Graphical Abstract
ABSTRACT
Aim: This study aimed to use the micro-computed tomography to evaluate the interfacial adaptation and the presence of gaps of NeoMTA Plus, BioRoot RCS, and MTA in the root-end cavities. Methodology: Thirty standardized bovine roots measuring 15 mm in length were selected. Chemical-mechanical preparation was performed up to instrument #80 and obturation with the cold lateral compaction technique with cement based on zinc oxide and eugenol. The roots were kept at 37º C for seven days. Afterward, apicectomy of the apical 3mm and a root-end filling cavity was performed at 3mm depth. Micro-computed tomography (micro-CT) was performed to measure the volume of the retroactivity. The roots were divided by stratified randomization into three groups according to the retro-end filling material: NeoMTA Plus, BioRoot RCS, and MTA. A new micro-CT was performed to assess the presence of voids in the root-end filling material and between it and the canal wall. One-way ANOVA and Tukey tests were performed using the BioEstat 4.0 program. Results:  There was no difference in the initial volume values of the root-end cavities (P > 0.05). After the insertion of root-end filling materials, the most significant volumes of voids were observed in the NeoMTA Plus group (P < 0.05), with no difference for the BioRoot RCS and MTA Angelus groups (P > 0.05). Conclusion:  Micro-computed tomography showed that MTA and BioRoot RCS have better interfacial adaptation and presented fewer number of gaps than NeoMTA Plus when used as root-end filling materials.
Keywords: Endodontics; Apical surgery; Root-end filling material; Micro-computed tomography.
INTRODUCTION
Apical surgery is indicated in cases where the conventional endodontic treatment has failed or in cases of impossibility of access to the root canal through the coronary (DEL FABBRO et al., 2016). The technique consists of the surgical removal of the pathological periradicular tissue, followed by resection of the root apex, preparation of a cavity in the apical portion of the root canal, and filling this space with a suitable root-end filling material to seal this region (GUTMANN; HARRISON,1991). This material aims to prevent the infiltration of bacteria and their products, allowing the reorganization of the periodontal ligament space. (JOHNSON,1999; KIM; KRATCHMAN, 2006)
A root-end filling material choice that has adequate biological and physical-chemical characteristics is essential for a successful apical surgery (DEL FABBRO et al., 2016). The material’s resistance to displacement and sealing capacity is included among the physical-chemical characteristics. The first material based on calcium silicate was developed in the 1990s to be used as a root-end filling material, called Mineral Trioxide Aggregate. (MTA) (LEE; MONSEF; TORABINEJAD, 1993) and marketed as ProRoot MTA (Tulsa Dental Products, Tulsa, OK, EUA) in gray coloring. Adding a bismuth oxide radiopacifier is the differential component of this product for Portland cement (FUNTEAS; WALLACE; FOCHTMAN, 2003). MTA has hydraulic properties, sealing ability, bioactivity, and biocompatibility (CAMILLERI, 2015a; PRATI; GANDOLFI, 2014).
MTA can be found on the market in gray and white colors. It began to be produced in Brazil in 2001 by Angelus company (MTA Angelus; Angelus Produtos Odontológicos, Londrina, Brasil) in gray and, in 2004, in white (SARZEDA et al.,2019). The sandy consistency makes handling the material and its application challenging. MTA also presents a lengthy setting time and can lead to coronal and gingival darkening (BORTOLUZZI et al.,2007; SARZEDA et al.,2019). However, recent studies suggest that some physical and chemical characteristics should be improved (SHETTY; HIREMATH; YELI, 2017; Ber, Hatton, Stewart, 2007).
New calcium silicate-based materials have been developed and commercialized to improve the characteristics of MTA. These materials have been called ”bioceramic cement” or ”MTA-like” due to their composition similar to MTA (CAMILLERI, 2015a; COOMARASWAMY; LUMLEY; HOFMANN, 2007).
BioRoot RCS (Septodont, Saint- Mouer-Dis-Fosses, France) is a powder (tricalcium silicate, zirconia oxide, povidone) and a liquid (hydrated calcium chloride, polycarboxylate, and purified water). According to the manufacturer, this cement was developed to combine high biocompatibility with better physical properties such as ease of handling, resistance to compression, and better biological. As root-end filling material, 1.5 scoops of powder must be mixed with five liquid drops. Even when manipulated in a denser thickness, it has good biological properties and little cytotoxicity (BONAFÉ, 2021; ALSUBAIT et al.,2018). BioRoot RCS has zirconium oxide as a radiopacifier, which is not correlated with changes in the color of the dental crown (SIBONI et al., 2017). BioRoot RCS can also induce hard tissue formation due to its alkaline pH and high release of calcium ions (SIBONI et al., 2017; SFEIR et al., 2021; DONNERMEYER et al., 2018). A systematic review of in vitro studies showed (Donnermeyer et al., 2018) high biocompatibility, low cytotoxicity, and satisfactory clinical performance.
NeoMTA Plus (Avalon Biomed Inc. Bradenton, FL, USA) is an evolution of MTA Plus (Avalon Biomed Inc. Bradenton, FL, USA). The primary difference is that NeoMTA Plus features tantalum oxide as a radiopacifying agent, while MTA Plus presents bismuth oxide. NeoMTA Plus is formed by mixing powder and liquid. The powder contains tricalcium silicate, dicalcium silicate, tantalum oxide, calcium aluminate, and calcium sulfate. A water-based gel forms the liquid with thinner water-soluble agents and polymers, which provides better handling of the cement (EID et al., 2014; MCMICHAEL; PRIMUS; OPPERMAN, 2016).
Small powder particles also improve handling (Camilleri, Formosa, and Damidot, 2013). Neo MTA Plus also stimulates hard tissue deposition (CAMILLERI, 2015a). It is a biocompatible material with low cytotoxicity (PINHEIRO et al., 2018; QUINTANA et al., 2018).
This study aims to evaluate, using micro-CT, the number of empty spaces (i.g. voids and gaps) of NeoMTA Plus, BioRoot RCS, and MTA (Angelus, Londrina, Brazil) in root-end cavities of bovine teeth.