Chronic Periodontitis and RANKL/OPG Ratio in Peri-Implant Mucosae Inflammation

Analysis of risk indicators for implant failure in patients with chronic periodontitis

Dental implant restoration shows an effective method for the rehabilitation of missing teeth. The failure rate of periodontal implants in patients with chronic periodontitis is associated with periodontal flora, inflammation, and long-term periodontal bone resorption caused by chronic periodontitis. However, the therapeutic effects of dental implant restoration on inflammation in patients with chronic periodontitis have not addressed. The purpose of this study is to evaluate the risk indicators for inflammation, bone loss and implant failure in patients with chronic periodontitis. A total of 284 patients with dental implant restoration were recruited and divided into periodontally healthy patients (n = 128) and chronic periodontitis patients (n = 156). Periodontal indices including probing depth (PD), sulcus bleeding index (SBI), plaque index (PLI), gingival bleeding (GIL) and bleeding on probing (BOP) were compared in two groups. Inflammatory cytokines including tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-1 (IL-1), matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9) levels at baseline, 6 and 12 months after surgery, and the implant survival rate at 12 months after surgery, as well as the risk factors associated with failure of dental implant were also assessed. Outcomes demonstrated that patients in the chronic periodontitis group had higher values of periodontal indices than those in the periodontally healthy group. All inflammatory parameters in the chronic periodontitis group were higher than those in the periodontally healthy group and negatively associated with the chronic periodontal index (CPI) in chronic periodontitis patients. Chronic periodontitis patients had higher the prevalence of mucositis and peri-implantitis than patients with healthy periodontium. Implant diameter, length and design was associated with the risk of implant failure for chronic periodontitis patients receiving dental implant. The cumulative implant failure rate and incidence of implant fractures for chronic periodontitis patients at 12 months after surgery were 12.10% and 7.23% (p < 0.05), respectively, while were lower in the heathy periodontitis patients. Location, diameter, implant design, immediate loading and bone defect were risk indicators for bone loss for dental implant patients. The risk factors associated with failure of dental implant was higher in chronic periodontitis patients than patients in the periodontally healthy group (14.25% vs. 4.92%, p < 0.05). In conclusion, data in the current study indicate that inflammation is a risk indicator bone loss, implant fracture and implant failure in patients with chronic periodontitis.

N-acyl homoserine lactones lactonase est816 suppresses biofilm formation and periodontitis in rats mediated by Aggregatibacter actinomycetemcomitans

Aims

The current study aimed to explore the adjuvant therapeutic effect of N-acyl homoserine lactones (AHLs)-lactonase est816 on Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans) biological behaviors and periodontitis progression.

Methods

The inhibitory properties of est816 were detected by live/dead bacterial staining, scanning electron microscope (SEM), crystal-violet staining and reverse-transcription quantitative PCR (RT-qPCR). Biocompatibility of est816 on human gingival fibroblasts (HGFs) and human gingival epithelial cells (HGEs) was evaluated by CCK8 and ELISA. The ligature-induced periodontitis model was established in rats. Micro computed tomography and immunohistochemical and histological staining served to evaluate the effect of est816 on the prevention of periodontitis in vivo.

Results

est816 significantly attenuated biofilm formation, reduced the mRNA expression of cytolethal distending toxin, leukotoxin and poly-N-acetyl glucosamine (PNAG) and downregulated expressions of interleukin-6 and tumor necrosis factor-α with low cell toxicity. In vivo investigations revealed est816 decreased alveolar bone resorption, suppressed matrix metalloproteinase-9 expression and increased osteoprotegerin expression.

Conclusion

est816 inhibited A. actinomycetemcomitans biofilm formation and virulence release, resulting in anti-inflammation and soothing of periodontitis in rats, indicating that est816 could be investigated in further research on periodontal diseases.

The use of mucoadhesive oral patches containing epigallocatechin-3-gallate to treat periodontitis: an in vivo study

Objectives

The application of topical drugs such as mucoadhesive oral patches (MOPs) do not irritate the mucosa and are able to increase the permeability of drugs to oral tissue. Epigallocatechin-3-gallate (EGCG) is an active ingredient that exhibits significant antibacterial and anti-inflammatory effects. The purpose of this study was to analyze the therapeutic potential of a mucoadhesive oral patch containing EGCG (MOP-EGCG) in a model of periodontitis and investigate its effects on the expression of osteoprotegerin (OPG), receptor activator of nuclear factor-kappa Β ligand (RANKL) and receptor activator of nuclear factor-κB (RANK).

