Peri-implant disease: what we know and what we need to know

Realizing the clinical utility of saliva for monitoring oral diseases

In the era of personalized/precision health care, additional effort is being expended to understand the biology and molecular mechanisms of disease processes. How these mechanisms are affected by individual genetics, environmental exposures, and behavioral choices will encompass an expanding role in the future of optimally preventing and treating diseases. Considering saliva as an important biological fluid for analysis to inform oral disease detection/description continues to expand. This review provides an overview of saliva as a diagnostic fluid and the features of various biomarkers that have been reported. We emphasize the use of salivary biomarkers in periodontitis and transport the reader through extant literature, gaps in knowledge, and a structured approach toward validating and determine the utility of biomarkers in periodontitis. A summation of the findings support the likelihood that a panel of biomarkers including both host molecules and specific microorganisms will be required to most effectively identify risk for early transition to disease, ongoing disease activity, progression, and likelihood of response to standard periodontal therapy. The goals would be to develop predictive algorithms that serve as adjunctive diagnostic tools which provide the clinician and patient important information for making informed clinical decisions.

Peri-implant diseases and systemic inflammation: A preliminary analysis from a cross-sectional survey of patients with hypertension

BACKGROUND

The aim of this study was to investigate the association between peri-implant diseases and systemic inflammation assessed by serum C-reactive protein (CRP) levels in a sample of patients with hypertension.

METHODS

A total of 151 participants with hypertension were included in a cross-sectional study. The population was divided into six groups according to their peri-implant and periodontal status (healthy controls, mucositis, peri-implantitis, periodontitis, periodontitis and mucositis, periodontitis, and peri-implantitis). Linear, logistic regression, and correlation analyses were performed.

RESULTS

CRP levels were statistically significantly higher in participants with periodontitis alone (median 3.2 mg/L, interquartile range [IQR] 1.8, p = 0.012), combined with mucositis (3.10 mg/L, IQR 2.35, p < 0.001) or peri-implantitis (2.7 mg/L, IQR 2.53, p = 0.002) when compared to the healthy controls (1 mg/L, IQR 1.2). This association was independent of age, sex, smoking status, and adiposity differences. Participants with periodontitis with and without peri-implant diseases had the greatest odds of exhibiting CRP > 3 mg/L (odds ratio = 7.3, 95% confidence interval 1.6-33.9).

CONCLUSIONS

Peri-implant diseases are associated with systemic inflammation, but the nature of the association should be further investigated.

Evaluation of salivary stress markers and inflammatory cytokine levels in peri-implantitis patients

BACKGROUND AND OBJECTIVE

Psychological stress has been identified in some observational studies as a potential factor that may modify and affect periodontal diseases, but there are no similar data for peri-implantitis. The aim of this study was to determine the relationship between interleukin (IL)-1β, IL-6, IL-10, interferon (IFN)α inflammatory cytokines and the psychological stress-related markers, glucocorticoid receptor-α (GRα), and salivary α-amylase (sAA) gene expression levels in saliva samples obtained from healthy implants and peri-implantitis patients.

MATERIALS AND METHODS

The study included a total of 50 systemically healthy subjects. Peri-implant clinical parameters were recorded and psychological stress level was evaluated with the hospital anxiety and depression scale (HAD) and state-trait anxiety inventory (STAI) questionnaire forms. Following the evaluations, the patients were divided into 4 groups according their stress and clinical status (Ia, Ib, IIa, IIb). IL-1β, IL-6, IL-10, IFNα, GRα, sAA gene expression levels in the saliva samples were quantified by quantitative polymerase chain reaction (qPCR).

RESULTS

In the group of peri-implantitis who had a high score in stress level assessment scales, significantly higher IL-1β, IL-6, sAA expression levels were observed (p < 0.001). The IL-10 gene expression levels were lower in the groups with a high score in the stress level assessment scales (p < 0.001). GRα gene was expressed at lower levels in the group of peri-implantitis who had a high score in stress level assessment scales but the difference was not statistically significant (p = 0.065).

CONCLUSION

The study findings suggest that psychological stress may increase the inflammation associated with peri-implantitis by affecting cytokine expression levels.

CLINICAL RELEVANCE

To prevent peri-implantitis or reduce its prevalence, it could be beneficial to evaluate stress levels and identify individuals experiencing stress.

The effect of individuals' oral hygiene habits and knowledge levels on peri-implant health and disease: a questionnaire-based observational study

BACKGROUND

Peri-implant disease and health are associated with microbial dental plaque. Therefore, oral hygiene plays a role in preventing and treating these diseases. This study aimed to determine the relationships among knowledge of peri-implant status, oral hygiene habits, and peri-implant disease and health.

METHODS

A total of 144 implants in nonsmokers with controlled systemic disease were included in the study. Peri-implant disease and the conditions of the implants were determined with periodontal indices and radiographs based on the 2017 World Workshop on the Classification of Periodontal and Peri-implant Diseases and Conditions and The EFP S3 level clinical practice guideline. Individuals were asked 66 questions regarding demographic information, oral hygiene habits and history, and knowledge of peri-implant diseases. One-way ANOVA was used to compare the three peri-implant disease and condition categories.

RESULTS

There was a significant difference between groups regarding toothpaste type (p < 0.05). Gum protection toothpaste was greater in the peri-implant health group. Patients' use of interdental products was very low; often, no products were used for implant prosthesis. There was no significant difference among the groups regarding oral hygiene product use or oral hygiene habits (p > 0.05). There was a significant difference between groups regarding frequency of visit (p < 0.05). The frequency of visits to the dentist for pain was greater for individuals with peri-implantitis. There is a significant difference between the groups' answers for the causative and initiating factors of peri-implant disease (p < 0.05). The peri-implant health group answered that microbial dental plaque is the most crucial initiating factor of peri-implant diseases, and bleeding on probing is the most critical determinant of peri-implant diseases at a higher rate than the other groups.

