Antimicrobial peptides as a possible interlink between periodontal diseases and its risk factors: A systematic review

Antimicrobial peptides (AMPs) play a critical role in controlling innate and acquired immune responses. Local dysregulation of AMP is implicated in the pathogenesis of periodontal diseases as a response to periodontal pathogen challenge. Changes in AMP expression also characterize tobacco smoking, diabetes mellitus, obesity and rheumatoid arthritis, which are established risk factors of periodontal diseases, suggesting AMP may act as putative mechanistic links between these. The aim was to evaluate and summarize critically the current evidence pertaining to interrelationships between AMPs, periodontal diseases and selected periodontal disease risk factors. General and theme specific keywords were used to search the PUBMED database for studies relevant to AMP, periodontal diseases, smoking, diabetes mellitus, obesity and rheumatoid arthritis and critically reviewed. A total of 131 abstracts and 119 full text articles were screened for relevance; 13 studies were selected for inclusion after critical review. Local AMP dysregulation characteristic to periodontal diseases appears to occur within a broader landscape of complex systemic immune perturbations independently induced by smoking, metabolic and rheumatoid disease. The nature of these interactions and mechanistic pathways involved are inadequately understood. AMPs could be possible mechanistic interlinks between periodontal diseases and its risk factors. However, such evidence is very limited and more in vivo and in vitro studies are necessary to clarify the nature of such relationships. A greater understanding of AMPs as shared mediators is essential for unraveling their value as therapeutic or biomarker candidates.     

Association between asthma and periodontal disease: A systematic review and meta‐analysis

1 Background

The aim of this systematic review (SR) is to evaluate the association between asthma and periodontal disease.

2 Methods

An electronic search without date or language restrictions was carried out in PubMed/MEDLINE, Cochrane Central Register of Controlled Trials, Web of Science, and LILACS until May 2016. In addition, manual searches and searches of the gray literature were conducted. The search process, data analysis, and quality assessment were performed by two independent reviewing authors. Eligibility criteria included prospective and retrospective cohort studies, case‐controls, and randomized clinical trials.

3 Results

The search and selection process yielded 21 studies, published between 1979 and 2017. The meta‐analysis showed a statistically significant difference for the parameters of gingival bleeding, plaque index, and gingival index for participants with asthma (P < 0.001).

4 Conclusion

Data from this SR strongly suggest the association of asthma with periodontal disease.     

Matrix metalloproteinase‐8 levels in periodontal disease patients: A systematic review

Periodontal disease is characterized as a disorder of the oral microbiota resulting in an immune response which, in turn, leads to the destruction of periodontal tissue. Matrix metalloproteinase‐8 (MMP‐8) has been reported as the major metalloproteinase involved in periodontal disease, being present at high levels in gingival crevicular fluid and salivary fluid (SF). The aim of this systematic review was to evaluate the scientific literature regarding the expression of MMP‐8 in gingival crevicular fluid and SF in patients with periodontal disease, analyzing its validity as a possible biomarker in the diagnosis of periodontal disease. A systematic review of the literature was performed using the PubMed/Medline, CENTRAL and Science Direct databases. Studies concerning the use of MMP‐8 in the diagnosis of periodontal disease that evaluated its effectiveness as a biomarker for periodontal disease were selected. The search strategy provided a total of 6483 studies. After selection, six articles met all the inclusion criteria and were included in the present systematic review. The studies demonstrated significantly higher concentrations of MMP‐8 in patients with periodontal disease compared with controls, as well as in patients presenting more advanced stages of periodontal disease. The findings on higher MMP‐8 concentrations in patients with periodontal disease compared with controls imply the potential adjunctive use of MMP‐8 in the diagnosis of periodontal disease.     

Relationship between periodontal disease and lung cancer: A systematic review and meta-analysis

