Repair, relining and Repair, relining and rebasingrebasing

Dr. Amal Fathy KaddahDr. Amal Fathy KaddahProfessor of ProsthodonticProfessor of Prosthodontic , ,

Faculty of Oral &Dental Medicine, Cairo Faculty of Oral &Dental Medicine, Cairo UniversityUniversity

www.egydental.comwww.egydental.com

First Steps In Making A Denture

•Primary impression

•Diagnostic cast

•Custom tray

•Final impression

•Master cast

Impression Impression TechniquesTechniques

Primary impressionsPrimary impressions Conventional techniques Conventional techniques

Template techniquesTemplate techniques

Definitive impressionsDefinitive impressions

I- Conventional techniques I- Conventional techniques

II- Selective pressure techniques II- Selective pressure techniques

III- Functional techniques III- Functional techniques

IV- Reline and rebase techniques IV- Reline and rebase techniques

(including secondary template impressions).(including secondary template impressions).

Complete Complete Dentures Dentures

Repair of Complete Dentures

Dentures may fracture

during function dropped on hard

surface

Key of repair = accurate reassembling & alignment of the broken parts in their original position.

Classification of fractured dentures

I) According to location of fracture

Midline fracture Any part fracture

II) According to extent of fracture

With broken or missing part &/or teeth

Without broken or missing part &/or teeth

IV) According to cause of fracture

Operator Patient

III) According to timing of fracture

Early fracture Delayed fracture

Midline fracture (mainly in maxillary dentures)

Causes:

1) No or insufficient relief in the midline. (M.P.R.) (Early fracture) 2) Ridge resorption with loss of relief effect. (Delayed fracture)

Procedures for repair of midline fracture:

• Broken parts are assembled & fixed together with sticky wax on the polished surface.

• Assembled parts may be strengthened with burs or plastic sticks.

• Any undercut on the

fitting surface is

blocked out with wax

or clay.

• The fitting surface is

painted with

separating medium.

Procedures for repair of midline fracture:

• Stone plaster is poured into the fitting surface. After stone setting, the denture is removed from the cast and cleaned from any traces of sticky wax.• Fractured edges are reduced, widened (8-10 mm) along the fracture line and beveled towards the polished surface to increase bonding surface area.• Dove tail cuts may be made to strengthen the repair joint.

• The cast is painted with separating medium and the denture is secured to the cast with rubber bands.• Self cure A.R. is applied to the modified fracture area until the area is overfilled.

N.B. An alternate method is to

wax and contour the fracture line to the desired form using base plate wax, followed by flasking, wax elimination, packing with self cure A.R. and placing in the flask under press for 2 hrs.• Deflasking, finishing and polishing is then done in the usual manner.

•Relief of the median Relief of the median

palatine raphea.palatine raphea.

• Reline if needed.Reline if needed.

• Remake in some cases.Remake in some cases.

Main cause is falling on the ground or the sink during cleaning.

Types:

I- Fracture with no missing part

Repaired as mentioned.

Any part fracture

II- Fracture with missing or lost part

Procedures:

• An impression is made with the denture placed in patient mouth.• After pouring the cast, either self cure A.R. is applied to replace the missing part, or wax is added and carved to resemble the broken denture part, followed by flasking, packing, curing, finishing & polishing.

• Fractured teeth are cut away with burs.• On the lingual side, enough acrylic is removed and dove tailed. • Teeth of same size, shape & shade are positioned in proper alignment and waxed with base plate wax.

III- Fracture with broken or missing teeth

Procedures:

• A plaster index (key) is made to record & secure the position of waxed teeth.• Teeth to be repaired are removed together with all wax around them.• Teeth are then put back exactly in their original position aided by plaster key.• Self cure acrylic resin is added from the lingual side until repair area is over built. It is then covered with tin foil.• After curing, the index is removed and the denture is finished and polished.

Def: Resurfacing or correction of denture adaptation to underlying tissues by the addition of a new resin material to its fitting surface without changing its occlusal relation.

Relining of Complete Dentures

AdditionAddition of Material to the tissue side of of Material to the tissue side of a denture to improve its adaptation to a denture to improve its adaptation to the supporting mucosathe supporting mucosa..

Reline IndicationsReline Indications

Loss of retentionLoss of retention

InstabilityInstability

Food under dentureFood under denture

Abused mucosaAbused mucosa

Whenever the denture loses or has poor adaptation to the underlying tissues, while all other factors as occlusion, esthetics, centric relation, V.D.O. and denture base material are satisfactory.

Reline: General Reline: General ConsiderationsConsiderations

Optimal tissue healthOptimal tissue health

Reasonable CR/COReasonable CR/CO

Adequate vertical dimensionAdequate vertical dimension

Adequate peripheral extensionsAdequate peripheral extensions

Denture preparation:• Any undercuts are removed from the denture base.• Peripheral extensions are checked and adjusted.• Borders are reduced and squared to provide a definite edge for addition of new resin material.

Procedures:• Patient is instructed to leave his denture out of his mouth at least 48 hrs to allow for recovery of tissues and reduce irritation caused by ill-fitted denture.

• A hole is made in the palatal surface to allow escape of excess impression material. Slight reduction in the fitting surface may be done to create some space for the impression material.

• Border tracing & new impressions are made under centric occlusion to maintain occlusal relationship.

• The denture with impression material is boxed and poured into stone.

. The denture is flasked, and the old resin material is thoroughly cleaned and roughened.

. New acrylic resin material is packed, and the denture is cured in pressure curing unit containing water at 45°c for 20 min. to prevent porosity of new resin material and warpage of the old resin material (release of internal stresses).

