Related Experiment Video
Updated: Jul 7, 2026
10:26
Inducing Apical Periodontitis in Mice
Published on: August 6, 2019
Bacterial pathogenesis and mediators in apical periodontitis
José F Siqueira1, Isabela N Rôças
1Department of Endodontics, Estácio de Sá University, Rio de Janeiro, RJ, Brazil. jf_siqueira@yahoo.com
Brazilian Dental Journal
|February 19, 2008
Summary
Apical periodontitis involves complex bacterial and host factors. Understanding bacterial mediators in acute and chronic forms is key to developing effective treatments for this root canal infection.
Area of Science:
- Microbiology
- Endodontics
- Immunology
Background:
- Apical periodontitis is an inflammatory condition originating from microbial infection of the necrotic root canal system.
- The pathogenesis is complex, involving interactions between diverse bacterial species and host responses, rather than a single pathway.
Purpose of the Study:
- To review the bacterial pathogenesis of acute and chronic apical periodontitis.
- To focus on the specific bacterial mediators implicated in the various stages of the infectious process.
Main Methods:
- Literature review of scientific articles on apical periodontitis and its bacterial causes.
- Analysis of secreted bacterial products and structural components contributing to disease development.
Main Results:
- Identified numerous bacterial factors, including secreted enzymes, exotoxins, and structural components like lipopolysaccharide and peptidoglycan.
- Highlighted the role of bacterial mediators such as N-formyl-methionyl-leucyl-phenylalanine peptides, heat-shock proteins, and metabolic end-products.
- Detailed the contribution of structural components like lipoproteins, fimbriae, flagella, and outer membrane vesicles.
Conclusions:
- A comprehensive understanding of bacterial factors is crucial for elucidating the pathogenesis of apical periodontitis.
- Knowledge of these bacterial virulence factors can guide the development of targeted therapeutic strategies to combat root canal infections.
Related Concept Videos
01:20Determinants of Bacterial Pathogenicity and Virulence
Pathogenic bacteria employ a variety of strategies to establish infections, including the secretion of extracellular enzymes that act as potent virulence factors. These enzymes facilitate bacterial colonization of host tissues and help evade immune surveillance. By targeting structural components of host tissues and interfering with immune mechanisms, these enzymes play a pivotal role in disease progression.Extracellular Enzymes Facilitating Tissue Invasion: Several bacterial pathogens secrete...
01:27The Oral Microbiota
The oral microbiome includes a complex ecosystem comprising over 700 microbial species, identified through genomic sequencing and culture-based analyses to date. This community includes a core microbiome, found universally among individuals, and a variable component influenced by environmental factors such as diet, lifestyle, and host genetics. Site-specific conditions, including oxygen gradients, pH levels, and nutrient availability, determine the spatial distribution of these microorganisms...
01:26Bacterial Meningitis II: Pathophysiology
Bacterial meningitis typically begins when pathogens such as Neisseria meningitidis and Streptococcus pneumoniae colonize the nasopharynx and invade the bloodstream. This process is facilitated by bacterial virulence factors, such as polysaccharide capsules, which resist phagocytosis and complement-mediated killing. Less commonly, bacteria reach the central nervous system via contiguous spread from infections like otitis media or sinusitis, through congenital or acquired dural defects, or...
01:28Gene Regulation in Microbial Communities: Quorum Sensing
Quorum sensing is a mechanism of bacterial communication that enables coordinated gene expression in response to changes in population density. This facilitates collective behaviors that enhance survival, resource acquisition, and ecological adaptation. This process relies on small signaling molecules called autoinducers that accumulate as bacterial populations grow. When a critical threshold concentration of autoinducers is reached, bacterial cells collectively modify gene expression,...
01:31Defense Against Bacterial Pathogens
The human immune system is a complex network of cells, tissues, and organs that work together to defend the body against bacterial infections. It consists of various immune cells, each playing a specific role in the defense mechanism.
Phagocytes
Phagocytes are the frontline soldiers of the immune system. They include neutrophils and macrophages. Neutrophils are the most abundant type of white blood cell and are quickly mobilized to the site of infection. Macrophages are larger cells that patrol...
Phagocytes
Phagocytes are the frontline soldiers of the immune system. They include neutrophils and macrophages. Neutrophils are the most abundant type of white blood cell and are quickly mobilized to the site of infection. Macrophages are larger cells that patrol...
01:26Acute Inflammation II: Cellular Phase
The cellular phase of acute inflammation is a tightly orchestrated sequence of events that recruits leukocytes, primarily neutrophils, to sites of tissue injury or infection. Following the initial vascular changes, this phase ensures effective immune cell migration, activation, and function at the affected site to eliminate pathogens and initiate tissue repair.Leukocyte Recruitment CascadeLeukocyte recruitment happens in four steps: margination, adhesion, transmigration, and chemotaxis. Reduced...