Physical Properties required for Good Cement:1. biocompatible

should be harmless to the pulp2. should have adhesive property

should be maintained in tooth tissue3. durability

strong enough to withstand pressures of mastication4. dimensionally stable

no shrinkage/expansion which will lead to secondary caries formation

5. low coefficient of thermal expansion resistant to hot/cold foods, otherwise, if the patient eats

hot foods, the cement will undergo shrinkage; if the patient eats cold foods, the cement will imbide/expand.

6. easy manipulation7. sufficient strength to adhere to other restorative materials8. aesthetic suitability

for permanent restorative materials, should be translucent!

*Depth of CavitiesClass A – 0.2-0.5 mm beyond DEJ ------------ needs CAVITY

VARNISHClass B – greater than 0.5mm beyond DEJ--- needs LINERClass C – deep, but still has substantial dentin needs BASEClass D – has pinpoint pulp involvement ----- needs PULP

CAPPING AGENT

CEMENTS:[non-tooth-colored]

I. Zinc Phosphate Cement “oldest cementing medium”

Components:o Powder

Zinc oxide 90% (main component)

Magnesium Oxide modifier Bismuth modifier

o Liquid Phosphoric acid main

component; strong acid Aluminum phosphate buffer Magnesium Phosphate buffer Water controls ionization of

liquid partially controls setting time (how?)

-gain H20- faster setting - lose H20- slower setting (lose H20 by evaporation)

Dispensing form: powder liquid Manipulation

o Materials: Glass Slab and cement spatulao Ratio: 1.4 gm powder per 0.5 ml liquido Divide the powder into 6 small increments

and mix into the liquid one by one (15-20 sec per increment)

o Sets in 5-9 minuteso DO NOT add another drop of liquid

during mixing!

Why? : The current mix is already undergoing setting!

( so discard it and make a new one)

this is applicable to all cements!

o needs wide area of mixing to DISSIPATE HEAT

o Check consistency Thick and creamy

when the spatula is tapped onto the mix, it should be able to make a thin strand of 1 ½ inch without breakingo Has better cementing

action Thick and doughy when

the spatula collects the mix, the glass slab should be clean.o stronger

Useso Cementing Medium thick and

creamy (thin)o Base thick and doughy (thick);

Class C cavity Physical Properties

o pH 3.5 at time of insertion; lasts for 24-48 hours (neutralized by powder component)

o compressive strength 12,000-16,000psi

o tensile strength 700psi Alter setting time

o W/P ratioo Pre-cool mixing apparatus

prolongs setting to have a STRONGER SET and to be LESS SOLUBLE

II. Copper Cement a.k.a modified Zinc Phosphate cement seldom used; more acidic than Zinc

Phosphate (because of copper salts) same powder-liquid components, but has:

o Copper oxide anti bactericidal Uses

o Temporary restorative material Types:

o Type I 25% Copper oxide 65% Zn oxide 25% Copper oxide 10% Mg oxide pH 0.8

o Type II 2-5% Copper oxide 85-88% Zn oxide 2-5% Copper oxide 10% Mg oxide pH 2.5

o after 28 days, Type I & II’s pH becomes pH 5.3

(still acidic because of copper salts)

III. Zinc Oxide Eugenol (ZOE) “most versatile cement” pH 7

Components:o Powder

Zinc oxideo Liquid

Eugenol Dispensing form

o 2 paste formo powder-liquid

ADA Classification Accdg. To Usage:Additional components

Compstrength

Tensile strength

manipulation

Uses

Type I Conventional ZOE

-- 800-1200 psi

200psi Powder-liquid- Thick and creamy2 paste – 1:1 homogenous color

*temporary cementing medium*Obtundent material in RC therapy

Type II EBA-Allumina ZOE

Ethoxybenzoic acid

Alumina

9320 psi 1030psi Thick and creamy

*permanent cementing medium

Type III Polymer Modified

Polymethyl methacrylate

7308 psi 603 psi *powder is heavily coated1 scoop, 1 drop Thick and doughy

*Temp. Restoration*Base

Type IV ZOE Liner

-- 798 psi 62.3psi 2 paste form-1:1 homogenous color

*liner (on areas not on direct masticatory forces)

* Non-eugenol Zinc oxide

-- -- -- -- *impressions

Check consistencyo Thick & doughy be able to roll mix

into rope-like How to prolong storage life of Liquid

o Use plastic container that doubles as dropper

o Use amber-colored bottles* not compatible to resin restoration!

eugenol will alter polymerization of resin!

