88 pathway. Furthermore, the injection of EVs through the epidermis and gingiva resulted in the direct retrograde transfer of Aa EVs from axon terminals to the cell bodies of trigeminal ganglion (TG) neurons and the subsequent activation of TG neurons. We also found that the Aa EVs changed the action potential of TG neurons. These findings suggest that EVs derived from periodontopathogens such as Aa might be involved in pathogenic pathways for neuroinflammatory diseases, neuropathic pain, and other systemic inflammatory symptoms as a comorbidity of periodontitis.

Association of rs142548867 (EEFSEC) and periodontitis Grade C in a young Brazilian population

BACKGROUND

Periodontitis Stage III-IV, Grade C (PerioC) is a severe form of Periodontitis. The individual genetic background has been shown to be an important etiopathogenic factor for the development of this disease in young, systemically healthy, and non-smokers patients. Recently, after exome sequencing of families with a history of the disease, PerioC was associated with three single nucleotide variations (SNVs) - rs142548867 (EEFSEC), rs574301770 (ZNF136), and rs72821893 (KRT25) - which were classified as deleterious or possibly harmful by prediction algorithms.

OBJECTIVE

Seeking to validate these findings in a cohort evaluation, this study aims to characterize the allele and genotypic frequency of the SNVs rs142548867, rs574301770, and rs72821893 in the Brazilian population with PerioC and who were periodontally healthy (PH).

METHODOLOGY

Thus, epithelial oral cells from 200 PerioC and 196 PH patients were harvested at three distinct centers at the Brazilian Southern region, their DNA were extracted, and the SNVs rs142548867, rs574301770, rs72821893 were genotyped using 5'-nuclease allelic discrimination assay. Differences in allele and genotype frequencies were analyzed using Fisher's Exact Test. Only the SNV rs142548867 (C > T) was associated with PerioC.

RESULTS

The CT genotype was detected more frequently in patients with PerioC when compared with PH subjects (6% and 0.5% respectively), being significantly associated with PerioC (odds ratio 11.76, p=0.02).

CONCLUSION

rs142548867 represents a potential risk for the occurrence of this disease in the Brazilian population.

Functionalized Prussian Blue Nanozyme as Dual-Responsive Drug Therapeutic Nanoplatform Against Maxillofacial Infection via Macrophage Polarization

Purpose

Maxillofacial infection is a common disease in stomatology and is difficult to treat owing to its high potential to spread to vital anatomical structures. Excessive levels of reactive oxygen species (ROS) in infected tissues lead to cellular damage and impede tissue regeneration. However, uncontrollable strategies to remove ROS have limited therapeutic efficacy. Nanoparticle systems for scavenging ROS and remodeling the inflammatory microenvironment offer much promise in the treatment of maxillofacial inflammation.

Methods

Here, a novel microenvironment-stimuli-responsive drug delivery nanoplatform (HMPB@Cur@PDA) based on a polydopamine (PDA)-functionalized hollow mesoporous Prussian blue (HMPB) nanozyme was developed for the delivery of curcumin (Cur) in the treatment of maxillofacial infection. Low pH and excess ROS in the inflammatory microenvironment cause degradation of the outer PDA layer of the nanocomplex, exposing the HMPB nanozyme and loaded Cur, which synergistically act as a ROS scavenger and anti-inflammatory agent, respectively, and induce macrophage polarization from the pro-inflammatory M1 to the anti-inflammatory M2 phenotype.

Results

Experiments in vitro provided strong evidence for the application of novel nanocomplexes in scavenging multiple ROS and inhibiting lipopolysaccharide-induced inflammation. In addition, in vivo results obtained using a mouse maxillofacial infection model demonstrated that HMPB@Cur@PDA had excellent biocompatibility, significantly attenuated the inflammatory response in periodontal tissue, and improved the repair of damaged tissue.

Conclusion

Our results indicate that HMPB@Cur@PDA nanocomposites have great potential for ROS regulation as well as having anti-inflammatory effects, providing new insights for the development of dual-response maxillofacial infection treatments.

Immunomodulation in the Treatment of Periodontitis: Progress and Perspectives

Periodontitis is one of the most common dental diseases. Compared with healthy periodontal tissues, the immune microenvironment plays the key role in periodontitis by allowing the invasion of pathogens. It is possible that modulating the immune microenvironment can supplement traditional treatments and may even promote periodontal regeneration by using stem cells, bacteria, etc. New anti-inflammatory therapies can enhance the generation of a viable local immune microenvironment and promote cell homing and tissue formation, thereby achieving higher levels of immune regulation and tissue repair. We screened recent studies to summarize the advances of the immunomodulatory treatments for periodontitis in the aspects of drug therapy, microbial therapy, stem cell therapy, gene therapy and other therapies. In addition, we included the changes of immune cells and cytokines in the immune microenvironment of periodontitis in the section of drug therapy so as to make it clearer how the treatments took effects accordingly. In the future, more research needs to be done to improve immunotherapy methods and understand the risks and long-term efficacy of these methods in periodontitis.

IL10 promoter rs6667202 polymorphism is functional in health but not in grade c periodontitis patients: A pilot study

BACKGROUND AND OBJECTIVE

Previous studies have demonstrated an association between the IL10 promoter rs6667202 (C > A) single-nucleotide polymorphism (SNP) and grade C, stage 3 or 4 periodontitis (Perio4C) in the Brazilian population, where the altered A allele was detected more frequently in these patients. However, no functional analysis of this variation has yet been performed. Thus, the objective of this preliminary study was to evaluate the functionality of rs6667202 in gingival fibroblasts (GFs) of individuals with Perio4C and with periodontal health (PH) stimulated with Aggregatibacter actinomycetencomitans protein extract (AaPE).

METHODS

Patients with PH and Perio4C were segregated according to their genotype (AA, AC, or CC), and a biopsy was performed to establish the culture of the GFs. After GFs exposure to AaPE at 5 µg/ml for 1.5 h, RNA was extracted to analyze IL10 expression by qPCR. Aliquots of the cell's supernatant were subjected to immunoenzymatic analysis (MAGpix) to detect interleukin-10 (IL-10).

