Root Canal Cleaning after Different Irrigation Techniques: An Ex Vivo Analysis.

Background and Objectives: The endodontic space is a complex area on both micro and macro levels; therefore, traditional irrigation techniques may not guarantee a complete cleaning of such a complicated tridimensional system. The presented ex vivo study aimed to evaluate root canal cleanliness, obtained through an equal volume of traditionally applied sodium hypochlorite (NaOCl), compared to ultrasonically activated NaOCl and ultrasonically activated NaOCl that had undergone intracanal heating NaOCl. Materials and Methods: A total of 60 freshly extracted human mandibular premolars underwent root sample length standardization (18 mm), root canal preparation and, based on the irrigation method employed, were randomly and equally assigned to three study groups, composed of root samples treated with ultrasonically activated NaOCl, ultrasonically activated NaOCl that had undergone intracanal heating and traditionally applied NaOCl. The root specimens were subsequently fixated with 4% buffered formalin solution and decalcified in Morse liquid. A total often 6-micron-thick serial cross-sections were obtained, dyed using hematoxylin and eosin and examined through an optical microscope at 40×, 100×, and 200×. Results: Ultrasonically activated NaOCl that had undergone intracanal heating showed a significantly smaller amount of debris compared to ultrasonically activated and traditionally applied NaOCl groups (p value < 0.05). Conclusions: Root canal cleanliness saw significant enhancements by ultrasonically activated NaOCl that had undergone intracanal heating.

The incidence of dental fractures in the Italian population during the COVID-19 pandemic: An observational study.

Background: The COVID-19 infection has become a pandemic after breaking out in China in the past months of 2019 and spreading rapidly worldwide. To counter this pandemic, several governments worldwide have taken several drastic measures to try to stop the spread of the virus, including a very strict lockdown that has caused a sudden and, in many cases, negative change in people's daily lives. In the literature, several studies have shown how the pandemic has significantly impaired many people's mental health, causing short- and long-term stress, anxiety, and sleep disturbances. Introduction: This study aims to analyze the correlation between the stress caused by the COVID-19 pandemic and the parafunctions of the temporomandibular joint and masticatory muscles, which in turn, have led to an increase in the incidence of fractures and dental injuries. The ultimate goal is to understand the best choice the dentist must make in the preventive and therapeutic fields. Materials and Methods: A questionnaire called "Incidence of tooth fractures during the COVID-19 pandemic" was prepared using the Google® Forms platform. This questionnaire consists of 13 questions. This electronic questionnaire was addressed to all dentists in the Campania Region (ITA) and disseminated through social networks such as WhatsApp® or Facebook® or E-mail. Results: A total of 730 dentists completed the survey. Of these, 450 (61.7%) stated that the number of patients reporting muscle and joint pain in the morning had increased during the COVID-19 pandemic. 414 (56.7%) dentists noted an increase in parafunction and 392 (53.6%) an increase in dental fractures during the pandemic period. Discussion and Conclusions: As can be seen from the study results, an important correlation was found between the stress resulting from the COVID-19 pandemic and dental fractures. The dental elements treated endodontically, depending on the extent of the damage, require restoration, which is also the best preventive strategy in the case of dental fractures.

Cyclic Fatigue of Different Ni-Ti Endodontic Rotary File Alloys: A Comprehensive Review.

INTRODUCTION: Modern endodontics aims to decrease the bacterial load from the complex endodontic space. Over the years, improvements in the operative phases have led to a considerable increase in the success rate of endodontic treatments. The shaping phase has seen the development of new techniques supported by technological innovations that have led to higher treatment predictability. Endodontic instruments have experienced a series of changes that have led to modifications in their design, surface treatments, and heat treatments. The clinical use of rotating nickel-titanium instruments has become widespread and consolidated, a success due primarily to the alloy's mechanical characteristics, which are superior to steel ones, but also to innovations in instrument design. The advent of the Ni-Ti alloy has kept the concepts and requirements of shaping the same but has modified its implementation in endodontics. AIM: The following review followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) protocol. The research question focused on Ni-Ti endodontic instruments whose cyclic fatigue was evaluated by analyzing cyclic fatigue strength and the incidence of fracture. RESULTS: At the end of the research, 10 systematic reviews and 1 randomized controlled trial were included in this comprehensive review. The most frequently analysed alloys were M-wire, conventional Ni-Ti, and CM-wire. In seven articles, instruments made of M-wire alloy were used; in eight articles, instruments made of conventional Ni-Ti; and in seven articles, instruments made of CM-wire alloy. CONCLUSIONS: The technological evolution of Ni-Ti alloys has led to the development of increasingly high-performance endodontic files that are resistant to cyclic fatigue during clinical practice and have greater resistance to sterilisation practices, making treatment easier and more predictable over time. In particular, heat-treated nickel-titanium root canal instruments present greater resistance to cyclic fatigue than untreated ones and those used with reciprocating kinematics concerning continuous rotation.

