Evaluation of peri-implant mucosa: clinical, histopathological and immunological aspects

Histological and Immunohistochemical Analysis of Peri-Implant Soft and Hard Tissues in Patients with Peri-Implantitis

Currently, researchers are focused on the study of cytokines as predictive biomarkers of peri-implantitis (PI) in order to obtain an early diagnosis and prognosis, and for treatment of the disease. The aim of the study was to characterize the peri-implant soft and hard tissues in patients with a peri-implantitis diagnosis. A descriptive observational study was conducted. Fifteen soft tissue (ST) samples and six peri-implant bone tissue (BT) samples were obtained from 13 patients who were diagnosed with peri-implantitis. All the samples were processed and embedded in paraffin for histological and immunohistochemical analyses. A descriptive and quantitative analysis of mast cells and osteocytes, A proliferation-inducing ligand (APRIL), B-cell activating factor (BAFF), osteonectin (ON), and ∝-smooth muscle actin (∝-SMA) was performed. We observed the presence of mast cells in peri-implant soft tissue in all samples (mean 9.21 number of mast cells) and osteocytes in peri-implant hard tissue in all samples (mean 37.17 number of osteocytes). The expression of APRIL-ST was 32.17% ± 6.39%, and that of APRIL-BT was 7.09% ± 5.94%. The BAFF-ST expression was 17.26 ± 12.90%, and the BAFF-BT was 12.16% ± 6.30%. The mean percentage of ON was 7.93% ± 3.79%, and ∝-SMA was 1.78% ± 3.79%. It was concluded that the expression of APRIL and BAFF suggests their involvement in the bone resorption observed in peri-implantitis. The lower expression of osteonectin in the peri-implant bone tissue can also be associated with a deficiency in the regulation of bone remodeling and the consequent peri-implant bone loss.

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.

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.

Immunohistochemical assessment of the peri-implant soft tissue around different abutment materials: A human study

BACKGROUND

Soft tissue reaction to dental implant abutments influences the sustainability of restoration. Several abutment materials, such as titanium and gold alloy, have been introduced for strength and esthetic solutions. Zirconia and titanium-base abutments have also become popular in recent years due to high esthetic demands.

PURPOSE

To investigate the immune cell infiltration into the soft tissue in response to different abutment materials.

MATERIALS AND METHODS

Twenty dental implants were placed in the posterior regions of 17 patients. Titanium, zirconia, gold alloy, and titanium-base were randomly selected for each patient on the day of surgery. After 8 weeks of healing, the abutments were removed along with 1 mm of peri-implant soft tissue. Immunohistochemical assessment was performed using labeled streptavidin-biotin to identify T cells, B cells, macrophages, plasma cells, and microvascular infiltration.

RESULTS

Gold alloy demonstrated an overall higher inflammatory cell infiltration and highest number of CD3⁺ , CD20⁺ , and CD 68⁺ cells (P value <.05). The number of plasma cell and new microvascular infiltrations among abutment materials was not significantly different.

CONCLUSION

Titanium, titanium-base, and zirconia abutments showed comparable infiltration profiles; gold alloy abutments showed the highest B-cell, T cell, and macrophage infiltration. None of the abutment materials caused clinical inflammation; hence, they can be effectively used.

Treg and TH17 link to immune response in individuals with peri-implantitis: a preliminary report

BACKGROUND AND OBJECTIVES

Treg and TH17 cells influence the inflammatory process in periodontal diseases and could also play in a similar pattern, an essential role in immune-inflammatory mechanisms involved in the destruction of the peri-implant tissues, peri-implantitis. Therefore, this study evaluated the levels of RORγT and FOXP3 gene expression in subjects with peri-implantitis and healthy peri-implant tissues.

METHODS

A total of 35 subjects with implant-supported restorations in both diseased and healthy clinical conditions (n = 15 healthy; n = 20 peri-implantitis) were included in this study. Peri-implantitis was defined as probing depth > 5 mm, bleeding on probing and/or suppuration, and peri-implant bone loss >4 mm. Peri-implant tissue biopsies were collected for analysis of the mRNA, RORγT, and FOXP3 expression levels. The samples were submitted to total RNA extraction, treatment with DNAse, and cDNA synthesis. Subsequently, real-time PCR reaction was performed to evaluate the levels of RORγT and FOXP3 gene expression to the reference gene. These were analyzed by the non-parametric Mann-Whitney method with a level of significance of 5%.

