sousan shalavi

Naturally occurring in citrus fruits, citric acid is categorized as a weak organic acid, which may exist both as a monohydrate or in an anhydrous form. In biochemistry, this organic acid acts as an intermediate in an essential metabolic process in all aerobic organisms called the Krebs cycle. The literature on citric acid in the context of endodontics up to June 2020 was reviewed using PubMed and MEDLINE. This review aimed to address the antibacterial efficacy of citric acid on endodontic microbiota, its effectiveness on the smear layer, the effects of its toxicity on fracture resistance of dentin, as well as the effectiveness of this acid on the removal of intra-canal medicaments. This report also addressed citric acid-containing endodontic irrigants.

This paper aims to review the different characteristics of root canal irrigants including sodium hypochlorite (NaOCl), chlorhexidine (CHX), hydrogen peroxide (H2O2), iodine potassium iodide (IKI), antibiotic-based irrigants, photo-activated disinfection, electrochemically activated water, and QMix. The literature on root canal irrigation solutions in the context of endodontics up to June 2020 was reviewed using PubMed and MEDLINE. NaOCl was identified as the most likely effective irrigation solution that could be used for endodontics. Its antimicrobial activity is at least comparable or even greater than that of other common irrigants. Tetraclean was also proposed to be more effective than CHX against endodontic microorganisms. In addition, Hypoclean was suggested as the most potent and effective irrigant against Candida albicans. Similarly, IKI was introduced as a successful irrigant in killing Candida albicans and Enterococcus faecalis. MTAD is also known to be effective in smear layer removal as well as against the growth of Enterococcus faecalis. EDTA is also considered to have limited antimicrobial activity.

Due to the complex micro-anatomy of the root canal system, mechanical instrumentation leaves significant portions of the root canal walls untouched; therefore, complete elimination of bacteria from the root canal by cleaning with instrumentation alone is unlikely. It has long been postulated but not demonstrated, that any pulp tissue left in the root canals can serve as bacterial/fungal/viral (microorganism nutrients) nutrients. Furthermore, tissue remnants also impede the antimicrobial effects of root canal irrigants and medicaments and prevent intimate adaptation of the root canal filling to the dentin. Therefore, specific irrigation/disinfection procedures are necessary to remove tissue from the root canals and to kill microorganisms, respectively. The purpose of this paper was to review different aspects of a promising root canal irrigant; QMix. This is a relatively new root canal irrigant composed of traditional materials like chlorhexidine (CHX), ethylele diamine tetraacetic acid (EDTA), saline and a detergent. QMix is antibacterial, antifungal and has antibiofilm activities, it displays substantivity, smear layer removing ability; moreover, its effect on dentin and retention of fiber posts etc. has been reviewed. There have been strong reports that show the chemical design of QMix prevents precipitation of CHX when together with EDTA and mixing with sodium hypochlorite does not produce the orange-brown precipitate. Furthermore, the smear layer removal ability of QMix is comparable to that of 17% EDTA and the antibacterial activity of QMix was greater than 1% and 2% sodium hypochlorite (NaOCl) and 2% CHX.

Microorganisms are very important in the initiation of pulpo-periapical pathosis. Due to the complexity of the root canal system, the mechanical instrumentation of the root canal system should be supplemented with proper canal irrigants and medicaments. It has been revealed that due to the interactions of canal irrigants and medicaments with dentin and contents of the canal system, the antimicrobial effect of canal irrigants and medicaments in canal (ex vivo) are different from that in vitro. Furthermore, root canal irrigants may decrease the fracture resistance of dentin. The purpose of this paper was to review the data on the interactions between root canal irrigants/medicaments and dentin/root canal contents.

The amounts of apical enlargement have been a controversial issue for a long time. The enlargement of the apical part of the canal may severely impact the endodontic prognosis. Enlargement of the apical portion to a larger size may negatively affect the ability to control the filling material during root canal obturation. In addition, an open-apex increases the risk for overfilling which has been shown to be related with decreased success rate. The retreatment of a tooth with apically enlarged canal may be even impossible. Further preparation of an apically enlarged canal may increase the risk of iatrogenic errors and also excessive apical root weakness. The present article aimed to address in vitro and clinical studies on apical enlargement, effect of coronal pre-flaring on the size of the master apical file, and clinical applications of apical enlargement.

