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PROVISIONAL

RESTORATIONSRESTORATIONS

• Provisional crown or fixed partial denture is a

restoration applied to the prepared tooth

temporarily to protect it and to keep the

patient comfortable during fabrication of the

permanent restoration. It influences the

ultimate success of the final restoration. The ultimate success of the final restoration. The

word provisional means established for the

time being, pending a permanent

arrangement (temporary)

Functions of provisional restoration : -

�- Protection

�- Positional stability

�- Esthetics�- Esthetics

�- Mastication

�-Protection :-

The provisional restoration protects the pulp, the periodontiumand the prepared tooth.

It protects the pulp from thermal and chemical irritation caused by foods, drinks and dental plaque.

It protects the peridontium from injury by food impaction due to loss of contact and gingival recession due to loss of to loss of contact and gingival recession due to loss of normal buccal and lingual contours.

Protects the integrity of the prepared tooth from fracture or abrasion due to chewing of hard food on unprotected preparation margins. This is particularly true with partial coverage designs in which the margin of the preparation is close to the occlusal surface and could be damaged during chewing.

�-Positional stability: -

• To maintain the tooth position and prevent

mesial, distal drift or over eruption which will

change the relation with the surrounding

teeth. teeth.

• To maintain the gingival tissue contour,

prevent gingival hyperplasia or gingival

recession.

"-Mastication:

• To maintain the function of the prepared teeth

and enables the patient to use them in

mastication satisfactorily.

••

$-Esthetic:-

• To restore and maintain esthetic especially in

the visible edentulous areas.

Ideal requirements:-

• An optimum provisional restoration must

satisfy many interrelated factors which can be

classified as biological, mechanical and

esthetic requirementsesthetic requirements

I -Biological requirements :-

�- Pulp Protection

�- Periodontal health

#-Tooth position.

%-Tooth Protection against fracture.%-Tooth Protection against fracture.

PROVISIONAL RESTORATIONS

• REQUIREMENTS

• Biological

– PULPAL PROTECTION

• Thermal changes or

agressionagression

• Microleakage

– POSITIONAL STABILITY

• Extrusion or lateral drifting

– OCCLUSAL FUNCTION

• Patient comfort

• Muskuloskeletal stability

PROVISIONAL RESTORATIONSPROVISIONAL RESTORATIONS

• REQUIREMENTS

• CLEANSABLE

– Maintain gingival health

– MARGINAL INTEGRITY– MARGINAL INTEGRITY

• Not impinging gingival

tissue �

– Tissue proliferation

– Recession

– Hemorrhage

• Vertical or Horizontal overhanging margin

II- Mechanical requirements :

&-The restoration should be strong enough to

withstand occlusal forces without fracture.

'-It should be retentive to avoid displacement

#- Easy removal for reuse without being #- Easy removal for reuse without being

damaged

III- Esthetic requirements :

The restorations especially those for anterior

teeth should have

&-Natural tooth color and contour.

'-Natural translucency '-Natural translucency

#-Colour stability

Materials and procedures :-

Ideal requirements of Provisional restoration materials:

�-Ease of handling, adequate working time, easy moldability

and rapid setting time.

�-Biocompatibility – non toxic, non allergic, non exothermic.

�-Dimensional stability during solidification.�-Dimensional stability during solidification.

�-Ease of contouring and polishing.

)-Adequate strength and abrasion resistance.

+-Good appearance, color control and color stable.

--Ease of adding to repair or correct.

.-Chemical compatibility with provisional luting cements.

Available materials: -

The materials can be divided into four resin groups

&. Polymethyl methacrylate ( Jet , Duralay )

'. Poly (ethyl, vinyl or isopropyl) methacrylate.

(Unifast L.c, Trim, Snap) (Unifast L.c, Trim, Snap)

٣. Microfilled composite resin (Protemp).

%. Light cured microfilled urethane

dimethacrylate (Triade)

The light cured materials have two

advantages:-

&-The ingredients are mixed by the manufacture

so show little porosity.so show little porosity.

'-Working time is unlimited.

Single provisional crown may be

custom made or preformed

Resin Cellulose acetate

Polycarbonate

Metal Aluminum (anatomic)

Aluminum shell

Tin silver (anatomic)

Nickel – chromium (anatomic)

• These preformed crown forms are

commercially available; they can not satisfy

the requirement of a provisional restoration,

so they must be lined with autopolymerizing so they must be lined with autopolymerizing

resin. They are available in a variety of tooth

types and sizes.

