Lecture 15, Endodontic materials and bleaching systems I (Script)

8/3/2019 Lecture 15, Endodontic materials and bleaching systems I (Script)

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Endodontics material and bleaching system (1)

Dental Material II

lecture # 15

Today we will talk about material which is used in root canaltreatment of teeth and the material which is used to Whiteningshade of the teeth ..

Slide 2 :

Now endodontics is concerned with everything that has to do withroot canal system whether it physiology, pathology. Treatmentand tissues around the root .. so (Root canal system andperiradicular tissue, tissue in the peri-apical area around root).

Now these dental material used in this source of treatment can beused for removing pulpual tissue, cleaning canal, shaping themand then filling them ..

Like when we drill a cavity in the crown you want to restore it byplacing a restoration to seal it .. so the same does in the root

canal system u clean it then remove infected tissue and then youshape it properly to resive a filling at the end .

So you want to maintain a seal at the apical area at the apex ofthe root and seal coronaly to prevent bacteria from going insideagain and causing recurrent infection .. same principle you wantto prevent micro-leakage, recurrent caries, sensivity ,,,, bla blabla ,,, :P

Same goes for the root canal system you want to clean it and

obdurate it or fill it prevent bacteria to income again and causinginfection all over again.

Slide 3 :

This picture represent the tissue inside the pulp .. This is a lowermolar there are lateral spaces into which pulpal tissue may go, soyou dont just have one single pulpal tissue inside the canal thereare lateral canals irregularities into which the pulpal tissue cango.

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So we need to clean the entire area and fill it to prevent theformation of the remainder of any space into which bacteria cancome in and colonies ..

cleaning w elshaping

.. infection

Slide 4 & 5 :

Before we start RCT

If you remember when we talk about cement we talk about

something called direct and indirect pulp capping. We talkedabout calcium hydroxide that used for this purpose.

Now the pulp might be exposed and need of treatment formany reasons. Maybe expose by caries, it can be exposed dueto trauma (fracture on the tooth) or it can be exposed duringcavity preparation.

There are two procedures to treat the pulp or heal it beforegoing into root canal treatment

(Direct and Indirect pulp capping)

** So in cases of indirect pulp capping: we are leaving a verythin layer of dentine because you know that if you want toremove it because it is stained you will expose the pulp, so youwant to avoid these exposure by leave a layer of disscoloreddentine.

Slide 6 :

This is the 1st picture the dentist is trying to excavate thecaries, then he leave this layer of stained dentine (it is hard butit is stained). So we dont 100% sure that there is no bacteriainside them.

So in order to prevent pulp exposure we place a dressing ontop of this layer, this dressing will be followed by restoration.The aim is to seal the cavity prevent any nutrients or newbacteria from going in, so even if there is still bacteria inside

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this stained layer. If there is no nutrients coming in thesebacteria will be die.

And will be a rest of carious process.

So a layer of this discoloured dentine left a dressing is placedon the top which is mainly carbon hydroxide, its alkaline or ithas a high PH (antibacterial). So it will kill any bacteria there,and will a rest a carious process and on the top we dontreplace a tempering filling we place a Permanent filling, why ?because it is provide a better seal.

Prevent any micro-leakage prevent any more bacteria to go inand causing caries all over again. So this is INDIRECT pulp

capping. The pulp is not expose (Mainly the material which isused the carbon hydroxide, ZOE maybe used).

Due to sedative effect some time we use bonding agent butyou have to remember that when you want to use bondingagent you need to etch 1st. And you are etching or using acidvery close to the pulp, so this may cause many problems. Soyour best choice is Calcium hydroxide. Sometimes mtra bondmaybe use or resin modified glass inomer cement.

Now the idea is to seal off any bacteria or nutrients and stopthem from coming again. So you want to maintain a good seal(calcium hydroxide is good) because it has anti bacterialactivity that is why it is the 1st choice.

If by any chance the pulp is exposed. We need to do ** directpulp capping. If you want to do direct pulp capping yourexposer need to be very small and tiny, no bleeding outside ofthe pulp. So the pulp should not be inflamed, this is not be anysymptom of severe pain.

So pulp was exposed, all around is clean it is not cariousexposer (the exposer did by the dentist during cavitypreparation). So you have cleaned the wall of the cavity andyou want to drill a little bit farther on the floor and a very smallarea of the pulp was exposure.

