The purpose of endodontic therapy is to preserve the patient's natural teeth without compromising the patient's local or systemic health. Calcium hydroxide has been included in several materials and antimicrobial formulations that are used in several treatment modalities in endodontics, such as inter-appointment intracanal medicaments. The purpose of this article was to review the antimicrobial properties of calcium hydroxide in endodontics. Calcium hydroxide has a high pH (approximately 12.5-12.8) and is classified chemically as a strong base. The lethal effects of calcium hydroxide on bacterial cells are probably due to protein denaturation and damage to DNA and cytoplasmic membranes. Calcium hydroxide has a wide range of antimicrobial activity against common endodontic pathogens but is less effective against Enterococcus faecalis and Candida albicans. Calcium hydroxide is also a valuable anti-endotoxin agent. However, its effect on microbial biofilms is controversial.

Ethylenediaminetetraacetic acid (EDTA) is a chelating agent can bind to metals via four carboxylate and two amine groups. It is a polyamino carboxylic acid and a colorless, water-soluble solid, which is widely used to dissolve lime scale. It is produced as several salts, notably disodium EDTA and calcium disodium EDTA. EDTA reacts with the calcium ions in dentine and forms soluble calcium chelates. A review of the literature and a discussion of the different indications and considerations for its usage are presented.

Biofilms and microbial aggregates are the common mechanisms for the survival of bacteria in nature. In other words, the ability to form biofilms has been regarded as a virulence factor. Microbial biofilms play an essential role in several infectious diseases such as pulp and periradicular pathosis. The aim of this article was to review the adaptation mechanisms of biofilms, their roles in pulpal and periapical pathosis, factors influencing biofilm formation, mechanisms of their antimicrobial resistance, models developed to create biofilms, observation techniques of endodontic biofilms, and the effects of root canal irrigants and medicaments as well as lasers on endodontic biofilms. The search was performed from 1982 to December 2010, and was limited to papers in English language. The keywords searched on Medline were "biofilms and endodontics," "biofilms and root canal irrigation," "biofilms and intra-canal medicament," and "biofilms and lasers." The reference section of each article was manually searched to find other suitable sources of information.

Aim:The purpose of this review is to address the smear layer removing the ability of root different canal irrigants including ethylenediaminetetraacetic acid (EDTA), a mixture of tetracycline, acid and detergent (MTAD), tetraclean, citric acid, Q-Mix, maleic acid, and smear clear.Background: Smear layer is a layer which is produced during instrumentation. It contains both organic and inorganic materials. It may also contain bacteria and their byproduct considering the root canal situation. This layer may prevent the penetration of the healing material introduced to the canal to the interior of the dentinal tubules. In addition, it can affect the adaptation of sealing materials to the root canal walls. Review results:The smear layer removal ability of MTAD is superior and faster than EDTA. Tetraclean is similarly composed of an acid, an antibiotic, and a detergent. The presence of doxycycline is believed to help the smear layer removal ability of these irrigants. Antibiotics such as tetracycline had similar smear layer removal ability as even citric acid. EDTA is an amino acid with a chelating ability that sequestrates metal ions. Some believed EDTA smear layer removing ability is better than MTAD, tetraclean, SmearClear, and 20% citric acid which is controversial in case of comparison between MTAD and EDTA. Phosphoric acid is efficient enough to be comparable to EDTA in removing the smear layer. Maleic acid is an organic compound with acid etching smear layer removal. Its ability seems to be similar or even better than EDTA. Citric acid as another organic acid is believed to be used as smear removing agent. HEBP is another chelating agent that can be used in combination with NaOCl; however, HEBP is a weak decalcifying agent compared to EDTA and hence cannot be applied as a mere final rinse. QMiX is a combination of CHX, EDTA, and detergent and should be used at final rinse. It is believed that QMiX is as efficient as EDTA. Smear clear is a 17% EDTA solution including an anionic and cationic (cetrimide) surfactant. The ability of QMiX is similar to EDTA. Conclusion:There are different canal irrigation solutions with various smear layer removal ability that some should be used as a mere final rinse and some should not. Clinical significance:The usage of canal irrigation solutions depends on the clinical situation and preference of the dentists. This study provides a good guide for clinician of the field.

Glass ionomer cements (GICs) are biocompatible and have capacities to release fluoride and to bond to dentine, and thus are appropriate for use in endodontics. This paper reviews the composition and properties of different GICs, including their biocompatibility and antibacterial activity, their applications as intraorifice barriers and root canal sealers, and their use in the repair of root perforations, root-end fillings and temporary coronal restorations.

Introduction:As the root canal system considered to be complex and unpredictable, using root canal irrigants and medicaments are essential in order to enhance the disinfection of the canal. Sodium hypochlorite is the most common irrigant in endodontics. Despite its excellent antimicrobial activity and tissue solubility, sodium hypochlorite lacks some important properties such as substantivity and smear layer removing ability.Objective:The aim of this review was to address benefits and drawbacks of combining sodium hypochlorite with other root canal irrigants and medicaments.Discussion:According to the reviewed articles, NaOCl is the most common irrigation solution in endodontics. However, it has some drawbacks such as inability to remove smear layer. One of the drawbacks of NaOCl is its inability to remove the smear layer and lack of substantivity.Conclusion:The adjunctive use of other materials has been suggested to improve NaOCl efficacy. Nevertheless, further studies are required in this field.

All products studied exhibited antibacterial activity. However, in 24-h and 7-day samples, AH-26 exerted the greatest activity against both organisms tested.

Use of an appropriate root canal irrigant is essential during endodontic treatment, due to the complex and unpredictable anatomy of the root canal system and limitations in the mechanical instrumentation techniques used to obtain a clean, bacteria-free canal. Several irrigants, such as sodium hypochlorite, chlorhexidine, hydrogen peroxide, and normal saline, have been proposed as canal system irrigants in endodontic treatment. The widely used endodontic irrigant chlorhexidine is a positively charged lipophilic/hydrophobic molecule that interacts with phospholipids and lipopolysaccharides on the bacterial cell membrane. In endodontics, its mode of antibacterial activity is determined by its concentration (0.2% or 2%). This article reviews findings from available endodontic studies on the antibacterial, antifungal, and antibiofilm activities of chlorhexidine. (J Oral Sci 56, 99-103, 2014)