Dental pulp tissue engineering (TE) quests to regenerate dentin/pulp complex by combining a suitable supporting matrix, stem cells, and biochemical stimuli. Such procedures foresee a matrix that can be easily introduced into the root canal system (RCS) and tightly adhere to dentin walls to assure the dentin surface's proper colonization with progenitor cells capable of restoring the dentin/pulp complex. Herein was investigated an injectable self-setting hyaluronic acid-based (HA) hydrogel system, formed by aldehyde-modified (a-HA) with hydrazide-modified (ADH), enriched with platelet lysate (PL), for endodontic regeneration. The hydrogels' working (wT) and setting (sT) times, the adhesion to the dentine walls, the hydrogel's microstructure, and the delivery of human Dental Pulp Cells (DPCs) were studied in vitro. Hydrogels incorporating PL showed a suitable wT and sT and a porous microstructure. The tensile tests showed that the breaking point occurs after 4.13 mm deformation. While in the indentation test after 1.3 mm deformation. Both breaking points occur in the hydrogel extension. The HA/PL hydrogels exhibited supportive properties and promoted cell migration toward dentin surfaces in vitro. Overall, these results support using PL-laden HA injectable hydrogels (HA/PL) as a biomaterial for DPCs encapsulation, thereby displaying great clinical potential towards endodontic regenerative therapies.

Periapical diseases are a frequent evolution of pulp necrosis. They appear without any painful episode. The incidence splits between 6% and 55%. Initially we can treat inflammatory periapical injury by conservative approach and studies reported 85% of success rate after endodontic disin-fection. Several techniques can be described in the nonsurgical management of peri-radicular le-sions: the root canal treatment, decompression procedure, decompression technique, calcium hydroxide, Apexum procedure. Unfortunately, periapical lesion recuperating is an unpredictable procedure. In some cases surgical approach is preffered to manage large periradicular wound including periapical cysts and abscess. periodic examination is primordial to evaluate efficacy of the therapy. In this report we describe an inflammatory radicular cyst of the anterior maxilla with which was successfully treated by conventional root canal retreatment and endodontic surgery

INTRODUCTION The goal of root canal treatment is to shape and clean the endodontic space, reducing the bacterial load and removing the pulp tissue. Obviously, the action of the endodontic instruments is limited to the main canals, regardless of the complexity of the endodontic space. Consequently, finding the best possible cleaning technique, which can be obtained chemically using irrigation solutions, is a fundamental aid in the endodontic therapy. One of the most commonly used root canal irrigant is sodium hypochlorite (NaOCl), available in various commercial formulations. The effectiveness of NaOCl is undeniable. However, the action of dissolution of the pulp tissue is merely dependent on the concentration and the characteristics of the irrigant itself. AIM The aim of this study is to evaluate the effective concentration of different commercial formulas of sodium hypochlorite, by evaluating the percentage of total chlorine in each product. The dissolution capacity of the pulp tissue of each of the tested products was then analyzed by measuring the required time. MATERIALS AND METHODS Three commercial types of sodium hypochlorite were selected for this study: 5% NaOCl (ACE, Procter & Gamble), 5% NaOCl (N5, Simit Dental) and 6% NaOCl (CanalPro, Coltene). For each product, 10 packages were used, from which samples of the product were taken and 30 x 5 ml tubes were filled. All samples were divided into 3 groups and were analyzed using the DIN EN ISO 7393-2 method and the percentage of total chlorine (expressed as a percentage) was calculated. 40 samples of vital pulp were obtained from teeth freshly extracted for periodontal reasons and stored in physiological solution. In order to unify the size and weight of the samples (0.0001 mg), a microtome and a precision balance (Pro Explorer Ohaus) were used. Each sample, carefully examined by stereomicroscope (40x), was placed in artificial plastic containers and submerged in 0.1 ml of irrigating solution at room temperature (26 ° C). A fourth control group used saline solution as irrigant. Simultaneously with the insertion of the irrigating solution, a digital stopwatch was activated and the time necessary for the complete dissolution of the pulp sample was measured. The data obtained were subjected to statistical analysis. RESULTS The average percentages of chlorine detected for each group were: 4.26% (ACE), 5.16% (N5) and 5.97% (CanalPro). The Kruskal-Wallis test showed statistically significant differences between the different commercial formulations of hypochlorite (P <0.05). CanalPro showed the lowest values, while ACE showed the highest values of dissolution time of the pulp. DISCUSSION The analysis of the total chlorine percentage found that the actual concentration of the sodium hypochlorite in the samples is close to the values declared by the manufacturers both in the case of N5 and CanalPro. On the contrary, the concentration detected in the samples of common bench bleach (ACE) is significantly lower, which has average values less than 5%. This explains the longer time taken for the complete dissolution of the pulp tissue. The average dissolution time of the pulp samples was in fact inversely proportional to the concentration detected in the tested irrigants, so that a lower time corresponds to a higher concentration.

