Can peri-implant crevicular fluid assist in the diagnosis of peri-implantitis? A systematic review and meta-analysis

CXCL5/CXCL8 induces neutrophilic inflammation in peri-implantitis

OBJECTIVE AND BACKGROUND

This research aimed to examine the role of C-X-C motif chemokine ligand 5 (CXCL5) and C-X-C motif chemokine ligand 8 (CXCL8; also known as IL-8) in neutrophilic inflammation triggered by peri-implantitis and to shed light on the underlying mechanisms that link them to the development of this condition.

MATERIALS

This study included 40 patients who visited the Department of Periodontology at Kyungpook University Dental Hospital. They were divided into two groups based on their condition: healthy implant (HI) group (n = 20) and peri-implantitis (PI) group (n = 20). Biopsy samples of PI tissue were collected from the patients under local anesthesia. HI tissue was obtained using the same method during the second implant surgery. To construct libraries for control and test RNAs, the QuantSeq 3' mRNA-Seq Library Prep Kit (Lexogen, Inc., Austria) was used according to the manufacturer's instructions. Samples were pooled based on representative cytokines obtained from RNA sequencing results and subjected to Reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Hematoxylin and eosin staining, and immunohistochemistry (IHC) analysis were performed to visually assess expression levels and analyze tissue histology. Student's t-test was employed to conduct statistical analyses.

RESULTS

Initially, heatmaps were used to examine gene expression variations between the HI and PI groups based on the results of RNA sequencing. Notably, among various cytokines, CXCL5 and CXCL8 had the highest expression levels in the PI group compared with the HI group, and they are known to be associated with inflammatory responses. In the gingival tissues, the expression of genes encoding cytokines such as interleukin (IL)-1β, tumor necrosis factor-alpha (TNF)-α, interleukin (IL)-6, and CXCL5/CXCL8 was assessed via RT-qPCR. The mRNA expression level of CXCL5/CXCL8 significantly increased in the PI group compared with the HI group (p < .045). Contrarily, the mRNA expression level of interleukin 36 receptor antagonist (IL36RN) significantly decreased (p < .008). IHC enabled examination of the distribution and intensity of CXCL5/CXCL8 protein expression within the tissue samples. Specifically, increased levels of CXCL5/CXCL8 promote inflammatory responses, cellular proliferation, migration, and invasion within the peri-implant tissues. These effects are mediated through the activation of the PI3K/Akt/NF-κB signaling pathway.

CONCLUSIONS

This study found that the PI sites had higher gene expression level of CXCL8/CXCL5 in the soft tissue than HI sites, which could help achieve more accurate diagnosis and treatment planning.

Development and applications of peri-implantitis mouse models

OBJECTIVE

Peri-implantitis is one of the most common complications of implants. However, its pathogenesis has not been clarified. In recent years, mouse models are gradually being used in the study of peri-implantitis. This review aims to summarize the methods used to induce peri-implantitis in mice and their current applications.

METHOD

Articles of peri-implantitis mouse models were collected. We analyzed the various methods of inducing peri-implantitis and their application in different areas.

RESULTS

Most researchers have induced peri-implantitis by silk ligatures. Some others have induced peri-implantitis by Pg gavage and LPS injection. Current applications of peri-implantitis mouse models are in the following areas: investigation of pathogenesis and exploration of new interventions, comparison of peri-implantitis with periodontitis, the interaction between systemic diseases and peri-implantitis, etc. CONCLUSION: Silk ligature for 2-4 weeks, Pg gavage for 6 weeks, and LPS injection for 6 weeks all successfully induced peri-implantitis in mice. Mice have the advantages of mature gene editing technology, low cost, and short time to induce peri-implantitis. It has applications in the study of pathogenesis, non-surgical treatments, and interactions with other diseases. However, compared with large animals, mice also have a number of disadvantages that limit their application.

Spectroscopic insights into peri-implant mucositis and peri-implantitis: unveiling peri-implant crevicular fluid profiles using surface enhanced Raman scattering

The precise identification and differentiation of peri-implant diseases, without the need for intrusive procedures, is crucial for the successful clinical treatment and overall durability of dental implants. This work introduces a novel approach that combines surface-enhanced Raman scattering (SERS) spectroscopy with advanced chemometrics to analyse peri-implant crevicular fluid (PICF) samples. The primary purpose is to offer an unbiased evaluation of implant health. A detailed investigation was performed on PICF samples obtained from a cohort of patients exhibiting different levels of peri-implant health, including those with healthy implants, implants impacted by peri-implantitis, and implants with peri-implant mucositis. The obtained SERS spectra were analysed using canonical-powered partial least squares (CPPLS) to identify unique chemical characteristics associated with each inflammatory state. Significantly, our research findings unveil the presence of a common inflammatory SERS spectral pattern in cases of peri-implantitis and peri-implant mucositis. Furthermore, the SERS-based scores obtained from CPPLS were combined with established clinical scores and subjected to a linear discriminant analysis (LDA) classifier. Repeated double cross-validation was used to validate the method's capacity to discriminate different implant conditions. The integrated approach showcased high sensitivity and specificity and an overall balanced accuracy of 92%, demonstrating its potential to serve as a non-invasive diagnostic tool for real-time implant monitoring and early detection of inflammatory conditions.

The Influence of Genetic Polymorphisms on the Expression of Interleukin-1beta, Prostaglandin E2 and Tumor Necrosis Factor Alpha in Peri-Implant Crevicular Fluid: A Cross-Sectional Study

The aim of this study was to evaluate the possible relationships between polymorphisms in the interleukin-1 (IL-1) A, IL-1B, and IL-1RN genes and concentrations of the inflammatory mediators IL-1β, tumor necrosis factor-alpha (TNF-α), and prostaglandin E2 (PGE2) in peri-implant crevicular fluid (PICF). A cross-sectional analytical study was conducted on 51 patients with dental implants. Samples from the buccal mucosa were obtained, and genetic analysis was performed using the real-time polymerase chain reaction (PCR) technique for IL-1A and IL-1B and PCR and restriction fragment length polymorphism analysis for IL-1RN. For the biochemical analysis, the concentrations of IL-1β and TNF-α were analyzed using multiplexed fluorescent sphere immunoassays, and PGE2 by enzyme-linked immunosorbent assay. In patients with detected IL-1RN polymorphism, there was an increase in the concentration of the three mediators with statistically significant differences in the mean values of TNF-α and PGE2, regardless of peri-implant health status (p = 0.002 and p = 0.049, respectively). The concentrations of all three mediators were positively and significantly correlated (IL-1β vs. TNF-α Rho = 0.480, p < 0.001; IL-1β vs. PGE2 Rho = 0.382, p = 0.006; and TNF-α vs. PGE2 Rho = 0.528, p < 0.001). We can conclude that the IL-1RN polymorphism exerts an influence on the PICF immune response, which may explain the influence of this genetic polymorphism on the occurrence of peri-implantitis.

An In Vivo Investigation of Non-Metallic vs. Metallic Hand Scalers on Zirconia Implant-Supported Crowns: A Year-Long Analysis of Peri-Implant Maintenance

This study examined whether the degree of abutment surface modification that may occur with regular periodontal instrumentation has a clinical impact in terms of increased plaque accumulation and increased peri-implant tissue inflammation on zirconia implant abutments. Thirteen patients who had zirconia implant crowns were recruited in this randomized clinical trial. Each patient acted as their control and had either the buccal or lingual surface of their screw-retained implant restoration scaled with a metallic scaler and the other surface with a non-metallic scaler at 3, 6, 9, and 12 months. Cytokine testing of the peri-implant crevicular fluid was completed at 0, 3, and 12 months for IL-2, IL-4, IL-6, IL-8, IL-10, TNF-α, or IFNγ. Implant crowns were removed at 12 months and evaluated under an atomic force microscope for the average roughness (Ra). The implant crowns were polished and re-inserted. The results were analyzed using the Kruskal-Wallis test, and post hoc tests were conducted with a significance level of α = 0.05. Significant differences in surface roughness (Ra) were observed between the metallic and non-metallic scalers. The median Ra values were 274.0 nm for metallic scalers and 147.1 nm for non-metallic scalers. However, there were no significant differences between the type of scaler used and the amount of clinical inflammation or cytokine production. Metallic scalers produced deeper, more aggressive surface alterations to the abutment/crown zirconia surface, but there was no statistically significant difference between the degree of surface alterations, amount of BOP, and the amplitude of cytokine inflammation produced.

Identification of novel candidate biomarkers related to immune cell infiltration in peri-implantitis

OBJECTIVE

The present study was performed to identify key biomarkers associated with immune cell infiltration in peri-implantitis through bioinformatic analyses.