The nickel-titanium (Ni-Ti) alloys used in endodontics contain 56% Ni and 44% Ti. The 2 unique features related to clinical dentistry (i.e., shape memory effect and superelasticity) are due to the transition from austenite to martensite in Ni-Ti alloy. When a superelastic Ni-Ti alloy undergoes a low tensile loading, normal elastic behavior occurs. In fact, at higher tensile loads, the elastic stress may reach a level at which there is extended horizontal region of elastic strain. The shape-memory property of Ni-Ti is derived from an atomic arrangement different from that of alloys like stainless steel. The purpose of this paper was to review the unique features of this alloy and mechanism of corrosion.

As the root canal system shows different and complicated anatomies, mechanical instrumentation alone has not the ability to provide a bacteria-free environment in root canals. On the other aspect, necrotic tissue remaining can decrease the effects of root canal irrigants and medicaments and also interfere with the adaptation of root canal fillings to dentin. As a result, certain disinfection and irrigation procedures are required to remove the remaining tissues from the root canal area thoroughly and also be able to eliminate the microorganisms. Triple antibiotic paste (TAP) containing metronidazole, ciprofloxacin and minocycline has been proposed as a root canal medicament due to its antimicrobial effects in endodontic regenerative procedures. The purposes of this review were to determine the properties of TAP drugs and to evaluate the efficiency of TAP on the root canal disinfection, in primary and permanent teeth, along with its affection in regeneration/revascularization procedures. The biocompatibility and disadvantages of this medicament were also discussed.

The microbial biofilm is an important factor for human infection. Finding effective antimicrobial strategies should be considered for decreasing antimicrobial resistance and controlling the infectious diseases. Treatment of infected canal systems may not be able to remove all bacteria and so bacterial persistence after treatment may occur. Application of antibacterial nanoparticles may be a potential strategy to improve the elimination of bacteria from the canal. Furthermore, mechanism of action and applications of photodynamic therapy and Photon-induced photoacoustic streaming (PIPS) and GentleWave system was reviewed.

The purpose of the review was to assess the effect of root canal irrigants on dentin bonding. A PubMed-based search was conducted on the articles published from 1980 to 2016. A brief overview and reviewing the effect on dentin bonding of common root canal irrigation solutions such as sodium hypochlorite (NaOCl), chlorhexidine (CHX), ethylenediaminetetraacetic acid (EDTA), mixture of a tetracycline, acid and a detergent (MTAD) and ozone was conducted. Findings showed that, depending on the type of dentin bonding, using NaOCl may decrease, increase or not affect the bond strength. In addition, due to its broad-spectrum matrix metalloproteinase-inhibitoryeffect, CHX as well as MTAD can significantly improve the resin-dentin bondstability. However, the effect of ozone therapy on bond strength was controversial.

The most difficult clinical considertions in orthograde root canal treatment are generally related to the anatomy of the teeth. Three-canalled maxillary and mandibular premolars (mini-molars) have been reported in several studies. The purpose of this paper was to review various aspects of three-canalled premolars including incidence, clinical and radiographic diagnosis, racial predisposition, access cavity preparation, instrumentation and obturation.

Root resorption (RR) is defined as the loss of dental hard tissues because of clastic activity inside or outside of tooth the root. In the permanent dentition, RR is a pathologic event; if untreated, it might result in the premature loss of the affected tooth. Several hypotheses have been suggested as the mechanisms of root resorption such as absence of the remnants of Hertwig's epithelial root sheath (HERS) and the absence of some intrinsic factors in cementum and predentin such as amelogenin or osteoprotegerin (OPG). It seems that a barrier is formed by the less-calcified intermediate cementum or the cementodentin junction that prevents external RR. There are several chemical strategies to manage root resorption. The purpose of this paper was to review several chemical agents to manage RR such as tetracycline, sodium hypochlorite, acids (citric acid, phosphoric acid, ascorbic acid and hydrochloric acid), acetazolamide, calcitonin, alendronate, fluoride, Ledermix and Emdogain.

