Tricalcium Silicate cements as pulp protection materials Flashcards
What are the tricalcium silicate cements?
a group of materials based on calcium silicate chemistry
related to MTA (mineral trioxide aggregate)
What are the calcium silicates related to?
MTA
mineral trioxide aggregate
How does MTA interact with tissue?
bioactive/biocompatible
kind to tissues
placed in direct contact with living tissues
better healing
What is the problem with original MTA?
take a long time to set
new materials have been developed to protect the dental pulp
What are types of MTA?
1) ProRoot MTA (gry or white)
2) MTA-angelus
3) Neo MTA plus
4) TheraCal LC (light cure) - controversial
5) Bio-aggregate
6) biodentine (septodont)
7) tri-calcium phosphate
What material is the focus of this lecture?
biodentine (septodont)
What has allowed the increased rate of the biodentine? (MTA)
particle size so distribution is optimised
What has been added to biodentine to optimise its reaction rate?
calcium carbonate and calcium chloride
What are the 2 basic components of the biodentine?
liquid and a powder
What is the main core material of the powder?
tricalcium silicate
What is the second core material of the powder?
dicalcium silicate
What are the fillers of the powder component?
calcium carbonate and calcium oxide
What contributes to the shade of biodentine?
iron oxide
What contributes to the radiopacity?
zirconium dioxide
What does the liquid part of biodentine contain?
hydrosoluble polymer water reducing agent
superplasticising agent - reduces water content of mixture while helping to retain its workability - surfactant effect
What is the accelerator in the liquid part biodentine?
calcium chloride
Why is biodentine called an hydraulic cement?
due to the hydration reaction between
How is the hydrogel created?
calcium silicates partially dissolve in liquid
produce hydrogel of hydrated silicate
What happens to the biodentine over time?
decrease in material porosity and an increase in its compressive strength over time
What is the setting material of biodentine like?
has hydrating tricalcium silicate cement grains surrounded by a matrix of calcium silicate hydrate, calcium hydroxide and calcium carbonate
What does calcium carbonate act as in the setting material?
acts as a nucleating site on which calcium silicate hydrates - responsible for high calcium ion release
What are the physical properties of biodentine?
similar compressive strength and hardness than dentine
similar flexural modulus as dentine
high dimensional stability (don’t have to worry about expansion and contraction etc)
low fluid uptake and sorption
high washout
doesn’t discolour
What is biodentine designed to be placed on?
both on dentine and vital pulp tissue
What does it mean hat biodentine is bioactive?
induces pulpal cell proliferation and cytokine release
hard tissue formed with an interface synthesised with dentine via a dynamic mineral interaction zone similar to hydroxyapatite composition
plugs of the mineral have been observed in dentinal tubules
kind to living tissues (biocompatable)
What is the dynamic interaction zone?
zone of a mineral layer, where material is interacting with the dentine and a hard tissue forming
what is the pH of septodont and what does it promote?
8.2 - promotes inflammatory cell recruitment and therefore healing
Does septodont allow a good seal?
yes, better microleakage resistance
Is septodont good at marginal restoration?
yes
Can septodont bond to infected dentine?
no, but it can bond to affected dentine
When would you use biodentine?
deep cavities - describes as a dentine substitute
reversible pulpitis - can be left as a dressing and then smoothed down for subsequent restoration
carious iatrogenic exposure
trauma - aim to protect pulp and let it repair itself
pulpotomy in primary molars
Why is biodentine better than calcium hydroxide?
maintaining long-term pulp vitality after indirect and direct pulp-capping
less pulpal inflammatory response and more predictable hard dentine bridge formation
What is the working time of septodont?
6 mins
How long do you leave for the septodont to set?
12 mins from start of mix
What are 2 ways to use septodont clinically?
leave as a dressing and then smoothed down for subsequent restoration
cover with resin composite or dental amalgam
Do you etch with phosphoric acid?
no, use selective etch
reacts - acid/base reaction
What are other products available?
NRC
TheraCal LC
What does NRC incorporate?
HEMA
What is NRC similar to?
white MTA
compressive strength and ph similar
What is the problem with TheraCal LC?
resin itself did not chemically react with cement powder
it remains unchanged with the composite
you get no leaching of calcium hydroxide
it doesn’t work