IV. Zinc Polycarboxylate/ Zinc Polyacrylate Very acidic, but kind to the Pulp

Components:o Powder

Zinc oxide main component; opaque color

Magnesium oxide modifier Calcium hydroxide modifier Flouride anti cariogenic agent

can remineralize demineralized enamel (as long as there aren’t any cavities yet)

o Liquid aqueous solution of polyacrylic

acid very big molecules,

can’t pass through open dentinal tubules (that’s why it’s biocompatible)

50% by weight WATER + Co-polymer

Chelation Processo Chemical bonding to tooth tissueo Bonding of the free carboxyl group

of polyacrylic acid liquid and Calcium ions of enamel and dentin The mix should be readily packed

after mixing!o Why?

To allow chelation process to occur ( diba sa FREE carboxyl group lang nagbbond yung enamel and dentin? :D pag pinatagal mo pa yun, wala nang bond na mangyayari! :D)

Shiny surface- pack it while it looks like this!

Dull surface- indicates initial setting (can’t pack on this state anymore)

Dispensing formo powder-liquido single powder component

just add water (haha!) why is it possible?

Liquid component has been freeze-dried

(complete dehydration) Manipulation

o Materials: Glass Slab and cement spatula

o Divide the powder into 2-3 large increments and mix into the liquid one by one ( for a slower set!)

Mixing time: 45-60 seco Sets in 4-5 minuteso Check consistency

Thick and creamy thin strand (1 ½ inch w/o breaking)

Thick and doughy when the spatula collects the mix, the glass slab should be clean.

o stronger Uses

o Luting Agent thick and creamy (thin)

don’t need varnish!-why?

-*this blocks enamel and dentin walls, thus, chelation isn’t possible anymore!o Base thick and doughy (thick);

Class C cavity Physical Properties

o pH 1.7 but biocompatible since it’s molecules are very big to fit into dentinal tubules

o compressive strength 8000psio tensile strength 1030-2250psi

more inferior strength than Zinc Phosphate, but more preferred because of it’s chemical bonding

o biocompatible if >1mm of dentin is left, but, if <1mm of dentin is left

(pinkish dentin), use a pulp capping agent before using Zinc Polycarboxylate ( din a sya ganun ka biocompatible pag may pulp nang kasama)

V. Calcium Hydroxide Ca(OH)2

Dispensing formo single powder component – just add

water! :Do 2 paste – (base & catalyst)

Components: 6% Zinc oxide 6% Calcium Hydroxide suspended in chloroform solution

of resinous material common solvent: aqueous

methyl cellulose volatile substance! If this evaporates, the mix

will set. Responsible for the very

short setting time ( not even 30 sec!)

o single paste – light-curing system; light activated

developed to compensate for very fast setting time of 2 paste form

before: uses UV light (but causes skin irritations)

now: uses Halogen light ( safer! Can cure thicker cement)

Manipulationo For paste forms:

Use: ball tip spatula & mixing pad

Mix till homogenous color Uses

o Pulp capping agent directo Liner Class B cavity

Physical Propertieso pH 11.5-13 biocompatibleo compressive strength <1200psi

♫ Cavity Varnisho Components:

Natural gum- copal, rosin, synthetic resin

Organic solvent – acetone, ether, chloroform

just like nail polish! :D

o Uses Prevents galvanism

By sealing open dentinal tubules

Prevents discoloration under amalgam restoration

If none, the dentin might be gray-ish due to amalgam

Prevents marginal leakage under amalgam restoration

Prevents chemical irritation from acidic cement

By sealing open dentinal tubules

Cavity liner Upon double application

o How to apply? Paint with camel hair brush (most

preferable!) Use a pellet of cotton Wire loop

* not applicable to resin restoration varnish alters proper polymerization