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

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 Provisional Restorations

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

mimic the natural tooth color Available only in one shade 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

2- Adjustment: 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.

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 Fabricating Custom Made Provisional

1- Direct 2- indirect

Direct Made directly inside the patient’s mouth

Indirect: Made outside the patient’s mouth

Custom made provisional Steps for fabricating Custom 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

Direct Faster Fewer steps Slightly inferior in marginal fit 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

Indirect Takes more time Has more steps Better marginal fit 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

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: Most esthetic Accurate fit Brittle Adv. Most esthetic Accurate fit Dis. Brittle subject to bulk fracture