Bacterial pathogenesis and mediators in apical periodontitis

Abstract

Apical periodontitis is a group of inflammatory diseases caused by microorganisms (mainly bacteria) infecting the necrotic root canal system. The pathogenesis of different types of apical periodontitis and even the same type in different individuals is unlikely to follow a stereotyped fashion with regard to the involved bacterial mediators. Disease pathogenesis is rather complex and involves a multitude of bacteria-and host-related factors. This review article discusses the bacterial pathogenesis of acute and chronic apical periodontitis, with the main focus on the bacterial mediators conceivably involved in the different stages of the infectious process, including secreted products (enzymes, exotoxins, N-formyl-methionyl-leucyl-phenylalanine peptides, heat-shock proteins and metabolic end-products) and structural components (lipopolysaccharide, peptidoglycan, lipoteichoic acid, lipoproteins, fimbriae, flagella, outer membrane proteins and vesicles, DNA, and exopolysaccharides). Knowledge of the bacterial factors involved in the pathogenesis of apical periodontitis is important to the understanding of the disease process and to help establishing proper therapeutic measures to inactivate this bacterial "artillery".

Predictive modeling of gingivitis severity and susceptibility via oral microbiota

“…The developmental program between the healthier and the more diseased states was primarily driven by 15 bacterial genera, most of which increased in relative abundance (except two which decreased) along the development. The taxonomic shift of microbiota was accompanied by a functional shift: the observed gingivitis-enriched functions such as flagellar biosynthesis might be traced to bacterial oral mobility, as the flagellar can assist invading host tissues and escaping phagocytosis (Siqueira and Rocas, 2007). For example, Treponema, Selenomonas and Campylobacter, which were among the gingivitis biomarkers in our MiG model, were among the major donors of flagellar biosynthesis pathways in the plaque microbiota of periodontal disease (Wang et al, 2013); in fact, many species in these genera are equipped with flagella (Ruby et al, 1997;Ihara et al, 2003;Liu et al, 2010;Haya et al, 2011).…”

Cervical Necrotizing Fasciitis of Odontogenic Origin in a Diabetic Patient Complicated by Substance Abuse

“…Given the nonspecific nature of primary odontogenic infections, different combinations of virulence factors will cause different diseases in subjects. Knowledge of the main factors involved in the pathogenesis of apical periodontitis may help establish proper therapeutic measures to inactivate this bacterial attack (13).…”

Biofilme E a Patogênese Das Lesões Perirradiculares

“…2 A patogênese da doença é bastante complexa e envolve uma multiplicidade de fatores relacionados às bactérias e ao hospedeiro. 33 Com a infecção pulpar, o egresso de bactérias e seus produtos aos tecidos perirradiculares induzem alterações inflamatórias e imunológicas no periápice na tentativa de conter a disseminação da infecção, estabelecendo-se com isso, um equilíbrio entre defesa e agressão. 4 As lesões perirradiculares podem ser agudas e crôni-cas.…”

“…As crônicas estão usualmente associadas com baixa virulência da comunidade bacteriana envolvida, mas representam uma fonte de agressão persistente aos tecidos, já que da forma como estão organizadas em biofilme e devido à inacessibilidade para as defesas do hospedeiro por causa da localização anatômica da infecção, surgem respostas inflamatórias destrutivas. 14,18,22,23,[33][34][35][36][37][38] As bactérias exercem sua patogenicidade através de mecanismos diretos e/ou indiretos (Quadro 2). Os fatores bacterianos causam os danos diretos às células do hospedeiro e/ou dano à matriz intercelular do tecido conjuntivo.…”

“…Esses fatores envolvem os produtos secretados, incluindo enzimas, exotoxinas e produtos finais metabólicos. 33 Porém, as bactérias ainda podem causar severa destruição aos tecidos …”