(1) Background: Bacterial reinfection and root fracture are the main culprits related to root canal treatment failure. This study aimed to assess the utility of quercetin solution as an adjunctive endodontic irrigant that strengthen root canal dentin with commitment anti-biofilm activity and bio-safety. (2) Methods: Based on a noninvasive dentin infection model, dentin tubules infected with Enterococcus faecalis (E. faecalis) were irrigated with sterile water (control group), and 0, 1, 2, 4 wt% quercetin-containing ethanol solutions. The live and dead bacteria proportions within E. fae-calis biofilms were analyzed using confocal laser scanning microscopy (CLSM). Elastic modulus and hydroxyproline release and X-ray photoelectron spectroscopy (XPS) characterization was tested on irrigant-treated demineralized dentin to evaluate irrigants’ biostability. The cytotoxicity of irrigants was tested by CCK-8 assay. (3) Results: Quercetin increased the proportion of dead bacteria volumes within E. faecalis, and improved the flexural strength of dentin collagen com-pared to control group. The XPS characterization revealed an increase in C-O peak area under both C1s and O1s narrow-scan spectra. The CCK-8 assay confirmed no cytotoxicity of quercetin solutions. (4) Conclusions: Quercetin exhibited anti-biofilm activity, collagen-stabilizing effect as well as cytocompatibility, supporting quercetin as a potential candidate for endodontic irrigant.

Regenerative endodontic procedures (REPs) aim at recreating dental pulp tissue using biomaterials such as hydrogels. Their bioactivity is mostly linked to the nature of biomolecules or chemical compounds that will compose the endodontic hydrogel. However, many other parameters, such as hydrogel concentration, type, bioactive molecules solubility, of apex size were reported to influence the hydrogel behavior, leading to the inability to predict the clinical outcome. This lack of knowledge and the various parameters that should be considered, suggest that biological activity of endodontic hydrogel is impossible to anticipate and could hinder the bench to bedside transition. We formulated in this article our opinion that most of these parameters could be identified, described, and studied. A second part of the document lists some challenges and perspectives, including development of future mathematical models able to explain and predict the bioactivity of these endodontic hydrogel in clinic.

(1) Background: Non-surgical endodontic treatment has been repeatedly shown to be clinically successful, however, clinical data are scarce. This practice-based retrospective clinical study aimed to investigate endodontic outcome over 40 years and to identify relevant factors from clinical protocols. (2) Methods: Two experienced dental practitioners in two different private dental practices treated 174 patients with 243 teeth from 1969 to 1993. After obturation, either a new restoration (amalgam, resin composite, glass-ionomer cement), or re-cementation of pre-existing prosthetic restorations or its renewal followed. Metal posts (operator A) or screws (operator B) were inserted when indicated. The primary outcome (tooth survival) was achieved when the endodontically treated tooth was in situ, painless and in full function. Secondary outcome was to investigate the impact of potential prognostic factors on survival rates. (3) Results: Overall mean 40-years survival was 56.1% of all treated teeth after 40 years of clinical service resulting in an annual failure rate of 1.1%. Most investigated clinical factors (Jaw, tooth position, number of intracanal dressings, post/screw placement, sex) had no significant influence on survival. Among postendodontic restorations, resin composite was advantageous. (4) Conclusions: Even with materials and techniques from the 1970’s and 1980’s, successful root canal treatment was achievable. Except postendodontic restorations, most of the evaluated factors had no significant influence on clinical long-term survival of root-canal treated teeth.