The Current Weight of Evidence of the Microbiologic Profile Associated With Peri-Implantitis: A Systematic Review

Microbiota of Peri-Implant Healthy Tissues, Peri-Implant Mucositis, and Peri-Implantitis: A Comprehensive Review

Understanding the microbiological profiles of peri-implant conditions is crucial for developing effective preventive and therapeutic strategies. This narrative review analyzes the microbial profiles associated with healthy peri-implant sites, peri-implant mucositis, and peri-implantitis, along with related microbiological sampling and analyses. Healthy peri-implant sites are predominantly colonized by Streptococcus, Rothia, Neisseria, and Corynebacterium species, in addition to Gram-positive cocci and facultatively anaerobic rods, forming a stable community that prevents pathogenic colonization and maintains microbial balance. In contrast, peri-implant mucositis shows increased microbial diversity, including both health-associated and pathogenic bacteria such as red and orange complex bacteria, contributing to early tissue inflammation. Peri-implantitis is characterized by even greater microbial diversity and a complex pathogenic biofilm. Predominant pathogens include Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, Fusobacterium nucleatum, and unique species like Filifactor alocis and Fretibacterium fastidiosum. Additionally, less common species such as Staphylococcus and Enterobacteriaceae, contributing to disease progression through biofilm formation and increased inflammatory response, along with EBV and human cytomegalovirus with a still not defined role, and Candida albicans contribute to disease progression through biofilm formation, immune modulation, and synergistic inter-kingdom interactions. Future research should standardize diagnostic criteria, employ advanced molecular techniques, integrate microbial data with clinical factors, and highlight inter-kingdom interactions.

Biomaterials science and surface engineering strategies for dental peri-implantitis management

Peri-implantitis is a bacterial infection that causes soft tissue inflammatory lesions and alveolar bone resorption, ultimately resulting in implant failure. Dental implants for clinical use barely have antibacterial properties, and bacterial colonization and biofilm formation on the dental implants are major causes of peri-implantitis. Treatment strategies such as mechanical debridement and antibiotic therapy have been used to remove dental plaque. However, it is particularly important to prevent the occurrence of peri-implantitis rather than treatment. Therefore, the current research spot has focused on improving the antibacterial properties of dental implants, such as the construction of specific micro-nano surface texture, the introduction of diverse functional coatings, or the application of materials with intrinsic antibacterial properties. The aforementioned antibacterial surfaces can be incorporated with bioactive molecules, metallic nanoparticles, or other functional components to further enhance the osteogenic properties and accelerate the healing process. In this review, we summarize the recent developments in biomaterial science and the modification strategies applied to dental implants to inhibit biofilm formation and facilitate bone-implant integration. Furthermore, we summarized the obstacles existing in the process of laboratory research to reach the clinic products, and propose corresponding directions for future developments and research perspectives, so that to provide insights into the rational design and construction of dental implants with the aim to balance antibacterial efficacy, biological safety, and osteogenic property.

High-Intensity Focused Ultrasound in Dentistry: A Literature Review

Although high-intensity focused ultrasound (HIFU) has been applied widely in medicine, utilising its non-invasive dual ablation and thermal coagulation properties, its application in dentistry has primarily remained in the research phase, predominantly in in vitro studies. Nonetheless, there has been a consistent increase in the number of publications on this subject in recent decades, focusing on areas such as remineralisation of dentine surfaces, removal of smear layers, drug delivery, and microbial elimination. The number of advantages HIFU can offer, such as its non-surgical nature, absence of ionising radiation, lack of residue, and absence of aerosols, is driving this upward trend, indicating the potential for HIFU in clinical dentistry and ongoing efforts towards developing HIFU-based devices for routine dental use. This succinct review aims to outline the historical context, operational mechanisms of HIFU, summarise recent dental research, and provide a forward-looking perspective on the role of HIFU in modern clinical dentistry.

Effect of bioceramic powder abrasion on different implant surfaces

PURPOSE

Bioceramic coatings have been shown to promote bone repair, which aids in the early integration of implants. This study aimed to evaluate the influence of air abrasion with a bioceramic abrasive on the surface characteristics of different implant materials and surfaces. The dissolution of the applied treatment from the surfaces over 3 weeks was also assessed.

MATERIALS AND METHODS

Discs of three alloys used for dental implants were studied and compared: two types of commercially pure titanium (CpTi)/ (CpTi SLActive) and titanium-zirconia (TiZr). The tested surfaces were: CpTi control (CpC), sandblasted (SB), sandblasted and acid-etched (SBE), and CpTi SLActive®, (TiZr) Roxolid®. Three discs from each group underwent air abrasion with apatite bioceramic powders, 95% hydroxyapatite (HA)/5% calcium oxide (CaO), and 90% hydroxyapatite (HA)/10% calcium oxide (CaO). The treated discs were surface characterized by optical profilometry to obtain surface roughness, scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS) to compare element weight percentages of titanium, calcium, and phosphate. Dissolution was assessed using inductively coupled plasma optic emission spectrometry (ICP-OES).

RESULTS

Bioceramic powders were deposited on all tested surfaces leading to changes in surface characteristics. The only statistically significant differences between the material groups for surface roughness were found with 95% HA/5% CaO powder in the Sp and Rp parameters (p = 0.03 and 0.04, respectively). There were no significant differences in the Ca and P wt% between all groups and powders 95% HA/5% CaO and 90% HA/10% CaO (p = 0.14, 0.18, and p = 0.15, 0.12, respectively). A non-uniform dispersion of the treatment on the surface layer was visible on all treated surfaces. The bioceramic powder continued to dissolute from the tested surfaces for 3 weeks.

CONCLUSION

Bioceramic abrasion modifies implant surface characteristics, although the change in surface characteristics resulting from such treatment was not influenced by the implant material or surface treatment. Air abrasion with hydroxyapatite and calcium oxide bioceramics leaves powder deposits on the treated implant surfaces that could potentially influence the healing of implants affected by peri-implantitis.

Graphene oxide/ε-poly-L-lysine self-assembled functionalized coatings improve the biocompatibility and antibacterial properties of titanium implants

The construction of an antibacterial biological coating on titanium surface plays an important role in the long-term stability of oral implant restoration. Graphene oxide (GO) has been widely studied because of its excellent antibacterial properties and osteogenic activity. However, striking a balance between its biological toxicity and antibacterial properties remains a significant challenge with GO. ε-poly-L-lysine (PLL) has broad-spectrum antibacterial activity and ultra-high safety performance. Using Layer-by-layer self-assembly technology (LBL), different layers of PLL/GO coatings and GO self-assembly coatings were assembled on the surface of titanium sheet. The materials were characterized using scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and contact angle test. The antibacterial properties of Porphyromonas gingivalis (P.g.) were analyzed through SEM, coated plate experiment, and inhibition zone experiment. CCK-8 was used to determine the cytotoxicity of the material to MC3T3 cells, and zebrafish larvae and embryos were used to determine the developmental toxicity and inflammatory effects of the material. The results show that the combined assembly of 20 layers of GO and PLL exhibits good antibacterial properties and no biological toxicity, suggesting a potential application for a titanium-based implant modification scheme.

Bacterial Flora in Screw-Fixed Superstructures with Different Sealing Materials: A Comparative Clinical Trial

A screw-fixed superstructure is predominantly selected for implant prostheses because of the concern regarding developing peri-implantitis, although its infection route remains unclear. Focusing on microleakage from access holes, the present study clinically investigated the bacterial flora in access holes with different sealing materials. We examined 38 sites in 19 patients with two adjacent screw-fixed superstructures. Composite resin was used in the control group, and zinc-containing glass ionomer cement was used in the test group. Bacteria were collected from the access holes 28 days after superstructure placement and were subjected to DNA hybridization analysis. The same patient comparisons of the bacterial counts showed a significant decrease in 14 bacterial species for the red, yellow, and purple complexes in the test group (p < 0.05). In addition, the same patient comparisons of the bacterial ratios showed a significant decrease in six bacterial species for the orange, green, yellow, and purple complexes in the test group (p < 0.05). Furthermore, the same patient comparisons of the implant positivity rates showed a significant decrease in the six bacterial species for the orange, yellow, and purple complexes in the test group. The results of this study indicate that zinc-containing glass ionomer cement is effective as a sealing material for access holes.

The Peri-Implant Microbiome-A Possible Factor Determining the Success of Surgical Peri-Implantitis Treatment?

