Bacterial profiles and proteolytic activity in peri-implantitis versus healthy sites

Microbial profiling of peri-implantitis compared to the periodontal microbiota in health and disease using 16S rRNA sequencing

PURPOSE

The objective of this study was to analyze the microbial profile of individuals with peri-implantitis (PI) compared to those of periodontally healthy (PH) subjects and periodontitis (PT) subjects using Illumina sequencing.

METHODS

Buccal, supragingival, and subgingival plaque samples were collected from 109 subjects (PH: 30, PT: 49, and PI: 30). The V3-V4 region of 16S rRNA was sequenced and analyzed to profile the plaque microbiota.

RESULTS

Microbial community diversity in the PI group was higher than in the other groups, and the 3 groups showed significantly separated clusters in the buccal samples. The PI group showed different patterns of relative abundance from those in the PH and PT groups depending on the sampling site at both genus and phylum levels. In all samples, some bacterial species presented considerably higher relative abundances in the PI group than in the PH and PT groups, including Anaerotignum lactatifermentans, Bacteroides vulgatus, Faecalibacterium prausnitzii, Olsenella uli, Parasutterella excrementihominis, Prevotella buccae, Pseudoramibacter alactolyticus, Treponema parvum, and Slackia exigua. Network analysis identified that several well-known periodontal pathogens and newly recognized bacteria were closely correlated with each other.

CONCLUSIONS

The composition of the microbiota was considerably different in PI subjects compared to PH and PT subjects, and these results could shed light on the mechanisms involved in the development of PI.

The Main Bacterial Communities Identified in the Sites Affected by Periimplantitis: A Systematic Review

(1) Background: Periimplantitis is an infectious condition that affects the periimplant tissue and is of bacterial etiology. However, to date, the exact bacterial flora involved in its occurrence is not known. The aim of this literature review was to summarize the articles published on this topic and to identify the main bacterial species isolated in periimplantitis. (2) Methods: The articles published in three databases were researched: Pubmed, Embase and Web of Science using Prisma guides and combinations of MeSH terms. We selected 25 items from the 980 found by applying the inclusion and exclusion criteria. (3) Results: We quantified the results of the 25 studies included in this review. In general, the most commonly identified bacterial species were Gram-negative anaerobic species, as Prevotella, Streptococcus, Fusobacterium and Treponema. (4) Conclusion: The most frequent bacteria in the periimplantitis sites identified in this review are Gram-negative anaerobic species, also involved in the pathogenesis of the periodontal disease.

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.

Update on minocycline in vitro activity against odontogenic bacteria

Periodontitis, which is a chronic inflammation caused by biofilm from numerous gram-negative and -positive oral bacterial species between gingiva and tooth, is known to have a poor prognosis. Susceptibility of standard strains (19 strains) and clinical isolates (90 strains) of aerobic and anaerobic oral bacteria, including a recently recovered as novel pathogens for periodontitis called Filifactor alocis, was tested to minocycline (MINO) by using the agar dilution method according to the Clinical and Laboratory Standards Institute. MINO is a well-used therapeutic antibiotic for periodontits. In this study, minimum inhibitory concentrations (MICs) of MINO against Aggregatibacter actinomycetemcomitans (n = 1), Porphyromonas gingivalis (n = 5), Prevotella intermedia (n = 1), Tannerella forsythia (n = 1) and F. alocis (n = 1), were 0.12, ≤0.016-0.03, ≤0.016, 0.03, and 2 μg/mL, respectively. MICs range of MINO against clinical isolates (10 isolates each) Streptococcus intermedius, P. gingivalis, P. intermedia, Fusobacterum nucleatum, Parvimonas micra were 0.06-16, ≤0.016-0.03, ≤0.016-1, ≤0.016-0.12, and ≤0.016-0.25 μg/mL, respectively. These results showed that MINO has superior in vitro activities against to known and recent recovered oral bacteria. Moreover, low prevalence in non-susceptible bacteria was observed to MINO.

The Microbiome of Peri-Implantitis: A Systematic Review and Meta-Analysis

This review aimed to systematically compare microbial profiles of peri-implantitis to those of periodontitis and healthy implants. Therefore, an electronic search in five databases was conducted. For inclusion, studies assessing the microbiome of peri-implantitis in otherwise healthy patients were considered. Literature was assessed for consistent evidence of exclusive or predominant peri-implantitis microbiota. Of 158 potentially eligible articles, data of 64 studies on 3730 samples from peri-implant sites were included in this study. Different assessment methods were described in the studies, namely bacterial culture, PCR-based assessment, hybridization techniques, pyrosequencing, and transcriptomic analyses. After analysis of 13 selected culture-dependent studies, no microbial species were found to be specific for peri-implantitis. After assessment of 28 studies using PCR-based methods and a meta-analysis on 19 studies, a higher prevalence of Aggregatibacter actinomycetemcomitans and Prevotella intermedia (log-odds ratio 4.04 and 2.28, respectively) was detected in peri-implantitis biofilms compared with healthy implants. Actinomyces spp., Porphyromonas spp. and Rothia spp. were found in all five pyrosequencing studies in healthy-, periodontitis-, and peri-implantitis samples. In conclusion, the body of evidence does not show a consistent specific profile. Future studies should focus on the assessment of sites with different diagnosis for the same patient, and investigate the complex host-biofilm interaction.

