Partial Denture FAYAD

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  • 2010

    MOSTAFA FAYAD

    Assistant Lecture of

    Removable Prosthodontic

    PARTIAL DENTURE THEORYAND PRACTICE

  • OBJECTIVES AND CLASSIFICATION

    Mostafa Fayad 1

    OBJECTIVES AND CLASSIFICATION OF PARTIAL DENTURES

    TERMINOLOGY

    Prosthesis: Is an artificial replacement of an absent part of the human body.

    Prosthetics: The art and science of supplying an artificial replacement for

    missing parts of the human body.

    Appliance used only for device worn by patient in course of treatment. e.g.

    orthodontic appliance and splint

    Prosthodontics: The branch of dentistry pertaining to the restoration and

    maintenance of oral functions, comfort, appearance, and health of the patient

    by the restoration of natural teeth and/or the replacement of missing teeth

    and contiguous oral and maxillofacial tissue with an artificial substitute.

    Dentulous Patients: Patients having a complete set of natural teeth.

    Edentulous Patients: Patients having all their teeth missing.

    Partially Edentulous Patient: Patients having one or more but not their entire

    natural teeth missing.

    Removable Partial Denture (RPD): An appliance that restores one or more but

    not all of the missing natural teeth and associated oral structures for partially

    edentulous patients.

    Abutment: A tooth, a portion of a tooth, or that portion of a dental

    implant that serves to support and/or retain prosthesis.

    Free End Edentulous Area (Distal extension edentulous area): An edentulous

    area, which has an abutment tooth on one side only.

    Bounded Edentulous Area: An edentulous area, which has an abutment tooth on each end.

    Dental cast: a positive life size reproduction of a part or parts of the oral

    cavity.

    The word cast is preferable than word model which used only for

    demonstration

  • OBJECTIVES AND CLASSIFICATION

    Mostafa Fayad 2

    Andrews Bridge

    The combination of a fixed dental prosthesis incorporating a bar with a

    removable dental prosthesis that replaces teeth with the bar area, usually

    used for edentulous anterior spaces. The vertical walls of the bar may

    provide retention for the removable component. By James Andrews.

    Gillett Bridge

    Eponym for a partial removable dental prosthesis utilizing a Gillett clasp

    system, which was composed of an occlusal rest notched deeply into the

    occlusal axial surface with a gingivally placed groove and a circumferential

    clasp for retention. The occlusal rest was custom made in a cast restoration.

    MORA Device

    Acronym for mandibular orthopedic repositioning appliance, a type

    of removable dental prosthesis with a modification to the occlusal surfaces

    used with the goal of repositioning.

    Angle of Gingival Convergence

    According to Schneider, 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 surfaces gingival to the survey line

    and the analyzing rod or undercut gauge in a surveyor as it contacts the

    height of contour.

    Continuous Gum Denture

    An artificial denture consisting of porcelain teeth and tinted porcelain

    denture base material fused to a platinum base.

    Fulcrum Line

    It is an imaginary line, connecting occlusal rests, around which a partial

    removable dental prosthesis tend to rotate under masticatory forces. The

    determinants for the fulcrum line are usually the cross arch occlusal rests

    located adjacent to the tissue borne components.

    Semi precision Rest

    A rigid metallic extension of a fixed or removable dental prosthesis that

    fits into an intracoronal preparation in a cast restoration.

  • OBJECTIVES AND CLASSIFICATION

    Mostafa Fayad 3

    Nesbit Prosthesis

    Eponym for a unilateral partial removable dental prosthesis design, that

    De. Nesbit introduced in 1918.

    Resilient Attachments

    An attachment designed to give a tooth borne/soft tissue borne

    removable dental prosthesis sufficient mechanical flexion, to withstand the

    variations in seating of the prosthesis due to deformation of the mucosa and

    underlying tissues without placing excessive stress on the abutments.

    CONSEQUENCES OF TOOTH LOSS

    1- A loss of ridge volumeboth height and widthcan be expected

    Bone loss is greater in the mandible than the maxilla, more pronounced

    posteriorly than anteriorly, and it produces a broader mandibular arch while

    constricting the maxillary arch.

    2- Alteration in the oral mucosa

    The attached gingiva of the alveolar bone can be replaced with less

    keratinized oral mucosa, which is more readily traumatized.

