Hany Mohamed Aly Ahmed

Current Assessment of Reciprocation in Endodontic Preparation: A Comprehensive Review--Part II: Properties and Effectiveness.

INTRODUCTION Many reciprocating file systems (RFs) have recently been introduced. This article reviews the properties, effectiveness, and clinical outcomes of the RFs. METHODS A PubMed electronic search was conducted by using appropriate key words to identify investigations on RFs. After retrieving the full-text relevant articles, the cross citations were also identified. RESULTS This review summarizes the mechanical properties, shaping ability, preservation of the root canal anatomy, shaping time, cleaning effectiveness, microcrack formation, bacterial reduction, extrusion of debris, and removal of root canal filling materials of RFs. CONCLUSIONS The favorable results of RFs indicate their potential application as viable alternatives to rotary file systems, yet no filing system is able to entirely prepare the dentin of canals, totally eliminate sessile and planktonic microorganisms, or remove the filling material completely from the root canal system.

Discolouration potential of endodontic procedures and materials: A review

Advances in endodontic materials and techniques are at the forefront of endodontic research. Despite continuous improvements, tooth discolouration, especially in anterior teeth, is considered an undesirable consequence following endodontic treatment as it creates a range of aesthetic problems. This article aims to discuss the intrinsic and internalized tooth discolouration caused by endodontic procedures, and to address the discolouration potential of materials used during root canal treatment, including root canal irrigants, intra-canal medicaments, endodontic and post-endodontic filling materials. In addition, the discolouration patterns caused by combined endodontic and nonendodontic aetiological factors are discussed. The recommended guidelines that should be followed by dental practitioners to prevent and manage tooth discolouration are also outlined.

Anatomical challenges, electronic working length determination and current developments in root canal preparation of primary molar teeth.

Paediatric endodontics is an integral part of dental practice that aims to preserve fully functional primary teeth in the dental arch. Pulpectomy of primary molars presents a unique challenge for dental practitioners. Negotiation and thorough instrumentation of bizarre and tortuous canals encased in roots programmed for physiological resorption are the main challenges for this treatment approach. Consequently, numerous in vitro and in vivo studies have been conducted to validate the application of some contemporary endodontic armamentarium for effective treatment in primary molars whilst maintaining favourable clinical outcomes. Electronic apex locators, rotary nickel-titanium files and irrigation techniques are at the forefront of endodontic armamentarium in paediatric dentistry. Hence, this review aims to map out the root and root canal morphology of primary molars, to discuss the application of electronic apex locators in primary molars and to provide an update on the preparation of their root canal systems.

Current Assessment of Reciprocation in Endodontic Preparation: A Comprehensive Review—Part I: Historic Perspectives and Current Applications

INTRODUCTION During the evolution of mechanical instrumentation in endodontics, an important role has been played by reciprocating stainless steel files using horizontal rotational, vertical translational, or combined movements. These kinds of systems are still in use mainly as an accessory to help in the first phases of the treatment. METHODS The literature concerning these systems has been analyzed using selected criteria. RESULTS The latest evolution of horizontal rotational reciprocating movement brought to the development of a different kind of movement in which the angles are asymmetrical and that appears to be ideal in conjunction with modern nickel-titanium (NiTi) files with a greater taper. Initially, this movement was limited to particular handpieces available on the market that was used with existing NiTi files to complete root canal instrumentation. Later on, specific files and proprietary motors were introduced into the market. The differences between reciprocating motion used for NiTi and stainless steel files are described and critically analyzed. CONCLUSIONS A classification of the different mechanical reciprocating motions used is presented, thus enabling an easier understanding of these systems and anticipated future developments.

A new system for classifying root and root canal morphology.

Knowledge of root and root canal morphology is a prerequisite for effective nonsurgical and surgical endodontic treatments. The external and internal morphological features of roots are variable and complex, and several classifications have been proposed to define the various types of canal configurations that occur commonly. More recently, improvements in nondestructive digital image systems, such as cone-beam and micro-computed tomography, as well as the use of magnification in clinical practice, have increased the number of reports on complex root canal anatomy. Importantly, using these newer techniques, it has become apparent that it is not possible to classify many root canal configurations using the existing systems. The purpose of this article is to introduce a new classification system that can be adapted to categorize root and root canal configurations in an accurate, simple and reliable manner that can be used in research, clinical practice and training.

The antibacterial activity of sodium hypochlorite and chlorhexidine against Enterococcus faecalis: A review on agar diffusion and direct contact methods

Complete debridement and disinfection of the root canal system are fundamental requirements for successful endodontic treatment. Despite the morphological challenges of the internal root anatomy, root canal irrigants play an important role in the optimization of the root canal preparation, which is essentially a chemo-mechanical procedure. Enterococcus faecalis is one of the most resistant microorganisms that dominants the microbial ecosystem of persistent periradicular lesions in retreatment cases. For that reason, many in vitro and in vivo studies evaluated and compared the antibacterial activity of sodium hypochlorite and chlorhexidine at varying concentrations using different experimental models against this microorganism. However, many controversies with regard to the ideal irrigant and concentration do in fact exist. Hence, this review aims to discuss the antibacterial activity of these two main root canal irrigants against Enterococcus faecalis using the agar diffusion and direct contact methods and the possible modulating factors responsible for inconsistent findings among different studies. In addition, the disinfection potential of both chemical agents on gutta percha and Resilon cones are also discussed. The source of this review was conducted through an electronic literature search using PubMed database from December 1997 until December 2011, which analyze the related laboratory investigations of both irrigants, published in major endodontic journals.