The objective was to assess the effect of peri-implantitis surgery on the peri-implant microbiome with a follow-up of one year. A total of 25 peri-implantitis patients in whom non-surgical treatment has failed to solve peri-implantitis underwent resective surgical treatment. Their peri-implant pockets were sampled prior to surgical treatment (T0) and one year post treatment (T12). The natural dentition was sampled to analyse similarities and differences with the peri-implantitis samples. Treatment success was recorded. The change in microbial relative abundance levels was evaluated. The microbiota was analysed by sequencing the amplified V3-V4 region of the 16S rRNA genes. Sequence data were binned to amplicon sequence variants that were assigned to bacterial genera. Group differences were analysed using principal coordinate analysis, Wilcoxon signed rank tests, and t-tests. Beta diversity analyses reported a significant separation between peri-implantitis and natural dentition samples on T0 and T12, along with significant separations between successfully and non-successfully treated patients. Eubacterium was significantly lower on T12 compared to T0 for the peri-implantitis samples. Treponema and Eubacterium abundance levels were significantly lower in patients with treatment success on T0 and T12 versus no treatment success. Therefore, lower baseline levels of Treponema and Eubacterium seem to be associated with treatment success of peri-implantitis surgery. This study might aid clinicians in determining which peri-implantitis cases might be suitable for treatment and give a prognosis with regard to treatment success.

Peri-implantitis increases the risk of medication-related osteonecrosis of the jaws associated with osseointegrated implants in rats treated with zoledronate

This study evaluated the peri-implant tissues under normal conditions and under the influence of experimental peri-implantitis (EPI) in osseointegrated implants installed in the maxillae of rats treated with oncologic dosage of zoledronate. Twenty-eight senescent female rats underwent the extraction of the upper incisor and placement of a titanium dental implant (DI). After eight weeks was installated a transmucosal healing screw on DI. After nine weeks, the following groups were formed: VEH, ZOL, VEH-EPI and ZOL-EPI. From the 9th until the 19th, VEH and VEH-EPI groups received vehicle and ZOL and ZOL-EPI groups received zoledronate. At the 14th week, a cotton ligature was installed around the DI in VEH-EPI and ZOL-EPI groups to induce the EPI. At the 19th week, euthanasia was performed, and the maxillae were processed so that at the implanted sites were analyzed: histological aspects and the percentage of total bone tissue (PTBT) and non-vital bone tissue (PNVBT), along with TNFα, IL-1β, VEGF, OCN and TRAP immunolabeling. ZOL group presented mild persistent peri-implant inflammation, higher PNVBT and TNFα and IL-1β immunolabeling, but lower for VEGF, OCN and TRAP in comparison with VEH group. ZOL-EPI group exhibited exuberant peri-implant inflammation, higher PNVBT and TNFα and IL-1β immunolabeling when compared with ZOL and VEH-EPI groups. Zoledronate disrupted peri-implant environment, causing mild persistent inflammation and increasing the quantity of non-vital bone tissue. Besides, associated with the EPI there were an exacerbated inflammation and even greater increase in the quantity of non-vital bone around the DI, which makes this condition a risk factor for medication-related osteonecrosis of the jaws.

Indian Society of Periodontology Good Clinical Practice Recommendations for Peri-implant Care

Current implant therapy is a frequently employed treatment for individuals who have lost teeth, as it offers functional and biological advantages over old prostheses. Concurrently, active exploration of intervention strategies aims to prevent the progression of peri-implant diseases and manage the existing peri-implant tissue damage. Indian Society of Periodontology has recognized the need for systematic documents to update the everyday clinical practice of general dental practitioners and has provided evidence-based consensus documents, namely good clinical practice recommendations from time to time to raise the oral health-related awareness and standards of oral health-care delivery across the country. The current clinical practice recommendations focused on peri-implant care to bridge the gap between academic theory and clinical practice by compiling evidence-based suggestions for preventing and treating peri-implant diseases. Twenty-eight subject experts across the country prepared these recommendations after a thorough literature review and group discussions. The document has been prepared in three sections covering peri-implant health and maintenance, peri-implant mucositis, and peri-implantitis. It will be a quick and concise reference for oral implant practitioners in patient management. The guidelines provide distinct definitions, signs, and symptoms, treatment required; recall visit specifications for plausible clinical case situations, and home-care recommendations regarding maintaining peri-implant health. The document advocates combined efforts of oral implant practitioners and the population at large with evidence-based, integrated, and comprehensive peri-implant care. By providing accessible, applicable guidance, these guidelines would empower dental professionals to uphold the well-being of implant patients and ensure the long-term success of implant therapy.

Microbiota associated with peri-implantitis-A systematic review with meta-analyses

AIM

To answer the following PECO question: "In systemically healthy human subjects (P), which are the differences between peri-implantitis (E) and peri-implant health/mucositis (C) in terms of bacterial presence/count (O)?"

MATERIALS AND METHODS

Cross-sectional studies fulfilling specific inclusion criteria established to answer the PECO question were included. Two review authors independently searched for studies, screened the titles and abstracts, did full-text analysis, extracted the data from the included reports, and performed the risk of bias assessment through an adaptation of the Newcastle/Ottawa tool for cross-sectional studies and of the JBI critical appraisal checklist. In case of disagreement, a third reviewer author took the final decision. Study results were summarized using random effects meta-analyses.

RESULTS

A total of 12 studies were included, involving 1233 participants and 1513 implants. Peri-implantitis was associated with the presence of S. epidermidis (Odds ratio, OR = 10.28 [95% Confidence interval, CI: 1.26-83.98]), F. nucleatum (OR = 7.83 [95% CI: 2.24-27.36]), T. denticola (OR = 6.11 [95% CI: 2.72-13.76]), T. forsythia (OR = 4.25 [95% CI: 1.71-10.57]), P. intermedia (OR = 3.79 [95% CI: 1.07-13.35]), and P. gingivalis (OR = 2.46 [95% CI: 1.21-5.00]). Conversely, the presence of A. actinomycetemcomitans (OR = 3.82 [95% CI: 0.59-24.68]), S. aureus (OR = 1.05 [95% CI: 0.06-17.08]), and C. rectus (OR = 1.48 [95% CI: 0.69-3.17]) was not associated with peri-implantitis.

CONCLUSIONS

Peri-implantitis is associated with the presence of S. epidermidis and specific periodontopathogens (P. gingivalis, T. forsythia, T. denticola, F. nucleatum, and P. intermedia). (CRD42021254589).

Lung Abscess Caused by Tannerella forsythia Infection: A Case Report

Background

Tannerella forsythia is a gram-negative anaerobic bacterium commonly found in the oral cavity. It is among the common pathogenic bacteria associated with gingivitis, chronic periodontitis, and aggressive periodontitis. However, there is currently no literature discussing lung abscesses primarily caused by T. forsythia infection.

Presentation

This article presents the case of a 55-year-old male with a massive lung abscess. The patient underwent ultrasound-guided percutaneous drainage, and the sample was sent for pathogen metagenomic next-generation sequencing (mNGS) testing. The test indicated that the lung abscess was primarily caused by T. forsythia infection. A literature review was conducted to understand the characteristics of this pathogen as well as its clinical features and suitable treatment approaches.

Conclusion

Currently, there is no literature specifically mentioning T. forsythia as a primary pathogen causing lung abscesses. This anaerobic bacterium is commonly found in the oral cavity and is difficult to cultivate using routine culture methods. mNGS emerges as a value diagnostic method for identifying this pathogen. Treatment recommendations include drainage and antibiotic selection encompassing common periodontal pathogens such as red complex bacteria and Actinomyces.

Oral microbial colonization on titanium and polyetheretherketone dental implant healing abutments: An in vitro and in vivo study

STATEMENT OF PROBLEM

Although polyetheretherketone (PEEK) implant healing abutments have become popular because of their esthetic, mechanical, and chemical properties, studies analyzing oral polymicrobial adhesion to PEEK abutments are lacking.

PURPOSE

The purpose of this in vitro and in vivo study was to evaluate oral microbial adhesion and colonization on titanium (Ti) and PEEK healing abutments.

MATERIAL AND METHODS

Ti (N=35) and PEEK substrates (N=35) were evaluated in vitro in terms of the initial adhesion (1 hour) or biofilm accumulation (48 hours) of Candida albicans and a polymicrobial inoculum using stimulated human saliva to mimic a diverse oral microbiome. Surface decontamination ability was evaluated after 24 hours of in vitro biofilm formation after exposure to an erbium-doped yttrium aluminum garnet (Er:YAG) laser. Conventional and flowable composite resin veneering on PEEK was also tested for microbial adhesion. In addition, an in vivo model with 3 healthy volunteers was conducted by using a palatal appliance containing the tested materials (3 or 4 specimens of each material per appliance) for 2 days to evaluate the effect of substrate on the microbial profile. Biofilms were evaluated by live cell counts and scanning electron microscopy images, and the microbial profile by Checkerboard deoxyribonucleic acid (DNA)-DNA hybridization. The t test and Mann-Whitney test were used to compare the groups (α=.05).