CONCLUSIONS

Patients' oral hygiene habits and knowledge levels are almost similar according to peri-implant status. Knowledge does not reflect a patient's oral hygiene behavior. Clinicians should ensure that individuals' oral hygiene practices align with their increased awareness regarding peri-implant illnesses.

Clinical and Radiographic Outcomes of Adjunctive Phototherapy Versus Antibiotic Therapy Against Peri-Implant Diseases: A Systematic Review and Meta-Analysis

Background: Peri-implantitis, an inflammatory condition in implant tissues, requires bacterial eradication and implant surface decontamination, with aPDT as a helpful surgical adjunct. Objective:This project was designed to investigate the effect of antibiotic therapy versus aPDT, as adjuncts to conventional mechanical debridement (MD), on the peri-implant clinical and/or radiographic parameters among patients with peri-implant diseases. Methods: A comprehensive search was conducted across electronic databases, including PubMed, Scopus, and Web of Science, up to and including April 2023, without any restriction on the language and year of publication, focusing the following research question: "Does adjunctive aPDT improve the peri-implant clinical and/or radiographic parameters in treating peri-implant diseases compared to antibiotic therapy?" Statistical analysis was performed on peri-implant clinical [plaque index (PI), probing depth (PD), and bleeding on probing (BOP)] and radiographic parameters [marginal bone loss (MBL)]. The study included six randomized controlled trials and one clinical (nonrandomized) study. Results: The systematic review findings indicate that the application of aPDT as an adjunct to MD is equally effective as adjunctive antibiotic therapy in improving peri-implant clinical parameters and radiographic parameters in patients with peri-implant diseases. Only two studies were classified as having a low risk of bias (RoB), two were assessed as having an unclear RoB, and the remaining three studies were determined to have a high RoB. However, the meta-analysis results revealed no statistically significant difference in peri-implant PI, PD, and MBL scores between patients treated with adjunct aPDT or adjunct antibiotic therapy. Notably, there was a statistically significant difference favoring adjunct aPDT in peri-implant BOP values compared to the control group. Conclusions: Despite the limited number of included studies and the significant heterogeneity among them, the findings suggest that aPDT yields comparable peri-implant clinical and radiographic outcomes to adjunctive antibiotic therapy, as adjuncts to MD, for the potential treatment of peri-implant diseases.

The role of autophagy in SIM mediated anti-inflammatory osteoclastogenesis through NLRP3 signaling pathway

BACKGROUND

Inflammatory bone resorption is a prominent risk factor for implantation failure. Simvastatin (SIM) has anti-inflammatory effects independent of cholesterol lowering and reduces osteoclastogenesis by decreasing both the number and activity of osteoclasts. However, the specific mechanism of inflammatory bone loss alleviation by SIM remains to be elucidated. We hypothesized that SIM relieves inflammatory bone loss by modulating autophagy and suppressing the NOD-like receptor family pyrin domain-containing protein 3 (NLRP3) signaling pathway.

METHODS AND RESULTS

RAW264.7 cells were stimulated by lipopolysaccharide (LPS) after being pretreated with various concentrations of SIM. Osteoclast (OC) differentiation, formation and activity were evaluated by tartrate-resistant acid phosphatase staining, F-actin ring staining and bone resorption pit assays, respectively. We observed autophagosomes by transmission electron microscopy. Then NLRP3 inhibitor MCC950 was used to further explore the corresponding molecular mechanism underlying anti-inflammatory bone resorption, the expression of autophagy-related proteins and NLRP3 signaling pathway factors in pre-OCs were evaluated by western blot analysis, and the expression of OC-specific molecules was analyzed using reverse transcription-quantitative polymerase chain reaction. The results showed that SIM decreased the expression of tumor necrosis factor-α, whereas increased Interleukin-10. In addition, SIM inhibited LPS-induced OC differentiation, formation, bone resorption activity, the level of autophagosomes, and OC-specific markers. Furthermore, SIM significantly suppressed autophagy by downregulating LC3II, Beclin1, ATG7, and NLRP3-related proteins expression while upregulating P62 under inflammatory conditions.

CONCLUSIONS

SIM may reduce autophagy secretion to attenuate LPS-induced osteoclastogenesis and the NLRP3 signaling pathway participates in this process, thus providing theoretical basis for the application of this drug in peri-implantitis.

Utilization of Low-Magnitude High-Frequency Vibration (LMHFV) as an Aid in Treating Peri-Implantitis: Case Presentations

Peri-implantitis is an inflammatory process initiating in the soft tissue and then progressing to the hard tissue surrounding dental implants leading to loss of osseous support and potential loss of the implant if not identified early in the process. This process initiates in the soft tissue, which become inflamed spreading to the underlying bone leading to decreases in bone density with subsequent crestal resorption and thread exposure. In the absence of treatment of the peri-implantitis, the bone loss at the osseous implant interface progresses with inflammatory mediated decrease in the bone density that moves apically, eventually leading to mobility of the implant and its failure. Low-magnitude high-frequency vibration (LMHFV) has been shown to improve bone density, stimulate osteoblastic activity, and arrest progression of peri-implantitis with improvement of the bone or graft around the affected implant with or without surgery as part of the treatment. Two cases are presented using LMHFV to augment treatment.

