Lect. 1 P.D.pdf

Lecture 1: Prosthodontics INTRODUCTION Prosthetics: The art and science of supplying artificial replacements for missing parts of the human body. Prosthodontics (Prosthetics dentistry): Is the dental specialty that deals with the diagnosis, treatment planning, rehabilitation and maintenance of th...

Lecture 1: Prosthodontics INTRODUCTION Prosthetics: The art and science of supplying artificial replacements for missing parts of the human body. Prosthodontics (Prosthetics dentistry): Is the dental specialty that deals with the diagnosis, treatment planning, rehabilitation and maintenance of the oral function, comfort, appearance and health of patients with clinical conditions associated with missing or deficient teeth and/ or maxillofacial tissues using biocompatible substitutes. Prosthesis: An artificial replacement of an absent part of the human body. Dental prosthesis: An artificial replacement of one or more teeth( up to the entire dentition in either arch) and associated dento / alveolar structures. Dentulous:. Edentulous Definitions 1-partial denture : a removable dental prosthesis or a fixed dental prosthesis that restores one or more but not all of the natural teeth and/or associated parts and may be supported in part or whole by natural teeth, dental implant, supported crowns, dental implant abutment(s), or other fixed dental prostheses and/or the oral mucosa Or Partial Dentures: A removable partial denture or a fixed partial denture that restores a partially edentulous arch; (a partial denture can be described as a removable partial denture or a fixed partial denture based on the patient’s capability to remove or not remove the prosthesis, respectively). 2-Removable partial denture: A partial denture that can be removed and replaced in the mouth by the patient.A partial denture being constructed from cobalt chromium alloy and considered to be as a permanent treatment  Objectives of removable partial denture treatment: 1. Restore esthetic (especially for anterior teeth). 2. Restore function (phonetic and mastication) for proper speech, proper occlusion and proper food mastication. 3.To prevent apposing teeth extrusion or migration and tilting of adjacent teeth. 4.To fill empty space or spaces. 5. Prevent disease atrophy by a form of stimulation to the underlying tissue and ridge. 6. For proper muscular balance. 7. To restore the psychological status of the patient. Causes of teeth loss: 1. Caries (main cause in a young people below 35 years). 2. Periodontal diseases (main cause in old people above 35 years). 3. Trauma or accident (such as receiving a blow or falling down on them). 4. Congenital missing teeth.  Indications for removable partial denture 1. Distal extension situations (free end situation). 2. Long span tooth-bounded edentulous area. 3. Need for cross-arch (bilateral) stabilization. 4. Excessive loss of the residual ridge. 5. Unusually sound abutment teeth. 6. If the prognosis of remaining teeth is questionable or reduced periodontal support of remaining teeth (these teeth cannot support fixed prostheses). 7. After recent extraction (need immediate replacement of extracted teeth). 8. Patient younger than 18 years old. 9. Economic consideration. II. Fixed partial denture: Any dental prosthesis that is luted, screwed, or mechanically attached or otherwise securely retained to natural teeth, tooth roots, and/or dental implants/abutments that furnish the primary support for the dental prosthesis and restoring teeth in a partially edentulous arch; it cannot be removed by the patient. Indications for fixed partial denture: 1. Unilateral bounded edentulous short span. 2. Class IV Kennedy classification with normal loss of bone. 3. Modification area located anteriorly with Class I or with Class II Kennedy classification for simplifies the design of removable partial denture. III. Dental implant therapy: A prosthetic device made of alloplastic material(s) implanted into the oral tissues beneath the mucosal and/or periosteal layer and on or within the bone to provide retention and support for a fixed or removable dental prosthesis. The dental implants are considered adjuncts in fixed and removable therapy. However, not all patients are candidates for dental implant therapy. Contraindications for dental implant therapy 1. Unfavorable regional anatomy. 2. Uncontrolled systemic disease. 3. Extreme surgical risk. 4. High-dose head and neck radiation. terminology and definitions Diagnostic cast: A life-size reproduction of a part or parts of the oral cavity and/or facial structures for the purpose of study and treatment planning. Denture supporting structures: The tissues (teeth and/or residual ridges) that serve as the foundation for removable partial or complete dentures. Support: The foundation area on which a dental prosthesis rests; with respect to dental prostheses, the resistance to forces directed toward the basal tissue or underlying structures. Stability: The quality of a complete or removable partial denture to be firm, steady, or constant, to resist displacement by functional horizontal or rotational stresses. Retention: That quality inherent in the dental prosthesis acting to resist the forces of dislodgment along the path of placement. (e. g., the force of gravity, the adhesiveness of foods, or the forces associated with the opening of the jaws). Support, stability, and retention become more meaningful when they are thought of in terms of providing resistance to movement of a removable partial denture. Interim, or provisional, denture: A fixed or removable dental prosthesis, or maxillofacial prosthesis designed to enhance esthetics, stabilization, and/or function for a limited period of time, after which it is to be replaced by a definitive dental or maxillofacial prosthesis; often such prostheses are used to assist in determination of the therapeutic effectiveness of a specific treatment plan or the form and function of the planned definitive prosthesis. A denture used for a short period of time to provide mastication ,esthetic , occlusal support , and conditioning of the patient to accept the final prosthesis and it is mostly a P.D made of acrylic resin Abutment: A tooth, a portion of a tooth, or that portion of a dental implant that serves to support and/or retain a prosthesis.. Height of contour: A line encircling a tooth and designating its greatest circumference at a selected axial position determined by a dental surveyor Undercut: The portion of the surface of an object that is below the height of contour in relationship to the path of placement. When used in reference to an abutment tooth, is that portion of a tooth that lies between the height of contour and the gingiva. When it is used in reference to other oral structures; the contour of a crosssectional portion of a residual ridge or dental arch that prevents the insertion of a dental prosthesis. The angle of gingival (cervical) convergence: The angle of gingival convergence is located apical to the height of contour on the abutment tooth; it can be identified by viewing the angle formed by the tooth surface gingival to the survey line and the analyzing rod or undercut gauge of a surveyor as it contacts the height of contour. Path of insertion (placement): The specific direction in which a prosthesis is placed on the residual alveolar ridge, abutment teeth, dental implant abutment(s), or attachments. Guiding planes: Two or more vertically parallel surfaces on abutment teeth so as to contribute to the direction of the path of placement and removal of a removable partial denture, maxillofacial prosthesis, and over denture. Guiding plane surfaces are parallel to the path of the placement (insertion) and parallel to each other; preferably these surfaces are made parallel to the long axes of abutment teeth.  Bounded edentulous area: It is an edentulous area that is bounded and supported by natural teeth at both ends. Free-end edentulous area: It is an edentulous area that is bounded and supported by natural teeth at one end. Extension base or free end extension RPD: It is a removable partial denture that is supported and retained by natural teeth only at one end of the denture base segment and in which a portion of the functional load is carried by the residual ridge, it is tooth - tissue - supported RPD.  Fulcrum line of rotation of a removable partial denture: A theoretical line around which the RPD tends to rotate. Saddle or denture bases: The part of a denture that rests on the foundation tissues and to which teeth are attached. Basal seat or denture foundation area: The oral anatomy available to support a denture. Retainer: Any type of device used for the stabilization or retention of a prosthesis. Treatment plan: The sequence of procedures planned for the treatment of a patient after diagnosis. Nesbit prosthesis: indication for a unilateral removable partial denture that restores missing teeth on one side of the arch only, without a cross-arch major connector. Alternative to RPD treatment choices: 1-No treatment. 2-Fixed partial denture. 3-Implant supported prosthesis 4-Complete denture