Role of oral bacteria in respiratory infection

The impact of oral diseases on respiratory health and the influence of respiratory infections on the oral microbiome

OBJECTIVE

The objective of this review is to examine the relationship between oral diseases and respiratory health, investigating how oral microbiome disruptions contribute to respiratory tract infections. Additionally, it aims to explore the impact of respiratory disease symptoms and treatments on the oral microbiome.

DATA SOURCES

The literature utilized in this review was sourced from studies focusing on the correlation between oral health and respiratory infections, spanning a period of 40 years. Various databases and scholarly sources were likely consulted to gather relevant research articles, reviews, and clinical studies.

STUDY SELECTION

This review summarizes four decades-long research, providing insights into the intricate relationship between oral and respiratory health. It delves into how oral diseases influence respiratory tract conditions and vice versa. The selection process likely involved identifying studies that addressed the interaction between oral microbiome disruptions and respiratory complications.

CONCLUSION

Oral diseases or poor oral habits have been known to increase the risk of getting respiratory infections. Modern techniques have demonstrated the relationship between oral disease and respiratory tract infections like influenza, chronic obstructive pulmonary diseases, asthma, and Pneumonia. Apart from that, the medications used to treat respiratory diseases affect oral physiological factors like the pH of saliva, and saliva flow rate, which can cause significant changes in the oral microbiome. This review provides regular oral hygiene and care that can prevent respiratory health and respiratory infections.

CLINICAL SIGNIFICANCE

Understanding the intricate relationship between oral health and respiratory infections is crucial for healthcare providers. Implementing preventive measures and promoting good oral hygiene habits can reduce respiratory tract infections and improve overall respiratory health outcomes.

Impaired oral health: a required companion of bacterial aspiration pneumonia

Laryngotracheal aspiration has a widely-held reputation as a primary cause of lower respiratory infections, such as pneumonia, and is a major concern of care providers of the seriously ill orelderly frail patient. Laryngeal mechanical inefficiency resulting in aspiration into the lower respiratory tract, by itself, is not the cause of pneumonia. It is but one of several factors that must be present simultaneously for pneumonia to develop. Aspiration of oral and gastric contentsoccurs often in healthy people of all ages and without significant pulmonary consequences. Inthe seriously ill or elderly frail patient, higher concentrations of pathogens in the contents of theaspirate are the primary catalyst for pulmonary infection development if in an immunocompromised lower respiratory system. The oral cavity is a complex and ever changing eco-environment striving to maintain homogeneity among the numerous microbial communities inhabiting its surfaces. Poor maintenance of these surfaces to prevent infection can result inpathogenic changes to these microbial communities and, with subsequent proliferation, can altermicrobial communities in the tracheal and bronchial passages. Higher bacterial pathogen concentrations mixing with oral secretions, or with foods, when aspirated into an immunecompromised lower respiratory complex, may result in bacterial aspiration pneumonia development, or other respiratory or systemic diseases. A large volume of clinical evidence makes it clear that oral cleaning regimens, when used in caring for ill or frail patients in hospitals and long-term care facilities, drastically reduce the incidence of respiratory infection and death. The purpose of this narrative review is to examine oral health as a required causative companionin bacterial aspiration pneumonia development, and the effectiveness of oral infection control inthe prevention of this disease.

The relationship between oral frailty and oral dysbiosis among hospitalized patients aged older than 50 years

OBJECTIVE

This study aimed to clarify the relationship between oral frailty and oral dysbiosis among hospitalized patients aged ≥ 50 years.

METHODS

A prospective observational study was conducted. Number of teeth, masticatory ability, articulatory oral motor skill, tongue pressure, swallowing pressure, and choking were used to assess oral frailty. Saliva samples were collected from the oral cavity for bacterial culture.

RESULTS

A total 103 in patients enrolled and 53.4% suffered from oral frailty. Oral frailty was found to have a 3.07-fold correlation with the presence of Enterobacterales in the oral cavity (p = 0.037), especially in poor articulatory oral motor skill, which showed at greater risk of Enterobacterales isolated from the oral cavity by 5.58-fold (p = 0.01).

CONCLUSION

Half of hospitalized patients was found to have oral frailty that was related to more Enterobacterales in the oral cavity. This evidence suggests that the enhancement of articulatory oral motor skills may serve as a potential strategy for mitigating the presence of Enterobacterales within the oral cavity.

A comparison of the prevalence of respiratory pathogens and opportunistic respiratory pathogenic profile of 'clean' and 'unclean' removable dental prostheses

OBJECTIVES

To determine and compare the opportunistic respiratory pathogenic index (ORPI) and prevalence of respiratory pathogens between clean and unclean removable prostheses.

METHODS

A cross-sectional study was conducted among 97 removable prosthesis wearers at a teaching dental hospital. Participants' prosthesis hygiene was grouped into clean and unclean. After prosthesis plaque samples were sequenced using the Type IIB Restriction-site Associated DNA Sequencing for Microbiome method, the prevalence was assessed for the presence of respiratory pathogens on each sample. The ORPIs for clean and unclean prostheses were quantified based on the sum of the relative abundance of respiratory pathogenic bacteria in a microbiome using a reference database that contains opportunistic respiratory pathogens and disease-associated information.

RESULTS

A total of 30 opportunistic respiratory pathogens were identified on the removable prostheses. Eighty-one (83.5 %) removable prostheses harboured respiratory pathogenic bacteria. Stenotrophomonas maltophilia (34.0 %), Pseudomonas aeruginosa (27.8 %), and Streptococcus agalactiae (27.8 %) were the top three prevalent respiratory pathogens detected in plaque samples. There was a significantly higher prevalence of respiratory pathogens residing on unclean than clean prostheses (P = 0.046). However, the ORPIs in both groups showed no statistically significant difference (P = 0.516).

CONCLUSIONS

The ORPIs for both clean and unclean prostheses demonstrated a similar abundance of respiratory pathogens. However, the high prevalence of respiratory pathogens residing on unclean prostheses should not be underestimated. Therefore, maintaining good prosthesis hygiene is still important for overall oral and systemic health, even though the direct link between prosthesis cleanliness and reduced abundance of respiratory pathogens has not been established.

CLINICAL SIGNIFICANCE

The association between the prevalence of respiratory pathogens and unclean removable prostheses has been demonstrated and might increase the theoretical risk of respiratory disease development.

The Impact of Peri-Implant Diseases on the General Status of Patients with Cardiovascular Diseases: A Literature Review

BACKGROUND AND OBJECTIVES

The aim of this study is to connect peri-implantitis to cardiovascular diseases, following the association found between periodontitis and cardiovascular conditions in recent years.

MATERIALS AND METHODS

PubMed, Scopus, Web of Science online databases were searched up to June 2023, with the exclusion criteria being research written in a language other than English. The MeSH search items were as follows: ["peri-implant health OR peri-implantitis OR peri-implant mucositis OR peri-implant disease"] AND ["cardiovascular diseases"]. Patient/population (P), intervention (I), comparison (C), outcome (O) framework questions were followed to identify the clinical evidence for the systematic review. Only clinical studies that used a control group to compare the relationship between cardiovascular diseases and peri-implantitis were selected.

RESULTS

A total of 118 studies were identified through electronic search of the keywords. After removing duplicates, there were 76 records to be screened. Upon exclusion of ineligible titles and abstracts, 27 studies remained for evaluation. Finally, 23 studies were excluded for not meeting the inclusion criteria, leaving 4 studies to be included in the qualitative analyses.

CONCLUSIONS

This study found there is a linear association between mucosal/gingival inflammation and carotid intima-media thickness test (c-IMT) values. Peri-implant mucosal inflammation could be a contributor to the vascular disease burden of an individual; further specific clinical studies should be performed in order to demonstrate this connection.

Association between oral microbiome and five types of respiratory infections: a two-sample Mendelian randomization study in east Asian population

Objective

To explore the causal relationship between the oral microbiome and specific respiratory infections including tonsillitis, chronic sinusitis, bronchiectasis, bronchitis, and pneumonia, assessing the impact of genetic variations associated with the oral microbiome.

Methods

Mendelian randomization was used to analyze genetic variations, leveraging data from genome-wide association studies in an East Asian cohort to identify connections between specific oral microbiota and respiratory infections.

Results

Our analysis revealed that Prevotella, Streptococcus, Fusobacterium, Pauljensenia, and Capnocytophaga play crucial roles in influencing respiratory infections. Prevotella is associated with both promoting bronchitis and inhibiting pneumonia and tonsillitis, with a mixed effect on chronic sinusitis. Streptococcus and Fusobacterium show varied impacts on respiratory diseases, with Fusobacterium promoting chronic sinusitis, bronchiectasis, and bronchitis. Conversely, Pauljensenia and Capnocytophaga are linked to reduced bronchitis and tonsillitis, and inhibited pneumonia and bronchitis, respectively.