Biodegradable and Cytocompatible Hydrogel Coating with Antibacterial Activity for the Prevention of Implant-Associated Infection

Implant-associated infection (IAI) caused by pathogens colonizing on the implant surface is a serious issue in the trauma-orthopedic surgery, which often leads to implant failure. The complications of IAI bring a big threat to the clinical practice of implants, accompanied by significant economic cost and long hospitalization time. In this study, we propose an antibiotics-free strategy to address IAI-related challenges by using a biodegradable and cytocompatible hydrogel coating. To achieve this, a novel hydrogel system was developed to combine the synergistic effects of good cell affinity and antibacterial properties. The hydrogel material was prepared by modifying a photocross-linkable gelatin-based polymer (GelMA) with cationic quaternary ammonium salt (QAS) groups via a mild and simple synthesis procedure. By engineering the length of the hydrophobic carbon chain on the QAS group and the degree of functionalization, the resulting GelMA-octylQAS hydrogel exhibited an integration of good mechanical properties, biodegradability, excellent bactericidal activity against various types of bacteria, and high cytocompatibility with mammalian cells. When coated onto the implant via the in situ cross-linking procedure, our hydrogel demonstrated superior antimicrobial ability in the infective model of femoral fracture of rats. Our results suggest that the GelMA-octylQAS hydrogel might provide a promising platform for preventing and treating IAI.

Non-Surgical Therapy and Oral Microbiota Features in Peri-Implant Complications: A Brief Narrative Review

The therapeutic discretion in cases of peri-implantitis should take into account the limits and advantages of specific therapeutic itineraries tailored according to each clinical case and each individual patient. This type of oral pathology emphasizes the complex classification and diagnostic issues coupled with the need for targeted treatments, in light of the oral peri-implant microbiota changes. This review highlights the current indications for the non-surgical treatment of peri-implantitis, describing the specific therapeutic efficacy of different approaches and discussing the more appropriate application of single non-invasive therapies The non-surgical treatment choice with antiseptics or antibiotics (single or combined, local, or systemic) for short courses should be considered on a case-by-case basis to minimize the incidence of side effects and concomitantly avoid disease progression.

Evaluation of red-complex bacteria loads in complete denture patients: a pilot study

OBJECTIVE

This pilot study aimed to evaluate red-complex bacteria (RCB) loads in edentulous patients, before and after dentures' insertion.

MATERIALS AND METHODS

Thirty patients were included in the study. Deoxyribonucleic acid (DNA) isolated from bacterial samples were obtained from the dorsum of the tongue before and 3 months after complete dentures (CDs) insertion in order to identify the presence of RCB (Tannerella forsythia, Porphyromonas gingivalis, and Treponema denticola) and quantify their loads, using real-time polymerase chain reaction (RT-PCR). Bacterial loads were represented as "Lg (genome equivalents/sample)" and the data classified according to the "ParodontoScreen" test.

RESULTS

Significant changes in bacterial loads were observed before and 3 months after the CDs insertion for: P. gingivalis (0.40 ± 0.90 vs 1.29 ± 1.64, p = 0.0007), T. forsythia (0.36 ±0.94 vs 0.87 ± 1.45, p = 0.005), and T. denticola (0.11 ± 0.41 vs 0.33 ± 0.75, p = 0.03). Before the CDs insertion, all patients had a normal bacterial prevalence range (100%) for all analyzed bacteria. Three months after the insertion, 2 (6.7%) of them had a moderate bacterial prevalence range for P. gingivalis, while 28 (93.3%) had a normal bacterial prevalence range.

CONCLUSION

The use of CDs has a significant impact on increasing RCB loads in edentulous patients.

Novel Dental Restorative Solutions for Natural Teeth and Implants

The long-term survival of restorations in the oral cavity has always been one of the most significant challenges in modern dental practice [...].

Antibacterial nanopatterned coatings for dental implants

Dental implants, usually made of titanium, are exposed to hostile oral microflora that facilitate bacterial infections and subsequent inflammation. To mitigate these processes, we coated titanium substrates with block copolymer nanopatterns and investigated the bactericidal effect of these coatings against Gram-positive and Gram-negative bacteria. We found that the bactericidal efficacy of the coatings depends on their morphology and surface chemistry as well as on the bacterial strain: an optimal combination can lead to significant bacterial death for a short time, i.e. 90% for 90 min. Human gingival fibroblasts in contact with the nanopatterned coatings showed similar cell attachment and morphology as on bare Ti. Immunostaining assays showed similar levels of CCR7 and CD206 in macrophages cultured over the nanopatterns and bare Ti, demonstrating adequate properties for tissue integration. The nanopatterns induced a small increase in macrophage aspect ratio, which might indicate early states of M2 polarization, given the absence of CD206.

Smoking Cessation on Periodontal and Peri-Implant Health Status: A Systematic Review

Since smoking is considered among the main risk factors for the onset and progression of periodontitis and peri-implantitis, the present systematic review aimed to evaluate the effect of smoking cessation on clinical, radiographic, and gingival crevicular periodontal parameters around natural teeth and dental implants in ex-smokers compared to current and non-smokers. The study protocol was developed based on the PRISMA guidelines, the research question was formulated according to the PICO model, and the literature search was conducted through PubMed/MEDLINE, Cochrane library, and BioMed Central databases. From the 916 title/abstracts initially identified, seven articles were included in the present systematic review and assessed for quality through the ROBINS-I tool. Reported findings on clinical and crevicular periodontal parameters around natural teeth were contrasting when comparing ex-smokers to current and non-smokers; thus, individualized recommendations for previous smoker periodontal patients are currently lacking. No data on radiographic parameters were retrieved. Similarly, data on periodontal parameters around dental implants were not available, highlighting the need for focused investigations assessing the role of both smoking habit and cessation on peri-implant health status and responsiveness to treatment.