    3- Aesthetic impact

    Facial features can change Secondary to altered lip support and/or

    reduced facial height as a result of a reduction in occlusal vertical dimension.

    4- Reduction in masticatory efficiency

    It is the ability to reduce food to a certain size in a given time frame. It

    has been shown that there is a strong correlation between masticatory

    efficiency and the number of occluding teeth in dentate individuals.

    5.T.M.J.dysfunction

    6. Tipping, migration, rotation and superimposition of remaining teeth.

    7.Altered speech

  • OBJECTIVES AND CLASSIFICATION

    Mostafa Fayad 4

    Partial Dentures:

    Partial dentures are appliances restoring one or more but not the whole

    set of natural teeth . These Appliances maybe in form of:

    I- Fixed partial prosthesis ( bridge ):

    An appliance which restores one or more missing teeth it is permanently

    cemented to the neighboring natural teeth and cannot be removed by the

    patient.

    II- Removable partial prosthesis:

    An appliance which restores missing teeth and the associated oral

    structures for a partially edentulous patient " it can be removed by the patient .

    Removable partial dentures may restore :

    (a) Bounded edentulous area : which has an abutment tooth on each end.

    (b) Free end edentulous area : which has an abutment tooth on one side

    only . Partial dentures restoring free end cases are called distal- extension

    partial dentures.

    III- Partial over dentures : Partial over dentures are removable partial

    dentures that are constructed to overly and gain additional support

    from either :

    Natural teeth that are reduced in height and contour or : Implants inserted in the edentulous areas .

    IV- Removable partial Dentures for Maxillo facial Defects :

    These are removable prostheses restoring tissue defects which are

    either developmentally or traumatically acquired. They are usually

    retained by clasps on the remaining natural teeth.

  • OBJECTIVES AND CLASSIFICATION

    Mostafa Fayad 5

    Types of removable partial dentures :

    ( 1 ) Unilateral partial dentures : Partial dentures which restore teeth on one

    side of the arch without being extended to the opposite side

    ( 2 ) Bilateral partial dentures : partial dentures restoring missing teeth and

    extended on both sides of dental arch .

    According to retention to natural teeth

    a- Extra coronal retention

    b- Intracranial retention

    According to material

    -Metallic - acrylic -flexible

    OBJECTIVES OF REMOVABLE PARTIAL DENTURES

    1- Preservation of the Remaining Tissues:

    The primary purpose of RPD is the preservation of the health of the remaining

    tissues.

    A- Preservation of the health of the remaining teeth.

    The loss of teeth leads to migration, tilting or drifting of the

    remaining natural teeth into the edentulous spaces (Fig.1-3), such

    movements leads to unequal distribution of load on the remaining

    teeth. In addition to food impaction in the interstitial spaces leading to

    caries and /or gingivitis.

    B- Prevention of muscles and TMJ Dysfunction.

    Absence or movements of posterior teeth may cause:

    A- Changes in the pattern of mandibular closure (Fig.1-4).

    B- Change in the vertical and horizontal relations of the

    mandible and maxilla. Consequently muscles and TMJ Dysfunction

    may arise.

  • OBJECTIVES AND CLASSIFICATION

    Mostafa Fayad 6

    C-Preservation of the residual ridge.

    By preventing rapid bone resorption which may happen due to

    lack of function.

    D-Preservation of the tongue contour and space.

    2 Restore the Continuity of the Dental Arch to Improve Masticatory

    Function:

    A reduction of the number of teeth leads to a decrease in the chewing

    efficiency and greater effort on the digestive organs leading to digestive

    disorders, accordingly replacing lost teeth will greatly improve the chewing

    capability of the patients, distribute the load over the entire arch and improve

    the balance over the whole masticatory system.

    3- Improvement of Esthetics, and Providing Support to the Paraoral

    Muscles, Lips and Cheeks:

    Teeth and the alveolar ridge give support to the musculature of the lips

    and cheeks. Non-replacement of the missing teeth gives the patient a senile

    appearance characterized by nose-chin approximation and wrinkles around

    the lips. Missing teeth can be replaced with predictable results using partial

    denture.

    4- Restoration of Impaired speech:

    Anterior teeth play an essential role in phonetics, particularly in the

    production of labio and linguo-dental sound. Loss