Provisional Restorations

Dr. Arwa H.AL-Musa

211 RDS

Definition

A dental prosthesis worn following the tooth preparation for a various periods of time, which maintains esthetics, provides articulating surfaces & protects hard & soft tissues prior the delivery of the permanent dental prosthesis (temporary, interim)

Requirements

1- Protect the remaining tooth structure from chemical, thermal & biological insult.

2- Pulpal protection: a- Thermal insulation b- Well adapted margins to prevent leakage of saliva

3- provide for esthetics, phonetics and masticatory function

4- Maintain the health of the periodontium, should have no overhangs or impinging margins

5- Diagnosis and patient evaluation.

Types of Provisional Restorations

1- Zinc oxide eugenol (IRM).2- Prefabricated provisional restorations.3- Custom made provisional restorations.

Zinc oxide Eugenol

Zinc oxide eugenol (IRM) :

Polymer-reinforced zinc oxide eugenol interim restorative material used for small intracoronal preparations e.g. inlays

Disadvantages:

a- doesn’t protect the remaining tooth structure b- can only be used as an intracoronal restoration

Prefabricated ProvisionalRestorations

Definition: ready-made restoration that needs minimal adjustment

e.g polycarbonate crowns, metal crowns

Polycarbonate Crowns

Tooth colored, supplied in incisor, canine and premolar shapes

Adv.

• mimic the natural tooth color

Dis.

• Available only in one shade

Prefabricated Metal Crowns

• Suitable for posterior teeth

• Needs some modifications for

proper adaptation

Steps of fabrication

1- after tooth preparation, select the proper crown size from the mold

A- polycarbonate crown:

adjust the length of the crown by trimming the excess gingival part using carborundum stone or acrylic bur

2- Adjustment:

A- Metal crown:

length is adjusted by removing gingival excess by scissors, then smoothened and contoured using plires.

2- Adjustment:

3- apply separating medium on the prepared tooth ( petroleum jelly)

4- mix autopolymerizing acrylic resin in a dappen dish

5- Fill the crown with acrylic resin then seat it correctly on the tooth and remove the excess resin around the margins.

6- check the occlusion using articulating paper

7- remove the high spots then finish it and polish it using white stone burs and rubber points.

8- cement it using temporary cement.

Custom Made Provisional

Made to fit specifically the patient’s prepared tooth

Techniques for FabricatingCustom Made Provisional

1- Direct

2- indirect

Made directly inside the patient’s mouth

Direct

Made outside the patient’s mouth

Indirect:

Steps for fabricatingCustom made provisional

1- Direct technique

1- Take a preoperative impression ( before the tooth preparation).

2- After tooth preparation, apply a light film of petroleum jelly ( separating medium).

3- Mix the self-cure acrylic resin in a dappen dish.

4- Fill the impression at the area of the prepared tooth with acrylic resin.

5- Place the impression on the prepared tooth correctly.

6- Take it in and out until the material sets.

7- Remove the provisional rest.

8- Then finish it and polish it.

9- Check the occlusion then cement it using temporary cement e.g. temp bond cement.

Wake Up!!

1- Indirect technique

1- Take a preoperative impression.

2- After tooth preparation take a postoperative impression and pour it to get a postoperative cast.

3- Apply a separating medium on the cast then mix some acrylic resin in a dappen dish.

4- Fill the preoperative impression at the area of the prepared tooth with acrylic resin.

5- Seat the postoperative cast into the preoperative impression.

6- After the resin has set remove the provisional and finish it an polish it.

7- After the resin has set remove the provisional and finish it an polish it.

8- Try it in the patient mouth and check the occlusion

9- Cement it using temporary cement material.

It’s almost over

Adv.

• Faster• Fewer steps

Dis.• Slightly inferior in

marginal fit• Might lock in the

undercuts of the prepared tooth

• Thermal &chemical insult to the tooth

Direct

Adv.

• Better marginal fit• Avoids the possibility of

locking on the tooth• No thermal or chemical

insult to the tooth or soft tissue

Dis.

• Takes more time• Has more steps

Indirect

Materials Used for custom made provisional restorations

1- polymethyl methacrylate

Adv.

• High strength• color stability• wear resistance

Dis.• Tissue damage

from the monomer & exothermic heat reaction

• Polymerization shrinkage

2- polyethyl methacrylate

Adv.

•Less exothermic heat reaction•Less polymerization shrinkage

Dis.

• Less color stability• Less wear

resistance

3- Filled Resins:

Adv.

• Most esthetic• Accurate fit

Dis.

• Brittle• subject to bulk

fracture