Discussion

These findings underscore the significant impact of the oral microbiome on respiratory health, suggesting potential strategies for disease prevention and management through microbiome targeting. The study highlights the complexity of microbial influences on respiratory infections and the importance of further research to elucidate these relationships.

Host-derived protease promotes aggregation of Staphylococcus aureus by cleaving the surface protein SasG

Staphylococcus aureus is one of the leading causes of hospital-acquired infections, many of which begin following attachment and accumulation on indwelling medical devices or diseased tissue. These infections are often linked to the establishment of biofilms, but another often overlooked key characteristic allowing S. aureus to establish persistent infection is the formation of planktonic aggregates. Such aggregates are physiologically similar to biofilms and protect pathogens from innate immune clearance and increase antibiotic tolerance. The cell-wall-associated protein SasG has been implicated in biofilm formation via mechanisms of intercellular aggregation but the mechanism in the context of disease is largely unknown. We have previously shown that the expression of cell-wall-anchored proteins involved in biofilm formation is controlled by the ArlRS-MgrA regulatory cascade. In this work, we demonstrate that the ArlRS two-component system controls aggregation, by repressing the expression of sasG by activation of the global regulator MgrA. We also demonstrate that SasG must be proteolytically processed by a non-staphylococcal protease to induce aggregation and that strains expressing functional full-length sasG aggregate significantly upon proteolysis by a mucosal-derived host protease found in human saliva. We used fractionation and N-terminal sequencing to demonstrate that human trypsin within saliva cleaves within the A domain of SasG to expose the B domain and induce aggregation. Finally, we demonstrated that SasG is involved in virulence during mouse lung infection. Together, our data point to SasG, its processing by host proteases, and SasG-driven aggregation as important elements of S. aureus adaptation to the host environment.IMPORTANCEHere, we demonstrate that the Staphylococcus aureus surface protein SasG is important for cell-cell aggregation in the presence of host proteases. We show that the ArlRS two-component regulatory system controls SasG levels through the cytoplasmic regulator MgrA. We identified human trypsin as the dominant protease triggering SasG-dependent aggregation and demonstrated that SasG is important for S. aureus lung infection. The discovery that host proteases can induce S. aureus aggregation contributes to our understanding of how this pathogen establishes persistent infections. The observations in this study demonstrate the need to strengthen our knowledge of S. aureus surface adhesin function and processing, regulation of adhesin expression, and the mechanisms that promote biofilm formation to develop strategies for preventing chronic infections.

The Dutch version of the Oral Health Assessment Tool: Translation and inter-rater reliability among community nurses

OBJECTIVES

Translating the Oral Health Assessment Tool (OHAT) into Dutch and assessing the inter-rater reliability among community nurses.

METHODS

The original version of the OHAT was translated following the five stages of the 'Guidelines for the Process of Cross-Cultural Adaptation'. After a forward and backward translation, consensus on the pre-final version was obtained in an expert panel discussion. This version was pre-tested on its comprehensibility among 31 nurses and hereafter finalized. Then, inter-rater reliability of the OHAT-NL was determined by two trained nurses during oral assessments of 37 care-dependent community-dwelling older people. Intraclass correlation coefficient (ICC) and the Cohen's kappa statistic for individual items were estimated.

RESULTS

Feedback from nurses in the pre-test did lead to minor changes of the OHAT-NL. Inter-rater reliability was good (ICC 0.79; 95% CI 0.63-0.89) on the total score. Agreement on item level ranged from fair to very good, the kappa ranged from 0.36-0.89.

CONCLUSIONS

OHAT is now available in Dutch having good inter-rater reliability among trained community nurses. Future research can further validate the OHAT-NL and develop intervention according to total OHAT-NL scores.

The Microbiota in Long COVID

Interest in the coronavirus disease 2019 (COVID-19) has progressively decreased lately, mainly due to the great effectivity of vaccines. Furthermore, no new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants able to circumvent the protection of these vaccines, while presenting high transmissibility and/or lethality, have appeared. However, long COVID has emerged as a huge threat to human health and economy globally. The human microbiota plays an important role in health and disease, participating in the modulation of innate and adaptive immune responses. Thus, multiple studies have found that the nasopharyngeal microbiota is altered in COVID-19 patients, with these changes associated with the onset and/or severity of the disease. Nevertheless, although dysbiosis has also been reported in long COVID patients, mainly in the gut, little is known about the possible involvement of the microbiota in the development of this disease. Therefore, in this work, we aim to fill this gap in the knowledge by discussing and comparing the most relevant studies that have been published in this field up to this point. Hence, we discuss that the relevance of long COVID has probably been underestimated, and that the available data suggest that the microbiota could be playing a pivotal role on the pathogenesis of the disease. Further research to elucidate the involvement of the microbiota in long COVID will be essential to explore new therapeutic strategies based on manipulation of the microbiota.

Correlation between the presence of tonsilloliths and the bone defects by periodontitis on imaging analysis: a pilot study

BACKGROUND

Very recently, a significant relationship between tonsilloliths and dental plaque-related pathologies was reported using digital panoramic radiographs. Their dynamics over time suggest that tonsilloliths may be in a permanently active phase that functions to remove foreign matter. The aim of the study was to evaluate the relationship between the occurrence of tonsilloliths and the extent of periodontitis.

METHODS

A total of 608 patients who underwent both CT and panoramic radiographs were included in the study. Both of two imaging were retrospectively and independently assessed with respect to the presence of tonsilloliths detected on CT and panoramic radiographs, and bone defects caused by periodontitis detected on panoramic radiographs. The type of retrospective study is case-control. Then, the differences between age groups were evaluated with respect to the degree of bone resorption and its correlation with the presence of tonsilloliths. The relationships between categorical variables were assessed using Pearson's correlation coefficient or Spearman's correlation coefficient.

RESULTS

There was a significant relationship between tonsilloliths on CT and the extent of the bone defect on panoramic radiographs (Spearman's correlation coefficient, r = 0.648, p = 0.043). In addition, there was a significant difference in the extent of the bone defect caused by periodontitis between subjects with and without tonsilloliths in the 60 to 69-year-old group (Mann-Whitney U test, p = 0.025), 70 to 79-year-old group (Mann-Whitney U test, p = 0.002), and 80 to 89-year-old group (Mann-Whitney U test, p = 0.022), but not in other age groups (Mann-Whitney U test: under 9-year-old group, p = 1.000; 10 to 19-year-old group, p = 1.000; 20 to 29-year-old group, p = 0.854; 30 to 39-year-old group, p = 0.191, 40 to 49-year-old group, p = 0.749; 50 to 59-year-old group, p = 0.627; ≥90-year-old group, p = 1.000).

CONCLUSIONS

The presence of tonsilloliths was related to the extent of periodontitis because the structures were responding dynamically.

Home-based oral health program for adults with intellectual disabilities: An intervention study

BACKGROUND

Poor oral health is common in adults with intellectual disabilities leading to risk of mouth and lung infections. Yet, little is known about the benefits of preventative oral health programs.

OBJECTIVE/HYPOTHESIS

This prospective longitudinal experimental mixed methods study evaluated the efficacy of an oral health program aimed at improving knowledge and behaviours in adults with intellectual disabilities living in supported housing.

METHODS

A 90-min training session was provided to residents and their staff at 12 houses (56 residents; 67 staff). Follow-up training sessions (at 1 week, 1,2,3 months) were tailored to the learning abilities, behavioural/physical challenges, and independence of residents. Outcome measures were collected pre, 1, 2 and 3 months (n = 36): dental exam, plaque index, gingival signs, tongue coating index and behavioural rating scale. At 3 months, support workers (n = 10) and residents (n = 19) were interviewed. Residents' interviews were supported by Talking Mats®.

RESULTS

Most residents (94%) required support for oral cares; with 63% fully dependant on their support workers. 24 (63%) residents had significantly improved plaque scores at 3 months (p < .001). Resident interviews were restricted by communication competency but supported interviews indicated positive responses to 3-sided toothbrush 91%, interdental brush/flosser 60%, and mouthwash 100%. Support worker interviews revealed perceived health and social benefits including fresher breath and benefits of routines.

CONCLUSIONS

Oral health programs for adults with intellectual disabilities living in supported housing are well received by staff and residents, leading to changes in oral care routines and measurable changes in oral health.

COVID-19 on Oral Health: A New Bilateral Connection for the Pandemic

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and transmission are generally known to be produced by respiratory droplets and aerosols from the oral cavity (O.C.) of infected subjects, as stated by the World Health Organization. Saliva also retains the viral particles and aids in the spread of COVID-19. Angiotensin-converting enzyme Type 2 (ACE2) and transmembrane serine protease 2 (TMPRSS2) are two of the numerous factors that promote SARS-CoV-2 infection, expressed by O.C. structures, various mucosa types, and the epithelia of salivary glands. A systemic SARS-CoV-2 infection might result from viral replication in O.C. cells. On the other hand, cellular damage of different subtypes in the O.C. might be associated with various clinical signs and symptoms. Factors interfering with SARS-CoV-2 infection potential might represent fertile ground for possible local pharmacotherapeutic interventions, which may confine SARS-CoV-2 virus entry and transmission in the O.C., finally representing a way to reduce COVID-19 incidence and severity.

