Principles of periodontology

Hypomethylation of the interleukin-6 promoter in gingival tissue of patients with periodontitis

BACKGROUND

DNA methylation may influence cytokine expression and clinical manifestations of periodontitis. This study assessed the interleukin (IL)-6 DNA methylation in gingivae with and without clinical inflammation and its impact on clinical manifestations and cytokine expression.

METHODS

Sixty-two gingival biopsies (17 from controls and 45 from periodontitis sites) were analyzed. IL-6 protein concentrations were measured using an enzyme-linked immunosorbent assay, and methylation of the IL-6 promoter was analyzed by bisulfite sequencing. At 19 motifs spanning from 1200 to 27 base pairs (bp), the methylation rates for each motif and the overall promoter region were assessed.

RESULTS

IL-6 concentrations were significantly higher in the periodontitis group than in the control group (135.69 ± 10.24 vs. 65.17 ± 29.18 pg/mL) and were positively correlated with probing depth (PD) and clinical attachment loss (CAL) (r = 0.59 and 0.48, respectively). The overall methylation rate was significantly lower in the disease group (43.97% ± 4.54% vs. 39.54% ± 7.66%) and negatively correlated with PD, CAL, and IL-6 concentrations. Similar trends were also observed for the -74-bp motif: The methylation rate was lower in the periodontitis group than in the control group (8.9% vs. 41.2%, with a relative risk of 0.216), and gingivae with methylation at -74-bp exhibited lower PD and CALs but higher overall methylation rates.

CONCLUSION

DNA hypomethylation of the IL-6 promoter region, particularly the -74-bp motif, was linked to increased cytokine expression and periodontal clinical signs, suggesting its role in disease progression.

PLAIN LANGUAGE SUMMARY

This study examined how changes in the interleukin (IL)-6 gene-specifically through a process called DNA methylation-are linked to gum disease (periodontitis) and its symptoms. Sixty-two gum tissue samples were collected: 17 from individuals without gum disease and 45 from those with it. The gum tissues from people with periodontitis showed higher levels of the IL-6 protein, which were associated with more severe gum damage, such as deeper pockets around the teeth and greater loss of attachment. The researchers also found that a part of the IL-6 gene was less methylated in people with gum disease-a change that can lead to increased gene activity. This was especially evident at a specific site in the gene, 74 base pairs from the start. Lower methylation at this site was linked to higher IL-6 levels and more severe symptoms. Overall, the findings suggest that reduced methylation of the IL-6 gene may contribute to the progression of gum disease.

Evaluating efficacy of laser-assisted new attachment procedure and adjunctive low-level laser therapy in treating periodontitis: A single-blind randomized controlled clinical study

PURPOSE

This study aimed to evaluate the effectiveness of the laser-assisted new attachment procedure (LANAP) and low-level laser therapy (LLLT) on clinical, biochemical, and radiographic parameters when applied alongside scaling and root planing (SRP).

METHODS

The study was designed as a randomized controlled, single-blind, parallel trial involving 68 patients diagnosed with periodontitis. The participants were divided into three groups: Group 1: SRP (control), Group 2: LANAP, and Group 3: LLLT. Clinical measurements, gingival crevicular fluid (GCF) samples, and standard periapical radiographs were obtained pre-treatment and at one- and three-month follow-ups. In GCF, interleukin-1beta (IL-1β), interleukin-10 (IL-10), and vascular endothelial growth factor (VEGF) were analyzed.

RESULTS

In moderate (4-6 mm) and deep pockets (≥ 7 mm), laser-treated groups showed a significant reduction in pocket depth (PD) and clinical attachment level (CAL) compared to the control group. However, there were no statistically significant differences in biochemical markers between the groups. Group 2 demonstrated significant bone filling compared to the control group.

CONCLUSION

In deep pockets, laser-treated groups provide additional benefits to SRP. The application of LLLT positively affected recession (REC).

TRIAL REGISTRATION NUMBER

NCT04694222 Date of registration: 01/01/2021.

Microbial dysbiosis in periodontitis and peri-implantitis: pathogenesis, immune responses, and therapeutic

The oral microbiome comprises over 700 distinct species, forming complex biofilms essential for maintaining oral and systemic health. When the microbial homeostasis in the periodontium is disrupted, pathogens within the biofilm can cause periodontitis and peri-implantitis, inducing host immune responses. Understanding the role of microbial communities and the immune mechanisms in oral health and disease is crucial for developing improved preventive, diagnostic and therapeutic strategies. However, many questions remain about how changes in bacterial populations contribute to the development and progression of these conditions. An electronic and manual literature search was conducted using PubMed, Excerpta Medica, Frontiers Reports and the Wiley Online Library databases for relevant articles. Data from these publications were extracted and the overall findings were summarized in a narrative manner. The variations in microbial communities and immune responses of periodontitis and peri-implantitis are explored. Dysbiosis of the subgingival microbiome-characterized by an increase in pathogenic bacteria such as Porphyromonas gingivalis, Tannerella forsythia, and Aggregatibacter actinomycetemcomitans-plays a pivotal role in the initiation and progression of periodontitis. As for peri-implantitis, alterations include a higher abundance of opportunistic pathogens and reduced microbial diversity around implants. Moreover, oral dysbiosis potentially influencing systemic health through immune-mediated pathways. Regional immunity of periodontium involving neutrophils, T helper cells-17, and immune-related cytokines is crucial for maintaining periodontal homeostasis and responding to microbial imbalances. Additionally, the impact of non-mechanical treatments-such as probiotics and laser therapy-on the oral microbiome is discussed, demonstrating their potential in managing microbial dysbiosis. These findings underscore that bacterial dysbiosis is a central factor in the development of periodontitis and peri-implantitis. Maintaining microbial balance is essential for preventing these diseases, and interventions targeting the microbiome could enhance treatment outcomes. Strategies focusing on controlling pathogenic bacteria, modulating immune responses, and promoting tissue regeneration are key to restoring periodontal stability. Further research is needed to clarify the mechanisms underlying the transition from peri-implant mucositis to peri-implantitis and to optimize prevention and treatment approaches, considering the complex interactions between the microbiome and host immunity.

Inhibition of soluble epoxide hydrolase reverses bone loss in periodontitis by upregulating EMCN and inhibiting osteoclasts

BACKGROUND

Improving the microenvironment to augment endogenous regenerative potential has emerged as a fundamental concept for stimulating and expediting periodontal tissue repair and regeneration. Previous studies have demonstrated that TPPU, a soluble epoxide hydrolase inhibitor (sEHi), mediates the suppression of inflammatory bone loss in periodontitis models. However, the underlying mechanisms remain largely elusive.

METHODS

In this study, we constructed a human umbilical vein endothelial cell (HUVEC) and periodontal ligament stem cell (PDLSC) coculture system in vitro and tested the anti-inflammatory effect of TPPU under inflammatory conditions. The roles of HIF-1α and Endomucin (EMCN) in the anti-inflammatory effects of TPPU were analyzed. The effects of TPPU on osteogenesis and osteoclastogenesis in cocultured cells were examined. The in vivo periodontitis model further verified the effects of TPPU on inhibiting neutrophil adhesion and inflammation and inhibiting osteoclasts.

RESULTS

Our in vitro experiments demonstrated that TPPU enhances the interaction between mesenchymal stem cells and vascular endothelial cells to enhance anti-inflammatory and osteogenic differentiation effects and revealed a new anti-inflammatory mechanism of TPPU involving the upregulation of EMCN in endothelial cells to prevent lymphocyte recruitment. We also confirmed that TPPU inhibits osteoclast activity. Our in vivo findings showed that TPPU inhibits osteoclast activity and neutrophil adhesion and enhances periodontal tissue repair and regeneration.

CONCLUSIONS

TPPU promotes local regeneration in periodontitis by inhibiting inflammation and bone resorption. Thus, targeting soluble epoxide hydrolase represents an endogenous regenerative strategy for periodontitis treatment.

Effect of Er: YAG laser therapy in non-surgical periodontal treatment: an umbrella review

AIM

The current umbrella review aimed to summarize the effect of erbium-doped yttrium aluminum garnet (Er: YAG) laser adjunct with the conventional non-surgical periodontal treatment which was evidenced from available systematic reviews.

METHODS

An extensive literature search was piloted by two independent reviewers in the PubMed, Scopus, Science Direct, and Google Scholar databases. The search was limited to the English language from 2011 to 2023 years. The methodological quality of systematic reviews 2 (AMSTAR 2) guideline was followed to evaluate the risk of bias for the selected studies. Cohen's kappa statistic was implemented to evaluate the level of agreement to assess the risk of bias in the selected studies.

RESULTS

A total of 472 studies were initially identified. After removing the duplicates and screening, a total of four studies were selected for the current overview. Based on the quality assessment tool, each study scored as high, moderate, low, and critically low-quality study following AMSTAR 2 tool. Inter-rater reliability by Cohen's Kappa statistics showed near-perfect agreement (0.95) between the two reviewers.

CONCLUSION

Even though weak evidence of effectiveness was observed for Er: YAG laser application in non-surgical periodontal treatment, the clinical benefits are still lacking.