Using ultrasonic devices in endodontics can enhance the antibacterial and tissue dissolving ability of different root canal irrigants such as sodium hypochlorite (NaOCl) which is the most common irrigant with excellent antibacterial and tissue dissolving abilities. However, due to its high surface tension, its penetration into the irregularities of the root canal system is a challenge. The purpose of this paper was to review the different ultrasonic devices, different types of ultrasonic irrigation, the effect(s) of ultrasonic activation on the antibacterial and biofilm-removal abilities of NaOCl as well as the effect of ultrasonic activation on the smear layer removal ability of NaOCl.

Since the introduction of engine-driven nickel-titanium (NiTi) instruments, attempts have been made to minimize or eliminate their inherent defects, increase their surface hardness/flexibility and also improve their resistance to cyclic fatigue and cutting efficiency. The various strategies of enhancing instrument surface include ion implantation, thermal nitridation, cryogenic treatment and electropolishing. The purpose of this paper was to review the metallurgy and crystal characteristics of NiTi alloy and to present a general over review of the published articles on surface treatment of NiTi endodontic instruments.

Microbial biofilm is defined as a sessile multicellular microbial community characterized by cells that are firmly attached to a surface and enmeshed in a self-produced matrix of extracellular polymeric substances. Biofilms play a very important role in pulp and periradicular pathosis. The aim of this article was to review the role of endodontic biofilms and the effects of root canal irrigants, medicaments as well as lasers on biofilms. A Medline search was performed on the English articles published from 1982 to 2013 and was limited to papers published in English. The searched keywords were “Biofilms AND endodontics”, “Biofilms AND sodium hypochlorite”, «Biofilms AND chlorhexidine», «Biofilms AND MTAD», «Biofilms AND calcium hydroxide», “Biofilms AND ozone”, “Biofilms AND lasers” and «Biofilms AND nanoparticles». The reference list of each article was manually searched to find other suitable sources of information.

Ozone is a triatomic molecule consisting of three oxygen atoms. It is applied to oral tissues in the forms of ozonated water, ozonated olive oil and oxygen/ozone gas. This paper presents a brief review on the chemistry of ozone as well as its medical and dental applications focusing on its use in endodontics. Ozone’s antimicrobial activity, its effect on dentin bonding, toxicity and contra-indications are also reviewed.

Microorganisms play a major role in the initiation and perpetuation of pulpal and periapical disease. In order to predictably achieve a bacteria-free root canal system, it is necessary to use intracanal medicaments. Calcium hydroxide is the most common intracanal medicaments. It is effective against primary infections. However, its effectiveness against Enterococcus faecalis and Candida albicans is controversial. On the other hand, chlorhexidine is a potent agent against Enterococcus faecalis and Candida albicans. For this reason, it has been combination of calcium hydroxide and chlorhexidine has been suggested as an intracanal medicament. The purpose of this article was to a brief review antimicrobial efficacy of calcium hydroxide, chlorhexidine, and their combination.

The purpose of this study was to compare the inhibitory effect of bovine serum albumin (BSA) and hydroxyapatite (HA) on the antibacterial activity of white-colored MTA (WMTA) against Staphylococcus (S.) aureus and Streptococcus (S.) mutans after 24 and 72 hours. All materials were prepared according to the manufacturer’s directions immediately before testing. The antibacterial effect of each group (WMTA, WMTA+BSA and WMTA+HA) was determined by measuring the diameter of zone of inhibition in millimeters after incubation at 37°C for 24 and 72 hours in a humid atmosphere. Each test was repeated three times. Data were analyzed using ANOVA and Tukey’s test. In the 24 hours samples as well as in 72 hours samples, the antibacterial activity of MTA+HA group was significantly greater than two other groups against S. aureus (P < 0.05). However, the antibacterial activity of MTA+HA group against S. mutans was not significantly different from the MTA group in 24 hours as well as 72 hours samples. BSA reduced the antibacterial activity of MTA against both tested bacteria in the 24 and 72 hour samples (P < 0.05). The products studied exhibited antibacterial activity. However, in both time intervals, the MTA+HA group exerted the greatest activity against S. mutans and S. aureus.