Tricalcium Silicate-based Endodontic Cements - Properties and Modifications

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From the course by The University of Hong Kong

Materials in Oral Health

103 ratings

The University of Hong Kong

Materials in Oral Health

103 ratings

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From the lesson

Modern Composites and Cements

An Introduction to Dental Cements5:06

Introduction to Glass Ionomer Cements (GIC) and Resin-modified Glass Ionomer Cements (RMGIC)4:06

Tricalcium Silicate-based Endodontic Cements - Properties and Modifications5:17

Tricalcium Silicate-based Endodontic Cements - Radiopacifier2:49

Tricalcium Silicate-based Endodontic Cements - Modifications in Mixing Liquids and Additives7:01

Tricalcium Silicate-based Endodontic Cements - Hydraulic Properties and Bioactivities3:26

Meet the Instructors

Jukka Pekka Matinlinna
Professor in Dental Materials Science, Head of Unit
Faculty of Dentistry, The University of Hong Kong
James Kit Hon Tsoi
Assistant Professor in Dental Materials Science, Assistant Dean of Electives and Experiential Learning
Faculty of Dentistry, The University of Hong Kong

Good day, I am Professor Josette Camilleri,

Associate Professor at the University of Malta.

Today, we will be discussing tricalcium silicate-based endodontic cements.

Tricalcium silicate-based endodontic cements

can be based on Portland cement

and they can also be based on tricalcium silicate.

The presentation clinically,

usually are cements which are presented as powder and liquid,

they can be presented as pastes and putty,

they can even come in sealer forms,

and also as pulp-capping materials.

The tricalcium silicate can be pure tricalcium silicates,

which are manufactured in the labs

by sintering, by sol-gel methods,

or else they can be also the Portland type, which comes in sets

but usually are bought from the construction industry.

It is a very, very cheap material

which can be used in dentistry

and packaged in small packets at a higher price.

The main interest with this material is

that when the material is mixed with water,

which is the main mixing liquid of this cement type,

you form calcium hydroxide as part of the reaction.

As all clinicians know,

calcium hydroxide is a very important material in clinical dentistry,

as it is used for most endodontic procedures

and pulp-capping procedures.

With this material, this calcium hydroxide is formed

as part of the hydration of both Portland cement

and tricalcium silicate cement.

When the material hydrates, you will have the main particle

which is the cement particle around which you get a reaction rim,

where you get calcium silicate hydrate

which is the main material mass,

and also you will get soluble calcium hydroxide.

If you look at an X-ray diffractogram,

which is shown here, you will find that

when you have the powder,

you have the main peaks of bismuth oxide,

you have the main peaks of the cement

that can be seen at around 30 - 32 degrees on the X-axis scale,

the bismuth oxide which can be seen at the 27 X-axis scale.

When the powder is hydrated after 28 days,

you can see a new peak of calcium hydroxide,

which is viewed at 18 degrees, two-theta.

This is the typical peak showing that this material

has hydrated and this calcium hydroxide has been formed.

The other peaks which show reduction in the level,

showing material reaction, and obviously,

reduction in the peaks will be shown

since there will be a phase change.

The difference between the Portland cement

and the tricalcium silicate is

that the tricalcium silicate is mostly 99.9% pure,

while the Portland cement has other phases

and it will be only 68% of tricalcium silicate,

which is the reactive component.

When the material reacts,

you get the formation of the calcium hydroxide

and an amorphous matrix of calcium silicate hydrate.

The main uses of this material is for root-end filling,

repair of root perforations,

which can be surgical and non-surgical,

apical plug in apexification procedures, regenerative endodontics,

pulp capping, and as a root canal sealer.

For all material types, we have

the main composition is always

a cement, radiopacifier, and a mixing liquid.

For the new generation materials,

the mixing liquid can be absent,

which means that we have pre-mixed materials.

The normal mixing liquid, which is water,

but sometimes mixing liquids are placed

with various resin types mostly for use as sealers

and for pulp-capping materials.

Again, with the second generation materials,

we have a number of additives which we will be discussing,

because these additives will

enhance the material properties.

In this lecture, we will be discussing

the main material composition,

the properties, and also the modifications.

We will be discussing modifications in the cement type,

the modifications in the radiopacifier type,

modifications in the mixing liquid,

and also the effect of the additives.

The main modification in the cement

is the use of pure tricalcium silicate

instead of the Portland cement type.

Pure Portland cements, since they are made from natural raw materials,

have inclusions of arsenic, lead, and chromium.

All these trace minerals can be found

in the cements as acid-extractable trace elements,

and also in the material that is leached.

And obviously, when it is leached,

it will be leached to the human tissues.

This has raised some concerns,

and the manufacturers have replaced the Portland cement

with a pure tricalcium silicate,

which is made from controlled materials in the labs.

The main problem with the Portland cement is that

the Portland cement, besides containing tricalcium silicate,

also contains another phase.

This other phase is the tricalcium aluminate phase,

which when it reacts, you will have an aluminium phase

present in close contact with the tissues.

This is problematic because as recent study carried out

on test animals has shown that this aluminium phase

can leach aluminium to plasma and liver of test animals.

Aluminium has been linked with Alzheimer's disease.

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