. Finishing and polishing is done in the usual manner.

N.B.

When both upper and lower dentures need relining, lower denture should be completed first. The upper may be relined against a stable lower denture. The denture should be clinically remounted to perfect the occlusion.

Evaluate DenturesEvaluate Dentures

Is Reline Is Reline necessarynecessary????????

If after modifications, the “fit and If after modifications, the “fit and bite” seem improved, let the bite” seem improved, let the

patient try the denture for one patient try the denture for one week…if there is no week…if there is no

improvement, then relineimprovement, then reline..

Is reline NecessaryIs reline Necessary??

Irritation of Peripheral Borders

Overextension

Is reline NecessaryIs reline Necessary??

Overextended borders

Borders corrected

Is reline necessaryIs reline necessary??

Error in CO on one Error in CO on one side, will break side, will break the seal on the the seal on the

opposite sideopposite side

Is reline necessaryIs reline necessary??

Correct eccentric excursions

Diagnosis-Occlusal Diagnosis-Occlusal disharmonydisharmony

1.1. Loss of stability and retentionLoss of stability and retention

2.2. Irritation and inflammation on Irritation and inflammation on one sideone side

3.3. Teeth stained on one sideTeeth stained on one side

Reline Reline ContraindicationsContraindications

1.1. Worn out denturesWorn out dentures

2.2. Vertical dimension loss greater Vertical dimension loss greater than 7 mmthan 7 mm

3.3. Significant mucosal inflammationSignificant mucosal inflammation

4.4. Poor denture estheticsPoor denture esthetics

5.5. Denture related speech Denture related speech problemsproblems

ContraindicationsContraindications•Severe tooth wear

•Severe vertical overlap with tooth wear (posterior tooth concept)

•Severe occlusal wear (CD evaluation)

Pre-requisites for Pre-requisites for reliningrelining

Recognition of abused tissues, with superimposed candidiasis.

Initiate Tissue Initiate Tissue Recovery ProgramRecovery Program Intermittent hot and cold rinsesIntermittent hot and cold rinses Massage tissuesMassage tissues Relieve pressure areasRelieve pressure areas Correct faulty occlusions and denture Correct faulty occlusions and denture

bordersborders Minimize stress byMinimize stress by

– Soft dietSoft diet– Removal of denture at nightRemoval of denture at night

Use tissue conditionersUse tissue conditioners

Complete Denture Complete Denture ExamExam

Healthy TissuesHealthy Tissues!!!!

CUD RelineCUD Reline

1. Check extensions 2. Indicate amount of peripheral reduction required

3. Border Reduction 4. Tissue Conditioner preparation: Peripheral reduction + Tissue surface

CUD RelineCUD Reline

5. Border Molding Completed

6. Palatal surface vented after B. M.

7. Seat denture until wash comes through vents 8. Final Impression

CUD RelineCUD Reline

Incorrect seating. Incorrect seating. Improper plane of Improper plane of

orientationorientation::–Not contacting Not contacting

teethteeth–Excess materialExcess material–No ventsNo vents

Place ZnO washPlace ZnO washHave patient close Have patient close

in CRin CR..

CUD RelineCUD Reline

ZnO wash. Posterior palatal seal area using impression wax

Trim excess wax beyond anterior line

Reline final impression

Final Impression with PVS Final Impression with Rubber base

post palatal seal post palatal seal combinationcombination

Identify in Identify in impression, before impression, before

pouring it uppouring it up..

Identify on Identify on impression so impression so

technician can technician can scribe the sealscribe the seal

CLD RelineCLD Reline

Border molding completed

Complete Denture method-ZnO

Rubber Base Reline

RelineReline

Relined cast: Do not separate

Roughened border to blend

new acrylic with old. Won’t show

finishing line

After processing: Note junction line

RelineReline

Trimmed and polished

Delivery of RelineDelivery of Reline

Examine:•Peripheral extensions

Delivery of RelineDelivery of Reline

Pressure Pressure Indicator Paste Indicator Paste

(PIP)(PIP)Ask the patient to Ask the patient to

bite on cotton bite on cotton rolls for 5 minrolls for 5 min..

LABORATORY LABORATORY REMOUNTINGREMOUNTING

CLINICAL REMOUNTINGCLINICAL REMOUNTING

Perfection of occlusionPerfection of occlusion

Def: It is a process of readaptation of a denture to the underlying tissues by replacing the denture base material with a new one without changing its occlusal relation.

Rebasing of Complete Dentures

Indications:

When the existing denture base is unsatisfactory e.g. stained, crazed or porous.

Procedures:• An impression is made with the denture and a cast is obtained.

• An occlusal and incisal index of the teeth is made in plaster using Hooper duplicator The posts of the lower part of the duplicator are seated in the upper part to maintain the relationship of the casts to the plaster index.

• The denture with the impression material are removed from the cast.

• Artificial plastic teeth are sectioned from the denture and all base material around the teeth is removed. (porcelain teeth are removed by flaming)

• Teeth are placed and held in position in the index using sticky wax on the labial and buccal surface.

• A layer of base plate wax is placed over the ridge of the cast.

• The upper part of the duplicator is closed and denture teeth are waxed to the proper thickness and contour to the cast.

• The cast is removed, flasked and processed in the usual manner.

• After deflasking, the cast is reattached to the upper part of the duplicator to adjust any occlusal errors.

• Occlusion of rebased denture is further perfected by clinical remount.

THANK THANK YOUYOU