You dont want go ahead to do root canal treatment you wantto try save the pulp. So you do direct pulp capping now thisarea need to be clean. Or less infected so sometimes we use a

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solution called (sodium hypochlorite) like hapex to clean theexposure area.

If there is no blood coming out no previous symptom withsevere pain, so you will dress the pulp, you want try to heal itclose this exposed area. Best material is Calcium hydroxide. :P

Slide 9 :

So this is an example, this is a fracture tooth due to trauma, sothe incisor was fractured and this fractured involve the pulp(can you see the pink tissue).This is exposed pulp so you dont want to open it up and doRCT. It is an aggressive treatment.

You want to try save it and heal and close this exposed area. Soyou applied calcium hydroxide (a thick layer followed by apermanent restoration) to provide good seal and to prevent anycontamination.

Another material we will learn about it later on. Its called MTA. Similar material it has high PH, it is Anti bacterial and itstimulates dentine formation, so when it stimulates the dentineformation a barrier or a bridge of calcified tissue will form and

close up this expose area. So a dressing is place and then wereview a patient after sometime maybe we can take X-ray, wewill see there is a bridge of calcified.

Slide 11 :

If there is any chance with a patient come back with severepain or swelling that means the inflammation is spread and thetreatment was failed. You have to go on RCT. Pulp capping mayfail because there is a chronic inflammation in the pulp,because the restoration fail and was associated with micro-leakage so there is no good seal around.

Sometimes there is a blood clot formation at the exposed area,so there is no contact between the calcium hydroxide and thepulpal tissue. So because there is no contact there is nostimulation for dentine formation. So the medication doesntreach the wall, so the treatment fail.

So failure direct pulp capping maybe cased By : Restorationfailure and micro-leakage.

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Because there is already chronic inflammation inside the pulp.And there was a clot formation at the exposure area. It willprevented calcium hydroxide from, making contact in thepulpal tissue and inducing dentine formation.

So

1- Already inflammation in the tissue.

2- The restoration is fractured or failed casing micro-leakage.

3- Large exposure associated with large bleeding with clotformation

All of these lead to failed of pulp capping so we need to do

RCT.

Slide 12 :

The 1st step of RCT is we want to gain access to the whole partentire pulpal tissue in the crown. You want to remove the pulpaltissue in the crown and then you want to go ahead and removethe pulpal tissue in the root canal.

Now once you do that you need to wash that area and clean it.For that reason we need to use irrigants (certain solution).These solutions the purpose of them is to disinfection andremove the debris. Now when you drill the cavity in the crownwe use the syringe air and water to clean it and remove thedebris.

We use phosphoric acid to etch and remove the smear layer.Same things in the root you want to irrigate to insert fluid under

pressure to remove any debris and disinfect (remove bacteriaor kill it).

Now this irrigants needs to be non-toxic, non irritants, it shouldbe able to remove debris, smear layer, it should be able to flowall over the surface. So it should have low surface tension, so itshould be able to wet the surface properly and able to sterilizeor disinfect.

These are ideal properties that we want to be available in our

irrigants. Now the irrigants that are available some of theseproperties are available but not all of them.

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Slide 13 :

The most commonly use irrigants are sodium hypochlorite.Some dentist use normal saline.

You want something to disinfect, so sodium hypochlorite (2 _10%). It is usually placed into syringe and then you insert the tipof the syringe inside the orifices of the canal and irrigate.

But this technique is irritants due to hapex. So you should becareful when you use it not to allow it to contact with gingivalor the tongue or the oral cavity. So that is why we need a goodisolation, how ?? By using a rubber dam (green rubber sheet),we place it around the tooth that we are treating.

It will isolate it from the rest of the oral cavity.

There are alternatives materials that can be used but they arenot as good sodium hypochlorite. One of them chlorohexidinelike the mouth wash.

Another material that can be used as a lubricant not irrigant iscalled EDTA. What does lubrication means? When you cleanedthe canal or instruminting inside the canal you are using a file

(you remember the odontodotics file in the metal lecture).Now to ease the use of these file when they go in and out weneed something to lubricate like Vaseline lubricate. One ofthese lubricants is EDTA.

Another uses of these material is when you have a canal that iscalcified very narrow space left). EDTA is able to removecalcium from these calcified canal open them up a little bit, soyou can instrument them easy.