The Anti-Inflammatory Effect of SDF-1 Derived Peptide on Porphyromonas gingivalis Infection via Regulation of NLRP3 and AIM2 Inflammasome

(1) Background: Peptides are appealing as pharmacological materials because they are easily produced, safe, and tolerable. Despite increasing gum-care awareness, periodontitis is still prevalent and is influenced by factors like high sugar consumption, smoking, and aging. Porphyromonas gingivalis is considered a major etiologic agent of periodontitis and activates the NLR family pyrin domain containing 3 (NLRP3) but is absent in melanoma 2 (AIM2) inflammasomes, resulting in pro-inflammatory cytokine release. (2) Methods: We examined the anti-inflammatory effects of 18 peptides derived from human stromal cell-derived factor-1 (SDF-1) on THP-1 macrophages. Inflammation was induced by P. gingivalis, and the anti-inflammatory effects were analyzed using molecular biological techniques. In a mouse periodontitis model, alveolar bone resorption was assessed using micro-CT. (3) Results: Of the 18 SDF-1-derived peptides, S10 notably reduced IL-1β and TNF-α secretion. S10 also diminished the P. gingivalis-induced expression of NLRP3, AIM2, ASC (apoptosis-associated speck-like protein), caspase-1, and IL-1β. Furthermore, S10 attenuated the enhanced TLR (toll-like receptor) signaling pathway and decreased the phosphorylation of nuclear factor-κB (NF-κB) and mitogen-activated protein kinases (MAPKs). In addition, S10 mitigated alveolar bone loss in our P. gingivalis-induced mouse model of periodontitis. (4) Conclusions: S10 suppressed TLR/NF-κB/NLRP3 inflammasome signaling and the AIM2 inflammasome in our P. gingivalis-induced murine periodontitis model, which suggests that it has potential use as a therapeutic treatment for periodontitis.

Pregnancy Outcomes and Maternal Periodontal Diseases: The Unexplored Connection

In the early 20th century, numerous in-vitro studies, animal studies, epidemiological studies, and human trials have attempted to demonstrate the interrelationship between pregnancy outcomes and maternal periodontal disease. This review aims to shed light on the unexplored connections between pregnancy outcomes and maternal periodontal diseases. A literature search was conducted using electronic databases such as PubMed, Scopus, Google Scholar, Web of Science, and Embase. Our research focuses on the role of epigenetics, maternal vitamin D status, stress levels, genetic factors, innate immunity, pattern recognition receptors, and any potential paternal influence, and their possible connections to maternal periodontal disease. Although the precise etiologies and pathogenic mechanisms of the adverse pregnancy outcomes remain obscure, substantial affirmation of the inter-relationship between maternal periodontal diseases and adverse pregnancy outcomes may prove to be of public health relevance as periodontitis can certainly be prevented and treated. Maternal periodontal disease may augment the probability of jeopardizing maternal health causing adverse effects on the pregnancy and neonatal morbidity. Hence, emphasis should be placed on an early diagnosis and management of periodontal diseases. Routine oral health evaluation during prenatal care should be encouraged to combat complications. Ensuing endeavors should be undertaken to help find plausible mechanisms keeping in view the future research domains and new pathways.

Diagnostic measures for monitoring and follow-up in periodontology and implant dentistry

This review discusses the role of diagnostic measures in the lifelong management of periodontal disease and peri-implant complications. After active treatment, these conditions require regular monitoring of the supporting structures of teeth and dental implants to assess bone and soft tissue health over time. Several clinical measures have been developed for the routine assessment of periodontal and peri-implant tissues, including periodontal and peri-implant probing, bleeding on probing, intraoral radiography, biomarker analysis, and microbiological testing. This review highlights the evolution of diagnostic practices, integrating traditional methods with emerging technologies such as resonance frequency analysis and ultrasound imaging to provide a holistic view of peri-implant health assessment. In addition to objective measurements, patient risk factors are considered. The goals of periodontal and peri-implant maintenance are to control disease activity and stabilize tissues through supportive care, which includes diagnostic measures at follow-up visits. This enables clinicians to monitor treatment outcomes, assess health status, and detect recurrence or progression early through routine evaluation, allowing additional interventions, including adjustment of supportive therapy intervals, to further improve and maintain periodontal and peri-implant stability over time.

Classification of Periapical and Bitewing Radiographs as Periodontally Healthy or Diseased by Deep Learning Algorithms

Objectives The aim of this artificial intelligence (AI) study was to develop a deep learning algorithm capable of automatically classifying periapical and bitewing radiography images as either periodontally healthy or unhealthy and to assess the algorithm's diagnostic success. Materials and methods The sample of the study consisted of 1120 periapical radiographs (560 periodontally healthy, 560 periodontally unhealthy) and 1498 bitewing radiographs (749 periodontally healthy, 749 periodontally ill). From the main datasets of both radiography types, three sub-datasets were randomly created: a training set (80%), a validation set (10%), and a test set (10%). Using these sub-datasets, a deep learning algorithm was developed with the YOLOv8-cls model (Ultralytics, Los Angeles, California, United States) and trained over 300 epochs. The success of the developed algorithm was evaluated using the confusion matrix method. Results The AI algorithm achieved classification accuracies of 75% or higher for both radiograph types. For bitewing radiographs, the sensitivity, specificity, precision, accuracy, and F1 score values were 0.8243, 0.7162, 0.7439, 0.7703, and 0.7821, respectively. For periapical radiographs, the sensitivity, specificity, precision, accuracy, and F1 score were 0.7500, 0.7500, 0.7500, 0.7500, and 0.7500, respectively. Conclusion The AI models developed in this study demonstrated considerable success in classifying periodontal disease. Future applications may involve employing AI algorithms for assessing periodontal status across various types of radiography images and for automated disease detection.

Changes in oral health during aging in a novel non-human primate model

Oral health plays a significant role in the quality of life and overall well-being of the aging population. However, age-related changes in oral health are not well understood due to challenges with current animal models. In this study, we analyzed the oral health and microbiota of a short-lived non-human primate (i.e., marmoset), as a step towards establishing a surrogate for studying the changes that occur in oral health during human aging. We investigated the oral health of marmosets using cadaveric tissues in three different cohorts: young (aged ≤6 years), middle-aged, and older (>10 years) and assessed the gingival bacterial community using analyses of the V3-V4 variable region of 16S rRNA gene. The oldest cohort had a significantly higher number of dental caries, increased dental attrition/erosion, and deeper periodontal pocket depth scores. Oral microbiome analyses showed that older marmosets had a significantly greater abundance of Escherichia-Shigella and Propionibacterium, and a lower abundance of Agrobacterium/Rhizobium at the genus level. Alpha diversity of the microbiome between the three groups showed no significant differences; however, principal coordinate analysis and non-metric multidimensional scaling analysis revealed that samples from middle-aged and older marmosets were more closely clustered than the youngest cohort. In addition, linear discriminant analysis effect size (LEFSe) identified a higher abundance of Esherichia-Shigella as a potential pathogenic biomarker in older animals. Our findings confirm that changes in the oral microbiome are associated with a decline in oral health in aging marmosets. The current study suggests that the marmoset model recapitulates some of the changes in oral health associated with human aging and may provide opportunities for developing new preventive strategies or interventions which target these disease conditions.

Triptolide mitigates the inhibition of osteogenesis induced by TNF-α in human periodontal ligament stem cells via the p-IκBα/NF-κB signaling pathway: an in-vitro study

BACKGROUND

Triptolide is a widely utilized natural anti-inflammatory drug in clinical practice. Aim of this study was to evaluate effects of triptolide on hPDLSCs osteogenesis in an inflammatory setting and to investigate underlying mechanisms.

METHODS

Using the tissue block method to obtain hPDLSCs from extracted premolar or third molar. Flow cytometry, osteogenic and adipogenic induction were carried out in order to characterise the features of the cells acquired. hPDLSC proliferative activity was assessed by CCK-8 assay to determine the effect of TNF-α and/or triptolide. The impact of triptolide on the osteogenic differentiation of hPDLSCs was investigated by ALP staining and quantification. Osteogenesis-associated genes and proteins expression level were assessed through PCR and Western blotting assay. Finally, BAY-117,082 was used to study the NF-κB pathway.

RESULTS

In the group treated with TNF-α, there was an elevation in inflammation levels while osteogenic ability and the expression of both osteogenesis-associated genes and proteins decreased. In the group co-treated with TNF-α and triptolide, inflammation levels were reduced and osteogenic ability as well as the expression of both osteogenesis-associated genes and proteins were enhanced. At the end of the experiment, both triptolide and BAY-117,082 exerted similar inhibitory effects on the NF-κB pathway.

CONCLUSION

The osteogenic inhibition of hPDLSCs by TNF-α can be alleviated through triptolide, with the involvement of the p-IκBα/NF-κB pathway in this mechanism.

Detection of periodontal bone loss patterns and furcation defects from panoramic radiographs using deep learning algorithm: a retrospective study

BACKGROUND

This retrospective study aimed to develop a deep learning algorithm for the interpretation of panoramic radiographs and to examine the performance of this algorithm in the detection of periodontal bone losses and bone loss patterns.