RESULTS

PEEK and Ti materials showed similar fungal adhesion (P>.05). Although the PEEK surface limited the initial in vitro polymicrobial adhesion (approximately 2 times less) compared with Ti (P=.040), after 48 hours of biofilm accumulation, the microbial load was statistically similar (P=.209). Er:YAG laser decontamination was more effective on PEEK than on Ti surfaces, reducing approximately 11 times more microbial accumulation (P=.019). Both composite resins tested showed similar microbial adhesion (1 hour). In vivo, the PEEK material showed reduced levels of 6 bacterial species (P<.05), including the putative pathogen Treponema denticola.

CONCLUSIONS

Although PEEK and Ti had similar bacterial and fungus biofilm attachment and accumulation, PEEK promoted a host-compatible microbial profile with a significantly reduced T. denticola load.

The Impact of Smoking on Peri-implant Microbiota: A Systematic Review

OBJECTIVES

Peri-implantitis is associated with bacterial plaque biofilms and with patients who have a history of periodontitis. Smoking is a risk factor for periodontitis, but the relationship between smoking and peri-implantitis is unclear. The aim of this systematic review was to assess evidence ascertaining the relationship between smoking and peri-implant microbiota.

DATA SOURCES

An electronic search was conducted in the MEDLINE/PubMed, Embase and Scopus® databases in duplicate up to January 2023 without language restrictions. Studies were considered eligible for inclusion if they involved evaluation of the peri-implant microbiota of smokers and nonsmokers. Methodological quality was assessed with the adapted Newcastle-Ottawa scale.

STUDY SELECTION

Fourteen studies were identified for inclusion in the present study, and 85.7% of the studies were defined as medium to high methodological quality. Overall, the evidence presented in this review was limited to medium to high methodological quality. The data indicates that significantly higher frequencies of anaerobic pathogens are detectable in healthy peri-implant tissues of smokers. A lower diversity of microbiota was observed in healthy peri-implant sites of smokers. In the transition from clinically healthy to a diseased status, smoking shaped a reduced peri-implant microbiota by depleting commensal and enriching pathogenic species.

CONCLUSIONS

The composition of peri-implant microbiota may be influenced by smoking. More studies are needed to determine the impact of smoking on peri-implant microbiota.

CLINICAL SIGNIFICANCE

In the transition from clinically healthy to a diseased status, smoking shaped a reduced peri-implant microbiota by depleting commensal and enriching pathogenic species. The composition of peri-implant microbiota may be influenced by smoking.

Smart stimuli-responsive hydrogels for drug delivery in periodontitis treatment

Periodontitis is a chronic inflammatory disease initiated by pathogenic biofilms and host immunity that damages tooth-supporting tissues, including the gingiva, periodontal ligament and alveolar bone. The physiological functions of the oral cavity, such as saliva secretion and chewing, greatly reduce the residence of therapeutic drugs in the area of a periodontal lesion. In addition, complex and diverse pathogenic mechanisms make effectively treating periodontitis difficult. Therefore, designing advanced local drug delivery systems and rational therapeutic strategies are the basis for successful periodontitis treatment. Hydrogels have attracted considerable interest in the field of periodontitis treatment due to their biocompatibility, biodegradability and convenient administration to the periodontal pocket. In recent years, the focus of hydrogel research has shifted to smart stimuli-responsive hydrogels, which can undergo flexible sol-gel transitions in situ and control drug release in response to stimulation by temperature, light, pH, ROS, glucose, or enzymes. In this review, we systematically introduce the development and rational design of emerging smart stimuli-responsive hydrogels for periodontitis treatment. We also discuss the state-of-the-art therapeutic strategies of smart hydrogels based on the pathogenesis of periodontitis. Additionally, the challenges and future research directions of smart hydrogels for periodontitis treatment are discussed from the perspective of developing efficient hydrogel delivery systems and potential clinical applications.

Current Data on Oral Peri-Implant and Periodontal Microbiota and Its Pathological Changes: A Systematic Review

The 5- and 10-year implant success rates in dentistry are nearly 90%. Prevalence of peri-implant diseases is 10% for peri-implantitis and 50% for peri-implant mucositis. To better understand these inflammatory pathologies of infectious origin, it is important to know if the composition of the peri-implant microbiota is comparable with the periodontal microbiota in healthy and pathological conditions. New generation sequencing (NGS) is a recent metagenomic method that analyzes the overall microorganisms present in an ecological niche by exploiting their genome. These methods are of two types: 16S rRNA sequencing and the shotgun technique. For several years, they have been used to explore the oral, periodontal, and, more specifically, peri-implant microbiota. The aim of this systematic review is to analyze the recent results of these new explorations by comparing the periodontal and peri-implant microbiota in patients with healthy and diseased sites and to explore the microbiological characteristics of peri-implantitis. A better knowledge of the composition of the peri-implant microbiota would enable us to optimize our therapeutic strategies. An electronic systematic search was performed using the medical databases PubMed/Medline, Cochrane Library, and ScienceDirect, and Periodontology 2000. The selected articles were published between January 2015 and March 2021. Inclusion criteria included clinical studies comparing healthy and pathological periodontal and peri-implant microbiota exclusively using 16S rRNA sequencing or shotgun sequencing, with enrolled populations free of systemic pathology, and studies without substantial bias. Eight articles were selected and reviewed. All of them used 16S rRNA sequencing exclusively. The assessment of these articles demonstrates the specific character of the peri-implant microbiota in comparison with the periodontal microbiota in healthy and pathological conditions. Indeed, peri-implant diseases are defined by dysbiotic bacterial communities that vary from one individual to another, including known periodontopathogens such as Porphyromonas gingivalis (P.g.) and genera less mentioned in the periodontal disease pattern such as Filifactor alocis. Examination of peri-implant microbiota with 16S rRNA sequencing reveals differences between the periodontal and peri-implant microbiota under healthy and pathological conditions in terms of diversity and composition. The pattern of dysbiotic drift is preserved in periodontal and peri-implant diseases, but when comparing the different types of pathological sites, the peri-implant microbiota has a specificity in the presence of bacteria proper to peri-implantitis and different relative proportions of the microorganisms present.

Do the progression of experimentally induced gingivitis and peri-implant mucositis present common features? A systematic review of clinical human studies

This systematic review evaluated the features of the progression of experimentally induced gingivitis and peri-implant mucositis in humans. Included were studies that evaluated clinical, immunological, or microbiological responses between experimentally induced gingivitis and peri-implant mucositis in periodontally healthy patients. A total of 887 articles were initially identified, but only 12 were included in the final analysis. Implants accumulate less biofilm and suffer the most heterogeneous alterations in the microbiota, in the abstinence of oral hygiene, compared with the tooth. Interestingly, although dental implants presented less biofilm accumulation, the peri-implant mucosa showed a more exacerbated clinical response than the gingival tissue. The risk of bias of the selected studies was moderate to low, with one study presenting serious risk. The progression events of peri-implant mucositis were similar to those of experimental gingivitis but led to a different host response. This review was registered in the PROSPERO database CRD420201 123360.

In vitro antimicrobial effect of titanium anodization on complex multispecies subgingival biofilm

Anodization is a routine industrial galvanic method that produces a titanium oxide layer on the surface of titanium. Considering the possibility that this technique could influence microbial adsorption and colonization, this in vitro study was conducted to evaluate the impact of a process of anodization applied to a titanium surface on the microbial profile of multispecies subgingival biofilm. Titanium discs produced by using two different processes-conventional and Anodization-were divided into two groups: conventional titanium discs with machined surface (cpTi) Control Group and titanium discs with anodic oxidation treatment (anTi) Test Group. Subgingival biofilm composed of 33 species was formed on the titanium discs that were positioned vertically in 96-well plates, for 7 days. The proportions and the counts of microbial species were determined using a DNA-DNA hybridization technique, and data were evaluated using Mann-Whitney test (p < 0.05). Mean total bacterial counts were lower in Test Group in comparison with Control Group (p < 0.05). Nine bacterial species differed significantly, and were found in higher levels in Control Group in comparison with Test Group, including T. forsythia, E. nodatum, and F. periodonticum. In conclusion, titanium discs with anodization could alter the microbial profile of the biofilm formed around them. Further clinical studies should be conducted to confirm the clinical impact of these findings.

Systematic and scoping reviews to assess biological parameters

INTRODUCTION

The evidence synthesis approach compiling biological/laboratory data is effective in advancing health-related knowledge. However, this approach is still underused in the oral health field.

METHODS

This Commentary discusses the opportunities and challenges of systematic and scoping reviews of laboratory data in dentistry. Special focus is put on the potential of these reviews to elucidate etiological and treatment concepts of oral diseases, such as periodontitis and periimplantitis.

