Persistent lesions in endodontics

Apical periodontitis is mainly caused by both microrganisms and their virulence factors. This process can be associated with the survival of its causative agents due to coronary microleakage after chemical-mechanical preparation and filling. However, persistent apical periodontitis can be solved through endodontic retreatment or apical surgery. In addition, its association with systemic diseases has been reported in different studies. The aim of the current study is to perform a literature review on studies about apical periodontitis, with emphasis on current microbial profile and treatment modalities. Studies have shown significant heterogeneity in microbial profile, as well as likely associations with some diseases. Moreover, they have mainly focused on investigating persistent apical periodontitis based on molecular biology. It was possible concluding that, although Enterococcus faecalis is the species most often associated with failure in endodontic treatments, the incidence of other microrganisms, such as Candida albicans, Streptococcus spp. , Actinobacteria spp. , has been observed at the same, or even at higher, level than that of E. faecalis. Retreatment should always be taken into consideration as the first option to treat morbidities, although surgery can be performed if retreatment is not successful. Este de la supervivencia de los agentes causales debido la microinfiltración coronaria de la preparación químico-mecánica y la obturación. la periodontitis apical solucionada a través del retratamiento endodóntico o la cirugía apical. Este como objetivo realizar una revisión de literatura sobre la periodontitis apical destacando el perfil microbiano actual y modalidades de tratamiento. Las investigaciones que respecta al microbiano, como la periodontitis apical persistente a nivel molecular. del faecalis la especie más falla la presencia de otros tipos de microorganismos, como: Candida spp. , spp. y de la puede ser realizada. from C. albicans. The following pairs were used to establish four double-species models for starvation rehearsal purposes: E. faecalis and C. albicans (EC), E. faecalis and S. Gordonii (ES), E. faecalis and A. viscosus (EA) and E. faecalis and L. acidophilus (EL). The total bacterial counting was performed at the first, second, fourth, seventh, fourteenth and twenty-eighth starvation day. Bacterial competition during infection was observed under abundant nutrient condition, based on confocal laser scanning microscopy. Results have shown that E. faecalis was more resistant to starvation in coexistence with C. albicans, S. gordonii, A. viscosus, or L. acidophilus; S. gordonii was fully inhibited in coexistence with E. faecalis. The double-species biofilm has shown that E. faecalis coexisting with S. gordonii and A. viscosus has formed biofilms thicker and denser than those formed when it coexisted with C. albicans and L. acidophilus. The aforementioned authors concluded that E. faecalis was more resistant to starvation in coexistence with four other bacteria; A. viscosus and S. gordonii promoted E. faecalis survival due to abundant nutrition. samples were stained through the Live/Dead technique and assessed in confocal laser scanning microscope (CLSM). Bioimage L software was used to measure total bio-volume in um3; viable bacteria rate (green cells) in the biofilm and tooth tubules were found after irrigation. The AgNp solution ruled out fewer bacteria, but it got to dissolve more biofilm than chlorhexidine. NaOCl recorded the highest anti-microbial activity and the highest biofilm dissolution ability. The AgNp solution presented less anti-microbial action in infected tooth tubules than NaOCI. The AgNp solution was the most effective to rule out planktonic bacteria from tooth tubules after 5 minutes than from the biofilm; however, at 30 minutes, less viable bacteria were observed in the biofilm in comparison to the intra-tubular dentin. The aforementioned authors have concluded that irrigant AgNp was not effective against E. faecalis in comparison to solutions oftentimes used to treat root canal. NaOCI is an appropriate irrigant, because it was effective to interrupt the biofilm and to rule out bacteria from the biofilm and from tooth tubules. issue infection control during endodontic treatment/retreatment in-vitro Root using 2.5% 102-105 times, bacterial from 95% 99%. best antimicrobial effects of NaOCl were observed changed on a regular basis and used at large volumes. Chlorhexidine (CHX) was also used as alternative to NaOCl for irrigation purposes; presented antimicrobial results similar to those of out a literature review to identify the microbiota associated with endodonetic failure, as well as the reasons why these microorganisms are capable of surviving basic disinfection procedures. A systematic search for scientific articles was performed in PubMed database, based on the following meshes: "Endodontic Infections", "Endodontic Microbiology", "Endodontic Failure", "Enterococcus Faecalis", "Endodontics Retreatment". Case reports and articles published before 2000 were not included in the review. Most authors highlight E. faecalis as the main microorganism associated with endodontic failure, although there are recent studies that mostly isolated other bacteria, such as Fusobacterium nucleatum and Propioni bacterium. They have concluded that these microorganisms have the following properties – which can form biofilm, and place themselves in areas that are inaccessible to root canal instrumentation techniques - in common: alternative metabolic pathways. discs and a tooth tubule model, respectively. The experiments were conducted based on a two-phase irrigation protocol. Phase 1: modified saline solution (RISA) and sodium hypochlorite (NaOCl) were used at low flow to assess irrigants’ chemical action. Ult rasonic activation (US) of a chemically inert solution (buffer) was used to assess irrigation’s mechanical effectiveness. Phase 2: final irrigation with high flow bu ffer was carried out in all groups. Optical coherence tomography (OCT), low load compression test (LLCT) and scanning laser confocal microscopy analysis were used in different models. The following results were recorded: US and high flow rate have significantly removed more biofilm from the artificial side canal; there were no significant differences between groups. The intra-group analysis showed significant differences among experimental stages, except for NaOCl. With respect to dentine discs, there were no differences in biofilm removal and viscoelasticity. NaOCl presented the highest anti-biofilm efficacy. These authors concluded that irrigation’s mechanic effect is relevant for biofilm removal. Extra high -flow irrigation rate to US be when surface the could after RISA and NaOCI to have changed the remaining post-treatment biofilms.