Differences between inflammatory and catabolic mediators of peri-implantitis and periodontitis lesions following initial mechanical therapy: An exploratory study

Etiology, pathogenesis and treatment of peri-implantitis: A European perspective

Peri-implantitis is a plaque-associated pathological condition occurring in tissues around dental implants. It is characterized by inflammation in the peri-implant mucosa and progressive loss of supporting bone. Over the last 30 years, peri-implantitis has become a major disease burden in dentistry. An understanding of the diagnosis, etiology and pathogenesis, epidemiology, and treatment of peri-implantitis must be a central component in undergraduate and postgraduate training programs in dentistry. In view of the strong role of European research in periodontology and implant dentistry, the focus of this review was to address peri-implantitis from a European perspective. One component of the work was to summarize new and reliable data on patients with dental implants to underpin the relevance of peri-implantitis from a population perspective. The nature of the peri-implantitis lesion was evaluated through results presented in preclinical models and evaluations of human biopsy material together with an appraisal of the microbiological characteristics. An overview of strategies and outcomes presented in clinical studies on nonsurgical and surgical treatment of peri-implantitis is discussed with a particular focus on end points of therapy and recommendations presented in the S3 level Clinical Practice Guideline for the prevention and treatment of peri-implant diseases.

Inflammasomes NLRP3 and AIM2 in peri-implantitis: A cross-sectional study

BACKGROUND

Inflammasome components NLRP3 and AIM2 contribute to inflammation development by the activation of caspase-1 and IL-1β. They have not been yet evaluated in samples from patients with active peri-implantitis. Thus, the aim of the present study is to analyze the expression of inflammasomes NLRP3 and AIM2 and subsequent caspase 1 and IL-1β assessing the microenvironment of leukocyte subsets in samples from patients with active peri-implantitis.

METHODS

Biopsies were collected from 33 implants in 21 patients being treated for peri-implantitis. Biopsies from gingival tissues from 15 patients with healthy periodontium were also collected for control. These tissues were evaluated through conventional histological stainings. Then, immunohistochemical detection was performed to analyze NLRP3, AIM2, caspase-1, and IL-1β and markers of different leukocyte subsets. PCR for inflammasomes and related genes was also done.

RESULTS

This manuscript reveals a high immunohistochemical and mRNA expression of NLRP3 and AIM2 inflammasomes, caspase-1, and IL-1β in biopsies collected from human peri-implantitis. The expression of the tested markers was significantly correlated with the increase in inflammatory infiltrate, probing depth, presence of biofilm, and bleeding on probing. In these peri-implantitis lesions, the area of biopsy tissue occupied by inflammatory infiltrate was intense while the area occupied by collagen was significantly lower. In comparison with periodontal healthy tissues, the inflammatory infiltrate was statistically significantly higher in the peri-implantitis biopsies and was mainly composed of plasma cells, followed by T and B lymphocytes.

CONCLUSION

In human peri-implantitis, chronic inflammation can be explained in part by the action of IL-1β/caspase 1 induced through NLRP3 and AIM2 inflammasome activation.

Revealing leukocyte populations in human peri-implantitis and periodontitis using flow cytometry

OBJECTIVE

To identify, quantify, and characterize leukocyte populations in PI and periodontitis using flow cytometry.

METHODS

Fresh biopsies from human PI and periodontitis lesions were processed to a single-cell suspension. The immune cell types were identified using flow cytometry.

RESULTS

Twenty-one biopsies were obtained and analyzed corresponding to fourteen PI and seven periodontitis samples. Participants' average age was 63.95 ± 14.77 years without a significant difference between PI and periodontitis patients, the female/male ratio was 8/12, and mean PD was 8.5 ± 2.17. High similarity was found between periodontitis and PI in the main immune cell types. Out of the leukocytes, the PMN proportion was 40% in PI and 33% in periodontitis. T-cells 22% in PI and 18% in periodontitis. Similar proportions of B-cells 10% and macrophages 6% were found in PI and periodontitis. Dendritic and NK cells were found in low proportions (~ 1%) in PI and periodontitis. T-cell sub-analysis showed that CD4-positive were more prevalent than CD8-positive in both diseases (CD4/CD8 ratio of 1.2).