METHODS

Six peri-implantitis soft tissue samples and six healthy gingiva samples were obtained from GSE106090, and were used to identify immune-associated differentially expressed genes (DEGs) in peri-implantitis. The candidate biomarkers associated with immune cell infiltration were examined by immunohistochemical staining.

RESULTS

We identified 2089 upregulated and 2173 downregulated genes. Upregulated DEGs were significantly associated with immune response. Ten key candidate biomarkers were identified in the PPI network, including IL1B, TLR2, TLR4, CCL4, CXCL8, IL10, IL6, CD4, CCL3, and PTPRC. The expression level of the 10 genes increased in peri-implantitis soft tissue samples compared with healthy gingiva samples. The proportion of CD4+ T cells, iTreg, and Tfh in infiltration immune cells increased in peri-implantitis soft tissue samples and were positively correlated with the expression level of candidate biomarkers TLR4, CCL3, CXCL8, and IL1B. Immunohistochemistry showed that there were more lymphocytes in peri-implantitis soft tissue samples, with an increased expression level of TLR4, CCL3, CXCL8, and IL1B.

CONCLUSION

Identification of four novel diagnostic biomarkers was helpful for revealing the molecular mechanisms and could serve as a risk predictor for the immune microenvironment in peri-implantitis.

A novel nonsurgical therapy for peri-implantitis using focused pulsed electromagnetic field: A pilot randomized double-blind controlled clinical trial

Pulsed electromagnetic field (PEMF) therapy modulates the immune response and is successfully used in orthopedics to treat osteoarthritis and improve bone regeneration. This may suggest that this treatment may consequently reduce peri-implant soft tissue inflammation and marginal bone loss. To compare clinical, radiographic, and immunological results following nonsurgical treatment for peri-implantitis with or without PEMF therapy. Patients with peri-implantitis were included: pocket probing depth (PPD) between 6 and 8 mm with bleeding on probing (BOP); crestal bone loss between 3 and 5 mm. A novel healing abutment that contained active (test) or inactive (control) PEMF was connected. PEMF was administered via the abutment at exposure ratio of 1/500-1/5000, intensity: 0.05-0.5 mT, frequency: 10-50 kHz for 30 days. Nonsurgical mechanical implant surface debridement was performed. Patients were examined at baseline, 1 and 3 months. Clinical assessment included: plaque index, BOP, PPD, recession, and bone crest level which was radiography measured. Samples of peri-implant crevicular fluid were taken to analyze interleukin-1β (IL-1β). Twenty-three patients (34 implants; 19 control, 15 test) were included. At the follow-up, mean crestal bone loss was lower in the test group at 1 and 3 months (2.48 mm vs. 3.73 mm, p < 0.05 and 2.39 vs. 3.37, p < 0.01). IL-1β levels were also lower in the test group at 2 weeks (72.86 pg/mL vs. 111.7, p < 0.05). Within all the limitation of this preliminary study, the test group improved clinical parameters after a short-term period compared to the control group.

Effects of customized CAD/CAM abutments on cytokine levels in peri-implant crevicular fluid during early implant healing: a pilot study

OBJECTIVES

This study aimed to assess levels of biomarkers associated with inflammation and tissue destruction in peri-implant crevicular fluid (PICF) of implants provided with customized or standard healing abutments during early implant healing.

MATERIALS AND METHODS

Thirty implants were placed in 22 patients with partial posterior edentulism. Subsequently, test group implants (n=15) received one-piece titanium abutments that were fabricated using computer-aided design/computer-aided manufacturing (CAD/CAM). Control group implants (n=15) were provided with standard abutments. PICF collection and standardized periapical radiographs were carried out at suture removal one week later, following crown delivery after 3 months and at 6 months. Expression of C-reactive protein (CRP), interferon-γ, tumor necrosis factor (TNF)-α, interleukin (IL)-1α, IL-1β, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12A, IL-17A, macrophage inflammatory protein (MIP)-1α, matrix metalloproteinase (MMP)-13, osteopontin, osteoactivin, Receptor Activator of NF-κB (RANK), and TGF-β were analyzed using a multiplex ELISA kit.

RESULTS

Both groups showed a significant decrease in protein expression of CRP, IL-1β, IL-6, IL-8, MIP-1α, osteopontin, osteoactivin, and TGF-β, while MMP-13 levels increased during the observation period. A rise in OPG and RANK levels was detected among customized abutments. Expression of CRP was higher, whereas IL-1β, IL-1α, and MIP-1α were decreased in control compared to test group implants after 6 months. Marginal bone loss did not depend on abutment modality.

CONCLUSIONS

Both abutment types showed distinctive temporal expression of inflammatory biomarkers during 6 months following implant placement.

TRIAL REGISTRATION

ISRCTN98477184, registration date 18/05/2022 CLINICAL RELEVANCE: Customized healing abutments exert similar effects on inflammation during early implant healing compared to standard healing abutments.

Biomaterial engineering surface to control polymicrobial dental implant-related infections: focusing on disease modulating factors and coatings development

INTRODUCTION

Peri-implantitis is the leading cause of dental implant loss and is initiated by a polymicrobial dysbiotic biofilm formation on the implant surface. The destruction of peri-implant tissue by the host immune response and the low effectiveness of surgical or non-surgical treatments highlight the need for new strategies to prevent, modulate and/or eliminate biofilm formation on the implant surface. Currently, several surface modifications have been proposed using biomolecules, ions, antimicrobial agents, and topography alterations.

AREAS COVERED

Initially, this review provides an overview of the etiopathogenesis and host- and material-dependent modulating factors of peri-implant disease. In addition, a critical discussion about the antimicrobial surface modification mechanisms and techniques employed to modify the titanium implant material is provided. Finally, we also considered the future perspectives on the development of antimicrobial surfaces to narrow the bridge between idea and product and favor the clinical application possibility.

EXPERT OPINION

Antimicrobial surface modifications have demonstrated effective results; however, there is no consensus about the best modification strategy and in-depth information on the safety and longevity of the antimicrobial effect. Modified surfaces display recurring challenges such as short-term effectiveness, the burst release of drugs, cytotoxicity, and lack of reusability. Stimulus-responsive surfaces seem to be a promising strategy for a controlled and precise antimicrobial effect, and future research should focus on this technology and study it from models that better mimic clinical conditions.

Current Molecular, Cellular and Genetic Aspects of Peri-Implantitis Disease: A Narrative Review

(1) Background: Peri-implantitis is a multi-factorial disease with an inflammatory background that occurs in both soft and hard tissues surrounding implants. In recent years, the understanding of the cellular, molecular and genetic background of peri-implantitis has broadened. This study aims to summarize the currently available articles on the subject and highlight the most recent advances over the last 20 years. (2) Methods: For this study, the Embase and PubMed libraries were searched using the keywords: ("peri-implantitis" AND "cytokine" OR "genetics" OR "cellular") and ("peri-implantitis" AND "cytokine" OR "genetics" OR "cellular" AND "risk factors"). The search revealed a total of 3013 articles (992 from PubMed, 2021 from Embase). Following screening of the titles and abstracts and full-text reads, 55 articles were included. (3) Results: In peri-implantitis IL-6, IL-1β, TNF-α, MMP-8 and their genetic variations appear to be the most important cytokines in relation to not only pathogenesis, but also their potential diagnostic capabilities. Epithelial and inflammatory cells, along with those of the bone lineage, are prime cellular elements found in peri-implantitis. (4) Conclusions: A wide array of cells stand behind peri-implantitis, as well as cytokines and their genetic variations that take part in the process. However, the growing interest in this topic has led to the introduction of specific new diagnostic tools to enable a better understanding of patients' responses to treatment and, in turn, to even enable prediction of the risk of developing peri-implant disease.

Sitagliptin attenuates Porphyromonas gingivalis virulence and inflammatory response in macrophage on titanium

BACKGROUND

In peri-implantitis, Porphyromonas gingivalis and macrophage play important roles. The aim of this study was to detect the attenuating effect of an anti-diabetic drug sitagliptin on Porphyromonas gingivalis virulence and inflammatory response in macrophage on titanium discs.

MATERIALS AND METHODS

Porphyromonas gingivalis and macrophage were cultured on titanium discs. Antibacterial and antibiofilm activities of sitagliptin were assessed and the morphology of Porphyromonas gingivalis was observed by SEM. Bacterial early adhesion, aggregation, hemolysis and Porphyromonas gingivalis virulence factors mRNA expression were assessed to preliminarily investigate the mechanisms of action. Flow cytometry assay, qRT-PCR assay and ELISA were used to assess the anti-inflammatory effect of sitagliptin on Porphyromonas gingivalis lipopolysaccharide-stimulated macrophage.