Methods

A model of periodontitis was induced in Rattus novergicus used Porphyromonas gingivalis by applying 0.03 ml of bacteria locally with 1 × 10¹⁰ colony-forming units (CFU) seven times at 2-day intervals in the central lower incisors. Periodontitis was then treated with MOP (control), a mucoadhesive oral patch containing doxycycline (MOP-doxy) or MOP-EGCG for 1 h/day for 21 days. On days 3, 5, 7, 14 and 21 after treatment, the central lower incisor was biopsied and analyzed by immunohistochemistry for RANK/RANKL and OPG expression in the gingiva tissue.

Results

MOP-EGCG extract significantly reduced the expression of RANKL and increased the expression of OPG and RANK (p < 0.05) when compared to the MOP-doxy and MOP groups.

Conclusion

MOP-EGCG extract reduced the expression of RANKL and increased the expression of OPG and RANK, thus suggesting that MOP-EGCG can inhibit the loss of alveolar bone in periodontitis.

Topography-mediated immunomodulation in osseointegration; Ally or Enemy

Osteoimmunology is at full display during endosseous implant osseointegration. Bone formation, maintenance and resorption at the implant surface is a result of bidirectional and dynamic reciprocal communication between the bone and immune cells that extends beyond the well-defined osteoblast-osteoclast signaling. Implant surface topography informs adherent progenitor and immune cell function and their cross-talk to modulate the process of bone accrual. Integrating titanium surface engineering with the principles of immunology is utilized to harness the power of immune system to improve osseointegration in healthy and diseased microenvironments. This review summarizes current information regarding immune cell-titanium implant surface interactions and places these events in the context of surface-mediated immunomodulation and bone regeneration. A mechanistic approach is directed in demonstrating the central role of osteoimmunology in the process of osseointegration and exploring how regulation of immune cell function at the implant-bone interface may be used in future control of clinical therapies. The process of peri-implant bone loss is also informed by immunomodulation at the implant surface. How surface topography is exploited to prevent osteoclastogenesis is considered herein with respect to peri-implant inflammation, osteoclastic precursor-surface interactions, and the upstream/downstream effects of surface topography on immune and progenitor cell function.

Effect of inflammation on bones in diabetic patients with periodontitis via RANKL/OPG system-A review

Purpose

Diabetes mellitus and periodontitis are inflammatory diseases, the severity of inflammation results in the progression and persistence of both the disorders and affects bones. Diabetic complications aggravate in diabetic subjects having periodontitis; similarly, diabetic patients are more prone to developing gingivitis and periodontitis. Periodontal and diabetic inflammation disturbs bone homeostasis, which possibly involves both innate and adaptive immune responses. The pathogenic processes that link the two diseases are the focus of much research and it is likely that upregulated inflammation arising from each condition adversely affects the other. RANKL/OPG pathway plays a prominent role in periodontal and diabetic inflammation and bone resorption.

Method

This review article summarises the literature on the link between inflammatory cytokines and the prevalence of disturbed bone homeostasis in diabetic patients with periodontitis. An extensive search was done in PubMed, Scopus, Medline and Google Scholar databases between April 2003 and May 2021.

Result

A total of 27 articles, including pilot studies, case-control studies, cross-sectional studies, cohort studies, randomized control trials, longitudinal studies, descriptive studies and experimental studies, were included in our literature review.

Conclusion

Since RANKL/OPG are cytokines and have immune responses, regulating these cytokines expression will help control diabetes, periodontitis and bone homeostasis. The growing evidence of bone loss and increased fracture risk in diabetic patients with periodontitis makes it imperative that health professionals carry out planned treatment focusing on monitoring oral health in diabetic patients; bone markers should also be evaluated in patients with chronic periodontitis with an impaired glycemic state.

Association Between Serum Selenium Concentration and OPG/RANKL/RANK Axis in Patients with Arterial Hypertension

