When tested in bulk without a main core, both 'sealer type' and 'SBF storage' were significant in affecting push-out results. The ProRoot Endo Sealer demonstrated the presence of spherical amorphous calcium phosphate-like phases and apatite-like phases (i.e. ex vivo bioactivity) after SBF storage.

Choosing an endodontic sealer for clinical use is a decision that contributes to the long-term success of non-surgical root canal treatment (NSRCT) 1) . Sealers are used as a thin tacky paste which functions as a lubricant and luting agent during obturation, allowing the core obturation material, such as gutta-percha points or other rigid materials, to slide in and become fixed in the canal 2,3) . Sealers can fill voids 4) , lateral canals 5) , and accessory canals where core obturation materials cannot infiltrate 6,7) . If the sealer does not perform its function, microleakage may cause NSRCT failure via clinically undetectable passage of bacteria, fluids, molecules or ions between the tooth and restorative material 8,9) . Knowing the qualities and characteristics of an endodontic sealer is critical to determining the best selection and application for each clinical case.Endodontic sealers are categorized by composition based on setting reaction and composition: zinc oxideeugenol, salicylate, fatty acid, glass ionomer, silicone, epoxy resin, tricalcium silicate, and methacrylate resin sealer systems (Table 1). Some novel sealers contain fillers or ceramic powders including calcium hydroxide, mineral trioxide aggregate (MTA), and calcium phosphate; however, they are fundamentally composed of the above sealer matrices. Until recently, many review articles were published within sealer types [10][11][12][13][14][15][16] . However, few reviews have been published that cover all sealer types 17,18) . Therefore, in this comprehensive review, a historical perspective of each sealer type will be discussed first, followed by a description of the properties of all sealer types, such as setting time and solubility, sealing ability, antimicrobial activity, and biocompatibility and cytotoxicity. Sealer attributes such as the rheology 19) , radiopacity 20) , and tooth discoloration [21][22][23] have been shown to be satisfactory and will not be discussed in detail. CURRENT ROOT CANAL SEALERS AND HISTORY Chelate formationMany dental luting agents set by way of a chelation reaction, the formation of metal complexes with polydentate (usually organic) ligands 24) . Two of the most common chelates used in dentistry are eugenolates and salicylates. For eugenolates, the setting reaction starts with water that hydrolyzes the zinc oxide to form zinc hydroxide. The zinc hydroxide and eugenol chelate and solidify 25) . For salicylates, the ion is calcium, usually formulated using calcium oxide. Although uncommon, fatty acids have also been used as ligands for chelate sealers, in conjunction with zinc oxide.

No abstract

Introduction The treatments for which mineral trioxide aggregate (MTA)-based materials can be used in dentistry are expanding. Smaller particle size and easier handling properties have allowed the advent of tricalcium silicate sealers including EndoSequence BC Sealer (Brasseler USA, Savannah, GA), QuickSet2 (Avalon Biomed, Bradenton, FL), NeoMTA Plus (Avalon Biomed), and MTA Fillapex (Angelus, Londrina, Brazil). The objective of this study was to measure the tubule penetration with these sealers using continuous wave (CW) and single-cone (SC) obturation techniques. Methods Eighty single-rooted teeth were randomly divided into 8 groups of 10 and obturated with 1 of the previously mentioned sealers mixed with trace amounts of rhodamine using either the CW or SC technique. Teeth were sectioned at 1 mm and 5 mm from the apex and examined under a confocal laser microscope. The percentage of sealer penetration and the maximum sealer penetration were measured. Results The tricalcium silicate sealers penetrated tubules as deep as 2000 μm (2 mm). The percentage of sealer penetration was much higher 5 mm from the apex, with many specimens having 100% penetration for both SC and warm vertical techniques. MTA Fillapex, a resin-based sealer with less than 20% MTA particles, had significantly greater tubule penetration with a warm vertical technique versus the SC technique at the 1-mm level. Conclusions Within the limitations of this study, the CW and SC techniques produced similar tubule penetration at both the 1-mm and the 5-mm level with the tricalcium silicate sealers BC Sealer, QuickSet2, and NeoMTA Plus.

Fluoride-releasing restorative materials are available for remineralization of enamel and root caries. However, dentin remineralization is more difficult than enamel remineralization due to the paucity of apatite seed crystallites along the lesion surface for heterogeneous crystal growth. Extracellular matrix proteins play critical roles in controlling apatite nucleation/growth in collagenous tissues. This study examined the remineralization efficacy of mineral trioxide aggregate (MTA) in phosphate-containing simulated body fluid (SBF) by incorporating polyacrylic acid and sodium tripolyphosphate as biomimetic analogs of matrix proteins for remineralizing caries-like dentin. Artificial caries-like dentin lesions incubated in SBF were remineralized over a 6-week period using MTA or MTA containing biomimetic analogs in the absence or presence of dentin adhesive application. Lesion depths and integrated mineral loss were monitored with micro-computed tomography. Ultrastructure of baseline and remineralized lesions were examined by transmission electron microscopy. Dentin remineralization was best achieved using MTA containing biomimetic analogs regardless of whether an adhesive was applied; dentinal tubules within the remineralized dentin were occluded by apatite. It is concluded that the MTA version employed in the study may be doped with biomimetic analogs for remineralization of unbonded and bonded artificial caries-like lesions in the presence of SBF.