Prosthetic IV. Removable dentures I. Removable dentures I. Removable partial dentures Complete denture Patient can remove the denture - Care for the denture: cleaning - These dentures can be anchored on the teeth or implants - The teeth can transfer the masticatory forces or be only for retention of the denture - Retention of complete denture – adhesion on mucosa Removable dentures I. lenka.roubalikova@tiscali.cz 4 Classification of pilots (abutment teeth) Pilots I. class Canines Molars (1st, 2nd) lenka.roubalikova@tiscali.cz 5 Classification of pilots (abutment teeth) Pilots II. st class Incisors - maxillary incosors, pemolars lenka.roubalikova@tiscali.cz 6 Classification of pilots (abutment teeth) Pilots III. class Mandibular incisors, third molars, all teethe with bad biological factor lenka.roubalikova@tiscali.cz 7 Biological factor ➢Caries ➢Pulp vitality ➢Level of the endodontic treatment ➢Level of the resorption of the alveolar bone ➢Periodontium ➢Relationship to antagonists ➢Relationship to neihgbour teeth lenka.roubalikova@tiscali.cz 8 Classification of defects Voldřich I. Class One or more teeth are missing Small gaps – 1 – 2 teeth Big gaps 3 – 4 teeth at most. This big gaps must be demarcated by pilot of the best quality. (canine, 1st or second molars – pilots of 1st class or their equivalents) Way of the transfer of masticatory forces ➢Tooth ➢Tooth and oral mucosa ➢Oral mucosa ➢Implants Tooth and/or oral mucosa/Implants bone lenka.roubalikova@tiscali.cz 10 Classification of defects Voldřich II. Class Reduced dental arch, thenlast tooth is the second molar. With gaps Without gaps Bilateral Unilateral lenka.roubalikova@tiscali.cz 11 Classification of defects Voldřich III. Class Individual teeth or small groups of teeth lenka.roubalikova@tiscali.cz 12 Classification of defects Voldřich IV. Class Edentulous dental arch Removable partial dentures Class I. Dental arch with gaps (interruptions) Teeth supported (borne) dentures Class II. Reduced (shortened) dental arch Teeth and tissue supported (borne) dentures Components Base –replaces missing part of alveol and supports arteficial teeth. Base (basis) Supports the supplied teeth and effects the transfer of occlusal stresses to the supporting oral structures. Different materials – metal framework + resin (attached to the metal framework) Or resin only Base Accuracy of adaptaion to the tissues with low volume change Dense, non irritating surface that is capable of receiving and maintaining a good finish Low thermal conductivity Low specific gravity Sufficient strength – resitance to fracture Easily kept clean Aesthetics acceptability Potential for future relining Low initial cost lenka.roubalikova@tiscali.cz 17 The materiál for base: Methylmetacrylate Components Elements of anchorage Clasps– casted clasps, wire clasps, combined clasps. Anchorage supporting bar Attachements Telescope crowns Clasps Surface retainers – they lie on the surface of teeth Arms – one, two or three arms Clasps One armed Clasps Two armed Clasps Three armed clasp Components Teeth – acrylic teeth - porcelain teeth Clasps One arm made of wire ➢Simple retainer, only in simply temporary prothesis. ➢It can damage the tooth because no stabilization (bracing) Clasps Two arms clasps One arm for retention (wire) One arm for stabilization against horizontal forces Clasps Three arms clasps One arm for retention (wire) One arm for stabilization (bracing) against horizontal forces On arm for transmission of occlusal forces Clasp made of wire and a cast part - combined Clasp completely cast Classification of the clasps ass to the material Clasps Three arms clasps One part for retention (going under the maximal convexity) One part for stabilization against horizontal forces (upon the maximal convexity) On arm for transmission of occlusal forces the rest) Clasp – three armed cast One part for retention (going under the maximal convexity) One part for stabilization against horizontal forces (upon the maximal convexity) On arm for transmission of occlusal forces (the rest) Rests Any unit of a partial denture that rests upon a tooth surface to provide vertical support to the denture is called a rest Upon the occlusal surface (premolar, molar) 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. Other elements of anchorage Anchorage supporting bar Attachements Telescope crowns Anchorage supporting bar Attachements Patrix – male part Matrix – female part Attachements on implants Telescope crowns Components Connectors - Major - Minor Connect the parts of denture Major connector Connect the parts of the prothesis - All other parts are directly or indirectly attached to it - Musí be rrgid – stresses may be effectively distributed over the entire are Mandibular major connector 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. Placed not on a convex surface of the abutment teeth but in embarasure Lingual plate Anterior palatal bar Posterior palatal bar Minor connector Palatal plate Lingual bar Removable dentures I. and II. Dentures with metal framework Removable dentures – classes Class I. Dental arch with gaps (interruptions) Teeth supported (borne) dentures Class II. Reduced (shortened) dental arch Teeth and tissue supported (borne) dentures Removable dentures – classes Class III. Single teeth Loss of the most important abutment teeth (big gaps – more than 4 teeth) Mostly tissue (borne) dentures, sometimes teeth supported additionally Class IV. Complete denture Tissue supported (borne) Class I and II dentures with the metal framework Class I. denture Components: Metal framework Base Clasps Arteficial teeth Class I and II dentures with the metal framework Lingual plate Class I and II dentures with the metal framework Anterior palatal bar Posterior palatal bar Minor connector 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: The bite template is necessary for The registration of the intermaxillary Relationship. It consist of the shellack base and the wax walls. Wax walls Shellack base Sequences of operation Registration of the intermaxillary relationship. The registrate Sequences of operation Preparation of the model for backup. All undercuts are blocked out Also the space under the future framework Using heated wax Sequences of operations Backup using the reversibile impression agar based material in a special flask Pouring of this impression with -the investing material – casting model Sequences of operations Fabrication of the wax pattern of the metal framework. Influx system 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. Arteficial teeth - acrylic 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 metal framework? On which model is the wax pattern of the framework made? What is the method of „lost wax“ ? 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. What is the purpose of the bite template? Which part does it consist of? Explain the term „investment“ .