Oral microbial ecology and the role of salivary immunoglobulin A

Akkermansia muciniphila in the Human Gastrointestinal Tract: When, Where, and How?

Akkermansia muciniphila is a mucin-degrading bacterium of the phylum Verrucomicrobia. Its abundance in the human intestinal tract is inversely correlated to several disease states. A. muciniphila resides in the mucus layer of the large intestine, where it is involved in maintaining intestinal integrity. We explore the presence of Akkermansia-like spp. based on its 16S rRNA sequence and metagenomic signatures in the human body so as to understand its colonization pattern in time and space. A. muciniphila signatures were detected in colonic samples as early as a few weeks after birth and likely could be maintained throughout life. The sites where Akkermansia-like sequences (including Verrucomicrobia phylum and/or Akkermansia spp. sequences found in the literature) were detected apart from the colon included human milk, the oral cavity, the pancreas, the biliary system, the small intestine, and the appendix. The function of Akkermansia-like spp. in these sites may differ from that in the mucosal layer of the colon. A. muciniphila present in the appendix or in human milk could play a role in the re-colonization of the colon or breast-fed infants, respectively. In conclusion, even though A. muciniphila is most abundantly present in the colon, the presence of Akkermansia-like spp. along the digestive tract indicates that this bacterium might have more functions than those currently known.

Oral Bacterial and Fungal Microbiome Impacts Colorectal Carcinogenesis

Host's physiology is significantly influenced by microbiota colonizing the epithelial surfaces. Complex microbial communities contribute to proper mucosal barrier function, immune response, and prevention of pathogen invasion and have many other crucial functions. The oral cavity and large intestine are distant parts of the digestive tract, both heavily colonized by commensal microbiota. Nevertheless, they feature different proportions of major bacterial and fungal phyla, mostly due to distinct epithelial layers organization and different oxygen levels. A few obligate anaerobic strains inhabiting the oral cavity are involved in the pathogenesis of oral diseases. Interestingly, these microbiota components are also enriched in gut inflammatory and tumor tissue. An altered microbiota composition - dysbiosis - and formation of polymicrobial biofilms seem to play important roles in the development of oral diseases and colorectal cancer. In this review, we describe the differences in composition of commensal microbiota in the oral cavity and large intestine and the mechanisms by which microbiota affect the inflammatory and carcinogenic response of the host.

Induction of salivary antibody levels in Dutch adolescents after immunization with monovalent meningococcal serogroup C or quadrivalent meningococcal serogroup A, C, W and Y conjugate vaccine

Background

Meningococcal infection starts with colonisation of the upper respiratory tract. Mucosal immunity is important for protection against acquisition and subsequent meningococcal carriage. In this study, we assessed salivary antibody levels against meningococcal serogroup A (MenA), W (MenW) and Y (MenY) after vaccination with a quadrivalent MenACWY conjugated vaccine. We also compared salivary meningococcal serogroup C (MenC) antibody levels after monovalent MenC and quadrivalent MenACWY conjugated vaccination.

Methods

Healthy participants, who had received MenC conjugate vaccine between 14 months and 3 years of age, received a (booster) MenC or MenACWY vaccination at age 10–15 years. MenA-, MenC-, MenW- and MenY-polysaccharide (PS) specific IgG and IgA levels in saliva and serum and PS specific secretory component levels in saliva were measured using the fluorescent-bead-based multiplex immunoassay.

Results

MenACYW vaccination increased salivary PS-specific IgA (2-fold) and IgG levels(>10-fold) for MenA, MenY, and MenW. After one year, salivary IgA levels had returned to baseline levels. Both vaccines induced an increase in salivary MenC-PS specific IgA (>3-fold) and IgG (>100-fold), with higher levels after MenC as compared to MenACWY vaccination. The antibody decay rate of MenC in saliva between one month and one year was similar for both vaccines. The overall correlation between serum and saliva IgA levels was low (R = 0.39, R = 0.58, R = 0.31, and R = 0.36 for MenA, MenC, MenW and MenY, respectively). Serogroup-PS specific IgG levels between serum and saliva correlated better (R ranged from 0.51 to 0.88).

Conclusions

Both primary (MenA, MenY, and MenW) and booster (MenC) parenteral meningococcal conjugate vaccination induced high salivary antibody levels. The strong correlation for MenC, MenW and MenY between saliva and serum IgG levels indicates that saliva might be used as a reliable tool to measure vaccine responses after both primary and booster meningococcal vaccination.

Debunking the Myth of Exercise-Induced Immune Suppression: Redefining the Impact of Exercise on Immunological Health Across the Lifespan

Epidemiological evidence indicates that regular physical activity and/or frequent structured exercise reduces the incidence of many chronic diseases in older age, including communicable diseases such as viral and bacterial infections, as well as non-communicable diseases such as cancer and chronic inflammatory disorders. Despite the apparent health benefits achieved by leading an active lifestyle, which imply that regular physical activity and frequent exercise enhance immune competency and regulation, the effect of a single bout of exercise on immune function remains a controversial topic. Indeed, to this day, it is perceived by many that a vigorous bout of exercise can temporarily suppress immune function. In the first part of this review, we deconstruct the key pillars which lay the foundation to this theory-referred to as the "open window" hypothesis-and highlight that: (i) limited reliable evidence exists to support the claim that vigorous exercise heightens risk of opportunistic infections; (ii) purported changes to mucosal immunity, namely salivary IgA levels, after exercise do not signpost a period of immune suppression; and (iii) the dramatic reductions to lymphocyte numbers and function 1-2 h after exercise reflects a transient and time-dependent redistribution of immune cells to peripheral tissues, resulting in a heightened state of immune surveillance and immune regulation, as opposed to immune suppression. In the second part of this review, we provide evidence that frequent exercise enhances-rather than suppresses-immune competency, and highlight key findings from human vaccination studies which show heightened responses to bacterial and viral antigens following bouts of exercise. Finally, in the third part of this review, we highlight that regular physical activity and frequent exercise might limit or delay aging of the immune system, providing further evidence that exercise is beneficial for immunological health. In summary, the over-arching aim of this review is to rebalance opinion over the perceived relationships between exercise and immune function. We emphasize that it is a misconception to label any form of acute exercise as immunosuppressive, and, instead, exercise most likely improves immune competency across the lifespan.