RESULTS

Higher gene expression levels of the transcription factors RORγT and FOXP3 were detected in the tissues affected by peri-implantitis when compared with healthy tissues (p < 0.05).

CONCLUSIONS

The present study demonstrated the possible existence of a hybrid TH17-Treg profile, based on the gene expression of transcription factors inducing differentiation of these cells. Further studies must be designed to gain a better understanding of the immunological mechanisms involved in the pathogenesis of peri-implantitis.

CLINICAL RELEVANCE

The levels of RORγT and FOXP3 transcription factors that were linked to cells with the FOXP3+RORγT+ phenotype could be used as a predictor of peri-implantitis progression.

Interleukin-10 and Interleukin-1β Cytokines Expression in Leukocytes of Patients with Chronic Peri-Mucositis

BACKGROUND The purpose of the present research is to analyze the effect of polyphenols and flavonoids substrat (PFS) from plants Calendula officinalis, Salvia fruticosa, Achillea millefolium, and propolis as immunomodulatory in the production of interleukin (IL)-1ß and IL-10 in peripheral blood leukocytes medium (PBLM) in patients who were diagnosed with mucositis of peri-implant tissue compared to patients with healthy implant tissue. It was hypothesized that IL-1ß and IL-10 contribute to the inflammation processes noticed in the diseases of peri-implant tissues. MATERIAL AND METHODS Sixty non-smoking patients were included in this study: patients with healthy implants (HP group) and patients with peri-implant mucositis (MP group). Peri-mucositis was diagnosed by radiologic and clinical examination. The PBLM from MP were treated with PFS at various concentrations. The levels of IL-10 and IL-1ß excreted by the PBLM stimulated and unstimulated with viable Porphyromonas gingivalis test-tube were committed by the enzyme amplified immunoassay sensitivity method. RESULTS Unstimulated and stimulated PBLM and treatment with 5.0 mg/mL or 10.0 mg/mL of PFS in the MP group produced significantly higher levels IL-10 (P<0.001) that analogous mediums of the HP group. The levels of IL-1ß decreased more considerably in the stimulated PBLM of the MP group than in those of HP group (P<0.001) after the treatment with PFS at only 10.0 mg/mL concentration. CONCLUSIONS Theses results suggest that the solution of PFS might offer a new potential for the development of a new therapeutic path to prevent and treat peri-implant mucositis.

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.

Analysis of CD15, CD57 and HIF-1α in biopsies of patients with peri-implantitis

Peri-implantitis is an infectious disease characterized by inflammation of the tissues surrounding the implant, bleeding on probing with or without suppuration, and bone loss. Peri-implant lesions contain a leukocyte infiltrate of plasma cells, lymphocytes, macrophages and neutrophils. A survey of the literature did not show any studies reporting an association between hypoxia and peri-implantitis. The aim of the present cross-sectional study was to evaluate histological changes and immunostaining for CD15, CD57 and HIF-1α in the peri-implant mucosa of patients with and without peri-implantitis. Mucosal biopsies were obtained from 18 patients with peri-implantitis and 10 control subjects without peri-implantitis at a private health care center between 2010 and 2012. The sections were fixed in 10% buffered formalin, processed and embedded in paraffin for histopathological and immunohistochemical study. Acanthosis, spongiosis and exocytosis were observed in both groups, with no significant difference between them. The peri-implantitis group showed increased immunostaining for CD15, a neutrophil marker, and HIF-1α, a tissue hypoxia marker, but no significant difference in immunostaining for CD57, a Natural Killer cell marker. The increase in neutrophil (CD15) and hypoxia (HIF-1α) markers in patients with peri-implantitis suggests an active participation of neutrophils and hypoxia in the pathogenesis of this disease. Since the present study was the first to evaluate the expression of CD15, CD57 and HIF-1α in peri-implant tissues, further studies should be performed to better understand the role of these molecules in peri-implantitis.