METHODS

A total of 1121 panoramic radiographs were used in this study. Bone losses in the maxilla and mandibula (total alveolar bone loss) (n = 2251), interdental bone losses (n = 25303), and furcation defects (n = 2815) were labeled using the segmentation method. In addition, interdental bone losses were divided into horizontal (n = 21839) and vertical (n = 3464) bone losses according to the defect patterns. A Convolutional Neural Network (CNN)-based artificial intelligence (AI) system was developed using U-Net architecture. The performance of the deep learning algorithm was statistically evaluated by the confusion matrix and ROC curve analysis.

RESULTS

The system showed the highest diagnostic performance in the detection of total alveolar bone losses (AUC = 0.951) and the lowest in the detection of vertical bone losses (AUC = 0.733). The sensitivity, precision, F1 score, accuracy, and AUC values were found as 1, 0.995, 0.997, 0.994, 0.951 for total alveolar bone loss; found as 0.947, 0.939, 0.943, 0.892, 0.910 for horizontal bone losses; found as 0.558, 0.846, 0.673, 0.506, 0.733 for vertical bone losses and found as 0.892, 0.933, 0.912, 0.837, 0.868 for furcation defects (respectively).

CONCLUSIONS

AI systems offer promising results in determining periodontal bone loss patterns and furcation defects from dental radiographs. This suggests that CNN algorithms can also be used to provide more detailed information such as automatic determination of periodontal disease severity and treatment planning in various dental radiographs.

Long-term results of regenerative treatment of intrabony defects: a cohort study with 5-year follow-up

BACKGROUND

The aim of this retrospective cohort study was to evaluate the long-term clinical and radiographic outcomes and survival of teeth in periodontal regenerative treatment of intrabony defects using combined enamel matrix protein derivative (EMD) and deproteinized porcine bone mineral (DPBM) compared to EMD alone.

METHODS

A total of 333 intrabony defects in 176 patients (mean age: 54.7 ± 8.9 years) were followed-up for 58.6 ± 11.2 (range, 25-78) months after periodontal regenerative treatment. Changes in clinical (pocket probing depth and clinical attachment level) and radiographic (defect depth and defect width) parameters were analyzed using serial periapical radiographs. Kaplan-Meier and multivariate Cox proportional-hazards regression analyses for tooth loss were also performed.

RESULTS

Compared to periodontal surgery with EMD alone with a mean follow-up of 5 years, combined EMD and DPBM showed significantly better gain in clinical attachment level (EMD and DPBM: 2.8 ± 2.3 mm vs. EMD alone: 2.2 ± 2.2 mm) and reduction in probing pocket depth (EMD and DPBM: 2.8 ± 1.8 mm vs. EMD alone: 2.3 ± 1.8 mm), defect depth (EMD and DPBM: 2.5 ± 2.4 mm vs. EMD alone: 2.0 ± 2.4 mm) and defect width (EMD and DPBM: 0.6 ± 1.0 mm vs. EMD alone: 0.2 ± 1.3 mm). The overall survival rates of the teeth were 91.48% and 95.20% in the patient- and tooth-based analyses, respectively, showing no statistically significant difference.

CONCLUSIONS

Within the limitations of the current study, combined EMD and DPBM offered additional clinical and radiographic benefits over a mean of 5 years compared to EMD alone. However, tooth loss did not differ significantly between the two groups.

CLINICAL RELEVANCE

Compared to EMD alone, combined EMD and DPBM for intrabony defects has additional clinical advantages; however, patient- and tooth-related risk factors must be considered when performing periodontal regenerative surgery.

Effect of adjuvant probiotic therapy (Lactobacillus reuteri) in the treatment of periodontitis associated with diabetes mellitus: clinical, controlled, and randomized study

OBJECTIVES

Subgingival instrumentation (SI) with probiotics may be a proposal for the treatment of periodontitis (P), for patients with type 2 diabetes mellitus (T2DM). The Lactobacillus reuteri probiotic as an adjunctive therapy in the treatment of P associated with T2DM was evaluated.

MATERIALS AND METHODS

Forty diabetic participants diagnosed with P (stage III and IV, grade B) were randomized into SI + Placebo (n = 20): subgingival instrumentation plus placebo lozenges and SI + Probi (n = 20): subgingival instrumentation plus probiotics. Probing depth (PD), gingival recession (GR), clinical attachment level (CAL), plaque index (PI), bleeding on probing (BoP), and PISA index were performed at baseline and 30, 90, and 180 days. Cytokine concentration in the gingival crevicular fluid, subgingival biofilm sample, and LDL and HDL subfractions were evaluated.

RESULTS

In the deep pockets, PD in SI + Probi showed increased values (p = 0.02) compared to SI + Placebo at 90 days. For CAL, SI + Probi showed increased values compared to SI + Placebo, with a significant difference at 30 days (p = 0.03), 90 days (p = 0.02), and 180 days (p = 0.04). At #PD ≥ 7 mm, SI + Probi had a more frequent number of sites (p = 0.03) compared to SI + Placebo only at baseline. For the PISA, SI + Probi showed a significant difference (p = 0.04) compared to SI + Placebo at 90 days. For cytokines, SI + Probi showed higher quantification than SI + Placebo for IL-10 (p < 0.001) at 90 days, IL-12 (p = 0.010) at 90 days, IL-1β (p = 0.035) at 90 days, and IL-8 (p = 0.003) at baseline. SI + Placebo showed higher quantification of IL-1β (p = 0.041) compared to SI + Probi only at 30 days. There was a reduction in all microbial complexes. SI + Probi improved LDL size (246.7 nm vs 260.4 nm; p < 0.001), while large HDL subfractions were reduced aft 180 days of treatment (24.0% vs 20.3%; p = 0.022) when compared with SI + Placebo; this response was dependent of probiotics (1.0 mg/dL vs - 6.2 mg/dL; p = 0.002).

CONCLUSION

Subgingival instrumentation improved the clinical periodontal parameters in patients with T2DM. The use of L. reuteri probiotics had no additional effects compared with the placebo; however, there was a positive effect on the lipoprotein subfraction.

CLINICAL RELEVANCE

Scientific rationale for study: subgingival instrumentation with probiotics may be a proposal for the treatment of periodontitis (P), especially for patients with type 2 diabetes mellitus (T2DM).

PRINCIPAL FINDINGS

the use of L. reuteri probiotics had no additional effects compared with the placebo; however, there was a positive effect on the lipoprotein subfraction.  Practical implications: L. reuteri as an adjunct to subgingival instrumentation may have significant therapeutic implications in dyslipidemia.

Effect of artesunate on cardiovascular complications in periodontitis in a type I diabetes rat model and related mechanisms

PURPOSE

Both cardiovascular disease and periodontitis are complications of diabetes that have a great impact on human life and health. Our previous research found that artesunate can effectively improve cardiovascular disease in diabetes and has an inhibitory effect on periodontal disease. Therefore, the present study aimed to explore the potential therapeutic possibility of artesunate in the protection against cardiovascular complications in periodontitis with type I diabetes rats and to elucidate the possible underlying mechanisms.

METHODS

Sprague‒Dawley rats were randomly divided into the healthy, diabetic, periodontitis, diabetic with periodontitis, and artesunate treatment groups (10, 30, and 60 mg/kg, i.g.). After artesunate treatment, oral swabs were collected and used to determine changes in the oral flora. Micro-CT was performed to observe changes in alveolar bone. Blood samples were processed to measure various parameters, while cardiovascular tissues were evaluated by haematoxylin-eosin, Masson, Sirius red, and TUNEL staining to observe fibrosis and apoptosis. The protein and mRNA expression levels in the alveolar bone and cardiovascular tissues were detected using immunohistochemistry and RT‒PCR.

RESULTS

Diabetic rats with periodontitis and cardiovascular complications maintained heart and body weight but exhibited reduced blood glucose levels, and they were able to regulate blood lipid indicators at normal levels after artesunate treatment. The staining assays suggested that treatment with 60 mg/kg artesunate has a significant therapeutic effect on myocardial apoptotic fibrosis. The high expression of NF-κB, TLR4, VEGF, ICAM-1, p38 MAPK, TGF-β, Smad2, and MMP9 in the alveolar bone and cardiovascular tissue in the type I diabetes and type I diabetes with periodontitis rat models was reduced after treatment with artesunate in a concentration-dependent manner. Micro-CT showed that treatment with 60 mg/kg artesunate effectively alleviated alveolar bone resorption and density reduction. The sequencing results suggested that each model group of rats had vascular and oral flora dysbiosis, but artesunate treatment could correct the dysbacteriosis.

CONCLUSIONS

Periodontitis-related pathogenic bacteria cause dysbiosis of the oral and intravascular flora in type I diabetes and aggravate cardiovascular complications. The mechanism by which periodontitis aggravates cardiovascular complications involves the NF-κB pathway, which induces myocardial apoptosis, fibrosis, and vascular inflammation.