The Antibacterial and Cytotoxic Effects of Silver Nanoparticles Coated Titanium Implants: A Narrative Review

Nanotechnology has become an emerging research field with numerous biomedical scientific applications. Silver possesses bactericidal activities that have been harnessed for centuries; however, there is a concern about the toxic effects of silver nanoparticles. This paper aims to provide an overview of silver-treated dental implants and discuss their potential to reduce the prevalence of peri-implant diseases. An electronic search was performed using PubMed. After screening, data extraction was performed on the 45 remaining articles using inclusion and exclusion criteria. Most of the articles demonstrated that silver nanoparticles embedded in a coating layer and/or on surface-treated titanium exhibit sound antibacterial effects and biocompatibility. Most of the reviewed studies revealed that silver nanoparticles on dental implant surfaces reduced cytotoxicity but provided a prolonged antibacterial effect. The cytotoxicity and antibacterial effect are closely linked to how the silver nanoparticles are released from the titanium surfaces, where a slower release increases cell viability and proliferation. However, to improve the clinical translation, there is still a need for more studies, especially evaluating the long-term systemic effects and studies recreating the conditions in the oral cavity.

Effect Morphology and Surface Treatment of the Abutments of Dental Implants on the Dimension and Health of Peri-Implant Biological Space

Statement of the problem: The gingival configuration around implant abutments is of paramount importance for preserving the underlying marginal bone, and hence for the long-term success of dental implants. Objective: The objective was to study, clinically and histologically, the effects of the change in the morphology of abutments connected to the endosseous implant, and of their surface treatment. In particular, the objective was to ascertain the effect of changing the shape of the transepithelial pillar and the treatment of its surface on the dimensions, quality and health of the components of the peri-implant biological space, such as the dimensions of the epithelial and connective tissues of the biological space, the concentration of inflammatory cells and the density of collagen fibers. Methods: A clinical trial of 10 patients with a totally edentulous maxilla, who had four implants (IPX4010_GALIMPLANT®, Sarria, Spain) inserted in the area of the first and second molars on both sides with computer-guided implant surgery, was conducted with the final purpose of assessing the quality of the peri-implant soft tissue attachment around the transepithelial abutments which were employed (aesthetic machined (RM), aesthetic anodized (RA), slim machined (SM) and slim anodized (SA)). At 8 weeks and following the collection of the samples (removal of the implant-abutment assembly with its surrounding hard and soft tissue) and their processing for subsequent histological and histomorphometric analysis in order to study the dimensions, quality and health of the peri-implant soft tissue area, the variables previously mentioned were determined according to the aims of the study. By using appropriate diameter trephine in order to obtain a useful fringe of soft tissue around the transepithelial pillars, ANOVA and chi-square tests were performed. Results: The SPSS statistical analysis ANOVA results revealed that the machined slim abutments have a better performance considering the variables analyzed with epithelial and connective attachment heights of 1.52 mm and 2.3 mm, respectively, and that connective density (density of collagen fibers) was high at 85.7% of the sample size affected by the design for the slim abutments and 92.9% of the high-density sample size affected by the surface treatment for the machined surface. Conclusions: All variables studied, despite the small sample size, showed the superiority of the slim machined abutment among the four groups.

Peri-Implantitis: Application of a Protocol for the Regeneration of Deep Osseous Defects. A Retrospective Case Series

Background and aims: Peri-implantitis is a complex pathology, both in its diagnosis and in the identification of etiological causes. Although we have been studying more and more over the years to try to answer the many questions that remain regarding everything that circulates around this disease which affects implants, nothing has yet been taken as an official consensus regarding its surgical treatment. There are still many proposed protocols, each of which has been shown to have comforting results and promising prospects, but no total predictability. The aim of this case series is to assess the clinical outcomes of a mixed protocol for the regeneration of deep osseous defects. Materials and methods: The data and clinical records of 23 patients, with 29 implants affected by peri-implantitis treated surgically in private practice, were analyzed retrospectively. The method used for the surgical treatment was a mixed protocol of mechanical–chemical decontamination and bone regeneration with bovine xenograft. Results: All patients were followed for at least 2 years, averaging 28.9 months (a range of 24–38 months) with a reduction in the probing depth (PD) at one year from the initial 8.14 ± 1.156 mm to 3.72 ± 0.649 mm, and to 4.14 ± 1.093 mm at the final assessment. The differences between assessment time points were always statistically significant. The data regarding bleeding on probing (BoP) and suppuration also showed a statistically significant reduction at the final time point compared to the baseline. Only one patient, at 24 months, still showed BoP, suppuration, and a PD deeper than 5 mm, indicating a recurrence of the disease compared to the initial improvement of the PD (5 mm) at one year. Conclusions: In conclusion, within the limits of this retrospective analysis, it can be affirmed that this combined mechanical–chemical and regenerative decontamination therapy is effective in the treatment of peri-implantitis.

The effects of physical decontamination methods on zirconia implant surfaces: a systematic review

PURPOSE

Peri-implantitis therapy and implant maintenance are fundamental practices to enhance the longevity of zirconia implants. However, the use of physical decontamination methods, including hand instruments, polishing devices, ultrasonic scalers, and laser systems, might damage the implant surfaces. The aim of this systematic review was to evaluate the effects of physical decontamination methods on zirconia implant surfaces.

METHODS

A systematic search was conducted using 5 electronic databases: Ovid MEDLINE, PubMed, Scopus, Web of Science, and Cochrane. Hand searching of the OpenGrey database, reference lists, and 6 selected dental journals was also performed to identify relevant studies satisfying the eligibility criteria.