Modeling longitudinal oral health status and pneumonia risk: secondary data analyses of an integrated dental-medical cohort

BACKGROUND

Mounting evidence indicates potential associations between poor oral health status (OHS) and increased pneumonia risk. Relative pneumonia risk was assessed in the context of longitudinally documented OHS.

METHODS

Electronic medical/dental patient data captured from 2007 through 2019 were retrieved from the integrated health records of Marshfield Clinic Health Systems. Participant eligibility initiated with an assessment of OHS, stratified into the best, moderate, or worst OHS groups, with the additional criterion of 'no pneumonia diagnosis in the past 90 days'. Pneumonia incidence was longitudinally monitored for up to 1 year from each qualifying dental visit. Models were assessed, with and without adjustment for prior pneumonia incidence, adjusted for smoking and subjected to confounding mitigation attributable to known pneumonia risk factors by applying propensity score analysis. Time-to-event analysis and proportional hazard modeling were applied to investigate relative pneumonia risk over time among the OHS groups.

RESULTS

Modeling identified associations between any incident pneumonia subtype and 'number of missing teeth' (p < 0.001) and 'clinically assessed periodontal status' (p < 0.01), which remained significant following adjustment for prior pneumonia incidence and smoking. The hazard ratio (HR) for 'any incident pneumonia' in the best OHS group for 'number of missing teeth' was 0.65, 95% confidence interval (CI) [0.54 - 0.79] (unadjusted) and 0.744, 95% CI [0.61 - 0.91] (adjusted). The HR for 'any incident pneumonia' in the best 'clinically assessed periodontal status' group was 0.72, 95% CI [0.58 - 0.90] (unadjusted) and 0.78, 95% CI [0.62 - 0.97] (adjusted).

CONCLUSION/CLINICAL RELEVANCE

Poor OHS increased pneumonia risk. Proactive attention of medical providers to patient OHS and health literacy surrounding oral-systemic disease association is vital, especially in high-risk populations.

Proof of concept design for a toothbrush with on-board vacuum to reduce oral aspirates

BACKGROUND

Over the course of brushing, aerosolised particles develop in the mouth. In individuals who do not have the ability to expel these oral aspirates, they can be inhaled and cause aspiration pneumonia. This article showcases a novel vacuum toothbrush, termed "ToothVac," and provides findings from its first human trial.

METHODS

The ToothVac device suctions saliva and aspirates during brushing, storing them in a removable reservoir at the bottom of the brush, to minimise the risk of inhalation and subsequent infection. Further descriptions of the various components of the ToothVac are included. This trial involved 18 participants who brushed using the ToothVac with the vacuum suction turned on and then off.

RESULTS

The volume of saliva produced was measured and compared. The ToothVac significantly reduced the amount of saliva that was produced by these participants when brushing.

CONCLUSION

The device has potential clinical potential in that it may reduce the risk of aspiration pneumonia and related lung infections. Potential future research may include clinical trials for specific indications or marketing for oral aspirate removal, as well as optimisation of brush design using injection moulding for scalable manufacturing.

Factors Influencing Microbiota in Modulating Vaccine Immune Response: A Long Way to Go

Vaccine immunogenicity still represents an unmet need in specific populations, such as people from developing countries and "edge populations". Both intrinsic and extrinsic factors, such as the environment, age, and dietary habits, influence cellular and humoral immune responses. The human microbiota represents a potential key to understanding how these factors impact the immune response to vaccination, with its modulation being a potential step to address vaccine immunogenicity. The aim of this narrative review is to explore the intricate interactions between the microbiota and the immune system in response to vaccines, highlighting the state of the art in gut microbiota modulation as a novel therapeutic approach to enhancing vaccine immunogenicity and laying the foundation for future, more solid data for its translation to the clinical practice.

The Immune System Response to Porphyromonas gingivalis in Neurological Diseases

Previous studies have reported an association between oral microbial dysbiosis and the development and progression of pathologies in the central nervous system. Porphyromonas gingivalis (Pg), the keystone pathogen of the oral cavity, can induce a systemic antibody response measured in patients' sera using enzyme-linked immunosorbent assays. The present case-control study quantified the immune system's response to Pg abundance in the oral cavities of patients affected by different central nervous system pathologies. The study cohort included 87 participants: 23 healthy controls (HC), 17 patients with an acute neurological condition (N-AC), 19 patients with a chronic neurological condition (N-CH), and 28 patients with neurodegenerative disease (N-DEG). The results showed that the Pg abundance in the oral cavity was higher in the N-DEG patients than in the HC (p = 0.0001) and N-AC patients (p = 0.01). In addition, the Pg abundance was higher in the N-CH patients than the HCs (p = 0.005). Only the N-CH patients had more serum anti-Pg antibodies than the HC (p = 0.012). The inadequate response of the immune system of the N-DEG group in producing anti-Pg antibodies was also clearly indicated by an analysis of the ratio between the anti-Pg antibodies quantity and the Pg abundance. Indeed, this ratio was significantly lower between the N-DEG group than all other groups (p = 0.0001, p = 0.002, and p = 0.03 for HC, N-AC, and N-CH, respectively). The immune system's response to Pg abundance in the oral cavity showed a stepwise model: the response diminished progressively from the patients affected with an acute condition to the patients suffering from chronic nervous system disorders and finally to the patients affected by neurodegenerative diseases.

Increased odds for COVID-19 infection among individuals with periodontal disease

OBJECTIVES

Periodontal disease has been linked to multiple systemic conditions, but the relationship with COVID-19 still needs to be elucidated. We hypothesized that periodontal disease may be associated with COVID-19 infection.

MATERIALS AND METHODS

This study utilized cross-sectional data to establish the strength of the association between periodontal disease and COVID-19 infection. The University of Florida Health Center's i2b2 patient's registry was used to generate patient counts through ICD-10 diagnostic codes. Univariate descriptive statistics of the patient population and logistic regression to estimate odds ratios of associations between periodontal disease and COVID-19 infection were used for analysis.

RESULTS

Patients with periodontal disease were 4.4 times more likely to be positively diagnosed with COVID-19 than patients without PD. Associations remained similar and robust (P value < 0.0001) after adjustment for age (OR = 4.34; 95% CI, 3.68-5.09), gender (OR = 4.46; 95% CI, 3.79-5.23), and smoking status (OR = 4.77; 95% CI, 4.04-5.59). Associations were smaller but remained robust (P value < 0.0001) after adjusting for race (OR = 2.83; 95% CI, 2.40-3.32), obesity (OR = 2.53; 95% CI, 2.14-2.98), diabetes (OR = 3.32; 95% CI, 2.81-3.90), and cardiovascular disease (OR = 2.68; 95% CI, 2.27-3.14).

CONCLUSIONS

Periodontal disease is significantly associated with increased odds for COVID-19 infection.

CLINICAL RELEVANCE

With the caveat of a cross-sectional study design, these results suggest that periodontal disease may increase the odds for COVID-19 infection.

Research on the Association Between Periodontitis and COPD

Periodontitis is a common chronic bacteria-initiated inflammatory disease that is closely associated with various systemic diseases, including chronic obstructive pulmonary disease (COPD). Periodontitis and COPD share similar risk factors, pathology and microorganisms. Epidemiological and clinical research have shown positive correlation between the two diseases. Individuals with severe periodontitis had a higher risk of developing COPD. Moreover, the relative risk of COPD in severe periodontitis was much higher compared to people without periodontal disease and patients with mild to moderate periodontitis. COPD patients with periodontitis had a higher frequency of COPD exacerbation and periodontal treatment demonstrated some control of COPD. However, the nature of periodontitis affecting COPD still needs further exploration. Periodontitis caused microbial and immune imbalances of the lung through several aspects: (I) under periodontitis status, periodontal pathogens directly caused the lung inflammatory reaction after inhalation and colonization on the lung, (II) periodontitis status promoted the oral colonization of pneumonia-associated pathogens, (III) periodontitis status affected the respiratory epithelium structure and (IV) periodontitis status caused imbalances in neutrophils, macrophages and inflammatory cytokines. In this review, we conclude the association between periodontitis and COPD through several aspects and further discuss the potential mechanism by which periodontitis affects COPD.

