Biodentine

More documents

Recommendations

Info

1.2 - Formulation of <strong>Biodentine</strong> In order to reach a formulation with a short setting time (12 minutes) and high mechanical properties in the range of natural dentine, calcium silicates could not be used alone. Usually calcium silicate cements have setting times in the range of several hours, which is too long in most of the protocols in clinical practice. Increasing the setting time was achieved by a combination of different effects. First, particle size greatly influences the setting time, since the higher the specific surface, the shorter the setting. Also, adding calcium chloride to the liquid component accelerates the system. Finally, the decrease of the liquid content in the system decreases the setting time to harden within 9 to 12 minutes. Powder Tri-calcium Silicate (C3S) Main core material Di-calcium Silicate (C2S) Second core material Calcium Carbonate and Oxide Filler Iron Oxide Shade Zirconium Oxide Radiopacifier Liquid Calcium chloride Accelerator Hydrosoluble polymer Water reducing agent Reaching high mechanical strength is also quite difficult for these systems. The first cause of low mechanical properties of Portland cements are the aluminate components, which make the product fragile. Septodont controls the purity of the calcium silicate through the Active Biosilicate Technology which consists in eliminating aluminates and other impurities. The second axis of formulation was to adjust the particle size distribution in order to reach an optimal powder density. The additional charge system selected was calcium carbonate, for both its biocompatibility and calcium content. The paradox of calcium silicate systems is also that water, which is essential for the hardening of the product, can also affect the strength of the material. On the hand, excess water in the system will create some remaining porosity, significantly degrading the macroscopic mechanical resistance, but on the other hand decreasing the water content leads to reducing the possibility of a homogenous mix. The addition of hydrosoluble polymer systems described as “water reducing agents” or super plasticizers, helps in maintaining the balance between low water content and consistency of the mixture. Radiopacity is obtained by adding zirconium oxide to the final product. 7
8 ❷ Physico-chemical 2.1 - Setting Time There are several methods to evaluate the setting of dental materials. The first one is based on the macroscopic evaluation of the resistance of a needle to penetrate the surface of the material: when the needle does not leave a trace on the surface of the material, it corresponds to the setting time. This is the principle of the ISO standard 9917. An alternative instrumented and more objective method can be used especially to help in the selection of different formulations: the use of a rheometer (Nonat and Franquin, 2006). Method: features Dynamic rheometry tests were performed to determine the characteristics of each material during their workability (working and setting times) as well as the rate of building early mechanical resistance. These tests consisted in measuring, by a viscoelastometry, the constraint transmitted by the sample, when a sinusoidal strain is applied. An ARES strain-controlled rheometer was used (Rheometric Scientific Inc., Piscataway, US). After mixing, the sample was inserted between the two striated parallel plates, 6 mm in diameter, with a 2 mm gap. Only the lower plate was maintained at the controlled temperature of 37.5°C, and a closed chamber maintained the temperature of the entire sample at 100% relative humidity to prevent drying. The experimental conditions were as follows: oscillation frequency: 1 radian per second, applied strain: 0.0005%. Under these conditions, the applied strain is less than the critical strain beyond which the structure of the cement paste is altered (about 0.0015%), and the transmitted stress is proportional to the strain. This system can therefore be used to measure the evolution of the elastic modulus G’ of the material, without any modification of the structure of the material. This instrumented method was used to determine the setting time of the <strong>Biodentine</strong> Formulation (Fig.1) and to compare it to a classical glass ionomer (Fuji IX – GC) and ProRoot ® MTA (Dentsply). The initial setting time was determined at the moment when the elastic modulus begins to increase (10MPa). The final setting time was determined as the elastic modulus reached 100MPa. The time between the mixing and the initial setting corresponds to the working time.
Page 1 and 2: R&D Department Biodentine Active B
Page 3 and 4: 4 Introduction Biodentine was devel
Page 5: 6 1.1 - Setting reaction The calciu
Page 9 and 10: 10 2.2 - Density and Porosity The m
Page 11 and 12: 12 (O’Brien 2008)). This maturati
Page 13 and 14: 14 ❸ The quality and durability o
Page 15 and 16: 16 3.2 - Resistance to microleakage
Page 17 and 18: 6 18 Z 250 Optibond Solo+ Biodentin
Page 19 and 20: 20 ❹ Outstanding biocompatibility
Page 21 and 22: 22 4.3 - Genotoxicity tests (ISO 74
Page 23 and 24: 24 ❺ Evidence based bioactivity T
Page 25 and 26: 26 The inflammatory process had dis
Page 27 and 28: 28 To conclude, Biodentine enhances
Page 29 and 30: 30 During the follow-up, the restor
Page 31 and 32: 32 6.3 - Biodentine is used as an e

Biodentine

Create successful ePaper yourself

Delete template?

Save as template?