Finishing the Cast Restoration PDF

Finishing the Cast Restoration Prepared by Dr.Adham Nyazi Dr. Malak Bamigdad BDS KAU, Saudi Board in Prosthodontic dentistry Outline: Objectives and procedures Zone 1: internal margin Zone 2: internal surface (intaglio) Zone 3: the spruce Zone 4: proximal cont...

Finishing the Cast Restoration Prepared by Dr.Adham Nyazi Dr. Malak Bamigdad BDS KAU, Saudi Board in Prosthodontic dentistry Outline: Objectives and procedures Zone 1: internal margin Zone 2: internal surface (intaglio) Zone 3: the spruce Zone 4: proximal contacts Zone 5: occlusal surface Zone 6: axial walls Zone 7: external margins Armamentarium Different carbide and diamond burs Stone and rubber burs and wheels Carborundum disks Finishing disks Al2O3 particles and sandpaper Measuring gauge Introduction: After investment, the unpolished restoration must be finished to be ready for cement action. The sprue needs to be removed and the attachment area polished. The finishing and polishing of the cast restoration requires sequential procedures which are divided into zones. The smoother the wax pattern the smoother the casting  Zone 1: Internal Margin Objective: To minimize the dissolution of the outing cement 1mm wide band of metal well adapted to the tooth Procedure: Small carbide bur (No. 1/4 round bur) Careful examination of small nodules If a defect occurs in the marginal area, remake is done Zone 2: Intaglio Objective: No contact between the die and the intaglio surface Uniform space of 25 to 35 microns for the luting agent Procedure: 1/4 or 1/2 round carbide bur On normal circumstances, no finishing required Examination for small nodules Carful seating on the die If the die is abraded, redo impression is required if re-waxing is necessary Marking agents: Water-soluble dies (Liqua-Mark) Solvent-based dies (AccuFilm IV) Powdered sprays (Occlude) Rouge with elastomeric detection paste (Fit Checker) Zone 3: The Sprue Objective: Re-establish proper coronal structure and function Re-contouring the attachment area Procedure: Carborundum separating disk is used to cut the sprue Wire cutters are not recommended The area is then refined with stones and sandpaper disks  Zone 4: Proximal Contacts Objective: To be corrected (or slightly tight) in the patient mouth Procedure: Too tight vs. too loose Proximal contact on the stone can be slightly relieved with a scalpel Mylar articulating film Multiple castings => sequentially examined individually Connectors: should be evaluated and polished carefully Zone 5: Occlusal Surface Objective: Re-establish a static and dynamic occlusion Procedure: Mylar articulating film to indicate high points Flame shaped diamond burs vs. stone burs Measuring gauge Polishing the surface with Rouge on a soft brush (5 microns) Airborne particular abrasion 25-50 micron AL2O3 (20 microns) Zone 6: Axial Walls Objective: For the patient to carry out proper plaque control Procedure: Abrasive particles with a stone bur or rubber wheel The most efficient method for polishing, a sequence of progressively finer abrasives Light pressure is used Finishing vs. polishing Zone 7: External Margins Objective: To produce a highly polished surface that will help in plaque control Procedure: Best to be polished on the tooth Difficult to finish in restricted areas, proximal and subgingival Pay attention to the marginal fit and emergence profile Thank You