CONCLUSION

With the use of flow cytometry analysis, the leukocyte populations in human peri-implantitis and periodontitis were classified. In PI and periodontitis, we identified similar proportions of specific (CD4/CD8) and innate (dendritic and NK) immune cells. These results corroborate previous histological studies.

CLINICAL RELEVANCE

Flow cytometry analysis can be used to identify and quantify immune cells in PI and periodontitis, including sub-classification of T cells (CD4/8) as well as detection of cells that require multiple markers for identification (such as dendritic cells).

Early diagnosis for the onset of peri-implantitis based on artificial neural network

The aim of this study is to construct an artificial neural network (ANN) based on bioinformatic analysis to enable early diagnosis of peri-implantitis (PI). PI-related datasets were retrieved from the Gene Expression Omnibus database. Differentially expressed genes (DEGs) and functional enrichment analyses were performed between PI and the control group. Furthermore, the infiltration of 22 immune cells in PI was analyzed using CIBERSORT. Hub genes were identified with random forest (RF) classification. The ANN model was then constructed for early diagnosis of PI. A total of 1,380 DEGs were identified. Enrichment analysis revealed the involvement of neutrophil-mediated immunity and the NF-kappa B signaling pathway in PI. Additionally, higher proportion of naive B cells, activated memory CD4 T cells, activated NK cells, M0 macrophages, M1 macrophages, and neutrophils were observed in the soft tissues surrounding PI. From the RF analysis, 13 hub genes (ST6GALNAC4, MTMR11, SKAP2, AKR1B1, PTGS2, CHP2, CPEB2, SYT17, GRIP1, IL10, RAB8B, ABHD5, and IGSF6) were selected. Subsequently, the ANN model for early diagnosis of PI was constructed with high performance. We identified 13 hub genes and developed an ANN model that accurately enables early diagnosis of PI.

Pro- and anti-inflammatory cytokines and osteoclastogenesis-related factors in peri-implant diseases: systematic review and meta-analysis

BACKGROUND

Pro- and anti-inflammatory cytokines are acknowledged, during inflammatory bone destruction, as key regulators of osteoclast and osteoblast differentiation and activity. However, evidence regarding the exact role of pro- and anti-inflammatory cytokines and osteoclastogenesis-related factors in peri-implant diseases is unclear. We aimed to execute a systematic review and meta-analysis about the pro- and anti-inflammatory cytokines and osteoclastogenesis-related factors levels in peri-implant diseases.

METHODS

The focused question was elaborated to summarize the levels of pro-and anti-inflammatory cytokines and osteoclastogenesis-related factors in tissue samples (mRNA) and biofluids (protein levels) of patients with/without peri-implant diseases. Electronic searches of the PubMed, Cochrane Controlled Trials Registry, Web of Science, EMBASE, Scopus and Google scholar databases were conducted for publications up to March 2023. Meta-analysis evaluating the mediator´s levels (protein levels by ELISA) in peri-implant crevicular fluid (PICF) were made. The effect size was estimated and reported as the mean difference. The 95% confidence interval was estimated for each mediator, and the pooled effect was determined significant if two-sided p-values < 0.05 were obtained.

RESULTS

Twenty-two publications were included in the systematic review (qualitative analysis), with nine of these subjected to meta-analyses (quantitative analysis). In the qualitative analysis, higher pro-inflammatory cytokines [Interleukin (IL)-1β, IL-6] and pro-osteoclastogenic mediator [Receptor Activator of Nuclear Factor-Kappa B ligand (RANKL)] levels were observed in PICF of individuals with peri-implant diseases in comparison to healthy individuals. Higher RANKL/osteoprotegerin (OPG) ratios were observed in PICF from individuals with peri-implant diseases in comparison to healthy individuals. Meta-analysis showed higher RANKL levels in diseased groups compared to controls.

CONCLUSIONS

The results showed that the levels of IL-1β, IL-6, IL-10, and RANKL/OPG are not balanced in peri-implant disease, suggesting that these mediators are involved in the host osteo-immunoinflammatory response related to peri-implantitis.

Peri-implantitis after 40 years: Evidence, mechanisms, and implications: A mapping review

STATEMENT OF PROBLEM

The high prevalence of peri-implantitis (PI) continues to plague patients and the disease is resistant to present treatment regimens. An analysis of the available research is lacking.