Effect of photobiomodulation adjunct to periodontal therapy on individuals with type 2 diabetes mellitus regarding periodontal clinical parameters: a systematic review and meta-analysis

The purpose of this study is to evaluate the scientific evidence on the impact of photobiomodulation adjunct to non-surgical periodontal treatment on individuals with type 2 diabetes mellitus (T2DM). The Preferred Reporting Items for Systematic Reviews and Meta-analyses statement was followed. A protocol was registered in the International Prospective Registry of Systematic Reviews (PROSPERO #CRD42022310756). The research was carried out in seven databases, with no restrictions regarding the year of publication. Our work included studies that compared periodontal clinical parameters among individuals undergoing non-surgical periodontal therapy associated with photobiomodulation and a control group of individuals undergoing non-surgical periodontal treatment. Study selection, data extraction, and risk of bias assessment (RoB 2.0) were performed by two review authors. Meta-analysis was performed. Mean difference (MD) and a 95% confidence interval (CI) were provided. Three hundred forty-one studies were identified, of which eight studies were included. The meta-analysis demonstrated that photobiomodulation adjunctive to periodontal therapy in individuals with diabetes resulted in a greater reduction in probing depth and greater attachment gain in comparison to periodontal treatment alone (p < 0.05). The included studies exhibited a low risk of bias. Photobiomodulation adjunct to periodontal therapy contributes to the improvement of periodontal clinical parameters in individuals with T2DM.

Analysis of Salivary Levels of IL-1β, IL17A, OPG and RANK-L in Periodontitis Using the 2017 Classification of Periodontal Diseases-An Exploratory Observational Study

Periodontitis is a chronic disease with a high overall prevalence. It involves a complex interplay between the immune-inflammatory pathways and biofilm changes, leading to periodontal attachment loss. The aims of this study were (i) to assess whether the salivary IL-1β, IL-17A, RANK-L and OPG levels have the potential to discriminate between the mild and severe periodontitis conditions; and (ii) to enable diagnostic/prognostic actions to differentiate between distinct levels of the disease. The analysis of the clinical parameters and the evaluation of the salivary immunomediators levels by means of a multiplex flow assay revealed a statistically significantly higher level of IL-1β in the periodontitis III/IV patients, as well as a higher level of RANK-L in the periodontitis III/IV and I/II patients, when compared to the healthy controls. Furthermore, the grade C periodontitis patients presented a significantly higher level of RANK-L compared to the grade B and grade A patients. In the grade C patients, IL-1β had a positive correlation with the PPD and CAL indices and RANK_L had a positive correlation with CAL. The evidence emerging from this study associates the salivary IL-1β and RANK-L levels with an advanced stage of periodontitis, stage III/IV, and with grade C, suggesting the possible cooperative action of both in the inflammatory and bone loss events. In addition to IL-1β, RANK-L could be considered a combined diagnostic biomarker for periodontitis.

The Contribution of the Human Oral Microbiome to Oral Disease: A Review

The oral microbiome is an emerging field that has been a topic of discussion since the development of next generation sequencing and the implementation of the human microbiome project. This article reviews the current literature surrounding the oral microbiome, briefly highlighting most recent methods of microbiome characterization including cutting edge omics, databases for the microbiome, and areas with current gaps in knowledge. This article also describes reports on microorganisms contained in the oral microbiome which include viruses, archaea, fungi, and bacteria, and provides an in-depth analysis of their significant roles in tissue homeostasis. Finally, we detail key bacteria involved in oral disease, including oral cancer, and the current research surrounding their role in stimulation of inflammatory cytokines, the role of gingival crevicular fluid in periodontal disease, the creation of a network of interactions between microorganisms, the influence of the planktonic microbiome and cospecies biofilms, and the implications of antibiotic resistance. This paper provides a comprehensive literature analysis while also identifying gaps in knowledge to enable future studies to be conducted.

Telocytes regulate macrophages in periodontal disease

Telocytes (TCs) or interstitial cells are characterised in vivo by their long projections that contact other cell types. Although telocytes can be found in many different tissues including the heart, lung, and intestine, their tissue-specific roles are poorly understood. Here we identify a specific cell signalling role for telocytes in the periodontium whereby telocytes regulate macrophage activity. We performed scRNA-seq and lineage tracing to identify telocytes and macrophages in mouse periodontium in homeostasis and periodontitis and carried out hepatocyte growth factor (HGF) signalling inhibition experiments using tivantinib. We show that telocytes are quiescent in homeostasis; however, they proliferate and serve as a major source of HGF in periodontitis. Macrophages receive telocyte-derived HGF signals and shift from an M1 to an M1/M2 state. Our results reveal the source of HGF signals in periodontal tissue and provide new insights into the function of telocytes in regulating macrophage behaviour in periodontitis through HGF/Met cell signalling, which may provide a novel approach in periodontitis treatment.

Low-intensity pulsed ultrasound promotes periodontal regeneration in a beagle model of furcation involvement

Objective: To evaluate the regeneration potential of periodontitis tissue treated by low-intensity pulsed ultrasound (LIPUS) combined with the guided tissue regeneration (GTR) technique in a beagle model of furcation involvement (FI).

Background: Achieving predictable regeneration remains a clinical challenge for periodontitis tissue due to the compromised regenerative potential caused by chronic inflammation stimulation. LIPUS, an FDA-approved therapy for long bone fracture and non-unions, has been demonstrated effective in the in vitro attenuation of inflammation-induced dysfunction of periodontal ligament stem cells (PDLSCs), the key cells contributing to periodontal regeneration. However, the in vivo effect of LIPUS on periodontitis tissue is rarely reported.

Methods: A beagle model of FI was established, and the experimental teeth were randomly assigned into three groups: control group, GTR group, and GTR+LIPUS group. Radiographic examinations were performed, and clinical periodontal parameters were recorded to reflect the periodontal condition of different groups. Histological analyses using H&amp;E and Masson’s staining were conducted to evaluate the periodontal tissue regeneration.

Results: LIPUS could enhance new periodontal bone formation and bone matrix maturity in FI after GTR treatment. Moreover, clinical assessment and histomorphometric analyses revealed less inflammatory infiltration and superior vascularization within bone grafts in the LIPUS treatment group, indicating the anti-inflammatory and pro-angiogenic effects of LIPUS in FI.

Conclusion: Our investigation on a large animal model demonstrated that LIPUS is a promising adjunctive approach for the regeneration of periodontitis tissue, paving a new avenue for LIPUS application in the field of periodontal regenerative medicine.

Surface Topography-Adaptive Robotic Superstructures for Biofilm Removal and Pathogen Detection on Human Teeth

The eradication of biofilms remains an unresolved challenge across disciplines. Furthermore, in biomedicine, the sampling of spatially heterogeneous biofilms is crucial for accurate pathogen detection and precise treatment of infection. However, current approaches are incapable of removing highly adhesive biostructures from topographically complex surfaces. To meet these needs, we demonstrate magnetic field-directed assembly of nanoparticles into surface topography-adaptive robotic superstructures (STARS) for precision-guided biofilm removal and diagnostic sampling. These structures extend or retract at multilength scales (micro-to-centimeter) to operate on opposing surfaces and rapidly adjust their shape, length, and stiffness to adapt and apply high-shear stress. STARS conform to complex surface topographies by entering angled grooves or extending into narrow crevices and "scrub" adherent biofilm with multiaxis motion while producing antibacterial reagents on-site. Furthermore, as the superstructure disrupts the biofilm, it captures bacterial, fungal, viral, and matrix components, allowing sample retrieval for multiplexed diagnostic analysis. We apply STARS using automated motion patterns to target complex three-dimensional geometries of ex vivo human teeth to retrieve biofilm samples with microscale precision, while providing "toothbrushing-like" and "flossing-like" action with antibacterial activity in real-time to achieve mechanochemical removal and multikingdom pathogen detection. This approach could lead to autonomous, multifunctional antibiofilm platforms to advance current oral care modalities and other fields contending with harmful biofilms on hard-to-reach surfaces.

The role of endoplasmic reticulum stress in the pathophysiology of periodontal disease

The endoplasmic reticulum (ER) is a principal organelle for folding, post-translational modifications and transport of secretory, luminal, and membrane proteins. ER stress is a condition induced by the accumulation of unfolded or misfolded proteins owing to a variety of physiological and pathological phenomena. To overcome the deleterious effects of ER stress, unfolded protein response (UPR) is initiated to translocate and remove the misfolded and accumulated proteins. Plenty of evidence shows the correlation between ER stress/UPR and the pathology of inflammatory disease. Periodontal disease is a chronic inflammatory disease characterized by the irreversible destruction of periodontal tissues, which associates with the onset and progress of several systemic diseases. Periodontopathic bacterium and pro-inflammatory mediators play a pivotal role in the progress of periodontal disease. Besides, cigarette smoke has long been associated with periodontal disease. As an inflammatory disorder of the periodontium, periodontal disease is highly related to ER stress. In this review, we provide an overview of the pathophysiological effect of ER stress on periodontal disease through five aspects as follow: ER stress and periodontal tissue remodeling, including both soft tissue and hard tissue; ER stress and the inflammation; ER stress and systematic effect during the periodontal disease; last but not least, ER stress and the autophagic apoptosis in cells.

