Relines and Rebases


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Relines and Rebases

  1. 1. Relines and Rebases <ul><li>Improving the Adaptation of Existing Dentures </li></ul>
  2. 2. Rebase <ul><li>Replacing entire denture base </li></ul><ul><li>Flasking, heat-cured acrylic </li></ul><ul><li>Usually porcelain teeth </li></ul>
  3. 3. Reline <ul><li>Resurfacing the tissue surface </li></ul><ul><li>Jig used to maintain vertical dimension & occlusal contacts with cold-cure acrylic </li></ul><ul><li>Or </li></ul><ul><li>Reprocessing with heat cure </li></ul>
  4. 4. Indications <ul><ul><li>Denture no longer fits residual ridge </li></ul></ul><ul><ul><li>Retention, stability are lacking </li></ul></ul><ul><ul><li> PLUS </li></ul></ul><ul><ul><ul><ul><li>Occlusion is acceptable </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Vertical dimension is acceptable </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Denture teeth/gingival contours acceptable </li></ul></ul></ul></ul>
  5. 5. Contraindications <ul><li>Complaints of a loose denture </li></ul><ul><li>DOES NOT, </li></ul><ul><li>in itself, constitute evidence of </li></ul><ul><li>a lack of fit and stability </li></ul>
  6. 6. Determine Cause of Looseness <ul><ul><li>Pivoting on bony structures </li></ul></ul><ul><ul><ul><li>PIP </li></ul></ul></ul><ul><ul><li>Occlusal interferences </li></ul></ul><ul><ul><ul><li>Tactile, articulating paper, remount </li></ul></ul></ul><ul><ul><li>Inadequate posterior palatal seal </li></ul></ul><ul><ul><ul><li>Pull upward & outward on lingual of canines </li></ul></ul></ul>
  7. 7. Evaluate Cause of Looseness <ul><li>Coronoid interferences </li></ul><ul><ul><li>Side to side movements, PI{P </li></ul></ul><ul><li>Flanges overextensions </li></ul><ul><ul><li>Pull on the cheeks, lips, patient move tongue </li></ul></ul><ul><li>Tight pterygomandibular raphe </li></ul>
  8. 8. Relines Will Only Solve Retention Problems Related to Denture Base Adaptation <ul><li>Retention problems must be diagnosed as to their cause </li></ul>
  9. 9. <ul><ul><li>Processed or chairside </li></ul></ul><ul><ul><li>Impression or functional technique </li></ul></ul><ul><ul><li>Hard acrylic or resilient </li></ul></ul><ul><ul><li>Permanent, temporary </li></ul></ul><ul><ul><li>Complete or partial dentures </li></ul></ul>Types of Relines
  10. 10. Processed Acrylic Permanent Complete Denture Relines <ul><li>Make impression for least stable denture first </li></ul><ul><li>Easier to stabilize the other denture </li></ul><ul><ul><li>Reference for occlusion & vertical dimension </li></ul></ul>
  11. 11. Impression Technique <ul><ul><li>Difficult to reline without: </li></ul></ul><ul><ul><ul><li>Encroaching on interocclusal space </li></ul></ul></ul><ul><ul><ul><li>Displacing the supporting tissues </li></ul></ul></ul><ul><ul><ul><li>Altering occlusal contacts </li></ul></ul></ul><ul><ul><ul><li> USE CARE </li></ul></ul></ul>
  12. 12. Positioning the Denture OVD & Occlusion
  13. 13. Adjust Occlusion <ul><li>Obtain stable occlusal contacts </li></ul><ul><li>Remount & adjustment may be required </li></ul><ul><li>Assess need for tissue conditioning </li></ul>
  14. 14. Remove Tissue Undercuts <ul><li>Allows impression to be removed from cast without breaking cast or denture </li></ul>
  15. 15. Clean the Denture
  16. 16. Border Mold <ul><li>Relieve borders 2 mm short of vestibule </li></ul><ul><li>Border mold with compound </li></ul><ul><li>Maxillary posterior border at vibrating line (indelible stick) </li></ul>
  17. 17. Reduce Tissue Base <ul><li>1 mm if acceptable interocclusal distance </li></ul><ul><ul><li>Use guide grooves </li></ul></ul><ul><li>If interocclusal distance is excessive, relief may not be required </li></ul><ul><li>Perforate denture with #4 round bur </li></ul>
  18. 18. Impression Material Polyvinylsiloxane <ul><li>Ease of use </li></ul><ul><li>Cleaning, removal from undercuts </li></ul><ul><li>Requires adhesive carried to the external surface of denture borders </li></ul>
  19. 19. Impression Procedure <ul><li>Load carefully </li></ul><ul><li>Excessive material can reduce freeway space </li></ul><ul><li>Dry tissues </li></ul>
  20. 20. Impression Procedure <ul><li>Seat denture anteriorly </li></ul><ul><li>Slowly rotate posterior into place </li></ul><ul><li>Ensure denture is not too far forward </li></ul>
