Relining and rebasing


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Relining and rebasing

  1. 1. Relining and Rebasing Final Year BDS 31 – 05 - 2012
  2. 2. Relining The procedure used to resurface the tissue side of a denture with new base material, thus producing an accurate adaptation to the denture foundation area. Or Relining is the procedure used to resurface the tissue side of a denture with new base material.2 AMZ June 1, 2012
  3. 3. Rebasing Rebasing is a process of replacing all the base material of a denture. Only the original teeth and their arrangement remain. Or The laboratory process of replacing the entire denture base of an existing prosthesis.3 AMZ June 1, 2012
  4. 4. Objectives The main objectives of relining or rebasing are to:  Re-establish the correct relation of the denture to basal tissue.  Restore stability and retention  Restore lost occlusal and maxillo-mandibular relationship.4 AMZ June 1, 2012
  5. 5. Common Indications for Relining and Rebasing  Imperfection in the denture base  Defects in the impression surface of the denture due to  Improper handling of the tissues during impression making.  Processing defects  Porosities, shrinkage/contraction, gaseous, gr anular.  Warpage/crazing of the material  Defects in the polished surface5 AMZ June 1, 2012
  6. 6. Common Indications for Relining and Rebasing  Alveolar resorption  Continued resorption of the residual alveolar ridge under the complete denture.  Decreased occlusal vertical dimension  Due to faulty techniques  Immediate dentures  Regular periodic relines are required6 AMZ June 1, 2012
  7. 7. Common Indications for Relining and Rebasing  Socioeconomic constraints  New denture costs are unaffordable  Physical/ mental state of the patient.  Chronically ill patients  Geriatrics  Mentally compromised individuals7 AMZ June 1, 2012
  8. 8. Contraindications  Excessive resorption of the alveolar ridge  Highly inflamed/ abused soft tissues  Poor, unacceptable esthetics  TMJ problems  Unsatisfactory jaw relation  Horizontal, vertical and orientation relations  Severe osseous undercuts which require surgical correction  Severe speech problems8 AMZ June 1, 2012
  9. 9. General Complaints After a period of successful denture wear the patient complains of  Looseness  Ill-fitting dentures with loss of stability and retention  General soreness and inflammation  Chewing inefficiency over a period of time  Aesthetic problems.  Decreased chin nose distance  Prominence of chin9 AMZ June 1, 2012
  10. 10. Selection of the patient  Satisfactory OVD  CO should coincide with CR.  Satisfactory esthetics  Healthy oral tissues  Adequate denture base extensions  Adequate load distribution on the basal seat  Satisfactory speech  Suitable/healthy soft tissues with out undercuts10 AMZ June 1, 2012
  11. 11. Materials 1. PMMA • Heat cured acrylic resin • Cold cured acrylic resin 2. Modifications of PMMA • Butyl meth acrylate 3. Soft liners/ tissue conditioners • Plasticized acrylic resin • Chemically activated…. short term denture liners • Heat activated…. long term denture liners • Vinyl resins • Silicone materials  Chemically activated  Heat activated11 AMZ June 1, 2012
  12. 12. Techniques  Clinical procedures  Laboratory procedures  Chair side relining technique12 AMZ June 1, 2012
  13. 13. Clinical procedures:The clinical procedures for both relining andrebasing can be achieved by the use of one of thefollowing methods: The static impression technique. The functional impression technique.The clinical procedures of relining and rebasingincludes both tissue and denture preparations.
  14. 14. 1.Tissue Preparation:Tissue Rest:1. Instruct the patient to leave the old dentures out of the mouth at least 8 hours preferably at night.2. The dentures should be left out of the mouth at least two to three days before making the final impression.3. Massage of the soft tissues two or three times a day to stimulate the blood supply and aid recovery.
  15. 15. B) Use of Tissue Conditioner1. Extensive tissue abuse2. Pt. cannot leave the dentures out for tissue recovery.3. Transmission of masticatory forces to the supporting mucosa are equalized by eliminating isolated pressure spots typical of a loose, ill fitting denture.4. The material is renewed periodically every 3 to 7 days.5. When the tissues had returned to a clinically discernible healthy state, the patient is scheduled for making the impression.
  16. 16. c) Surgical management:Excessive hypertrophic tissue should be surgically removed. The denture can be used as a surgical splint.
  17. 17. Denture Preparation1. Balanced occlusion to ensure that uneven contact does not bring about a bodily shift or tilt of the denture when the patient is asked to close together.2. Reduction of sharp and overextended borders.3. Pressure areas in the tissue surface of the dentures should be relieved.
  18. 18. Clinical procedures  Preparation for the impression  Adjustment of occlusion  Jaw relation records18 AMZ June 1, 2012
  19. 19. Laboratory procedures  Articulation method  Reverse flasking method  Jig method19 AMZ June 1, 2012
  20. 20. 20 AMZ June 1, 2012