RESULTS

Overall, 1049 unique studies were identified, of which 11 studies were deemed suitable for final review. Air-abrasive devices with glycine powder, prophylaxis cups, and ultrasonic scalers with non-metal tips were found to cause minimal to no damage to implant-grade zirconia surfaces. However, hand instruments and ultrasonic scalers with metal tips have the potential to cause major damage to zirconia surfaces. In terms of laser systems, diode lasers appear to be the most promising, as no surface alterations were reported following their use.

CONCLUSION

Air-abrasive devices and prophylaxis cups are safe for zirconia implant decontamination due to preservation of the implant surface integrity. In contrast, hand instruments and ultrasonic scalers with metal tips should be used with caution. Recommendations for the use of laser systems could not be fully established due to significant heterogeneity among included studies, but diode lasers may be the best-suited system. Further research-specifically, randomised controlled trials-would further confirm the effects of physical decontamination methods in a clinical setting.

Bioactive coatings for dental implants: A review of alternative strategies to prevent peri-implantitis induced by anaerobic bacteria

Members of oral bacterial communities form biofilms not only on tooth surfaces but also on the surface of dental implants that replace natural teeth. Prolonged interaction of host cells with biofilm-forming anaerobes frequently elicits peri-implantitis, a destructive inflammatory disease accompanied by alveolar bone loss leading to implant failure. Here we wish to overview how the deposition of bioactive peptides to dental implant surfaces could potentially inhibit bacterial colonization and the development of peri-implantisis. One preventive strategy is based on natural antimicrobial peptides (AMPs) immobilized on titanium surfaces. AMPs are capable to destroy both Gram positive and Gram negative bacteria directly. An alternative strategy aims at coating implant surfaces - especially the transmucosal part - with peptides facilitating the attachment of gingival epithelial cells and connective tissue cells. These cells produce AMPs and may form a soft tissue seal that prevents oral bacteria from accessing the apical part of the osseointegrated implant. Because a wide variety of titanium-bound peptides were studied in vitro, we wish to concentrate on bioactive peptides of human origin and some of their derivatives. Furthermore, special attention will be given to peptides effective under in vivo test conditions.

Levels of procalcitonin in saliva and peri-implant crevicular fluid in patients with peri-implant diseases and health

OBJECTIVE

To evaluate the levels of procalcitonin in saliva and peri-implant crevicular fluid (PICF) among healthy and peri-implant disease patients and correlate these levels with clinical and radiographic peri-implant parameters.

DESIGN

Three groups of 20 participants each [Group-1: healthy, Group-2: peri-implant mucositis, and Group-3: peri-implantitis] were selected. Peri-implant plaque index, bleeding on probing, probing depth and crestal bone loss was assessed. PICF and saliva samples were evaluated for procalcitonin levels and analyzed using enzyme-linked immunosorbent assay. Kruskal-Wallis test was performed for comparisons among the study groups. Multiple comparisons were considered for Post hoc two-group comparisons using Bonferroni-corrections. The Spearman rank correlation coefficient analysis was used to analyze the correlation between procalcitonin levels of both fluids and clinical peri-implant parameters.

RESULTS

Group-3 demonstrated significantly higher values for peri-implant plaque index, bleeding on probing, probing depth, and crestal bone loss as compared to Group-1 and Group-2. Participants of both Group-2 and Group-3 reported significantly increased procalcitonin levels in saliva and PICF in comparison to Group-1. Significant positive correlations were found between PICF procalcitonin levels and bleeding on probing, probing depth, and crestal bone loss in Group-3 and significant positive correlation was found between PICF and bleeding on probing in Group-2. For salivary procalcitonin levels, a significant positive correlation was observed between procalcitonin and bleeding on probing in Group-3.

CONCLUSIONS

The outcome of this study suggests that procalcitonin might play a role in peri-implant inflammation, and higher procalcitonin levels is suggestive of a probable surrogate biomarker for peri-implant diseases.

Matrix Metalloproteinase 9 is Regulated by LOX-1 and erk1/2 Pathway in Dental Peri-Implantitis

BACKGROUND AND OBJECTIVE

Dental peri-implantitis, which can be caused by several different microbial factors, is characterized by inflammatory lesions of the surrounding hard and soft tissues of an oral implant. Matrix Metalloproteinase 9 (MMP9) is thought to be involved in the pathogenesis of peri-implantitis. However, the regulatory mechanism of MMP9 in peri-implantitis has not been fully elucidated. In this study, we tried to evaluate the regulatory mechanism of MMP9 in peri-implantitis.

METHODS

We collected Peri-Implant Crevicular Fluid (PICF) from ten healthy implants and ten periimplantitis patients and compared their expression level of MMP9. We also cultured macrophages from the peripheral blood of healthy volunteers infected by Porphyromonas gingivalis to reveal the regulatory mechanism of MMP9 in peri-implantitis. Western blot, immunofluorescence staining and quantitative Polymerase Chain Reaction (RT-PCR) were used to better characterize the mechanism of MMP9.

RESULTS

The expression of MMP9 was up-regulated in peri-implantitis patient PICF and P. gingivalis infected human macrophages. LOX-1, not dectin-1, was found to mediate MMP9 expression in human macrophages with P. gingivalis infection. Expression of Erk1/2 was responsible for infection-induced MMP9 expression. Finally, use of a broad-spectrum metalloproteinase inhibitor impaired LOX-1 expression in infected macrophages.

