relining and re basing of complete denture

1. 2020
SUPERVISED BY:
DR. MUSTAFA SAMEER

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Al-Rafidain University College
Dentistry Department
Prosthodontics
Relining and
rebasing of
complete denture
Ghadeer abdulbasit fat'hi
Grade five
GroupA3

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Introduction
Relining : It is the procedures used to resurface the tissue-side of a denture
with new material layer, thus producing an accurate adaptation to the
denture foundation area. It is usually carried out when the fitness of the
denture has been deteriorated and it is not necessary to construct a new one.
Rebasing : It is the laboratory process of replacing the entire denture base
material on an existing prosthesis, without changing the dental arch, and the
occlusal relationship. General considerations necessary to determine whether
a complete denture reline should be attempted or a new denture constructed
have been presented. Specific evaluation procedures, including the
examination and diagnosis of the patient and the complete denture(s) along
with a checklist of complicating factors, have been discussed
. When the fit of a removable complete denture is diminished as a result of
progressive alveolar bone reduction, relining or rebasing might be indicated.
In clinical practice, a degree of confusion exists concerning the concepts
relining, and rebasing. Relining is resurfacing the tissue side of a denture
with a new material to fill the space which exists between the original
denture contour and the altered tissue contour. Rebasing is resurfacing the
fitting surface of a denture by replacing the entire denture base with new
material, also to fill the space which exists between the original denture
contour and the altered tissue contour. In particular, attention is given to 3
specific forms ofrelining and rebasing which serve to restore the
maxillomandibular relationship, to extend effectively the palatal denture
surface of the maxillary denture and to reline or rebase an implant-supported
overdenture.

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Indication of relining and rebasing :
When observed clinical changes include:
1.Loss of retention and stability.
2.Loss of occlusal vertical dimension.
3.Loss of support for facial tissues.
4.Horizontal shift of dentures: in correct occlusal relationship.
5.Reorientation of occlusal plane.
Contra indication of relining and rebasing :
1.When there is increased vertical dimension (insufficient interarch space).
2.Poor esthetic and incorrect position of teeth.
3.Unsatisfactory jaw relationship in the denture.
4.Excessive resorption of residual ridge.
5.Severe osseous undercuts.
6.Dentures causing major speech problems.
7.Temporomandibular joint problems.
General Considerations (Diagnosis)
A thorough examination of the patient and the denture must
be accomplished before commencing the therapy.
The following points should receive special consideration:-
1.Vertical dimension.
2.Centric occlusion should coincide with centric relation
3.The size, shape, shade, and arrangement of the artificial
teeth must be satisfactory.
4.The oral tissues should be in optimum health.
5.The posterior limit of the maxillary denture is correct.
6.Adequate denture base extension
7.The denture base extensions ensure distribution of
masticatory forces over as large an area as possible.
8.The interocclusal distance is correct
9.Speech is satisfactory
10.Redundant tissue or severe osseous undercuts

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Preliminary treatment
Tissue preparation
Hypertrophic tissues oral mucosa should be free of areas of irritation.
Removal of the dentures from the mouth during sleep is a must.The
dentures should be left out of the mouth at least two to three days before
making final impression.
.Daily massage of the soft tissue
Denture preparation
he tissue surface of the denture.Pressure areas of t-
Minor occlusal disharmony is corrected by selective-
Grinding..
-Small border in adequacyes are corrected..
-A correct posterior palatal seal area should be established
before the final impression.
*** there are many things should be avoided in any technique to fit
complete denture :
1.Do not increase the occlusal vertical dimension.
2. do not permit the maxillary denture to move forward during
impression making.
.3.Ensure that centric relation and centric occlusion are identical
.4.Ensure that an accurate posterior palatal seal has been established
5.an equal thickness of final impression material should be used .
Relining can be achieved in one of two ways :
Direct
( chair side )
Indirect
( laboratotry side )

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Material used for relining
Properities :
 high shear bond strength to denture base materials.
 superior resistance to stain.
 low water sorption.
 no soluble components (low solubility).
 color stability.
 optimal hardness for specific lining material.
 high fatigue limit.
 increased transverse strength.
 minimal dimensional change during polymerization (dimensional stability).
 ease of finishing.
 abrasion resistance.
 tissue compatibility.
 absence of taste and odor.
 low exothermic temperature release.
 absence of free methyl methacrylates .
1.Soft Denture Liners
Soft denture liner materials have become an asset to the technician and clinician
because of their viscoelastic properties. These materials act as shock absorbers and
tissue conditioners that can reduce and distribute occlusal forces to the underlying oral
structures during function while enhancing patient comfort.
These materials may be selected for the treatment of the following conditions:
 atrophic ridges.
 bone undercuts.
 denture(s) opposing natural teeth.
 reduced thickness and viscoelasticity of the mucosa.
 pain from gingival irritation.
 maxillofacial defects.
 Traumatic.
 pathologic tissue loss.
2.Hard Denture Liners
Hard denture liners are generally used in prosthetic dentistry to reline immediate
dentures, for selected RPDs, and for interim dentures until a final denture is
completed. Hard liners can be used when there is an adequate residual ridge, resilient
mucosa, and mature and healthy supporting structures. These materials should be
selected for the treatment of an unstable and ill-fitting denture.
3. Ufi Gel SC(Soft Relining Agent)
The Ufi Gel SC consists of three basic components. These include the adhesive, the reline
materials, and the glaze. The adhesive is composed of a reactive polymer, a special silane,