Xanthine Derivative KMUP-1 Attenuates Experimental Periodontitis by Reducing Osteoclast Differentiation and Inflammation

Periodontitis is an inflammatory disease of gum that may predispose to serious systemic complications such as diabetes and cardiovascular diseases. Activation of macrophages and osteoclasts around periodontal tissue can accelerate gum inflammation. In addition, alteration of cyclic nucleotide levels is associated with the severity of periodontitis. Our previous study has shown that KMUP-1, a xanthine derivative exhibiting phosphodiesterase inhibition and soluble guanylyl cyclase activation, can inhibit lipopolysaccharide (LPS)-induced inflammation and receptor activator of nuclear factor kappa-Β ligand (RANKL)-induced osteoclastogenesis. This study was aimed to investigate whether KMUP-1 could attenuate periodontitis both in vitro and in vivo. In vitro, the protective effect of KMUP-1 on inflammation and osteoclastogenesis was investigated in RANKL-primed RAW264.7 cells treated by Porphyromonas gingivalis LPS (PgLPS). The results showed that KMUP-1 attenuated PgLPS-induced osteoclast differentiation as demonstrated by decreased TRAP-positive multinuclear cells and TRAP activity. This reduction of osteoclast differentiation by KMUP-1 was reversed by KT5823, a protein kinase G inhibitor. Similarly, pro-inflammatory cytokine levels induced by PgLPS were inhibited by KMUP-1 in a dose-dependent manner whereas reversed by KT5823. Mechanistically, suppression of MAPKs, PI3K/Akt, and NF-κB signaling pathways and decrease of c-Fos and NFATc1 expression in osteoclast precursors by KMUP-1 may mediate its protective effect. In vivo, two models of periodontitis in rats were induced by gingival injections of PgLPS and ligature placement around molar teeth, respectively. Our results showed that KMUP-1 inhibited alveolar bone loss in both rat models, and this effect mediated at least partly by reduced osteoclastogenesis. In conclusion, our study demonstrated the therapeutic potential of KMUP-1 on periodontitis through suppression of inflammation and osteoclast differentiation.

A Cross-Sectional Study for Association between Periodontitis and Benign Prostatic Hyperplasia Using the Korean Genome and Epidemiology Study Data

Recently, several studies have suggested the relationship between periodontitis and prostatic disease. However, epidemiological studies on the association between periodontitis and benign prostatic hyperplasia (BPH) are scarce. Hence, we aimed to identify the association between the two diseases using data from the Korean Genome and Epidemiology Study. Among the 173,209 participants, 3297 men with periodontitis and 35,292 controls (without periodontitis) were selected. The history of BPH in participants with periodontitis and the controls were also investigated. Two-tailed analyses, independent t-tests, and chi-square tests were used for statistical analysis. The adjusted odds ratio (OR) for BPH was 1.50 (95% confidence interval, 1.35–1.68; p < 0.001) after adjusting for past medical histories. The adjusted OR for BPH was 1.57 (95% confidence interval, 1.41–1.76; p < 0.001) after adjusting for anthropometric and laboratory data. Collectively, this study provides evidence that periodontitis is associated with BPH. This finding supports the use of regular dental checkups and periodontal treatments to reduce the prevalence and progression of BPH.

Postoperative anti-inflammatory efficacy of 2% saline rinses and a herbal- mouthwash after non-surgical periodontal therapy for the management of periodontal inflammation in young adults with chlorhexidine allergy: A randomized controlled trial

AIM

The present randomized controlled trial assessed the postoperative anti-inflammatory efficacy of 2% saline rinses (SR) and a herbal- mouthwash (HMW) after non-surgical periodontal therapy (NSPT) for the management of periodontal inflammation in patients with chlorhexidine (CHX) allergy.

MATERIALS AND METHODS

Patients with periodontal inflammation with and without self-reported CHX-allergy were included. All patients underwent non-surgical periodontal therapy (NSPT). Patients were randomly divided into three groups. In the SR and HMW groups, 2% SR, and a HMW, respectively were prescribed. In Group-3 (CHX-group), patients without CHX allergy were included and were prescribed 0.12% CHX. In all groups, plaque index (PI), gingival index (GI), probing depth (PD), clinical attachment loss (AL) and marginal bone loss were measured at baseline. Clinical periodontal parameters were re-assessed at 6-weeks' follow-up. P<0.01 were considered statistically significant.

RESULTS

Thirteen, 12 and 12 patients were included in the SR, HMW and CHX groups, respectively. At baseline clinical and radiographic periodontal parameters were comparable in all groups. In all groups, PI (P<0.01), GI (P<0.01) and PD (P<0.01) were significantly higher at baseline compared with their respective values at 6-weeks of follow-up. There was no significant difference in clinical AL at all time intervals in all groups. There was no significant correlation between periodontal parameters and age, gender and daily toothbrushing/flossing in all groups.

CONCLUSION

In young adults with self-reported CHX-allergy, herbal-mouthwashes and/or 2% SR are suitable postoperative prescriptions after NSPT.

Effects of Periodontal Endoscopy-Assisted Nonsurgical Treatment of Periodontitis: Four-Month Results of a Randomized Controlled Split-Mouth Pilot Study

Objective. Although the therapeutic effects of nonsurgical periodontal therapy (NSPT) are well established, the clinical benefits of the additional use of periodontal endoscopy (PE) remain controversial. Therefore, this randomized controlled split-mouth pilot study evaluated the effect of NSPT using PE versus NSPT without nPE on bleeding on probing (BOP) in sites with probing depth (PD)≥4 mm (primary outcome), PD, clinical attachment level (CAL), number of hard deposits (HDs), and treatment time per tooth (TrT). Methods. Two calibrated operators performed NSPT in twenty periodontitis patients, randomized into two quadrants for PE or nPE treatment. BOP, PD, and CAL were recorded at the first visit for NSPT (T0) and during reevaluation (T1: mean (SD) 119.7 (24.6) days after T0). The average TrT and the number of sites with HDs were documented at T0. Results. For BOP, no significant differences were found at the patient’s level (10/10 (male/female); aged 54.3 (10.9) years) neither within or between the groups. At tooth surface level, a lower number of surfaces with BOP $\left(p=0.026\right)$ was observed in nPE. CAL and PD improved significantly during NSPT in both groups $\left(p\le 0.001\right)$ , with higher PD reduction $\left(p<0.001\right)$ and CAL gain $\left(p<0.001\right)$ in nPE. There are significantly longer TrT $\left(p<0.001\right)$ and more surfaces with subgingival HDs evident in PE at T0 $\left(p=0.001\right)$ . Conclusion. Whereas subgingival HDs can be visually detected with PE during NSPT, no additional clinical benefits regarding BOP, PD, or CAL were notable compared to conventional systematic periodontal instrumentation. Additionally, PE-assisted NSPT required a longer treatment time.

Effects of baicalin on the proliferation and expression of OPG and RANKL in human cementoblast-lineage cells

Background/purpose

Baicalin, a natural bioactive flavonoid extracted from Scutellaria baicalensis Georgi, mediates bone metabolism, and recent studies have revealed that it has cell signaling properties. However, its biological functions in cementoblasts still remain unclear. This study therefore aimed to investigate the effects of baicalin on bone resorption markers, including osteoprotegerin (OPG) and receptor activator of nuclear factor-κβ ligand (RANKL), in human cementoblast-lineage cells, as well as their proliferation ability.

Materials and methods

Human cementoblast cell line (HCEM) cells were cultured and treated with 0, 0.01, 0.1, or 1 μM of baicalin. The proliferative capacity of cultured HCEM cells was analyzed using bromodeoxyuridine immunoassay and cell counting. The baicalin effect on OPG and RANKL expression was determined using quantitative polymerase chain reaction (qPCR) and western blotting. Furthermore, OPG expression was measured in 1 μM baicalin-treated HCEM cells in the presence or absence of the Wnt signaling pathway inhibitor, Dickkopf (Dkk)-1, using qPCR and western blotting.

Results

The addition of 0.01, 0.1, and 1 μM of baicalin did not significantly change the proliferative capacity of cultured HCEM cells. Compared with the non-supplemented group, baicalin increased and suppressed OPG and RANKL gene and protein expression, respectively, in a concentration-dependent manner. OPG mRNA and protein expression levels were increased by 1 μM baicalin, which was suppressed by Dkk-1 addition.

Conclusion

Baicalin enhanced OPG expression in HCEM cells through the Wnt/beta-catenin signaling pathway, which could contribute to periodontal tissue regeneration.

Interdental Plaque Microbial Community Changes under In Vitro Violet LED Irradiation

Oral microbiome dysbiosis has important links to human health and disease. Although photodynamic therapy influences microbiome diversity, the specific effect of violet light irradiation remains largely unknown. In this study, we analyzed the effect of violet light-emitting diode (LED) irradiation on interdental plaque microbiota. Interdental plaque was collected from 12 human subjects, exposed to violet LED irradiation, and cultured in a specialized growth medium. Next-generation sequencing of the 16S ribosomal RNA genes revealed that α-diversity decreased, whereas β-diversity exhibited a continuous change with violet LED irradiation doses. In addition, we identified several operational taxonomic units that exhibited significant shifts during violet LED irradiation. Specifically, violet LED irradiation led to a significant reduction in the relative abundance of Fusobacterium species, but a significant increase in several species of oral bacteria, such as Veillonella and Campylobacter. Our study provides an overview of oral plaque microbiota changes under violet LED irradiation, and highlights the potential of this method for adjusting the balance of the oral microbiome without inducing antibiotic resistance.