Oral Dysbiotic Communities and Their Implications in Systemic Diseases

The human body supports the growth of a wide array of microbial communities in various niches such as the oral cavity, gastro-intestinal and urogenital tracts, and on the surface of the skin. These host associated microbial communities include yet-un-cultivable bacteria and are influenced by various factors. Together, these communities of bacteria are referred to as the human microbiome. Human oral microbiome consists of both symbionts and pathobionts. Deviation from symbiosis among the bacterial community leads to “dysbiosis”, a state of community disturbance. Dysbiosis occurs due to many confounding factors that predispose a shift in the composition and relative abundance of microbial communities. Dysbiotic communities have been a major cause for many microbiome related systemic infections. Such dysbiosis is directed by certain important pathogens called the “keystone pathogens”, which can modulate community microbiome variations. One such persistent infection is oral infection, mainly periodontitis, where a wide array of causal organisms have been implied to systemic infections such as cardio vascular disease, diabetes mellitus, rheumatoid arthritis, and Alzheimer’s disease. The keystone pathogens co-occur with many yet-cultivable bacteria and their interactions lead to dysbiosis. This has been the focus of recent research. While immune evasion is one of the major modes that leads to dysbiosis, new processes and new virulence factors of bacteria have been shown to be involved in this important process that determines a disease or health state. This review focuses on such dysbiotic communities, their interactions, and their virulence factors that predispose the host to other systemic implications.

Local growth rules can maintain metabolically efficient spatial structure throughout growth

A ubiquitous feature of bacterial communities is the existence of spatial structures. These are often coupled to metabolism, whereby the spatial organization can improve chemical reaction efficiency. However, it is not clear whether or how a desired colony configuration, for example, one that optimizes some overall global objective, could be achieved by individual cells that do not have knowledge of their positions or of the states of all other cells. By using a model which consists of cells producing enzymes that catalyze coupled metabolic reactions, we show that simple, local rules can be sufficient for achieving a global, community-level goal. In particular, even though the optimal configuration varies with colony size, we demonstrate that cells regulating their relative enzyme levels based solely on local metabolite concentrations can maintain the desired overall spatial structure during colony growth. We also show that these rules can be very simple and hence easily implemented by cells. Our framework also predicts scenarios where additional signaling mechanisms may be required.

The oral microbiome - an update for oral healthcare professionals

For millions of years, our resident microbes have coevolved and coexisted with us in a mostly harmonious symbiotic relationship. We are not distinct entities from our microbiome, but together we form a 'superorganism' or holobiont, with the microbiome playing a significant role in our physiology and health. The mouth houses the second most diverse microbial community in the body, harbouring over 700 species of bacteria that colonise the hard surfaces of teeth and the soft tissues of the oral mucosa. Through recent advances in technology, we have started to unravel the complexities of the oral microbiome and gained new insights into its role during both health and disease. Perturbations of the oral microbiome through modern-day lifestyles can have detrimental consequences for our general and oral health. In dysbiosis, the finely-tuned equilibrium of the oral ecosystem is disrupted, allowing disease-promoting bacteria to manifest and cause conditions such as caries, gingivitis and periodontitis. For practitioners and patients alike, promoting a balanced microbiome is therefore important to effectively maintain or restore oral health. This article aims to give an update on our current knowledge of the oral microbiome in health and disease and to discuss implications for modern-day oral healthcare.

Rational design and evaluation of HBsAg polymeric nanoparticles as antigen delivery carriers

The present work is focused on the development and evaluation of single dose sustained-release Hepatitis B surface antigen (HBsAg) loaded nanovaccine for Hepatitis B. The conventional treatment suffers from repeated administration and hence requires a booster dose. Therefore, polymeric nanovaccine of HBsAg was developed by double emulsion solvent evaporation technique, utilizing central composite design for formulation optimization. The effects of independent variables (like polymer amount, stabilizer concentration, aqueous/organic phase ratio and homogenizer speed) were also studied on critical quality attributes like particle size and entrapment efficiency. Nanovaccine was characterized in terms of physicochemical parameters, release, internalization and in vivo immunological evaluation in BALB/c mice after administration by different routes such as oral, sub-cutaneous, nasal and intramuscular. The designed nanovaccine demonstrated nanometric size with smooth surface, negative zeta potential, maximum entrapment, sustained release and better internalization in macrophage and MRC-5 cell line. The immune-stimulating activity of nanovaccine administered by different routes was evaluated by measuring anti-HBsAg titre like specific immunoglobulin IgG and IgA response and cytokine level (interleukin-2, interferon-Y) measurement. The results indicated that the nanovaccine administered by intramuscular route produced better humoral as well as cellular responses and potential carriers for antigen delivery at single dose administration via intramuscular route.

Low-Level Laser Therapy After Wisdom Teeth Surgery: Evaluation of Immunologic Markers (Secretory Immunoglobulin A and Lysozyme Levels) and Thermographic Examination: Placebo Controlled Study

OBJECTIVE

The goal of this investigation is to analyze the effect of therapeutic low-level laser therapy (LLLT) to have a possibility to check pain and inflammation connected with surgical removal of impacted lower third molars in general anesthesia or even phobia [not accompanied by pain or fear of dental treatment, using immunologic markers-secretory immunoglobulin A (sIgA) and lysozyme]. The healing process was also monitored by infrared thermography.

BACKGROUND DATA

LLLT can accelerate the proliferation phase of healing and decrease the inflammatory reaction, but the effect is not really clear.

MATERIALS AND METHODS

The treatment group comprised 213 impacted third molars (144 laser group and 74 placebo group). Laser radiation (diode laser 830 nm) was applied. The effectivity of laser therapy was evaluated based on immunological tests, that is, before and after treatment with sIgA and lysozyme in nonstimulated saliva. Thermographic examination was performed by infrared camera.

RESULTS

After laser irradiation, the sIgA decreases from 546.91 mg/L (SD 354.58) to 304.91 mg/L (SD 191.96), and in the control group from 602.25 mg/L (SD 343.62) to 425.62 mg/L (SD 220.51); the differences were significant, the lysozyme value being lower. After laser therapy, the laser and placebo sides in the area of the third molars were differed in 0.2°C.

CONCLUSIONS

The 830 nm wavelength penetrates to deep-seated tissues. A positive association was found between concentration of salivary sIgA and lysozyme in the saliva after LLLT application. The deep-seated wounds after wisdom teeth extraction had no effect on temperature rise in the face.

Novel Genes Required for the Fitness of Streptococcus pyogenes in Human Saliva

Streptococcus pyogenes (group A streptococcus [GAS]) causes 600 million cases of pharyngitis each year. Despite this considerable disease burden, the molecular mechanisms used by GAS to infect, cause clinical pharyngitis, and persist in the human oropharynx are poorly understood. Saliva is ubiquitous in the human oropharynx and is the first material GAS encounters in the upper respiratory tract. Thus, a fuller understanding of how GAS survives and proliferates in saliva may provide valuable insights into the molecular mechanisms at work in the human oropharynx. We generated a highly saturated transposon insertion mutant library in serotype M1 strain MGAS2221, a strain genetically representative of a pandemic clone that arose in the 1980s and spread globally. The transposon mutant library was exposed to human saliva to screen for GAS genes required for wild-type fitness in this clinically relevant fluid. Using transposon-directed insertion site sequencing (TraDIS), we identified 92 genes required for GAS fitness in saliva. The more prevalent categories represented were genes involved in carbohydrate transport/metabolism, amino acid transport/metabolism, and inorganic ion transport/metabolism. Using six isogenic mutant strains, we confirmed that each of the mutants was significantly impaired for growth or persistence in human saliva ex vivo. Mutants with an inactivated Spy0644 (sptA) or Spy0646 (sptC) gene had especially severe persistence defects. This study is the first to use of TraDIS to study bacterial fitness in human saliva. The new information we obtained will be valuable for future translational maneuvers designed to prevent or treat human GAS infections. IMPORTANCE The human bacterial pathogen Streptococcus pyogenes (group A streptococcus [GAS]) causes more than 600 million cases of pharyngitis annually worldwide, 15 million of which occur in the United States. The human oropharynx is the primary anatomic site for GAS colonization and infection, and saliva is the first material encountered. Using a genome-wide transposon mutant screen, we identified 92 GAS genes required for wild-type fitness in human saliva. Many of the identified genes are involved in carbohydrate transport/metabolism, amino acid transport/metabolism, and inorganic ion transport/metabolism. The new information is potentially valuable for developing novel GAS therapeutics and vaccine research.

Salivary Proteome Patterns Affecting Human Salt Taste Sensitivity

To investigate the role of perireceptor events in inter-individual variability in salt taste sensitivity, 31 volunteers were monitored in their detection functions for sodium chloride (NaCl) and classified into sensitive (0.6-1.7 mmol/L), medium-sensitive (1.8-6.9 mmol/L), and nonsensitive (7.0-11.2 mmol/L) subjects. Chemosensory intervention of NaCl-sensitive (S⁺) and nonsensitive (S^-) panellists with potassium chloride, ammonium chloride, and sodium gluconate showed the salt taste sensitivity to be specific for NaCl. As no significant differences were found between S⁺ and S^- subjects in salivary sodium and protein content, salivary proteome differences and their stimulus-induced dynamic changes were analyzed by tryptic digestion, iTRAQ labeling, and liquid chromatography-tandem mass spectrometry analysis. Differences in the salivary proteome between S⁺ and S^- subjects were found primarily in resting saliva and were largely independent of the dynamic alterations observed upon salt stimulation. Gene ontology enrichment analysis of key proteins, i.e., immunoglobulin heavy constant y1, myeloblastin, cathepsin G, and kallikrein, revealed significantly increased serine-type endopeptidase activity for the S⁺ group, while the S^- group exhibited augmented cysteine-type endopeptidase inhibitor activity by increased abundances in lipocalin-1 and cystatin-D, -S, and -SN, respectively. As proteases have been suggested to facilitate transepithelial sodium transport by cleaving the y-subunit of the epithelial sodium channel (ENaC) and protease inhibitors have been shown to reduce ENaC-mediated sodium transport, the differentially modulated proteolytic activity patterns observed in vivo for S⁺ and S^- subjects show evidence of them playing a crucial role in affecting human NaCl sensitivity.

Tissue-Specific Immunity at the Oral Mucosal Barrier

The oral mucosal barrier is constantly exposed to a plethora of triggers requiring immune control, including a diverse commensal microbiome, ongoing damage from mastication, and dietary and airborne antigens. However, how these tissue-specific cues participate in the training of immune responsiveness at this site is minimally understood. Moreover, the mechanisms mediating homeostatic immunity at this interface are not yet fully defined. Here we present basic aspects of the oral mucosal barrier and discuss local cues that may modulate and train local immune responsiveness. We particularly focus on the immune cell network mediating immune surveillance at a specific oral barrier, the gingiva - a constantly stimulated and dynamic environment where homeostasis is often disrupted, resulting in the common inflammatory disease periodontitis.

Functional morphology of hummingbird bill tips: their function as tongue wringers

Nectarivores are animals that have evolved adaptations to efficiently exploit floral nectar as the main source of energy in their diet. It is well known that hummingbirds can extract nectar with impressive speed from flowers. However, despite decades of study on nectar intake rates, the mechanism by which feeding is ultimately achieved - the release of nectar from the tongue so that it can pass into the throat and be ingested - has not been elucidated. By using microCT scanning and macro high-speed videography we scrutinized the morphology and function of hummingbird bill tips, looking for answers about the nectar offloading process. We found near the bill tip, in an area of strong lateral compression of internal mandibular width, that the tomia (cutting edges of the bill) are thinner, partially inrolled, and hold forward-directed serrations. Aligned with these structures, a prominent pronglike structure projects upward and forward from the internal mandibular keel. Distal to this mandibular prong, another smaller maxillary prong protrudes downwards from the keel of the palate. Four shallow basins occur at the base of the mandibular prong on the mandibular floor. Of these, two are small basins located proximally and at the sides of the mandibular prong. A third, slightly larger basin is positioned distally to the first two and directly under the maxillary prong. And the fourth basin, the largest, is found more proximally where the bill becomes thicker, as seen from the side. We documented that this group of structures is integrated into the area of the bill where tongue extrusion occurs, and we hypothesize that they function to enhance the nectar release at each lick. We suggest that this "wringer", operated by bill and tongue movements, helps to move nectar towards the throat.

Is salivary IgA level a potential biomarker for immunosuppression in HIV-positive children? A systematic review and meta-analysis

The aim of this systematic review was to determine whether or not assessment of salivary secretory immunoglobulin A (sIgA) levels could be a potential biomarker for immunosuppression in HIV-positive children. The Patient, Exposure, Comparative, Outcome question was "Is sIgA level a potential biomarker for immunosuppression in HIV-positive children?" Electronic and manual literature searches were conducted in indexed databases (MEDLINE, PubMed, EMBASE, ScienceDirect, and SCOPUS databases) up to and including June 2017. The primary outcome was total mean salivary levels of IgA among HIV seropositive and seronegative children (controls). The weighted mean differences (WMD) of outcomes and 95% confidence intervals (CI) for total mean salivary IgA levels were calculated using a random effect model. Six studies were included. Three studies showed significantly lower salivary IgA levels in HIV-infected children compared with controls. Two studies showed comparable IgA levels in HIV infected and controls. One study showed significantly higher levels of salivary IgA in HIV-infected children as compared to controls. Considering the total mean salivary IgA levels among HIV seropositive and seronegative children, a high degree of heterogeneity (Q value = 254.09, P < .0001, I²  = 98.82%) was noticed among both groups. The overall WMD was not significant (WMD = -1.18, 95% CI, -1.91 to -0.44, P = .39). Whether salivary IgA level is a potential biomarker for immunosuppression in HIV-positive children remains debatable because of limited information available in the current literature. Further, high-quality case-control studies with larger sample size and more solid methodological aspects are required.