RESULTS

The following difficulties associated with such studies are discussed: (i) selection of ideal study design, (ii) assessment of "risk of bias" and definition of "certainty of evidence", (iii) evidence assembly and summary, and (iv) paper review process.

DISCUSSION

Despite those challenges, high-quality reviews integrating laboratory data may generate relevant scientific information and help identify new avenues for future investigations. Experts in different oral health topics should build a process capable of helping researchers assemble and interpret these types of data.

Polymicrobial biofilms related to dental implant diseases: unravelling the critical role of extracellular biofilm matrix

Biofilms are complex tri-dimensional structures that encase microbial cells in an extracellular matrix comprising self-produced polymeric substances. The matrix rich in extracellular polymeric substance (EPS) contributes to the unique features of biofilm lifestyle and structure, enhancing microbial accretion, biofilm virulence, and antimicrobial resistance. The role of the EPS matrix of biofilms growing on biotic surfaces, especially dental surfaces, is largely unravelled. To date, there is a lack of a broad overview of existing literature concerning the relationship between the EPS matrix and the dental implant environment and its role in implant-related infections. Here, we discuss recent advances in the critical role of the EPS matrix on biofilm growth and virulence on the dental implant surface and its effect on the etiopathogenesis and progression of implant-related infections. Similar to other biofilms associated with human diseases/conditions, EPS-enriched biofilms on implant surfaces promote microbial accumulation, microbiological shift, cross-kingdom interaction, antimicrobial resistance, biofilm virulence, and, consequently, peri-implant tissue damage. But intriguingly, the protagonism of EPS role on implant-related infections and the development of matrix-target therapeutic strategies has been neglected. Finally, we highlight the need for more in-depth analyses of polymicrobial interactions within EPS matrix and EPS-targeting technologies' rationale for disrupting the complex biofilm microenvironment with more outstanding translation to implant applications in the near future.

Effects of titanium dioxide microparticles and nanoparticles on cytoskeletal organization, cell adhesion, migration, and proliferation in human gingival fibroblasts in the presence of lipopolysaccharide

BACKGROUND AND OBJECTIVE

Titanium wear particles may participate in the etiology of peri-implantitis. However, the influence of titanium wear particles on biological behavior of human gingival fibroblasts (HGFs) in the presence of LPS is still not clear. The present study demonstrated the effects of titanium dioxide micro- and nanoparticles (TiO₂  MPs and NPs) on HGF cell viability, cytoskeletal organization, adhesion, migration, and proliferation in vitro, and LPS was used to mimic the in vivo condition.

METHODS

Primary HGFs were treated with TiO₂ MPs (primary particle size <5 μm, 0.1 mg/ml) and NPs (primary particle size <100 nm, 0.1 mg/ml) with or without 1 μg/ml LPS. The effects of TiO₂ MPs and NPs on HGFs cell viability was measured by CCK-8 assay. The proliferation of HGF was detected by Ki67 nuclear staining. The confocal laser scanning microscope (CLSM) was used to detect the internalization of TiO₂ MPs and NPs in HGFs as well as the arrangement of F-actin, vinculin, and vimentin organization. Wound healing assay and transwell assay were performed to measure the migration of HGFs induced by TiO₂ MPs and NPs. Cell adhesion was measured using fibronectin-coated plates. The relative mRNA and protein expression of adhesion relative protein such as focal adhesion kinase (FAK), fibronectin (FN), and type I collagen (COL1) were measured using quantitative RT-PCR and western blot analysis. One-way analysis of variance (ANOVA) and Student's t-test were used to analyze the statistical significance, and p < .05 was considered statistically significant.

RESULTS

TiO₂ NPs significantly inhibited HGF cell viability, proliferation, and migration compared with TiO₂ MPs group and control group. Compared with control group (2.64 ± 0.09), the mean absorbance of the cells in 1 mg/ml TiO₂ MPs group and 0.25 mg/ml TiO₂ NPs group were significantly decreased to 1.93 ± 0.33 (p < .05) and 2.22 ± 0.18 (p < .01), respectively. The cytoskeleton disruption was found in TiO₂ NPs group. The mRNA and protein expression were significantly downregulated by TiO₂ NPs. Furthermore, both TiO₂ NPs and MPs induced more adverse effects on HGFs in the presence of LPS.

CONCLUSION

Our results indicate that TiO₂ NPs but not TiO₂ MPs significantly disrupt the cytoskeletal organization and inhibited cell adhesion, migration, and proliferation of HGFs. However, in the presence of LPS, TiO₂ MPs, and TiO₂ NPs enhance these negative effects in HGFs. Titanium wear particles are probably involved in the initiation and progression of peri-implant diseases.

Tannerella forsythia strains differentially induce interferon gamma-induced protein 10 (IP-10) expression in macrophages due to lipopolysaccharide heterogeneity

Tannerella forsythia is strongly implicated in the development of periodontitis, an inflammatory disease that destroys the bone and soft tissues supporting the tooth.  To date, the knowledge of the virulence attributes of T. forsythia species has mainly come from studies with a laboratory adapted strain (ATCC 43 037). In this study, we focused on two T. forsythia clinical isolates, UB4 and UB20, in relation to their ability to activate macrophages. We found that these clinical isolates differentially induced proinflammatory cytokine expression in macrophages. Prominently, the expression of the chemokine protein IP-10 (CXCL10) was highly induced by UB20 as compared to UB4 and the laboratory strain ATCC 43 037. Our study focused on the lipopolysaccharide component (LPS) of these strains and found that UB20 expressed a smooth-type LPS, unlike UB4 and ATCC 43 037 each of which expressed a rough-type LPS. The LPS from UB20, via activation of TLR4, was found to be a highly potent inducer of IP-10 expression via signaling through STAT1 (signal transducer and activator of transcription-1). These data suggest that pathogenicity of T. forsythia species could be strain dependent and the LPS heterogeneity associated with the clinical strains might be responsible for their pathogenic potential and severity of periodontitis.

Human Umbilical Cord Mesenchymal Stem Cells: Current Literature and Role in Periodontal Regeneration

Periodontal disease can cause irreversible damage to tooth-supporting tissues such as the root cementum, periodontal ligament, and alveolar bone, eventually leading to tooth loss. While standard periodontal treatments are usually helpful in reducing disease progression, they cannot repair or replace lost periodontal tissue. Periodontal regeneration has been demonstrated to be beneficial in treating intraosseous and furcation defects to varied degrees. Cell-based treatment for periodontal regeneration will become more efficient and predictable as tissue engineering and progenitor cell biology advance, surpassing the limitations of present therapeutic techniques. Stem cells are undifferentiated cells with the ability to self-renew and differentiate into several cell types when stimulated. Mesenchymal stem cells (MSCs) have been tested for periodontal regeneration in vitro and in humans, with promising results. Human umbilical cord mesenchymal stem cells (UC-MSCs) possess a great regenerative and therapeutic potential. Their added benefits comprise ease of collection, endless source of stem cells, less immunorejection, and affordability. Further, their collection does not include the concerns associated with human embryonic stem cells. The purpose of this review is to address the most recent findings about periodontal regenerative mechanisms, different stem cells accessible for periodontal regeneration, and UC-MSCs and their involvement in periodontal regeneration.

Oral Microbiota in Patients with Peri-Implant Disease: A Narrative Review

Peri-implant infections are the most common complications related to the placement of dental implants. There are many microbial similarities between peri-implantitis and periodontitis but due to current laboratory techniques there are just as many differences. This review was performed to assess changes in the oral microbiota at sites with peri-implant disease, according to the state of the art. The peri-implant microbiota presents a lower microbial quality than the periodontal microbiota, becoming increasingly complex as it progresses from peri-implant mucositis to peri-implantitis. The microbial difference detected between the peri-implant and periodontal microbiota is primarily related to whole bacterial populations, rather than specific bacterial taxa. The use of probiotics could support the reduction of peri-implant pockets, in association with mechanical debridement, due to their mechanism of action of competitive inhibition for adhesion sites. The peri-implant microbiota represents a qualitatively inferior but quantitatively superior bacterial ecosystem for some bacterial genera compared to the periodontal microbiota, showing that a progression from healthy state to peri-implantitis causes changes in microbiota composition in the absence of specific disease-causing bacteria. Transcriptomics could provide useful information for the prevention, diagnosis, and therapy of peri-implant pathology through knowledge of bacterial virulence factors.

Salivary Microbial Dysbiosis Is Associated With Peri-Implantitis: A Case-Control Study in a Brazilian Population

Background and Objectives

The aim of this study was to examine the salivary microbiome in healthy peri-implant sites and those with peri-implantitis.