The aim of the study was to determine the relationship between the serum selenium concentration (Se-S) and the blood concentrations of osteoprotegerin (OPG), receptor activator of nuclear factor kappa-Β ligand (RANKL) and the OPG/RANKL ratio in patients with arterial hypertension. The study group comprised 138 patients with arterial hypertension (age: 56.04 ± 11.59 years). Se-S was determined in all the subjects. Based on the Se-S, the following subgroups were distinguished: a subgroup of patients with a lower Se-S ("low-Se", Se-S < median) and a subgroup of patients with a higher Se-S ("high-Se", Se-S ≥ median). Moreover, the blood concentrations of the parameters of bone metabolism and extraskeletal calcification were assessed: OPG and RANKL. The OPG/RANKL ratio was calculated. In the "low-Se" subgroup, the RANKL concentration was statistically significantly lower, and the OPG/RANKL ratio was statistically significantly higher than in the patients in the "high-Se" subgroup. The correlation analysis showed the negative linear relationships between Se-S and OPG (r = - 0.25, p < 0.05) and between Se-S and OPG/RANKL (r = - 0.47, p < 0.05). Moreover, Se-S positively correlated with RANKL (r = 0.33, p < 0.05). In regression analysis, higher body mass index (BMI), smoking and lower Se-S were independently associated with a higher OPG/RANKL ratio, while lower BMI, use of diuretics, β-blockers and ACE inhibitors and lower OPG/RANKL ratio with effective blood pressure control. In summary, in the group of patients with arterial hypertension, lower Se-S is associated with an unfavourable prognostic panel of parameters of bone metabolism and extraskeletal calcification. Lower Se-S is an independent risk factor for a higher OPG/RANKL ratio, which is an independent prediction factor of ineffective blood pressure control in patients with hypertension.

The Th17/Treg cell balance: crosstalk among the immune system, bone and microbes in periodontitis

Periodontopathic bacteria constantly stimulate the host, which causes an immune response, leading to host-induced periodontal tissue damage. The complex interaction and imbalance between Th17 and Treg cells may be critical in the pathogenesis of periodontitis. Furthermore, the RANKL/RANK/OPG system plays a significant role in periodontitis bone metabolism, and its relationship with the Th17/Treg cell imbalance may be a bridge between periodontal bone metabolism and the immune system. This article reviews the literature related to the Th17/Treg cell imbalance mediated by pathogenic periodontal microbes, and its mechanism involving RANKL/RANK/OPG in periodontitis bone metabolism, in an effort to provide new ideas for the study of the immunopathological mechanism of periodontitis.

Decrease in leptin mediates rat bone metabolism impairments during high-fat diet-induced catch-up growth by modulating the OPG/RANKL balance

Due to catch-up growth (CUG), there are adverse effects on human health. However, there is little information about its influence on bone metabolism. This study aimed to investigate the effects of leptin on bone metabolism and formation during high-fat diet (HFD)-induced CUG. We randomly divided male Wistar rats (5 weeks old) into four groups: control (CTL), caloric restriction and normal chow (RN), caloric restriction (4 weeks), and HFD (RH), and RH + leptin antagonist (RH + LEPA). We monitored body weights, biochemical markers, and epididymal and perirenal fat in these rats. We then performed Hematoxylin and Eosin (H&E) staining to evaluate bone metabolism. We detected osteoprotegerin (OPG) and receptor activator of nuclear factor-kappa b ligand (RANKL) by qRT-PCR and immunohistochemistry (IHC). We found that HFD increased the body weights in rats. In RN, RH, and RH + LEPA groups, major biochemical markers of bone metabolism in rat serum were significantly altered. We found that epididymal and perirenal fat tissues of RH and RH + LEPA groups were higher than those in the RN group. Severe bone formation impairment in the distal diaphysis and metaphysis of the left femora and lumbar vertebra was seen in the RH group compared to RN, which was even aggravated by a leptin antagonist. OPG in the left femora and lumbar vertebra was lower in RH than the RN group. The leptin antagonist decreased OPG during CUG in the RH group, whereas RANKL expression showed an opposite alteration. During HFD-induced CUG, bone formation was mediated by OPG and RANKL and was affected by the leptin content.

Toll-Like Receptor Signaling and Immune Regulatory Lymphocytes in Periodontal Disease

Periodontitis is known to be initiated by periodontal microbiota derived from biofilm formation. The microbial dysbiotic changes in the biofilm trigger the host immune and inflammatory responses that can be both beneficial for the protection of the host from infection, and detrimental to the host, causing tissue destruction. During this process, recognition of Pathogen-Associated Molecular Patterns (PAMPs) by the host Pattern Recognition Receptors (PRRs) such as Toll-like receptors (TLRs) play an essential role in the host–microbe interaction and the subsequent innate as well as adaptive responses. If persistent, the adverse interaction triggered by the host immune response to the microorganisms associated with periodontal biofilms is a direct cause of periodontal inflammation and bone loss. A large number of T and B lymphocytes are infiltrated in the diseased gingival tissues, which can secrete inflammatory mediators and activate the osteolytic pathways, promoting periodontal inflammation and bone resorption. On the other hand, there is evidence showing that immune regulatory T and B cells are present in the diseased tissue and can be induced for the enhancement of their anti-inflammatory effects. Changes and distribution of the T/B lymphocytes phenotype seem to be a key determinant of the periodontal disease outcome, as the functional activities of these cells not only shape up the overall immune response pattern, but may directly regulate the osteoimmunological balance. Therefore, interventional strategies targeting TLR signaling and immune regulatory T/B cells may be a promising approach to rebalance the immune response and alleviate bone loss in periodontal disease. In this review, we will examine the etiological role of TLR signaling and immune cell osteoclastogenic activity in the pathogenesis of periodontitis. More importantly, the protective effects of immune regulatory lymphocytes, particularly the activation and functional role of IL-10 expressing regulatory B cells, will be discussed.