Dentinal tubule penetration following ultrasonic, sonic, and single-cone technique of a biosealer: An ex vivo study.

Background: The endodontic space is complex, and using a single-cone obturation technique fails to ensure a complete filling. Introduction: This study aimed to investigate the effect of ultrasonic activation, sonic activation, and single-cone technique of a biosealer on its dentinal tubular penetration. Materials and Methods: In the experiment, single-root mandibular premolars were randomly assigned to three groups (n = 20): group A, ultrasonic activation; Group B, sonic activation; and Group C, single-cone technique. Penetration of the fluorescently labeled biosealer was investigated using a confocal laser scanning microscope. Results: The data were statistically analyzed using Kruskal-Wallis and Mann-Whitney tests (P = 0.05). The highest penetration of biosealer was observed in Group A, followed by Group B (P < 0.05). Conclusions: Dentinal tubule penetration of biosealer was significantly improved by ultrasonic and sonic activation techniques.

Pulp regeneration treatment using different bioactive materials in permanent teeth of pediatric subjects.

Background and Objectives: The present systematic review aims to assess the success rate of the pulp regeneration treatment, according to the American Association of Endodontists (AAE) criteria, using different bioactive materials in permanent teeth of pediatric subjects (6-17 years of age). Materials and Methods: The study protocol was registered on PROSPERO and adhered to the Preferred Reporting Items for Systematic Reviews and Meta-analyses statement. The question formulation was accomplished using the PICO model, and an electronic search was carried out on Scopus, MEDLINE/PubMed, Web of Science, and Cochrane databases till April 1, 2023. A total of 30 studies were established to fulfill the inclusion criteria of this systematic review. Results: A total of 273 teeth have been treated with pulp regeneration treatment. By comparing different biomaterials and the success criteria defined by the AAE, the material associated with a higher success rate was found to be the white mineral trioxide aggregate. However, the overall success rate of pulp regeneration treatment was reported for 248 out of 273 teeth (91.20%). Conclusions: Data obtained support the potential that regenerative endodontics aids in continuing root development in permanent immature teeth. Further studies are needed for a more extensive evaluation of the use of different biomaterials and the success rate in regenerative endodontics.

Traditional and Recent Root Canal Irrigation Methods and Their Effectiveness: A Review.

According to contemporary dental standards, the primary goal of endodontic therapy is the chemo-mechanical cleaning of the complex root canal system. Watering root canals with approved solutions and activating them are essential parts of this operation. This review outlines various irrigant activation methods for root canal therapy. Specifically, a comparison among the methods of manual dynamic activation, sonics (subsonic, sonic, and ultrasonic), internal heating, and lasers, was conducted. The results in this work were gathered using Scopus, Web of Science, Google Scholar, and PubMed databases by searching the following keywords: sodium hypochlorite, cleaning, activation, and irrigation methods. The present work concluded that the use of irrigant activation has a greater benefit than its absence. Regardless, it is impossible to point to a single effective activation method.

Smear Layer and Debris Removal from Root Canals Comparing Traditional Syringe Irrigation and 3D Cleaning: An Ex Vivo Study.

Background: Endodontic treatment objectives comprise eliminating or decreasing bacterial load inside the complex endodontic space. Removing the smear layer and debris becomes mandatory to achieve good three-dimensional (3D) cleaning. Aim: This study assesses the difference in smear layer removal using the 3D cleaning technique and traditional syringe needle irrigation. The 3D cleaning technique includes the ultrasonic activation of intracanal-heated NaOCl. Materials and Methods: Our current study used single-rooted human mandibular premolar teeth to test the earlier-mentioned technique (n = 30). Initially, an endodontic access cavity was performed. Consequently, specimens were randomly distributed into three study groups according to irrigation protocol. The groups were Group 1, where the traditional syringe needle irrigation system was applied; Group 2, where the 3D cleaning technique was performed; and Group 3, in which teeth remained uncleaned as it was regarded as the control group. Once the experiment was completed, the teeth were decoronated at the cementoenamel junction (CEJ) and examined using scanning electron microscopy (SEM). Debris and smear layers were viewed in 1000× magnification and scored. Results: Statistical analysis was performed with a standard statistical software package (SPSS, version 28.0; SPSS IBM, Armonk, NY, USA). Data were analyzed with a nonparametric analysis of variance (Kruskal−Wallis ANOVA) among the groups tested and among the thirds of the canals. The level of significance was set at p < 0.05. A statistically significant (p < 0.05) lower mean smear layer and debris score was observed in both study groups compared to the control group. Group 2 showed better results compared to Group 1. Conclusions: The present study concluded that the 3D cleaning technique is an effective irrigation method for removing debris and smear layers. Future research, such as CLSM (Confocal Laser Scanning Microscopy) and Histological study, should be employed to confirm this study's conclusion.