So EDTA is a lubricant, we can use it to move the file easily inand out the canal during instrumentation. And it can also beused to open the calcified or narrow canals because it canextract the calcium (remove it and open up the canal a little bitto get access to the whole surface of the canal).

So EDTA it is a lubricant or a decalcifying agent or a cleathingagent

Slide 14 and 15 :

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Now when we do irrigation we remove the pulp to irrigated thecanals we clean it but we cant fill the canals in the same day.You want to send the patient home and then call him backagain to continue treatment. We cant finish the RCT only in

one session we need two or three.So when we sent patient to the home we should not leave thecanals empty and only put the temporary restoration above it.We should not remove any space inside the tooth. It should befilled. Any leave space it will be a big chance for bacteria to getinside it to colonize inside it.

So you never leave a space inside the patient tooth !!

When you send him home you need to place somethingtemporary inside the canals, such as the temporary filling in thecrown. Now this is temporary material needs to be able to fightbacteria to prevent re-infection of the canal.

Now the best material is again Calcium hydroxide, this calciumhydroxide is non sitting material (it will not set). Why it isimportant the material not to set?

Because you can easily remove it when the patient come back

again. So it is a temporary material so I can place it inside thecanals it can supply it by a syringe with a disposable tip. So weuse one tip for each patient. So place the tip of the syringeinside the canal and inject it, sometime I can use acryl file.

So this material will act as the temporary material and it willhelp to fight infection if there is any remaining tissue which isnot able to remove it this material will kill it.

Now after it is placed we can call the patient again after days or

weeks, we remove it by using irrigants material which is sodiumhydroxide and clean the canals again and go on with apermanent filling.

Some time we use other type of material pasts that containssteroids or antibiotics in them but this material is more useful.

Sometimes if you got young patient where his teeth are stillimmature (means that the Apex of the root is not closed yetlike primary teeth, but this is a permanent teeth but still

developing). The root does not closed yet.

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So it is not easy to obdurate or filled these root canal .. so whatdo we do ?

We can place calcium hydroxide Again to form a barrier acalcified bridge that will close the apex of the root. And then wecan go on our treatment.

So calcium hydroxide can be used in immature teeth with openapex when it place inside it can induce the hard tissueformation to close the apex so we can after that do theobturation.

When we obturation or filling of the canal your doingcondensation we want something hard to condense against.

If the apex is open your material will go out into the peri-apicaltissue, so we want to close up the apex in immature teeth orinduce root formation make it faster so that the apex can closeand you can condense your filling material inside the canal. Sothis is another use of non sitting carbon hydroxide ..

Slide 16 :

Now we want to fill the canal.

Previously they used to use pasts (medicated pasts ). Thatcontain formaldehyde or iodoform. But formaldehyde is a verytoxic material so may case many problems like inflammation,resorbtion ... ect

A iodoform pasts it is a restorable which means it is highsolubility it will not stay there.

They used to use silver cones, the problem is this material isvery hard if there is any chance you want to do retreatment. It

is very hard to remove it outside of the canal and the problemof silver is corrosion. It can also cause staining.

So the more current material which is use nowadays are Guttapercha or Gutta pur(ch)a from American, which is morecommonly.

And polyester resin.

Slide 17 :

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it means they might be small spaces or voids left .. What willthese void seal with ? What can we use ?

We use cement, we use sealers like a pasts. So inside thecanals you will have Gutta percha and a sealer together.

So the major space will be filled with Gutta percha and the verysmall spaces or voids will be filled with cement or with sealer.So we will have complete seal (no bacteria, no space)

slide 20 :

So this is Gutta percha use for core condensation so it is usedwhen it is cold, for thermal packing they called (alpha phaseGutta percha). Alpha phase just refer to its structure. So betaphase gutta percha is the cold one. Slightly different structurefrom the alpha phase Gutta percha which was heated. So Guttapercha maybe softened or heated and then placed inside thecanals.

Now if you softening it they called thermafil system. If youmaking it melted and inject it inside the canal that called thesystem obtura.

slide 21 :So when they melt the gutta percha they load it inside this gunand then inject it with this tip inside the canal or they melt itsoft (this is the Gutta parcha around the file) they place it inthis machine it is a small oven).

This oven will heat it to 60 65 degree until it will soft. So youtake it out and then place it in the canal.

So you either soften the Gutta percha in this oven (thermafilsystem). Or they melt it away (pieces of gutta percha place it inthis gun melt it and then inject it like a paste inside the canal).After that it will cool and become set.