PURPOSE

Given the abundance and diversity of research on the topic of PI, the purpose of this mapping review was to synthesize the literature on the prevention of PI, the histopathology of the disease, the state of present therapeutics, and any emerging treatments.

MATERIAL AND METHODS

An extensive literature search was undertaken by using the electronic databases of PubMed, Web of Science, and Science Direct. The keyword strings were peri-implantitis, dental implant, risk assessment, histopathology, prosthesis design, and treatment. The filters applied were time interval from 2000 to 2002; language, English.

RESULTS

A total of 3635 articles were taken from PubMed, 3686 articles from Web of Science, and 2450 articles from Science Direct. After applying the inclusion and exclusion criteria to the titles and abstracts of selected investigations, 214 studies were retrieved.

CONCLUSIONS

The evidence reflects a concerning incidence of PI, without a predictable treatment protocol. An in-depth patient risk assessment considering risk modification, emphasis on surgical and restorative expertise, and strict recall and maintenance is essential to minimize PI.

Histopathological characterization of peri-implant diseases: A systematic review and meta-analysis

OBJECTIVE

To conduct a systematic review of the inflammatory elements in peri-implantitis (PI) and peri-implant mucositis (PM) in comparison with healthy peri-implant tissues (HI) and periodontal disease.

DESIGN

The PubMed, Embase, Web of Science, and Scopus databases were searched up to December 2020. English articles that evaluated human soft tissue biopsies of PI or PM were included. Values reported for the surface area of the infiltrated connective tissue (ICT) were pooled using the random-effect model meta-analysis to estimate the mean (95% CI).

RESULTS

A total of 33 articles were included. Of 30 studies on PI, the majority evidenced significantly increased vascularization and inflammatory cell counts dominated by plasma cells in PI compared with HI. Studies that compared PI with chronic periodontitis primarily reported more severe inflammatory infiltrates in PI. This was confirmed by the meta-analysis results since the surface area of the ICT was significantly larger in PI (p < 0.001). Only seven studies analyzed the PM lesions and reported increased inflammatory infiltrates and vascularization in PM compared with HI. Based on the meta-analysis results, the surface area of the ICT was 3.00 [1.50, 4.51] mm ² in PI and 0.23 [0.02, 0.44] mm ² in PM lesions. Based on the available evidence, presence of foreign body particles considerably increased the inflammatory infiltrate; however, smoking did not have a significant effect.

CONCLUSIONS

There was controversy regarding the prevalence of various inflammatory cell types in peri-implant diseases; however, a considerably high ICT surface area in PI indicates the aggressive nature of the disease.

Erbium, chromium-doped: yttrium, scandium, gallium, garnet and diode lasers in the treatment of peri-implantitis: clinical and biochemical outcomes in a randomized-controlled clinical trial

This study aims to evaluate the effects of 940 nm diode laser and 2780 nm erbium, chromium-doped: yttrium, scandium, gallium, garnet (Er,Cr:YSGG) laser used in addition to mechanical therapy in the non-surgical treatment of peri-implantitis on clinical parameters and matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinase-1 (TIMP-1) levels in the peri-implant crevicular fluid. A total of 50 patients with peri-implantitis were randomized into three groups to receive peri-implant treatment. The control group (n = 17) only received conventional non-surgical mechanical therapy. The trial groups [(diode group (n = 16) and Er,Cr:YSGG group (n = 17)] received dental laser in addition to mechanical therapy. Gingival index (GI), plaque index (PI), bleeding on probing, probing depth (PD), MMP-9, and TIMP-1 levels were assessed at baseline (T0) and at 6 months after treatment (T1). The GI, PI, and PD significantly decreased in all groups at T1, compared to T0 (p < 0.05). The decrease in the PD was similar between the control and diode groups with Er,Cr:YSGG providing more reduction (1.16 ± 0.64 mm) than either method (p = 0.032). A significant intra-group decrease in MMP-9 level was only observed in the Er,Cr:YSGG group (p = 0.009). The decrease in TIMP-1 level from T0 to T1 was similar between the control and the diode groups (p > 0.05) and it was significantly lower than the decrease in the Er,Cr:YSGG group (p < 0.05). Addition of diode laser to non-surgical mechanical therapy does not provide any additional benefit for treatment outcomes. The Er,Cr:YSGG laser seems to be more efficient both at clinical and molecular levels. ClinicalTrials, ID: NCT04730687. Registered 13 April 2021. Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT04730687.