Histological Evaluation of Root Canals by Performing a New Cleaning Protocol "RUA" in Endodontic Surgery.

AIM: To enhance cleaning during retro-preparation in endodontic microsurgery. MATERIALS AND METHODS: Forty mandibular premolars were instrumented, filled with a single cone technique, and then retro-preparation was performed and assigned to experiment A. In group A1, the cavity created by the retro preparation was cleansed with 2 mL of normal sterile saline. In group A2, the retro cavity was cleaned with 2 mL of sterile saline after the retro preparation. All the irrigation solutions mentioned above were delivered using an endodontic needle with a lateral vent and a gauge of 30. Subsequently, in group A2, 17% EDTA gel and 5.25% gel were inserted into the cavity and activated using ultrasonic tips. After the irrigation protocols, the specimens were decalcified for histological evaluation. RESULTS: In the experiment, the amount of hard tissue debris was significantly greater in group A1 compared to group A2 (p < 0.05). CONCLUSIONS: The samples in group A2, where the new protocol was performed, showed statistically significant results.

Stronger than Ever: Multifilament Fiberglass Posts Boost Maxillary Premolar Fracture Resistance.

This paper investigates the influence of cavity configuration and post-endodontic restoration on the fracture resistance, failure mode and stress distribution of premolars by using a method of fracture failure test and finite elements analysis (FEA) coupled to Weibull analysis (WA). One hundred premolars were divided into one control group (Gcontr) (n = 10) and three experimental groups, according to the post-endodontic restoration (n = 30), G1, restored using composite, G2, restored using single fiber post and G3, restored using multifilament fiberglass posts (m-FGP) without post-space preparation. Each experimental group was divided into three subgroups according to the type of coronal cavity configuration (n = 10): G1O, G2O, and G3O with occlusal (O) cavity configuration; G1MO, G2MO, and G3MO with mesio-occlusal (MO); and G1MOD, G2MOD, and G3MOD with mesio-occluso-distal (MOD). After thermomechanical aging, all the specimens were tested under compression load, and failure mode was determined. FEA and WA supplemented destructive tests. Data were statistically analyzed. Irrespective of residual tooth substance, G1 and G2 exhibited lower fracture resistance than Gcontr (p < 0.05), whereas G3 showed no difference compared to Gcontr (p > 0.05). Regarding the type of restoration, no difference was highlighted between G1O and G2O, G1MO and G2MO, or G1MOD and G2MOD (p > 0.05), whereas G3O, G3MO, and G3MOD exhibit higher fracture resistance (p < 0.05) than G1O and G2O, G1MO and G2MO, and G1MOD and G2MOD, respectively. Regarding cavity configuration: in G1 and G2, G1O and G2O exhibited higher fracture resistance than G1MOD and G2MOD, respectively (p < 0.05). In G3, there was no difference among G3O, G3MO and G3MOD (p > 0.05). No difference was found among the different groups and subgroups regarding the failure mode. After aging, premolars restored with multifilament fiberglass posts demonstrated fracture resistance values comparable to those of an intact tooth, irrespective of the different type of cavity configuration.

Special Issue "The State of the Art in Endodontics" Part II.

The long-lasting success of root canal treatment can be achieved by applying the many advancements and technologies developed during the treatment [...].

Special Issue "The State of the Art in Endodontics".

Currently, the term "modern endodontics" is used more often due to contemporary applied science and original materials that have been developed in recent years [...].

Confocal laser scanning microscopy evaluation of roots subjected to activation protocol in endodontic microsurgery.

