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 palatine raphea.Relief of the median 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 Addition of Material to the tissue side of a denture to improve its adaptation to the supporting mucosa.
Reline Indications Loss of retention Loss of retention Instability Instability Food under denture Food under denture Abused mucosa Abused 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 Considerations Optimal tissue health Optimal tissue health Reasonable CR/CO Reasonable CR/CO Adequate vertical dimension Adequate vertical dimension Adequate peripheral extensions Adequate 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.
Is Reline necessary???? If after modifications, the “ fit and bite ” seem improved, let the patient try the denture for one week … if there is no improvement, then reline.
Is reline Necessary? Irritation of Peripheral Borders Overextension
Is reline Necessary? Overextended borders Borders corrected
Is reline necessary? Error in CO on one side, will break the seal on the opposite side
Is reline necessary? Correct eccentric excursions
Diagnosis-Occlusal disharmony 1. Loss of stability and retention 2. Irritation and inflammation on one side 3. Teeth stained on one side
Reline Contraindications 1. Worn out dentures 2. Vertical dimension loss greater than 7 mm 3. Significant mucosal inflammation 4. Poor denture esthetics 5. Denture related speech problems
Contraindications Severe tooth wear Severe vertical overlap with tooth wear (posterior tooth concept) Severe occlusal wear (CD evaluation)
Pre-requisites for relining Recognition of abused tissues, with superimposed candidiasis.
Initiate Tissue Recovery Program Intermittent hot and cold rinses Intermittent hot and cold rinses Massage tissues Massage tissues Relieve pressure areas Relieve pressure areas Correct faulty occlusions and denture borders Correct faulty occlusions and denture borders Minimize stress by Minimize stress by –Soft diet –Removal of denture at night Use tissue conditioners Use tissue conditioners
CUD Reline 5. Border Molding Completed 6. Palatal surface vented after B. M. 7. Seat denture until wash comes through vents 8. Final Impression
CUD Reline Incorrect seating. Improper plane of orientation: Incorrect seating. Improper plane of orientation: –Not contacting teeth –Excess material –No vents Place ZnO wash Place ZnO wash Have patient close in CR. Have patient close in CR.
CUD Reline ZnO wash. Posterior palatal seal area using impression wax Trim excess wax beyond anterior line Reline final impression
Final Impression with PVSFinal Impression with Rubber base
post palatal seal combination Identify in impression, before pouring it up. Identify in impression, before pouring it up. Identify on impression so technician can scribe the seal Identify on impression so technician can scribe the seal
Reline Relined cast: Do not separate Roughened border to blend new acrylic with old. Won’t show finishing line After processing: Note junction line
Reline Trimmed and polished
Delivery of Reline Examine: Peripheral extensions
Delivery of Reline Pressure Indicator Paste (PIP) Pressure Indicator Paste (PIP) Ask the patient to bite on cotton rolls for 5 min. Ask the patient to bite on cotton rolls for 5 min.
Perfection 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.