Fixed Prosthodontics Lectures (TIU 2008) PDF

Fixed Prosthodontics Lecture No:1 Introduction Indications And Contraindications of FPD Lecturer: Dr.Lana Bahram Khidher BDS,Ph.D in Prosthodontic Advantage of Replacing Missing Teeth 1. Appearance 2. Ability to eat 3. Speech 4. Periodontal splinting 5. A feeling of completeness 6. Orthodontic r...

Fixed Prosthodontics Lecture No:1 Introduction Indications And Contraindications of FPD Lecturer: Dr.Lana Bahram Khidher BDS,Ph.D in Prosthodontic Advantage of Replacing Missing Teeth 1. Appearance 2. Ability to eat 3. Speech 4. Periodontal splinting 5. A feeling of completeness 6. Orthodontic retention 7. Restoring occlusal vertical dimension 8. Restore function and mastication. 9. Restore esthetics. 10. Maintain health and integrity of dental arch. 11. Support the treatment of the problem related to TMJ. 12. Occlusal stability Disadvantage Of Replacing Missing Teeth 1. Damage to tooth and pulp 2. Secondary caries 3. Failures 4. Effects on the periodontium 5. Cost and discomfort. Indication For FPD A Fixed Partial Denture Is Preferred For The Following Situations: 1. Short span edentulous arches. 2. Presence of sound teeth that can offer sufficient support adjacent to the edentulous space. 3. Cases with ridge resorption where a removable partial denture cannot be stable or retentive. 4. Patient’s preference. 5. Mentally compromised and physically handicapped patients who cannot maintain the removable prosthesis. 6. The patient has the skills and motivations to maintain good oral hygiene Contraindication for FPD Fixed partial dentures are generally avoided in the following conditions: 1. Large amount of bone loss as in trauma. 2. Very young patients where teeth have large pulp chambers. 3. Presence of periodontal compromised abutments. 4. Long span edentulous spaces. 5. Bilateral edentulous spaces, which require cross arch stabilization. 6. Medically compromised patients( e.g. leukemia, hypertension). 7. Very old patient. 8. Congenitally malformed teeth, which do not have adequate tooth structure to offer support 9. Mentally sensitive patient who cannot cooperate with invasive treatment procedures. Crowns Crown: it is a fixed extra-coronal restoration that restores missing tooth structure by surrounding most or all the remaining structure with material such as cast metal, ceramic, or a combination of materials such as metal and ceramic. Types of crowns Full Veneer Crown: is an extra coronal restoration that involves all of the surfaces of clinical crown of the tooth. Partial veneer crown: is an extracoronal restoration that cover some of the tooth crown and leaving the other intact such as (3\4)three –quarter crown, 7/8 crown, pin ledge and others. • Laminate veneers (type of partial veneer): It is a conservative method of restoring the appearance of discolored, pitted, or fractured anterior teeth. It consists of bonding thin ceramic laminates onto the labial surfaces of affected teeth. WHAT IS THE DIFFERENCE BETWEEN LAMINATE AND LUMINEER????? • Complete replacement (Post crown): It replaces the natural crown entirely. This type of crown retains itself by means of a dowel (post) extended inside the root canal space of the tooth such as a post crown.  An abutment is a tooth to which a bridge (or partial denture) is attached.  A retainer is a crown or other restoration that is cemented to the abutment. The terms ‘retainer’ and ‘abutment’ should not be confused or used interchangeably.  A pontic is an artificial tooth as part of a bridge.  A span is the space between natural teeth that is to be filled by the bridge.  A pier is an abutment tooth standing between and supporting two pontics, each pontic being attached to a further abutment tooth.  A unit, when applied to bridgework, means either a retainer or a pontic. A bridge with two retainers and one pontic would therefore be a three-unit bridge.  A connector (or joint) connects a pontic to a retainer, or two retainers to each other. Connectors may either be fixed or allow some movement between the components that they join. COMPONENT OF THE BRIDGE Bridges Bridge (Fixed Partial Denture): is an appliance replacing one or more teeth that cannot be removed by the patient. Classification of fixed partial dentures Generally Bridges According To : The Location Of The Edentulous Space 1. Posterior: Fixed partial denture confined to the posterior region, e.g. replacement of missing first molar. 2. Anterior: Fixed partial denture confined to the anterior region, e.g.replacement of missing central incisors. 3. Combination: Fixed partial denture extending both anteriorly and posteriorly, e.g. replacement of single/multiple teeth involving the turn of the arch, as in cases of replacement of missing canine,premolars. Location of abutment 1. Conventional: Abutment is located adjacent to the edentulous space and pontic is supported on both sides. This is the design for majority of fixed partial dentures. 2. Cantilever: Abutment is located adjacent to edentulous space but pontic is supported on one side only. 3. Spring cantilever: Abutment is not located adjacent to edentulous space and pontic receives support from one side only. A posterior abutment, generally premolar, is used to replace an anterior tooth and abar is used to connect the abutment and pontic. Types of connector 1. Fixed-fixed: Connectors on both sides of the pontic are rigid with no scope for any movement. 2. Fixed-movable: One of the connectors of the FPD assembly is non-rigid and is made of a precision or semiprecision attachment which allows some vertical movement This is normally indicated in case of a pier abutment, tilted abutments or periodontally weak abutments. 3. Fixed-removable: This prosthesis was developed by Dr James Andrews and is called ‘Andrews Bridge Type of materials used 1. All metal: These are used only to replace posterior teeth as they are not aesthetic. 