PROVISIONAL RESTORATIONS

A good provisional restoration should satisfy the following requirements1. Pulpal protection2. Positional stability. 3. Occlusal function4. Easily cleaned5. Non impinging margins6. Strength and retention. 7. Esthetics

Types of Provisional Restorations zinc oxide-eugenol

small intracoronal inlay

to

provisional crowns

and provisional fixed partial dentures

Prefabricated vs Custom Restorations Prefabricated

only for single-tooth only for single-tooth restorationsrestorations

1. stock aluminum cylinders ("tin cans")

2. anatomic metal crown forms

3. clear celluloid shells4. Tooth colored

polycarbonate crown forms.

Custom crowns and fixed partial dentures Resins

direct or indirect.

Direct vs. Indirect Techniques

on the actual prepared teeth in the mouth.

outside of the mouth

on a cast made of quick-set plaster

direct technique indirect technique

1. Poly methyl methacrylate2. Poly ethyl methacrylate3. Poly vinyl ethyl methacrylate4. Bis acryl composite resin5. Visible light-cured (VLC)

Resins for Provisional Restorations Crown

Type Brand Manufacturer Advantages Disadvantages

Poly(methyl methacrylate)

Alike Cf & Br Resin Duralay Jet

GC America LD Caulk Reliance Dental Lang Dental

Good marginal fit'5 Good transverse strength15 Good polishability15 Durability16

High exothermic heat increase17-18

Low abrasion resistance15 Free monomer toxic to pulp16

High volumetric shrinkage16

Poly(ethyl methacrylate)

Snap Parkeli Biomaterials

Good polishability15 Minimal exothermic heat increase17

Good stain resistance15

Low shrinkage8

Surface hardness15 Transverse strength15 Durability16 Fracture toughness19

Poly(vinylethyl methacrylate)

Trim Harry Bosworth Good polishability15 Minimal exothermic heat increase'7

Good abrasion resistance15

Good stain resistance15

Flexibility8

Surface hardness15 Transverse strength15 Esthetics8 Fracture toughness19

Bis-acryl composite

Protemp II ESPE-Premier Good marginal fit15 Low exothermic heat increase18

Good abrasion resistance15

Good transverse strength15

Low shrinkage8

Surface hardness15 Less stain resistance15 Limited shade selection8 Limited polishability8

Brittle16

VLC uerthane di methacrylate

Triad Dentsply York High surface hardness15

Good transverse strength15

Good abrasion resistance15

Controllable working time20

Color stability15

Marginal fit15 Less stain resistance15 Limited shade selection20 • Expensive11'21 Brittle

Techniques for Custom Provisional Restorations1. Over impression-Fabricated Provisional2. Template-Fabricated Provisional Fixed

Partial Denture

Overimpression-Fabricated Provisional

Over impression-Fabricated ProvisionalDefects, such as a missing cusp (arrow), should be filled in on the cast

Utility wax is placed in the defect

Over impression-Fabricated ProvisionalOverimpression is made from the diagnostic cast

Thin edges in the gingival areas of the overirepression are cut away.

Over impression-Fabricated ProvisionalAlginate impression is made of the prepared tooth

Untrimmed quick-set plaster cast.

Over impression-Fabricated ProvisionalProperly trimmed plaster cast.

The cast is tried in the overimpression before proceeding

Over impression-Fabricated ProvisionalSeparating medium is painted on the plaster cast.

Acrylic resin is mixed in a dappen dish

Over impression-Fabricated ProvisionalResin is placed into the overirnpression

The cast is seated firmly in the overimpression.

Over impression-Fabricated ProvisionalCast held in place with a rubber

Over impression correct seatingoverimpressions: correctly seated (A)

if the cast is pushed to one side (B);

overseating of the cast will produce a provisional restoration (C).

Over impression-Fabricated ProvisionalThe cast can be broken to remove the provisional restoration.

Any plaster remaining in the provisional restoration is removed.

Over impression-Fabricated Provisionalflash is ground off with a carborundum disc

Margins are smoothed with a sandpaper disc.

Over impression-Fabricated ProvisionalOcclusion on the restoration is checked in the mouth.

Occlusion is adjusted outside the mouth

Over impression-Fabricated ProvisionalThe restoration is polished with pumice.

Zinc oxide-eugenol cement is often mixed with a small amount of petrolatum

Over impression-Fabricated ProvisionalAn explorer is used to remove cement from the gingival crevice

Cementation Armamentarium

Template-Fabricated Provisional Fixed Partial DentureA crown form or a denture tooth is placed in the edentulous space on the diagnostic cast

A rope of Mor-Tight is placed around the periphery of the cast.

Template-Fabricated Provisional Fixed Partial DentureThe plastic sheet is secured in the frame of the vacuum forming machine

The plastic sags as it is heated to the proper tempera ture.

Template-Fabricated Provisional Fixed Partial DentureThe frame is pulled down over the perforated stage of the vacuum forming machine

The plastic is cut to remove the template from the diagnostic cast.

Template-Fabricated Provisional Fixed Partial DentureThe plastic can be heated in a wire frame over a Bunsen burner

The plastic sheet is positioned over the diagnostic cast.

Template-Fabricated Provisional Fixed Partial DentureThe plastic template is adapted by exerting heavy force on the impression tray of silicone putty.

The tray full of putty is pulled off the adapted plastic

Template-Fabricated Provisional Fixed Partial DentureExcess is trimmed from the periphery of the template

The quick-set plaster cast should be trimmed back to the dotted line

Template-Fabricated Provisional Fixed Partial DentureThe template is tried on the cast to verify the fit

Some acrylic resin is placed in the interproximal areas of the cast

Template-Fabricated Provisional Fixed Partial DentureResin is placed in the template

The template is held in position with rubber bands

Template-Fabricated Provisional Fixed Partial DentureThe lingual ridge of the saddle (arrow) is removed to open the lingual embrasure of the pontic.

