 Hello everyone, welcome back to another session in dentistry and work. So, today's topic in conservative dentistry is MTA that is mineral trioxide aggregate. So, as we all know the quest for new materials are never-ending especially in the field of dental science. So, various materials have been formulated, tested and standardized to obtain maximum benefit for good clinical performance. So, one such material is MTA. So, which was introduced by Dr. Mahmud Tarabinejad in 1993 in California. So, it was originally formulated to provide the physical properties, setting requirements and characteristics which is necessary for an ideal repair and medicament material. Okay, so it is mainly for the repair and medicament. So, it has proven that MTA exhibits good sealing ability, excellent long-term prognosis, relative ease of manipulation, good biocompatibility and tissue regeneration. So, in 1998 MTA has been approved by the US Food and Drug Administration that is FTA. So, we have basically three powder ingredients in MTA. First one is Portland cement which is a very commonly used protapax filling material. But it is one of the ingredients that is it constitute around 75 percentage then bismuth oxide to improve the radio opacity and gypsum 5 percentage. Okay. So, if we say chemical composition it consists of tricalcium silicate, tricalcium aluminate, tricalcium oxide, silicate oxide and bismuth oxide. So, its composition is almost like Portland cement but only the additional thing is mainly the bismuth oxide to improve the radio opacity. So, the particle sizes are smaller and uniform in size whereas the particle size of Portland cement vary in size but our MTA has more smaller and regular in size. So, we have basically two types of MTA. The first one is gray MTA and second one white MTA. So, GMTA or WMTA. So, the gray MTA why that peculiar color gray is because of the ferrous oxide. Okay, ferrous oxide gives that gray color. So, it contains tetrachalcium alumino ferrate nothing but ferrous oxide which is responsible for this gray discoloration. So, it can cause discoloration of teeth so that it is not commonly used in anterior tooth and it has got larger particles and it is having larger particles and longer setting time but good compressive strength whereas the white MTA the ferrous oxide is replaced by magnesium oxide. Okay, so it has magnesium oxide. So, there is no problem of tooth discoloration it has got lesser particle size and shorter setting time and similarly it has got lesser compressive strength. Next about the mixing of MTA. Okay, so it is commonly followed the three is to one pattern the MTA paste is obtained by mixing three parts of powder and one part of water. Okay, so to get a party like consistency. Okay, we can mix it on a paper or even on a glass lap using a plastic or metal spatula then this mix is placed in the desired location and condensed lightly with moistened cotton pellet. So, that is about a mixing. Now, let's see the properties of MTA. So, the first about compressive strength compressive strength. So, the compressive strength it takes an average three to four hours for the MTA material to completely solidify. So, it has shown that once it is set its compressive strength equal to IRM or super EBA but less than amalgam. So, this IRM and super EBA restorative materials specially the rotent restorative material retrograde filling materials. So, the compressive strength is equal to IRM and super EBA but less than amalgam. So, the compressive strength of MTA within 24 hours of mixing was about 40 megapascal but it increases to 67.3 megapascal after 21 days. Okay, this is 24 hours. So, this is a compressive strength. Okay. So, the gray MTA exhibited greater compressive strength than whiter MTA. Now, the pH. So, the second property is pH. The initial pH is 10.2 very alkaline pH. Again, it goes to 12.5 after three hours. Okay, that is a second property. Third property is radio opacity. Radio opacity it is actually less radio opaque than IRM and super EBA amalgam or Gattapacham and it has similar radio density as Zinc Oxide Eugenol. Okay, it's radio density is similar to Zinc Oxide Eugenol but lesser than the other materials. So, the mean radio opacity of MTA is 7.17 millimeter of equivalent thickness of aluminum which is sufficient to make it easy to visualize radiographically. The next property is solubility. Okay, the fourth property is solubility. So, the MTA shows basically no sign of solubility and the solubility might increase if we add more water during the mixing. So, the set MTA when exposed to water release water. So, it releases calcium hydroxide which might be responsible for its cementogenesis property. So, that is solubility. The next thing is marginal adaptation. Marginal adaptation and sealing ability. So, it seals well. So, MTA expands during setting which may be the reason for its excellent sealing ability. So, its thickness of about 4 mm is sufficient to provide a good sealing, sealing of the root apex. Okay. So, it has also got antibacterial and anti-fungal properties. So, it is basically works against bacteria groups such as intracoccus, ficalis, streptococcus, sankus, pseudomonas, and E. coli, candida albicans, staphylococcus, epidermis, all these bacteria will be destroyed. So, the seventh property is biocompatibility. So, it is very biocompatible and it is not mutagenic and is much less cytotoxic compared to superebian IRM. So, this supports the superiority of MTA over formacosol as a pulpotomy medicament. Okay. So, that is a biocompatibility. And next property is reaction with other dental material. So, MTA does not react or interfere with any other restorative material. GIC or composite resin which use a permanent filling material, do not affect the setting of MTA when placed over it. Okay. So, the possible interactions might occur when MTA cement is combined with the other materials during endodontic treatment. That is chloroxidine. It might cause difficulties for correct setting. Sodium hypochloride might cause a shorter time of setting. Saline might cause a longer time of setting. Lignokine, again, longer time of setting. And the next property is tissue regeneration. Tissue regeneration is MTA is capable of activation of cementor blasts and production of cement. So, it consistently allows for overgrowth of cement and also facilitates regeneration of periodontal ligament. And it allows bone healing and eliminates clinical symptoms in many cases. So, the last one we have is the mineralization. The 10th property is mineralization. So, just like calcium hydroxide, it induces dentain bridge formation. Okay. That is the most important one, dentain bridge formation. So, the heart tissue bridge deposited next to MTA, it is mainly because of the sealing property, biocompatibility, alkalinity and other properties associated with this material. So, the dentain bridge that is formed with MTA is faster with good structural integrity and more complete than when compared to the calcium hydroxide. Okay. So, it proves to be a better at stimulating reparative dentain formation. So, it resulting in less inflammation, hyperemia, necrosis, as well as a good thicker dentain bridge with more frequent odendoblastic layer formation. So, when we compare with calcium hydroxide, so the first property is heart tissue formation. Heart tissue formation is not very much in calcium hydroxide, but MTA gives root and induction. Okay. Root and induction. Then the calcified bridge. So, it is continuous with dentain and it is very fast. It is not continuous, not continuous and it is slow. The biocompatibility is high, biocompatibility. High here, calcium hydroxide, it is low. Degree of inflammation, it is high, it is low here. Inflammation. Then the setting. Setting is not very hard, but it is hard here. Then the pH is both having high pH, it is alkaline pH. Solubility. Solubility is a better property. MTA is highly insoluble, but this is partially soluble. Calcium hydroxide is partially soluble. Permeability. It is non permeable, whereas the calcium hydroxide is permeable to fluids. Then resorption. MTA is non-resorbable. Okay. Non-resorbable, but here it is. It increases the rate varies with density. Epical closure is very good with MTA, but unpredictable with calcium hydroxide. So, the basic clinical application of MTA are, as we all know, it is mainly used as a root and filling material. Epical closure. So, mainly is direct pulp capping. Then pulpitomy. Focation. Treatment. Then root perforation. Then the obturation, that is retrograde obturation. Then apexogenesis and apexification. And also radical resorption cases. So, all these cases are mainly the root repair material. So, that's all about MTA, mineral trioxide aggregate. So, we learned about the properties, its application, its setting, and little bit about its composition and introduction. So, this is very commonly asked to show up now in conservative industry. Hope you understood the small concept of MTA. I will come over to your topic in conservative industry. Thank you.