RESULTS

In PH, the genotypes AA and AC are related to less expression of IL10 (p = 0.027 and p < 0.0001) and less production of IL-10 (p = 0.002 and p = 0.001), when compared to CC. In Perio4C, there was no statistical difference between the genotypes (p > 0.05), although a lower IL-10 expression and release compared with PH CC was seen (p = 0.033 and p < 0.001).

CONCLUSION

The rs6667202 SNP is functional in PH, as it decreases the expression and production of IL-10. In Perio4C, other factors may be masking its action by altering the IL-10's response.

Oral cancer in non-smoker non-drinker patients. Could comparative pet oncology help to understand risk factors and pathogenesis?

During the last decades there has been a progressive increase in proportion of incidence of oral cancer not related to a known etiologic factor, such as the so-called "oral cancer in young", a relevant tumor in non-smoker non-drinker (NSND) patients. The topic is matter of long standing debate, and adequate study models to analyze this entity are lacking. Spontaneous oral cancer in companion animals such as dogs and cats, presents more clinical and biological similarities with the human oral cancer than any other animal model. In our review we analyze how the study of spontaneous oral cancer in common pets can prospectively prove to be of double usefulness in unraveling the question about the origin of oral cancer in NSND patients, allowing both the analysis of environmental and behavioral risk factors, and the study of how carcinogenic viruses, chronic inflammation, and changes in immunity can influence pre-tumoral and tumoral microenvironment.

The Influence of Diet on Oxidative Stress and Inflammation Induced by Bacterial Biofilms in the Human Oral Cavity

The article is a concise compendium of knowledge on the etiology of pathogenic microorganisms of all complexes causing oral diseases. The influence of particular components of the diet and the role of oxidative stress in periodontal diseases were described. The study investigated the bacteriostatic effect of the diet of adults in in vivo and in vitro tests on the formation of bacterial biofilms living in the subgingival plaque, causing diseases called periodontitis. If left untreated, periodontitis can damage the gums and alveolar bones. Anaerobic bacteria, called periopathogens or periodontopathogens, play a key role in the etiopathogenesis of periodontitis. The most important periopathogens of the oral microbiota are bacteria of all complexes, including the red complex. The obtained results suggest the possibility of using a specific diet in the prevention and treatment of periodontal diseases-already treated as a disease of civilization. The quoted article is an innovative compilation of knowledge on this subject and it can be a valuable source of knowledge for professional hygienists, dentists, peridontologists, dentistry students and anyone who cares about proper oral hygiene. The obtained results suggest the possibility of using this type of diet in the prophylaxis of the oral cavity in order to avoid periodontitis.

Treatment of localized aggressive periodontitis alters local host immunoinflammatory profiles: A long-term evaluation

AIM

To evaluate the local immunoinflammatory profiles in localized aggressive periodontitis patients (LAP) before and after periodontal treatment and maintenance.

METHODS

Sixty-six African-Americans with LAP (7-21 years old) were included. After periodontal examination, all patients received periodontal treatment with mechanical debridement plus systemic amoxicillin/metronidazole for 7 days. Gingival crevicular fluid was collected from diseased and healthy sites at baseline and 3, 6, 12, and 24 months following treatment. Levels of 16 inflammatory/bone resorption markers were determined using Milliplex^® . Univariate and correlation analyses were performed among all parameters/biomarkers. Discriminant analyses (DA) evaluated profile differences between LAP diseased and healthy sites at each time point as compared to the baseline.

RESULTS

Reductions in the clinical parameters (except for visible plaque) were observed at all time points compared to the baseline. Levels of IL-12p70, IL-2, IL-6, MIP-1α, RANKL, and OPG were reduced after treatment, and several cytokines/chemokines were correlated with clinical parameters reductions. DA showed that differences in the immunoinflammatory profiles between LAP diseased and healthy sites decreased after periodontal treatment compared to the baseline.

CONCLUSIONS

Periodontal treatment modified the local immunoinflammatory profile of LAP sites in the long term, as suggested by changes in biomarkers from baseline, along with clinical stability of the disease. (Clinicaltrials.gov number, NCT01330719).

A case of acute necrotizing periodontitis with not known origin

In cases of aggressive periodontal bone destruction, subgingival microbial analysis should be done, tooth extractions should be planned to control disease progression if non‐surgical periodontal treatment is ineffective.

Low-intensity Pulsed Ultrasound regulates alveolar bone homeostasis in experimental Periodontitis by diminishing Oxidative Stress

Periodontitis is a widespread oral disease that results in the loss of alveolar bone. Low-intensity pulsed ultrasound (LIPUS), which is a new therapeutic option, promotes alveolar bone regeneration in periodontal bone injury models. This study investigated the protective effect of LIPUS on oxidative stress in periodontitis and the mechanism underlying this process.

Methods: An experimental periodontitis model was induced by administering a ligature. Immunohistochemistry was performed to detect the expression levels of oxidative stress, osteogenic, and osteoclastogenic markers in vivo. Cell viability and osteogenic differentiation were analyzed using the Cell Counting Kit-8, alkaline phosphatase, and Alizarin Red staining assays. A reactive oxygen species assay kit, lipid peroxidation MDA assay kit, and western blotting were used to determine oxidative stress status in vitro. To verify the role of nuclear factor erythroid 2-related factor 2 (Nrf2), an oxidative regulator, during LIPUS treatment, the siRNA technique and Nrf2^-/- mice were used. The PI3K/Akt inhibitor LY294002 was utilized to identify the effects of the PI3K-Akt/Nrf2 signaling pathway.

Results: Alveolar bone resorption, which was experimentally induced by periodontitis in vivo, was alleviated by LIPUS via activation of Nrf2. Oxidative stress, induced via H₂O₂ treatment in vitro, inhibited cell viability and suppressed osteogenic differentiation. These effects were also alleviated by LIPUS treatment via Nrf2 activation. Nrf2 silencing blocked the antioxidant effect of LIPUS by diminishing heme oxygenase-1 expression. Nrf2^-/- mice were susceptible to ligature-induced periodontitis, and the protective effect of LIPUS on alveolar bone dysfunction was weaker in these mice. Activation of Nrf2 by LIPUS was accompanied by activation of the PI3K/Akt pathway. The oxidative defense function of LIPUS was inhibited by exposure to LY294002 in vitro.