Methods

Saliva samples were collected from 21 participants with healthy peri-implant sites and 21 participants with peri-implantitis. The V4 hypervariable region of the 16S rRNA gene was sequenced using the Ion Torrent PGM System (Ion 318™ Chip v2 400). The NGS analysis and composition of the salivary microbiome were determined by taxonomy assignment. Downstream bioinformatic analyses were performed in QIIME (v 1.9.1).

Results

Clinical differences according to peri-implant condition status were found. Alpha diversity metrics revealed that the bacterial communities of participants with healthy peri-implant sites tended to have a richer microbial composition than individuals with peri-implantitis. In terms of beta diversity, bleeding on probing (BoP) may influence the microbial diversity. However, no clear partitioning was noted between the salivary microbiome of volunteers with healthy peri-implant sites or volunteers with peri-implantitis. The highest relative abundance of Stenotrophomonas, Enterococcus and Leuconostoc genus, and Faecalibacterium prausnitzii, Haemophilus parainfluenzae, Prevotella copri, Bacteroides vulgatus, and Bacteroides stercoris bacterial species was found in participants with peri-implantitis when compared with those with healthy peri-implant sites.

Conclusion

Differences in salivary microbiome composition were observed between patients with healthy peri-implant sites and those with peri-implantitis. BoP could affect the diversity (beta diversity) of the salivary microbiome.

Bone marrow mesenchymal stem cell sheets with high expression of hBD3 and CTGF promote periodontal regeneration

The multi-bacterial environment of the oral cavity makes it hard for periodontal regeneration. As a class of antimicrobial peptide, beta defensin has been found to show broad-spectrum antibacterial ability. In addition, connective tissue growth factor (CTGF) is demonstrated to play a great role in multi-physiological events such as angiogenesis, wound healing and, more importantly, fibrogenesis. In this study, human β defensin 3 (hBD3) and CTGF were co-transfected into bone marrow derived mesenchymal stem cells (BMSCs) for preparing cell sheets. The transfection efficiency was detected through fluorescence of eGFP and western blot assay. Our results showed that the hBD3 and CTGF proteins were highly and stably expressed in the BMSCs after transfection. The results of RT-PCR and induced differentiation indicated that hBD3 promoted osteogenic differentiation of BMSCs, while CTGF significantly increased fibrogenic differentiation even in the presence of hBD3. The BMSCs acquired stronger capacity in terms of promoting M2 polarization of RAW 264.7 macrophages fulfilled by the transfection and secretion of hBD3 and CTGF. To further evaluate the periodontal remodeling performance of cell sheets, a coralline hydroxyapatite (CHA)-chitosan based hydrogel-human tooth system was designed to simulate the natural periodontal environment. The results showed that dense extracellular matrix, oriented fiber arrangement, and abundant collagen deposition appeared in the area of BMSCs sheets after subcutaneous transplantation. Altogether, our data showed that the lentivirus transfected BMSCs sheets had a promising application prospect for periodontal repair.

Microbial profiles of peri-implant mucositis and peri-implantitis: Submucosal microbial dysbiosis correlates with disease severity

OBJECTIVE

To investigate the microbiome characteristics of peri-implant mucositis (PM) and peri-implantitis (PI), and to analyse the correlation between disease severity and submucosal microbial dysbiosis.

MATERIALS AND METHODS

A cross-sectional study design was conducted. Submucosal biofilm samples from 27 PM sites and 37 PI sites from 64 patients were collected and analysed using 16S rRNA gene sequencing (Illumina). Differences in microbiological profiles between PM and PI were evaluated using the α-diversity, β-diversity and linear discriminant analysis effect size (LEfSe) analysis. The relative abundances of the taxa at the phylum and genus levels were compared using the Wilcoxon rank test and logistic regression. The microbial dysbiosis index (MDI) was calculated, and its relationship with clinical measurements (probing depth, bleeding on probing and marginal bone loss, among others) was analysed using Pearson's correlation coefficient.

RESULTS

The overall microbiome distribution in the PM and PI sites was similar according to α- and β-diversity. Twenty-three taxa at the genus level and two taxa at the phylum level showed significant differences in relative abundance between the two clinical classifications. Five taxa at the genus level were screened out for the MDI calculation after logistic regression. No clinical measurements but marginal bone loss showed a significant positive correlation with microbial dysbiosis.

CONCLUSION

The microbiome richness, diversity and distribution were similar in PM and PI sites, including both common periodontal bacteria and novel species. In addition, an increase in marginal bone loss was significantly associated with submucosal microbial dysbiosis.

Low-Level Laser and Antimicrobial Photodynamic Therapy Reduce Peri-implantitis-related Microorganisms Grown In Vitro

OBJECTIVE

Currently, dental implants are a predictable treatment option for oral rehabilitation; however, complications such as peri-implant diseases are increasing every day. Thus, the aim of this study was to verify the efficacy, in vitro, of two protocols against cultures of periodontal biofilm and Staphylococcus aureus.

MATERIAL AND METHODS

Petri dishes for each of the following groups were used: control groups (C)-plates inoculated with periodontal biofilm (C.B; n = 4) or S. aureus (C.SA; n = 4) without any treatment; laser groups-plates inoculated with periodontal biofilm (low-level laser therapy [LLLT].B; n = 4) or S. aureus (LLLT.SA; n = 4) and treated with LLLT (660 nm, 30 mW, 50 J/cm², and 47 seconds); antimicrobial photodynamic therapy groups (aPDT)-plates inoculated with periodontal biofilm (aPDT.B; n = 4) or S. aureus (aPDT.SA; n = 4) and treated with aPDT (red laser 660 nm, 30 mW, 50 J/cm², 47 seconds + toluidine blue O (TBO) 100 µg/mL, and 1 minute). After treatments were performed, the contents of all plates were diluted and seeded for counting colony-forming units (CFUs).

STATISTICAL ANALYSIS

Results were analyzed with one-way analysis of variance (ANOVA), Tukey's test, comparison of percentages, and independent t-tests with a 5% significance level.

RESULTS

Both treatments, LLLT and aPDT, significantly reduced the number of CFUs for the two types of culture, LLLT.B (3.69 × 10⁶ ± 0.20), aPDT.B (2.79 × 10⁶ ± 0.13), LLLT.SA (4.10 × 10⁶ ± 0.12), and aPDT.SA (3.23 × 10⁶ ± 0.10) when compared with control groups C.B (5.18 × 10⁶ ± 0.43) and C.SA (5.81 × 10⁶ ± 0.16; p = 0.000). When treatment groups were compared separately, there was also a statistically significant difference (p = 0.000). None of the protocols were able to eliminate cultured microorganisms.

CONCLUSION

The LLLT and aPDT protocols effectively reduced cultures of periodontal biofilm and S. aureus in vitro, with the superiority of aPDT.

Consequences of Peri-Implant Bone Loss in the Occlusal Load Transfer to the Supporting Bone in terms of Magnitude of Stress, Strain, and Stress Distribution: A Finite Element Analysis

Methods

Three models of a single internal connection bone level-type implant inserted into a posterior mandible bone section were constructed using a 3D finite element software: one control model without marginal bone loss and two test models, both with a circumferential peri-implant bone defect, one with a 3 mm high defect and the other one 6 mm high. A 150 N static load was tested on the central fossa at 6° relative to the axial axis of the implant.

Results

The results showed differences in the magnitude of strain and stress transferred to the bone between models, being the higher strain found in the trabecular bone around the implant with greater marginal bone loss. Stress distribution differed between models, being concentrated at the cortical bone in the control model and at the trabecular bone in the test models.

Conclusion

Marginal bone loss around dental implants under occlusal loading influences the magnitude and distribution of the stress transferred and the deformation of peri-implant bone, being higher as the bone loss increases.

Bacterial reduction effect of four different dental lasers on titanium surfaces in vitro

Compare the effectiveness of selected dental lasers for decontamination of machined titanium surfaces in vitro. Seventy-two sterile machined surface titanium discs were individually inoculated with strains of Streptococcus mutans (Sm), Streptococcus oralis (So), Aggregatibacter actinomycetemcomitans (Aa), or all three bacteria together (MIX) at 34.0^° C, 20.8% O₂ and 5% CO₂ for 12 h. After incubation, the discs were divided into six groups: 1) no treatment, 2) 0.12% chlorhexidine gluconate (CHX), and 3) 10,600 CO₂, 4) 810 nm diode, 5) 2780 nm Er,Cr:YSGG, 6) 1064 nm Nd:YAG laser groups. After treatment, any remaining viable bacteria were liberated from the discs via sonication, transferred onto brain heart infusion (BHI) agar plates for culturing, and colony-forming units (CFUs) were recorded. Statistical analysis was performed. There were statistically significantly differences (SSD) (p < 0.01) in bacterial reduction of discs individually inoculated with Aa between the Er,Cr:YSGG and Nd:YAG lasers. There was also a SSD (p < 0.01) lower effect with the MIX with the Er,Cr:YSGG compared with all other modalities. Bacterial reduction with the CO₂ was better (p < 0.001) than treatment with CHX or the Er,Cr:YSGG laser on killing of So. Although all modalities of treatment showed a mean of 98% or greater viable bacterial reduction, the most consistent bacterial reduction of all titanium discs was with the Nd:YAG laser (100%).