The pontic is trimmed to widen the embrasures and create cleanable contours.

Template-Fabricated Provisional Fixed Partial DentureA silicone putty index is formed over the template on the diagnostic cast

VI.C resin is placed in the clear template

Template-Fabricated Provisional Fixed Partial DentureThe resin-loaded template is forcefully seated on the quick-set plaster cast.

silicone putty index is seated over the template

Template-Fabricated VLC Provisional Restoration

Template-Fabricated VLC Provisional Restoration

The cast with the resin-loaded template is placed in the light-polymerizing unit.

Excess resin is cut off with crown and bridge scissors

Template-Fabricated VLC Provisional Restoration

Monomer is applied to the over impress ion with a needle-tipped liquid applicator.

Enough polymer is applied to turn the surface of the impression dull.

Template-Fabricated VLC Provisional Restoration

Gingival flash is removed and gingival embrasures are opened

The resin-filled shell is seated on the prepared teeth on the cast.

The resin-filled shell is seated on the prepared teeth in the mouth

Template-Fabricated VLC Provisional RestorationImpression material is loaded into a quadrant tray for the over-impression.

Border of the overimpression is trimmed

Template-Fabricated VLC Provisional RestorationA gingival trough is cut with a no. 8 bur in the facial and lingual surfaces of the imprint of the tooth being restored

A midsagittal section of the overimpression and the provisional restoration shows a bulk of material (arrows) near the margins.

Template-Fabricated VLC Provisional RestorationThe catch should be engaged in the slot in the threaded plunger at the back of the base syringe.

The plunger of the base syringe is rotated one full turn to produce one measure of base resin.

Template-Fabricated VLC Provisional RestorationThe catch must be engaged in the slot in the threaded middle plunger at the back of the catalyst syringe.

The threaded middle plunger of the catalyst syringe is rotated one click to produce enough catalyst to mix with one measure of base paste.

Template-Fabricated VLC Provisional RestorationCatalyst and base are mixed on the mixing pad.

Syringe is loaded with mixed resin.

Template-Fabricated VLC Provisional RestorationMixed resin is expressed into the imprint of the tooth for which the provisional restoration is being fabricated.

The rubbery provisional restoration is teased from the tooth.

Template-Fabricated VLC Provisional RestorationThe partially polymerized provisional restoration is removed from the impression.

Techniques for Prefabricated Provisional Restorations

Anterior Polycarbonate Crown

Armamentarium 1. Anterior sectional impression

tray (one only) 2. Alginate 3. Rubber bowl 4. Spatula 5. Quick-set plaster 6. Polycarbonate crown kit 7. Pencil 8. Straight handpiece 9. Acrylic bur 10. Coarse garnet disc on Moore

mandrel 11. Burlew disc on mandrel 12. Large camel-hair brush 13. Cement spatula

14. Dappen dish 15. IPPA plastic instrument 16. Separating medium 17. Monomer and polymer 18. Medicine dropper 19. Muslin rag wheel 20. White polishing compound 21. Miller forceps

22. Articulating paper 23. Paper pad 24. Zinc oxide-eugenol

cement 25. Petrolatum 26. Explorer 27. Mouth mirror 28. Dental floss

Anterior Polycarbonate CrownAn anterior sectional tray is used to make an alginate impression of the prepared tooth

Quick-set plaster cast and the impression in which it was made.

Anterior Polycarbonate CrownMold guide is held adjacent to the cast to select the correct crown size.

With the crown on the preparation, a mark is made at a distance from the labial margin that is equal to the amount by which the crown exceeds the height of adjacent teeth.

Anterior Polycarbonate CrownExcess gingival length that extends beyond the mark is cut off.

Polycarbonate crown after removal of the excess length. The tab is left on at this point to facilitate handling

Anterior Polycarbonate CrownThe preparation and adjacent portions of the plaster cast are painted with separating medium.

The crown filled with resin is placed onto the pre pared tooth on the plaster cast

Anterior Polycarbonate CrownGingival excess created by the expressed acrylic is trimmed back with a garnet disc until the margin coincides with the imprint of the finish line (arrow)

Occlusion is checked with articulating paper.

Anterior Polycarbonate CrownAxial surfaces near the margin are smoothed with a Burlew disc.

Axia! surfaces are polished with white polishing com pound on a muslin rag wheel.

Anterior Polycarbonate CrownAll cement is removed from the gingival crevice with an explorer.

Provisional Crown for an Endodontically Treated Tooth

Preformed Anatomic Metal Crown 1. Minimal tooth preparation 2. Measurement and selection of crown 3. Trimming and adaptation of gingival

margin 4. Occlusal adjustment 5. Cementation

Preformed Anatomic Metal CrownMaxillary second molar with a fractured distolingual

Occlusal clearance is obtained with a diamond or a no. 1 70 bur.

Preformed Anatomic Metal CrownFunctional cusp bevel is placed with the same instru ment

Proximal reduction usually consists of removing an existing amalgam restoration

Preformed Anatomic Metal CrownMeasuring gauge for selecting a preformed metal crown

Mesiodistal measurement of the space is obtained,

Preformed Anatomic Metal CrownGingival margins can be flared slightly on the stretching block.

Marginal ridge height discrep ancy between the restoration and the adjacent tooth is estimated.

ستقیمHم تکنیک توصیه directدر را زیر رزین کدام؟ نمایید نمی

1. Poly methyl methacrylate2. Poly ethyl methacrylate3. Poly vinyl ethyl methacrylate4. Bis acryl composite resin5. Visible light-cured (VLC)