This study evaluated the penetration of the irrigant subject to activation after performing retro-preparation in endodontic microsurgery. Forty mandibular premolars were prepared and filled. Subsequently, 1 mm from the root apex was cut using a multi-blade bur and the retro-preparation was performed. In group 1, the retro-cavity was cleaned with 2 mL of saline and then with 2 mL of 5.25% NaOCl gel mixed with 0.1% Rhodamine B. In group 2, the retro-cavity was cleaned with 2 mL of saline, 17% EDTA gel was activated ultrasonically for 30 s and 5.25% NaOCl gel was mixed with 0.1% Rhodamine B and activated for 30 s. After 7 days, the roots were cut at 1mm from the apex and the slices were evaluated with confocal laser scanning microscopy. The samples of group 2 showed statistically better results. The activation protocol proposed resulted in enhanced irrigant penetration when compared to the traditional.

Two-Year Healing Success Rates after Endodontic Treatment Using 3D Cleaning Technique: A Prospective Multicenter Clinical Study.

BACKGROUND: Various irrigation techniques for cleansing the endodontic space have been proposed, and internal heating combined with ultrasonic activation (3D cleaning technique) is considered an effective technique. This prospective multicenter clinical study aims to evaluate healing rates for teeth after root canal treatment utilizing the 3D cleaning technique and to report predictive values for success. MATERIAL AND METHODS: Ninety patients referred for a root canal treatment were included. All enrolled patients were treated with the 3D cleaning protocol. Four endodontists performed the clinical procedures and follow-up evaluations. Preoperative, postoperative and follow-up data were gathered from the consented patients. Each patient was assessed for any clinical signs or symptoms. Afterwards, two trained, blinded, and independent evaluators scored the subject's periapical radiographs. This score was made by checking for the presence or absence of apical periodontitis using the periapical index (PAI). Then, the teeth were classified as healing or healed and were considered a success based on a cumulative success rate of healing. Statistical analysis was performed using the Fisher's exact test, Pearson correlation, and logistic regression analyses of the preoperative prognostic factors at a 0.05 significance level. RESULTS: 90 patients were evaluated at two years with a follow-up rate of 97.7%. The cumulative success rate of healing was 95.4%. Eight predicting aspects were identified by employing bivariate analyses. Then, using logistic analyses, the two prognostic significant variables directly correlated to healing were the preoperative presence of periapical index (p value = 0.016). CONCLUSIONS: In this two-year clinical study, the cumulative success rate of healing was 95.4% when patients were treated with the 3D cleaning protocol.

A novel modified obturation technique using biosealers: An ex vivo study.

Background: The root canal anatomy is a complex space, and using a single-cone obturation technique does not guarantee a complete filling. Aim: This research aimed to evaluate the actual temperature of the biosealer during the obturation phase inside the root canal using a new hot technique. In addition, this study evaluated the penetration depth of the biosealer inside dentinal tubules. Setting and Design: The current study was concluded on two ex vivo experiments; the former tested the temperature evaluation. The latter examined the penetration depth of the biosealer. Materials and Methods: In this study, 42 sec mandibular premolars were used, and two experiments were carried out. In the first experiment, two premolars were utilized, and two thermocouples of K-type for each tooth were used. During the second experiment, the penetration depth of the biosealer was examined, 40 teeth were selected. Root canals were prepared then divided into two obturation groups: A, gutta-percha, and biosealer with single-cone technique and B, gutta-percha, and biosealer with a newly proposed obturation method. Confocal laser scanning was used to assess the penetration of the sealer. Statistical Analysis Used: In the first experiment, the Bonferroni method was performed to compare the temperature data. The tests used in the second experiment were Shapiro-Wilk's test, Kruskal-Wallis, and Mann-Whitney tests. Results: The first experiment results showed that the heat does not reach the apical third using the new obturation method. In the second experiment, the results showed in Group B significantly higher biosealer penetration into the dentinal tubules as compared to Group A (P < 0.05). Conclusions: The highest level of penetration of the biosealer in the dentinal tubules was observed in the group of the new obturation method, and the last apical 3 mm remained at 37° using this novel hot modified technique providing no risk of chemical alteration of the biosealer.

Modern rotary files in minimally invasive endodontics: a case report.

Modern Endodontics aims to remove or decrease the bacterial load within the endodontic space. This target is achieved by performing adequate mechanical preparation combined with three-dimensional cleaning. The first step, shaping, is done using manual stainless steel files and Ni-Ti rotating files. In recent years, new rotating files have been developed in the martensitic phase, which, being more flexible, guarantees to work safely in the case of difficult anatomies. Therefore, this study aimed to demonstrate a non-surgical endodontic treatment using modern Ni-Ti files in a minimally invasive approach.

