Mineral Trioxide Aggregate (MTA)

Mineral Trioxide Aggregate (MTA) List

The main components of mineral trioxide agglomerate(MTA) are tricalcium silicate, dicalcium silicate, tricalcium aluminate and tetracalcium aluminate, which can release a large amount of calcium ions. Since the composition of MTA is similar to that of tooth tissue, it has good biocompatibility, curability, X-ray blocking, antibacterial, sealing and biological activity. In vivo and in vitro experiments have confirmed that MTA can effectively promote the regeneration of hard tissues and is non-toxic to tissues. Its long-lasting sealing greatly improves the success rate of lateral penetration repair and root tip filling. MTA can affect bone resorption and reconstruction and promote the healing of lesions by regulating the secretion of cytokines, activating the activity of extracellular signal-regulated kinases and promoting the expression of osteocalcin. MTA is a new dental material with great potential.

Applications:

The effect of MTA in inducing the formation of restorative dentin is better than calcium hydroxide, and it is a good capping agent. And MTA as an inducer for apexplasty can avoid the uncertainty of treatment time and sealing effect caused by the use of traditional Ca(OH)₂₎. MTA is a superior material for the treatment of endodontic diseases and is widely used in dentistry.

• Pulp capping: MTA is superior to calcium hydroxide in terms of cellular and molecular biological performance and long-term effects of restorative dentin formation. After pulp capping, it is found that MTA can form a new continuous and complete dentin bridge compared with calcium hydroxide, the inflammation of surrounding tissues is relatively light, and the long-term effect is better than calcium hydroxide. In in vitro experiments, MTA has the ability to promote the differentiation of normal dental pulp cells into dental tissues. Therefore, the success rate of MTA capping is higher than calcium hydroxide, and the effect of MTA capping is better than calcium hydroxide, so MTA is more suitable for direct capping surgery.
• Pulpotomy: The clinical effect of traditional pulp capping agent calcium hydroxide after devitrification is slightly inferior to that of MTA, but the application effect in partial pulpotomy is good. In vitro studies have found that after direct contact between MTA and viable pulp cells, MTA can induce the differentiation of dental pulp cells into odontoblasts, and MTA can promote the proliferation and differentiation of dental pulp in permanent and deciduous teeth.
• Apexification: Apexification is mainly used in young permanent teeth before the roots are completely formed. On the basis of infection control, drugs and surgical methods are used to preserve the vital pulp of the root tip, so that the patient's root can continue to develop and the apical foramen can be closed. Clinical studies have found that the success rate of apexectomy using MTA can be as high as 93%. Therefore, MTA is an ideal root tip induction molding material.
• Apical sealing: During root canal treatment, the sealing of 1/3 of the root apex is particularly important in root canal filling. Traditional materials, such as gutta-percha tips, need to be used with root filling paste to fill the root canal tightly, but the root filling paste will gradually be absorbed over time. At this time, the filling material will form a gap with the root canal wall. Root canal sealing becomes worse and the risk of microleakage is greatly increased, which affects the effect of root canal treatment. Studies have shown that MTA can better make up for the lack of antibacterial properties of the gutta percha, and the use of MTA as a root canal sealant can be closely combined with the root canal wall to achieve a good root canal sealing effect and increase the long-term root canal treatment effect. In addition, when the apatite crystals in the MTA come into contact with the dentin, chemical bonding occurs, which increases the sealability of the root tip. In addition, the fine hydrophilic particles in MTA make MTA hydrate in a humid environment, and its polymerization shrinkage can be compensated by hygroscopic expansion, thereby greatly reducing the possibility of edge leakage after sealing.

Figure 1. MTA is used in root canal therapy.

References

1. Ignacio Medina-Fernandez and Adam D. Celiz. Acellular biomaterial strategies for endodontic regeneration [J]. Biomater. Sci., 2019, 7, 506–519.
2. Ziji Ling, Yalin He, Haowen Huang, Xiaoqi Xie, Quan-li Li and Chris Ying Cao. Effects of oligopeptide simulating DMP-1/mineral trioxide aggregate/agarose hydrogel biomimetic mineralisation model for the treatment of dentine hypersensitivity [J]. J. Mater. Chem. B, 2019, 7, 5825-5833.
3. Feng Zhang, Xianyan Yang, Chen Zhuang, Lin Wang, Xin-Hua Gu, Zheng Shen, Sanzhong Xu, Changyou Gaob and Zhongru Gou. Design and evaluation of multifunctional antibacterial ion-doped b-dicalcium silicate cements favorable for root canal sealing [J]. RSC Adv., 2016, 6, 19707–19715.