Periodontal disease (PD), as a chronic bacterial infection, might cause cardiovascular and some other systemic diseases, with recent studies reporting that it exhibits some connection with lung cancer. While studies have shown that poor oral health might increase the risk of lung cancer, the veracity of these reports is questionable. Therefore, this meta-analysis was undertaken to investigate the association between PD and the risk of lung cancer. A search was run in PubMed, EMBASE, MEDLINE, CENTRAL, and ClinicalTrials.gov databases up to January 1, 2020. Cohort and case-control studies investigating the correlation between PD and lung cancer were included. Eligibility assessment and data extraction were conducted independently, and a meta-analysis was performed to synthesize the data. The association between PD, edentulism, and lung cancer was measured by the adjusted hazard ratios (HRs) or odds ratios (ORs) and their 95% confidence intervals (CIs) provided in articles. We employed appropriate effect model in terms of I² (a fixed-effect model for PD and a random-effect model for edentulism) to obtain summary effect estimates. Statistical heterogeneity was investigated by chi-square test and I² statistics. Newcastle-Ottawa Scale (NOS) was used to assess the quality of their method. Six cohort studies (eight references) and two case-control studies, assessed as high-quality, involving 167 256 participants, were included in the review. The summary estimates based on adjusted data showed an association between PD and a significant risk of lung cancer both in cohort studies (HR = 1.40, 95% CI = 1.25-1.58; I² = 8.7%) and case-control studies (OR = 1.51, 95% CI = 1.16-1.98; I² = 36.5%). Similar features were found in the sensitivity analysis and subgroups for six cohort studies, of male only (HR = 1.36, 95% CI = 1.15-2.60), setting the lung cancer incidence as endpoint (HR = 1.39, 95% CI = 1.24-1.57; I² = 23.9%), and adjusting alcohol for multifactorial HR (HR = 1.38, 95% CI = 1.21-1.57; I² = 39.9%). The summary HR for edentulism was 1.93 (95% CI = 1.05-3.57; I² = 55.3%). No obvious publication bias was detected. This systematic review and meta-analysis demonstrated a significant association between PD and the incidence of lung cancer. Further observational studies are required by using standardized measurements to assess the periodontal status and by eliminating confounding factors, such as alcohol and diabetes, to verify such a relationship.     

A systematic review of guided tissue regeneration for periodontal infrabony defects

OBJECTIVES: To systematically review the evidence for efficacy of guided tissue regeneration (GTR) for infrabony defects. BACKGROUND: The evidence for the efficacy of GTR has not yet been systematically appraised. METHODS: We searched for randomised controlled trials of at least 12 months' follow-up comparing GTR with open flap debridement (OFD). Data sources included electronic databases, hand-searched journals and contact with experts. Screening, data abstraction and quality assessment were conducted independently by multiple reviewers. The primary outcome measure was gain in clinical attachment. RESULTS: For attachment level change, the weighted mean difference between GTR alone and open flap debridement was 1.11 mm (95% CI: 0.63-1.59), chi-square for heterogeneity 31.4 (9 df ), P < 0.001) and for GTR + bone substitutes was 1.25 mm (95% CI: 0.89-1.61, chi-square for heterogeneity 0.01 (1 df), P = 0.91). The number of sites needed to treat (NNT) for GTR to achieve one extra site gaining 2 mm or more attachment over open flap debridement was 8 (95% CI: 4-33). Heterogeneity between studies was highly statistically significant for all principal comparisons and could not be explained satisfactorily by sensitivity analyses. CONCLUSIONS: Overall, GTR was more effective than OFD in improving attachment levels. However, there was marked variability between studies and general conclusions about the clinical benefit of GTR are limited by this heterogeneity. Future studies should aim to identify factors associated with achieving consistent benefits over open flap debridement. Open flap surgery should remain the control comparison in these studies.     

Oral lactobacilli in chronic periodontitis and periodontal health: species composition and antimicrobial activity

BACKGROUND/AIMS: Lactobacilli are known to play an important role in the maintenance of health by stimulating natural immunity and contributing to the balance of microflora. However, their role in chronic periodontitis is unclear. We aimed to identify oral lactobacilli in chronic periodontitis and periodontally healthy subjects, and to determine their antimicrobial activity against putative oral pathogens. METHODS: A total of 238 Lactobacillus isolates from the saliva and subgingival sites of 20 chronic periodontitis and 15 healthy subjects were collected. In all, 115 strains were identified using rapid amplified ribosomal DNA restriction analysis. Antimicrobial activity against Streptococcus mutans, Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, and Prevotella intermedia was assessed. RESULTS: Lactobacilli belonging to 10 species were identified. The most prevalent strains in healthy persons were Lactobacillus gasseri and Lactobacillus fermentum and in chronic periodontitis patients, Lactobacillus plantarum. Obligately homofermentatives, particularly L. gasseri, were less prevalent in chronic periodontitis patients compared with healthy subjects (8% vs. 64% for L. gasseri, P < 0.01). Sixty-nine percent of tested lactobacilli inhibited S. mutans, 88% A. actinomycetemcomitans, 82% P. gingivalis and 65% P. intermedia. The strongest antimicrobial activity was associated with Lactobacillus paracasei, L. plantarum, Lactobacillus rhamnosus, and Lactobacillus salivarius. The strains from periodontally healthy patients showed a lower antimicrobial activity against S. mutans than the strains from chronic periodontitis patients. CONCLUSION: The composition of oral lactoflora in chronic periodontitis and healthy subjects differs, with a higher prevalence of homofermentative lactobacilli, particularly L. gasseri, in the latter group. Both homo- and heterofermentative oral lactobacilli suppress the growth of periodontal pathogens, but the antimicrobial properties are strain, species and origin specific.     