RESULTS

The present study demonstrated the inhibiting effect of sitagliptin on the growth, biofilm and virulence factors of Porphyromonas gingivalis and the protective effect on the Porphyromonas gingivalis lipopolysaccharide-induced polarization in macrophage. And we also confirmed the anti-inflammatory effect of sitagliptin on the secretion of inflammation-related factors in macrophage.

CONCLUSIONS

Sitagliptin possesses the attenuating effect on Porphyromonas gingivalis virulence and inflammatory response in Porphyromonas gingivalis lipopolysaccharide-stimulated macrophage on titanium.

Peri-implant diseases diagnosis, prognosis and dental implant monitoring: a narrative review of novel strategies and clinical impact

BACKGROUND

The diagnosis of peri-implantar and periodontal relies mainly on a set of clinical measures and the evaluation of radiographic images. However, these clinical settings alone are not sufficient to determine, much less predict, periimplant bone loss or future implant failure. Early diagnosis of periimplant diseases and its rate of progress may be possible through biomarkers assessment. Once identified, biomarkers of peri-implant and periodontal tissue destruction may alert the clinicians before clinical signs show up. Therefore, it is important to consider developing chair-side diagnostic tests with specificity for a particular biomarker, indicating the current activity of the disease.

METHODS

A search strategy was created at Pubmed and Web of Science to answer the question: "How the molecular point-of-care tests currently available can help in the early detection of peri-implant diseases and throws light on improvements in point of care diagnostics devices?"

RESULTS

The PerioSafe® PRO DRS (dentognostics GmbH, Jena) and ImplantSafe® DR (dentognostics GmbH, Jena ORALyzer® test kits, already used clinically, can be a helpful adjunct tool in enhancing the diagnosis and prognosis of periodontal/peri-implantar diseases. With the advances of sensor technology, the biosensors can perform daily monitoring of dental implants or periodontal diseases, making contributions to personal healthcare and improve the current status quo of health management and human health.

CONCLUSIONS

Based on the findings, more emphasis is given to the role of biomarkers in diagnosing and monitoring periodontal and peri-implant diseases. By combining these strategies with traditional protocols, professionals could increase the accuracy of early detection of peri-implant and periodontal diseases, predicting disease progression, and monitoring of treatment outcomes.

Osteogenic markers in peri-implant crevicular fluid in immediate and delayed-loaded dental implants: A randomized controlled trial

INTRODUCTION

The study evaluates the levels of matrix metalloprotease-8 (MMP-8), and Cathepsin-K (CatK) in peri-implant crevicular fluid (PICF) among patients with immediate loaded (IL) and delayed-loaded (DL) implants at different time points to know the inflammation and osteogenic status.

METHODS

The study population consisted of two groups (n = 25, each group) with a mean age of 28.7 ± 3.5 years, and PICF was collected. MMP-8 and CatK levels were quantified through ELISA.

RESULTS

We observed the concentrations of inflammatory markers (MMP-8 and CatK) at three time points in the IL and DL groups. The mean concentration of MMP-8 in the IL group was 9468 ± 1230 pg/mL, 5547 ± 1088 pg/mL, and 7248 ± 1396 pg/mL at 2 weeks, 3 months, and 12 months, respectively; while in the DL group was 10 816 ± 779.7 pg/mL, 9531 ± 1245 pg/mL, and 9132 ± 1265 pg/mL at 2 weeks, 3 and 12 months, respectively. The mean concentration of Cat-K in the IL group was observed at 422.1 ± 36.46 pg/mL, 242.9 ± 25.87 pg/mL, and 469 ± 75.38 pg/mL at 2 weeks, 3, and 12 months, whereas in the DL group was 654.6 ± 152.9 pg/mL, 314.7 ± 28.29 pg/mL, and 539.8 ± 115.1 pg/mL at 2 weeks, 3 months and 12 months, respectively.

CONCLUSION

In this study, the levels of CatK and MMP-8 levels decline at 12 months in both groups, and the IL group shows lower values compared to the DL group; however, no significant changes were observed after analyses were adjusted for multiple comparisons (p > 0.025). Therefore, there is not much difference observed in the inflammation process between immediate and delayed loading. (Clinical trial identifier: CTRI/2017/09/009668).

Effect of laser-assisted reconstructive surgical therapy of peri-implantitis on protein biomarkers and bacterial load

OBJECTIVES

This randomized clinical trial assessed changes in protein biomarker levels and bacterial profiles after surgical reconstructive therapy of peri-implantitis and investigated whether the adjunctive use of Er:YAG laser impacts protein biomarker and microbial outcomes.

MATERIALS AND METHODS

Twenty-four patients received surgical reconstructive therapy for peri-implantitis with guided bone regeneration following mechanical debridement with (test) or without (control) the adjunctive irradiation of Er:YAG laser. Bacterial and peri-implant crevicular fluid (PICF) samples were collected over 6 months and analyzed with bacterial qPCR and luminex multiplex assays.

RESULTS

Surgical reconstructive treatment significantly affected the concentration of PICF protein biomarkers, including a 50% reduction in IL-1β between 2 and 4 weeks (p < .0001). Both MMP-9 (p < .001) and VEGF (p < .05) levels steadily decreased after treatment. In the laser group, the peak increase in IL-1β was attenuated at 2 weeks, followed by significant reduction in MMP-9 (p < .01) and VEGF (p < .05) across all follow-up appointments compared with the control nonlaser group. The total bacterial load was reduced 2 weeks after treatment, especially in the laser group, but recolonized to presurgical levels after 4 weeks in both groups (p < .01). The composition of selective pathogens varied significantly over the follow-up, but recolonization patterns did not differ between groups.

CONCLUSIONS

Reconstructive therapy of peri-implantitis significantly altered PICF protein biomarker and microbial levels during the healing process. The adjunctive use of Er:YAG laser significantly modulated the inflammatory response through reduced levels of MMP-9 and VEGF during the postsurgical period. The bacterial load was reduced immediately after therapy, but recolonization was observed by 4 weeks in both groups.

On Peri-Implant Bone Loss Theories: Trying To Piece Together the Jigsaw

This review aims to explore the plausibility of new theories on the etiopathogenesis of marginal bone loss (MBL) and peri-implantitis (PI) and to discuss possible underlying pathogenic mechanisms. The former concept of osteointegration of dental implants can now be conceptualized as a foreign body response histologically characterized by a bony demarcation in combination with chronic inflammation. Different risk factors can provoke additional inflammation and, therefore, pro-inflammatory cytokine release in soft tissues and bone, leading to an overpass of the threshold of peri-implant bone defensive and regenerative capacity. Progressive bone loss observed in MBL and PI is ultimately due to a localized imbalance in the receptor activator of nuclear factor kappaB ligand (RANKL)/Receptor activator of nuclear factor κ B (RANK)/osteoprotegerin (OPG) pathway in favor of increased catabolic activity. The genetic background and the severity and duration of the risk factors could explain differences between individuals in the threshold needed to reach an imbalanced scenario. MBL and PI pathogenesis could be better explained by the "inflammation-immunological balance" theory rather than a solely "infectious disease" conception. The link between the effect of biofilm and other risk factors leading to an imbalanced foreign body response lies in osteoclast differentiation and activation pathways (over)stimulation.

Can Peri-Implant Marginal Bone Loss Progression and a-MMP-8 Be Considered Indicators of the Subsequent Onset of Peri-Implantitis? A 5-Year Study

The aim of this retrospective study was to investigate the relationship between the amount of early bone remodeling, the marginal bone loss (MBL) progression, and the peri-implant sulcular fluid concentration of active metalloproteinase-8 (a-MMP-8) and the incidence of peri-implantitis (P) over 5 years of implant function. It has been documented that dental implants with a high degree of early marginal bone loss (MBL) are likely to achieve additional increased MBL during function. Moreover, it has been speculated that early increased MBL might be a predictive factor for the subsequent onset of peri-implant inflammatory diseases. Clinical and radiographic data at implant placement (T0) and restoration delivery (TR) at 6 months (T1), 2 years (T2), and 5 years (T5) post-loading were retrospectively collected. MBL levels/rates (MBLr) and peri-implant sulcular fluid levels/rates of a-MMP-8 were assessed at TR, T1, T2, and T5. Implants were divided into two groups: group 1 with peri-implantitis (P+) and group 2 without peri-implantitis (P−). A multi-level simple binary logistic regression, using generalized estimation equations (GEEs), was implemented to assess the association between each independent variable and P+. A receiver operating characteristics (ROC) curve was used to evaluate an optimal cutoff point for T1 MBL degree and a-MMP-8 level to discriminate between P+ and P− implants. A total of 80 patients who had received 80 implants between them (39 implants with a laser-microtextured collar surface (LMS) and 41 implants with a machined collar surface (MS)) were included. Periapical radiographs and a software package were used to measure MBL rates. Peri-implant sulcular implant fluid samples were analyzed by a chairside mouth-rinse test (ImplantSafe®) in combination with a digital reader (ORALyzer®). Twenty-four implants (six with an LMS and eighteen with an MS) were classified as P+. No statistically significant association was found between the amount of early bone remodeling, MBL progression, and MBLr and the incidence of peri-implantitis. Implants with a-MMP-8 levels >15.3 ng/mL at T1 presented a significantly higher probability of P+. The amount of early marginal bone remodeling cannot be considered as an indicator of the subsequent onset of P, whereas high a-MMP-8 levels 6 months after loading could have a distinct ability to predict P.