Gram-negative enteric rods/Pseudomonas colonization in mucositis and peri-implantitis of implants restored with cemented and screwed reconstructions: A cross-sectional study

PURPOSE

To evaluate the association between Gram-negative enteric rods and Pseudomonas with mucositis and peri-implantitis, in implants restored with cemented and screw-retained reconstructions.

MATERIALS AND METHODS

Individuals treated with implants, diagnosed with peri-implant mucositis and or peri-implantitis, participated in this study. Microbiota from the implant and the gingival sulcus of two neighboring teeth were also studied. The microorganisms were identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

RESULTS

A total of 52 and 51 implants cemented and screwed restored were evaluated in 31 patients. The presence of Gram-negative enteric rods/Pseudomonas (P = .01) was significantly higher in the cemented restored implants. When the unit of analysis was the implant, the presence of Gram-negative enteric rods/Pseudomonas was associated with cemented restored implants after adjustment for possible confounders (odds ratio [OR] = 3.7; 95% CI, 1.4-10; P = .01); besides, peri-implantitis was statistically significant in the multivariate model (P = .008). Considering the patient as a unit of analysis, peri-implantitis was associated with cemented restored implants (OR = 9.4; 95% CI, 2-46; P = .006); this statistically significant association remained after adjusting for potential confounders (OR = 6.8; 95% CI, 1.3-37; P = .02).

CONCLUSION

The presence of Gram-negative enteric rods/Pseudomonas was associated with cemented restored implants; besides, peri-implantitis was associated with cemented restored implants.

Epidemiology and risk factors of peri-implantitis: A systematic review

The purpose of this systematic review and meta-analysis was to assess the prevalence, incidence and risk factors of peri-implantitis in the current literature. An electronic search was performed to identify publications from January 1980 until March 2016 on 9 databases. The prevalence and incidence of peri-implantitis were assessed in different subgroups of patients and the prevalences were adjusted for sample size (SSA) of studies. For 12 of 111 identified putative risk factors and risk indicators, forest plots were created. Heterogeneity analysis and random effect meta-analysis were performed for selected potential risk factors of peri-implantitis. The search retrieved 8357 potentially relevant studies. Fifty-seven studies were included in the systematic review. Overall, the prevalence of peri-implantitis on implant level ranged from 1.1% to 85.0% and the incidence from 0.4% within 3 years, to 43.9% within 5 years, respectively. The median prevalence of peri-implantitis was 9.0% (SSA 10.9%) for regular participants of a prophylaxis program, 18.8% (SSA 8.8%) for patients without regular preventive maintenance, 11.0% (SSA 7.4%) for non-smokers, 7.0% (SSA 7.0%) among patients representing the general population, 9.6% (SSA 9.6%) for patients provided with fixed partial dentures, 14.3% (SSA 9.8%) for subjects with a history of periodontitis, 26.0% (SSA 28.8%) for patients with implant function time ≥5 years and 21.2% (SSA 38.4%) for ≥10 years. On a medium and medium-high level of evidence, smoking (effect summary OR 1.7, 95% CI 1.25-2.3), diabetes mellitus (effect summary OR 2.5; 95% CI 1.4-4.5), lack of prophylaxis and history or presence of periodontitis were identified as risk factors of peri-implantitis. There is medium-high evidence that patient's age (effect summary OR 1.0, 95% CI 0.87-1.16), gender and maxillary implants are not related to peri-implantitis. Currently, there is no convincing or low evidence available that identifies osteoporosis, absence of keratinized mucosa, implant surface characteristics or edentulism as risk factors for peri-implantitis. Based on the data analyzed in this systematic review, insufficient high-quality evidence is available to the research question. Future studies of prospective, randomized and controlled type including sufficient sample sizes are needed. The application of consistent diagnostic criteria (eg, according to the latest definition by the European Workshop on Periodontology) is particularly important. Very few studies evaluated the incidence of peri-implantitis; however, this study design may contribute to examine further the potential risk factors.