2. Metal ceramic: These are also termed as ‘porcelain fused to metal’(PFM) crowns/retainers. These may be of two types:(i) Metal with complete ceramic coverage: In this there is a core of metal which fits on the abutment and is completely covered by ceramic both facially and lingually/palatally (ii) Metal with ceramic facing: In this restoration,though all the surfaces are formed by metal, ceramic covers the metal in the labial/buccal surface alone 3. All ceramic: These are fabricated using only ceramics with no metal component. They are also called ‘metal- free ceramic’ restorations 4. Metal with resin facings: This is similar to metal with ceramic facings except that instead of ceramic, acrylic or composite resin is used. 5. All acrylic, composite and fibre-reinforced composite: These are only used as provisional restorations. Comparison of the Bridge with Removable Partial Denture Fixed Prosthodontics Lecture No:2 Component of fixed partial denture Lecturer: Dr.Lana Bahram Khidher BDS,Ph.D in Prosthodontic COMPONENT OF THE BRIDGE Retainer: The part of a fixed dental prosthesis that unites the abutment(s) to the remainder of the restoration . Pontic: An artificial tooth on a fixed dental prosthesis that replaces a missing natural tooth, restores its function, and usually fills the space previously occupied by the clinical crown. Connector: The portion of a fixed dental prosthesis that unites the retainer(s) and pontic(s) Retainers are divided into two types 1. Major retainers (Full veneer crown) These retainers cover all the five surfaces of the abutment. They are fabricated like a cap and are usually indicated for extensively damaged teeth. They are the most retentive and ideal retainers because their design can resist masticatory forces in all directions. 2. Minor retainers (Partial veneer crown) A minor retainer may be a partial crown, or a two- or three-surface inlay without full occlusal protection, Minimal-preparation minor retainers are also used for minimal preparation bridges (resin bonded bridge) where the occlusion is favorable. Major or minor? all fixed-fixed, cantilever and spring cantilever bridges have only major retainers. Fixed-movable bridges have a major retainer at one end of the pontic and a minor retainer (carrying the movable joint) at the other. • The criteria for selecting a particular retainer will include:  Alignment of abutment teeth and retention  Appearance  Condition of abutment teeth  Conservation of tooth tissue  Occlusion  Cost  Alignment of abutment teeth and retention: • When the abutment teeth are less parallel to each path of insertion:  They could not be made independently retentive without one or other of the teeth being devitalized. This is sometimes necessary, but it is a very destructive approach.  The solution will usually be to employ a minimal preparation bridge or a design other than fixed-fixed so that the teeth do not have to be prepared parallel to each other.  When it is necessary to reduce a retentive feature, for example to over-taper a preparation to provide a single path of insertion with another preparation, it is advisable to add some further retentive feature such as grooves or a pin. Appearance: In some cases a complete crown will have a better appearance, in some a partial crown, and in others a minimal-preparation retainer. Condition of abutment teeth: Frequently a minimal-preparation or partial crown retainer cannot be used because of the presence of caries or large restorations involving the buccal surface, or because of the loss of the buccal surface from trauma or other cause. In these cases a complete crown retainer is chosen. Conservation of tooth tissue:  Buccal/facial surface should be conserved. Therefore, Partial veneer crowns are more conservative than full crowns. However, if there are sound indications for a complete crown, the operator should not allow his or her clinical judgments to be influenced by an overprotective attitude to dental enamel.  All ceramic crowns are the least conservative.  Occlusion: In some cases the abutment teeth are sound but there is insufficient space for a minimal-preparation retainer. The choice therefore is between creating space by reducing the opposing teeth, moving the abutment teeth orthodontically or a combination of these approaches. If none of these methods are acceptable then a conventional retainer will be necessary.  Cost: Partial crowns and complete metal crowns may be less expensive than metal-ceramic crowns, minimal-preparation retainers are the least expensive, and expensive. All ceramic crowns are the most Connector Pontics Pontic is the artificial tooth replacing the missing natural tooth. The name is derived from the Latin word pons meaning bridge. Following are the ideal requirements of a pontic: 1. Restore function of the replaced tooth. 2. Provide aesthetics and comfort. 3. Should be biologically acceptable. 4. Permit effective oral hygiene. 5. Preserve the underlying residual ridge and mucosa. 6. Have adequate strength to withstand occlusal forces. • Depending on the amount of contact the pontic makes with the underlying mucosa it is classified into the following types: 1.With mucosal contact Advantage……….The emergence profile of a pontic simulates the adjacent natural tooth; thus, it is aesthetically superior. Disadvantages……..The gingival surface of the pontic is not accessible by the patient, making it difficult to clean. As the gingival surface of the pontic is in contact with the ridge it may sometimes cause tissue inflammation. 2. Without mucosal contact (hygienic pontic) Advantage • Good access for the oral hygiene. Disadvantage • Poor aesthetics. Indications • Knife-edged posterior ridges. • Molars that do not require much aesthetic attention. Contraindications • Broad residual edentulous ridge. • Esthetic zone