  21. 21. Verifying Position <ul><li>Patient closes lightly until first contact </li></ul><ul><li>If occlusal interdigitation is poor, physically move denture </li></ul><ul><li>Maintain position until set </li></ul>
  22. 22. Evaluate Impression <ul><li>Trim impression to posterior border </li></ul><ul><li>Place / mark the posterior palatal seal </li></ul><ul><li>Check retention, extension, periphery </li></ul><ul><li>Remove excess (occlusal, facial etc.) </li></ul>
  23. 23. Check relations intraorally Send to lab for processing
  24. 24. Deliver ASAP, usually next clinic Same day in practice, if possible
  25. 26. Remount Adjust Occlusion
  26. 27. Impression Technique Advantages <ul><ul><li>Only two appointments needed </li></ul></ul><ul><ul><li>Tissues are captured at rest (less possibility of distortion) </li></ul></ul><ul><ul><li>Allows for greater extension of peripheries </li></ul></ul><ul><ul><li>Allows placement of functional posterior palatal seal </li></ul></ul>
  27. 28. Impression Technique Disadvantages <ul><ul><li>Possible alteration in VDO, occlusion, facial support </li></ul></ul><ul><ul><li>No chance to test retention and comfort under function </li></ul></ul>
  28. 29. Functional Relines (Lynal, Visco-gel) <ul><ul><li>Similar procedure </li></ul></ul><ul><ul><li>Minor variations </li></ul></ul>
  29. 30. Functional Relines <ul><li>Cannot extend borders greater than 4 mm </li></ul><ul><li>Distorts too easily </li></ul><ul><li>Grossly under extended, use impression technique </li></ul>
  30. 31. Functional Relines <ul><li>Material requires greater thickness for accuracy </li></ul><ul><li>Usually need to reduce denture to allow for thickness </li></ul>
  31. 32. Variation in Accuracy of Materials <ul><li>(Visco-gel> Coe-Comfort) </li></ul>
  32. 33. Lynal <ul><li>10 ml powder : 2 ml liquid, mix 30 sec </li></ul><ul><li>If borders short or too thin, add more powder for increased viscosity </li></ul><ul><li>Thicker consistency can be formed into a 3 - 4 mm rope and placed around borders </li></ul>
  33. 34. Lynal <ul><li>For tissue base, mix as per instructions </li></ul><ul><li>Place intraorally </li></ul><ul><li>Remove excess with cotton swab prior to set </li></ul>
  34. 35. Set time: 8-10 minute <ul><li>Lightly border mold </li></ul><ul><li>During setting, allow patient to: </li></ul><ul><ul><li>Talk </li></ul></ul><ul><ul><li>Swallow </li></ul></ul><ul><ul><li>Lightly occlude </li></ul></ul>
  35. 36. Remove Excess <ul><li>Reduce material on flanges with HOT scalpel or knife </li></ul><ul><li>Remove from teeth, oral surfaces </li></ul><ul><li>Patient wears reline home </li></ul>
  36. 37. Patient Returns in 24-48 Hours <ul><li>A cast is poured within 2 hours </li></ul><ul><li>Otherwise, accuracy compromised </li></ul>
  37. 38. Functional Impression Advantages <ul><li>Functionally molds peripheries </li></ul><ul><li>Ability to assess patient comfort and retention prior to reline proper </li></ul>
  38. 39. Functional Impression Disadvantages <ul><li>Variability of materials, handling characteristics </li></ul><ul><li>Resiliency masks overextensions which can subsequently irritate, when converted to acrylic resin </li></ul>
  39. 40. Functional Impression Disadvantages <ul><li>Dimensional stability variable </li></ul><ul><ul><li>Patient care </li></ul></ul><ul><ul><li>Pouring of casts </li></ul></ul><ul><li>Can' t significantly increase borders </li></ul><ul><li>Do not use simultaneously as a tissue conditioner </li></ul>
  40. 41. Partial Denture Relines <ul><li>Similar procedures </li></ul><ul><li>Ensure rests, direct and indirect retainers are fully seated </li></ul><ul><li>Seat with pressure over the rests, NOT the distal extension bases </li></ul>
  41. 42. Partial Denture Relines <ul><li>Allow no impression material under rests or guiding planes </li></ul><ul><li>If so, remake impression </li></ul>
  42. 43. Partial Denture Clinical Remount <ul><li>If required, a new cast must be made </li></ul><ul><li>Make an alginate impression with the RPD in place </li></ul>
  43. 44. Partial Denture Clinical Remount <ul><li>Block out undercuts on the framework while RPD is in the impression </li></ul><ul><li>Pour the model with the partial denture in place </li></ul>