Conclusions: These results demonstrated that LIPUS regulates alveolar bone homeostasis in periodontitis by attenuating oxidative stress via the regulation of PI3K-Akt/Nrf2 signaling. Thus, Nrf2 plays a pivotal role in the protective effect exerted by LIPUS against ligature-induced experimental periodontitis.

Periodontal disease as a possible cause for Alzheimer's disease

Approximately 47 million people worldwide have been diagnosed with dementia, 60%-80% of whom have dementia of the Alzheimer's disease type. Unfortunately, there is no cure in sight. Defining modifiable risk factors for Alzheimer's disease may have a significant impact on its prevalence. An increasing body of evidence suggests that chronic inflammation and microbial dysbiosis are risk factors for Alzheimer's disease. Periodontal disease is a chronic inflammatory disease that develops in response to response to microbial dysbiosis. Many studies have shown an association between periodontal disease and Alzheimer's disease. The intent of this paper was to review the existing literature and determine, using the Bradford Hill criteria, whether periodontal disease is causally related to Alzheimer's disease.

Alveolar bone level at deciduous molars in Flemish children: A retrospective, radiographic study

AIM

The aim of this retrospective radiographic study in Flemish children was to examine the bone level and bone loss around deciduous molars and factors influencing this.

MATERIALS AND METHODS

Two thousand eight hundred ninety six digital intra-oral radiographs of children younger than 18 years old were screened for eligibility. The distance from the cementoenamel junction to the alveolar bone crest was measured, and tooth surfaces were screened for local risk factors that are presumably related to changes in the bone level. A distance >2 mm was defined as bone loss based on previous literature. All measurements were performed by two examiners.

RESULTS

One thousand four hundred ninety one radiographs of 796 patients (mean age 6.46 ± 2.38 years) were included. The distance between the cementoenamel junction and the alveolar bone crest ranged from 0.07 to 2.88 mm, and the mean distance was 0.93 ± 0.37 mm. This distance was positively correlated with age (p < .001). In 3.5% of patients, bone loss was diagnosed. Caries, fillings and pulp pathology were associated with bone loss and higher cementoenamel junction-alveolar bone crest distances (p < .05).

CONCLUSION

This study found a low prevalence of alveolar bone loss in the primary dentition. Both the bone level and bone loss were strongly correlated with local factors.

Prevalence of periodontitis in high school children in Saudi Arabia: a national study

BACKGROUND

The occurrence of periodontitis is rather infrequent in children and adolescence and increases with age. We conducted this study because there have been few epidemiological studies on prevalence of periodontitis in children in Saudi Arabia.

OBJECTIVE

Determine the prevalence of periodontitis in high school children in Saudi Arabia.

DESIGN

Cross-sectional, using cluster and multistage sampling.

SETTING

High school children in Saudi Arabia.

PARTICIPANTS AND METHODS

Periodontal examinations were conducted on a randomized sample of high school children between the ages 15 to 19 in Saudi Arabia. The study spanned from September 2012 to January 2016. Clinical examinations included measurements of the probing depth (PD) percentage of PD ≥4 mm per patient.

MAIN OUTCOME MEASURES

The prevalence of periodontitis (PD ≥4 mm and CAL ≥1 mm), the mean percentage PD ≥4 mm, the mean percentage CAL ≥1 mm, plaque index (PI) and gingival index (GI).

SAMPLE SIZE

2435 high school students.

RESULTS

Of 2435 high school children in the sample, 209 students (8.6%) had periodontitis. The mean (standard deviation) for the PD was 0.59 (0.17) mm. Differences in percentage PD ≥4 mm and CAL ≥1 mm were greater in students with periodontitis ( P<.001). The prevalence of periodontitis was higher among non-Saudis, students who did not brush their teeth and did not visit their dentist regularly. In the bivariate analysis, periodontitis was positively associated with GI, PI, number of teeth extracted, mean percentage PD ≥4 mm, and mean PD. However, in the multivariate analysis, tooth brushing was the main factor protective against periodontitis (odds ratio: 0.62, 95% CI 0.42-0.92, P=.017).

CONCLUSION

Periodontitis prevalence was high compared with Western countries in a nationally representative sample of high school students in Saudi Arabia.

LIMITATIONS

Partial mouth study design, which may underestimate the disease prevalence.

CONFLICT OF INTEREST

None.

Repeated application of photodynamic and antibiotic therapy as an adjunct to root surface debridement in patients with grade C and stage III or IV aggressive periodontitis

PURPOSE

To evaluate the efficacy of antimicrobial photodynamic therapy (aPDT) and antimicrobial therapy on clinical and immunological outcomes of periodontal treatment in patients with periodontitis grade C and stage III or IV.

MATERIAL AND METHOD

The patients recruited in the current research fulfil the clinical case definition of periodontitis 'grade C' in terms of onset of the infection and stage III or IV that defines degree and severity of the disease. One-stage full-mouth ultrasonic debridement (UD) was performed and randomly divided in two groups: Group-I - four applications of aPDT, and Group-II - combination of metronidazole (MTZ) and amoxicillin (AMX) 3 tablets each for 7 days. Whole-mouth periodontal parameters were recorded at baseline, 3-, 6-months after completion of treatment. Gingival crevicular fluid samples were obtained for assessment of inflammatory interleukin (IL)-10 and IL-17 at the same time points.

RESULTS

Seventeen healthy patients completed the study protocol and revealed similar clinical findings at baseline. Bleeding scores significantly reduced in group-I at 3 months post treatment (p < 0.05). It could be seen that group-I showed statistically significant reduction of deep periodontal pockets and gain in CAL in patients with GAP at 3 months (p < 0.05). This difference was maintained at 6 months of follow-up (p < 0.001). Group-II was capable of increasing the levels of IL-10 and reducing IL-17 in GCF at both time periods compared to Group-I (p < 0.05). Group-I did not have significant effect on either cytokine levels in GCF (p > 0.05).