Periodontopathogens Porphyromonas gingivalis and Fusobacterium nucleatum and Their Roles in the Progression of Respiratory Diseases

The intricate interplay between oral microbiota and the human host extends beyond the confines of the oral cavity, profoundly impacting the general health status. Both periodontal diseases and respiratory diseases show high prevalence worldwide and have a marked influence on the quality of life for the patients. Accumulating studies are establishing a compelling association between periodontal diseases and respiratory diseases. Here, in this review, we specifically focus on the key periodontal pathogenic bacteria Porphyromonas gingivalis and Fusobacterium nucleatum and dissect their roles in the onset and course of respiratory diseases, mainly pneumonia, chronic obstructive pulmonary disease, lung cancer, and asthma. The mechanistic underpinnings and molecular processes on how P. gingivalis and F. nucleatum contribute to the progression of related respiratory diseases are further summarized and analyzed, including: induction of mucus hypersecretion and chronic airway inflammation; cytotoxic effects to disrupt the morphology and function of respiratory epithelial cells; synergistic pathogenic effects with respiratory pathogens like Streptococcus pneumoniae and Pseudomonas aeruginosa. By delving into the complex relationship to periodontal diseases and periodontopathogens, this review helps unearth novel insights into the etiopathogenesis of respiratory diseases and inspires the development of potential therapeutic avenues and preventive strategies.

Oral care knowledge, attitude and practice among nursing staff in acute hospital settings in Hong Kong

Investigating the oral care delivered by nursing staff in acute hospital setting is having a remarkable shortage within the current literature. This was provoked due to lack of previous performed investigation in the acute hospital setting besides inconsistent existence of a standardized and comprehensive oral care knowledge, attitude and practice (KAP) instrumentation. Therefore, the purpose of this study is to assess the oral care KAP level for inpatients among nursing staff; to identify possible barriers to the provision of oral care; and to identify training preferences to improve the oral care of inpatients, in acute hospital settings in Hong Kong; and to provide standardized comprehensive KAP based assessment tool that would benefit and guide other future studies. In this study, a cross-sectional survey was conducted after a 55-item self-administered structured questionnaire was developed. A modified KAP tool was developed. The tool includes 4 domains: oral care knowledge, attitude, practice, and experience. Nursing staff was recruited from July 2018 to April 2019 via convenience sampling. Either online or printed questionnaires were completed. Proportions of nursing staff with good KAP, as defined by having 60% of the total score in the respective domain, were estimated with 95% confidence intervals (CI). Analysis of covariance was used to compare the mean scores of KAP among different independent variables and identify the factors associated with good KAP. 404 nursing staff were recruited. Approximately 29.5%, 33.7% and 14.9% of the respondents had good oral care knowledge, attitude and practice, respectively, and 53.2% of the respondents had unpleasant oral care experience. Better oral care practice was associated with higher levels of oral care knowledge (β = 0.1) and oral care attitude (β = 0.3). To conclude: nursing staff in acute hospital settings reported low levels of oral care KAP with variations between the RN, EN and HCA. This study adds to the literature the association between oral care unpleasant experiences and the oral care practice, as well as oral care knowledge and attitude which also in turns associated with practice. The developed standardised tool could be applied for future studies. Recommendations on the future research, training and practices were made.

Oral bacterial composition associated with lung function and lung inflammation in a community-based Norwegian population

BACKGROUND

The oral cavity is the gateway to the bacteria community in the lung. Disruption of the symbiotic balance of the oral microbiota has been associated with respiratory diseases. However, little is known about the relationship between oral bacteria and respiratory outcomes in the general population. We aimed to describe the associations between oral bacteria, lung function, and lung inflammation in a community-based population.

METHODS

Oral (gingival) samples were collected concurrently with spirometry tests in 477 adults (47% males, median age 28 years) from the RHINESSA study in Bergen, Norway. Bacterial DNA from the 16S rRNA gene from gingival fluid were sequenced by Illumina^®MiSeq. Lung function was measured using spirometry and measurement of fractional exhaled nitric oxide (FeNO) were performed to examine airway inflammation. Differential abundance analysis was performed using ANCOM-BC, adjusting for weight, education, and smoking.

RESULTS

The abundance of the genera Clostridiales, Achromobacter, Moraxella, Flavitalea and Helicobacter were significantly different among those with low FEV₁ (< lower limit of normal (LLN)) as compared to normal FEV₁ i.e. ≥ LLN. Twenty-three genera differed in abundance between among those with low FVC < LLN as compared to normal FEV₁ ≥ LLN. The abundance of 27 genera from phyla Actinobacteria, Bacteroidetes, Firmicutes, Proteobacteria and Sacchribacteria differed significantly between elevated FeNO levels (≥ 50 ppb) compared to FeNO ≤ 25 ppb.

CONCLUSION

Oral bacterial composition was significantly different for those with low FEV or FVC as compared to those with normal lung function equal to or higher than LLN. Differential bacterial composition was also observed for elevated FeNO levels.

Subgingival microbial diversity and respiratory decline: A cross-sectional study

AIM

To investigate whether there is an association between subgingival microbial diversity and reduced respiratory function.

MATERIALS AND METHODS

A group of dentate 58-72-year-old men in Northern Ireland had a comprehensive periodontal examination including subgingival plaque sampling. DNA was extracted from plaque samples and the V1-V3 regions of the 16S rRNA gene were analysed by high-throughput sequencing and a microbial diversity index (MDI) was derived. Spirometry measurements were made using a wedge bellows spirometer. The primary outcome variable of interest was the percentage of predicted forced expiratory volume in 1 s (% predicted FEV1 ). Analysis included multiple linear regression with adjustment for various confounders.

RESULTS

Five-hundred and seven men were included in the analysis. The mean age was 63.6 years (SD = 3.1). Of these, 304 (60.0%) men had no or mild periodontitis, 105 (20.7%) had moderate periodontitis and 98 (19.3%) had severe periodontitis. Multiple linear regression analysis showed that a one unit increase in MDI was associated with a 0.71% loss (95% confidence interval: 0.06%-1.35%; p = .03) in % predicted FEV1 after adjustment for all confounders.

CONCLUSIONS

In this group of dentate men from Northern Ireland, subgingival microbial diversity was associated with reduced respiratory function.

Association between chronic obstructive pulmonary disease and periodontal disease: a systematic review and meta-analysis

Objectives

Studies have suggested contradictory results on the relationship between chronic obstructive pulmonary disease (COPD) and periodontal disease (PD). The aim of this study was to determine whether PD increased the risk of COPD and COPD-related clinical events.

Design

A systematic review and meta-analysis.

Data sources

PubMed, Ovid EMBASE and Ovid CENTRAL were searched from inception to 22 February 2023.

Eligibility criteria for studies

We included trials and observational studies evaluating association of PD with the risk of COPD or COPD-related events (exacerbation and mortality), with statistical adjustment for smoking.

Data extraction and synthesis

Two investigators independently extracted data from selected studies using a standardised Excel file. Quality of studies was evaluated using the Newcastle-Ottawa Scale. OR with 95% CI was pooled in a random-effect model with inverse variance method.

Results

22 observational studies with 51 704 participants were included. Pooled analysis of 18 studies suggested that PD was weakly associated with the risk of COPD (OR: 1.20, 95% CI 1.09 to 1.32). However, in stratified and subgroup analyses, with strict adjustment for smoking, PD no longer related to the risk of COPD (adjusting for smoking intensity: OR: 1.14, 95% CI 0.86 to 1.51; smokers only: OR: 1.46, 95% CI 0.92 to 2.31; never smokers only: OR: 0.93, 95% CI 0.72 to 1.21). Moreover, PD did not increase the risk of COPD-related exacerbation or mortality (OR: 1.18, 95% CI 0.71 to 1.97) in the pooled result of four studies.

Conclusions

This study demonstrates PD confers no risk for COPD and COPD-related events when strictly adjusted by smoking. Large-scale prospective cohort studies with control of potential confounding factors are warranted to validate the present findings.

Investigation of the cleaning performance of commercial orthodontic cleaning tablets regarding biofilm removal on PMMA test specimens : An ex vivo study

PURPOSE

The purpose of this ex vivo study was to compare the cleaning performance of three commercially available orthodontic cleaners on polymethyl methacrylate (PMMA) test specimens covered with biofilm.

METHODS

Twenty subjects wore an individually manufactured vacuum-formed maxillary splint with four integrated PMMA test specimens for 7 days. The four test specimens were located on the buccal surfaces of the maxillary molars. After a 7-day wearing period, the PMMA test specimens colonized by biofilm were divided into two halves. One half was placed in 150 ml of tap water or in 150 ml of cleaning solution of the cleaners Retainer Brite® (Dentsply International Raintree Essix, Sarasota, FL, USA), Kukis® Xpress (Reckitt Benckiser, Heidelberg, Germany) or Dontodent (Propack, Heidelberg, Germany) while the other half remained uncleaned. The modified o‑phthaldialdehyde (OPA) method was used to determine the amount of protein on both halves of the test specimens. The difference was tested for significance as a measure of the cleaning effect using a paired sample t‑test.