Calprotectin and N-telopeptide of Type I Collagen (NTx) as Gingival Crevicular Fluid (GCF) Biomarker in Peri-Implantitis Patients

Introduction: Formulation of various preventive and therapeutic strategies is possible only by a better understanding of the immune-inflammatory profile of peri-implant diseases. For understanding the changes and turnover of bone, various markers have been used in the past literature, out of which, N-telopeptide of Type I Collagen (NTx) is acknowledged to be the most reliable marker.

Aims and objectives: Assessment of calprotectin and NTx concentration in gingival crevicular fluid (GCF) around the implant sites in subjects suffering from peri-implantitis.

Materials and methods: In total, 70 healthy individuals were included in the present study. These patients had opted for dental implants within the last decade. After collecting the peri-implant crevicular fluid (PICF) and GCF, various examinations were carried out. PICF samples were obtained with the help of sterile paper available in the form of strips. The enzyme-linked immunosorbent assay (ELISA) technique was used for measuring the calprotectin and NTx. All the readings were obtained in nanograms per microliter of PICF. All the results were recorded and analyzed.

Results: The overall mean calprotectin and NTx values were observed to be in a significantly higher range within the sites suffering from peri-implantitis when compared with healthy locations. The calprotectin values and NTx levels were positively correlated with the mean values of periodontal parameters observed clinically.

Conclusion: Both calprotectin and NTx could be used as a biomarker signifying the presence of inflammation as well as bone resorption in patients suffering from peri-implantitis.

Bacterial-Specific Induction of Inflammatory Cytokines Significantly Decreases upon Dual Species Infections of Implant Materials with Periodontal Pathogens in a Mouse Model

Cytokine profiles are often perturbed after infections of medical implants. With a non-invasive in vivo imaging system, we report in a mouse model that interferon expression after infection of subcutaneous implants with Streptococcus oralis, Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, and Treponema denticola (alone or as a combination) was species-specific, persisted longer in the presence of implants, and notably decreased upon dual species infections. This type I interferon expression disappeared within two weeks; however, histology of implant–tissue interface indicated high recruitment of immune cells even after three weeks. This was suggestive that biomaterial-associated infections could have prolonged effects, including the systemic stimulation of inflammatory cytokines. The present study investigated the systemic impact of this chronic peri-implant inflammation on the systemic expression of inflammatory cytokines (23) using a multiplex assay. Initially, the cytokine measurement in murine fibroblasts exposed to periodontal pathogens remained limited to the expression of five cytokines, namely, IL-6, G-CSF, CXCL-1/KC, MCP-1 (MCAF), and IL-12 (p40). The systemic determination of cytokines in mice increased to 19 cytokines (IL-1α, IL-2, IL-3, IL-5, IL-6, IL-9, IL-12 (p40), IL-12 (p70), IL-13, IL-17A, CCL-11/Eotaxin, G-CSF, IFN-γ, CXCL1/KC, MCP-1 (MCAF), MIP-1α/CCL3, MIP-1β/CCL4, CCL5/RANTES, and TNF-α). Systemic induction of cytokines was species-specific in the mouse model. The cytokine induction from infected implants differed significantly from sole tissue infections and sterile implants. Notably, systemic cytokine induction decreased after infections with dual species compared to single species infections. These findings describe the systemic effect of chronic peri-implant inflammation on the systemic induction of inflammatory cytokines, and this effect was strongly correlated to the type and composition of initial infection. Systemic modulations in cytokine expression upon dual species infections exhibit an exciting pattern that might explain the complications associated with biomaterial-related infection in patients. Moreover, these findings validate the requirement of multispecies infections for pre-clinical studies involving animal models.

Expression of Interleukin-17, Tumor Necrosis Factor-Alpha, and Matrix Metalloproteinase-8 in Patients with Chronic Peri-Implant Mucositis

Background

The present study aimed to evaluate whether non-surgical treatment interferes with clinical parameters and local patterns of osteo-immunoinflammatory mediators (IL-17 and TNF-α) and matrix metalloproteinase-8 (MMP-8) that are found in peri-implant crevicular fluid (PICF) and biofilms during the progression of peri-implant mucositis.

Material/Methods

We selected 30 patients with peri-implant caused mucositis before (MP) and after treatment (TP) and 30 healthy people (HP) for the analysis of IL-17, TNF-α cytokine, and MMP-8 production in PICF and for analysis of colonization dynamics of periodontopathogenic bacteria in supra- and subgingival plaque samples. The levels of IL-17 and MMP-8 concentrations in samples were assayed by enzymatic immunosorbent assay (ELISA) and TNF-α levels were determined by enzyme amplified sensitivity immunoassay (EASIA) method in PICF. The micro-IDent test was used to detect 11 species of periodontopathogenic bacteria in subgingival biofilm.

Results

We found significantly (P<0.001) higher levels of IL-17, TNF-α, and MMP-8 in the PICF of the MP and TP groups in comparison to the HP group. A significant association was found in MP associated with Parvimonas micra, as TNF-α in PICF was significantly higher (P=0.034) than in patients without Parvimonas micra. TNF-α levels in the samples of PICF showed a moderate correlation with clinical parameters, including plaque index (PI) (P=0.007) and MMP-8 levels (P=0.001), in the MP group.

Conclusions

Assessment of levels of inflammatory cytokines in PICF can aid in the identification of peri-implant mucositis, which can assist in early diagnosis, prevention, and treatment.

Inflammatory effects of individualized abutments bonded onto titanium base on peri-implant tissue health: A randomized controlled clinical trial

BACKGROUND

In implant prosthodontics, computer-assisted design and computer-assisted manufacturing (CAD/CAM) zirconia abutments bonded onto titanium bases are frequently used in prosthetic dentistry. Unpolymerized monomer of the bonding material or the adhesive gap itself may have a negative effect on peri-implant tissue health. However, evidence addressing this problem is not available.

PURPOSE

The aim of the current trial was to study inflammatory effects of individualized abutments bonded onto titanium bases.

MATERIAL AND METHOD

A total of 24 patients with one test abutment and one control abutment each participated in this prospective, double-blind, randomized controlled clinical trial. Thereby, test abutments were CAD/CAM titanium abutments bonded onto titanium abutments (Ti-Base). As control abutments individualized, one-piece CAD/CAM titanium abutments were used. At abutment installation as well as 6 and 12 months thereafter bone level changes, clinical parameters as well as Il-1β levels were assessed.

RESULTS

Neither for bone level or clinical parameters nor for Il-1β levels, significant differences between test and control abutments could be found. However, in both groups Il-1β levels were significantly elevated at both the 6 and 12 months follow-up compared to baseline.

CONCLUSION

Within the limits of this RCT, it can be concluded that effects on the inflammatory state of peri-implant tissues do not differ between individualized abutments bonded onto Ti-Bases and individualized one-piece abutments.

Association Between Tumor Necrosis Factor-α (G-308A) Polymorphism and Chronic Periodontitis, Aggressive Periodontitis, and Peri-implantitis: A Meta-analysis

OBJECTIVE

Chronic periodontitis (CP), aggressive periodontitis (AP), and peri-implantitis (PI) are chronic inflammatory diseases. Tumor necrosis factor-α (TNF-a) is an effective immune inflammatory mediator. Several studies have been conducted to explore the association between the TNF-α (G-308A) polymorphism and susceptibility to CP, AP, and PI. Our objective was to examine whether the TNF-α (G-308A) polymorphism is related to these diseases.

METHODS

We conducted a meta-analysis to investigate the association between the TNF-α (G-308A) polymorphism and CP, AP, and PI. The PubMed, Embase, CNKI, and Web of Science electronic databases were searched for studies published from inception to August 11, 2020; the reference lists of included studies were also searched. The included studies were assessed in the following genetic models: dominant model, recessive model, allelic model, heterozygous model, and homozygous model.