CONCLUSION

Antimicrobial photodynamic therapy improved severe deep periodontal pockets. However, the combination of antimicrobial therapy helped in reducing proinflammation in grade C and stage III or IV periodontitis.

Cranberry Proanthocyanidins Neutralize the Effects of Aggregatibacter actinomycetemcomitans Leukotoxin

Aggregatibacter actinomycetemcomitans is a Gram-negative bacterium that has been strongly associated with localized aggressive periodontitis. The capacity of A. actinomycetemcomitans to produce a leukotoxin (LtxA) that activates pyroptosis in macrophages and induces the release of endogenous danger signals is thought to play a key role in the disease process. The aim of the present study was to investigate the effects of cranberry proanthocyanidins (PACs) on gene expression and cytotoxic activities of LtxA. We showed that cranberry PACs dose-dependently attenuate the expression of genes making up the leukotoxin operon, including ltxB and ltxC, in the two strains of A. actinomycetemcomitans tested. Cranberry PACs (≥62.5 µg/mL) protected macrophages against the cytotoxic effect of purified LtxA. Moreover, cranberry PACs reduced caspase-1 activation in LtxA-treated macrophages and consequently decreased the release of both IL-1β and IL-18, which are known as damage-associated molecular patterns (DAMPs) and contribute to the progression of periodontitis by increasing cell migration and osteoclastogenesis. In addition, cranberry PACs reduced the expression of genes encoding the P2X7 receptor and NALP3 (NACHT, LRR and PYD domains-containing protein 3), which play key roles in pore formation and cell death. Lastly, cranberry PACs blocked the binding of LtxA to macrophages and consequently reduced the LtxA-mediated cytotoxicity. In summary, the present study showed that cranberry PACs reduced LtxA gene expression in A. actinomycetemcomitans and neutralized the cytolytic and pro-inflammatory responses of human macrophages treated with LtxA. Given these properties, cranberry PACs may represent promising molecules for prevention and treatment of the aggressive form of periodontitis caused by A. actinomycetemcomitans.

microRNA-132 inhibits osteogenic differentiation of periodontal ligament stem cells via GDF5 and the NF-κB signaling pathway

BACKGROUND

Periodontal ligament stem cells (PDLSCs) could differentiate into osteoblasts and have a great prospect in treating bone diseases. microRNAs (miRs) and nuclear factor kappa-B (NF-κB) signaling pathway have proved pivotal in regulating osteogenic differentiation. This study intended to discuss the mechanism of miR-132 and NF-κB in PDLSC osteogenesis.

METHODS

PDLSCs were firstly cultured, induced, and identified by detecting the surface markers and observing cell morphology. Levels of osteogenic markers alkaline phosphatase (ALP), bone morphogenetic proteins 2 (BMP2), runt-related transcription factor 2 (Runx2) and osteocalcin (OCN), along with miR-132 expression were measured. The osteoblast activity and mineral deposition were detected by ALP and alizarin red S (ARS) stainings. The targeting relationship between miR-132 and growth differentiation factor 5 (GDF5) was verified. The gain-and loss-of-function was performed to discuss roles of miR-132 and GDF5 in osteogenic differentiation of PDLSCs. Besides, levels of NF-κB signaling pathway-related proteins were measured.

RESULTS

In osteogenic differentiation of PDLSCs, levels of ALP, BMP2, Runx2 and OCN were upregulated while miR-132 was downregulated. Overexpressing miR-132 reduced levels of osteogenic markers, osteoblast activity, ALP and ARS intensity and the activation of NF-κB axis. GDF5 is a target of miR-132 and GDF5 overexpression reversed the inhibitory effects of overexpressed miR-132 on PDLSC osteogenesis.

CONCLUSION

Together, miR-132 could inhibit PDLSC osteogenesis via targeting GDF5 and activating NF-κB axis. These data provide useful information for PDLSC application in periodontal therapy.

Differential Expression of Inflammation-Related Genes in Down Syndrome Patients with or without Periodontal Disease

Aim

Aware that Down Syndrome patients present among their clinical characteristics impaired immunity, the aim of this study is to identify the statistically significant differences in inflammation-related gene expression by comparing Down Syndrome patients with Periodontal Disease (DS+PD+) with Down Syndrome patients without Periodontal Disease (DS+PD-), and their relationship with periodontitis as a chronic oral inflammatory clinical feature.

Materials and Methods

Case study and controls on eleven Down Syndrome patients (DS+PD+ vs. DS+PD-). RNA was extracted from peripheral blood using a Qiagen PAXgene Blood miRNA Kit when performing an oral examination. A search for candidate genes (92 selected) was undertaken on the total genes obtained using a Scientific GeneChip® Scanner 3000 (Thermo Fisher Scientific) and Clariom S solutions for human, mouse, and rat chips, with more than 20,000 genes annotated for measuring expression levels.

Results

Of the 92 inflammation-related genes taken initially, four genes showed a differential expression across both groups with a p value of <0.05 from the data obtained using RNA processing of the patient sample. Said genes were TNFSF13B (p = 0.0448), ITGB2 (p = 0.0033), ANXA3 (p = 0.0479), and ANXA5 (p = 0.016).

Conclusions

There are differences in inflammation-related gene expression in Down Syndrome patients when comparing patients who present a state of chronic oral inflammation with patients with negative rates of periodontal disease.