CONCLUSION

Our results demonstrate that MMP9 is involved in dental peri-implantitis and is regulated by LOX-1 and Erk1/2. This LOX-1/MMP9 signaling pathway may represent a potential drug target for peri-implantitis.

Development of a Novel Medical Device for Mucositis and Peri-Implantitis Treatment

In spite of all the developments in dental implantology techniques, peri-implant diseases are frequent (prevalence up to 80% and 56% of subjects for mucositis and peri-implantitis, respectively) and there is an urgency for an effective treatment strategy. This paper presents an innovative electromedical device for the electromagnetic treatment of mucositis and peri-implantitis diseases. This device is also equipped with a measurement part for bioimpedance, which reflects the health conditions of a tissue, thus allowing clinicians to objectively detect impaired areas and to monitor the severity of the disease, evaluate the treatment efficacy, and adjust it accordingly. The design of the device was realized considering literature data, clinical evidence, numerical simulation results, and electromagnetic compatibility (EMC) pre-compliance tests, involving both clinicians and engineers, to better understand all the needs and translate them into design requirements. The reported system is being tested in more than 50 dental offices since 2019, providing efficient treatments for mucositis and peri-implantitis, with success rates of approximately 98% and 80%, respectively.

Repeated Exposure of Nanostructured Titanium to Osteoblasts with Respect to Peri-Implantitis

Titanium offers excellent biocompatibility and extraordinary mechanical properties. As a result, it is used as a material for dental implants. Implants infected by peri-implantitis can be cleaned for successful re-osseointegration. Optimal surface properties, such as roughness and wettability, have a significant impact on cell adhesion. The aim of this study was to evaluate the adhesion and proliferation of osteoblasts on the surface of repeatedly cleaned nanostructured titanium samples. Human osteoblast-like cells MG-63 were seeded on nanostructured titanium specimens manufactured from rods produced by the equal channel angular pressing. For surface characterization, roughness and wettability were measured. Cell adhesion after 2 h as well as cell proliferation after 48 h from plating was assessed. We have found that this repeated cleaning of titanium surface reduced cell adhesion as well as proliferation. These events depend on interplay of surface properties, such as wettability, roughness and topography. It is difficult to distinguish which factors are responsible for these events and further investigations will be required. However, even after the several rounds of repeated cleaning, there was a certain rate of adhesion and proliferation recorded. Therefore the attempts to save failing implants by using in situ cleaning are promising.

Mitigation of peri-implantitis by rational design of bifunctional peptides with antimicrobial properties

The integration of molecular and cell biology with materials science has led to strategies to improve the interface between dental implants with the surrounding soft and hard tissues in order to replace missing teeth and restore mastication. More than 3 million implants have been placed in the US alone and this number is rising by 500,000/year. Peri-implantitis, an inflammatory response to oral pathogens growing on the implant surface threatens to reduce service life leading to eventual implant failure, and such an outcome will have adverse impact on public health and create significant health care costs. Here we report a predictive approach to peptide design, which enabled us to engineer a bifunctional peptide to combat bacterial colonization and biofilm formation, reducing the adverse host inflammatory immune response that destroys the tissue surrounding implants and shortens their lifespans. This bifunctional peptide contains a titanium-binding domain that recognizes and binds with high affinity to titanium implant surfaces, fused through a rigid spacer domain with an antimicrobial domain. By varying the antimicrobial peptide domain, we were able to predict the properties of the resulting bifunctional peptides in their entirety by analyzing the sequence-structure-function relationship. These bifunctional peptides achieve: 1) nearly 100% surface coverage within minutes, a timeframe suitable for their clinical application to existing implants; 2) nearly 100% binding to a titanium surface even in the presence of contaminating serum protein; 3) durability to brushing with a commercially available electric toothbrush; and 4) retention of antimicrobial activity on the implant surface following bacterial challenge. A bifunctional peptide film can be applied to both new implants and/or repeatedly applied to previously placed implants to control bacterial colonization mitigating peri-implant disease that threatens dental implant longevity.

Repeatedly Applied Peptide Film Kills Bacteria on Dental Implants

The rising use of titanium dental implants has increased the prevalence of peri-implant disease that shortens their useful life. A growing view of peri-implant disease suggests that plaque accumulation and microbiome dysbiogenesis trigger a host immune inflammatory response that destroys soft and hard tissues supporting the implant. The incidence of peri-implant disease is difficult to estimate, but with over 3 million implants placed in the USA alone, and the market growing by 500,000 implants/year, such extensive use demands additional interceptive approaches. We report a water-based, nonsur-gical approach to address peri-implant disease using a bifunctional peptide film, which can be applied during initial implant placement and later reapplied to existing implants to reduce bacterial growth. Bifunctional peptides are based upon a titanium binding peptide (TiBP) optimally linked by a spacer peptide to an antimicrobial peptide (AMP). We show herein that dental implant surfaces covered with a bifunctional peptide film kill bacteria. Further, using a simple protocol for cleaning implant surfaces fouled by bacteria, the surface can be effectively recoated with TiBP-AMP to regain an antimicrobial state. Fouling, cleansing, and rebinding was confirmed for up to four cycles with minimal loss of binding efficacy. After fouling, rebinding with a water-based peptide film extends control over the oral microbiome composition, providing a novel nonsurgical treatment for dental implants.