Green synthesis of silver oxide nanoparticles and its antibacterial activity against dental pathogens

In the present study, the use of silver oxide nanoparticles (Ag₂O NPs) synthesized using Ficus benghalensis prop root extract (FBPRE) as a reducing and stabilizing agent is reported and evaluated for its antibacterial activity against dental bacterial strains. The effects of pH, extract concentration, metal ion concentration, and contact time were studied to confirm the optimum production of Ag₂O NPs. Our results suggest that, by increasing the extract concentration and the time frame, there will be a significant increase in the formation of nanoparticles. The UV-vis adsorption spectra show the absorbance peak in the range of 430 nm, and FTIR spectral peaks indicate that the phytochemicals in the extract are responsible for the formation of the nanoparticles. The HR-TEM image, SAED, and XRD pattern confirmed the morphology (spherical), silver oxide 42.7 nm and silver 51.4 nm, and crystalline nature of the obtained nanoparticles, respectively. The blend of FBPRE and Ag₂O NPs showed excellent antibacterial activities against the two-dental bacteria Streptococcus mutans and Lactobacilli sp. The study results suggest that the blend of synthesized Ag₂O NPS and FBPRE will be useful in tooth paste as a germicidal agent after extensive investigation with animal models.

Salivary Immunoglobulin Gene Expression in Patients with Caries

BACKGROUND:

Immunoglobulins mediate the host’s humoral immune response are expressed in saliva.

AIM:

To quantify the FcαR, FcγRIIB, and FcαμR gene expression in the saliva of Mexican patients with caries in mixed and permanent dentition.

SUBJECTS AND METHODS:

This was a comparative cross-sectional study. mRNA was isolated from 200 μL of saliva following the RNA III Tissue Fresh-frozen protocol of the MagNA Pure LC Instrument 2.0 (Roche Diagnostics GmbH, Nederland BV) and the FcαR, FcαμR and FcγRIIB were quantified through TaqMan Assays.

RESULTS:

One hundred individuals, 50 with mixed dentition and 50 with permanent dentition, were included in the study. Statistically, it was found a significant difference (p = 0.025) in the IgG (FcγRIIB) expression between the studied groups.

CONCLUSION:

Although we confirmed the existence of FcαR, FcγRIIB and FcαμR gene expression in saliva, only a significant difference in the expression of FcγRIIB between the mixed dentition and permanent dentition was found.

Probing the diversity of healthy oral microbiome with bioinformatics approaches

The human oral cavity contains a highly personalized microbiome essential to maintaining health, but capable of causing oral and systemic diseases. Thus, an in-depth definition of “healthy oral microbiome” is critical to understanding variations in disease states from preclinical conditions, and disease onset through progressive states of disease. With rapid advances in DNA sequencing and analytical technologies, population-based studies have documented the range and diversity of both taxonomic compositions and functional potentials observed in the oral microbiome in healthy individuals. Besides factors specific to the host, such as age and race/ethnicity, environmental factors also appear to contribute to the variability of the healthy oral microbiome. Here, we review bioinformatic techniques for metagenomic datasets, including their strengths and limitations. In addition, we summarize the interpersonal and intrapersonal diversity of the oral microbiome, taking into consideration the recent large-scale and longitudinal studies, including the Human Microbiome Project.

Early-life factors affect risk of pain and fever in infants during teething periods

AIM

This longitudinal study aimed to investigate the prevalence of teething-related pain and fever and the early-life factors that may affect the risk of experiencing these disturbances within the first 1.5 years of life.

MATERIALS AND METHODS

Participants were recruited (n = 1033) through the Growing Up in Singapore Towards healthy Outcomes (GUSTO) birth cohort (n = 1237). Interviews were performed tri-monthly regarding the prevalence of teething pain and fever in children from 6 to 18 months of age. Crude and multivariable analyses were conducted using Poisson-log regression models.

RESULTS

Prevalence rates for teething pain and fever were 35.5 and 49.9 % respectively. Multivariable Poisson regression analysis showed maternal second-hand tobacco smoke (SHS) exposure to increase the risk of both pain (mean ratio = 1.35; p = 0.006) and fever (mean ratio = 1.22; p = 0.025), whereas SHS exposure plus active smoking further increased risk of teething pain in the children (mean ratio = 1.89; p = 0.029). Delivery via Caesarean section increased risk of teething pain (mean ratio = 1.27; p = 0.033), while prenatal plasma vitamin D insufficiency lowered such a risk (mean ratio = 0.62; p = 0.012). Compared to Chinese infants, Indian babies exhibited lower risk of teething pain and fever (both p ≤ 0.001).

CONCLUSIONS

Early-life factors such as tobacco smoke exposure and vitamin insufficiency during pregnancy, ethnicity and childbirth via Caesarean section may significantly affect the child's susceptibility to teething-related pain and fever.

CLINICAL RELEVANCE

Knowledge of prevalence and risk factors of teething disturbances may better equip primary caregivers and healthcare professionals to accurately detect teething-related local and/or systemic signs/symptoms and effectively facilitate tobacco cessation among pregnant women.

In Vitro Adherence of Oral Bacteria to Different Types of Tongue Piercings

The purpose of this work was to verify in vitro adherence of E. corrodens and S. oralis to the surface of tongue piercings made of surgical steel, titanium, Bioplast, and Teflon. For this, 160 piercings were used for the count of Colony Forming Units (CFU) and 32 piercings for analysis under scanning electron microscopy. Of these, 96 (24 of each type) were individually incubated in 5 mL of BHI broth and 50 μL of inoculum at 37°C/24 h. The other 96 piercings formed the control group and were individually incubated in 5 mL of BHI broth at 37°C/24 h. Plates were incubated at 37°C/48 h for counting of CFU/mL and data were submitted to statistical analysis (p value <0.05). For E. corrodens, difference among types of material was observed (p < 0.001) and titanium and surgical steel showed lower bacterial adherence. The adherence of S. oralis differed among piercings, showing lower colonization (p < 0.007) in titanium and surgical steel piercings. The four types of piercings were susceptible to colonization by E. corrodens and S. oralis, and bacterial adhesion was more significant in those made of Bioplast and Teflon. The piercings presented bacterial colonies on their surface, being higher in plastic piercings probably due to their uneven and rough surface.

