Prosthetic IV.
Removable dentures I.
Classification
□ Class I. Dental arch with gaps (interruptions) interruptions
n Tooth supported (borne) dentures
□ Class II. Reduced (shortened) shortened ) dental arch
Way of the transfer of masticatory
forces
■ Tooth
□ Tooth and oral mucosa n Oral mucosa
□ Tooth and and/or oral mucosa
Bone
Components
Base
a Replaces missing part of alveol
■ Supports the supplied teeth and effects the transfer of occlusal stresses to the supporting oral structures
n structures.
Different materials -attached to the metal framework metal framework or resin only
Base must have
Accuracy of adaptaion to the tissues with low volume change
Dense non irritating surface that is capable of receiving and maintaining a good finish
Thermal conductivity
Low specific gravity
Sufficient strength - resitance to fracture Easily kept clean Aesthetics acceptability Potential for future relining Low initial cost
Components
□ Elements of anchorage
■ Clasps
casted clasps, wire clasps, combined clasps
□ Anchorage supporting bar
■ Attachements
Telescope crowns
Cast clasp
n Surface retainers they lie on the surface of teeth □ Arms
two or three arms
Clasps
□ One arm made of wire
□ Simple
□ retainer retainer, only in simply temporary 11 prothesis prothesis.
□ It can damage the tooth because no n stabilization (bracing)
Clasps
■ Two arms clasps One arm for retention (wire) wire
n One arm for stabilization against horizontal forces
Clasps
□ Three arms clasps One arm for retention (wire)
n One arm for stabilization (bracing) against horizontal forces
n One arm for transmission of occlusal forces
Clasps
□ Three arms clasps One part for retention ( n convexity)
J (convexity) upon the maximal convexity going under the maximal convexity One part for stabilization against horizontal forces
J On arm for transmission of occlusal forces the rest)
Rests
□ Any unit of a partial denture that rests upon the tooth surface to provide vertical support to the denture is called a rest
□ Upon the occlusal surface (premolar and moplar)
■ Upon the lingual surface (prepared) of anterior teeth
■
Rests
□ Transmitted forces parallel to the long axis of the tooth will prevent movement in a cervical direction
Connectors
□ Connectors connect the parts of denture
□ Major 11 Minor
Major connector
□ Connect the parts of the prothesis
n - All other parts are directly or indirectly attached to it
□ - Must be rigid - stresses may be effectively distributed over the entire area
Mandibular major connector
n Lingual bar
□ Lingual plate ( continouos bar retainer and lingual bar)
Maxillary major connector
■ Anterior and posterior palatal bar
■ U- shaped palatal connector □ Palatal plate type connector
Minor connectors
□ Arising from the major connector - join the major connector with other parts of the denture
n Placed not on a convex surface of the abutment teeth but in embarasure
Class I and II dentures with the metal framework
Class I and II dentures with the metal framework
Class I and II dentures with the metal framework
Sequences of operations Taking impressions (alginate.		
		Both jaws always !
		
Sequences of operations
Pouring - gypsum models.
Fabrication of the individual impression tray
if necessary.
If not, fabrication of the bite template:
Wax walls
Shellack base
The bite template is necessary for The registration of the intermaxillary Relationship.
It consist of the shellack base and the wax walls.
Sequences of operation
Registration of the intermaxillary relationship.
The registrate
Sequences of operation
□ Preparation of the model for backup.
Sequences of operations
□ Backup using the reversibile impression agar based material in a special flask
a Pouring of this impression with -the investing material - casting model
Sequences of operations
Fabrication of the wax pattern of the metal framework. /
Sequences of operations □ Investment with the same investing material -a special flask.		
		The wax is burnt out and the form is heated in a special oven. After that the casting process is performed using a special casting machine.
Sequences of operation
After casting and cooling the framework is taken out, the inflow system must be cut off.
Sequences of operation
□ The cast is grinded, polished and adapted on the former gypsum model
The final framework is tried out
Sequences of operation
□ The arteficial teeth will be applied acc. to intermaxillary registrate in articulator.
Sequences of operation
After trying out of the denture with wax base and teeth the denture is completed
The framework with the wax pattern of the base and teeth has been put into a flask, the wax has removed and replaced with a resin dought. The resin base is polymerized using heating.
Sequences of operation
The denture is finished, polished and tried in.
Feedback
□ For which classes of removable dentures is necessary to fabricate the framework?
n On which model is the wax pattern of the framework made?
□ What is the lost wax" method ?
Feedback
□ Which parts does the partial removable denture consist of?
□ Describe the sequences of operations of these dentures. Explain the main difference between class I. and II. removable dentures.
n What is the purpose of the bite template? Which part does it consist of?
■ Explain the term Jnvestment".