A critical review of multifunctional titanium surfaces: New frontiers for improving osseointegration and host response, avoiding bacteria contamination

Evolution of metal implants progressively shifted the focus from adequate mechanical strength to improved biocompatibility and absence of toxicity and, finally, to fast osseointegration. Recently, new frontiers and challenges of Ti implants have been addressed to improvement of bioactivity, fighting of bacterial infection and biofilm formation, as well as modulation of inflammation. This is closely related to the clinical demand of multifunctional implants able to simultaneously have a number of specific responses with respect to body fluids, cells (osteoblasts, fibroblasts, macrophages) and pathogenic agents (bacteria, viruses). This complex system of multiple biological stimuli and surface responses is a major arena of the current research on biomaterials and biosurfaces. This review covers the strategies explored to this purpose since 2010 in the case of Ti and Ti alloys, considering that the number of related papers doubled about in the last seven years and no review has comprehensively covered this engaging research area yet. The different approaches followed for producing multifunctional Ti-based surfaces involve the use of thick and thin inorganic coatings, chemical surface treatments, and functionalization strategies coupled with organic coatings.

STATEMENT OF SIGNIFICANCE

According to the clinical demand of multifunctional implants able to simultaneously have a number of specific responses with respect to body fluids, cells and pathogenic agents, new frontiers of Ti implants have been addressed to improvement of bioactivity, fighting of bacterial infection and biofilm formation, as well as modulation of inflammation. Literature since 2010 is here reviewed. Several strategies for getting bioactive and antibacterial actions on Ti surfaces have been suggested, but they still need to be optimized with respect to several concerns. A further step will be to combine on the same surface a proven ability of modulation of inflammatory response. The achievement of multifunctional surfaces able to modulate inflammation and to promote osteogenesis is a grand challenge.

Early intervention of peri-implantitis and periodontitis using a mouse model

BACKGROUND

Peri-implantitis is an inflammatory response to bacterial biofilm resulting in bone loss and can ultimately lead to implant failure. Because of the lack of predictable treatments available, a thorough understanding of peri-implantitis's pathogenesis is essential. The objective of this study is to evaluate and compare the response of acute induced peri-implantitis and periodontitis lesions after insult removal.

METHODS

Implants were placed in one-month-old C57BL/6J male mice eight weeks post extraction of their left maxillary molars. Once osseointegrated, ligatures were placed around the implants and contralateral second molars of the experimental groups. Controls did not receive ligatures. After one week, half of the ligatures were removed, creating the ligature-retained and ligature-removed groups. Mice were sacrificed at two time points, 5 and 14 days, from ligature removal. The specimens were analyzed via micro-computed tomography and histology.

RESULTS

By 5 and 14 days after ligature removal, the periodontitis group experienced significant bone gain, whereas the peri-implantitis group did not. Histologically, all implant groups exhibited higher levels of cellular infiltrate than any of the tooth groups. Osteoclast numbers increased in peri-implantitis and periodontitis ligature-retained groups and decreased following insult removal. Collagen was overall more disorganized in peri-implantitis than periodontitis for all groups. Peri-implantitis experimental groups revealed greater matrix metalloproteinase-8 and NF-kB levels than periodontitis.

CONCLUSIONS

Implants respond slower and less favorably to insult removal than teeth. Future research is needed to characterize detailed peri-implantitis disease pathophysiology.

Combination of ultrasonic decontamination, soft tissue curettage, and submucosal air polishing with povidone-iodine application for non-surgical therapy of peri-implantitis: 12 Month clinical outcomes

BACKGROUND

The aim of this study is to evaluate clinical outcomes of a concept for non-surgical peri-implantitis combining stepwise mechanical debridement measures with adjuvant povidone-iodine application with and without systemic antibiotics.

METHODS

Forty-five patients with chronic periodontitis and a total of 164 screw-typed implants with peri-implantitis were included. Peri-implantitis was defined as radiographic bone loss of > 2 mm, probing depth (PD) ≥5 mm with bleeding on probing (BOP). Stepwise treatment of implants was performed with ultrasonic debridement, soft tissue curettage (STC), glycine powder air polishing (GPAP), and a repeated submucosal application of povidone-iodine. Teeth with PD > 4 mm were treated simultaneously according to the same concept except STC. In cases with severe periodontitis (n = 24), amoxicillin and metronidazole (AM) were prescribed for 7 days.

RESULTS

After 12 months, implants treated without AM showed significant reductions (P < 0.05) of mean PD (1.4 ± 0.7 mm), clinical attachment level (CAL) (1.3 ± 0.8 mm), and BOP (33.4% ± 17.2%). In deep pockets (PD > 6 mm) changes of mean PD (2.3 ± 1.3 mm), CAL (2.0 ± 1.6 mm), and BOP (44.0% ± 41.7%) were more pronounced. Intake of AM did not significantly influence the changes in these parameters. However, the reduction of implant sites with PD > 4 mm and BOP was significantly higher in patients with AM than in those without AM (31.8% ± 12.6% versus 20.8% ± 14.7%; P < 0.05).

CONCLUSIONS

The combination of ultrasonic debridement, STC, and GPAP with adjuvant povidone-iodine led to significant clinical improvements at implants. Systemic antibiotics had limited effects on the reduction of persisting implant sites with treatment need.

LOX-1 is involved in IL-1β production and extracellular matrix breakdown in dental peri-implantitis

PURPOSE

To explore whether lectin-type oxidized LDL receptor 1 (LOX-1), interleukin 1 beta (IL-1β), matrix metalloproteinase 2 (MMP2) and matrix metalloproteinase 9 (MMP9) are involved in the nosogenesis of human dental peri-implantitis and determine the role of LOX-1 in IL-1β, MMP2 and MMP9 production in response to Porphyromonas gingivalis.