Diversity analysis of subgingival microbial bacteria in peri-implantitis in Uygur population

This study is to investigate the subgingival bacterial diversity and community structure in the Uygur subjects with peri-implantitis.Totally 40 cases of gingival crevicular fluid were collected from Uygur subjects and divided into the Control group (healthy implants) and Case group (peri-implantitis), respectively. DNA was extracted, and the sequencing in the 16SrRNA V4-V5 region was conducted on the Illumina Miseq sequencing platform. The 16SrRNA gene clone library was constructed and analyzed.Totally 733,759 valid tags were obtained from these 40 samples. After comparing with the Silva-16S database by the Uparse software, 263 operational taxonomic unit were finally harvested (135 for the Control group and 128 for the Case group). The differential bacteria between these 2 groups at the phylum, class, order, family, and genus levels were Actinobacteria, Actinomycetes, Pasteurellales, Moraxellaceae, and Acinetobacter, respectively. The dominant genera with significantly different distribution between the Control and Case groups included Vibrio, Campylobacter, Granulicatella, Acinetobacter, Micrococcus, and Moraxella. The α diverstiy analysis based on the chao diversity index showed that there was significant difference in the microbiological diversity between these 2 groups. Principal coordinates analysis analysis indicated significant differences in the bacterial community structure between these 2 groups. Cluster analysis showed higher abundance of Micrococcus in the Case group, while higher abundance of Prevotella in the Control group.There are significant differences in the diversity of subgingival bacteria between the Uygur subjects with healthy implants and peri-implantitis. Moraxella, Micrococcus, and Acinetobacter might represent dominant bacteria genera causing peri-implantitis in the Uygur population.

Microbiota Analysis of Biofilms on Experimental Abutments Mimicking Dental Implants: An In Vivo Model

BACKGROUND

The microbiota colonizing dental implants has been said to be similar to the microbiome surrounding teeth. In the absence of inflammation, a biofilm with pathologic bacteria can cover implant surfaces exposed to the oral cavity, for example, due to a remodeling process. The aim of the present study is to identify microbiota surrounding exposed dental implants in patients with and without a history of periodontitis through a deep-sequencing approach.

METHODS

An experimental abutment with the same surface and structure as a commercially available dental implant was used. Bacterial DNA was isolated, and the 16S ribosomal RNA gene was amplified and sequenced. Multiplexed tag-encoded sequencing of DNA from the samples was performed, and the reads were processed by metagenomic rapid annotation.

RESULTS

A wide variety of bacteria, 96 species, were identified. The most frequently found bacteria were Fusobacterium nucleatum and Prevotella denticola. Some species generally associated with periodontitis were found to a greater extent in patients without a history of periodontitis. Some bacteria that have never been described as part of the oral microbiome were identified in the present sample.

CONCLUSIONS

Analysis of data suggests that the bacteria surrounding exposed dental implants form a diverse microbiome regardless of the periodontal profile of patients. Further research is needed to clarify the role of these microorganisms in the oral environment.

Microbial Profiles and Detection Techniques in Peri-Implant Diseases: a Systematic Review

Objectives

To describe the microbial profiles of peri-implant diseases and the main detection methods.

Material and Methods

A literature search was performed in MEDLINE via PubMed database to identify studies on microbial composition of peri-implant surfaces in humans published in the last 5 years. Studies had to have clear implant status definition for health, peri-implant mucositis and/or peri-implantitis and specifically study microbial composition of the peri-implant sulcus.

Results

A total of 194 studies were screened and 47 included. Peri-implant sites are reported to be different microbial ecosystems compared to periodontal sites. However, differences between periodontal and peri-implant health and disease are not consistent across all studies, possibly due to the bias introduced by the microbial detection technique. New methods non species-oriented are being used to find ‘unexpected’ microbiota not previously described in these scenarios.

Conclusions

Microbial profile of peri-implant diseases usually includes classic periodontopathogens. However, correlation between studies is difficult, particularly because of the use of different detection methods. New metagenomic techniques should be promoted for future studies to avoid detection bias.

Different sealing materials preventing the microbial leakage into the screw-retained implant restorations: an in vitro analysis by DNA checkerboard hybridization

OBJECTIVES

The aim of this controlled in vitro study was to identify and quantify up to 38 microbial species penetrating through the screw-retained implant prostheses with different sealing materials.

MATERIAL AND METHODS

Sixty morse cone implants were restored with single-unit screw-retained prostheses. All the components were randomly divided into five groups (n = 12) according to the proposed materials: (1) polytetrafluoroethylene tape+composite resin; (2) polytetrafluoroethylene tape+gutta-percha; (3) polytetrafluoroethylene tape+light-polymerized provisional composite; (4) cotton pellet+gutta-percha; and (5) cotton pellet+light-polymerized provisional composite. Human saliva was used as contaminant media, and DNA checkerboard hybridization was used to identify and quantify microbial species.

RESULTS

Microbial leakage was observed in all groups: M. salivarium, S. pasteuri, P. nigrescens, and P. melaninogenica were the species presenting the highest values of genome count, prevalence, and proportion within the groups. The total microbial mean counts (×10⁵ , ±SD) were as follows: Group 1 (2.81 ± 0.38), Group 2 (3.41 ± 0.38), Group 3 (6.02 ± 1.48), Group 4 (6.40 ± 1.42), and Group 5 (17.45 ± 1.67). Group 5 showed the higher microbial counts (P < 0.001).

CONCLUSIONS

Moderate to high counts of pathogenic/nonpathogenic species were detected in the inner parts of implants from all groups. The lowest values of microbial counts were recorded for polytetrafluoroethylene tape associated with composite resin or gutta-percha; cotton pellet associated with light-polymerized provisional composite presented the highest microbial counts.