Antimicrobial Mechanisms of Leucocyte- and Platelet Rich Fibrin Exudate Against Planktonic Porphyromonas gingivalis and Within Multi-Species Biofilm: A Pilot Study

Leucocyte- and platelet rich fibrin (L-PRF) is an autologous biomaterial used in regenerative procedures. It has an antimicrobial activity against P. gingivalis although the mechanism is not fully understood. It was hypothesized that L-PRF exudate releases hydrogen peroxide and antimicrobial peptides that inhibit P. gingivalis growth. Agar plate and planktonic culture experiments showed that the antimicrobial effect of L-PRF exudate against P. gingivalis was supressed by peroxidase or pepsin exposure. In developing multi-species biofilms, the antimicrobial effect of L-PRF exudate was blocked only by peroxidase, increasing P. gingivalis growth with 1.3 log genome equivalents. However, no effect was shown on other bacteria. Pre-formed multi-species biofilm trials showed no antimicrobial effect of L-PRF exudate against P. gingivalis or other species. Our findings showed that L-PRF exudate may release peroxide and peptides, which may be responsible for its antimicrobial effect against P. gingivalis. In addition, L-PRF exudate had an antimicrobial effect against P. gingivalis in an in vitro developing multi-species biofilm.

Highly Segregated Biocomposite Membrane as a Functionally Graded Template for Periodontal Tissue Regeneration

Guided tissue regeneration (GTR) membranes are used for treating chronic periodontal lesions with the aim of regenerating lost periodontal attachment. Spatially designed functionally graded bioactive membranes with surface core layers have been proposed as the next generation of GTR membranes. Composite formulations of biopolymer and bioceramic have the potential to meet these criteria. Chitosan has emerged as a well-known biopolymer for use in tissue engineering applications due to its properties of degradation, cytotoxicity and antimicrobial nature. Hydroxyapatite is an essential component of the mineral phase of bone. This study developed a GTR membrane with an ideal chitosan to hydroxyapatite ratio with adequate molecular weight. Membranes were fabricated using solvent casting with low and medium molecular weights of chitosan. They were rigorously characterised with scanning electron microscopy, Fourier transform infrared spectroscopy in conjunction with photoacoustic sampling accessory (FTIR-PAS), swelling ratio, degradation profile, mechanical tensile testing and cytotoxicity using human osteosarcoma and mesenchymal progenitor cells. Scanning electron microscopy showed two different features with 70% HA at the bottom surface packed tightly together, with high distinction of CH from HA. FTIR showed distinct chitosan dominance on top and hydroxyapatite on the bottom surface. Membranes with medium molecular weight showed higher swelling and longer degradation profile as compared to low molecular weight. Cytotoxicity results indicated that the low molecular weight membrane with 30% chitosan and 70% hydroxyapatite showed higher viability with time. Results suggest that this highly segregated bilayer membrane shows promising potential to be adapted as a surface layer whilst constructing a functionally graded GTR membrane on its own and for other biomedical applications.

Efficacy of erythritol powder air-polishing in active and supportive periodontal therapy: A systematic review and meta-analysis

OBJECTIVE

This systematic review aimed to analyse available evidence to answer two focused questions about the efficacy of erythritol powder air-polishing (EPAP) (i) as an adjunctive during active periodontal therapy (APT) and (ii) as an alternative to hand/ultrasonic instrumentation during supportive periodontal therapy (SPT). Additionally, microbiological outcomes and patient's comfort/perceptions were assessed as secondary outcomes.

METHODS

PubMed, Cochrane and Medline were searched for relevant articles published before February 2021 following PRISMA guidelines. The search was conducted by three independent reviewers, and the agreement was measured by Cohen's kappa score. Out of 1043 articles, eight randomized clinical trials were selected for systematic review and quantitative synthesis. Only periodontal parameters, such as clinical attachment level (CAL), probing pocket depth (PPD) and bleeding on probing (BoP), showed homogeneity and, thus, were selected for meta-analysis.

RESULTS

The improvement in PPD and BoP scores after using EPAP was comparable with hand/ultrasonic instrumentation during both APT and SPT. Significant CAL gain was achieved with EPAP during APT (0.16 mm, p < 0.02) compared with hand/ultrasonic instrumentation at the end point, whereas non-significant CAL gain was achieved during SPT. No differences were observed regarding microbiological outcomes between the two treatment modalities. However, EPAP inflicted less pain and was better perceived by the patients.

CONCLUSION

Erythritol powder air-polishing can substitute hand/ultrasonic instrumentation for SPT, and CAL gain is significantly improved when EPAP is used as an adjunct during APT. For microbiological outcomes, no significant differences were observed between the two approaches; however, EPAP was better tolerated by the patients than hand/ultrasonic instrumentation.

CLINICAL RELEVANCE

Erythritol powder air-polishing can be used as an adjunct during APT and as an alternative to conventional mechanical debridement during SPT.

Metagenomic Shotgun Sequencing Analysis of Canalicular Concretions in Lacrimal Canaliculitis Cases

Lacrimal canaliculitis is a rare infection of the lacrimal canaliculi with canalicular concretions formed by aggregation of organisms. Metagenomic shotgun sequencing analysis using next-generation sequencing has been used to detect pathogens directly from clinical samples. Using this technology, we report cases of successful pathogen detection of canalicular concretions in lacrimal canaliculitis cases. We investigated patients with primary lacrimal canaliculitis examined in the eye clinics of four hospitals from February 2015 to July 2017. Eighteen canalicular concretion specimens collected from 18 eyes of 17 patients were analyzed by shotgun metagenomics sequencing using the MiSeq platform (Illumina). Taxonomic classification was performed using the GenBank NT database. The canalicular concretion diversity was characterized using the Shannon diversity index. This study included 18 eyes (17 patients, 77.1 ± 6.1 years): 82.4% were women with lacrimal canaliculitis; canalicular concretions were obtained from 12 eyes using lacrimal endoscopy and six eyes using canaliculotomy with curettage. Sequencing analysis detected bacteria in all samples (Shannon diversity index, 0.05–1.47). The following genera of anaerobic bacteria (>1% abundance) were identified: Actinomyces spp. in 15 eyes, Propionibacterium spp., Parvimonas spp. in 11 eyes, Prevotella spp. in 9 eyes, Fusobacterium spp. in 6 eyes, Selenomonas spp. in 5 eyes, Aggregatibacter spp. in 3 eyes, facultative and aerobic bacteria such as Streptococcus spp. in 13 eyes, Campylobacter spp. in 6 eyes, and Haemophilus spp. in 3 eyes. The most common combinations were Actinomyces spp. and Streptococcus spp. and Parvinomonas spp. and Streptococcus spp., found in 10 cases. Pathogens were identified successfully using metagenomic shotgun sequencing analysis in patients with canalicular concretions. Canalicular concretions are polymicrobial with anaerobic and facultative, aerobic bacteria.

Computer-Assisted Detection of Cemento-Enamel Junction in Intraoral Ultrasonographs

The cemento-enamel junction (CEJ) is an important reference point for various clinical measurements in oral health assessment. Identifying CEJ in ultrasound images is a challenging task for dentists. In this study, a computer-assisted detection method is proposed to identify the CEJ in ultrasound images, based on the curvature change of the junction outlining the upper edge of the enamel and cementum at the cementum–enamel intersection. The technique consists of image preprocessing steps for image enhancement, segmentation, and edge detection to locate the boundary of the enamel and cementum. The effects of the image preprocessing and the sizes of the bounding boxes enclosing the CEJ were studied. For validation, the algorithm was applied to 120 images acquired from human volunteers. The mean difference of the best performance between the proposed method and the two raters’ measurements was an average of 0.25 mm with reliability ≥ 0.98. The proposed method has the potential to assist dental professionals in CEJ identification on ultrasonographs to provide better patient care.

Microbiologic Profiles of Patients with Dental Prosthetic Treatment and Periodontitis before and after Photoactivation Therapy-Randomized Clinical Trial

Fixed prosthodontic dental restorations can potentially affect the periodontal tissues and vice versa, the periodontium can influence the longevity and esthetic appearance of dental restorations. We proposed an investigation on total bacterial load, specific periodontal pathogens, and periodontal clinical parameters in patients with dental fixed prosthesis and different degrees of periodontal tissue loss that followed photoactivation therapy (PDT) adjunctive to scaling and root planing. The study was conducted on 160 subjects, which were randomly assigned to scaling and root planing (SRP) alone (52 subjects, 256 sites), SRP and chlorhexidine rinsing (58 subjects, 276 sites), and SRP plus PDT (50 subjects, 318 sites). Periodontal parameters (plaque index, bleeding on probing, probing depth, and clinical attachment loss), followed by total bacterial load and specific periodontal pathogens (Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythia, and Treponema denticola) were examined in each patient at baseline, one and six months after. PDT exerted significant improvements both in clinical and microbiological load after one month, and these results were maintained 6 months after when compared to chlorhexidine rinsing or SRP alone, especially in severe periodontitis cases. Photoactivation therapy as an adjunctive periodontal therapeutic method was efficient in offering supplementary periodontal improvements in the clinical and microbiological parameters of patients with fixed dental prosthesis, particularly in severe periodontitis cases.