RESULTS

The cleaning performance of the three orthodontic cleaners was higher than the cleaning performance of tap water (mean 25.9 ± 6.5%). While Retainer Brite® (mean 54.5 ± 7.1%) removed significantly more biofilm than Dontodent (mean 41.5 ± 9.2%, p < 0.001) and Kukis® Xpress (mean 39.9 ± 11.5%, p < 0.001), there was no significant difference in the cleaning performance between Kukis® Xpress and Dontodent (p = 1).

CONCLUSION

Seven-day-old biofilm is only removed partially by the investigated orthodontic cleaners, so that they are not suitable as the only measure for removing established biofilms.

Poor Oral Health in the Etiology and Prevention of Aspiration Pneumonia

Aspiration pneumonia (AP), inflammation of the lung parenchyma initiated by aspirated microorganisms into the lower airways from proximal sites, including the oral cavity, is prevalent in, and problematic for, the elderly, especially those in institutions, and for those with several important risk factors. Many factors influence the pathogenesis of AP, including dysphagia, poor oral hygiene, diminished host defense, and underlying medical conditions. This article reviews the epidemiology, microbiology, pathogenesis, and prevention of AP, focusing on the role of poor oral health as a risk factor for, and on dental care for the prevention and management of, this important infection.

Aggregatibacter actinomycetemcomitans infection in a 15-year-old boy with pulmonary empyema: a case report and review of literature

BACKGROUND

Aggregatibacter actinomycetemcomitans (Aa), previously known as Actinobacillus actinomycetemcomitans, is a slow-growing Gram-negative coccobacillus, member of the HACEK group of bacteria colonizing oral flora. Besides causing infectious diseases in the oral cavity such as dental caries and periodontitis, it is responsible for severe extra-oral infections secondary to hematogenous spread or aspiration, such as endocarditis, soft tissue abscesses and osteomyelitis. The diagnosis depends on prolonged bacterial culture of biological material obtained through biopsy. Aa is susceptible to most antibiotics but complete eradication often requires a long term treatment.

CASE PRESENTATION

We report the case of a 15-year-old previously healthy boy diagnosed with both pulmonary empyema and subphrenic chest wall abscess caused by Aa. He was admitted to our Pediatric Emergency department for evaluation of a right mass associated with marked asthenia and dry cough. After radiological findings etiological diagnosis was made by culture of fluid drainage of pleural empyema. He started empirical antibiotic therapy with intravenous piperacillin/tazobactam, whose sensibility was confirmed by the antibiogram, then, for occurrance of hepatopathy it was switched to ciprofloxacin: the patient almost completely recovered after 6-month therapy.

CONCLUSIONS

Extra-oral infections caused by Aa are extremely rare, especially in children, and not well described yet. To our knowledge, there is only another similar case described in literature. However, the case described in our manuscript represents the only one presenting with pulmonary empyema without involvement of lung parenchyma in children. We also conducted a brief review of published cases of Aa infection in the pediatric population. This case report reminds us the importance of an accurate inspection of the oral cavity during the examination of pediatric patients.

Hardness and surface roughness of differently processed denture base acrylic resins after immersion in simulated gastric acid

STATEMENT OF PROBLEM

The effect of gastric acid on the surface properties of denture base acrylic resin is unknown.

PURPOSE

The purpose of this in vitro study was to evaluate changes in the surface roughness and hardness of denture base acrylic resins after immersion in simulated gastric acid.

MATERIAL AND METHODS

Acrylic resin specimens (n=10) were prepared with 3 different processing techniques (compression-molded, injection-molded, and computer-aided design and computer-aided manufacturing [CAD-CAM] milled) and exposed to either gastric acid or artificial saliva (control). Surface roughness and hardness were measured at baseline (T0) and after 24-hour (T24) and 96-hour (T96) immersion in the solutions. The surface roughness and hardness data were analyzed by 3-way ANOVA and the Tukey HSD test (α=.05).

RESULTS

At T24, the greatest change in surface hardness was observed for compression-molded specimens in gastric acid (P<.05). At T96, changes in hardness values were higher in compression-molded specimens than those in milled specimens (P<.05). Regarding surface roughness, at T24, compression-molded and injection-molded specimens showed higher values than milled specimens in gastric acid (P<.05). Concerning specimens in artificial saliva, compression-molded specimens showed significantly higher changes in roughness than those of the others (P<.05). At T96, injection-molded specimens had the greatest roughness values (P<.05). Among specimens immersed in artificial saliva, milled specimens showed lower roughness values than the injection-molded or compression-molded specimens (P<.05).

CONCLUSIONS

Gastric acid exposure adversely affected the roughness and hardness of all the acrylic resins evaluated. CAD-CAM milled specimens showed better resistance to acid exposure after 24 and 96 hours in terms of roughness and hardness.

The human microbiome: A promising target for lung cancer treatment

Lung cancer is the leading cause of cancer-related deaths worldwide, and insights into its underlying mechanisms as well as potential therapeutic strategies are urgently needed. The microbiome plays an important role in human health, and is also responsible for the initiation and progression of lung cancer through its induction of inflammatory responses and participation in immune regulation, as well as for its role in the generation of metabolic disorders and genotoxicity. Here, the distribution of human microflora along with its biological functions, the relationship between the microbiome and clinical characteristics, and the role of the microbiome in clinical treatment of lung cancer were comprehensively reviewed. This review provides a basis for the current understanding of lung cancer mechanisms with a focus on the microbiome, and contributes to future decisions on treatment management.

Associations between Periodontitis, COVID-19, and Cardiometabolic Complications: Molecular Mechanisms and Clinical Evidence

Periodontitis is a microbially driven, host-mediated disease that leads to loss of periodontal attachment and resorption of bone. It is associated with the elevation of systemic inflammatory markers and with the presence of systemic comorbidities. Coronavirus disease 2019 (COVID-19) is a contagious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Although the majority of patients have mild symptoms, others experience important complications that can lead to death. After the spread of the COVID-19 pandemic, several investigations demonstrating the possible relationship between periodontitis and COVID-19 have been reported. In addition, both periodontal disease and COVID-19 seem to provoke and/or impair several cardiometabolic complications such as cardiovascular disease, type 2 diabetes, metabolic syndrome, dyslipidemia, insulin resistance, obesity, non-alcoholic fatty liver disease, and neurological and neuropsychiatric complications. Therefore, due to the increasing number of investigations focusing on the periodontitis-COVID-19 relationship and considering the severe complications that such an association might cause, this review aims to summarize all existing emerging evidence regarding the link between the periodontitis-COVID-19 axis and consequent cardiometabolic impairments.

Significance of pleural effusion detected by metagenomic next-generation sequencing in the diagnosis of aspiration pneumonia

Objective

Using metagenomic next-generation sequencing (mNGS) to profile the bacterial pathogen of pleural infection in aspiration pneumonia for therapeutic decision-making.

Methods

Collection and analysis of the clinical and laboratory data of aspiration pneumonia patients who underwent mNGS detection of pleural effusion at the Second Hospital of Jilin University from November 2020 and March 2022.

Results

Nine males and one female were included, aged 33 to 69 years. All patients had chest pain, fever, cough, and hypoxemia symptoms; 90% had expectoration. The laboratory tests revealed that all patients had elevated white blood cell, neutrophil, and C-reactive protein (CRP) levels. Furthermore, erythrocyte sedimentation rate (ESR) increased in 8 patients, and procalcitonin increased in only one patient. Chest CT indicated different degrees of lobar pneumonia and pleural effusion in all patients, and biochemical results implied exudative effusion according to Light criteria. Most routine culture results were negative. Among bacteria identified by mNGS, Fusobacterium nucleatum (n=9) was the most common, followed by Parvimonas micra (n=7) and Filifactor alocis (n=6). Three patients underwent surgical treatment after applying targeted antibiotics, thoracic puncture and drainage, and fibrinolytic septum treatment. After the adjusted treatment, the number of white blood cells, neutrophils, and lymphocytes decreased significantly, indicating the eradication of the infection.

Conclusions

Improving the vigilance of atypical people suffering from aspiration pneumonia is essential. The mNGS detection of pleural effusion clarified the microbial spectrum of aspiration pneumonia, allowing targeted antibiotic administration.

Characterizing microbiota and metabolomics analysis to identify candidate biomarkers in lung cancer

BACKGROUND

Lung cancer is the leading malignant disease and cause of cancer-related death worldwide. Most patients with lung cancer had insignificant early symptoms so that most of them were diagnosed at an advanced stage. In addition to factors such as smoking, pollution, lung microbiome and its metabolites play vital roles in the development of lung cancer. However, the interaction between lung microbiota and carcinogenesis is lack of systematically characterized and controversial. Therefore, the purpose of this study was to excavate the features of the lung microbiota and metabolites in patients and verify potential biomarkers for lung cancer diagnosis.

METHODS

Lung tissue flushing solutions and bronchoalveolar lavage fluid samples came from patients with lung cancer and non-lung cancer. The composition and variations of the microbiota and metabolites in samples were explored using muti-omics technologies including 16S rRNA amplicon sequencing, metagenomics and metabolomics.

