Provisional Restoration (Temporary Restoration) PDF

Lec.6 PROVISIONAL RESTORATION (TEMPORARY RESTORATION) Its important that the prepared tooth or teeth be protected and that the patient is kept comfortable while a cast restoration is being fabricated. A good provisional restoration should satisf...

Lec.6 PROVISIONAL RESTORATION (TEMPORARY RESTORATION) Its important that the prepared tooth or teeth be protected and that the patient is kept comfortable while a cast restoration is being fabricated. A good provisional restoration should satisfy the following requirements: 1. Pulpal protection: It should prevent the conduction of temperature extremes and the margin should be well adapted to prevent leakage of saliva. 2. Positional stability: The tooth should not extrude or drift in any way. 3. Occlusal function: Being able to function occlusally on the provisional restoration will aid patient comfort and also prevent tooth migration. 4. Easily cleaned: This will help the gingival tissue to be kept healthy and reduce post cementation problems. 5. Non-impinging Margins: it is of the utmost importance that the gingival margins of the provisional restoration not impinge upon the gingival tissue. The resultant inflammation could result in hypertrophy, gingival recession, or at the very least gingival hemorrhage during cementation. 6. Strength and retention: The restoration must stand up to forces that it’s subjected without breaking. 7. Esthetic: In some cases, they must provide good cosmetic results. Types of provisional crowns: I- Ready made crowns: 1-Metal crowns: Mainly used for posterior teeth. They are made of stainless steel, nickel – chromium, or aluminum and the last one is the most useful because it’s soft. The metal crowns are of 2 types:  Flat topped cylindrical types.  Morphologically contoured type. Disadvantages include: 1- Unpleasant taste. 2- Unacceptable esthetic. 3- Rapid weariness of the crown. 1 Clinical procedure:  Select the proper size and shape of the provisional crown.  Trim the margin to be fit to the finishing line and to accommodate the vertical height of the prepared tooth.  Seat the crown over the tooth and check the margins and the occlusion.  Smooth the margin with a stone bur.  Cementation with ZOE in the abutment. 2- Celluloid crown forms: It’s mainly used for anterior teeth, but can be used for posterior teeth also. It acts as a mould for construction of provisional restoration. Clinical procedure: Coat the tooth after preparation with Vaseline to facilitate removal of the crown. Make 2 holes in the in the corners of the crown to facilitate the removal of the excess material; then we cut it to the same margin of the tooth. Then fill the mold with provisional crown materials with same shade of the tooth; then place it over the tooth, until set. (If the material is exothermic, you have to remove it from the tooth at the simplistic stage so the final polymerization occurs outside the mouth) After that take it out and remove any excess material and then replicate on the tooth and check occlusion, contact points, fitness and extension. Then polish it and temporally cements it. 3- Acrylic ready-made crown: It’s mainly used for anterior teeth. It is supplied with different sizes and shades. After choosing the proper size and shade the procedure is similar to that of aluminum crown. II- custom made provisional restoration: Direct and indirect construction of crown and bridge. A) Direct impression method:  A preoperative impression with alginate or silicon rubber base is made and stored until complete preparation is made.  Coat the tooth with separation medium.  Mix the provisional crown and bridge acrylic and load the tray on the position of the prepared tooth only and insert it inside the patient mouth. 2  After complete polymerization (if the reaction is exothermic you have to take it out from the patient mouth before that), the formed crown is removed and any excess material is removed and we check occlusion and the margin, then cementation by temporary cement. B) Indirect method: To prevent tooth irritation, we can take 1 preoperative & 2 postoperative impression. One of them pours it with quick set stone. After it sets remove the cast & repeat the same steps of direct method on the cast after putting separating medium. a) No heat and monomer to the tooth. b) Better margin. c) Less chairs time. Custom provisional bridge: When a bridge is to be made, the provisional restoration should also be in the form of a bridge rather than individual provisional crowns. 3 A preoperative cast is prepared, we put a partial denture tooth in the edentulous area; and then by using a thermal vacuum machine, template celluloid acetate is made as a mould to fabricate the provisional bridge. The celluloid is 1-4 mm in thickness; it’s heated and then placed over the cast and pulled by vacuum over the cast to take its shape. Then we cut this sheet keeping half a tooth from each side to act as a stopper and 0.5 mm below the margin. Then we load it with the auto-polymerizing resin, place it on the teeth after coating with Vaseline and ask the patient to bite. After setting remove any excess and temporary cement it. Provisional post crown tech. Preformed: Ready-made provisional crown having a post inside. So, you can trim and adapt them to be seated on the prepared tooth. Custom made: This can be accommodated for in the use of a standard acrylic crown by placing a piece of a paper clip or other wire into the canal and placing the acrylic filled crown; down over that. After setting you can remove it with the wire attached, and then cement it. Temporary cement: 4 A wide variety of temporary cements are available; most of them based on zinc oxide and eugenol. 5