RESULTS

Forty articles (50 comparisons) with 2243 CP, 824 AP, 615 PI, 795 healthy peri-implant, and 3575 healthy controls were considered for the TNF-α (G-308A) polymorphism in this meta-analysis. Variant A of TNF-α (G-308A) was associated with increased AP risk in the general population, especially in Asians, and this polymorphism was significantly associated with elevated risk of CP in Asians and Caucasians. There was no association between the A allele and PI risk. None of the contrasts of the genetic model yielded a significant finding in Latin Americans. Different genotyping methods may affect the association between the TNF-α (G-308A) polymorphism and these diseases.

CONCLUSION

These findings supported that variant A of the TNF-α (G-308A) polymorphism may contribute to CP and AP susceptibility, particularly in Asians and Caucasians. More efforts and further studies with larger sample sizes will be required to validate the risk of CP, AP, and PI.

Clinical and biochemical evaluation of oral irrigation in patients with peri-implant mucositis: a randomized clinical trial

OBJECTIVE

This randomized clinical trial aimed to compare the efficacy of an oral irrigator and an interdental brush in patients with peri-implant mucositis clinically and biochemically at different time points (at baseline and at the 2nd, 4th, and 12th weeks).

MATERIALS AND METHODS

Forty-five patients with at least one implant with peri-implant mucositis were included in the present study (n = 45). The patients were divided into three groups: oral irrigator + toothbrush (OI group, n = 15), interdental brush + toothbrush (IB group, n = 15), and toothbrush only (control) (C group, n = 15). The modified plaque index (mPlI), modified sulcus bleeding index (mSBI), probing pocket depth (PPD), probing attachment level (PAL), and bleeding on probing (BOP) were recorded at baseline and at the 2nd, 4th, and 12th weeks. The levels of interleukin 1 beta (IL-1β), transforming growth factor-beta (TGF-β), tissue-type plasminogen activator (t-PA), and plasminogen activator inhibitor-1 (PAI-1) were also determined in the peri-implant crevicular fluid samples biochemically.

RESULTS

The mSBI and t-PA at the 2nd week (p = 0.003; p = 0.003); the mPlI, mSBI, BOP, t-PA, and PAI-1 at the 4th week (p < 0.05; p < 0.001; p < 0.001; p = 0.015; p = 0.011); and the mPlI, mSBI, IL-1β, t-PA, and PAI-1 at the 12th week (p < 0.05; p < 0.001; p = 0.013; p < 0.001; p = 0.002) were significantly lower in the OI group compared with those in the C group. Meanwhile, PAI-1 at the 2nd week, mSBI at the 4th week, and t-PA at the 12th week were significantly lower in the OI group compared with those in the IB group (p < 0.001; p = 0.011; p = 0.003). At the 2nd, 4th, and 12th weeks, all other parameters were not statistically different in the three groups.

CONCLUSION

The clinical indexes (such as mSBI and BOP) that play an important role in the diagnosis of peri-implant mucositis showed the lowest means (although limited) in the OI group at all evaluation time points. Moreover, when the clinical and biochemistry results were interpreted altogether, it became apparent that the OI group exhibited similar or more effective results than the IB group in resolving peri-implant mucositis. In light of the foregoing, this study concluded that the use of an oral irrigator can be as effective as an interdental brush in interdental cleaning.

CLINICAL RELEVANCE

In this study, it is suggested that the regular use of an oral irrigator along with a toothbrush could be an appropriate alternative to other oral hygiene products such as dental floss and interdental brush for the management of peri-implant mucositis by preventing the accumulation of dental plaque (NCT03844035).

Expression of matrix metalloproteinases 2 and 9 in replanted teeth with external root resorption: A cross-sectional study

OBJECTIVE

To evaluate matrix metalloproteinase (MMP) expression in replanted permanent teeth with external root resorption (ERR).

DESIGN

The present cross-sectional study included 42 patients with replanted permanent teeth, presenting with progressive forms of ERR, and referred for extraction according to the rehabilitation treatment plan or due to root fractures. The control group consisted of 12 healthy premolars, from 5 patients with good periodontal health and no radiographic evidence of root resorption, referred for extraction for orthodontic reasons. Root fragments were processed soon after extraction, and the supernatant was collected to measure matrix metalloproteinase 2/tissue inhibitor of metalloproteinase 2 (MMP-2/TIMP-2) and matrix metalloproteinase 9/tissue inhibitor of metalloproteinases 2 (MMP-9/TIMP-2) complexes through a double-ligand enzyme-linked immunosorbent assay (ELISA).

RESULTS

Case groups with external inflammatory root resorption (EIRR) or external replacement root resorption (ERRR) showed significantly higher levels of MMP-2/TIMP-2 and MMP-9/TIMP-2 complexes than the control group. Additionally, comparisons between the case groups demonstrated that the MMP-2/TIMP-2 complex also had significantly higher levels in the ERRR group (p < 0.001).

CONCLUSIONS

Our results suggest that MMP-2 and MMP-9 participate in the pathobiology of both types of ERR. In addition, the higher levels of MMP-2/TIMP-2 complex in the ERRR group support common modulation mechanisms with physiological bone turnover.

Assessment of IL-10, IL-1ß and TNF-α gene polymorphisms in patients with peri-implantitis and healthy controls

Peri-implantitis (PI) is a multifactorial condition caused by the interactions of pathogens and the host immune response. Previous studies have demonstrated a relationship between PI and specific gene polymorphisms, particularly cytokine genes involved in the pathogenesis of PI. This study aimed to evaluate the frequency of single nucleotide polymorphisms (SNPs) of interleukin-10 (IL-10), interleukin 1ß (IL-1ß), and tumor necrosis factor-α (TNF-α) genes in PI patients and healthy controls. A total of 50 patients with PI and 89 periodontally healthy controls were recruited for this study. Venous blood samples (5 cc) were collected, and DNA was extracted. After DNA purification, the relevant gene segments were amplified by polymerase chain reaction (PCR). Restriction fragment length polymorphism (RFLP) and electrophoresis were performed to assess the polymorphisms of the related genes. The analysis revealed that allele and genotype frequencies of IL-10 ─ 819 C/T, IL-10 ─ 592 C/A, and IL-1ß + 3954 C/T significantly differed between PI patients and healthy controls. The analysis revealed no significant association between TNF-α ─ 857 G/A and TNF-α ─ 308 G/A polymorphisms and PI. Our results indicated that specific gene polymorphisms of IL-10 ─ 819 C/T, IL-10 ─ 592 C/A, and IL-1ß + 3954 C/T may play a role in the pathogenesis of PI, and increase its risk of occurrence.

Biomarker levels in peri-implant crevicular fluid of healthy implants, untreated and non-surgically treated implants with peri-implantitis

AIM

To compare biomarker levels in peri-implant crevicular fluid (PICF) of healthy implants with levels in PICF of implants with peri-implantitis (before and after non-surgical treatment).

MATERIALS AND METHODS

Samples were taken from 20 healthy implants (n = 17 patients) and from 20 implants with peri-implantitis (n = 19 patients) before and 3 months after non-surgical treatment using the Airflow Master Piezon^® (EMS). A Luminex™ assay was used to evaluate pro-inflammatory and anti-inflammatory cytokines IL-1β, TNF-α, IL-6 and G-CSF, collagen degradation enzyme MMP-8, chemokines MCP-1 & MIP-1α/CCL3, bone markers OPG and sRANKL and interferon-γ. Clinical and radiographical characteristics were assessed. A Mann-Whitney U and Wilcoxon signed-rank test analysed between- and within-group differences.

RESULTS

IL-1β and MMP-8 levels were found significantly elevated in implants with peri-implantitis (p = .007; p = <.001, respectively). No difference in levels of TNF-α, IL-6, MCP-1 and MIP-1α/CCL3, OPG and G-CSF between healthy and diseased implants was found. Levels of sRANKL and INF-γ were under the level of detection. None of the biomarker levels improved after non-surgical therapy, and levels of IL-1β and MMP-8 remained high.

CONCLUSION

Implants diagnosed with peri-implantitis have higher levels of IL-1β and MMP-8 in PICF compared to healthy implants. Non-surgical therapy did not influence the inflammatory immune response.

Evaluation of peri-implant tissues condition after 10-15 years of loading in treated chronic periodontitis patients attending a private practice setting: A retrospective study

OBJECTIVES

To retrospectively evaluate the conditions of the peri-implant tissues in treated patients with chronic periodontitis (CP) and in patients without chronic periodontitis (noCP).