Accessory roots in maxillary molar teeth: A review and endodontic considerations

Maxillary molar teeth may have accessory roots. The aim of this paper is to review and discuss the endodontic implications of this anatomical variation. A review of the literature was undertaken to identify studies and reported cases where accessory roots have been recorded in maxillary molar teeth. The results show that although the prevalence of accessory roots in maxillary molar teeth is low, they can exist in all three types of maxillary molar teeth, and they may be located palatally, buccally, mesially or distally. Hence, it is essential that dentists undertaking root canal treatment thoroughly assess all teeth to determine how many roots are present in order to provide the best possible outcome of treatment for the patient.

Sodium Hypochlorite Accident: A Systematic Review

Introduction: Sodium hypochlorite (NaOCl) extrusion beyond the apex, also known as “a hypochlorite accident,” is a well‐known complication that seldom occurs during root canal therapy. These “accidents” have been the subject of several case reports published over the years. Until now, no publication has addressed the global synthesis of the general and clinical data related to NaOCl extrusion. The main purpose of this article was to conduct a systematic review of previously published case reports to identify, synthesize, and present a critical analysis of the available data. A second purpose was to propose a standardized presentation of reporting data concerning NaOCl extrusions to refine and develop guidelines that should be used in further case report series. Methods: A review of clinical cases reporting NaOCl accidents was conducted in June 2016 using the Preferred Reporting Items for Systematic Reviews and Meta‐Analyses checklist; it combined an electronic search of the PubMed database and an extensive manual search. Results: Forty full‐text articles corresponding to 52 case reports published between 1974 and 2015 were selected. Four main categories of data were highlighted: general and clinical information, clinical signs and symptoms of NaOCl extrusions, management of NaOCl extrusions, and healing and prognosis. Overall, up to now, clinical cases were reported in a very unsystematic manner, and some relevant information was missing. Conclusions: A better understanding of the potential causes, management, and prognosis of NaOCl accidents requires a standardization of reported data; this study proposes a template that can fulfill this objective. Highlights:Knowledge on hypochlorite extrusions during endodontic treatment is primarily based on previously published case reports.The management of hypochlorite extrusions appears to be very empirical.The literature showed that clinical cases were reported in an unsystematic manner, and some relevant information was missing.The present study proposes a template that can fulfill standardization objectives and paves the way for better understanding of the factors, management, and prognosis of hypochlorite accidents.

Assessment of Root Canal Filling Removal Effectiveness Using Micro–computed Tomography: A Systematic Review

Introduction The removal of obturation materials from the root canal system is a primary objective in root canal retreatment procedures. This systematic review aims to discuss the effectiveness of different instrumentation procedures in removing root‐canal filling materials assessed by micro‐computed tomography. Methods An electronic search in PubMed and major endodontic journals was conducted using appropriate key words to identify investigations that examined the effectiveness of obturation material removal assessed by micro‐computed tomography. Results Among 345 studies, 22 satisfied the inclusion criteria. Seven studies compared hand instrumentation with Nickel‐Titanium rotary or reciprocating systems. Three studies investigated rotary systems, and another three studies explored reciprocation. Eight studies compared rotary systems and reciprocation in removing filling materials from the root canal system. Other factors, such as the role of solvents and irrigant agitation, were discussed. Conclusions The application of different instrumentation protocols can effectively, but not completely, remove the filling materials from the root canal system. Only hand instrumentation was not associated with iatrogenic errors. Reciprocating and rotary systems exhibited similar abilities in removing root filling material. Retreatment files performed similarly to conventional ones. Solvents enhanced penetration of files but hindered cleaning of the root canal. The role of irrigant agitation was determined as controversial. HighlightsOrthograde retreatment requires the removal of previous root canal filling materials.Twenty‐two studies were included in the systematic review.None of the protocols investigated was able to fully remove root canal filling materials.Reciprocating and rotary methods have a similar ability in removing root filling material.Only hand instrumentation was not associated with iatrogenic errors.Hybrid protocols are likely to improve cleanliness.

Cell attachment properties of Portland cement-based endodontic materials: biological and methodological considerations.

INTRODUCTION The attachment and spreading of mammalian cells on endodontic biomaterials are an area of active research. The purpose of this review is to discuss the cell attachment properties of Portland cement (PC)-based materials by using scanning electron microscope (SEM). In addition, methodological aspects and technical challenges are discussed. METHODS A PubMed electronic search was conducted by using appropriate key words to identify the available investigations on the cell attachment properties of PC-based endodontic materials. After retrieving the full text of related articles, the cross citations were also identified. RESULTS A total of 23 articles published between January 1993 and October 2013 were identified. This review summarizes the cell attachment properties of commercial and experimental PC-based materials on different cell cultures by using SEM. Methodological procedures, technical challenges, and relevance of SEM in determining the biological profile of PC-based materials are discussed. CONCLUSIONS SEM observations demonstrate that commercial MTA formulations show favorable cell attachment properties, which is consistent with their successful clinical outcomes. The favorable cell attachment properties of PC and its modified formulations support its potential use as a substitute for mineral trioxide aggregate. However, researchers should carefully select cell types for their SEM investigations that would be in contact with the proposed PC-based combinations in the clinical situation. Despite being a technical challenge, SEM provides useful information on the cell attachment properties of PC-based materials; however, other assays for cell proliferation and viability are essential to come up with an accurate in vitro biological profile of any given PC-based formulation.