Possible association of periodontal disease with oral cancer and oral potentially malignant disorders: a systematic review

Abstract

Background: Periodontitis has been associated with several systemic diseases and medical conditions, including oral cancer (OC). However, most studies reporting an association between OC and periodontal disease have used different clinical and radiographic criteria to define periodontal disease. This review aimed to evaluate the currently available evidence to determine an association between periodontal disease (extension and severity), OC, and oral potentially malignant disorders (OPMDs).

Material and methods: A systematic search of studies published up to August 2018 was performed following the PRISMA guidelines in the electronic databases MEDLINE (PubMed) and COCHRANE (OVID). A methodological evaluation was made using the Strengthening the Reporting of Observational studies in Epidemiology (STROBE) checklist.

Results: Eight studies (case-control, cross-sectional and cohort) were included. An increased clinical attachment loss, plaque index, bleeding on probing, and radiographic bone loss was found in patients with OC and OPMDs. Differences in the methodological characteristics, case definition used for periodontal diseases, and OC location did not allow estimating the odds ratio required to conduct a meta-analysis.

Conclusion: Some studies suggest a positive relationship between periodontal disease, OC, and OPMDs; however, the currently available evidence is insufficient to draw solid conclusions.     

The effects of orthodontic therapy on periodontal health: a systematic review of controlled evidence

BACKGROUND: Orthodontic therapy has been suggested to lead to an improved periodontal status through mechanisms such as increased ease of plaque removal and reduced occlusal trauma. The objective of the authors' systematic review was to compare contemporary orthodontic treatment with no intervention, by means of evaluating periodontal outcomes measured after end of treatment. METHODS: The authors completed electronic searches in eight databases (1980-2006) and hand searches in six dental journals (1980-2006). They extracted data using standardized forms and calculated weighted mean differences. RESULTS: Weak evidence from one randomized study and 11 nonrandomized studies suggested that orthodontic therapy was associated with 0.03 millimeters of gingival recession (95 percent confidence interval [CI], 0.01-0.04), 0.13 mm of alveolar bone loss (95 percent CI, 0.07-0.20) and 0.23 mm of increased pocket depth (95 percent CI, 0.15-0.30) when compared with no treatment. The effects of orthodontic therapy on gingivitis and attachment loss were inconsistent across studies. CONCLUSIONS: This systematic review identified an absence of reliable evidence describing positive effects of orthodontic treatment on periodontal health. The existing evidence suggests that orthodontic therapy results in small detrimental effects to the periodontium.     

A review of the influence of periodontal treatment in systemic diseases

The effects and consequences of periodontal diseases might not be confined to the oral cavity. A great body of evidence has arisen supporting the claim demonstrating an association with several systemic conditions and diseases. With different levels of evidence, an association between periodontal disease and cardiovascular disease, diabetes, psoriasis, rheumatoid arthritis, pregnancy outcomes and respiratory diseases has been established. However, the true nature of this association, if it is causal, still remains elusive. For a better understanding of the complex relationships linking different conditions, interventional studies now begin to focus on the possible outcomes of periodontal treatment in relation to the events, symptoms and biomarkers of several systemic disorders, assessing if periodontal treatment has any impact on them, hopefully reducing their severity or prevalence. Therefore, we proceeded to review the recent literature on the subject, attempting to present a brief explanation of the systemic condition or disease, what proposed mechanisms might give biological plausibility to its association with periodontal disease, and finally and more importantly, what data are currently available pertaining to the effects periodontal treatment may have. Raising awareness and discussing the possible benefits of periodontal treatment on overall systemic health is important, in order to change the perception that periodontal diseases are only limited to the oral cavity, and ultimately providing better and comprehensive care to patients.