The subgingival microbial community of feline periodontitis and gingivostomatitis: characterization and comparison between diseased and healthy cats

Periodontitis is a common and important health problem in domestic cats. The subgingival microbiota of cats diagnosed with chronic periodontitis (CP), aggressive periodontitis (AP), and feline chronic gingivostomatitis (FCGS) are not well characterized. Thus, the aim of the present study was to characterize and compare the periodontal microbiota of periodontally healthy cats versus cats diagnosed with CP, AP, and FCGS by using next-generation sequencing. In total, 44 domestic cats were enrolled, and 139 subgingival samples were subjected to 16S rRNA gene sequencing to investigate the microbiota composition of each periodontal group evaluated. Our results identified several key genera previously described in periodontal disease (e.g. Treponema and Filifactor) and in the oral microbiota (e.g. Moraxella and Capnocytophaga) of healthy cats. Phylogenetic beta diversity analysis showed that the microbiota of periodontally healthy cats were distinguishable from diseased cats. Even though most of the genera known to be associated with periodontal disease were also identified in healthy cats, they were present at significantly lower relative abundance. Remarkably, alpha diversity was found to be higher in the disease groups compared to healthy animals. These results suggest a pathological mechanism involving opportunistic behavior. Our findings corroborate those in the current literature regarding the complexity of the subgingival microbiota of the domestic cat and reveal both differences and similarities among periodontally healthy and diseased cats.

Porphyromonas gingivalis in saliva associates with chronic and aggressive periodontitis

Objective: To characterize the salivary microbiota of patients with aggressive periodontitis, patients with chronica periodontitis and orally healthy individuals.

Methods: A total of 81 unstimulated saliva samples from aggressive periodontitis patients (n = 31), chronic periodontitis patients (n = 25), and orally healthy controls (n = 25) were examined. The V1-V3 region of the 16S rDNA gene was sequenced with Illumina® MiSeq^TM, and sequences were annotated to the expanded Human Oral Microbiome Database (eHOMD).

Results: A mean percentage of 97.6 (range: 89.8–99.7) of sequences could be identified at species level. Seven bacterial species, including Porphyromonas gingivalis, were identified with significantly higher relative abundance in saliva from aggressive periodontitis patients than in saliva from orally healthy controls. Salivary abundance of P. gingivalis could discriminate aggressive (AUC: 0.80, p = 0.0001) and chronic periodontitis (AUC: 0.72, p = 0.006) from healthy controls. Likewise, salivary presence of P. gingivalis was significantly associated with aggressive (p < 0.0001, RR: 8.1 (95% CI 2.1–31.2)) and chronic periodontitis (p = 0.002, RR: 6.5 (95% CI: 1.6–25.9)).

Conclusion: Salivary presence and relative abundance of P. gingivalis associate with aggressive and chronic periodontitis, but do not discriminate between aggressive and chronic periodontitis.

Novel rare frameshift variation in aggressive periodontitis: Exomic and familial-screening analysis

BACKGROUND

Aggressive periodontitis (AgP), currently periodontitis grade C, presents early onset, rapid progression, and a poorly established genetic association. Thus, this study aimed to identify genetic variants associated with AgP via whole exome sequencing (WES) through a familial screening approach.

METHODS

WES was performed in two nuclear families, including a proband and a parent affected by AgP and an unaffected parent and sibling. Common variants among affected individuals, excluding those common to healthy people, from each family, composed the data set associated with AgP. In silico analysis evaluated the impact of each variant on protein structure and protein-protein interactions. Moreover, identified deleterious variants were validated in a populational analysis (n = 96).

RESULTS

The missense single nucleotide variations (SNVs) rs142548867 in EEFSEC (c.668C>T), rs574301770 in ZNF136 (c.466C>G), and rs72821893 in KRT25 (c.800G>A) and the frameshift indels rs37146475 in GPRC6A (c.2323-2324insT) and c.1366_1372insGGAGCAG in ELN were identified in AgP and have a predicted functional impact on proteins. In silico analysis indicated that the indel in GPRC6A generates a loss of the C-terminal tail of the Gprca protein. Furthermore, this SNV was significantly associated with AgP in a population-based investigation.

CONCLUSION

Novel frameshift variation in GPRC6A (c.2323-2324insT) was identified as a potential genetic alteration associated with AgP occurrence.

Risk indicators of aggressive periodontitis in a Jordanian population

BACKGROUND

Knowledge of the risk indicators of aggressive periodontitis (AgP) will help clinicians to better diagnose the disease, put a treatment plan that involves modification of modifiable risk indicators, understand non-modifiable risk indicators, and may potentially serve as an aid in developing preventive programs. The objective of the present study was to assess risk indicators of aggressive periodontitis (AgP) in Jordan including socio-demographic factors, oral hygiene habits, smoking, family history and parents' consanguinity.

METHODS

A total of 162 patients (81 AgP and 81 controls), attending the Periodontology clinic at Jordan University of Science and Technology, Dental Teaching Centre, were interviewed and examined. All AgP subjects had full periodontal and radiographic examination. The data recorded included socio-demographic and economic variables, oral hygiene and smoking habits, family history and parents' consanguinity.

RESULTS

Most AgP patients were young females, had ≤12 years of education, lived in urban areas and brushed their teeth ≥ once daily. Risk indicators of AgP included: age > 35 years, female gender and positive family history.

CONCLUSIONS

Risk indicators associated with AgP in this study population were: age > 35 years, female gender and positive family history of periodontal disease.

Macrophage immunomodulation in chronic osteolytic diseases-the case of periodontitis

Periodontitis (PD) is a chronic osteolytic disease that shares pathogenic inflammatory features with other conditions associated with nonresolving inflammation. A hallmark of PD is inflammation-mediated alveolar bone loss. Myeloid cells, in particular polymorphonuclear neutrophils (PMN) and macrophages (Mac), are essential players in PD by control of gingival biofilm pathogenicity, activation of adaptive immunity, as well as nonresolving inflammation and collateral tissue damage. Despite mounting evidence of significant innate immune implications to PD progression and healing after therapy, myeloid cell markers and targets for immune modulation have not been validated for clinical use. The remarkable plasticity of monocytes/Mac in response to local activation factors enables these cells to play central roles in inflammation and restoration of tissue homeostasis and provides opportunities for biomarker and therapeutic target discovery for management of chronic inflammatory conditions, including osteolytic diseases such as PD and arthritis. Along a wide spectrum of activation states ranging from proinflammatory to pro-resolving, Macs respond to environmental changes in a site-specific manner in virtually all tissues. This review summarizes the existing evidence on Mac immunomodulation therapies for osteolytic diseases in the broader context of conditions associated with nonresolving inflammation, and discusses osteoimmune implications of Macs in PD.