Contribution of acrB upregulation & OmpC/Ompk36 loss over the presence of blaNDM towards carbapenem resistance development among pathogenic Escherichia coli & Klebsiella spp

Background & objectives:

The global spread of carbapenem-resistant Enterobacteriaceae (CRE) is an emerging clinical problem. Hence, in this study, the plausible role of extended-spectrum beta-lactamases (ESBLs)/carbapenemases, OmpC/Ompk36, acrB and their combinations was explored among CRE.

Methods:

The minimum inhibitory concentration (MIC) of meropenem, enzyme-phenotypes (ESBLs/IR and metallo-beta-lactamase (MBL)/non-MBL carbapenemase), genotypes (bla_TEM,bla_SHV and bla_CTX-M; bla_NDM and bla_VIM;bla_KPC and bla_OXA-48-like variants), acrB and outer membrane protein (OMP) expressions were analyzed with a total of 101 non-duplicate clinical isolates, obtained from various samples of patients visiting two tertiary care units of Eastern India during May 2013 - October 2016. This included Escherichia coli (n=36) and Klebsiella pneumoniae (n=65), categorized into two groups, namely Group I (resistant to all carbapenems; n=93; E. coli=34 and Klebsiella spp.=59) and Group II (non-resistant to all the carbapenems; n=8; E. coli=2 and Klebsiella spp.=6).

Results:

Though 88.17 per cent of Group I isolates exhibited ESBL property, the presence of carbapenemase activity (70.96%) and that of bla_NDM gene (42/66: 63.63%) indicated their contributions towards the emergence of CRE. Further, porin loss and/or efflux pump activation among ESBL/carbapenemase-producing isolates heightened the MIC of meropenem from 64 to 256 mg/l (range exhibited by only ESBL/carbapenemase-producing isolates) to >256 mg/l.

Interpretation & conclusions:

These findings implied the major contribution of porin loss and/or efflux pump activation over the presence of ESBLs/carbapenemases in imparting carbapenem resistance in pathogenic bacteria.

The effect of Phase 1 periodontal treatment on the salivary RANKL/OPG ratio in severe chronic periodontitis

Background

RANKL and OPG play an important role in bone resorption. The R A N K L O P G ratio increases in periodontal disease. The present study was conducted to evaluate the effect of Phase 1 periodontal treatment on the salivary R A N K L O P G ratio in patients with severe chronic periodontitis.

Materials and methods

Saliva samples were collected from 13 patients with severe chronic periodontitis and 14 healthy controls at baseline and then four weeks after the treatment using unstimulated spitting. The salivary levels of RANKL, OPG and R A N K L O P G ratio were investigated using the ELISA method.

Results

The findings of this study showed that the mean R A N K L O P G ratio was significantly higher in the patients with periodontal disease than in the healthy controls (P=0.001). Also, the R A N K L O P G ratio was significantly higher in the patients with a higher mean CAL (P=0/004). The comparison of the salivary R A N K L O P G ratio in patients with periodontal disease before and four weeks after the treatment showed a significant reduction in this value four weeks after the periodontal treatment (P=0/001).

Conclusion

The results of this study showed a direct relationship between the R A N K L O P G ratio and the severity of periodontal disease. Phase 1 of periodontal treatment was found to be effective in reducing the R A N K L O P G ratio. In other words, the R A N K L O P G ratio can be a good predictor of treatment success. Further long-term studies with larger sample sizes are required for confirming these results.

Dental genetics in Brazil: Where we are

Dentistry constitutes the basic nucleus of professionals of higher level of health in Brazil with one of the largest concentrations of dentists per capita in the world. However, the genetic in dentistry in Brazil is explored, basically, in research field. Future actions need to be performed in order to deep the whole knowledge about diagnosis and treatment of diseases with genetic basis in dentistry, in Brazil.