RESULTS

The metabolomics analysis indicated that 40 different metabolites, such as 9,10-DHOME, sphingosine, and cysteinyl-valine, were statistically significant between two groups (VIP > 1 and P < 0.05). These metabolites were significantly enriched into 11 signal pathways including sphingolipid, autophagy and apoptosis signaling pathway (P < 0.05). The analysis of lung microbiota showed that significant changes reflected the decrease of microbial diversity, changes of distribution of microbial taxa, and variability of the correlation networks of lung microbiota in lung cancer patients. In particular, we found that oral commensal microbiota and multiple probiotics might be connected with the occurrence and progression of lung cancer. Moreover, our study found 3 metabolites and 9 species with significantly differences, which might be regarded as the potential clinical diagnostic markers associated with lung cancer.

CONCLUSIONS

Lung microbiota and metabolites might play important roles in the pathogenesis of lung cancer, and the altered metabolites and microbiota might have the potential to be clinical diagnostic markers and therapeutic targets associated with lung cancer.

Is Periodontitis a Risk Factor for Lung Cancer? A Meta-Analysis and Detailed Review of Mechanisms of Association

Background

Numerous studies have explored the correlation of periodontal disease (PD) with the risk of lung cancers, but the findings were inconsistent. Therefore, we did a meta-analysis to ascertain the correlation of PD with the risk of incident lung cancer.

Methods

The authors searched relevant studies in databases (PubMed, Web of Science, Scopus, Embase, and MEDLINE) till November 2020. We registered the study at the International database of Prospectively Registered Systemic Reviews under the CRD42020198119. The summary relative risk (RR) along with a 95% confidence interval (CI) was calculated using fixed-effects models.

Results

Twelve studies were included in the qualitative synthesis. The pooled analysis revealed that PD was significantly associated with an increased risk of lung cancer (RR 1.71; 95%CI 1.61-1.81; P < 0.01). Subgroup analysis was performed based on gender distribution, geographic location, and type of studies.

Conclusion

From this current evidence, PD is a potential risk factor for the development of lung cancer. The risk for incidence of lung cancer is surged twice in the patients with PD, even though age and smoking are controlled in the studies.

Oral microbiota associated with gingiva of healthy, gingivitis and periodontitis cases

Oral microbes coexist with each other in a symbiotic relationship or as commensals in healthy body. Teeth and oral cavity harbor diverse community of fungi and bacteria. This study focused on bacterial and fungal component of gingiva, where the last occupy little attention. In addition to study the antimicrobial activity of toothpastes, mouth washes and natural oils against microorganisms. Sixty swabs from outer surfaces of gingiva in healthy persons, as well as patients complaining of gingivitis and periodontitis were collected for fungal and bacterial analyses. Sensitivity of the isolated microorganisms to some pharmaceutical preparations and natural oils was also performed. Ten fungal and 9 bacterial species were identified. There is a highly significant variation in the frequency of Klebsiella pneumonia among healthy, gingivitis and periodontitis. Also, Candida tropicalis and cocci bacteria showed significant diversity among the three tested groups. Among pharmaceutical preparations (toothpastes and mouth washes) and natural oils, Paradontax, Hexitol and clove oil showed the best antimicrobial activity against tested fungal and bacterial strains. Although, minimum inhibition concentrations (MICs) of clove oil were high compared to Paradontax and Hexitol, nevertheless, it is highly recommended as both antifungal and antibacterial agent against oral pathogenic microorganisms, because it is a natural compound and nearly devoid of side effects.

Alternative Antibiotics in Dentistry: Antimicrobial Peptides

The rise of antibiotic resistant bacteria due to overuse and misuse of antibiotics in medicine and dentistry is a growing concern. New approaches are needed to combat antibiotic resistant (AR) bacterial infections. There are a number of methods available and in development to address AR infections. Dentists conventionally use chemicals such as chlorohexidine and calcium hydroxide to kill oral bacteria, with many groups recently developing more biocompatible antimicrobial peptides (AMPs) for use in the oral cavity. AMPs are promising candidates in the treatment of (oral) infections. Also known as host defense peptides, AMPs have been isolated from animals across all kingdoms of life and play an integral role in the innate immunity of both prokaryotic and eukaryotic organisms by responding to pathogens. Despite progress over the last four decades, there are only a few AMPs approved for clinical use. This review summarizes an Introduction to Oral Microbiome and Oral Infections, Traditional Antibiotics and Alternatives & Antimicrobial Peptides. There is a focus on cationic AMP characteristics and mechanisms of actions, and an overview of animal-derived natural and synthetic AMPs, as well as observed microbial resistance.

Covid-19 and SARS-CoV-2 infection in periodontology: A narrative review

The present review examined the available evidence on possible involvement of gingival tissues in SARS‐CoV‐2 infection. Gingival tissue possess SARS‐CoV‐2 entry and transmission factors, among them ACE2 (angiotensin‐converting enzyme 2) and TMPRSS2 (transmembrane protease serine 2), which are the principal mediators of the virus cell invasion. Clinical observations reveal SARS‐CoV‐2 RNA in periodontal tissues and crevicular fluid, suggesting that the periodontium may act as an entry point for the virus and/or as a dissemination site. The preliminary observations prove infection potential of gingival crevicular fluid and shed epithelial cells from the periodontium. There are also findings on potential associations between periodontitis and Covid‐19 (coronavirus disease 2019). PubMed and Scopus databases were used to search for suitable keywords such as: SARS‐CoV‐2, Covid‐19, oral virus infection, gingival crevicular fluid, oral mucosa, periodontium, gingiva, ACE2, TMPRSS2, Furin, diagnosis, topical treatment, vaccine and the related words for relevant publications. Data extraction and quality valuation of articles were performed by the author. The review addressed seven major domains: periodontal structures as SARS‐CoV‐2 infection site, the periodontal changes under SARS‐CoV‐2 infection, potential associations between periodontitis and Covid‐19, periodontal oral care in Covid‐19, crevicular fluid as potential transmission factor and preventive measures. The search process in PubMed and Scopus was updated up to 31 March 2022. Finally 68 articles were retrieved for the final analysis, from the initial database searches. According to the inclusion criteria articles in English language without any date restriction were included. The included studies were mostly original articles, and published in 2020 and 2021 with the aim to describe Covid‐19 and SARS‐CoV‐2 infection in periodontology. As a conclusion it can be stated that gingival tissues may play a role in SARS‐CoV‐2 infection.

Nasal Microbiota, Olfactory Health, Neurological Disorders and Aging—A Review

The nasal region is one of the distinct environments for the survival of various microbiota. The human microbial niche begins to inhabit the human body right from birth, and the microbiota survive as commensals or opportunistic pathogens throughout the life of humans in their bodies in various habitats. These microbial communities help to maintain a healthy microenvironment by preventing the attack of pathogens and being involved in immune regulation. Any dysbiosis of microbiota residing in the mucosal surfaces, such as the nasal passages, guts, and genital regions, causes immune modulation and severe infections. The coexistence of microorganisms in the mucosal layers of respiratory passage, resulting in infections due to their co-abundance and interactions, and the background molecular mechanisms responsible for such interactions, need to be considered for investigation. Additional clinical evaluations can explain the interactions among the nasal microbiota, nasal dysbiosis and neurodegenerative diseases (NDs). The respiratory airways usually act as a substratum place for the microbes and can act as the base for respiratory tract infections. The microbial metabolites and the microbes can cross the blood–brain barrier and may cause NDs, such as Parkinson’s disease (PD), Alzheimer’s disease (AD), and multiple sclerosis (MS). The scientific investigations on the potential role of the nasal microbiota in olfactory functions and the relationship between their dysfunction and neurological diseases are limited. Recently, the consequences of the severe acute respiratory syndrome coronavirus (SARS-CoV-2) in patients with neurological diseases are under exploration. The crosstalk between the gut and the nasal microbiota is highly influential, because their mucosal regions are the prominent microbial niche and are connected to the olfaction, immune regulation, and homeostasis of the central nervous system. Diet is one of the major factors, which strongly influences the mucosal membranes of the airways, gut, and lung. Unhealthy diet practices cause dysbiosis in gut microbiota and the mucosal barrier. The current review summarizes the interrelationship between the nasal microbiota dysbiosis, resulting olfactory dysfunctions, and the progression of NDs during aging and the involvement of coronavirus disease 2019 in provoking the NDs.

Oral Dysbiosis and Neurodegenerative Diseases: Correlations and Potential Causations

Biofilms are a heterogenous complex community of vegetative cells and extracellular polymeric substances that can adhere to various surfaces and are responsible for a variety of chronic and acute diseases. The impact of bacterial biofilms on oral and intestinal health is well studied, but the correlation and causations of biofilms and neurodegenerative diseases are still in their infancy. However, the correlations between biofilms and diseases such as Alzheimer’s Disease, Multiple Sclerosis, and even Parkinson’s Disease are starting to demonstrate the role bacterial biofilms have in promoting and exasperating various illnesses. The review article provides insight into the role bacterial biofilms may have on the development and progression of various neurodegenerative diseases and hopefully shine a light on this very important area of research.