MATERIALS AND METHODS

A chart review was used to evaluate 267 implants, 134 placed in 42 CP treated patients and 133 placed in 46 noCP patients. The primary outcome was to evaluate the condition of the peri-implant tissues (health, peri-mucositis, and peri-implantitis). The secondary outcome was to evaluate the possible association of some variables, such as, Plaque Index (PI), Bleeding Index (BI), probing pocket depth (PD), bleeding on probing (BoP), bone level (BL), loading time, type of implant placement and loading protocol, type of prosthesis, type of bone, implant manufacturer, and implant diameter and length, with the implant health condition.

RESULTS

The analysis of patient files revealed that after 10-15 years of loading (mean loading time 13.4 ± 2.07 years), six noCP patients (13%) experienced implant loss with a total of nine implants (6.7%) lost. The remaining 124 implants were classified: 54 (43.5%) as healthy, 45 (36.3%) with peri-implant mucositis, and 25 (20.2%) with peri-implantitis. Twelve CP subjects (28.5%) experienced implant loss with a total of 19 implants (14.1%) lost. The remaining 115 implants were classified: 34 (29.5%) as healthy, 40 (34.7%) with peri-implant mucositis and 41 (35.6%) with peri-implantitis. Compared with noCP subjects, only treated CP subjects with recurrent periodontal disease (RPD) showed differences statistically significant (p < .05).

CONCLUSIONS

After 10-15 years of loading, in CP patients treated in a private practice setting, most implants (70.1%) were classified with some type of peri-implant inflammation. In patients with RPD, a higher tendency for implant loss and peri-implant biologic complications was found.

Hyaluronic acid reduces inflammation and crevicular fluid IL-1β concentrations in peri-implantitis: a randomized controlled clinical trial

Purpose

This study investigated the effects of hyaluronic acid (HA) on peri-implant clinical variables and crevicular concentrations of the proinflammatory biomarkers interleukin (IL)-1β and tumor necrosis factor (TNF)-α in patients with peri-implantitis.

Methods

A randomized controlled trial was conducted in peri-implantitis patients. Patients were randomized to receive a 0.8% HA gel (test group), an excipient-based gel (control group 1), or no gel (control group 2). Clinical periodontal variables and marginal bone loss after 0, 45, and 90 days of treatment were assessed. IL-1β and TNF-α levels in crevicular fluid were measured by enzyme-linked immunosorbent assays at baseline and after 45 days of treatment. Clustering analysis was performed, considering the possibility of multiple implants in a single patient.

Results

Sixty-one patients with 100 dental implants were assigned to the test group, control group 1, or control group 2. Probing pocket depth (PPD) was significantly lower in the test group than in both control groups at 45 days (control 1: 95% CI, −1.66, −0.40 mm; control 2: 95% CI, −1.07, −0.01 mm) and 90 days (control 1: 95% CI, −1.72, −0.54 mm; control 2: 95% CI, −1.13, −0.15 mm). There was a trend towards less bleeding on probing in the test group than in control group 2 at 90 days (P=0.07). Implants with a PPD ≥5 mm showed higher levels of IL-1β in the control group 2 at 45 days than in the test group (P=0.04).

Conclusions

This study demonstrates for the first time that the topical application of a HA gel in the peri-implant pocket and around implants with peri-implantitis may reduce inflammation and crevicular fluid IL-1β levels.

Trial Registration

ClinicalTrials.gov Identifier: NCT03157193

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.

microRNAs in inflammatory alveolar bone defect: A review

Inflammatory alveolar bone defects are caused by periodontal pathogens, are one of the most common oral diseases in the clinic, and are characterized by periodontal support tissue damage. MicroRNAs (miRNAs) can participate in a variety of inflammatory lesions and modulate bone metabolism through the posttranscriptional regulation of target genes. In recent years, studies have confirmed that some miRNAs play significant roles in the development of inflammatory alveolar bone defects. Therefore, we reviewed the correlation between miRNAs and inflammatory alveolar bone defects and elucidated the underlying mechanisms to provide new ideas for the prevention and treatment of inflammatory alveolar bone defects.

Titanium Corrosion in Peri-Implantitis

Titanium (Ti) corrodes clinically in the presence of bacteria. We investigated this phenomenon as a function of Ti particles found in biopsied tissues around peri-implantitis sites and surface roughness of failed Ti implants. Tissue biopsies were surgically collected from peri-implantitis sites, processed, and embedded in resin. The resin-embedded samples were hand trimmed to the region of interest and semi-thick (500 nm) sections were collected onto coverslips. One section was toluidine blue post-stained as a reference. The remainder sections were left unstained for energy-dispersive X-ray spectroscopy (EDX) analysis. Processed samples were examined under scanning electron microscopy (SEM) and EDX. Corresponding failed implants were also removed and examined under SEM and EDX. Five out of eight biopsied samples demonstrated the presence of Ti particles in the soft tissue, suggesting the true rate among all failures was between 24.5% and 91.5% (the lower bound of a 95% confidence interval for the true rate of Ti presence). SEM analysis of failed implant bodies also indicated changes in surface morphology and appeared less detailed with decreased weight percent of Ti on the surface of the failed implants. In conclusion, Ti particles were noted in 5/8 biopsied samples. Surface morphologies were smoother in failed implants compared with the reference implant.

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.

Influence of occlusal loading on peri-implant inflammatory cytokines in crevicular fluid: a prospective longitudinal study

Objective

The objective of the study was to evaluate the relation between occlusal loading and peri-implant crevicular fluid cytokine expression in patients with implant-supported complete fixed prostheses in both arches.

Material and methods

A prospective longitudinal clinical study was performed at a university clinic. Fifteen patients were selected and 11 were included. All patients had bimaxillary implant-supported complete fixed ceramo-metallic prostheses loaded at least 12 months before the beginning of the study. Allocation was established for each patient using a computerized occlusal analysis system. The test implant was the maxillary implant closest to the point of highest occlusal loading. The maxillary implant with least loading was the control implant. Occlusal adjustment was performed using a round diamond burr. This occlusal distribution was verified with the occlusal analysis system. Expression of cytokines from peri-implant crevicular fluid (TNF-α, IL-10, IL-6, IL-1β, IL-8) were recorded and analyzed in both test and control implants before (baseline: T0) and 2 (T1) and 12 months (T2) after occlusal adjustment. The Brunner-Langer non-parametric test was performed.

Results

At T0, the expression of IL-10 was significantly higher in the test group implants (p = 0.018). Between T0 and T1, the expression of all the cytokines decreased in the implants of both groups with statistically significant differences, except for TNF (p = 0.271). When comparing both groups at T1, there was no statistically significant difference in any of the analyzed cytokines. At T2, TNF-α suffered when compared with baseline, a statistical decrease in both study and control implants (p < 0,001). At T2, there were no statistically significant differences between groups in any of the cytokines analyzed.

Conclusions

Implants with higher occlusal load presented higher expression of IL-10 in peri-implant crevicular fluid. Occlusal adjustment produced a decrease in the expression of all the analyzed cytokines, both in test and control implants.

Microbiological Profile and Human Immune Response Associated with Peri-Implantitis: A Systematic Review

PURPOSE

To evaluate and synthesize the existing evidence on the microbiological and human immune response associated with peri-implantitis in comparison to healthy implants.

MATERIALS AND METHODS

Three electronic databases (MEDLINE, Embase, and Cochrane Library) were searched in October 2019 to identify clinical studies evaluating the microbiota and the immune response associated with peri-implantitis. Two reviewers independently screened the studies and used the full text to extract the data. A qualitative synthesis was performed on the extracted data and summary tables were prepared. Due to clinical and methodological heterogeneity among included studies, no meta-analysis was performed.

RESULTS

Forty studies were included in this review. Of these, 20 studies compared the microbiological profile of peri-implantitis with healthy implants. Nineteen studies focused on the immune response associated with peri-implantitis in comparison to healthy implants. Three studies focus on gene polymorphism associated with peri-implantitis. The most commonly reported bacteria associated with peri-implantitis were obligate anaerobe Gram-negative bacteria (OAGNB), asaccharolytic anaerobic Gram-positive rods (AAGPRs), and other Gram-positive species. In regard to immune response, the most frequently reported pro-inflammatory mediators associated with peri-implantitis were IL-1β, IL-6, IL-17, TNF-α. Osteolytic mediator, e.g., RANK, RANKL, Wnt5a and proteinase enzymes, MMP-2, MMP-9, and Cathepsin-K were also expressed at higher level in peri-implantitis sites compared to control.