Zinc- and strontium- co-incorporated nanorods on titanium surfaces with favorable material property, osteogenesis, and enhanced antibacterial activity

Early infection and peri-implantitis after implant restoration are major reasons for dental implant failure. Implant-associated infections are majorly attributed to biofilm formation. In this study, co-incorporated zinc- (Zn-) and strontium- (Sr-) nanorod coating on sandblasted and acid-etched (SLA) titanium (SLA-Zn/Sr) was fabricated by hydrothermal synthesis. It was aimed at promoting osteogenesis while inhibiting biofilm formation. The nanorod-like particles (φ 30-50 nm) were found to be evenly formed on SLA-Zn/Sr (Zn: 1.49 ± 0.16 wt%; Sr: 21.69 ± 2.74 wt%) that was composed of well-crystallized ZnTiO₃ and SrTiO₃ phases. With a sufficient interface bonding strength (42.00 ± 3.00 MPa), SLA-Zn/Sr enhanced the corrosion resistance property of titanium. Besides, SLA-Zn/Sr promoted the cellular initial adhesion, proliferation and osteogenic differentiation of rBMSCs in vitro while inhibiting the adhesion of Staphylococcus aureus and Porphyromonas gingivalis . In addition, through down-regulating icaA gene expression, this novel surface reduced the secretion of polysaccharide intercellular adhesion (reduced by 87.9% compared to SLActive) to suppress the S. aureus biofilm formation. We, therefore, propose a new chemical modification on titanium for multifunctional implant material development. Due to the Zn/Sr co-doping in coating, material properties, early osteogenic effect and antibacterial ability of titanium can be simultaneously enhanced, which has the potential to be applied in dental implantation in the future.

Galectin-3, Possible Role in Pathogenesis of Periodontal Diseases and Potential Therapeutic Target

Periodontal diseases are chronic inflammatory diseases that occur due to the imbalance between microbial communities in the oral cavity and the immune response of the host that lead to destruction of tooth supporting structures and finally to alveolar bone loss. Galectin-3 is a β-galactoside-binding lectin with important roles in numerous biological processes. By direct binding to microbes and modulation of their clearence, Galectin-3 can affect the composition of microbial community in the oral cavity. Galectin-3 also modulates the function of many immune cells in the gingiva and gingival sulcus and thus can affect immune homeostasis. Few clinical studies demonstrated increased expression of Galectin-3 in different forms of periodontal diseases. Therefore, the objective of this mini review is to discuss the possible effects of Galectin-3 on the process of immune homeostasis and the balance between oral microbial community and host response and to provide insights into the potential therapeutic targeting of Gal-3 in periodontal disease.

Current Concepts on the Pathogenesis of Peri-implantitis: A Narrative Review

As implant treatment has been integrated in contemporary dental practice, complications with the forms of peri-implant mucositis and peri-implantitis have also increased in prevalence. Peri-implantitis is the more severe biological complication and is defined as an inflammatory disease affecting peri-implant tissues resulting in bone and eventually implant loss. In addition, the treatment of peri-implantitis has currently become a substantial global economic burden. In the current study, a search was conducted in several electronic databases using specific keywords relevant to the article's main topic. An increasing number of scientific reports have investigated the etiopathology of peri-implant diseases, focusing mainly on peri-implantitis. Microbial biofilm consists an important etiological factor of peri-implant pathology analogous to periodontal diseases. Although several data confirm that peri-implant infections are dominated by gram-negative bacteria, similar to periodontal infections, there is evidence that some cases may harbor a distinct microbiota, including opportunistic microorganisms and/or uncultivable species. Additionally, data support that several parameters, such as genetic predisposition of individual patients, occlusal overload, and local factors such as titanium particles and excess cement, may be implicated in peri-implantitis pathogenesis. Simultaneously, the release of titanium metal particles and their biological consequences or the presence of excess cement in the adjacent peri-implant tissues have also been suggested as factors that contribute to peri-implant pathology. A specific line of research also indicates the role of foreign body response to implant installation. This narrative review aims to discuss the current concepts of etiopathogenetic factors implicated in peri-implantitis.

Microbiological findings in early and late implant loss: an observational clinical case-controlled study

Background

Implants are a predictable and well-established treatment method in dentistry. Nevertheless, looking at possible failures of dental implants, early and late loss have to be distinguished. The intent of the study was to report microbiological findings on the surface of implants with severe peri-implantitis, which had to be explanted.

Methods

53 specimens of implants from 48 patients without severe general illnesses have been examined. The groups investigated were implants that had to be removed in the period of osseointegration (early loss, 13 patients with 14 implants) or after the healing period (late loss, 14 patients with 17 implants). The implant losses were compared with two control groups (implants with no bone loss directly after completed osseointegration, two to four months after implant placement (17 patients with 17 implants) and implants with no bone loss and prosthetic restoration for more than three years (5 patients with 5 implants)). Data about the bacteria located in the peri-implant sulcus was collected using amplification and high throughput sequencing of the 16S rRNA gene.

Results

The biofilm composition differed substantially between individuals. Both in early and late implant loss, Fusobacterium nucleatum and Porphyromonas gingivalis were found to be abundant. Late lost implants showed higher bacterial diversity and in addition higher abundances of Treponema, Fretibacterium, Pseudoramibacter and Desulfobulbus, while microbial communities of early loss implants were very heterogeneous and showed no significantly more abundant bacterial taxa.

Conclusions

Specific peri-implant pathogens were found around implants that were lost after a primarily uneventful osseointegration. P. gingivalis and F. nucleatum frequently colonized the implant in early and late losses and could therefore be characteristic for implant loss in general. In general, early lost implants showed also lower microbial diversity than late losses. However, the microbial results were not indicative of the causes of early and late losses.

Influence of preformed bone defects on key pathogens and bone loss during experimental peri-implantitis formation in a canine model

PURPOSE

To determine the impact of experimentally preformed peri-implant crater-shaped bone defects on the evolution of in situ microbiota and development of bone defects compared to those induced over time by ligature placement only.

METHODS

Implants were installed in the mandibles of eight dogs. Standardized bone defects were preformed in four test animals but not in the other four control animals, prior to implant (3.3 mm × 8 mm) installation. After 2 months of healing, peri-implantitis was induced with silk ligatures in both groups for 2 months. Microbial samples were obtained from implants and teeth for analysis at three time points (qPCR), and the average depths of the bone defects were measured.

RESULTS

At the baseline, the total marker load of periodontal-pathogenic bacteria (TML) for teeth accounted for 5.2% (0-17.4%). After implant healing, TMLs for implants and teeth were comparable (7.1% [0.3-17.4%]). The TML of both groups was 3.5%, 2 months after ligature placement. Bone defects had a mean depth of 1.84 mm at preformed defects and 1.64 mm at control sites (P > 0.05).

CONCLUSION

Preformed defects in the test group showed comparable results to the control group in terms of TML, the incidence of periodontal-pathogenic bacteria, and bone defect depth.

There is still room for improvement in the completeness of abstract reporting according to the PRISMA-A checklist: a cross-sectional study on systematic reviews in periodontology

BACKGROUND

To evaluate the completeness of reporting abstracts of systematic reviews (SRs) before and after the publication of the PRISMA-A checklist in 2013 and to assess if an association exists between abstract characteristics and the completeness of reporting.

METHODS

A systematic search of the literature was conducted in the PubMed and Scopus databases in March 2020. The search focused on the SRs of evaluations of interventions published since 2002 in the field of periodontology. The abstracts of the selected SRs were divided into two groups before and after publication of the PRISMA-A checklist in 2013, and compliance with the 12 items reported in the checklist was evaluated by three calibrated evaluators.

RESULTS

A set of 265 abstracts was included in the study. The total score before (mean score, 53.78%; 95% CI, 51.56-55.90%) and after (mean score, 56.88%; 95% CI, 55.39-58.44%) the publication of the PRISMA-A statement exhibited a statistically significant improvement (P = 0.012*). Nevertheless, only the checklist items included studies and synthesis of the results displayed a statistically significant change after guideline publication. The total PRISMA-A score was higher in the meta-analysis group and in articles authored by more than four authors.