Polydopamine Nanoparticles as Efficient Scavengers for Reactive Oxygen Species in Periodontal Disease

Antioxidative therapy has been considered an efficient strategy for the treatment of a series of excessive reactive oxygen species (ROS)-triggered diseases, including oxidative-stress-induced periodontal disease. However, current natural enzymes and nanozymes often show their high specificity toward given ROS and have insufficient antioxidative effects against multiple ROS generated in the diseases process. Meanwhile, multienzyme-based antioxidant defense systems are usually confined by the complicated synthesis as well as potential unwanted residue and toxicity. Various supports are highly needed to immobilize natural enzymes and antioxidants during the biorelated usages due to their low operational stability and difficulty of reuse. To overcome these limitations, we develop a high-performance platform by using biodegradable polydopamine nanoparticles (PDA NPs) as smart ROS scavengers in oxidative stress-induced periodontal disease. Although PDA-based materials are well-known to eliminate ROS both in vitro and in vivo, their antioxidative performance in periodontal disease and relative mechanisms have yet to be well-explored. In this study, PDA NPs can act as ROS scavengers in dental specialties with ideal outcomes. Spectroscopic and in vitro experiments provide strong evidence for the roles of PDA NPs in scavenging multiple ROS and suppressing ROS-induced inflammation reactions. In addition to the above investigations, the results from a murine periodontitis model clearly demonstrate the feasibility of PDA NPs as robust antioxidants with which to remove ROS and decrease periodontal inflammation without any side effects. Taken together, the results from our present study will provide valuable insight into the development of safe and efficient antioxidant defense platforms for further biomedical uses.

Effect of total sonicated Aggregatibacter actinomycetemcomitans fragments on gingival stem/progenitor cells

Background

Aggregatibacter-actinomycetemcomitans (A.actinomycetemcomitans) are strongly associated with localized-aggressive-periodontitis (LAgP). The study’s aim was to test for the first time the effect of total sonicated A.actinomycetemcomitans-bacterial-fragments on gingival mesenchymal stem/progenitor cells’ (G-MSCs) proliferation and regenerative gene expression in-vitro.

Material and Methods

G-MSCs were isolated, characterized, expanded and stimulated by total sonicated A.actinomycetemcomitans-bacterial-fragments (0 (negative-control), 15, 60, 120 and 240µg/ml; serovar-b; n=6/group). Cellular proliferation and NF-κβ (NFKB1), Alkaline Phosphatase (ALPL), Collagen-I (COL1A1), Collagen-III (COL3A1), Osteonectin (SPARC) and Osteopontin (SPP1) m-RNA expression were assessed via reverse-transcription-polymerase-chain-reaction (RT-PCR) at 24, 48 and 72 hours and CFUs-ability evaluated at twelve days.

Results

G-MSCs demonstrated stem/progenitor cells’ characteristics. A.actinomycetemcomitans-bacterial-fragments (up to 72 hours) resulted in marked G-MSCs’ proliferation over-time (p<0.001) and elevated NFKB1 (p=0.017), COL1A1 (p=0.025), SPARC (p=0.025), decreased ALPL (p=0.017), with no significant differences for COL3A1 and SPP1 expression or stimulation times (p>0.05; Friedman-test). Longer-term stimulation for twelve days reduced G-MSCs’ CFUs.

Conclusions

Sonicated A.actinomycetemcomitans-bacterial-fragments’ exert beneficial short-term effects on G-MSCs’ proliferative and non-mineralized tissue forming aptitude. Results shed new light on the importance of periodontal treatment for LAgP patients, using power driven sonic/ultrasonic devices, which, in addition to reducing the subgingival microbial load, produces cell-stimulatory A.actinomycetemcomitans-bacterial-fragments, with positive attributes on tissue reparative/regenerative responses of tissue resident stem/progenitor cells in their niche.

Key words:Ultrasonic, Aggregatibacter actinomycetemcomitans, stem cells, gingiva, Aggressive periodontitis.

Clinical performance of non-surgical periodontal therapy in a large Chinese population with generalized aggressive periodontitis

AIM

This study aimed to evaluate clinical performance of non-surgical periodontal treatment (NSPT) and its influential factors in a large Chinese population with generalized aggressive periodontitis (GAgP).

MATERIAL AND METHODS

Longitudinal periodontal examination data of 1,004 GAgP patients (numbers of patients with observation periods 6 weeks~, 3 months~, 6 months~, 1 year~, 3 years~ and >5 years were 203, 310, 193, 205, 70 and 23, respectively) were extracted from a hospital-based electronic periodontal charting record system and analysed by multilevel analysis.

RESULTS

Mean probing depth (PD) and attachment loss (AL) reductions at patient level were 1.17 mm and 1.07 mm, respectively. Multilevel analysis demonstrated PD reductions after maintenance were mainly influenced by frequency of supportive periodontal treatment (FSPT), gender, adjunctive systemic use of antibiotics, baseline mobility, tooth type and baseline PD and bleeding index reductions were mainly influenced by FSPT, adjunctive systemic use of antibiotics, baseline AL, baseline mobility, tooth type and baseline PD.

CONCLUSION

The clinical performance of NSPT on patients with GAgP was proved in the large Chinese population. Outcomes of NSPT were mainly influenced by FSPT, adjunctive systemic use of antibiotics, baseline mobility, tooth type and baseline PD.

