FINISHING AND POLISHING

1. FINISHINGANDPOLISHING

2. The surface of the casting that is retrieved from investment is too rough for use in the mouth.Five preparatory procedures need to be performed on any type of cemented restoration after it has been fabricated

3. PROCEDURES • Preliminary finishing • Try-in & adjustment • Pre-cementation polishing • Cementation polishing • Post-cementation finishing

4. The internal and external aspects of restoration are handled differently. • External surface smooth &perfect uninterrupted transition from restoration to tooth • Rough surface plaque accumulation-injurious to health of periodontal tissue • Try in satin finish after chairside adjustment high luster • Finishing&polishing- accomplished with fixed routine-coarse and fine

5. ABRASIVES AND POLISHING MATERIALS • ABRASIVES:exceptionally hard material that develop sharp cutting edges when they are chipped. • POLISHING MATERIALS:abrasives of softer material that are reduced to extremely fine particle size.

6. COMMONLY USED ABRASIVES AND POLISHING MATERIALS • DIAMOND • SILICON CARBIDE • EMERY • ALUMINIUM OXIDE • GARNET • SAND • CUTTLE • TRIPOLI • ROUGE • TIN OXIDE

7. COMMONLY USED FORMS • SEPARATING DISCS • MOORE’S DISC • HEATLESS STONES • BUSCH SILENT STONES • GREEN STONES • PINK STONES • WHITE STONES • RUBBER WHEEL AND POINTS

8. ZONES OF FINISHING AND POLISHING • ZONE 1:INTERNAL MARGIN • ZONE 2:INTERNAL SURFACE • ZONE 3:SPRUE • ZONE 4:PROXIMAL CONTACT • ZONE 5:OCCLUSAL SURFACE • ZONE 6:AXIAL WALL • ZONE 7:EXTERNAL MARGIN

9. PRELIMINARY FINISHING OF GOLD RESTORATION

10. Inspect under surface of cast under magnification for small nodules or bubbles • Remove nodule with no:330 bur in high speed .Trace negative angles on inside of occlusal surface with tip of bur • Ideally the cast should touch the die only in the marginal region –there should be a slight gap every where else for future cementation. • A uniform space of 25 – 35micrometer necessary • If nodules present removed with round carbide bur

11. Use a separating disc to cut the sprue from the casting • Diagonal cutting plier may be used. • Hold hand piece with a firm pen grasp while cutting the sprue next to the casting • Avoid tipping the disc- if a disc binds in the cut grooves – it may flip the casting out of our hand • After removing the sprue , use separating to trim the remaining portion of sprue attachment on the casting until the contour in that area is continuous with the contour of the restoration surrounding the sprue

12. Use coarse rubber disc-to smooth away the roughness left by the separating disc. • Use finer Burlew/gold lustre blue disc in similar manner after coarse disc-now entire surface smooth with satin finish • Axial surface finished to the margin-do not extend over the margin-seat the restoration on the cast • Adjust the interproximal area-until restoration seats completely with contacting adjacent teeth

13. Adjust occlusion in articulator-centric&eccentric • Remove restoration from working cast and place it back to die • No:0-”bud” finish bur – to smooth grooves on occlusal surface • Smooth cusp tips and blend them into the grooves on the occlusal surface with a small rubber sulci disc • External surface should have a satin like finish produced by Burlew rubber polishing wheel

14. TRY-IN & ADJUSTMENT

15. If careful and gentle no need of anesthesia • Patient’s unimpaired tactile sense can be valuable during adjustment of occlusion • Small safety ring provided by cutting a thin slice from hollow sprue • Attach it to the wax pattern where it will not interfere with occlusion • Thread floss through the ring before trying casting in the mouth.

16. Remove provisional restoration by grasping the buccal and lingual surface with tips of backhaus towel forceps and rocking it to the facial and lingual. • Remove the left cement particles • Wipe of prepared surface with cotton pellet ( dry ) • Wash with luke warm water

17. Evaluation of restoration in following sequence • Proximal contact • Margins • Occlusion • Contour • Esthetics

18. Adjustment of proximal surface contact • Proximal contact – neither too tight nor too light. • Place the restoration on the tooth & seat it with firm finger pressure. • Do not mallet / apply occlusal pressure. • Crown can be removed with Richwilcrown remover • soaked in hot tap water for 1min • Patient closes on the softened cube • Patient opens quickly and forcefully to remove crown

19. Test for proximal contact with waxed dental floss • Satin finish on gold restoration - advantageous- shiny burnished area where tight contact occurs

20. Marginal adaptation • After proximal contact corrected seat restoration and examine margin closely-should not be ; • Overextended • Under extended • Too thick • Open- gap greater than 50µm

21. Various materials used to detect discrepancies • Chloroform & rouge / thinned typewriter correction fluid-painted in the internal surface • Thin layer of dry aerosol indicators – sprayed • DISCLOSING WAX: • Fill restoration ½ full of disclosing wax • Heat in flame to flow the wax & adhere to inner surface • Teeth wet with saliva( avoid sticking of wax) • Wax solidified seat restoration hold for 10 sec then remove

22. Areas of metal – tooth contact –appear as shiny spot devoid of wax • Relief impinging areas with no:30 bur-allow restoration to seat further • Remove disclosing material by swabbing with chloroform and sand blasting • Tooth cleaned with cavilax

23. GOLD MARGIN FINISHING • 2 types of margins- sub gingival & supragingival • Casting placed on prepared tooth and have the patient seat it by closing on plastic bite wafer/wooden stick • Burnishing and marginal adaptation with dull spratley knife(30µm adaptation) • Finishing with white stone (60µm adaptation) • Final precementation smoothening with 3/8 inch cuttle disc

24. POST CEMENTATION FINISHING

25. Occlusion checked • Finishing with fine rubber point • White polishing stone with lubrication (petrolatum) • To inaccessible areas • Fine cuttle disc • Pumice and rubber cup • FINAL POLISHING by – intraoral amalgloss