Assessment of the antibacterial, cytotoxic and mutagenic potential of the phenolic-rich hydroalcoholic extract from Copaifera trapezifolia Hayne leaves

Copaifera trapezifolia Hayne occurs in the Atlantic Rainforest, which is considered one of the most important and endangered tropical forests on the planet. Although literature works have described many Copaifera spp., their biological activities remain little known. In the present study, we aimed to evaluate (1) the potential of the hydroalcoholic extract from C. trapezifolia leaves (CTE) to act against the causative agents of tooth decay and apical periodontitis and (2) the cytotoxicity and mutagenicity of CTE to ensure that it is safe for subsequent application. Concerning the tested bacteria, the MIC and the minimum bactericidal concentration of CTE varied between 100 and 400 µg ml-1. The time-kill assay conducted at a CTE concentration of 100 µg ml-1 evidenced bactericidal activity against Porphyromonas gingivalis (ATCC 33277) and Peptostreptococcus micros (clinical isolate) within 72 h. CTE at 200 µg ml-1 inhibited Porphyromonas gingivalis and Peptostreptococcus micros biofilm formation by at least 50 %. A combination of CTE with chlorhexidine dichlorohydrate did not prompt any synergistic effects. The colony-forming assay conducted on V79 cells showed that CTE was cytotoxic at concentrations above 156 µg ml-1. CTE exerted mutagenic effect on V79 cells, but the micronucleus test conducted on Swiss mice and the Ames test did not reveal any mutagenicity. Therefore, the use of standardized and safe extracts could be an important strategy to develop novel oral care products with antibacterial action. These extracts could also serve as a source of compounds for the discovery of new promising biomolecules.

Natural Immunoreactivity of Secretory IgA to Indigenous Strains of Streptococcus mutans From Chinese Spousal Pairs

Background

Dental caries is a well-known biofilm-mediated disease initiated by Streptococcus mutans, which should infect and colonize in a milieu perfused with components of the mucosal immune system. Little is known, however, regarding the relationship between the natural secretory IgA activity and S. mutans of a variety of diverse genotypes.

Objectives

The current study aimed to use spousal pairs to investigate the natural immunoreactivity of salivary secretory IgA to different genotype strains of S. mutans.

Patients and Methods

Indigenous strains were characterized from nine spousal pairs using polymerase reaction chain (PCR) and arbitrarily primed polymerase chain reaction (AP-PCR) by genotype monitoring. Unstimulated submandibular/sublingual secretions were collected and the concentrations of secretory IgA were determined by the enzyme-linked immunosorbent assay (ELISA). Each saliva sample was examined by Western blot to analyze the immunoreactivity of naturally occurring salivary secretory IgA antibodies for his/her own indigenous strain, spouse’s strain and reference strains including S. mutans GS-5 and Ingbritt (C).

Results

The results showed that naturally induced salivary IgA antibodies against S. mutans were present in all subjects. Almost all subjects had the similar individual immunoblotting profiles to different genotype strains.

Conclusions

The current study indicated that the immunoreactivity of secretory IgA might have no direct correlation with the colonization of indigenous flora and rejection of exogenous strains in adults. The relationship of microbes, host and dental caries should be in the light of coevolved microecosystem as a whole, but not caused by one factor alone.

Relative effectiveness of azithromycin in killing intracellular Porphyromonas gingivalis

Invasive infections by Porphyromonas gingivalis are associated with persistent periodontal attachment loss and can be difficult to eliminate by scaling and root planing. Azithromycin (AZM) inhibits P. gingivalis and is actively accumulated by most human cells. We used an in vitro infection model to compare the effectiveness of AZM in killing intracellular P. gingivalis to the combined regimen of amoxicillin (AMX) and metronidazole (MET). Transport of [3H]-AZM by human gingival fibroblasts was characterized. Monolayers of Smulow-Glickman gingival epithelial cells or gingival fibroblasts were infected with P. gingivalis (strain 33277 or W83). After extracellular bacteria were eliminated with teicoplanin, infected cells were treated with therapeutic concentrations of AZM, AMX, or AMX + MET. Viable intracellular bacteria were released by cell lysis and plated on blood agar for enumeration. Antimicrobial activity against planktonic P. gingivalis was also evaluated. While survival of intraepithelial P. gingivalis 33277 was not significantly different after treatment with the three regimens, survival in infected fibroblasts was significantly lower after AZM treatment (65.9 ± 5.5%) compared with AMX (92.2 ± 3.5%) or AMX + MET (79.8 ± 5.2%, P < 0.01). Carnitine, a competitive inhibitor of AZM transport, reduced killing by AZM by ~55% (P < 0.05). Survival of intrafibroblast P. gingivalis W83 was also significantly lower after AZM treatment compared with the other regimens (P < 0.05). At therapeutic concentrations, AZM was significantly more active against intracellular P. gingivalis than against planktonic P. gingivalis (P < 0.0083). Gingival epithelial cells and fibroblasts possess a transport system that accumulates AZM and enhances elimination of intracellular P. gingivalis. Compared with the combination of AMX and MET, AZM was equally effective against intraepithelial P. gingivalis 33277 and significantly more effective against both strains of P. gingivalis from infected gingival fibroblasts. The results suggest that AZM could be a reasonable alternative to the regimen of AMX and MET for periodontal patients who should not take these agents due to known side effects or compliance issues.

Copaifera reticulata oleoresin: Chemical characterization and antibacterial properties against oral pathogens

Oral infections such as periodontitis and tooth decay are the most common diseases of humankind. Oleoresins from different copaifera species display antimicrobial and anti-inflammatory activities. Copaifera reticulata is the commonest tree of this genus and grows abundantly in several Brazilian states, such as Pará, Amazonas, and Ceará. The present study has evaluated the chemical composition and antimicrobial potential of the Copaifera reticulata oleoresin (CRO) against the causative agents of tooth decay and periodontitis and has assessed the CRO cytotoxic potential. Cutting edge analytical techniques (GC-MS and LC-MS) aided the chemical characterization of CRO. Antimicrobial assays included determination of the Minimum Inhibitory Concentration (MIC), determination of the Minimum Bactericidal Concentration (MBC), determination of the Minimum Inhibitory Concentration of Biofilm (MICB50), Time Kill Assay, and Checkerboard Dilution. Conduction of XTT assays on human lung fibroblasts (GM07492-A cells) helped to examine the CRO cytotoxic potential. Chromatographic analyses revealed that the major constituents of CRO were β-bisabolene, trans-α-bergamotene, β-selinene, α-selinene, and the terpene acids ent-agathic-15-methyl ester, ent-copalic acid, and ent-polyalthic acid. MIC and MBC results ranged from 6.25 to 200 μg/mL against the tested bacteria. The time-kill assay conducted with CRO at concentrations between 50 and 100 μg/mL showed bactericidal activity against Fusobacterium nucleatum (ATCC 25586) and Streptococcus mitis (ATCC 49456) after 4 h, Prevotella nigrescens (ATCC 33563) after 6 h, Porphyromonas gingivalis (ATCC 33277) and Lactobacillus casei (clinical isolate) after 12 h, and Streptococcus salivarius (ATCC 25975) and Streptococcus mutans (ATCC 25175) after 18 h. The fractional inhibitory concentration indexes (FICIs) revealed antagonistic interaction for Lactobacillus casei (clinical isolate), indifferent effect for Porphyromonas gingivalis (ATCC 33277), Fusobacterium nucleatum (ATCC 25586), Prevotella nigrescens (ATCC 33563), and Streptococcus salivarius (ATCC 25975), and additive effect for Streptococcus mutans (ATCC 25175) and Streptococcus mitis (ATCC 49456). Treatment of GM07492-A cells with CRO demonstrated that concentrations up to 39 μg/mL significantly reduced cell viability as compared to the negative control, being IC50 equal to 51.85 ± 5.4 μg/mL. These results indicated that CRO plays an important part in the search for novel sources of agents that can act against oral pathogens.

