Functional forces might also lead to fracture after endodontic treatment. This might occur secondary to exposure to erosion, abrasion, physical trauma, and caries. Interventing against these events can be achieved by conducting long follow-up periods and enhancing the endodontic treatment approaches. The current endodontic treatment modalities aim at tissue preservation to enhance resistance to fractures and prevent potential post-treatment complications. In this context, evidence shows the validity of minimally invasive modalities in endodontic treatment with favorable outcomes and reduced frequency of complications. In the present literature review, we have discussed the efficacy of minimally invasive biological treatment in endodontics. It is vital to maintain the integrity of the structures of the tooth-related paracervical area, particularly when treating molars. This is attributed to enhancing the long-term survival rates of the pericervical dentin of these teeth. The current trends represent a revolution in the field of endodontic treatment. This is attributed to the novel development of the various disinfection modalities, which do not need to shape the canal into a round form and induce flaring reactions. Overall, the main advantages of vital pulp therapy include being simple, reduced cost, and reduced risk of treatment-related complications secondary to overcoming the difficulties with the anatomy of the root canals.

Bacterial persistence has been reported to play critical roles in endodontic treatment failure, which attribute to deficient root canal filling and inadequate chemomechanical preparation. The persistence of bacteria to the different eradication approaches during endodontic treatment has been an area of interest in the field of dentistry due to the different roles by which these bacteria might impact endodontic treatment and can even lead to treatment failure. The present investigation provides evidence regarding the persistence of bacteria and its role in the failure of endodontic treatment. At first, we provided an overview of the potential role that bacterial infections might play in endodontic treatment and how the outcomes can be potentially impacted. Then, we discussed the virulence factors that help the different organisms to persist against the different eradication approaches, which can finally lead to the development of endodontic treatment failure. Our findings show that E. faecalis is the most prevalent bacteria causing endodontic treatment failure. However, many studies have reported that other bacteria and pathogens might also be prevalent and exceed the rate of E. faecalis. This indicates the importance of detecting appropriate biofilms to adequately eradicate the underlying pathogens and enhance the treatment and prognostic outcomes.

In the current practice, evidence shows that the currently used irrigant solutions (including sodium hypochlorite combined with and without chlorhexidine or ethylenediaminetetraacetic acid) cannot achieve full cleaning outcomes of the root canal. Accordingly, recent approaches were directed to innovate more efficacious modalities that can overcome the limitations of manual instrumentation and irrigation solutions. In this context, ultrasonic irrigation has been described in the literature as a favorable approach with significantly enhanced outcomes. We have provided evidence regarding the use of ultrasonic irrigation in endodontics. Our findings indicate that passive ultrasonic irrigation is more effective than manual instrumentation in eradicating debris and achieving favorable disinfection. Besides, it has been evidenced that the modality significantly reduces the time to achieve favorable treatment outcomes compared with the traditional approaches. It has been furtherly shown that more favorable outcomes were associated with the combined use of passive ultrasonic irrigation with manual instrumentation. Therefore, it has been suggested that manual instrumentation should be used at the initial phase to achieve adequate preparation, and passive ultrasonic irrigation should be used later on to achieve root canal cleaning.

Dental pulp necrosis is referred to the situation in which the teeth biologically die due to bacterial infection or without bacterial infection. Dental pulp necrosis can be due to a chronic progression of pulpitis, in which the tissue of soft pulp in the tooth dies due to several causes such as trauma or severe bacterial infection. Untreated cavities, multiple invasive treatments for the tooth, and pathological ischemia for dental pulp are among the most common causes for the necrosis process. Usually, the first symptom of dental pulp necrosis is the irritant pain in the tooth only or the surrounding area because of the inflammation. The grade of pain ranges from mild, moderate, to severe pain according to the size of the damage, followed by swelling and discomfort in chewing due to the pressure on the nerve root at the base of the tooth. We aim to review the different etiologies, risk factors, correlations, and clinical outcomes associated with pulp necrosis. To our knowledge, this article is going to be the first comprehensive review of dental pulp necrosis.