DM Sheet #6 By Mutahar Hanash

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DM Sheet #6 By Mutahar Hanash

Post by Sura on 9/11/2011, 12:09 am



Last edited by Sura on 9/11/2011, 3:04 am; edited 1 time in total
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Sura

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تاريخ التسجيل : 2010-09-29

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Re: DM Sheet #6 By Mutahar Hanash

Post by Shadi Jarrar on 9/11/2011, 3:03 am

At the beginning Thana ’a talked about capillary attraction which is the ability of a liquid to flow against gravity where liquid spontaneously rises in a narrow space such as a thin tube, or in porous materials such as paper or in some non-porous materials such as liquefied carbon fiber.

Last time we talked about direct restorative material, today we are going to talk about indirect R M which includes:

Ceramic, metal {alloy (precious+non precious)}, polymeric type of material could be (indirect composite +fiber reinforced composite temporary acrylic material)

Generation 1+2 is very premature wma est5dm-nahom mzbo6

3rd generation: etching with strong acid (phosphoric acid) &bonding agent without primer.

4th generation: etching with strong acid, primer, bonding agent. This is the most reliable bonding.

5th generation: etching& (primer and bonding agent) together.

6th generation: self-etch primer (primer with weak acid) +separate bonding agent.

7th generation: all in one (self-etching adhesive).

2nd Q) why we make two to four pours mno!!!!!!?Bdna separate m3a enno hath bonding agent. (Sorry ya jma3h 7ta Ana msh fahem!! :(

Bonding agent that we do apply more than one,,, el2shya elly kna nst5dmha primer then we put bonding agent so we get 2 layer, now we want to make these in one step, but the problem we need to evaporate the solvent, to evaporate the solvent u need to thin it we put air spray, when u thin it u leave a layer less than 5 micron to reach hybrid layer and resin tag.

As u remember we took something called (oxygen inhibiting zone).now when we make composite we add it layer by layer, 6yb keef el 1st layer adhere to the 2nd layer? 3omary said that, super facial layer which is in contact with oxygen ma by9eer elha cure; allow us to put another layer. Actually at least 5 micron not undergo curing fa we put another layer on them. The same analogue does apply to the self-etch adhesive we have to put another layer 7ta el2wla y9eer elha full curing. There was a Q by student (sorry I couldn’t hear it well L) Dr said msh da2mn,now they try to overcome this problem coz our target in all in one technique eno n3ml one layer, one application leesh nrj3 n76 more application. Now bel new type they try to overcome this problem by another mechanism .hla now e7na we need to apply more than one layer, but new type 2011 (new recent) or some company said eno one layer is enough (dent apply )!!! Independent dental research.

Q3) what’s the ideal requirement for bonding?

Why we can’t use mild type of self-adhesive on the outer surface of enamel or sclerotic dentine? Coz we try to,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, but

In enamel we can use normal acid etch (phosphoric acid) then high self-etching adhesive. (We have gel that we use, applied with syringe (large page syringe with small tip, don’t use brush. (fy mt9l m3na men el-brazil)

M Abukar asked about Effect of repeated cyclic loadings.Dr said most of company said enno we get good bonding with self etch adhesive .But the problem with self etch adhesive as Thana ’a said (capillary attraction),,,,,,,,,,,,, da2mn by9eer fy ,,,,,sticky monomer below residual part (lets us nsmyhm high surface energy this molecule react with water every time react with water it undergo plasticization (u heard this in acrylic +soft relining material ). EL material bt8sa m3 el water, every material must has elastic recoil whatever the force so el material won’t broke unless plasticization occur coz el material can’t tolerate, this what we called repeated cyclic fatigue. Now there is smart molecule trying to go into chemical bonding b6lna ns2l 3n el micromechanical retention,el chemical bonding will not affect by plasticization of material.

Ideal requirement for bonding:

1) High consistent bond strength to enamel and dentin.

2) Easy quick application.

3) Consistent product quality.

4) No postoperative sensitivity.(in case of total etch technique).

5) Universal use with direct and indirect filling.



In direct restoration we make light cure, but indirect R most of time we can’t use light cure, we have to have another mechanism ,elly hy self cure (7ta n3ml self cure with light cure there is something called duality of cement(not sure) and we need 2 initiator (chemical+photoinitiator ) .we can’t use this duality of cement in direct material bcoz it undergo setting then change in color 3shan heek el veneer is translucent most of the time we can’t use duality of cement for it (veneer ), bcoz chemical initiator that we use to get self curing undergo degradation with time+ discoloration.



When we need to bond for all ceramic? As u took in the lab, we prepare almost parallel wall for retention, we mean by retention by passive cement.

What’s the difference btw active and passive cement?

Passive cement just a friction when we put it btw 2 materials it’s difficult to slide them and active eno bn3ml bonding like bonding in composite. There was an article in 1999 (classical article), they make study from 1984 to 1999 for why we need to make bonding.