An innovative technique to safely perform active cleaning in teeth with open apices: CAB technique.

The current study aims to evaluate in vitro the extrusion of NaOCl, using an artificial root canal with an open apex, using different canal irrigation protocols. For this study, a transparent artificial root canal was used. The apex was shaped to be oversized and irregular in form. After root canal mechanical shaping, the artificial cylindrical chamber, which was made below the large apical foramen, was filled with fuchsine-stained bovine pulp tissue. Afterward, irrigation protocols were carried out and compared regarding their safety with regards to irrigant extrusion. Subsequently, the examiner created two groups, Group A: internal heating associated with ultrasonic activation and Group B: internal heating associated with ultrasonic activation, using the CAB technique. In both the groups, 5.25% sodium hypochlorite solution was used as the irrigant. Regarding assessing the presence or absence of the extrusion, photographs at ×20 were taken and analyzed. For the statistical analysis, a t-test for paired samples was used. Extrusion of irrigant beyond the apex was present only in Group A. The main objective of endodontic treatment is the removal of damaged tissues and bacteria. For this reason, active cleaning is crucial in all endodontic treatment cases. Internal heating followed with ultrasonic activation while using the CAB technique was an effective and safe technique to ensure no irrigant extrusion beyond the open apex.

Effect of different final irrigation protocols on pulp tissue dissolution from an isthmus model.

This study assessed the pulp tissue dissolution from isthmus of a two-rooted maxillary premolar using different final irrigation protocols. After root canal preparation, the surface of the tooth was reduced to an extent that the isthmus could be observed, and 1 mg of pulp tissue was introduced into the isthmus which was covered with a glass slide. Following six groups were tested: syringe and needle; subsonic activation; sonic activation; ultrasonic activation; heating followed by sonic activation; and heating followed by ultrasonic activation. Before and after each experiment a photograph of the isthmus was taken at 30× to register the area of the pulp tissue. Statistical analysis was performed with Kruskal-Wallis and Mann-Whitney tests (P < 0.05). Syringe and needle group showed the lower value of pulp tissue dissolution followed by subsonic irrigation procedures. Pulp tissue dissolution was significantly higher when heating was followed by sonic or ultrasonic activation.

Conservative shaping combined with three-dimensional cleaning can be a powerful tool: Case series.

Conservative endodontics has been introduced about a decade ago. Since then, it has been demonstrated that less canal preparations lead to more dentin preservation resulted in decreased stress on tooth structure, mainly in the coronal third of the root, and potentially a higher resistance to fracture. In addition, smaller and larger canal preparations were comparable with regard to the cleanliness of the root canal. The purpose of this case series was to report on the outcome of root canal treatments following a conservative canal preparation, followed by three-dimensional cleaning technique (intracanal heating and ultrasonic activation of NaOCl).

Dentinal tubule penetration and root canal cleanliness following ultrasonic activation of intracanal-heated sodium hypochlorite.

This study investigated the effect of ultrasonic activation of intracanal-heated sodium hypochlorite (NaOCl) on its dentinal tubular penetration and root canal cleanliness in vitro. In experiment 1, mandibular premolars were randomly allocated to three groups (n = 8): group A, ultrasonic activation; group B, ultrasonic activation of intracanal-heated NaOCl and group C, syringe-and-needle irrigation. Penetration of the fluorescent-labelled NaOCl was investigated using light microscopy. In experiment 2, mandibular premolars were randomly allocated to group B or C (n = 10), for histological analysis of the remaining pulp tissue and debris. Data were statistically analysed using Kruskal-Wallis and Mann-Whitney tests (P = 0.05). The highest penetration of NaOCl was observed in group B, followed by group A (P < 0.05). Group B showed significantly less amount of debris than group C (P < 0.05). Dentinal tubule penetration of NaOCl and root canal cleanliness were significantly improved by ultrasonic activation of intracanal-heated NaOCl.

Evaluation of the actual chlorine concentration and the required time for pulp dissolution using different sodium hypochlorite irrigating solutions.

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 endodontic therapy. One of the most commonly used root canal irrigants 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 NaOCl, 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 NaOCl were selected for this study: 5% NaOCl (ACE, Procter and 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 ml × 5 ml tubes were filled. All samples were divided into three groups and were analyzed using the DIN EN ISO 7393-2 method and the percentage of total chlorine (expressed as a percentage) was calculated. Forty 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 (×40), 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 was 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, whereas 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 NaOCl 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 <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 and hence that a lower time corresponds to a higher concentration.