Hyposalivation and Xerostomia: Etiology, Complications, and Medical Management

Saliva is one of the most versatile, multifunctional substances produced by the body and has a critical role in the preservation of the oropharyngeal health. It comprises a serous and mucinous component and is secreted by the major salivary glands. The mucins in the saliva serve to protect and lubricate the hard and soft tissues of the mouth, protecting them from chemical and mechanical damage. Hyposalivation can be managed by various salivary substitutes, peripheral sialagogues, and central sialagogues.

In vitro fabrication of dental filling nanopowder by green route and its antibacterial activity against dental pathogens

The aim of this study was to introduce novel Sn, Cu, Hg, and Ag nanopowders (NPs) and a composite nanopowder (NP) synthesized using Salvia miltiorrhiza Bunge (SM) root extract as a reducing and capping agent to improve the antibacterial property of dental filling materials. All of the NPs obtained were characterized using a scanning transmission electron microscope (STEM), and energy dispersive X-ray (EDX) spectrum imaging was performed to map the elemental distributions of the NP composite. Fourier transform infrared (FTIR) spectroscopy was performed to identify the role of various functional groups in all of the obtained NPs and the phyto-compound responsible for the reduction of various metal ions. The X-ray diffraction (XRD) patterns clearly illustrated the crystalline phase of the synthesized NP. The antibacterial properties of the synthesized Sn, Cu, Hg, Ag, composite NP, SM root extract, and commercial amalgam powder were evaluated. The Cu, composite NP, SM root extract and Ag NP displayed excellent antibacterial activity against dental bacteria Streptococcus mutans and Lactobacillus acidophilus. The results of this study require further evaluation for signs of metal toxicity in appropriate animal models. However, the results are encouraging for the application of metal NPs as suitable alternatives for antibiotics and disinfectants, especially in dental filling materials.

Porphyromonas gingivalis: An Overview of Periodontopathic Pathogen below the Gum Line

Periodontal disease represents a group of oral inflammatory infections initiated by oral pathogens which exist as a complex biofilms on the tooth surface and cause destruction to tooth supporting tissues. The severity of this disease ranges from mild and reversible inflammation of the gingiva (gingivitis) to chronic destruction of connective tissues, the formation of periodontal pocket and ultimately result in loss of teeth. While human subgingival plaque harbors more than 500 bacterial species, considerable research has shown that Porphyromonas gingivalis, a Gram-negative anaerobic bacterium, is the major etiologic agent which contributes to chronic periodontitis. This black-pigmented bacterium produces a myriad of virulence factors that cause destruction to periodontal tissues either directly or indirectly by modulating the host inflammatory response. Here, this review provides an overview of P. gingivalis and how its virulence factors contribute to the pathogenesis with other microbiome consortium in oral cavity.

Evaluation of Salivary Secretory Immunoglobulin A Levels in Diabetic Patients and Association with Oral and Dental Manifestations

OBJECTIVES

Oral and dental manifestations in diabetic patients can arise due to numerous factors, including elevated salivary secretory immunoglobulin A (s-IgA) levels. This study aimed to evaluate s-IgA concentrations in patients with type 2 diabetes mellitus (T2DM) and to investigate the association between s-IgA levels and oral and dental manifestations of T2DM.

METHODS

This cross-sectional descriptive study was carried out between October 2011 and September 2012 in Kerman, Iran, and included 260 subjects (128 patients with T2DM and 132 healthy controls). Unstimulated salivary samples were collected from all subjects and s-IgA levels were determined using the immunoturbidimetric method. The oral cavities and teeth of T2DM patients were evaluated for oral and dental manifestations.

RESULTS

Both diabetic and control subjects with higher concentrations of s-IgA had significantly higher numbers of decayed, missing or filled teeth (DMFT) and periodontal index (PDI) scores (P <0.050). s-IgA levels were significantly higher in subjects with oral candidiasis (P <0.050). Among diabetic patients, significantly higher s-IgA levels were concomitant with xerostomia and denture stomatitis (P ≤0.050). There were no significant differences between s-IgA concentrations and other oral or dental manifestations in either group.

CONCLUSION

Individuals with a greater number of DMFT, a higher PDI score and oral candidiasis had significantly higher s-IgA levels. s-IgA levels were not significantly higher among diabetic patients in comparison to the control group. However, significantly higher s-IgA levels occurred with xerostomia and denture stomatitis in diabetic patients. In addition, s-IgA was significantly higher in patients with uncontrolled diabetes compared to those with controlled diabetes.

Antiasthmatic Inhaled Medications as Favoring Factors for Increased Concentration of Streptococcus Mutans

Introduction:

The negative impact of inhaled antiasthmatic drugs (IAD) on oral health is reflected primarily in the increased incidence of caries in asthmatic children compared to healthy children. It is believed that one of the causes of the increased incidence of caries in asthmatic children is from bronchodilator effect in reduced secretion of saliva. Decreased salivation favors bacterial colonization and studies have shown that the concentration of Streptococcus mutans, a bacterium that has the primary role in the development of caries, is higher in asthmatic than in healthy children.

Material and methods:

The study sample consisted of 200 patients, age from 7-14 years, divided into two groups: control group (n1 = 100) consisted of healthy children and the experimental group consisted of children suffering from asthma (n2 = 100). In both groups of respondents are identified the DMFT values, the concentration of Streptococcus mutans, the amount of stimulated saliva and plaque index value.

Results:

It was found that there are significant differences in the values of plaque index, salivary index and streptococcus mutans between the control and experimental groups (p> 0.05 for each of the examined variables). Those in the control group had significantly higher DMFT index than subjects in the experimental group (p = 0.004).

Conclusion:

IAD does not cause reduced saliva production and thus do not represent a factor favoring increased concentration of Streptococcus mutans.

Oral Microbiota, Periodontal Status, and Osteoporosis in Postmenopausal Females

BACKGROUND

Alterations in hormone levels during menopause decrease bone density and may worsen oral health, favoring the growth of periodontal pathogens, whose detection could improve the diagnosis of periodontitis. The aim of this study is to detect and quantify the main periodontal pathogens in the oral microbiota of postmenopausal females and to explore the relationship between clinical and periodontal parameters.