MgO Nanoparticles-Incorporated PCL/Gelatin-Derived Coaxial Electrospinning Nanocellulose Membranes for Periodontal Tissue Regeneration

Electrospinning technique has attracted considerable attention in fabrication of cellulose nanofibrils or nanocellulose membranes, in which polycaprolactone (PCL) could be used as a promising precursor to prepare various cellulose nanofibril membranes for periodontal tissue regeneration. Conventional bio-membranes and cellulose films used in guided tissue regeneration (GTR) can prevent the downgrowth of epithelial cells, fibroblasts, and connective tissue in the area of tooth root but have limitations related to osteogenic and antimicrobial properties. Cellulose nanofibrils can be used as an ideal drug delivery material to encapsulate and carry some drugs. In this study, magnesium oxide (MgO) nanoparticles-incorporated PCL/gelatin core-shell nanocellulose periodontal membranes were fabricated using coaxial electrospinning technique, which was termed as Coaxial-MgO. The membranes using single-nozzle electrospinning technique, namely Blending-MgO and Blending-Blank, were used as control. The morphology and physicochemical property of these nanocellulose membranes were characterized by scanning electron microscopy (SEM), energy-dispersive spectrum of X-ray (EDS), transmission electron microscopy (TEM), contact angle, and thermogravimetric analysis (TGA). The results showed that the incorporation of MgO nanoparticles barely affected the morphology and mechanical property of nanocellulose membranes. Coaxial-MgO with core-shell fiber structure had better hydrophilic property and sustainable release of magnesium ion (Mg²⁺). CCK-8 cell proliferation and EdU staining demonstrated that Coaxial-MgO membranes showed better human periodontal ligament stem cells (hPDLSCs) proliferation rates compared with the other group due to its gelatin shell with great biocompatibility and hydrophilicity. SEM and immunofluorescence assay results illustrated that the Coaxial-MgO scaffold significantly enhanced hPDLSCs adhesion. In vitro osteogenic and antibacterial properties showed that Coaxial-MgO membrane enhanced alkaline phosphatase (ALP) activity, formation of mineralized nodules, osteogenic-related genes [ALP, collagen type 1 (COL1), runt-related transcription factor 2 (Runx2)], and high antibacterial properties toward Escherichia coli (E. coli) and Actinobacillus actinomycetemcomitans (A. a) when compared with controls. Our findings suggested that MgO nanoparticles-incorporated coaxial electrospinning PCL-derived nanocellulose periodontal membranes might have great prospects for periodontal tissue regeneration.

Peptidomic changes of saliva after nonsurgical treatment of stage I / II generalized periodontitis

OBJECTIVE

To explore the changes of peptidome profiles of saliva, serum and gingival crevicular fluid (GCF) before and after nonsurgical periodontal treatment in patients with generalized periodontitis (stage I / II).

SUBJECTS AND METHODS

Saliva, serum and GCF samples were collected from 17 patients at baseline (T₀ ), one week after ultrasonic supragingival scaling (T₁ ) and eight weeks after subgingival scaling and root planning (T₂ ). Matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) was carried out to detect changes in peptidomic profiles. Then nano-liquid chromatography-electrospray ionization-tandem mass spectrometry (nano-LC/ESI-MS/MS) was performed to identify potential peptide biomarkers.

RESULTS

Most of the peptides from the patients exhibited a decreasing trend from the time point of pre-treatment to that of post-treatment. Cluster analysis and scatter plots using these peptides indicated that salivary peptidome has an acceptable capability of reflecting the status of stage I / II generalized periodontitis. Seven of these peptides were successfully identified as α-1-antitrypsin, immunoglobulin κ variable 4-1, haptoglobin and immunoglobulin heavy constant γ2.

CONCLUSIONS

Certain peptides in saliva, serum and GCF were down-regulated after nonsurgical periodontal treatment, demonstrating the application prospects of saliva in monitoring and surveillance of periodontal diseases in both clinical settings and communities.

Leukotriene receptor antagonist reduces inflammation and alveolar bone loss in a rat model of experimental periodontitis

BACKGROUND

Leukotrienes (LTs) participate in the process of tissue damage in periodontal disease by leukocyte chemotaxis and osteoclastic activation. The activation of Cysteinyl-LT receptor is associated with increased expression of proinflammatory molecules and osteoclastogenesis. However, its implications on periodontal disease progression have not been studied. The present study evaluated the effect of the cysteinyl-LT receptor antagonist (montelukast [MT]) on ligature-induced experimental periodontitis (EP) in rats.

METHODS

Adult male Wistar rats were subjected to bilateral ligature-induced periodontitis and orally treated with MT (at doses of 10 or 30 mg/kg/d, MT10, and MT30, respectively). Sham animals had the ligatures immediately removed and received placebo treatment. Sets of animals were euthanized 7, 14, or 21 days after ligature placement and the mandibles were removed for macroscopic evaluation of alveolar bone loss (ABL). In addition, histological analysis of periodontal tissues, myeloperoxidase (MPO) activity of gingival tissues, and periodontal tissue expression of collagen type I, RUNX2, RANK, RANKL, OPG, BLT1, Cys-LTR1, LTA4H, and LTC4S were also analyzed.

RESULTS

MT significantly reduced ABL at 14 (MT10 and MT30) and 21 days (MT10) (P < 0.05), gingival MPO at 7 (MT10) and 14 days (MT30) (P < 0.05), LTA4H, BLT1 and LTC4S gene expression on day 14 day (MT30, P < 0.05) and increased RUNX2 expression on day 14 (MT30, P < 0.05).

CONCLUSION

Systemic therapy with MT decreases periodontal inflammation and ABL in ligature-induced periodontitis in rats.

The lived experience of performing a periodontal treatment in the context of general dentistry

Aim

To describe what characterises the lived experience of performing a periodontal treatment in the context of general dentistry.

Materials and methods

Three dental hygienists from general dentistry in Sweden, were purposively selected as participants and interviewed. The participants described a situation in which they had performed a periodontal treatment. The descriptions were analysed using the descriptive phenomenological psychological method.

Results

The general meaning structure of the lived experience of performing a periodontal treatment comprised five constituents, (a) an established treatment routine, (b) importance of oral hygiene, (c) self-awareness and motivation of the patient, (d) support and doubt, and (e) mechanical infection control. The periodontal treatment is perceived as being set prior to its commencement and as following established routines, in which the patients’ oral hygiene is experienced as a crucial part. The patients’ self-awareness and a supportive clinician are seen as important factors in motivating the patient towards positive behavioural change, although there is a presence of doubt in patients’ ability to maintain this positive change. Mechanical infection control is perceived as successful but sometimes difficult to perform.

Conclusions

Important, patient-related, factors are constituting the phenomenon of performing a periodontal treatment but an experience that the pre-existing standardised workflow influences patient management was also present.

Melanin pigmented gingival tissue impairs red-light lateral scattering for antimicrobial photodynamic therapy

Gingival melanin pigmentation is present in many African and Oriental descendant people and its occurrence in patients may interfere with the absorption and scattering of therapeutic doses of light. Antimicrobial photodynamic therapy (aPDT) is used as an adjunctive treatment for periodontitis and light irradiation may be impaired by tissue size and its melanin content. The aim of this clinical study was to measure the red-light attenuation in gingival tissue naturally pigmented with melanin. Ten patients with melanized gingival tissue were selected and irradiated by 100 mW red laser. The patients were photographed in frontal and incisal regions with a T2i camera (Canon, Japan) with 100 mm macro lens, 35 mm focal length, aperture f22, 1/100 shutter speed and ISO 200. Three randomly selected sites of each patient were used for evaluations and the irradiation values were assessed in the IMAGEJ software (NIH, Wayne Rasband, USA). Intensity in pixels was quantified in relation to the distance from the light incident point. Data were normalized and the results were presented as relative light intensity as a function of distance. The results demonstrated that red laser light is exponentially attenuated as a function of lateral distance and loses approximately 50 % of its intensity by 2.23 mm. On the other hand, the light travels 3 mm in depth to decay 50 %. In conclusion, our data suggest that melanin presence decreases optical pathway and irradiation protocols for antimicrobial photodynamic therapy in gingival tissue should consider light attenuation and depth of periodontal pockets so that efficient illumination of the target tissue occurs. Periodontal pockets bigger than 6 mm should be irradiated with more than one point.

Developing a Tooth in situ Organ Culture Model for Dental and Periodontal Regeneration Research

In this study we have realized the need for an organ culture tooth in situ model to simulate the tooth structure especially the tooth attachment apparatus. The importance of such a model is to open avenues for investigating regeneration of the complex tooth and tooth attachment tissues and to reduce the need for experimental animals in investigating dental materials and treatments in the future. The aim of this study was to develop a porcine tooth in situ organ culture model and a novel bioreactor suitable for future studies of periodontal regeneration, including application of appropriate physiological loading. The Objectives of this study was to establish tissue viability, maintenance of tissue structure, and model sterility after 1 and 4 days of culture. To model diffusion characteristics within the organ culture system and design and develop a bioreactor that allows tooth loading and simulation of the chewing cycle. Methods: Twenty-one porcine first molars were dissected aseptically in situ within their bony sockets. Twelve were used to optimize sterility and determine tissue viability. The remainder were used in a 4-day organ culture study in basal medium. Sterility was determined for medium samples and swabs taken from all tissue components, using standard aerobic and anaerobic microbiological cultures. Tissue viability was determined at days 1 and 4 using an XTT assay and Glucose consumption assays. Maintenance of structure was confirmed using histology and histomorphometric analysis. Diffusion characteristics were investigated using micro-CT combined with finite element modeling. A suitable bioreactor was designed to permit longer term culture with application of mechanical loading to the tooth in situ. Result: XTT and Glucose consumption assays confirmed viability throughout the culture period for all tissues investigated. Histological and histomorphometric analysis confirmed maintenance of tissue structure. Clear microbiological cultures indicated maintenance of sterility within the organ culture system. The novel bioreactor showed no evidence of medium contamination after 4 days of culture. Finite element modeling indicated nutrient availability to the periodontium. Conclusion: A whole tooth in situ organ culture system was successfully maintained over 4 days in vitro.

