Reasons for persistent and emerging post‐treatment endodontic disease

Abstract

This article is a critical review of the reasons for persistent and emerging post‐treatment endodontic disease (PTED). While there is a strong consensus that micro‐organisms, mainly bacteria, are practically the only cause of primary apical periodontitis, the reasons for persistent apical periodontitis lesions have been more a matter of debate. The authors of this review focus on the role of micro‐organisms in PTED, and while secondary developments such as cholesterol crystals or foreign material in the periapical area of a tooth with apical periodontitis may contribute to additional irritation and/or an inflammatory reaction, a detailed analysis of the available data suggests that evidence supporting a primary role for such secondary factors without the continued presence of bacteria is lacking. Therefore, even in PTED, elimination of micro‐organisms residing within the tooth structure, root surface, or periapical tissues remains the goal of treatment and the key to long‐term success.

Radiographic Healing after a Root Canal Treatment Performed in Single-rooted Teeth with and without Ultrasonic Activation of the Irrigant: A Randomized Controlled Trial

“…This can be related to a variety of reasons, including the statistical power of the study, the clinical relevance of the in vitro models, the fact that improved cleaning does not automatically result in a better outcome, and the typical irrigation protocols used in this study. Furthermore, other complicating factors such as the details of the root canal anatomy (apical delta and dentinal tubules), the structure of the biofilm, the external biofilm around the root apex, root filling, or the effect of instrumentation could have been more influential than the irrigation procedures used (1).…”

“…The microorganisms are found close to or in the root canal system or at the outside around the root apex (1). The goal of a root canal treatment is to prevent or to heal apical periodontitis; therefore, the microorganisms in both planktonic and biofilm state should be removed from the root canal system (1).…”

Disinfection of the Root Canal System by Sonic, Ultrasonic, and Laser Activated Irrigation

“…1 It was shown recently that the Damköhler number in the apical area during syringe irrigation with a side-vented needle was higher than 1, suggesting that the fluid transport was too slow to ensure adequate refreshment of irrigants (126). This process can be characterized with the (second) Damköhler number, which is defined as the ratio of the typical irrigant transport time to the reaction time.…”

“…Apical periodontitis (AP) is defined as an oral inflammatory disease caused by a reaction of the host immune system to the presence of microorganisms (planktonic state or biofilm) or their products that are close to or in the root canal system or at the outside around the root apex (1). The goal of a root canal treatment is to prevent or heal AP; therefore, the microorganisms in both planktonic and biofilm state should be removed from the root canal system.…”

“…The goal of a root canal treatment is to prevent or heal AP; therefore, the microorganisms in both planktonic and biofilm state should be removed from the root canal system. Furthermore, the tooth and root structure consist of dentin, a porous material containing tubules with a typical diameter of 0.6-3.2 μm and length of 1-2 mm and are accessible for microorganisms (1). Furthermore, the tooth and root structure consist of dentin, a porous material containing tubules with a typical diameter of 0.6-3.2 μm and length of 1-2 mm and are accessible for microorganisms (1).…”