Association of IL-10 and TNF-α Polymorphisms with Dental Peri-Implant Disease Risk: A Meta-Analysis, Meta-Regression, and Trial Sequential Analysis

Genetic susceptibility has been reported to be an important risk factor for peri-implant disease (PID). The aim of this meta-analysis was to assess the association between TNF-α and IL-10 polymorphisms and PID susceptibility. The Web of Science, Cochrane Library, Scopus, and PubMed/Medline databases were searched for studies published until 12 April 2021. RevMan 5.3, CMA 2.0, SPSS 22.0, and trial sequential analysis software were used. Twelve studies were included in our analysis. The pooled ORs for the association of TNF-α (−308 G > A), IL-10 (−1082 A > G), IL-10 (−819 C > T), and IL-10 (−592 A > C) polymorphisms were 1.12, 0.93, 1.35, and 0.77 for allelic; 1.42, 0.95, 3.41, and 0.34 for homozygous; 1.19, 1.88, 1.23, and 0.49 for heterozygous, 1.53, 1.12, 1.41, and 0.39 for recessive; and 1.16, 1.87, 2.65, and 0.75 for dominant models, respectively, with all the estimates being insignificant. The results showed an association between TNF-α (−308 G > A) polymorphism and the risk of PID in patients of Asian ethnicity (OR = 1.59; p = 0.03). The present meta-analysis illustrated that TNF-α (−308 G > A), IL-10 (−1082 A > G), IL-10 (−819 C > T), and IL-10 (−592 A > C) polymorphisms were not associated with the risk of PID, whereas TNF-α (−308 G > A) polymorphism was associated with an elevated risk of PID in Asian patients.

Biomarkers associated with periodontitis and peri-implantitis: a systematic review

Purpose

The pathology of peri-implantitis is still not fully understood and there have been recent challenges to the consensus on its aetiology and pathology, especially in comparison with periodontitis. The assessment of biomarkers allows a comparison of the pathology of these diseases. The aim of this systematic review was to answer the research question: “Is there a difference in the biomarkers associated with peri-implantitis compared with periodontitis in adult humans?”

Methods

Electronic databases were searched and screened, and a manual search was also undertaken. The inclusion criteria were adults with peri-implantitis who had been compared to adults with periodontitis with the outcome of biomarkers assessed via biopsies or crevicular fluid samples in primary or secondary care settings, as recorded in case-control, case series and retrospective, prospective and cross-sectional observational studies. Two reviewers independently screened titles and abstracts and assessed full text articles for eligibility and inclusion. Both reviewers independently extracted data and assessed risk of bias. Differences in biomarker levels were the primary outcome and a narrative review was undertaken due to the heterogeneity of studies.

Results

In total, 2,374 articles were identified in the search, of which 111 full-text articles were assessed for eligibility and 13 were included in the qualitative synthesis. Five of the 13 included studies were deemed to be at high risk of bias, with the others having moderate risk. All studies were cross-sectional and performed at university hospitals. Nine of the 13 included studies found significant differences in the levels of biomarkers or their ratios between peri-implantitis and periodontitis. Four of the studies found no significant differences.

Conclusions

Within the limitations of the included studies, it appears that there may be a difference in biomarker levels and ratios between peri-implantitis and periodontitis, suggesting that these disease processes are somewhat distinct.

Induced Experimental Periimplantitis and Periodontitis: What are the Differences in the Inflammatory Response ?