METHODS

Peri-implant crevicular fluid (PICF) was collected from ten patients with healthy implants and ten patients with peri-implantitis. The LOX-1 protein in PICF was detected by Western-blot, and the expression of LOX-1 in superficial gingiva of peri-implantitis patients was detected by immunofluorescence staining. The IL-1β, MMP2 and MMP9 proteins in PICF were detected by enzyme-linked immunosorbent assay (ELISA). THP-1 macrophages were pretreated with neutralizing antibody (LOX-1) and inhibitors (LOX-1 and c-Jun N-terminal kinase, JNK) to evaluate the role of LOX-1 and JNK in IL-1β production, as well as the role of LOX-1 in MMP2 and MMP9 production in response to P. gingivalis by quantitative polymerase chain reaction (RT-PCR) and Western-blot.

RESULTS

LOX-1, IL-1β, MMP2 and MMP9 increased in PICF of peri-implantitis patients and in THP-1 macrophages on P. gingivalis stimulation. IL-1β, MMP2 and MMP9 production in response to P. gingivalis in THP-1 macrophages was dependent on LOX-1. JNK was responsible for LOX-1 induced IL-1β production as a result of P. gingivalis infection.

CONCLUSION

LOX-1 is involved in IL-1β production and extracellular matrix breakdown is a novel inflammatory pathway trigger and potential drug target in human dental peri-implantitis.

Oral Health: The Need for Both Conventional Microbial and Molecular Characterization

This study aims to consider the microbial distribution in oral disease, as well as gene analysis and expression, in elucidating: 1, the fundamental underpinnings of oral disease, and 2, the potential relationship between oral diseases and systemic health. A key focus is identifying the microbiota associated with oral disease manifestations characterized by both conventional microbiological and molecular methods. Variations in the observed microbial populations characterized by conventional and molecular approaches have been identified for caries, periodontitis, peri-implantitis, and stomatitis. The discovery of therapeutic approaches for oral disease will require comprehensive microbial and genomic analysis. This study evaluated the current state of the relevant microbial and genomic information for several prevalent oral diseases.

Influence of surface modified dental implant abutments on connective tissue attachment: A systematic review

OBJECTIVE

Determine whether surface modified prosthetic abutments for dental implants influence connective tissue attachment to the implant-abutment system.

DESIGN

A systematic review was conducted using the MEDLINE-PubMed database, with two independent reviewers filtering the titles and abstracts. Two reviewers assessed all potentially relevant articles. An assessment was carried out on the level of evidence of the research according to the guidelines of the Oxford Centre for Evidence-Based Medicine (OCEBM).

RESULTS

After an initial search, 109 potentially relevant articles were found. After reading the titles and abstracts, 99 articles were excluded because the surface treatment was limited to the implant and not to the abutment, or because different materials were analysed instead of surface treatments; 28 were also duplicate articles. An additional 6 research studies were included that were of interest and were found by reading the references of the included articles. The studies included are: 7 in vitro studies, 5 experimental studies in animals, 2 clinical trials in humans and 2 clinical cases.

CONCLUSION

Surface modification for prosthetic abutments on dental implants can achieve connective tissue attachment to the abutment; however, more studies should be conducted in humans to obtain more and better evidence of these results.

Effects of Two Diode Lasers With and Without Photosensitization on Contaminated Implant Surfaces: An Ex Vivo Study

OBJECTIVE

The aim of this ex vivo study is to assess decontamination potential of two different diode laser wavelengths, with or without the aid of photodynamic therapy, on dental implant surfaces and to evaluate the harmful potential of temperature increase during laser irradiation.

MATERIALS AND METHODS

One hundred thirty-two machined sterile implants were placed into sterile porcine bone blocks with standardized coronal angular bony defects and inoculated with Streptococcus sanguinis. Four different treatment protocols were used: 810 or 980 nm laser, with or without photosensitization. Two nontreated control groups were used, one with samples coated with indocyanine green dye. Samples were rinsed and plated on agar plates for subsequent colony count. Irradiation was repeated without contamination at room temperature and in a 37°C water bath monitoring the temperature variation.

RESULTS

There is a statistically significant decontamination effect when the laser is used. Both wavelengths minimize contamination. There was modest improvement given by the photosensitization being more marked in the 810 nm groups, but was not statistically significant compared to laser only. A critical temperature increase was never observed when the sample was in a 37°C water bath.

CONCLUSIONS

The use of both diode laser wavelengths in implant surface decontamination was efficacious regardless of the use of photosensitization and without dangerous increase of temperature.

Thermodynamic Effects of 3 Different Diode Lasers on an Implant-Bone Interface: An Ex-Vivo Study With Review of the Literature

The aim of this study is to assess the increase of temperature following laser irradiation with 810 nm, 980 nm, and 1064 nm diode laser wavelengths, of an implant under conditions that more closely replicate those of the human body. A 4 × 14 mm machined surface implant was placed in a porcine rib to replicate the conductivity of heat given by the bone. A peri-implant vertical defect was made that was 2 mm wide and 2 mm deep to simulate bone resorption. Two thermocouples were positioned crestally and apically on the implant surface. The tip of the laser was kept 3 mm away from the surface and continuously moved in an up-and-down and side-to-side fashion, inside the defect for 60 seconds. Initial temperatures and the time needed to reach an increase of 10°C were recorded. The experiment was repeated at room temperature and in a 37°C water bath with the following settings: 0.6 W, 0.8 W, 1 W continuous and repeated in pulsed. A critical increase of temperature of more than 10°C is reached with all lasers at 0.8 W and 1 W in continuous mode at room temperature. Only the 1064 nm diode laser reached the critical increase at 0.8 W in pulsed mode. No critical increase of temperature was registered with other settings and when the bone block was placed in a 37°C water bath. The results of this study suggest that use of these diode lasers does not cause a harmful increase in temperature when used under conditions similar to those of the human body.