So thermafill system, soften gutta percha, obtura, melted guttapercha.

Slide 22 :

Another filling material it is similar it is called polyester resin. Itis thermoplastic it contains polyester resin; it is contain barium

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sulphate, bioactive glass. This material is able to releasecalcium and phosphate which will promote bone formation.

It is available as cold and thermoplastic material. So similaravailability but the composition is slightly different.

Slide 23

Now sealers that are use to conduct very small spaces lead tohave certain properties:

1-they need to be easy to use.

2-they need to proper's good seal.

3-they need to have low solubility.4-Radiopaque.

5-Biocompatible.

6-long working time to takes time to fill root canal system notlike when you use amalgam and you condense it.

In case in root canal treatment it will take some time especiallyif you working in molar tooth because it have multiple root youneed some time so you need material has long working timeand low setting time relatively.

So these sealers will fill the spaces between the GP and it willalso act as lubricant so that obturation technique or whenobturating the method easy it easy to depth the GP inside thecanal and condense it.

6b3n 2ltechneq of condensing GP will learn about it nextsemester. :P

Slide (24)

Now this the representation or this is the picture of whathappened if you use GP with no sealers can you see the spaceso there is the gap there will be a gap. In this gap in the in leftthis space is available for bacterial to come in and colonize nowif the space it close up it will be close up with sealers so

prevent any infection from occurring again that's why itimportant to use the sealers.

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How it is use usually you mix it like the base and then the GP isdepth in the sealers and then place in the canal.

elsealers hada mtl 2lm3jonh btn5l6 ob3den bnmsk kol GP coinobn3'6ha bhl sealers obn76ha bl8nah 2ltaneh b6re8h mo3enhso GP will be surrounding with sealers and the sealers will helpto contact with surface of dentine inside the canal and it willalso attach the GP coins together so will have good seal allover.

Slide (25)

The material that used as a sealers depended in the basiccompound some of them they based in calcium hydroxide and

some of them based on zinc oxide eugenol or on glass ionomeror on resin.

So same material can be used in different application each onehas advantage and disadvantage for example: calciumhydroxide sealers they have high ph, antibacterial, easy to useand long working time but the problem is there have highsolubility this is a major problem.

Resin cements it has low solubility which is good and if you use

a primer with them to etch the surface it will help to bond themto the dentine.

Glass ionomer sealers their able to chemically bond to dentine,which is good but the problem is when they set they becomevery hard and retreatment very hard it they have to remove itcompletely when you want to do retreatment again and againthe problem with solubility.

Slide 26 :

So zinc oxide eugenol base cement they are many formulationsavailable or product available usually available as paste, pasteyou contaminate the two paste together to get onehomogenous color.

Now examples are: 1- Grossman

2- Rickets

3- Tubliseal

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Each one has different properties usually Grossman has goodflow, low film thickness, use as enough working time 20 minworking time, the solubility is low .

Rickets for example has short working time and thin filmthickness and you once thin film between the dentine and GPwhen you got thin film will get better bond ok.

So it good to have slow or low film thickness of the sealerswhich means that it will flow even better a cement or sealersthat have low film thickness it mean that will flowing very willcovering the inside perper (I think I couldnt hear).

Slide (27)

So this is how it's supply as two paste (base and catalyst) mixtogether.

Slide (28)

Calcium hydroxide again is long working time, antibacterial,biocompatible, the disadvantage is high solubility. So theadvantage and disadvantage are similar everywhere.

Slide (29)This is seal apex.

Slide (30)

Resin sealers which are more commonly used now becausetheir low solubility and long working time one of the famousones are (AH plus) now before AH plus they used product AH26the problem with AH26 it contain formaldehyde which is atocxic

material so they made anewer material with no formaldehydethey call it AH plus so it has low solubility, good flow, longworking time, low film thickness.

Another material it called ADSEAL again by biocomability, lowsolubility.

So in general resin sealers has low solubility.

previous product used to have as I said formaldehyde some ofthem used to have silver silver it is the problem because ofcorrosion and shrinkage. So we can replace it by another

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GooD LUCK ALL

Done by : Sara Alomari & Dalia Shunnaq

Special thanxxx for lovely friends:ruba,waad,arwa.amoon.alaa ..

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Lecture 15, Endodontic materials and bleaching systems I (Script)

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Transcript of Lecture 15, Endodontic materials and bleaching systems I (Script)