CONCLUSIONS

The impact of the PRISMA-A was statistically significant, but the majority of the items did not improve after its introduction. The editors and referees of periodontal journals should promote adherence to the checklist to improve the quality of the reports and provide readers with better insight into the characteristics of published studies.

Assessment of implant surface and instrument insert changes due to instrumentation with different tips for ultrasonic-driven debridement

Background

To assess the changes of implant surfaces of different roughness after instrumentation with ultrasonic-driven scaler tips of different materials.

Methods

Experiments were performed on two moderately rough surfaces (I—Inicell® and II—SLA®), one surface without pre-treatment (III) and one smooth machined surface (IV). Scaler tips made of steel (A), PEEK (B), titanium (C), carbon (D) and resin (E) were used for instrumentation with a standardized pressure of 100 g for ten seconds and under continuous automatic motion. Each combination of scaler tip and implant surface was performed three times on 8 titanium discs. After instrumentation roughness was assessed by profilometry, morphological changes were assessed by scanning electron microscopy, and element distribution on the utmost surface by energy dispersive X-ray spectroscopy.

Results

The surface roughness of discs I and II were significantly reduced by instrumentation with all tips except E. For disc III and IV roughness was enhanced by tip A and C and, only for IV, by tip D. Instrumentation with tips B, D and E left extensive residuals on surface I, II and III. The element analysis of these deposits proved consistent with the elemental composition of the respective tip materials.

Conclusion

All ultrasonic instruments led to microscopic alterations of all types of implants surfaces assessed in the present study. The least change of implant surfaces might result from resin or carbon tips on machined surfaces.

Dental Implants Surface in vitro Decontamination Protocols

Objective  The number of patients rehabilitated with dental implants has contributed to increased incidence of peri-implant diseases. Due to complex and difficult treatment, peri-implantitis is a challenge and an efficient clinical protocol is not yet established. Aim of this study was to evaluate the efficacy of two protocols for in vitro decontamination of dental implants surface.

Materials and Methods  Twenty titanium implants (BioHE-Bioconect) were used. Implants were divided into five groups ( n = 4). NC group (negative control): sterile implants; PC group (positive control): biofilm contaminated implants; S group: biofilm contaminated implants, brushed with sterile saline; SB group: biofilm contaminated implants, brushed with sterile saline and treated with air-powder abrasive system with sodium bicarbonate (1 minute); and antimicrobial photodynamic therapy (aPDT) group: biofilm contaminated implants, brushed with sterile saline and treated with antimicrobial photodynamic therapy (red laser + toluidine blue O). The implants were contaminated in vitro with subgingival biofilm and distributed in groups PC, S, SB, and aPDT. Each group received the respective decontamination treatment, except groups NC and PC. Then, all implants were placed in tubes containing culture medium for later sowing and counting of colony-forming units (CFUs).

Statistical Analysis  One-way analysis of variance and Tukey tests were performed, at 5% significance level.

Results  Significantly fewer CFUs were observed in the aPDT group (19.38 × 10 ⁵ ) when compared with groups SB (26.88 × 10 ⁵ ), S (47.75 × 10 ⁵ ), and PC (59.88 × 10 ⁵ ) ( p < 0.01). Both the aPDT and SB groups were statistically different from the NC group ( p < 0.01).

Conclusion  Proposed protocols, using air-powder abrasive system with sodium bicarbonate and aPDT, showed to be efficacious in the decontamination of dental implants surface in vitro .

Surface functionalization of titanium substrates with Deoxyribonuclease I inhibit peri-implant bacterial infection

This study aimed to investigate the effect of Deoxyribonuclease I (DNase I) coating on initial adhesion and biofilm formation of peri-implant bacteria. Titanium (Ti), Ti-polydopamine (Ti-PDOP), Ti-PDOP-DNase I and Ti-PDOP-inactivated DNase I samples were studied. The FE-SEM, EDS and XPS were used to confirm that DNase I was coated onto Ti. The initial adhesion and biofilm formation of Aggregatibacter actinomycetemcomitans (A.a) and Fusobacterium nucleatum (F.n) were observed by CLSM. The osteogenic induction of Ti-PDOP-DNase I on MC3T3-E1 cells was investigated by ALP activity and RT-PCR. The adhesion clearance rate of viable bacteria on the surfaces of Ti-PDOP-DNase I was 91.95% for A.a, and 96.37% for F.n, and the 24 h biofilm formation of the bacteria was significantly inhibited. In addition, on DNase I coating, the mRNA level of osteogenic marker genes (alp, opn, bsp, sp7) and the activity of ALP were both up-regulated. Therefore, DNase I coating could be an alternative approach for preventing implant-related infection.

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.

Extracellular biofilm matrix leads to microbial dysbiosis and reduces biofilm susceptibility to antimicrobials on titanium biomaterial: An in vitro and in situ study

OBJECTIVES

To test the role of exopolysaccharide (EPS) polymers matrix to modulate the composition/virulence of biofilms growing on titanium (Ti) surfaces, the effect on antibiotic susceptibility, and whether a dual-targeting therapy approach for disrupted EPS matrix could improve the antimicrobial effect.

MATERIALS AND METHODS

A microcosm biofilm model using human saliva as inoculum was used, and the microbial composition was assessed by checkerboard DNA-DNA hybridization. EPS-enriched biofilms virulence was tested using fibroblast monolayer. Povidone-iodine (PI) was used as EPS-targeting agent followed by amoxicillin + metronidazole antibiotic to reduce bacterial biomass using an in situ model.

RESULTS

An EPS-enriched environment, obtained by sucrose exposure, promoted bacterial accumulation and led to a dysbiosis on biofilms, favoring the growth of Streptococcus, Fusobacterium, and Campylobacter species and even strict anaerobic species related to peri-implant infections, such as Porphyromonas gingivalis and Tannerella forsythia (~3-fold increase). EPS-enriched biofilm transitioned from a commensal aerobic to a pathogenic anaerobic profile. EPS increased biofilm virulence promoting higher host cell damage and reduced antimicrobial susceptibility, but the use of a dual-targeting approach with PI pre-treatment disrupted EPS matrix scaffold, increasing antibiotic effect on in situ biofilms.

CONCLUSION

Altogether, our data provide new insights of how EPS matrix creates an environment that favors putative pathogens growth and shed light to a promising approach that uses matrix disruption as initial step to potentially improve implant-related infections treatment.

A systematic review of the microbiota composition in various peri-implant conditions: data from 16S rRNA gene sequencing

OBJECTIVE

To systematically review the literature regarding the microbiota composition in various peri-implant conditions as analyzed by 16S rRNA gene sequencing methods.

METHODS

Electronic searches were conducted at MEDLINE/PubMed, Scopus, Embase, ScienceDirect and Web of Science databases looking for articles published up to April 2020. Observational prospective investigations were considered with systemically healthy patients and that had presented the description of the microbiota composition of peri-implantitis (PI), peri-implant mucositis (PM) and/or health implants (HI) by using 16S rRNA gene sequencing analysis were considered eligible.

RESULTS

From 1,380 titles found, 8 studies were considered for qualitative analysis. One article was excluded due to high risk of bias, remaining 7 studies for descriptive analysis. In 6 out of 7 studies the PI microbiota was reported as being in relative abundance and variety though with a different composition from those with HI. There was no consensus regarding which condition had more diversity. The main observed phyla among PI were Firmicutes, Bacteroidetes, Actinobacteria, Fusobacteria and Spirochaetes, while the genera were mainly Actinomyces, Eubacterium, Fusobacterium, Mogibacterium, Moraxella, Treponema and Porphyromonas. Comparisons between PI and PM microbiota showed conflicting results: one study suggested that PI has greater bacterial diversity; another study reported the opposite result, while another investigation found similar variety for both conditions.

CONCLUSIONS

The microbiota of peri-implant conditions have been reported as distinct, although the available literature presents discrepancies. Nonetheless, considering the findings in most studies, it can be suggested that the relative abundance of microbiota and bacterial diversity increased with the progress of peri-implant disease.

"Inhibitory effect of Brazilian red propolis on Candida biofilms developed on titanium surfaces"

BACKGROUND

Peri-implant inflammation resulting from the presence of Candida biofilms may compromise the longevity of implant-supported dentures. This study evaluated the inhibitory effect of Brazilian red propolis on mono-species biofilms of C. albicans (ATCC 90028) and co-culture biofilms of C. albicans (ATCC 90028) and C. glabrata (ATCC 2001), developed on titanium surfaces.