Tooth Loss and Risk of Lung Cancer among Urban Chinese Adults: A Cohort Study with Meta-Analysis

Epidemiological evidence on tooth loss and lung cancer risk remains limited, especially for smoking-specific associations. To investigate the association between tooth loss and lung cancer risk by smoking status, we first analyzed data from the Shanghai Men’s Health Study (n = 49,868) and the Shanghai Women’s Health Study (n = 44,309). Cox regression models were applied to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs) for lung cancer risk in relation to tooth loss. We also conducted a meta-analysis to summarize epidemiologic findings to date, incorporating results from the current study and six previously published studies. For 7.3 median follow-up years, 973 incident lung cancer cases (613 men and 360 women) were ascertained. After adjustment for major covariates, tooth loss was associated with an increased risk of lung cancer among men (HR [95% CI] for >10 teeth vs. none = 1.59 [1.21−2.11]) but not among women (0.86 [0.50−1.46]). The positive association was stronger among male current smokers (1.75 [1.26−2.45], p-interaction by smoking status = 0.04). In a meta-analysis incorporating 4052 lung cancer cases and 248,126 non-cases, tooth loss was associated with a 1.64-fold increased risk of developing lung cancer (relative risk [RR, 95% CI] for the uppermost with the lowest category = 1.64 [1.44−1.86]). The positive association was more evident among current smokers (1.86 [1.41−2.46]), but no significant associations were found among never or former smokers. Our findings suggest that tooth loss may be associated with an increased risk of lung cancer, and the association could be modified by smoking status.

Cold Spray: Over 30 Years of Development Toward a Hot Future

Cold Spray (CS) is a deposition process, part of the thermal spray family. In this method, powder particles are accelerated at supersonic speed within a nozzle; impacts against a substrate material triggers a complex process, ultimately leading to consolidation and bonding. CS, in its modern form, has been around for approximately 30 years and has undergone through exciting and unprecedented developmental steps. In this article, we have summarized the key inventions and sub-inventions which pioneered the innovation aspect to the process that is known today, and the key breakthroughs related to the processing of materials CS is currently mastering. CS has not followed a liner path since its invention, but an evolution more similar to a hype cycle: high initial growth of expectations, followed by a decrease in interest and a renewed thrust pushed by a number of demonstrated industrial applications. The process interest is expected to continue (gently) to grow, alongside with further development of equipment and feedstock materials specific for CS processing. A number of current applications have been identified the areas that the process is likely to be the most disruptive in the medium-long term future have been laid down.

A common oral pathogen Porphyromonas gingivalis induces myocarditis in rats

AIM

To evaluate whether Porphyromonas gingivalis (P. gingivalis) inoculation could induce cardiac remodelling in rats.

MATERIALS AND METHODS

The study was conducted on 33 Wistar rats, which were distributed in the following experimental groups: not inoculated; inoculated with 1 × 10⁸ CFU/ml of bacteria; inoculated with 3 × 10⁸ CFU/ml of bacteria. The animals were inoculated at baseline and on the 15th day of follow-up. Blood collection was performed at baseline and 60 min after each inoculation. At 29 days, the animals were subjected to echocardiography and at 30 days to haemodynamic studies before sacrificing them.

RESULTS

Impact of the bacteria was more evident in rats that received higher P. gingivalis concentration. Thus, 3 × 10⁸ CFU/ml of bacteria increased the rectal temperature and water content in the lung as well as myocardial necrosis and fibrosis. P. gingivalis induced the intensification of DNA fragmentation and increased the levels of malondialdehyde, oxidized proteins, and macrophage expression in the myocardium. These findings were associated with lower LV isovolumetric relaxation time, +dP/dt, -dP/dt, and higher end-diastolic pressure.

CONCLUSIONS

P. gingivalis bacteraemia is significantly associated with adverse cardiac remodelling and may play a biological role in the genesis of heart failure.

Oral health status and the etiology and prevention of nonventilator hospital-associated pneumonia

Nonventilator hospital-associated pneumonia has recently emerged as an important preventable hospital-associated infection, and is a leading cause of healthcare-associated infection. Substantial accumulated evidence links poor oral health with an increased risk of pneumonia, which can be caused by bacterial, viral, or fungal pathogens, each with their own distinct mechanisms of transmission and host susceptibility. These infections are frequently polymicrobial, and often include microbes from biofilms in the oral cavity. Evidence documenting the importance of oral care to prevent nonventilator hospital-associated pneumonia is continuing to emerge. Reduction of oral biofilm in these populations will reduce the numbers of potential respiratory pathogens in the oral secretions that can be aspirated, which in turn can reduce the risk for pneumonia. This review summarizes up-to-date information on the role of oral care in the prevention of nonventilator hospital-associated pneumonia.

Oral Pathology in COVID-19 and SARS-CoV-2 Infection-Molecular Aspects

This review article was designed to evaluate the existing evidence related to the molecular processes of SARS-CoV-2 infection in the oral cavity. The World Health Organization stated that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and transmission is produced by respiratory droplets and aerosols from the oral cavity of infected patients. The oral cavity structures, keratinized and non-keratinized mucosa, and salivary glands' epithelia express SARS-CoV-2 entry and transmission factors, especially angiotensin converting enzyme Type 2 (ACE2) and transmembrane serine protease 2 (TMPRSS2). Replication of the virus in cells leads to local and systemic infection spread, and cellular damage is associated with clinical signs and symptoms of the disease in the oral cavity. Saliva, both the cellular and acellular fractions, holds the virus particles and contributes to COVID-19 transmission. The review also presents information about the factors modifying SARS-CoV-2 infection potential and possible local pharmacotherapeutic interventions, which may confine SARS-CoV-2 virus entry and transmission in the oral cavity. The PubMed and Scopus databases were used to search for suitable keywords such as: SARS-CoV-2, COVID-19, oral virus infection, saliva, crevicular fluid, salivary gland, tongue, oral mucosa, periodontium, gingiva, dental pulp, ACE2, TMPRSS2, Furin, diagnosis, topical treatment, vaccine and related words in relevant publications up to 28 December 2021. Data extraction and quality evaluation of the articles were performed by two reviewers, and 63 articles were included in the final review.

Secondary streptococcal infection following influenza

Secondary bacterial infection following influenza A virus (IAV) infection is a major cause of morbidity and mortality during influenza epidemics. Streptococcus pneumoniae has been identified as a predominant pathogen in secondary pneumonia cases that develop following influenza. Although IAV has been shown to enhance susceptibility to the secondary bacterial infection, the underlying mechanism of the viral-bacterial synergy leading to disease progression is complex and remains elusive. In this review, cooperative interactions of viruses and streptococci during co- or secondary infection with IAV are described. IAV infects the upper respiratory tract, therefore, streptococci that inhabit or infect the respiratory tract are of special interest. Since many excellent reviews on the co-infection of IAV and S. pneumoniae have already been published, this review is intended to describe the unique interactions between other streptococci and IAV. Both streptococcal and IAV infections modulate the host epithelial barrier of the respiratory tract in various ways. IAV infection directly disrupts epithelial barriers, though at the same time the virus modifies the properties of infected cells to enhance streptococcal adherence and invasion. Mitis group streptococci produce neuraminidases, which promote IAV infection in a unique manner. The studies reviewed here have revealed intriguing mechanisms underlying secondary streptococcal infection following influenza. This article is protected by copyright. All rights reserved.

Relationships Between Oral Microecosystem and Respiratory Diseases

Oral microecosystem is a very complicated ecosystem that is located in the mouth and comprises oral microbiome, diverse anatomic structures of oral cavity, saliva and interactions between oral microbiota and between oral microbiota and the host. More and more evidence from studies of epidemiology, microbiology and molecular biology is establishing a significant link between oral microecosystem and respiratory diseases. Microbiota settling down in oral microecosystem is known as the main source of lung microbiome and has been associated with the occurrence and development of respiratory diseases like pneumonia, chronic obstructive pulmonary disease, lung cancer, cystic fibrosis lung disease and asthma. In fact, it is not only indigenous oral microbes promote or directly cause respiratory infection and inflammation when inhaled into the lower respiratory tract, but also internal environment of oral microecosystem serves as a reservoir for opportunistic respiratory pathogens. Moreover, poor oral health and oral diseases caused by oral microecological dysbiosis (especially periodontal disease) are related with risk of multiple respiratory diseases. Here, we review the research status on the respiratory diseases related with oral microecosystem. Potential mechanisms on how respiratory pathogens colonize oral microecosystem and the role of indigenous oral microbes in pathogenesis of respiratory diseases are also summarized and analyzed. Given the importance of oral plaque control and oral health interventions in controlling or preventing respiratory infection and diseases, we also summarize the oral health management measures and attentions, not only for populations susceptible to respiratory infection like the elderly and hospitalized patients, but also for dentist or oral hygienists who undertake oral health care. In conclusion, the relationship between respiratory diseases and oral microecosystem has been established and supported by growing body of literature. However, etiological evidence on the role of oral microecosystem in the development of respiratory diseases is still insufficient. Further detailed studies focusing on specific mechanisms on how oral microecosystem participate in the pathogenesis of respiratory diseases could be helpful to prevent and treat respiratory diseases.