PROVISIONAL RESTORATIONS

• TYPES

– PREFABRICATED (crowns)

• Aluminum cylinders

• Anatomical metal crown forms

• Clear celluloid shells

• Tooth coloured polycarbonate • Tooth coloured polycarbonate crown forms

– CUSTOM (crowns or fixed

partial dentures)

• Material (variety of resins)

• Technique (direct or indirect)

�-Polycarbonate crown:

• Suitable for anterior teeth as it is constructed

from a color stable resin, but available in only

one shade, this can be modified to a limited

extent by the shade of the lining resin. They extent by the shade of the lining resin. They

are supplied in incisor, canine and premolar

tooth type.

•

Steps:-

*Measure the mesiodistal width of the crown using the mold

guide provided with the kit and select the shell having the

same width or slightly larger width, and place it on the

prepared tooth.

*Mark the crown height on the shell which is equal to the

incisocervical height required for the completed crown using a incisocervical height required for the completed crown using a

pencil.

*The excess gingival length is trimmed away with an acrylic bur

following the curvature of the prepared cavosurface margin.

*Try the shortened shell on the prepared tooth and adjust it if

required until it becomes properly positioned without forceful

gingival contact.

*Apply a uniform thin coat of petrolatum to the prepared tooth

and adjacent tissues (or on the fast set plaster cast)

*Mix the auto polymerizing resin with the proper shade, fill the

shell and place it over the prepared tooth using the adjacent

teeth as a guide for complete seating.

*Immediately remove any marginal excess and when the rubbery

stage is of polymerization reached ( after ' min ) rock the stage is of polymerization reached ( after ' min ) rock the

crown faciolingually to loosen it then remove it to avoid its

difficult removal if complete polymerization taken place in the

mouth .

*Put it in warm water to polymerize (8 min) then adjust the

margins, contour it if required, adjust the occlusion and polish

it to be ready for cementation.

�-Cellulose acetate:

* Available for all teeth types and sizes

*Made from thin (9.'-9.#) transparent shell.

* Provide mold to form P.R.

*Does not bond chemically or mechanically to the resin.

* The shade depends on the lining resin.* The shade depends on the lining resin.

*After the polymerization the crown is peeled off

*Usually need addition to reestablishing the proximal contact

*Less esthetic than poly carbonate crown

*It is less expensive

Steps

• The crown form is selected and adjusted as

polycarbonate crown but the margin can be

cut with scissors.

• Fill the crown with resin as described before, • Fill the crown with resin as described before,

but there is no bond between then so it should

be removed from the set material and the

contact area need addition after that to get

proper contact.

"-Aluminum / crowns and Tin-

silver: -Suitable for posterior teeth Aluminum crown may be

anatomically shaped or non anatomical shells resembling tin

cans which are the least expensive form, but they require

modification and lining with acrylic resin to achieve

acceptable fit, good occlusal and axial surfaces .They areacceptable fit, good occlusal and axial surfaces .They are

fabricated from soft material, this softening cause rapid wear

of the crown, So used as a temporary coverage for short time

only.

Steps:-

*Measure the mesiodistal width of the crown

space and select a suitable shell.

*Measure the occlusocervical height and trim

the shell cervically using a pair of scissors. the shell cervically using a pair of scissors.

Sharp edges left by the cutting should be

smothered with green stone.

*Put the trimmed shell over the prepared tooth,

if any gingival blanches is observed, the shell

should be trimmed further.

• *After marginal adjustment, ask the patient to

occlude, the soft aluminum will deform until

normal intercuspation is reached. Contouring

pliers can be used to make small size

modifications.modifications.

• *Apply petroleum to the prepared tooth and

adjacent tissues, mix self cure resin and fill the

shell when it reaches the correct stage.

*Put the shell over the tooth, instruct the patient to

close and immediately remove the marginal excess.

*Remove it from the mouth at the rubber stage (after '

min) loosen the crown and remove it. Allow it to

completely polymerize in warm water then finish the

margins, adjust the occlusion and polish it.margins, adjust the occlusion and polish it.

*If the contact area is deficient, resin can be added to

correct it after grinding of metal in the contact area

to allow resin to resin bond.

*Polish, clean and cement the restoration.

$-Nickel-chromium crowns: -

Used mainly for deciduous teeth without lining

with resin. They are trimmed and adapted

with contouring pliers and cemented with high

strength cement. They are longer-term strength cement. They are longer-term

provisional restoration due to their hardness.