When we have short clinical crown either high strength ceramic or metal (r7 n7ky 3nhom soon)!!! Lma ykoon 3na weak wall as u see we put fiber post cementation as Dr Foud will talk about them soon. What’s the function of post (especially el metal one)? Someone said it increase strength,Dr said no bel 3ks it decrease the strength, post make retention for core elly r7 y3ml retention for crown. If u have enough four buildup material (a7san 4 material enamel and dentin for crown preparation +post and core), most of time we use minimal preparation for metal restoration.



A picture about veneer: those veneer are silica based ceramic or ……………………ceramic, here we don’t make any preparation just we make impression then send it to the lab .if we put crown 3adi here r7 y79lo debonding or decementaion , bs la2no mbny 3 active bonding we do replace tooth structure, as u remember minimal invasive procedure or biomimetic approach, when we talk about this, this is one of the indication. We just replace what is missing here and we do bonding technique.



Full crown preparation: example, we make zirconia crown ……………………………………………………………………………………..





Ceramic: 7ta n3ml etching on enamel and dentin sho lazem ykoon 3nna?

It must be a friction that we get it by roughness, lma n3ml acid etching we do what we called preferential etching means an area is etched more than the other for example intertubular dentine will affected more than tubular dentin. Same case in ceramic, 7ta ykono etchable lazem ykon fyhom component that is etchable more than the other, 7ta ykon etchable bkon fyhom scattered …… porcelain(there is something called low side (not sure) ,they r more prone to acid etching attack.

Dr mentioned things like glass ceramic, alumina ceramic and laminate ….and he said we will talk about them late.

Always remember we have 2 adherents, one with tooth structure and the other with substrate metal, porcelain or ceramic.

Lma Kona n3ml bonding m3 composite with enamel or dentin sho Kona n3ml m3 el tooth structure? We make acid etching then bonding (priming and bonding) or self-etching technique.

Bel nsbh ll passive(not sure) tooth structure , it’s the same either we make acid etch+ priming& bonding or self etching .The other side of story on ceramic ,we make etching with Hcl with less % either 9 or 10% but for a longer duration most of ceramic we need one minute ( u should follow the manufacture ).

Comparison btw composite and ceramic: we have interface 1 with tooth structure and interface 2 with ceramic and adhesive in between (bel no9) w elly lazm n3ml self-treatment for tooth structure and self-treatment ll metal for porcelain!!

This is the important thing that we talk about.

In case of porcelain or etchable ceramic we use Hcl then saline coupling agent (to make chemical bonding) and to catch silica particle that found in ceramic and porcelain(silica particle in ceramic and silica particle in the filler of porcelain.3shan heek el porcelain laminate veneer is durable for ……(sorry) coz el chemical bonding.

Dr showed us a pic: this is HCL and saline coupling agent; ideally we should have two component saline coupling agent coz of time degradation.

Now lma n3ml HCL ll porcelain or etchable ceramic by9eer in pattern like grossly appearance that we get in enamel, w saline coupling agent it’s better to expose them to heat treatment (to make strong bond) then we make bonding (3shan ma n3ml bonding with the adjacent teeth we need to apply …material elly hy Teflon (tb3 el mowa9eer) to make isolation ll teeth.

في 15 ثانيه والله ماعرفت اسمعهم كوي س انا اسف ياجماعه بس طلعت روحي

7keena 3n el other side eno 3mlna acid etch (acid etch rinse or self-etch technique) now lma n3ml m3 el crown we prefer etch and rinse technique (conventional resin cement) w lma n3ml post we prefer self-adhesive cement coz we can’t apply acid etching then rinse.

Remember this in coming year msh shr6 this year, lma n3ml crown preparation fy what we called immediate dentin bonding!!!!!!!!!!!!!!!!

After we make preparation here in canine we rinse and apply prime and bond (we light cure it) then we put temporary crown then take an impression send it to the lab, after 2 week we make what we called it microgentic(not sure) ll tooth structure (n3ml bond ).

As u remember when we talk (first lecture) about preparation especially (incisor and canine ) we remove 60-70% of tooth structure, this mean ell dentinal tubule b tft7,if we let dentinal tubule opened then put temporary crown there is likelihood eno y9eer pulpal inflammation (maybe reversible pulpitis ) and 10-20% maybe irreversible pulpitis .

Dr mentioned trade name!

A pic showed…………klashinkoof el Gadhafi (hhhhhhhhhhhh)

واخيرا خلصت من ها الشيت

الصوت والله مش واضح الدكتور بيتحرك كثير والصوت بيقطع كمان بس I did my best to write this sheet

Any corrections r welcomed

Done by: Mutahar hanash

Lecture: 6
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Shadi Jarrar
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عدد المساهمات : 997
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تاريخ التسجيل : 2009-08-28
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