METHODS

This was an observational cross-sectional study of 76 postmenopausal females. Dental examinations and sampling for microbiologic evaluation were performed, and a history of osteoporosis/osteopenia was collected. Real-time polymerase chain reaction was used for detecting and quantifying Fusobacterium nucleatum (Fn), Aggregatibacter actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), Campylobacter rectus (Cr), and Tannerella forsythia (Tf). The results obtained were subjected to statistical analyses. Statistical significance was defined as P <0.05.

RESULTS

Periodontitis was detected in 77.1% of females with osteoporosis/osteopenia (P >0.05). A significant correlation was found between osteoporosis and missing teeth. T. forsythia and C. rectus were detected in 100% of the samples, Fn and Pg in 98.7%, and Aa in 73.7%.

CONCLUSIONS

Osteoporosis did not influence the prevalence of periodontitis among postmenopausal females. The presence of periodontopathogenic bacteria was not sufficient to confirm disease. A preventive maintenance program for postmenopausal females, particularly osteoporotic females, who are at greater risk of tooth loss, could minimize the potential effects of bone loss on periodontal tissues.

Mucosal immunity and upper respiratory tract symptoms in recreational endurance runners

The present study investigated the effects of a 12-week endurance-training intervention on salivary proteins and upper respiratory tract symptoms (URS) in 25 young men. Saliva samples of 25 recreational male endurance runners (age 34.6 years, body mass index = 23.8 kg·m(-2), peak aerobic capacity = 47.2 mL·kg(-1)·min(-1)) were collected before (PRE) and after (POST) the training intervention, in a fasting state, as well as both before and after a maximal incremental treadmill run. The training consisted of both continuous and interval training sessions, 4-6 times per week based on the polarized training approach. Participants filled in Wisconsin Upper Respiratory Symptom Survey-21 and were retrospectively divided into 2 groups according to whether they reported URS (URS group, n = 13) or not (HEALTHY group, n = 12). Basal salivary immunoglobulin A (sa-sIgA) levels were significantly higher (+70%, p < 0.05) in the HEALTHY group both at PRE and POST whereas no significant differences were observed in salivary immunoglobulin M, salivary immunoglobulin G, lysozyme, or salivary α-amylase activity (sAA). Sa-sIgA concentration at PRE significantly correlated with the number of sick-days (R = -0.755, p < 0.001) in all subjects. The incremental treadmill run acutely increased sAA significantly (p < 0.05) at PRE (200%) and POST (166%) in the HEALTHY group but not in the URS group. This study demonstrated that subjects, who experienced URS during the 12 weeks of progressive endurance training intervention, had significantly lower basal sa-sIgA levels both before and after the experimental endurance training period. In addition to sa-sIgA, acute sAA response to exercise might be a possible determinant of susceptibility to URS in endurance runners.

Acute effects of black currant consumption on salivary flow rate and secretion rate of salivary immunoglobulin a in healthy smokers

The role of saliva in maintaining oral health and homeostasis is based on its physicochemical properties and biological activities of its components, including salivary immunoglobulin A (IgA). Both salivary rates and immunological status of saliva are found to be compromised in smokers. The aim of this study was to investigate the acute time-dependent effect of smoking and black currant consumption on the salivary flow rate (SFR) and salivary IgA secretion rate (sIgA SR) in healthy smokers. SFR, sIgA levels in saliva, and sIgA SRs were determined in healthy smokers (n=8) at eight times of assessment within three consecutive interventions: at the baseline; 5, 30, and 60 min after smoking; 5, 30, and 60 min after black currant consumption (100 g), followed by smoking; and 5 min after black currant consumption. Smoking induced a significant delayed effect on SFR measured 60 min after smoking (P=.03), while black currant consumption preceding smoking prevented that effect. Salivary IgA concentrations and sIgA flow rates were not acutely influenced by smoking. Black currant consumption preceding smoking induced a significant decrease in sIgA concentrations 5 min after the intervention compared with the baseline (P=.046), with a further increasing trend, statistically significant, 60 min after the intervention (P=.025). Although smoking cessation is the most important strategy in the prevention of chronic diseases, the obtained results suggest that the influence of black currant consumption on negative effects of tobacco smoke on salivary flow and immunological status of saliva could partly reduce the smoking-associated risk on oral health.

The Biofilm Community-Rebels with a Cause

Oral Biofilms are one of the most complex and diverse ecosystem developed by successive colonization of more than 600 bacterial taxa. Development starts with the attachment of early colonizers such as Actinomyces species and oral streptococci on the acquired pellicle and tooth enamel. These bacteria not only adhere to tooth surface but also interact with each other and lay foundation for attachment of bridging colonizer such as Fusobacterium nucleatum followed by late colonizers including the red complex species: Porphyromonas gingivalis, Tannerella forsythia and Treponema denticola-the founders of periodontal disease. As the biofilm progresses from supragingival sites to subgingival sites, the environment changes from aerobic to anaerobic thus favoring the growth of mainly Gram-negative obligate anaerobes while restricting the growth of the early Gram-positive facultative aerobes. Microbes present at supragingival level are mainly related to gingivitis and root-caries whereas subgingival species advance the destruction of teeth supporting tissues and thus causing periodontitis. This review summarizes our present understanding and recent developments on the characteristic features of supra- and subgingival biofilms, interaction between different genera and species of bacteria constituting these biofilms and draws our attention to the role of some of the recently discovered members of the oral community.

Comparison of the Antibacterial Properties of Three Mouthwashes Containing Chlorhexidine Against Oral Microbial Plaques: An in vitro Study

Background:

The mouth provides an environment that allows the colonization and growth of a wide variety of microorganisms, especially bacteria. One of the most effective ways to reduce oral microorganisms is using mouthwashes.

Objectives:

The aim of this study was to investigate the antibacterial effects of chlorhexidine mouthwashes (manufacture by Livar, Behsa, Boht) on common oral microorganisms.

Materials and Methods:

In this in vitro study, isolated colonies of four bacteria, including Streptococcus mutans, S. sanguinis, S. salivarius and Lactobacillus casei, were prepared for an antimicrobial mouth rinse test. The tube dilution method was used for determining the minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC).

Results:

The MICs for Kin gingival, Behsa and Boht mouthwashes were 0.14, 0.48 and 1000 micrograms/mL using the tube method for S. mutans, respectively. The MBCs for the mentioned mouthwashes were 0.23, 1.9 and 2000 micrograms/mL for S. mutans, respectively. The MICs for Kin gingival, Behsa and Boht mouthwashes were 0.073, 0.48 and 250 micrograms/mL using the tube method for S. sanguinis, respectively. The MBCs for the mentioned mouthwashes were 0.14, 1.9 and 1000 micrograms/mL for S. sanguinis, respectively.

