Relines and Rebases

1. Relines and Rebases Improving the Adaptation of Existing Dentures

2. Rebase • Replacing entire denture base • Flasking, heat-cured acrylic • Usually porcelain teeth

3. Reline • Resurfacing the tissue surface • Jig used to maintain vertical dimension & occlusal contacts with cold-cure acrylic Or • Reprocessing with heat cure

4. Indications Denture no longer fits residual ridge Retention, stability are lacking PLUS • Occlusion is acceptable • Vertical dimension is acceptable • Denture teeth/gingival contours acceptable

5. Contraindications Complaints of a loose denture DOES NOT, in itself, constitute evidence of a lack of fit and stability

6. Determine Cause of Looseness • Pivoting on bony structures • PIP • Occlusal interferences • Tactile, articulating paper, remount • Inadequate posterior palatal seal • Pull upward & outward on lingual of canines

7. Evaluate Cause of Looseness • Coronoid interferences • Side to side movements, PI{P • Flanges overextensions • Pull on the cheeks, lips, patient move tongue • Tight pterygomandibular raphe

8. Relines Will Only Solve Retention Problems Related to Denture Base Adaptation Retention problems must be diagnosed as to their cause

9. Types of Relines • Processed or chairside • Impression or functional technique • Hard acrylic or resilient • Permanent, temporary • Complete or partial dentures

10. Processed Acrylic Permanent Complete Denture Relines • Make impression for least stable denture first • Easier to stabilize the other denture • Reference for occlusion & vertical dimension

11. Impression Technique Difficult to reline without: • Encroaching on interocclusal space • Displacing the supporting tissues • Altering occlusal contacts USE CARE

12. Positioning the DentureOVD & Occlusion

13. Adjust Occlusion • Obtain stable occlusal contacts • Remount & adjustment may be required • Assess need for tissue conditioning

14. Remove Tissue Undercuts Allows impression to be removed from cast without breaking cast or denture

15. Clean the Denture

16. Border Mold • Relieve borders 2 mm short of vestibule • Border mold with compound • Maxillary posterior border at vibrating line (indelible stick)

17. Reduce Tissue Base • 1 mm if acceptable interocclusal distance • Use guide grooves • If interocclusal distance is excessive, relief may not be required • Perforate denture with #4 round bur

18. Impression Material Polyvinylsiloxane • Ease of use • Cleaning, removal from undercuts • Requires adhesive carried to the external surface of denture borders

19. Impression Procedure • Load carefully • Excessive material can reduce freeway space • Dry tissues

20. Impression Procedure • Seat denture anteriorly • Slowly rotate posterior into place • Ensure denture is not too far forward

21. Verifying Position • Patient closes lightly until first contact • If occlusal interdigitation is poor, physically move denture • Maintain position until set

22. Evaluate Impression • Trim impression to posterior border • Place / mark the posterior palatal seal • Check retention, extension, periphery • Remove excess (occlusal, facial etc.)

23. Check relations intraorallySend to lab for processing

24. Deliver ASAP, usually next clinic Same day in practice, if possible

26. RemountAdjust Occlusion

27. Impression Technique Advantages • Only two appointments needed • Tissues are captured at rest (less possibility of distortion) • Allows for greater extension of peripheries • Allows placement of functional posterior palatal seal

28. Impression Technique Disadvantages • Possible alteration in VDO, occlusion, facial support • No chance to test retention and comfort under function

29. Functional Relines (Lynal, Visco-gel) • Similar procedure • Minor variations

30. Functional Relines • Cannot extend borders greater than 4 mm • Distorts too easily • Grossly under extended, use impression technique

31. Functional Relines • Material requires greater thickness for accuracy • Usually need to reduce denture to allow for thickness

32. Variation in Accuracy of Materials (Visco-gel> Coe-Comfort)

33. Lynal • 10 ml powder : 2 ml liquid, mix 30 sec • If borders short or too thin, add more powder for increased viscosity • Thicker consistency can be formed into a 3 - 4 mm rope and placed around borders

34. Lynal • For tissue base, mix as per instructions • Place intraorally • Remove excess with cotton swab prior to set

35. Set time: 8-10 minute • Lightly border mold • During setting, allow patient to: • Talk • Swallow • Lightly occlude

36. Remove Excess • Reduce material on flanges with HOT scalpel or knife • Remove from teeth, oral surfaces • Patient wears reline home

37. Patient Returns in 24-48 Hours • A cast is poured within 2 hours • Otherwise, accuracy compromised

38. Functional Impression Advantages • Functionally molds peripheries • Ability to assess patient comfort and retention prior to reline proper

39. Functional Impression Disadvantages • Variability of materials, handling characteristics • Resiliency masks overextensions which can subsequently irritate, when converted to acrylic resin

40. Functional ImpressionDisadvantages • Dimensional stability variable • Patient care • Pouring of casts • Can' t significantly increase borders • Do not use simultaneously as a tissue conditioner

41. Partial Denture Relines • Similar procedures • Ensure rests, direct and indirect retainers are fully seated • Seat with pressure over the rests, NOT the distal extension bases

42. Partial Denture Relines • Allow no impression material under rests or guiding planes • If so, remake impression

43. Partial Denture Clinical Remount • If required, a new cast must be made • Make an alginate impression with the RPD in place

44. Partial Denture Clinical Remount • Block out undercuts on the framework while RPD is in the impression • Pour the model with the partial denture in place