METHODS

Titanium specimens were pre-conditioned with artificial saliva and submitted to biofilm formation (1 × 106 CFU/mL). After 24 h (under microaerophilic conditions at 37 °C) biofilms were submitted to treatment for 10 min, according to the groups: sterile saline solution (growth control), 0.12% chlorhexidine and 3% red propolis extract. Treatments were performed every 24 h for 3 days and analyses were conducted 96 h after initial adhesion. After that, the metabolic activity (MTT assay) (n = 12/group), cell viability (CFU counts) (n = 12/group) and surface roughness (optical profilometry) (n = 6/group) were evaluated. Data from viability and metabolic activity assays were evaluated by ANOVA and Tukey tests. Surface roughness analysis was determined by Kruskal Wallis e Mann Whitney tests.

RESULTS

Regarding the mono-species biofilm, the cell viability and the metabolic activity showed that both chlorhexidine and red propolis had inhibitory effects and reduced the metabolism of biofilms, differing statistically from the growth control (p < 0.05). With regards the co-culture biofilms, chlorhexidine had the highest inhibitory effect (p < 0.05). The metabolic activity was reduced by the exposure to chlorhexidine and to red propolis, different from the growth control group (p < 0.05). The surface roughness (Sa parameter) within the mono-species and the co-culture biofilms statistically differed among groups (p < 0.05).

CONCLUSIONS

Brazilian red propolis demonstrated potential antifungal activity against Candida biofilms, suggesting it is a feasible alternative for the treatment of peri-implantitis.

Evaluation of efficacy of non-thermal atmospheric pressure plasma in treatment of periodontitis: a randomized controlled clinical trial

OBJECTIVES

In this clinical study, we aim to evaluate the effectiveness of non-thermal atmospheric pressure plasma (NAPP), which is a novel procedure used in periodontal pocket decontamination adjunctive to non-surgical periodontal treatment (NSPT).

METHODS

The study included 25 systemically healthy periodontitis patients. In the split-mouth design, NAPP application into the pockets, in addition to NSPT, was performed. Clinical periodontal data, gingival crevicular fluid, and subgingival plaque samples of patients were taken before and during the first and third months of treatment. Biochemical assays were conducted using enzyme-linked immunosorbent assay. Analysis of bacteria was performed with polymerase chain reaction method.

RESULTS

There was more clinical attachment level (CAL) gain in the 3rd month in the test group (deep pockets: 3.90 mm, pockets ≥ 5 mm: 2.72 mm) compared to the control group (deep pockets: 3.40 mm, pockets ≥ 5 mm: 2.58 mm) (p < 0.05), but no significant difference between groups in CAL. Clinical periodontal parameters improved in both study groups (p < 0.05). However, the gingival index (GI) and the bleeding on probing (BOP) rate decreased more in the test group (GI: 0.55, BOP: 9.48%, and GI: 0.38, BOP: 8.46% in the 1st and 3rd months, respectively) compared to the control group (GI: 0.68, BOP: 13.43%, and GI: 0.52, BOP: 14.58%) (p < 0.05). In addition, there was no significant difference in probing depth and biochemical markers between groups (p > 0.05). It was observed that NAPP reduced the number of bacteria more than the control group in the 1st and 3rd months.

CONCLUSIONS

It was seen that the single-time NAPP application concurrent with NSPT provided additional CAL gain, elimination of putative periodontopathogens and reduced their recolonization. Longitudinal studies with larger population and longer time are required.

CLINICAL RELEVANCE

NSPT is an effective method for the treatment of periodontitis but bacteria recolonization that causes recurrence of the periodontal disease occurs within a short period. NAPP can reduce the recurrence of periodontal disease by providing better bacterial elimination and should, therefore, be used in maintenance of periodontitis.

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.

Biofilm as a risk factor in implant treatment

This article summarizes the microbiological findings at dental implants, drawing distinctions between the peri-implant microbiome and the periodontal microbiome, and summarizes what is known regarding biofilm as a risk factor for specific stages of implant treatment. Targeted microbial analysis is reviewed as well as the latest results from open-ended sequencing of the peri-implant flora. At this time there remains a lack of consensus for a specific microbial profile that is associated with peri-implantitis, suggesting that there may be other factors which influence the microbiome such as titanium surface dissolution. Therapeutic interventions to address the biofilm are presented at the preoperative, perioperative, and postoperative stages. Evidence supports that perioperative chlorhexidine reduces biofilm-related implant complications and failure. Regular maintenance for dental implants is also shown to reduce peri-implant mucositis and implant failure. Maintenance procedures should aim to disrupt the biofilm without damaging the titanium dioxide surface layer in an effort to prevent further oxidation. Evidence supports the use of glycine powder air polishing as a valuable adjunct to conventional therapies for use at implant maintenance visits. For the treatment of peri-implantitis, nonsurgical therapy has not been shown to be effective, and while surgical intervention is not always predictable, it has been shown to be superior to nonsurgical treatment for decontamination of the implant surface that is not covered by bone.

Titanium particles and ions favor dysbiosis in oral biofilms

OBJECTIVE

To evaluate the effect of titanium (Ti) particles and ions on oral biofilm growth and composition.

BACKGROUND

Particles and ions of Ti released from dental implants can trigger unfavorable biological responses in human cells. However, their effect on oral biofilms composition has not been tested.

METHODS

In this blind in situ study, volunteers wore a palatal appliance containing Ti disks for 7 days to allow biofilm formation. Disks were then collected and biofilms were treated, in vitro, with Ti particles (0.75% and 1%), ions (10 and 20 ppm), or a combination of both (1% particles + 20 ppm ions). Biofilms exposed only to medium was used as control group. After 24 hours, biofilms were collected and analyzed by checkerboard DNA-DNA hybridization. Direct effects of Ti particles and ions on biofilm/cellular morphology were evaluated by transmission electron microscopy (TEM).

RESULTS

Ti particles affected biofilm composition, increasing population of four bacterial species (P < .05), while Ti ions showed higher levels of putative pathogens from the orange complex with reduction in species from the yellow complex (P < .05), compared with control. The combination of particles + ions increased green complex and reduced yellow complex proportions (P < .05). TEM showed clusters of particles agglomerated in extracellular environment, while Ti ions were precipitated in both extracellular and intracellular sites.

CONCLUSIONS

Ti products, especially Ti ions, have the potential to change the microbiological composition of biofilms formed on Ti surfaces. Therefore, the presence of Ti products around dental implants may contribute to microbial dysbiosis and peri-implantitis.

Short-term effects of hyaluronic acid on the subgingival microbiome in peri-implantitis: A randomized controlled clinical trial

BACKGROUND

The aim of our study was to evaluate the effects of a hyaluronic acid (HA) gel at 45 days on the microbiome of implants with peri-implantitis with at least 1 year of loading.

METHODS

A randomized controlled trial was conducted in peri-implantitis patients. Swabs containing the samples were collected both at baseline and after 45 days of treatment. 16S rRNA sequencing techniques were used to investigate the effect of HA gel on the subgingival microbiome.

RESULTS

One hundred and eight samples of 54 patients were analyzed at baseline and after follow-up at 45 days. Three strata with different microbial composition were obtained in the samples at baseline, representing three main microbial consortia associated with peri-implantitis. Stratum 1 did not show any difference for any variable after treatment with HA, whereas in stratum 2, Streptococcus, Veillonella, Rothia, and Granulicatella did decrease (P < 0.05). Similarly, Prevotella and Campylobacter (P < 0.05) decreased in stratum 3 after treatment with HA. Microbial diversity was found to be decreased in stratum 3 (P < 0.05) after treatment with HA compared with the control group, in which an increase was found (P < 0.05).

CONCLUSIONS

HA reduced the relative abundance of peri-implantitis-related microorganisms, especially the early colonizing bacteria, suggesting a specific action during the first stages in the development of the disease. HA did not alter relative abundances of non-oral genera. The use of HA in advanced stages of peri-implantitis resulted in a decrease in microbial alpha diversity, suggesting a protective action of the peri-implant site against bacteria colonization.

Does subgingival bacterial colonization differ between implants and teeth? A systematic review

The aim was of this study was to determine the current weight of evidence for the existence of specific differences between the microbiota of healthy teeth and healthy implants, or of teeth with periodontitis and implants with peri-implantitis. A systematic review was conducted according to the PRISMA statement. The MEDLINE, EMBASE and Cochrane databases were searched up to February 2018 for studies comparing microbiological data of biofilm samples collected from healthy teeth and implants or from teeth with periodontitis and implants with peri-implantitis. The weight of evidence was defined in three categories (strong, moderate and mild/some), according to the difference in number of studies showing statistically significantly higher counts and/or proportions and/or abundance and/or prevalence of microorganisms in health or in disease. Of the 132 articles identified, 8 were included. A wide range of microorganisms were present in different conditions but no microorganisms showed strong, moderate or mild/some evidence for a specific association with either teeth or implants. The results of this systematic review indicated that there is insufficient evidence in the literature to support specific differences between microorganisms colonizing teeth and implants, either in health or in disease.