Conclusions:

The Kin Gingival chlorhexidine mouthwash has a greater effect than Behsa and Boht mouthwashes on oral microorganisms and is recommended to be used for plaque chemical inhibition.

Comparison of immunological and microbiological characteristics in children and the elderly with or without dental caries

The purpose of this study was to determine the relationships among early childhood caries (ECC), root caries (RC), the quantity of Streptococcus mutans in saliva, and the concentrations of total and specific secretory IgA (sIgA). Saliva samples were collected from 70 children, 3-4 yr of age, with and without ECC, and from 43 adults, ≥60 yr of age, with and without RC. The decayed, missing, and filled teeth (dmft) and decayed, missing, and filled surfaces (dmfs) scores of each child, and the root decayed and filled teeth (RDFT) and root decayed and filled surfaces (RDFS) scores of each elderly subject, were determined. The S. mutans levels, total sIgA, and specific sIgA against two virulence antigens of S. mutans in saliva were analysed using quantitative real-time PCR (qPCR) and ELISAs. The quantity of S. mutans was significantly higher in caries-positive subjects within the two populations than in the caries-free subjects; and a positive correlation was found between the quantity of S. mutans and the dmft, dmfs, RDFT, and RDFS scores. In addition, the salivary total sIgA was significantly higher in children with severe early childhood caries (SECC) and in the elderly subjects with RC. Moreover, although the S. mutans level was significantly higher, the concentrations of specific sIgA against S. mutans antigens were significantly lower in samples from elderly subjects than in samples from children. These results support the concept that S. mutans is positively associated with ECC and RC. Furthermore, the levels of S. mutans-specific antibodies in saliva are too low to prevent infection with cariogenic bacteria and to inhibit development of ECC and RC.

Dentine bond strength and antimicrobial activity evaluation of adhesive systems

OBJECTIVES

This study evaluated the dentine bond strength (BS) and the antibacterial activity (AA) of six adhesives against strict anaerobic and facultative bacteria.

METHODS

Three adhesives containing antibacterial components (Gluma 2Bond (glutaraldehyde)/G2B, Clearfil SE Protect (MDPB)/CSP and Peak Universal Bond (PUB)/chlorhexidine) and the same adhesive versions without antibacterial agents (Gluma Comfort Bond/GCB, Clearfil SE Bond/CSB and Peak LC Bond/PLB) were tested. The AA of adhesives and control groups was evaluated by direct contact method against four strict anaerobic and four facultative bacteria. After incubation, according to the appropriate periods of time for each microorganism, the time to kill microorganisms was measured. For BS, the adhesives were applied according to manufacturers' recommendations and teeth restored with composite. Teeth (n=10) were sectioned to obtain bonded beams specimens, which were tested after artificial saliva storage for one week and one year. BS data were analyzed using two-way ANOVA and Tukey test.

RESULTS

Saliva storage for one year reduces the BS only for GCB. In general G2B and GCB required at least 24h for killing microorganisms. PUB and PLB killed only strict anaerobic microorganisms after 24h. For CSP the average time to eliminate the Streptococcus mutans and strict anaerobic oral pathogens was 30 min. CSB showed no AA against facultative bacteria, but had AA against some strict anaerobic microorganisms.

CONCLUSIONS

Storage time had no effect on the BS for most of the adhesives. The time required to kill bacteria depended on the type of adhesive and never was less than 10 min.

CLINICAL SIGNIFICANCE

Most of the adhesives showed stable bond strength after one year and the Clearfil SE Protect may be a good alternative in restorative procedures performed on dentine, considering its adequate bond strength and better antibacterial activity.

Passive Immunization

Whereas active immunity refers to the process of exposing the individual to an antigen to generate an adaptive immune response, passive immunity refers to the transfer of antibodies from one individual to another. Passive immunity provides immediate but short-lived protection, lasting several weeks up to 3 or 4 months. Passive immunity can occur naturally, when maternal antibodies are transferred to the fetus through the placenta or from breast milk to the gut of the infant. It can also be produced artificially, when antibody preparations derived from sera or secretions of immunized donors or, more recently, different antibody producing platforms are transferred via systemic or mucosal route to nonimmune individuals. Passive immunization has recently become an attractive approach because of the emergence of new and drug-resistant microorganisms, diseases that are unresponsive to drug therapy and individuals with an impaired immune system who are unable to respond to conventional vaccines. This chapter addresses the contributions of natural and artificial acquired passive immunity in understanding the concept of passive immunization. We will mainly focus on administration of antibodies for protection against various infectious agents entering through mucosal surfaces.

Physiological adaptations of key oral bacteria

Oral colonising bacteria are highly adapted to the various environmental niches harboured within the mouth, whether that means while contributing to one of the major oral diseases of caries, pulp infections, or gingival/periodontal disease or as part of a commensal lifestyle. Key to these infections is the ability to adhere to surfaces via a range of specialised adhesins targeted at both salivary and epithelial proteins, their glycans and to form biofilm. They must also resist the various physical stressors they are subjected to, including pH and oxidative stress. Possibly most strikingly, they have developed the ability to harvest both nutrient sources provided by the diet and those derived from the host, such as protein and surface glycans. We have attempted to review recent developments that have revealed much about the molecular mechanisms at work in shaping the physiology of oral bacteria and how we might use this information to design and implement new treatment strategies.

Preclinical screening of phyllanthus amarus ethanolic extract for its analgesic and antimicrobial activity

BACKGROUND

To discover a new agent which possesses dual property of analgesic and antimicrobial activity, thereby reducing the burden of polypharmacy. Phyllanthus amarus was screened for its analgesic and antimicrobial activities.

OBJECTIVES

The objective was to evaluate the analgesic and antimicrobial activity, of P. amarus ethanolic extract (PAEE).

MATERIALS AND METHODS

The ethanolic extract of P. amarus was prepared using Soxhlet apparatus. An in vivo study using Swiss albino mice was done to screen the central and peripheral analgesic activity of P. amarus extract. The extract was administered at a dose of 100 mg/kg body weight orally. The peripheral analgesic activity was assessed using acetic acid induced writhing test. The central analgesic activity was assessed using Eddy's hot plate apparatus. An in vitro study was carried out to study the antimicrobial activity of the above extract using selected species of Streptococcus mutans, and S. salivarius. The antimicrobial activities were determined using the agar well method.

RESULTS

The ethanolic extract of P. amarus showed significant (P < 0.05) peripheral and central analgesic activity. In vitro antimicrobial screening indicated that the ethanolic extract had shown a zone of inhibition against S. mutans and S. salivarius in the agar wells.

CONCLUSION

This study showed that PAEE exhibited significant analgesic and antimicrobial activities.