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and a commonly used solvent. The adhesive is easily applied to the denture, and after 1
minute the ready-to-use reline material can be applied straight from the cartridge. The reline
material is composed of traditional A-silicones and special catalysts. The glaze consists of a
two-component A-silicone, which smooth and seals any trimmed areas of the relining
material to prevent bacterial or fungi penetration.
4.Ufi Gel Hard
This agent, by VOCO, is a new type of hard reline material in direct application cartridges,
which is used directly in the oral cavity. The material is methyl-methacrylate its free and
adhesively bonds to the denture base firmly and permanently. Furthermore, no exothermic
heat characterizes the system during polymerization. Consequently, the curing process can
occur entirely in the patient’s mouth, which in turn assures an accurate fit .
Cold cured acrylic or tissue conditioner material is used, but are not very
durable. Direct relining is less time consuming.
1.The fitting surface of the denture is cleaned, roughened, and slightly
reduced.
2.The flanges are trimmed (to reduce danger of overextension) and the
undercuts removed.
3.Put lubricant over polished surface to prevent the new resin material to
adhere on it.
4..The new self-curing relining material is then mixed and applied to the
fitting surface.
5. The denture is inserted and the patient asked to bite gently on the
denture to ensure that the occlusion is not altered by the procedure.
6.Border molding can then be carried out.
7.The denture is kept in situ for about 5 minutes after which it is removed
and carefully examined.
1.The fitting surface is cleaned, the undercuts are removed and the flanges
are shortened.
Produre of direct relining
Procedure of indirect relining

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2.Minor defects and extensions can be corrected.
3.A wash impression by zinc oxide eugenol is making with the old denture,
with the patient in light occlusal contact.
Laboratory procedure
1. Beading and boxing of the impression, then pouring the boxed
impression with stone material.
2. The denture and the cast are not separated, but any excess
impression on the teeth or facial surfaces of the base is removed,
then the denture flasked in the usual manner.
3. (Zinc oxide eugenol) elimination in hot water for 5 minutes; then
separated and all the impression material is cleaned from the cast
and the denture base.
4. Painting the cast with a separating medium.
5. Paint the surface of the denture with cotton pellet moistened with
monomer.
6. Mix the acrylic resin and place it in the flask (the new relining
material should be compatible with the old denture base material
chemically and esthetically).
7. Curing the heat cured resin.
8. The denture deflasked and the cast removed from the denture then
polish the denture; the relined denture is ready to be inserted in the
patient mouth.
-Rebasing procedure is the same as those for relining with some
differences:
1. Impression is made and a cast is poured in the denture as in relining
procedure.
2. The denture with the cast is mounted on an instrument as Hooper
duplicator or Hanau articulator with mounting jig that maintains the
relationship of teeth to the cast.
3. The old denture base is cut and removed.
4. The original teeth are re-waxed in their previous positions on the cast.
5.The denture is then processed in the laboratory as for relining.
Procedure of rebasing

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6. The denture de flasked and the cast removed from the denture then
finished and polish the denture ,the relined denture is ready to be inserted
in the patient mouth.
Important notes :
Even if you take excellent care of your mouth and dentures, regular replacement is
normal. The American College of Prosthodontists recommends that dentures should
be relined or replace every five to 10 years to keep the underlying bone and gum
healthy.
Now research has shown that loosing your teeth will actually shorten your lifespan.
...
Replacement of missing teeth with partial dentures and complete dentures results
in a lower bite force than when we use bridges and implants.
eryevreplacementTypically, dentists like to follow up and have the patient consider a
to determine if thedenturesfour to six years at least. A dentist will check on your
for many more years todenturesmaterials have deteriorated at all or if you can use your
come.

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Verlag, Heidelberg1965.
-Coburn W.A. Century of Standard Maxillary and Mandibular Impressions
With Refinements. J. Prosthet. Dent. 1953; 3: 29.
-Ned Tijdschr Tandheelkd 2011 Nov;118(11):545-51.
- Dootz ER, Koran A, Craig RG. Comparison of the physical properties of
11 soft denture liners. J Prosthet Dent. 1992;67(5): 707-712.
- Arena CA, Evans DB, Hilton TJ. A comparison of bond strengths among
chairside hard reline materials. J Prosthet Dent.1993;70(2):126-131.
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Dent Assoc. 1995;126(4):503-506.
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laboratory-polymerized permanent soft-liner during 1 year. J Prosthodont.
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- Hayakawa I, Akiba, N, Keh E, et al. Physical properties of a new denture
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Dent. 2006;96(1):53-58.
- Craig RG. Restorative Dental Materials, 7th ed. St Louis, Mo: The CV
Mosby Co, 1985:495.
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Prosthet Dent. 1987;57(4):512-519.