lec 1 -3rd (١).pdf

INTRODUCTION TO REMOVABLE PARTIAL DENTURES 3rd Class Dr. Noor M. Shihab and definitions  Denture supporting structures: The tissues (teeth and/or residual ridges) that serves as the foundation for removable partial or complete dentures.  Diagnostic cast: A li...

INTRODUCTION TO REMOVABLE PARTIAL DENTURES 3rd Class Dr. Noor M. Shihab and definitions  Denture supporting structures: The tissues (teeth and/or residual ridges) that serves as the foundation for removable partial or complete dentures.  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.  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. 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).  Interim, or provisional denture: A fixed or removable dental prosthesis, or maxillofacial prosthesis designed to enhance esthetics and function for a limited period of time, after which it is to be replaced by a definitive dental or maxillofacial prosthesis.  Abutment: A tooth, a portion of a tooth, or that portion of a dental implant that serves to support and/or retain 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 cross sectional 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 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 and/or fixed dental prostheses oriented so as to contribute to the direction of the path of placement and removal of a removable partial denture, maxillofacial prosthesis, and overdenture. 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 prosthesis.  Treatment plan: The sequence of procedures planned for the treatment of a patient after diagnosis.  Nesbit prosthesis: Eponym for a unilateral removable partial denture that restores missing teeth on one side of the arch only, without a cross-arch major connector.  Cast trimming: it’s a process of cutting teeth away from cast in order to be replaced with artificial teeth.  Trimming of the cast must be done carefully to estimate as possible the shape of the residual ridge after teeth extraction. Final cast ridge must be similar to the couture of the foundation area after extraction. Usually teeth are trimmed by using a saw or disc bur sharp knife or wax knife may help. (In this step it must follow the rule of third to guide cast trimming). Steps of trimming are: