HITKARINI DENTAL COLLEGE & HOSPITAL

Department Of Prosthodontics

Seminar Report On – Re l in ing & Rebas ing In Complete Denture

Guided By- Submitted By-Dr. Sumathi Irfan Zunzani

BDS – Final year

Table of ContentsIntroduction Treatment Rationale Definitions :- Relining & Rebasing Objectives Common Indications For Relining &

Rebasing Contraindications General Complaints General Consideration Prior To

Reining Or Rebasing Materials UsedPretreatment Procedures :- Tissue Preparation

Denture PreparationTechniques :-

Clinical ProceduresLaboratory ProceduresChair Side Technique

Conclusion

Introduction

A number of changes can occur in tissues that support complete denture., these changes can entirely be avoided, and the need to “servicing” complete denture to keep pace with the chanaging foundations becomes mandatory. The clinical efforts that aim at prolonging the useful life of complete dentures involve a Reline or Rebase procedure.

Treatment RationaleAs the denture foundations

change, the impression surfaces of dentures cease to fit the tissue properly . The procedure used is a reining one, & the dentist achieves this by adding new denture base materials to the existing denture base , thereby refitting the denture.Rebasing of dentures is

undertaken when the dentures need to be refitted & simultaneously reoriented as well. This is done so as to compensate for vertical & horizontal changes in both dentures orientation. In rebasing a resurfacing of fitting surface of a denture is also involved.

ReliningThe procedure used to resurface the tissue surface of a denture with new base material to make the denture fit more accurately. -- GPT

OrThe process of adding base material to the tissue surface of the denture in a quantity sufficient to fill the space, which exist between the original denture contour and the altered tissue contour. – SHARRY

Rebasing Rebasing is a process of replacing all the base material of a denture. Only the original teeth and their arrangement remain.

OrIt consists of replacing all of the denture base with new material. -- SHARRY

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.

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, granular.

Crazing of the material

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 required

Common Indications for Relining and RebasingSocioeconomic constraints

New denture costs are unaffordable

Physical/ mental state of the patient.

Chronically ill patients

Geriatrics

Mentally compromised individuals

ContraindicationsExcessive resorption of the alveolar

ridgeHighly inflamed/ abused soft tissuesPoor, unacceptable estheticsTMJ problemsUnsatisfactory jaw relation

Horizontal, vertical and orientation relationsSevere osseous undercuts which require

surgical correctionSevere speech problems

General ComplaintsAfter a period of successful denture wear

the patient complains ofLooseness

Ill-fitting dentures with loss of stability and retention.

General soreness and inflammationChewing inefficiency over a period of timeAesthetic problems.

General Consideration Prior to Relining Or Rebasing

Satisfactory VDOCO should coincide with CR.Satisfactory estheticsHealthy oral tissuesAdequate denture base extensionsAdequate load distribution on the basal

seatSatisfactory speechSuitable/healthy soft tissues with out

undercuts

Materials1. 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 activated

Pretreatment Procedures The clinical procedures of relining and

rebasing includes both tissue and denture preparations

1.Tissue Preparation:A). 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.

B) Use of Tissue Conditioner4. Extensive tissue abuse5. Pt. cannot leave the dentures out for

tissue recovery.6. 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.

C). Surgical management:Excessive hypertrophic tissue should be

surgically removed. The denture can be used as a surgical splint.

Denture Preparation

6. 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.

7. Reduction of sharp and overextended borders.

8. Pressure areas in the tissue surface of the dentures should be relieved.

9. Borders should be shortened to allow space for new impression material.

10. All undercuts should be removed.

Techniques

Clinical procedures

Static Methods:

Open Mouth Technique

Closed Mouth Technique

Functional Method

Laboratory procedures

Articulator Method

Jig Method

Flask Method

Chair side technique

Clinical proceduresStatic Method-

Open Mouth Technique:- Given by Carl O. Boucher. Reining & rebasing of both upper &

lower dentures at the same time. Dentures are used as special trays for

making secondary impression. ZnOE is the material of choice , then the impressions are made.

After impression a new Centric Relation is recorded.

Advantages:Selective Trimming helps to make

selective pressure impression.Interoccusal record is reliabe b/c jaw

relation is under consideration.

Disadvantages:Difficult procedure b/c more clinical

and lab work is involved.

Closed Mouth Technique:-Relining or rebasing can not

be done simultaneously for maxillary & mandibular dentures.

There are 4 techniques:-i. Technique Aii. Technique Biii. Technique Civ. Technique D

Technique A:-Centric relation (inter-occlusal

record) is recorded using wax or compound 1.5 to 2 mm relief should be given to large undercuts. Borders are reduced by 1 to 2 mm excepted the posterior region.