Fusobacterium nucleatum exacerbates chronic obstructive pulmonary disease in elastase-induced emphysematous mice

Exacerbation of chronic obstructive pulmonary disease (COPD) is associated with disease progression and increased mortality. Periodontal disease is a risk factor for exacerbation of COPD, but little is known about the role of periodontopathic bacteria in this process. Here, we investigated the effects of intratracheal administration of Fusobacterium nucleatum, a periodontopathic bacteria species, on COPD exacerbation in elastase‐induced emphysematous mice. The administration of F. nucleatum to elastase‐treated mice enhanced inflammatory responses, production of alveolar wall destruction factors, progression of emphysema, and recruitment of mucin, all of which are symptoms observed in patients with COPD exacerbation. Hence, we propose that F. nucleatum may play a role in exacerbation of COPD.

Nrf2 in the Field of Dentistry with Special Attention to NLRP3

The aim of this review article was to summarize the functional implications of the nuclear factor E2-related factor or nuclear factor (erythroid-derived 2)-like 2 (Nrf2), with special attention to the NACHT (nucleotide-binding oligomerization), LRR (leucine-rich repeat), and PYD (pyrin domain) domains-containing protein 3 (NLRP3) inflammasome in the field of dentistry. NLRP3 plays a crucial role in the progression of inflammatory and adaptive immune responses throughout the body. It is already known that this inflammasome is a key regulator of several systemic diseases. The initiation and activation of NLRP3 starts with the oral microbiome and its association with the pathogenesis and progression of several oral diseases, including periodontitis, periapical periodontitis, and oral squamous cell carcinoma (OSCC). The possible role of the inflammasome in oral disease conditions may involve the aberrant regulation of various response mechanisms, not only in the mouth but in the whole body. Understanding the cellular and molecular biology of the NLRP3 inflammasome and its relationship to Nrf2 is necessary for the rationale when suggesting it as a potential therapeutic target for treatment and prevention of oral inflammatory and immunological disorders. In this review, we highlighted the current knowledge about NLRP3, its likely role in the pathogenesis of various inflammatory oral processes, and its crosstalk with Nrf2, which might offer future possibilities for disease prevention and targeted therapy in the field of dentistry and oral health.

Nitinol Type Alloys General Characteristics and Applications in Endodontics

A very extensive literature review presents the possibilities and needs of using, in endodontics, the alloys commonly known as nitinol. Nitinol, as the most modern group of engineering materials used to develop root canals, is equilibrium nickel and titanium alloys in terms of the elements’ atomic concentration, or very similar. The main audience of this paper is engineers, tool designers and manufacturers, PhD students, and students of materials and manufacturing engineering but this article can also certainly be used by dentists. The paper aims to present a full material science characterization of the structure and properties of nitinol alloys and to discuss all structural phenomena that determine the performance properties of these alloys, including those applied to manufacture the endodontic tools. The paper presents the selection of these alloys’ chemical composition and processing conditions and their importance in the endodontic treatment of teeth. The results of laboratory studies on the analysis of changes during the sterilization of endodontic instruments made of nitinol alloys are also included. The summary of all the literature analyses is an SWOT analysis of strengths, weaknesses, opportunities, and threats, and is a forecast of the development strategy of this material in a specific application such as endodontics.

Identifying oral disease variables associated with pneumonia emergence by application of machine learning to integrated medical and dental big data to inform eHealth approaches

Background

The objective of this study was to build models that define variables contributing to pneumonia risk by applying supervised Machine Learning-(ML) to medical and oral disease data to define key risk variables contributing to pneumonia emergence for any pneumonia/pneumonia subtypes.

Methods

Retrospective medical and dental data were retrieved from Marshfield Clinic Health System's data warehouse and integrated electronic medical-dental health records (iEHR). Retrieved data were pre-processed prior to conducting analyses and included matching of cases to controls by (a) race/ethnicity and (b) 1:1 Case: Control ratio. Variables with >30% missing data were excluded from analysis. Datasets were divided into four subsets: (1) All Pneumonia (all cases and controls); (2) community (CAP)/healthcare associated (HCAP) pneumonias; (3) ventilator-associated (VAP)/hospital-acquired (HAP) pneumonias and (4) aspiration pneumonia (AP). Performance of five algorithms were compared across the four subsets: Naïve Bayes, Logistic Regression, Support Vector Machine (SVM), Multi-Layer Perceptron (MLP) and Random Forests. Feature (input variables) selection and ten-fold cross validation was performed on all the datasets. An evaluation set (10%) was extracted from the subsets for further validation. Model performance was evaluated in terms of total accuracy, sensitivity, specificity, F-measure, Mathews-correlation-coefficient and area under receiver operating characteristic curve (AUC).

Results

In total, 6,034 records (cases and controls) met eligibility for inclusion in the main dataset. After feature selection, the variables retained in the subsets were: All Pneumonia (n = 29 variables), CAP-HCAP (n = 26 variables); VAP-HAP (n = 40 variables) and AP (n = 37 variables), respectively. Variables retained (n = 22) were common across all four pneumonia subsets. Of these, the number of missing teeth, periodontal status, periodontal pocket depth more than 5 mm and number of restored teeth contributed to all the subsets and were retained in the model. MLP outperformed other predictive models for All Pneumonia, CAP-HCAP and AP subsets, while SVM outperformed other models in VAP-HAP subset.

Conclusion

This study validates previously described associations between poor oral health and pneumonia. Benefits of an integrated medical-dental record and care delivery environment for modeling pneumonia risk are highlighted. Based on findings, risk score development could inform referrals and follow-up in integrated healthcare delivery environment and coordinated patient management.

Radiographic Detection of the Relationship between Tonsilloliths and Dental Plaque-Related Pathologies in a Series of Digital Panoramic Radiographs

OBJECTIVE

The purpose of this study was to analyse the prevalence of tonsilloliths and to determine radiographically whether there is a relationship between tonsilloliths and dental plaque-related pathologies in a series of digital panoramic radiographs.

MATERIALS AND METHODS

This retrospective study included digital panoramic radiographs of 859 patients admitted for routine dental examination. The panoramic images were examined for both the presence of tonsilloliths and the number of decayed, missing, restored teeth and apical periodontitis. Periodontal bone loss was also measured in thirds of optimal bone height according to the root length and a percentage of bone loss was obtained for each panoramic radiograph evaluated.

RESULTS

Tonsilloliths were observed in 141 (16.4%) of all individuals. While there was no significant difference regarding the number of decayed teeth and restored teeth between tonsillolith cases (TT) and cases without tonsillolith (TC), the number of missing teeth and apical periodontitis in TT was significantly higher than TC (p: 0.004, p: 0.030, respectively). There was a significant difference between the groups in terms of the mean percentage of bone loss (p: 0.001; p < 0.05). In addition, cases showing bone loss between one-third and two-thirds of the optimal bone height in the TT group (52.5%) were significantly higher than those in TC (45.5%) (p: 0.035; p < 0.05).

CONCLUSION

The relationship between dental plaque-related pathologies and tonsilloliths observed in this retrospective study should be confirmed by computed tomography studies and randomized, prospective, clinical trials conducted in a multidisciplinary manner.

Subcutaneous abscess due to empyema necessitans caused by Porphyromonas gingivalis in a patient with periodontitis

Empyema necessitans is a rare empyema complication characterized by an extension of empyema out of the pleural space into the subcutaneous tissues of the chest wall. We herein report a case of empyema necessitans that presented as a subcutaneous chest wall abscess caused by Porphyromonas gingivalis (P. gingivalis), an important anaerobic periodontal pathogen, in a 74-year-old woman with periodontitis. The patient was admitted to our hospital with a painful soft tissue mass in the chest wall extending from a subpleural lung abscess associated with empyema. Exploratory percutaneous puncture and aspiration of the chest wall mass yielded foul-smelling chocolate-colored pus, which was found to be caused due to infection with P. gingivalis. Treatment with antibacterials resulted in a relapse of empyema necessitans requiring a second admission 1 month later. An additive treatment with surgical open drainage and decortication of the subcutaneous abscess successfully cured the abscess. Physicians must be aware of emphysema necessitans as an etiology of a chest wall mass and should consider periodontitis as a source of infection.