Oral and Blood Neutrophil Activation States during Experimental Gingivitis

Polymorphonuclear neutrophils (PMNs) are the primary leukocytes present in the healthy and inflamed oral cavity. While unique PMN activation states have been shown to differentiate health and periodontitis, little is known about the changes in PMN activation states that occur during the transition from periodontal health to gingivitis. The objective of this study was to characterize oral and circulatory PMNs during induction and resolution of experimental gingivitis. Healthy volunteers were recruited to undergo experimental gingivitis. Clinical assessment of pocket depths, bleeding on probing, gingival index, and plaque index, as well as flow cytometric analysis of CD (cluster of differentiation) activation markers on blood and oral PMNs, was performed weekly. All clinical parameters increased significantly during the induction period and returned to baseline levels during the resolution phase. During the induction phase, while oral PMN counts increased, oral PMN activation state based on surface expression of CD63, CD11b, CD16, and CD14 was diminished compared to those seen in health and during the resolution phase. PMNs in circulation during onset showed increased activation based on CD55, CD63, CD11b, and CD66a. Using clinical parameters and oral PMN counts assessed at day 21, we noted 2 unique disease patterns where one-third of subjects displayed an exaggerated influx of oral PMNs with severe inflammation compared to the majority of the population who experienced a moderate level of inflammation and PMN influx. This supports the notion that PMN influx and severe inflammatory changes during gingivitis could identify subjects at risk for the development of severe gingival inflammation and progression toward destructive periodontitis. This study demonstrates that oral PMN activation states are reduced in gingivitis and suggest that only in periodontitis do PMNs become hyperactivated and tissue damaging.

Knowledge Transfer Statement: Our article creates a paradigm for future studies of the evolution of essential oral and circulatory biomarkers to identify individuals at risk to develop periodontitis at an early stage of periodontal disease, which is reversible upon proper oral hygiene practices and dental treatments.

Molecular-level evaluation of selected periodontal pathogens from subgingival regions in canines and humans with periodontal disease

Dogs commonly serve as a model for various human conditions, including periodontal diseases. The aim of this study was to identify the anaerobic bacteria that colonize the subgingival areas in dogs and humans by using rapid real-time polymerase chain reaction (RT-PCR)-based tests and to compare the results obtained in each species. Bacterial microflora evaluations, both quantitative and qualitative, were performed by applying ready-made tests on twelve dogs and twelve humans. Five samples were collected from each subject's deepest gingival pockets and joined to form a collective sample. The results of the study revealed interspecies similarities in the prevalences of Porphyromonas (P.) gingivalis, Treponema denticola, Tannerella forsythia, and Fusobacterium nucleatum. Red complex bacteria comprised the largest portion of the studied bacterial complexes in all study groups, with P. gingivalis being the most commonly isolated bacterium. The results show similarities in the prevalence of bacterial microflora in dogs and humans. Microbiological analysis of gingival pockets by using rapid real-time PCR-based tests in clinical practice, both veterinary and human, can facilitate the choice of appropriate pharmacological treatment and can provide a basis for subsequent verification of the treatment's effectiveness.

Comparison of Cone Beam Computed Tomography-Derived Alveolar Bone Density Between Subjects with and without Aggressive Periodontitis

INTRODUCTION

Understanding the changes in bone density of patients affected by aggressive periodontitis could be useful in early disease detection and proper treatment planning.

AIM

The aim of this study was to compare alveolar bone density in patients affected with aggressive periodontitis and periodontally healthy individuals using Cone Beam Computed Tomography (CBCT).

MATERIALS AND METHODS

This cross-sectional study was conducted on 20 patients with a confirmed diagnosis of aggressive periodontitis. Twenty periodontally healthy patients attending the dental clinics for implant placement or extraction of impacted third molars served as controls. Alveolar bone density was measured using CBCT scanning. Comparisons between aggressive periodontitis group and controls for age and alveolar bone density of the anterior and posterior regions were performed using an independent sample t-test. Multivariable linear regression models were also performed.

RESULTS

The differences between groups in regard to age, anterior and posterior alveolar bone density was not statistically significant (p<0.05). In the posterior region, the multivariable regression model showed that bone density was not associated with age, gender or the study groups. Whereas, in the anterior region, patient's age was found to be significantly associated with bone density, p=0.014.

CONCLUSION

Alveolar bone density as measured by CBCT in aggressive periodontitis patients was not different from periodontally healthy individuals. Further studies are needed to confirm these findings.

The use of platelet-rich fibrin combined with periodontal ligament and jaw bone mesenchymal stem cell sheets for periodontal tissue engineering

Periodontal regeneration involves the restoration of at least three unique tissues: cementum, periodontal ligament tissue (PDL) and alveolar bone tissue. Here, we first isolated human PDL stem cells (PDLSCs) and jaw bone mesenchymal stem cells (JBMSCs). These cells were then induced to form cell sheets using an ascorbic acid-rich approach, and the cell sheet properties, including morphology, thickness and gene expression profile, were compared. Platelet-rich fibrin (PRF) derived from human venous blood was then fabricated into bioabsorbable fibrin scaffolds containing various growth factors. Finally, the in vivo potential of a cell-material construct based on PDLSC sheets, PRF scaffolds and JBMSC sheets to form periodontal tissue was assessed in a nude mouse model. In this model, PDLSC sheet/PRF/JBMSC sheet composites were placed in a simulated periodontal space comprising human treated dentin matrix (TDM) and hydroxyapatite (HA)/tricalcium phosphate (TCP) frameworks. Eight weeks after implantation, the PDLSC sheets tended to develop into PDL-like tissues, while the JBMSC sheets tended to produce predominantly bone-like tissues. In addition, the PDLSC sheet/PRF/JBMSC sheet composites generated periodontal tissue-like structures containing PDL- and bone-like tissues. Further improvements in this cell transplantation design may have the potential to provide an effective approach for future periodontal tissue regeneration.