This preliminary study investigates the differences between experimental periodontitis and periimplantitis in a dog model, with a focus on the histopathology, the inflammatory responses and specific immunoregulatory activities, driven by Th1/Th2 positive cells. Twelve dental implants were inserted into the edentulated posterior mandibles of six Beagle dogs and were given twelve weeks time for osseointegration. Experimental periimplantitis and periodontitis (first mandible molar) was then induced using cotton-floss ligatures. Twelve weeks later, alveolar bones were quantitated by cone beam-computer tomography. Histopathological analysis of the inflamed gingiva and of the periodontal tissues was performed by light microscopy, and the Th1/ Th2 cell populations were investigated by flow cytometry. Periimplantitis as well as periodontitis were both found to be associated with pronounced bone resorption effects, both to a similar degree vertically, but with a differential bone resorption pattern mesio-distally, and with a significantly higher and consistent bone resorption result in periimplantitis; however, with a higher variance of bone resorption in periodontitis. The histological appearances of the inflammatory tissues were identical. The percentages of Th1/ Th2 cells in the inflamed gingival tissues of both experimental periimplantitis and periodontitis were also found to be similar. Experimental periodontitis and periimplantitis in the dog model show essentially the same cellular pathology of inflammation. However, bone resorption was found to be significantly higher in periimplantitis; the histopathological changes in the periodontal tissues were similar in both groups, but showed a higher inter-individual variation in periodontitis, and appeared more uniform in periimplantitis. This preliminary study indicates that more focused experimental in-vivo inflammation models need to be developed to better simulate the human pathology in the two different diseases, and in order to have a valuable tool to investigate more specifically how novel treatments/prevention approaches may heal the differential adverse effects on bone tissue and on periodontium in periodontitis and in periimplantitis.

Cellular expression of DNA damage/repair and reactive oxygen/nitrogen species in human periodontitis and peri-implantitis lesions

AIM OF THE STUDY

To evaluate differences in the cellular expression of DNA damage/repair and reactive oxygen/nitrogen species between human periodontitis and peri-implantitis lesions.

MATERIAL AND METHODS

40 patients presenting with generalized severe periodontitis and 40 patients with severe peri-implantitis were included. Soft tissue biopsies were collected from diseased sites in conjunction with surgical therapy and prepared for histological analysis. Four regions of interest were identified: the pocket epithelium (PE), the infiltrated connective tissue (ICT), which was divided into one inner area facing the PE (ICT-1) and one outer area (ICT-2). A non-infiltrated connective tissue area (NCT) lateral of the ICT was also selected.

RESULTS

It was demonstrated that the ICT of peri-implantitis specimens was considerably larger and contained significantly larger area proportions and densities of CD68-, MPO- and iNOS-positive cells than that of periodontitis samples. Cellular densities were overall higher in the inner ICT zone lateral of the PE (ICT-1) than in the outer ICT compartment (ICT-2). While the NCT area lateral of the ICT comprised significantly larger proportions and densities of y-H2AX-, iNOS-, NOX2-, MPO- and PAD4/MPO-positive cells in peri-implantitis than in periodontitis sites, a reverse difference was noted for the area proportion and density of 8-OHdG-positive cells in the PE.

CONCLUSIONS

It is suggested that peri-implantitis lesions are associated with an enhanced and upregulated host response and contain larger numbers of neutrophils, macrophages and iNOS-positive cells than periodontitis lesions.

Validity of fractal analysis of implants in individuals with healthy and diseased peri-implant mucosa

OBJECTIVE

The purpose of this study was to determine whether fractal analysis could discriminate the peri-implant trabecular bone between individuals with healthy peri-implant mucosa and peri-implant disease using digital periapical radiographs.

MATERIAL AND METHODS

The electronic health records of patients with a dental implant were reviewed to determine their eligibility. One hundred four patients (aged 27-89 years) were included and divided into three groups. Group 1) Individuals with healthy peri-implant mucosa; Group 2) Individuals with peri-implant mucositis; or Group 3) Individuals with peri-implantitis. The following clinical measurements for each dental implant were extracted: probing depth (PD), clinical attachment level (CAL), and the presence or absence of bleeding on probing (BOP). Digital periapical images of the implant were used to calculate the fractal dimension (FD) for each implant at two regions of interest (ROI). Summary statistics were calculated for mean PD, mean CAL, mean percent BOP, and mean FD by group. Differences among groups were tested using one-way analysis of variance (ANOVA). Spearman nonparametric correlations were tabulated for mean PD, mean CAL, mean percent BOP, and mean FD.

RESULTS

The only measure that did not demonstrate significant differences among groups was FD (p = .559) with all other measures demonstrating a significant difference (p < .001).

CONCLUSIONS

Based on this study, FD of the peri-implant bone calculated from a periapical radiograph does not appear to be a valid method to distinguish between healthy and diseased implants, while clinical measures of PD, CAL, and BOP are useful for the diagnosis of peri-implant health, peri-implant mucositis, and peri-implantitis.