The centre portion of the palate in the denture can be removed for visibility in positioning the maxillary denture during impression making.

Border moulding is done & impression is made from ZnOE impression material . Patient is asked to close lightly to interocclusal record & if the palatal portion is cut, quick setting plaster should be used to make impression.

Advantages-Palatal opening will allow better seating of

denture & alleviate the increase in vertical dimension.

Pre-made interocclusal record helps to position the denture during impression making.

It also helps in orienting dentures in an articulator.

2 step procedure – Reduces possibility of moving the maxillary denture forward during final impression.

Disadvantage-Simultaneously maxillary & mandibular

dentures are not relined or rebased.

Technique B :-o Existing Centric relation is used.o Dentures are prepared as Technique A.o Border moulding is done using low fusing

Impression Compound.o Impression wax (Iowa wax) is used for

impression.

Impression is made in 2 steps-o Ist Step- Impression of all areas except

labial flange & alveolar crest in b/w canines is recorded.

o IInd Step- Labial flange & alveolar crest in b/w canines is recorded.

Advantage – It will reduce the extreme forward movement of the denture.

Disadvantage - Wax distort easily.

Technique C:-o Existing centric relation is used.o Denture prepared as in Technique A.o Labial & palatal flanges are perforated to

decrease the pressure inside dentures during the impression making.

o Border moulding & impression making is done.

Technique D:-o Existing centric relation is used.o Denture prepared as in Technique

A. Borders & shortened & made flat.

o Large opening is made at mid palatal region.

o Adhesive tapes are attached over the buccal & labial surfaces of both debtures 2 mm above the denture borders.

o Dental plaster & ZnOE is used for impression.

o Plaster of paris used for palatal portion.

o After impression making, a deep groove is cut into labial & buccal surfaces of the dentures at the junction of impression material & adhesive tape, & filled with molten wax.

o Wax at the edge is used to record sulcus.

Advantages – Same as Technique A.

Disadvantage – Existing centric relation may cause some pressure points & faulty impressions.

Procedure of Technique “D”

Functional Method:- Given by Winkler.

Dentures are not required for laboratory procedures.

Fluid Resin (tissue conditioners) are used as impression material.

Tissue conditioners are usually soft liners with following characteristics :-

o Easy to use.o Excellent for refitting C.D.o Capable for retaining for man weeks.o Good in dimensional stability.o Good in bonding to resin denture base.

Procedure- Avoid night wear of the denture. Occlusal errors should be corrected so Centric

Occlusion coincides with Centric Relation. Tissue surface is reduced to accommodate tissue

conditioning material. Tissue surface is dried & tissue conditioning

material is placed. It should flow evenly as a thin layer to cover the entire impression surface of denture & its borders.

.

Now the denture is inserted & the patient’s mandible is guided to Centric Relation, in order to stabilize the denture & the material is allowed to set . Once the material is set impression is removed & excess material is trimmed.

If poor recording of borders has been done b/c of un-supported area the border moulding is done with green stick compound.

After 3 to 5 days dentures are examined for depressed areas which should be relieved. The material should be renewed periodically (once in a week) till tissue healing is complete.

Then impression with ZnOE is taken over the tissue conditioner material & a cast is poured immediately. During the previous visit an accurate orientation record of maxillary denture should be recorded using a Face Bow.

Laboratory proceduresArticulator method:- Impression is obtained. Cast is poured. Maxillary cast is mounted on

articulator with face bow. Mandibular denture is mounted using

an inter-occlusal record, if occlusal discrepancy is present.

For relining the required amount of tissue surface of the existing denture is trimmed always using an acrylic bur. If rebasing is to be done, the denture base should be trimmed to just leave 2 mm of acrylic around the existing teeth.

After trimming the dentures are placed in the articulator & waxed up without altering the vertical height.

Jig method:-Two types of jigs are there-

1. Hooper’s Duplicator – Having 3 pillars.

2. Jectron Jig – Having 2 pillars.

Flask Method :-Procedure-

Chair Side Procedure

The method makes use of acrylic that could be added to the denture & allowed to set in the mouth to produce instant relining/rebasing.

Disadvantages- Material produces a chemical burn in oral

mucosa. Material is porous & develops a bad odour. Poor color stability. Material is not easy to remove if not placed

correctly.

Now-a-days Visible light cure resin is used.

Conclusion :-Each of the method can produce

satisfactorily result. Impression materials include both auto polymerizing resin & tissue conditioners. Success depends on both clinical & laboratory skills of the operators. Choice of treatment whether to perform relining or rebasing depends on the condition of the adaptation of denture with the denture foundations.

ReferenceBoucher's Prosthodontic

Treatment for Edentulous Patients.

Essentials of Complete Denture Prosthodontics by Sheldon Winkler.

gr.dentistbd.com