Custom made provisional single crown:

May be constructed by

Indirect

oror

direct

method using resin material.

I- Custom made indirect

provisional restoration :

• In this technique the provisional is constructed

outside the mouth so it has the following advantages

over the direct technique:

&-There is no contact of free monomer with the &-There is no contact of free monomer with the

prepared tooth or gingiva, which might cause tissue

damage, allergic reaction or sensitization.

'-The prepared tooth is not subjected to heat created

from the exothermic reaction of resin which might

cause irreversible pulp damage.

# The marginal fit of indirectly constructed provisional

is better due to its complete polymerization

undisturbed on the stone cast, while the direct

construction necessitate the removal of the

restoration from the mouth while it is in the rubber

stage before complete polymerization to avoid its

locking into the undercuts. Polymerization outside locking into the undercuts. Polymerization outside

the mouth without a supporting form will result in

distortion and improper fit..

%-The indirect technique reduced the chair time and can

be carried out by a well trained assistant; this

minimizes the disturuption in the office schedule and

earns the patient’s appreciation.

Steps:

*The study cast is constructed from alginate impression before

preparation.

*If the tooth or teeth to be restored has any obvious defect, it

should be corrected on the study cast with red utility wax.

* Fill all the embrasures with wax or putty to eliminate

undercuts.

*Construct the rubber base index for the tooth to be prepared or *Construct the rubber base index for the tooth to be prepared or

the index may be constructed from the patient mouth if the

tooth or teeth are intact.

*Upon completion of the preparations, make alginate

impression for them and pour it in fast-setting plaster.

* After setting, trim the cast so that it includes only one tooth

on either side of the prepared tooth.

*Try-in the index to verify its fit on the fast setting stone cast,

coat the cast with separating medium.

* Mix the temporary acrylic resin in a dappen dish and put some

on the protected areas of the cast, such as interproximal

spaces and in grooves and boxes.

*As the resin begins to lose its surface gloss and become slightly

dull, fill the index, place it over the cast and wrap rubber dull, fill the index, place it over the cast and wrap rubber

bands around them, taking care of proper alignment.

*Excessive force can over seat the cast resulting in provisional

restoration with thin occlusal surface. Also uneven force can

torque the cast to any side resulting in deficient provisional

restoration.

Put them in pressure pot if available or warm water to

accelerate polymerization (hot water causes boiling

of the monomer porosity).

*The restoration is then removed from the cast, if it is

not easily removed from the cast; break the cast with

a heavy laboratory knife.

*The provisional restoration is then finished using

acrylic burs, sand paper discs with different grits.

Finally the restoration is polished with pumice, rag

wheel and rubber cups to be ready for cementation.

II- Custom made direct provisional

restoration :

The rubber index filled with the acrylic resin is seated on

the prepared teeth directly in the patient’s mouth, so

this technique has significant disadvantages as:

*potential tissue trauma from the big amount of

polymerizing resin (pulp, gingiva)

*Poor marginal fit.

Therefore, the routine use of directly formed

provisional restoration is not recommended

FABRICATING PUTTY MATRIX

FABRICATING PROVISIONAL

FABRICATING PROVISIONAL

FABRICATING PROVISIONAL

FABRICATING PROVISIONAL

FABRICATING PROVISIONAL

FABRICATING PROVISIONAL

FABRICATING PROVISIONAL

FABRICATING PROVISIONAL

FABRICATING PROVISIONAL

Cementation :

• The primary function of provisional luting

agent is to provide a seal, preventing marginal

leakage and pulp irritation. The luting agent

should not provide retention and resistance should not provide retention and resistance

against occlusal and lateral forces because it is

of low strength

Ideal properties of provisional

luting agent.

&- Provide seal against leakage and oral fluid.

'- Of adequate strength.

#- Low solubility.

%- Chemical compatibility with provisional polymer.

8 -Ease of manipulation.8 -Ease of manipulation.

=- Adequate working time and short setting time.

>- Compatibility with definitive luting agent and has an

obtunding effect on the pulp.

?- Ease of removal of excess.

Procedures :-

• Lubricate the external surface of the restoration with

petrolatum to facilitate removal of excess cement.

• Mix the two pasts and apply a small quantity just

occlusal to the cavosurface margins avoid filling the

crown with cement because it will provide hydraulic crown with cement because it will provide hydraulic

pressure and will force excess material in the sulcus.

• Seat the restoration and allow the cement to set

them remove the excess from the gingival crevice

with an explorer and from interproximal spaces by

dental floss.

Thank youThank you