Morphological and Molecular-Biological Features of Inflammatory and Regeneratory Processes in Peridont Tissues with Periimplantitis and Periodontitis

A morphological and immunohistochemical study of periodontal tissues was performed in patients with chronic generalized periodontitis who underwent dental implantation. We studied 44 biopsy specimens from 21 patients (13 women and 8 men) aged 35-60 years with a diagnosis of periimplantation mucositis (7 patients), periimplantitis (8 patients), and severe chronic generalized periodontitis (6 patients). It was established that periimplantitis differs from periimplantation mucositis by a more pronounced inflammatory reaction with a clear predominance of plasma cells in the infiltrate, which captures the fibrous capsule around the implant, destroys it and further spreads to the bone tissue. Based on the immunohistochemical differences in SMA, VEGF, and Ki-67, it is concluded that periimplantation mucositis and periimplantitis are successive stages of progression of the same process. When comparing chronic generalized periodontitis and periimplantitis, the latter shows much more pronounced inflammatory and destructive processes in the area of the implant, due to the addition of immune inflammation, impaired regeneration processes, and destruction of bone tissue.

Histological evaluation of peri-implant mucosal and gingival tissues in peri-implantitis, peri-implant mucositis and periodontitis patients: a cross-sectional clinical study

Objective: Aim of present study was to evaluate gingival tissue samples obtained from healthy and diseased sites of teeth and dental implants in terms of hypoxia and collagenase activity.Methods: Four study groups were created as Group-1; healthy individuals (H), Group-2; periodontitis patients with stage 3 grade B (P), Group-3; patients with peri-implant mucositis. Group-4; patients with peri-implantitis (P-IMP). Plaque index (PI), gingival index (GI) and probing pocket depth (PPD) were recorded. Gingival and peri-implant mucosal biopsies were obtained. Fibroblast and inflammatory cells were counted. Hypoxia-inducible factor (HIF)-1α, prolyl hydroxylase (PH), matrix metalloproteinase (MMP)-8, tissue inhibitor of MMPs (TIMP)-1, cyclooxygenase (COX)-2 and inducible nitric oxide synthase (iNOS) levels were determined via immunohistochemistry.Results: Healthy controls had highest fibroblast cell counts and lowest inflammatory cell counts compared to other groups. Peri-implantitis and periodontitis samples had similar fibroblast and inflammatory cell counts, while peri-implant mucositis had higher fibroblast cells and lowered inflammatory cells compared to periodontitis and peri-implantitis samples. HIF-1α, COX-2 and iNOS levels were lowest in healthy controls and increased in other groups. Peri-implant mucositis samples had significantly lower expressions of HIF-1α, COX-2 and iNOS compared to peri-implantitis and periodontitis groups. PH expressions were lower in periodontitis and peri-implantitis groups compared to healthy controls and peri-implant mucositis groups. MMP-8 levels were lower in healthy group compared to other groups while levels were similar in periodontitis, peri-implant mucositis and peri-implantitis groups. TIMP levels were similar in groups.Conclusion: Periodontitis, peri-implantitis, and peri-implant mucositis samples exhibited higher inflammation and lower fibroblast cell counts and tend to have increased tissue collagenase activity, hypoxia and inflammation compared to healthy samples.

Impact of periodontal treatment on the RANKL/OPG ratio in crevicular fluid

Aim

Alveolar resorption is one of the most important events in periodontitis. Osteoclast activity is regulated by the ratio between receptor activator of NF-κB ligand (RANKL) and osteoprotegerin (OPG). The aim of this study was to evaluate changes in the RANKL/OPG ratio in crevicular fluid after periodontal treatment.

Material and methods

A total of 15 patients with periodontitis were included in the study group. Samples were collected from an area with active periodontitis and a healthy area. The RANKL and OPG levels were measured before and after periodontal scaling and root planing (SRP) treatment. The study group was compared to the control group, which included 10 patients without periodontitis. ID Clinicaltrial.gov: NCT03787875.

Results

A decrease in the RANKL level was found in areas with active periodontitis after periodontal treatment, but no change in the OPG level was observed.