Facilitation of Bone Healing Processes Based on the Developmental Function of Meox2 in Tooth Loss Lesion

In the present study, we examined the bone healing capacity of Meox2, a homeobox gene that plays essential roles in the differentiation of a range of developing tissues, and identified its putative function in palatogenesis. We applied the knocking down of Meox2 in human periodontal ligament fibroblasts to examine the osteogenic potential of Meox2. Additionally, we applied in vivo periodontitis induced experiment to reveal the possible application of Meox2 knockdown for 1 and 2 weeks in bone healing processes. We examined the detailed histomorphological changes using Masson’s trichrome staining and micro-computed tomography evaluation. Moreover, we observed the localization patterns of various signaling molecules, including α-SMA, CK14, IL-1β, and MPO to examine the altered bone healing processes. Furthermore, we investigated the process of bone formation using immunohistochemistry of Osteocalcin and Runx2. On the basis of the results, we suggest that the knocking down of Meox2 via the activation of osteoblast and modulation of inflammation would be a plausible answer for bone regeneration as a gene therapy. Additionally, we propose that the purpose-dependent selection and application of developmental regulation genes are important for the functional regeneration of specific tissues and organs, where the pathological condition of tooth loss lesion would be.

Perillyl alcohol has antibacterial effects and reduces ROS production in macrophages

Natural products have emerged as a rich source of bioactive compounds for adjunctive treatments of many infectious and inflammatory conditions, including periodontitis. Among the monoterpenes with significant biological properties, there is the perillyl alcohol (POH), which can be found in several essential oils and has shown immunomodulatory properties in recent studies, which may be interesting in the treatment of non-neoplastic inflammatory disorders.

Effects of enamel matrix derivative on clinical and inflammatory outcomes in periodontal maintenance patients: Randomized controlled clinical trial

BACKGROUND

Efficient methods to treat persistent pockets during periodontal maintenance therapy (PMT) require further investigation. The hypothesis of this randomized controlled clinical trial was that local application of enamel matrix derivative (EMD) added to papilla reflection/root preparation (PR/RP) could enhance clinical and inflammatory outcomes, primarily clinical attachment level (CAL).

METHODS

Fifty PMT patients with generalized stage III-IV, grade B periodontitis presenting with a 6- to 9-mm interproximal PD were randomly allocated to (PR/RP+EMD; n = 24) and control (PR/RP+saline; n = 26) therapies by sex and smoking status. Roots were treated with reflection of interproximal papillae, root planing assisted with endoscope evaluation, and acid etching, followed by EMD or saline application. Probing depth (PD), CAL, plaque index (PI), and interproximal bone height were evaluated at baseline and 12-months post-therapy. Gingival crevicular fluid, bleeding on probing (BOP), and interleukin-1β were tested (ELISA) at baseline, 2 weeks, and 6 and 12 months. Groups were compared over time and between groups with Wilcoxon Rank Sum and t-tests.

RESULTS

Both PR/RP+ EMD and PR/RP+S resulted in significant improvements in clinical outcomes (PD and CAL, BOP) from baseline to 12 months. No significant differences were found in clinical or inflammatory outcomes between the experimental and control groups.

CONCLUSIONS

The addition of EMD to PR/RP does not significantly improve clinical or inflammatory outcomes compared with PR/RP alone during periodontal maintenance therapy.

Identification of Interleukin-8-Reducing Lead Compounds Based on SAR Studies on Dihydrochalcone-Related Compounds in Human Gingival Fibroblasts (HGF-1 cells) In Vitro

Background: In order to identify potential activities against periodontal diseases, eighteen dihydrochalcones and structurally related compounds were tested in an established biological in vitro cell model of periodontal inflammation using human gingival fibroblasts (HGF-1 cells). Methods: Subsequently to co-incubation of HGF-1 cells with a bacterial endotoxin (Porphyromonas gingivalis lipopolysaccharide, pgLPS) and each individual dihydrochalcone in a concentration range of 1 µM to 100 µM, gene expression of interleukin-8 (IL-8) was determined by qPCR and cellular interleukin-8 (IL-8) release by ELISA. Results: Structure–activity analysis based on the dihydrochalcone backbone and various substitution patterns at its aromatic ring revealed moieties 2′,4,4′,6′-tetrahydroxy 3-methoxydihydrochalcone (7) to be the most effective anti-inflammatory compound, reducing the pgLPS-induced IL-8 release concentration between 1 µM and 100 µM up to 94%. In general, a 2,4,6-trihydroxy substitution at the A-ring and concomitant vanilloyl (4-hydroxy-3-methoxy) pattern at the B-ring revealed to be preferable for IL-8 release inhibition. Furthermore, the introduction of an electronegative atom in the A,B-linker chain led to an increased anti-inflammatory activity, shown by the potency of 4-hydroxybenzoic acid N-vanillylamide (13). Conclusions: Our data may be feasible to be used for further lead structure designs for the development of potent anti-inflammatory additives in oral care products.

Influence of Periodontal Disease on cardiovascular markers in Diabetes Mellitus patients

The objective of the present study was to establish if individuals with Diabetes Mellitus (DM2) and periodontal diseases (gingivitis or periodontitis) presented an increase in the concentration of modified LDL (moLDL) and what is the influence of periodontal treatment on the decrease of moLDL particles with consequent improvement in the parameters of DM2. Twenty-four diabetic patients with periodontitis (Group 1) and twenty-four diabetic patients with gingivitis (Group 2) were followed up for a period of 12 months. Group 1 was treated with periodontal debridement, and Group 2 received supra-gingival scaling and prophylaxis. In both groups, periodontal clinical parameters: probing depth (PD), clinical attachment level (CAL), gingival resection (GR), bleeding on probing index (BOP) and plaque index; inflammatory serum markers (glycemia, A1c, total cholesterol, HDL-cholesterol (HDL-c), LDL-cholesterol (LDL-c), triglycerides and hs-CRP) and oxidized LDL (oxLDL) were measured at baseline, t = 6 and t = 12 months after treatment. Solutions of LDL were analyzed using the nonlinear optical Z-Scan and optical absorption techniques. The periodontal clinical parameters showed significant improvement (p < 0.05) in both Group after 12 months. For both groups, total cholesterol, HDL-c, LDL-c, triglycerides and A1c levels did not show significant reductions after periodontal therapy. hs-CRP levels in Group 1 presented a significant reduction after 12 months. The glycemic rate and the oxLDL concentrations did not show significant differences as a function of time. The optical measurements of LDL solutions revealed an improvement of the LDL-c quality in both groups. Periodontal debridement was able to improve periodontal parameters and the quality of LDL-c in diabetic patients but without changes in the oxLDL concentration in both groups. Considering the clinical relevance, the reduction of infectious and inflammatory sites present in the oral cavity through periodontal therapy may help with the control and prevention of hyperglycemia and precursors of cardiovascular diseases.

Prevalence of Periodontitis and its Association with Reduced Pulmonary Function: Results from the Korean National Health and Nutrition Examination Survey

Background and Objectives: The current study was performed to evaluate the prevalence of periodontitis and to examine the association between reduced pulmonary function and periodontitis using Sixth Korea National Health and Nutrition Examination Survey (KNHANES) in 2014. Materials and Methods: A cross-sectional evaluation was conducted to estimate the prevalence of periodontitis and to examine the association between periodontitis and reduced pulmonary function while adjusting for sociodemographic characteristics and current smoking status in survey participants between 40 and 79 years old. The presence of periodontitis was evaluated by community periodontal index defined by the World Health Organization, and the assessments of reduced pulmonary function data were made as "normal," "restrictive impairment," or "obstructive impairment." Results: A total of 4004 survey participants representing 25.4 million Koreans were included in the study. Overall, 41.1% of the study population were determined to have periodontitis, and 22.1% had reduced pulmonary function; 7.9% and 14.2% had restrictive- and obstructive- pulmonary impairments, respectively. Age, male gender, and current smoking status were positive predictors for periodontitis. Insurance coverage by workplace and higher education were protective factors against periodontitis. The association between periodontitis and restrictive impairment (adjusted odds ratio (OR) = 1.059, 95% CI 0.729-1.540) or obstructive impairment (adjusted OR = 1.140, 95% CI 0.849-1.530) was not significant. Conclusions: For Koreans, 40-79 years old, age, smoking status, gender, education, and insurance coverage were significant predictors of periodontitis. The prevalence of periodontitis was not significantly associated with reduced pulmonary function. To better understand the relationship between periodontitis and reduced pulmonary function, well-designed and larger scale epidemiologic studies are needed.