Regulator of Calcineurin 1 in Periodontal Disease

Nuclear factor of activated T-cells (NFAT) and NF-kB pathway associated processes are involved in the pathogenesis of various inflammatory disorders, for example, periodontal disease. The activation of these pathways is controlled by the regulator of calcineurin 1 (RCAN1). The aim of this study was to elucidate the role of RCAN1 in periodontal disease. Healthy and inflamed periodontal tissues were analyzed by immunohistochemistry and immunofluorescence using specific rabbit polyclonal anti-RCAN1 antibodies. For expression analysis human umbilical vein endothelial cells (HUVEC) were used. HUVEC were incubated for 2 h with Vascular Endothelial Growth Factor (VEGF) or with wild type and laboratory strains of Porphyromonas gingivalis (P. gingivalis). Expression analysis of rcan1 and cox2 was done by real time PCR using specific primers for rcan1.4 and cox2. The expression of rcan1 was found to be significantly suppressed in endothelial cells of chronically inflamed periodontal tissues compared to healthy controls. Rcan1 and cox2 were significantly induced by VEGF and wild type and laboratory P. gingivalis strains. Interestingly, the magnitude of the rcan1 and cox2 induction was strain dependent. The results of this study indicate that RCAN1 is suppressed in endothelial cells of chronically inflamed periodontal tissues. During an acute infection, however, rcan1 seems to be upregulated in endothelial cells, indicating a modulating role in immune homeostasis of periodontal tissues.

Periodontal disease's contribution to Alzheimer's disease progression in Down syndrome

People with Down syndrome (DS) are at an increased risk for Alzheimer's disease (AD). After 60 years of age, >50% of DS subjects acquire dementia. Nevertheless, the age of onset is highly variable possibly because of both genetic and environmental factors. Genetics cannot be modified, but environmental risk factors present a potentially relevant intervention for DS persons at risk for AD. Among them, inflammation, important in AD of DS type, is potential target. Consistent with this hypothesis, chronic peripheral inflammation and infections may contribute to AD pathogenesis in DS. People with DS have an aggressive form of periodontitis characterized by rapid progression, significant bacterial and inflammatory burden, and an onset as early as 6 years of age. This review offers a hypothetical mechanistic link between periodontitis and AD in the DS population. Because periodontitis is a treatable condition, it may be a readily modifiable risk factor for AD.

Aggregatibacter actinomycetemcomitans: virulence of its leukotoxin and association with aggressive periodontitis

Periodontitis is an infection-induced inflammatory disease that causes loss of the tooth supporting tissues. Much focus has been put on comparison of the microbial biofilm in the healthy periodontium with the diseased one. The information arising from such studies is limited due to difficulties to compare the microbial composition in these two completely different ecological niches. A few longitudinal studies have contributed with information that makes it possible to predict which individuals who might have an increased risk of developing aggressive forms of periodontitis, and the predictors are either microbial or/and host-derived factors. The most conspicuous condition that is associated with disease risk is the presence of Aggregatibacter actinomycetemcomitans at the individual level. This Gram-negative bacterium has a great genetic variation with a number of virulence factors. In this review we focus in particular on the leukotoxin that, based on resent knowledge, might be one of the most important virulence factors of A. actinomycetemcomitans.

Association between plasma leptin level and systemic inflammatory markers in patients with aggressive periodontitis

Background:

Increasing evidence supports an association between periodontitis and systemic diseases. Leptin is involved both in the energy metabolism and inflammatory processes and is suggested to be a link between periodontal infection and systemic health. The present study aimed to evaluate the peripheral leptin concentration in patients with aggressive periodontitis (AgP) and to explore the relationship between leptin and systemic inflammation.

Methods:

Ninety patients with AgP visiting the Clinic of the Periodontology Department, Peking University School and Hospital of Stomatology between July 2001 and May 2006, and 44 healthy controls (staff and student volunteers in the same institute) were recruited. Plasma levels of leptin and inflammatory cytokines including interleukin (IL)-1β, IL-6, tumor necrosis factor-α (TNF-α) and C-reactive protein (CRP) were measured by enzyme-linked immunosorbent assay. Correlation and multiple linear regression analysis were performed to analyze the association between plasma leptin level and other variables.

Results:

Plasma leptin level of AgP group was significantly higher than that of the control group (19.7 ± 4.4 ng/ml vs. 7.5 ± 1.3 ng/ml, P < 0.01). After controlling for age, gender, and body mass index, positive correlation was observed between plasma leptin concentration and log-transformed levels of pro-inflammatory cytokines (IL-1β, IL-6, TNF-α and CRP), and the partial correlation coefficients ranged from 0.199 to 0.376 (P < 0.05). Log-transformed IL-1β and IL-6 levels entered the final regression model (standardized β were 0.422 and 0.461 respectively, P < 0.01).

Conclusions:

Elevated plasma leptin concentration may be associated with increased systemic levels of inflammatory markers in AgP patients.

Gene-Expression Profiles in Generalized Aggressive Periodontitis: A Gene Network-Based Microarray Analysis

BACKGROUND

In this study, molecular biomarkers that play a role in the development of generalized aggressive periodontitis (GAgP) are investigated using gingival tissue samples through omics-based whole-genome transcriptomics while using healthy individuals as background controls.

METHODS

Gingival tissue biopsies from 23 patients with GAgP and 25 healthy individuals were analyzed using gene-expression microarrays with network and pathway analyses to identify gene-expression patterns. To substantiate the results of the microarray studies, real-time quantitative reverse transcription-polymerase chain reaction (qRT-PCR) was performed to assess the messenger RNA (mRNA) expression of MZB1 and DSC1. The microarrays and qRT-PCR resulted in similar gene-expression changes, confirming the reliability of the microarray results at the mRNA level.

RESULTS

As a result of the gene-expression microarray studies, four significant gene networks were identified. The most upregulated genes were found as MZB1, TNFRSF17, PNOC, FCRL5, LAX1, BMS1P20, IGLL5, MMP7, SPAG4, and MEI1; the most downregulated genes were found as LOR, LAMB4, AADACL2, MAPT, ARG1, NPR3, AADAC, DSC1, LRRC4, and CHP2.

CONCLUSIONS

Functions of the identified genes that were involved in gene networks were cellular development, cell growth and proliferation, cellular movement, cell-cell signaling and interaction, humoral immune response, protein synthesis, cell death and survival, cell population and organization, organismal injury and abnormalities, molecular transport, and small-molecule biochemistry. The data suggest new networks that have important functions as humoral immune response and organismal injury/abnormalities. Future analyses may facilitate proteomic profiling analyses to identify gene-expression patterns related to clinical outcome.