Therefore, the treatment induced a decrease in the RANKL/OPG ratio in sites with destructive periodontal activity.

Conclusions

Periodontal treatment acts on the RANKL/OPG ratio by decreasing osteoclastogenesis. These results encourage the use of these molecules for periodontal diagnosis, monitoring and treatment.

ID Clinicaltrial.gov

NCT03787875.

Long non-coding RNA and mRNA expression profiles in peri-implantitis vs periodontitis

BACKGROUND AND OBJECTIVE

Peri-implantitis is a biofilm-mediated infectious disease that results in progressive loss of implant-supporting bone. As compared to its analogue periodontitis, peri-implantitis is generally known to be more aggressive, with comparatively rapid progression and less predictable treatment outcomes, especially when advanced. An understanding of molecular mechanisms underpinning the similarities and differences between peri-implantitis and periodontitis is essential to develop novel management strategies. This study aimed to compare long non-coding RNAs (lncRNAs) and messenger RNA (mRNA) expression profiles between peri-implantitis and periodontitis.

METHODS

Inflamed soft tissue from peri-implantitis and periodontitis lesions, and healthy gingival tissue controls were analyzed by microarray. Cluster graphs, gene ontology (GO) analysis, and pathway analysis were performed. Quantitative real-time PCR was employed to verify microarray results. The expression levels of RANKL and OPG in the three tissue types were also evaluated, using qRT-PCR. Coding non-coding (CNC) network analyses were performed.

RESULTS

Microarray analyses revealed 1079 lncRNAs and 1003 mRNAs as differentially expressed in peri-implantitis when compared to periodontitis. The cyclooxygenase-2 pathway was the most up-regulated biological process in peri-implantitis as compared to periodontitis, whereas hemidesmosome assembly was the most down-regulated pathway. Osteoclast differentiation was relatively up-regulated, and RANKL/OPG ratio was higher in peri-implantitis than in periodontitis.

CONCLUSIONS

The study demonstrated that peri-implantitis and periodontitis exhibit significantly different lncRNA and mRNA expression profiles, suggesting that osteoclast differentiation-related pathways are comparatively more active in peri-implantitis. These data highlight potential molecular targets for periodontitis and peri-implantitis therapy development.

Interleukin - 17 and Interleukin-10 as Inflammatory and Prevention Biomarkers in Periimplant Diseases

Background

Periimplant diseases are inflammatory diseases. Thus, the level of preinflammatory cytokines which has important role in the inflammation processes can consider as biomchemical markers for early diagnosis and prevention of periimplant diseases. The aim of this study was to determine and compare the level of interleukin (IL)-17 and IL-10 in patients with periimplant mucositis and periimplantitis.

Methods

This case--control study was conducted on 51 patients with implants which were loaded at least 1 year previously, 17 patients with periimplant mucositis, 17 patients with periimplantitis, and 17 individuals with healthy implants. After clinical examination, gingival crevicular fluid sampling was carried out by paper point number 25 for 4 min and the mean value of IL-17, IL-10 in samples was measured using enzyme linked immunosorbent assay (ELISA), least square differences (LSD) reader in laboratory. The data was analyzed using statistical software SPSS 22. Quantitative analysis was done using One-way analysis of variance (ANOVA) test and LSD past test.

Results

The results of analysis showed that there was a significant difference in the mean value of IL-17 and IL-10 between the three study groups (P < 0.001). Individuals with healthy implants showed a significant lower level of IL-17 than patients with periimplantitis (P = 0.001) and for patients with periimplantitis, the level of IL-17 was significantly lower than that of patients with periimplant mucositis (P < 0.001) and IL-10 level was significantly lower in mucositis than periimplantitis (P < 0.001).

Conclusions

The level of IL-17 and IL-10 increased in patients with periimplant compared to individuals with healthy periimplant tissues and the results showed that the highest concentrations of IL-17 and IL-10 were observed in patients with periimplant mucositis and periimplantitis, respectively.