CONCLUSIONS

Peri-implantitis is associated with complex and different microbiota than healthy implants including bacteria, archaea, fungi, and virus. This difference in the microbiota could provoke higher inflammatory response and osteolytic activity. All of this could contribute to the physiopathology of peri-implantitis.

Strategies to Reduce Biofilm Formation in PEEK Materials Applied to Implant Dentistry-A Comprehensive Review

Polyether-ether-ketone (PEEK) has emerged in Implant Dentistry with a series of short-time applications and as a promising material to substitute definitive dental implants. Several strategies have been investigated to diminish biofilm formation on the PEEK surface aiming to decrease the possibility of related infections. Therefore, a comprehensive review was carried out in order to compare PEEK with materials widely used nowadays in Implant Dentistry, such as titanium and zirconia, placing emphasis on studies investigating its ability to grant or prevent biofilm formation. Most studies failed to reveal significant antimicrobial activity in pure PEEK, while several studies described new strategies to reduce biofilm formation and bacterial colonization on this material. Those include the PEEK sulfonation process, incorporation of therapeutic and bioactive agents in PEEK matrix or on PEEK surface, PEEK coatings and incorporation of reinforcement agents, in order to produce nanocomposites or blends. The two most analyzed surface properties were contact angle and roughness, while the most studied bacteria were Escherichia coli and Staphylococcus aureus. Despite PEEK's susceptibility to biofilm formation, a great number of strategies discussed in this study were able to improve its antibiofilm and antimicrobial properties.

Bone loss around implants-is it metallosis?

Most would agree that the etiology of dental implant failure is related to oral biofilm. At present one group of scientists and clinicians feel that biofilm is solely responsible for bone loss around the devices. However, there is strong evidence that particles and ions of titanium released into the surrounding tissues by the action of biofilm and/or mechanical forces, a process termed metallosis, can be responsible for bone loss around some dental implants. These findings are reinforced by similar responses found around failed metal on metal joint prostheses. Both possible etiologies are discussed in detail in this commentary.

Soft tissue healing around platform-switching and platform-matching single implants: A randomized clinical trial

BACKGROUND

Implants with platform-switching (PS) design have been demonstrated to reduce marginal bone loss. However, the influence on peri-implant soft tissue healing is unclear. This study was designed to investigate its effect on peri-implant soft tissue healing after implant uncovery.

METHODS

Non-smokers needing two implants in different quadrants were recruited in this study. For each individual, one PS and one platform-matching (PM) implants were placed using two-stage protocol. Following 2 to 8 months of healing, all implants were uncovered and connected to the corresponding healing abutments. Clinical measurements and peri-implant crevicular fluid (PICF) were taken at 1-, 2-, 4-, and 6-week after 2nd stage surgery. The cytokine concentrations in PICF were analyzed. Peri-implant mucosa (1 × 2 × 2 mm) was harvested around the healing abutment for the analysis of gene expression at uncovery and 6-week post-uncovery.

RESULTS

Eighteen participants (nine males; 51.7 ± 14.9 years) were recruited. Compared to PM, PS showed significantly lower probing depth (PD) at 1- and 2-week as well as modified sulcus bleeding index (mSBI) at 1-, 4-, and 6-week (P < 0.05). Over time, a decrease in osteoprotegerin and interleukin-1β concentrations in PICF along with an increase in receptor activator of unclear factor kappa-B ligand, periostin, and peroxidasin gene expressions in peri-implant mucosa were noted within both groups (P < 0.05) without significant intergroup differences.

CONCLUSION

Within the limits, implants with PS design rendered significant benefits over PM design in PD and mSBI reduction during a 6-week healing. However, molecular changes within PICF and peri-implant mucosa as a response to PM and PS appear negligible.

Peri-Implantitis Diagnosis and Prognosis Using Biomarkers in Peri-Implant Crevicular Fluid: A Narrative Review

Dental implant diseases, peri-implantitis (PI) and peri-implant mucositis (PIM), have shown wide prevalence in recent studies. Despite the prevalence, diagnosing peri-implant disease (PID) remains challenging as common diagnostic methods of periodontal probing and radiographs may be inaccurate. These methods only document pre-existing destruction rather than current disease activity. Furthermore, there is no current model to predict the progression of PID. Though a predictive model is lacking, biomarkers may offer some potential. Biomarkers are commonly used in medicine to objectively determine disease state, or responses to a therapeutic intervention. Gingival crevicular fluid (GCF) biomarkers have moderate diagnostic validity in periodontitis. Biomarkers in peri-implant crevicular fluid (PICF) also show promising results in regard to their diagnostic and prognostic value. The aim of this review is to summarize the current knowledge of PICF biomarkers in the diagnosis of PID and evaluate their validity to predict disease progression. This review found that PICF studies utilize different methods of sampling and interpretation with varying validity (sensitivity and specificity). A number of promising diagnostic techniques were identified. Commercially available chair-side tests for MMP-8 to diagnose periodontal disease and PID activity are now available. Future directions include proteomics and metabolomics for accurate, site-specific diagnosis and prediction of PID progression. Although more research is needed, this review concludes that the assessment of proinflammatory cytokines (IL-1β, TNFα, MMP-8) in the PICF may be of value to diagnose PI and PIM but current research remains insufficient to indicate whether biomarkers predict peri-implant disease progression.

Molecular tools for preventing and improving diagnosis of peri-implant diseases

Peri-implantitis is an inflammatory disease of tissues surrounding osseointegrated dental implants. Inflammation affecting soft and hard peri-implant tissues can cause alveolar bone resorption and subsequent implant loss. Clinical surveillance and early diagnosis are of paramount importance to reduce clinical failures and improve implant survival. Current diagnosis of implants is based on clinical and radiological signs. Molecular tests are an emerging diagnostic methodology, which potentially can help to detect and prevent early peri-implantitis and monitor the efficacy of therapy as well. A plethora of potential biomarkers are potentially available to support the clinical diagnosis of peri-implantitis. However, conflicting diagnostic conclusions have been reached, probably related to weak statistical results due to limited sample size or disease heterogeneity. The present paper reviews candidate diagnostic biomarkers for peri-implantitis, including infective agents, genetic susceptibility factors, and key proteins related to inflammation and tissue remodeling.

Peri-implantitis

OBJECTIVES

This narrative review provides an evidence-based overview on peri-implantitis for the 2017 World Workshop on the Classification of Periodontal and Peri-Implant Diseases and Conditions.

METHODS

A literature review was conducted addressing the following topics: 1) definition of peri-implantitis; 2) conversion from peri-implant mucositis to peri-implantitis, 3) onset and pattern of disease progression, 4) characteristics of peri-implantitis, 5) risk factors/indicators for peri-implantitis, and 6) progressive crestal bone loss in the absence of soft tissue inflammation.

CONCLUSIONS

1)Peri-implantitis is a pathological condition occurring in tissues around dental implants, characterized by inflammation in the peri-implant connective tissue and progressive loss of supporting bone. 2)The histopathologic and clinical conditions leading to the conversion from peri-implant mucositis to peri-implantitis are not completely understood. 3)The onset of peri-implantitis may occur early during follow-up and the disease progresses in a non-linear and accelerating pattern. 4a)Peri-implantitis sites exhibit clinical signs of inflammation and increased probing depths compared to baseline measurements. 4b)At the histologic level, compared to periodontitis sites, peri-implantitis sites often have larger inflammatory lesions. 4c)Surgical entry at peri-implantitis sites often reveals a circumferential pattern of bone loss. 5a)There is strong evidence that there is an increased risk of developing peri-implantitis in patients who have a history of chronic periodontitis, poor plaque control skills, and no regular maintenance care after implant therapy. Data identifying "smoking" and "diabetes" as potential risk factors/indicators for peri-implantitis are inconclusive. 5b)There is some limited evidence linking peri-implantitis to other factors such as: post-restorative presence of submucosal cement, lack of peri-implant keratinized mucosa and positioning of implants that make it difficult to perform oral hygiene and maintenance. 6)Evidence suggests that progressive crestal bone loss around implants in the absence of clinical signs of soft tissue inflammation is a rare event.

Peri-implantitis

OBJECTIVES

This narrative review provides an evidence-based overview on peri-implantitis for the 2017 World Workshop on the Classification of Periodontal and Peri-Implant Diseases and Conditions.

METHODS

A literature review was conducted addressing the following topics: 1) definition of peri-implantitis; 2) conversion from peri-implant mucositis to peri-implantitis, 3) onset and pattern of disease progression, 4) characteristics of peri-implantitis, 5) risk factors/indicators for peri-implantitis, and 6) progressive crestal bone loss in the absence of soft tissue inflammation.