The relationship between T-helper cell polarization and the RANKL/OPG ratio in gingival tissues from chronic periodontitis patients

This study aimed to investigate the relationship between inflammation‐related T‐helper cell polarization and the receptor activator for nuclear factor‐κB ligand (RANKL)/osteoprotegerin (OPG) ratio, which is associated with bone resorption or remodeling of chronic periodontitis patients. Gingival crevicular fluid (GCF) and gingival tissues were obtained from periodontally healthy individuals (PH group) and chronic periodontitis patients (CP group). The GCF levels of IFN‐γ, IL‐4, IL‐17, and IL‐10 linked to T‐helper cell polarization toward the Th1, Th2, Th17, and Treg phenotypes, respectively, were determined by ELISA. The expression levels of these cytokines and the polarized T‐helper cells in gingival tissues were assessed through immunohistochemical and immunofluorescence assays. In addition, the RANKL and OPG expression levels in gingival tissues were detected by immunohistochemical assays, and linear regression analysis was used to identify the potential relationship between T‐helper cell polarization and the RANKL/OPG ratio. In total, 22 individuals and 35 patients were enrolled in the present study. In both GCF and gingival tissues, increased levels of IL‐17 and the decreased levels of IL‐4 and IL‐10 were observed in the CP group. When polarized T‐helper cells were identified in gingival tissues, more Th1 and Th17 cells were found in the CP group, whereas more Th2 and Treg cells were found in the PH group. Although there was no significant difference in OPG expression between the two groups, the RANKL/OPG ratio in the CP group was higher than that in the PH group. The linear regression analysis showed that the presence of more Th1 and Th17 cells correlated with a higher RANKL/OPG ratio, whereas the presence of more Th2 cells correlated with a lower RANKL/OPG ratio. Th1 and Th17 cells are positively correlated and Th2 cells are negatively correlated with the RANKL/OPG ratio. Our data suggest that T‐helper cell polarization is closely linked to the RANKL/OPG ratio in gingival tissues from chronic periodontitis patients.

Evidence for the important role of inflammation in xenotransplantation

There is increasing evidence of a sustained state of systemic inflammation after pig-to-nonhuman primate (NHP) xenotransplantation (that has been termed systemic inflammation in xenograft recipients [SIXR]). Increases in inflammatory markers, e.g., C-reactive protein, histones, serum amyloid A, D-dimer, cytokines, chemokines, and a decrease in free triiodothyronine, have been demonstrated in the recipient NHPs. The complex interactions between inflammation, coagulation, and the immune response are well-recognized, but the role of inflammation in xenograft recipients is not fully understood. The evidence suggests that inflammation can promote the activation of coagulation and the adaptive immune response, but the exact mechanisms remain uncertain. If prolonged xenograft survival is to be achieved, anti-inflammatory strategies (e.g., the administration of anti-inflammatory agents, and/or the generation of genetically-engineered organ-source pigs that are protected from the effect of inflammation) may be necessary to prevent, control, or negate the effect of the systemic inflammation that develops in xenograft recipients. This may allow for a reduction in the intensity of exogenous immunosuppressive therapy. If immunological tolerance to a xenograft is to be obtained, then control of inflammation may be essential.

Matrix metalloproteinases gene polymorphism haplotype is a risk factor to implant loss: A case-control study

BACKGROUND

Dental implants consist in the treatment of choice to replace tooth loss. The knowledge that implant loss tends to cluster in subsets of individuals may indicate that host response is influenced by genetic factors. Matrix metalloproteinases (MMPs) are enzymes that contribute to degradation and removal of collagen from extracellular matrix.

PURPOSE

This case-control study aimed to investigate the haplotypic combination of MMP polymorphism (rs1144393, rs1799750, rs3025058, and rs11225395) and implant loss.

MATERIALS AND METHODS

Two hundred nonsmokers subjects were matched by gender, age, implant number and position and divided in control group, 100 patients with one or more healthy implants, and test group, and 100 patients with one or more implant failures. Genomic DNA was extracted from saliva and genotypes were obtained by PCR-RFLP.

RESULTS

A significant association of rs1799750 (MMP-1) and rs11225395 (MMP-8) polymorphism on early implant loss was demonstrated (P ≤ 0.001). Global haplotype analysis indicated a significant difference between both groups (P < 0.0001). Haplotype T-A-GG-5A-C had a statistically significant risk effect, while haplotype C-A-G-6A-C andT-G-2G-5A-C had a protective effect in implant loss.

CONCLUSIONS

The results of this study showed that MMPs haplotype are a risk factor to early implant loss.