CONCLUSIONS

1)Peri-implantitis is a pathological condition occurring in tissues around dental implants, characterized by inflammation in the peri-implant connective tissue and progressive loss of supporting bone. 2)The histopathologic and clinical conditions leading to the conversion from peri-implant mucositis to peri-implantitis are not completely understood. 3)The onset of peri-implantitis may occur early during follow-up and the disease progresses in a non-linear and accelerating pattern. 4a)Peri-implantitis sites exhibit clinical signs of inflammation and increased probing depths compared to baseline measurements. 4b)At the histologic level, compared to periodontitis sites, peri-implantitis sites often have larger inflammatory lesions. 4c)Surgical entry at peri-implantitis sites often reveals a circumferential pattern of bone loss. 5a)There is strong evidence that there is an increased risk of developing peri-implantitis in patients who have a history of chronic periodontitis, poor plaque control skills, and no regular maintenance care after implant therapy. Data identifying "smoking" and "diabetes" as potential risk factors/indicators for peri-implantitis are inconclusive. 5b)There is some limited evidence linking peri-implantitis to other factors such as: post-restorative presence of submucosal cement, lack of peri-implant keratinized mucosa and positioning of implants that make it difficult to perform oral hygiene and maintenance. 6)Evidence suggests that progressive crestal bone loss around implants in the absence of clinical signs of soft tissue inflammation is a rare event.

Host response and peri-implantitis

Considering the absence of predictable and effective therapeutic interventions for the treatment of peri-implantitis, scientific evidence concerning the host response profile around dental implants could be important for providing in the future a wider preventive and/or therapeutic window for this peri-implant lesion, indicating biomarkers that provide quantifiable measure of response to peri-implant therapy. Moreover, a better knowledge of pattern of host osteo-immunoinflammatory modulation in the presence of peri-implantitis could either benefit the early diagnostic of the disease or to cooperate to prognostic information related to the status of the peri-implant breakdown. Finally, new evidences concerning the host profile of modulators of inflammation and of osseous tissue metabolism around dental implants could explain the individual susceptibility for developing peri-implant lesions, identifying individuals or sites with increased risk for peri-implantitis. The focus of this chapter was, based on a systematically searched and critically reviewed literature, summarizing the existing knowledge in the scientific research concerning the host osteo-immunoinflammatory response to the microbiological challenge related to periimplantitis.

Mapping of inflammatory biomarkers in the peri-implant crevicular fluid before and after the occlusal loading of narrow diameter implants

OBJECTIVE

To monitor the cytokine release patterns in the peri-implant crevicular fluid (PICF) and to investigate which factors affect the success rate of narrow diameter implants (NDI) during the first year.

MATERIAL AND METHODS

Mandibular implant overdentures (IOD) retained by 2 NDI were installed in 16 clinically atrophic edentulous patients. The following parameters were monitored during the first year: (i) peri-implant health parameters (plaque index (PI), calculus presence (CP), gingival index (GI), probing depth (PD) and bleeding on probing (BoP); (ii) cytokine concentrations in the PICF (TNF-α, IL-1β, IL-6, IL-10); (iii) implant stability quotient (ISQ); (iv) marginal bone level (MBL) and bone level change (BLC); (v) implant success. The insertion torque, bone type, mandibular atrophy, time since edentulism, and smoking habits were also recorded. All data were analyzed using multivariable multilevel mixed-effects regression models.

RESULTS

The variability in the TNF-α release patterns temporarily reduced at weeks (w) 8-12, while the IL-1β concentrations remained low until they peaked at w48 [p < 0.05; + 177.55 pg/μl (+ 96.13 - + 258.97)]. Conversely, IL-10 release decreased significantly at w48 [p < 0.05; - 456.24 pg/μl (- 644.41 - - 268.07)]. The PD and ISQ decreased significantly (p < 0.05) over the follow-up period, while the MBL was stable after w48 with a BLC of 0.12 ± 0.71 mm. The overall success rate was 81.3%, and was influenced by TNF-α, IL-1β, IL-10, PI, GI, PD, smoking, and time since edentulism.

CONCLUSION

Pro- and anti-inflammatory cytokine release was balanced during the first 24 weeks. The GI, smoking, and time since edentulism are the most important factors determining the implant success.

CLINICAL RELEVANCE

The study contributes to the understanding of the osseointegration process in a clinically atrophic population rehabilitated with IOD, and highlights the importance of monitoring clinical peri-implant health-related parameters, smoking habit, and time since edentulism to predict implant success rates.

Influence of Insertion Torque on Clinical and Biological Outcomes before and after Loading of Mandibular Implant-Retained Overdentures in Atrophic Edentulous Mandibles

Aim

To evaluate the influence of primary insertion torque (IT) values of narrow dental implants on the peri-implant health, implant stability, immunoinflammatory responses, bone loss, and success and survival rates.

Methods

Thirty-one edentulous patients received two narrow implants (2.9x10mm, Facility NeoPoros) to retain mandibular overdentures. The implants were categorized in four groups according to their IT: (G1) IT > 10 Ncm; (G2) IT ≥ 10Ncm and ≤ 30 Ncm; (G3) IT >30Ncm and < 45Ncm; (G4) IT ≥ 45Ncm, and all implants were loaded after 3 months of healing. The following clinical outcomes were evaluated 1, 3, 6, and 12 months after implant insertion: (i) peri-implant tissue health (PH), gingival index (GI), plaque index (PI), calculus presence (CP), probing depth (PD), and bleeding on probing (BOP); (ii) implant stability quotient (ISQ) by resonance frequency analysis; and (iii) IL-1β and TNF-α concentration in the peri-implant crevicular fluid. The marginal bone level (MBL) and changes (MBC) were evaluated. The Chi² test, Kruskal-Wallis test, mixed-effects regression analysis, and the Kendall rank correlation coefficient were used for statistical analysis (α = 5%).

Results

G1 presented the highest PD at all evaluated periods. G2 presented higher PI at month 6 and 12. G4 showed increased GI at month 3 and 12 and more CP at month 1 (p=.003). G2 and G4 had higher ISQ values over the study period, while those from G1 and G3 presented lower ISQ values. The IL-1β concentration increased until month 12 and was independent of IT and bone type; G4 had a higher IL-1β concentration in month 3 than the other groups (p=.015). The TNF-α release was negatively correlated with IT, and TNF-α release was highest in G1 at month 12. The MBL immediately after surgery and the MBC at month 12 were similar between the groups, and G4 presented a positive MBC at month 12. The survival and success rates were 75% for G1, 81.3% for G2, 64.3% for G3, and 95% for G4.

Conclusion

The IT did not influence the clinical outcomes and the peri-implant immunoinflammatory responses and was weakly correlated with the narrow dental implants primary stability. The observed success rates suggest that the ideal IT for atrophic fully edentulous patients may deviate from the standardized IT of 32 Ncm.

The depth of the implant mucosal tunnel modifies the development and resolution of experimental peri-implant mucositis: A case-control study

Background

Resolution and prevention of peri‐implant mucositis are a key in preventing peri‐implantitis. This case–control study aims to assess the modifying effect of a deep mucosal tunnel (DMT) on the induction and resolution phases of experimental peri‐implant mucositis.

Methods

Nineteen subjects with a tissue level implant were assigned to cases (DMT, depth ≥3 mm) or controls (shallow mucosal tunnel ≤1 mm, SMT). Subjects underwent a standard experimental peri‐implant mucositis protocol characterized by an oral hygiene optimization phase, a 3‐week induction phase using an acrylic stent to prevent self‐performed oral hygiene at the experimental implant, and a 3 + 2 weeks resolution phase. Modified plaque (mPI), gingival index (mGI) and peri‐implant sulcus fluid IL‐1β concentrations were measured over time. Differences between DMT and SMT were assessed with the Mann–Whitney test.

Results

Modified plaque index and mGI increased in parallel during the induction phase. After resumption of oral hygiene practice, mPI and mGI resolved towards baseline values in the SMT group. In DMT, mPI and mGI values diverged: plaque resolved but resolution of inflammation was delayed and of smaller magnitude during the first 3 weeks after resumption of oral hygiene. IL‐1β concentrations were significantly higher in DMT at 21 days (end of induction) and during the resolution phase corroborating the clinical findings. Removal of the crown and submucosal professional cleaning were needed to revert mGI to baseline values in DMT implants.

Conclusions

The depth of the mucosal tunnel modifies the resolution of experimental peri‐implant mucositis at transmucosal implants. This observation raises important questions on the effectiveness of self‐performed oral hygiene in cases where implants are placed deeper and the ability to resolve mucositis and effectively prevent peri‐implantitis in such situations.