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REVISION (1) B.M.C. **CHAPTER. (1) INTRODUCTION. Prosthetics. The art and science of supplying artificial replacement for missing parts of the human body. Prosthesis. An artificial replacement of an absent part of the human body. Prosthodontics (Prosthetic Dentistry).
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Prosthetics The art and science of supplying artificial replacement for missing parts of the human body. Prosthesis An artificial replacement of an absent part of the human body. Prosthodontics (Prosthetic Dentistry) It is the dental specialty pertaining to the diagnosis, treatment planning, rehabilitation & maintenance of the oral function, comfort, appearance and health of patients with clinical conditions associated with missing/deficient teeth &/or maxillofacial tissues using biocompatible substitute.
Components of complete denture 2 1 1- Denture base 2- Artificial teeth
Denture surfaces 1- Denture basal surface:
Objectives of complete denture 1-Restoration of the function ofmasticationto restore the normal digestive process 2- Appearance (esthetics) restoring the normal appearance of the face especially the lower third of the face.
3- Correction of speech defects ►Loss of teeth (especially anteriors)Speech Defects ►The artificial teeth should be placed in a position previously occupied by the natural teeth. 4- Preservation of the remaining tissues
Anatomical Landmarks In Relation To Complete Denture : Extra Oral Landmarks Inter pupillary line Ala Tragus Line Naso – Labial sulcus Modulus Labiomental sulcus
Inter pupillary line Anterior Occlusal Plane Determination Ala Tragus line Posterior Occlusal Plane Determination Naso – Labial sulcus Becomes deeper with age and with loss of teeth Modulus Become Flat With The Loss Of Teeth Labiomentalsulcus Classes of jaw relations
Intra Oral Landmarks Incisive Papilla Denture Bearing areas / Upper Incisive Papilla 1 . The incisive papilla is a thick part of the mucous membrane covering the incisive foramen. 2 . It is located at the anterior end of the median palatine raphae . 3 . The nasopalatine nerves and vessels pass through the incisive foramen to supply the anterior 2 / 3 of the palate. 4 . In some cases due to the excessive bone resorption, the papilla may lie on the crest of the ridge. 5 . The incisive papilla should be relieved to avoid pressure on the incisive nerves and vessels. CAUSING BURNING SENSATION IN THE ANT. 2/3 OF PALATE
Denture Bearing areas / Upper Palatine Rugae Raugae Area 1 . It is an irregularly shaped elevations of soft tissue extending laterally from the midline in the anterior part of the hard palate. 2 . It serves as one of stress bearing areas in the palate .
Denture Bearing areas / Upper Median Palatine Raphae Median Palatine Raphae 1 . The midline of the hard palate is covered by a thin layer of mucoperiostium , that covers the median palatine suture . 2 . That suture joins the right and the left halves of the hard palate. 3 . It is usually relieved to increase denture stability by preventing its rocking .
Denture Bearing areas / Upper Fovia Palatina Fovia Palatina 1 . It helps in the determination of the posterior border of the upper denture. 2 . The posterior border of the upper denture should be 2 mm posterior to the fovea Palatina .
To Continue ( Bearing Areas) Residual Alveolar Ridge Residual Alveolar Ridge 1 . It should be firm specially in the lower ridge . 2 . It covers the crest of the lower ridge. 3 . Its mobility may cause pressure symptoms under the lower denture. 4 . Also can affect denture stability .
To Continue ( Bearing Areas) Buttress Part Of Bone Buttress Part Of Bone 1 . It is formed of the lower portion of the zygomatic process of the maxilla (the area above the first molar teeth) . 2 . It provides excellent resistance to the vertical forces(Support).
To Continue ( Bearing Areas) Tuberosity Tuberosity 1 . It is important for retention and support of the upper denture against lateral movement. 2 . The denture should cover it , because it is one of stress bearing areas in the upper jaw .
To Continue ( Bearing Areas) Immovable Part of Soft Palate Immovable Part of Soft Palate 1 . The immovable part lies adjacent to the hard palate and the movable part lies more posterior. 2 . The posterior edge of the upper denture should end at the junction of these two parts .
Denture Limiting Structures (Upper) Labial Frenum Labial Frenum It must be relieved in the denture by making a V-shape notch in the labial flange opposite to its position .
Denture Limiting Structures (Upper) Labial Vestibule LabialVestibule 1 . It Is the reflection of the mucosa of the lip to the mucosa of the alveolar process in the labial vestibule. 2 . The denture in this area is in relation to the orbicularis oris and the superior incisive muscles . 3 . These muscles limit the thickness and the length of the labial flange of the denture.
Denture Limiting Structures (Upper) BuccalFrenum Buccal Frenum 1 . It is a fold of mucous membrane (tendon of the buccinator muscle) varies in size in number and in position . 2 . A notch is made in the denture flange opposite to its position to facilitate its functional movements.
Denture Limiting Structures (Upper) Buccal Vestibule Buccal Vestibule 1 . The denture in this area is related to buccinator muscle. 2 . Buccal flanges must extend in the buccal vestibule . 3 . Due to the horizontal direction of the fibers of this muscle; the contraction of this muscle will not displace the denture.
Denture Limiting Structures (Upper) Hamular Notch Hamular Notch 1 . It is one of the important landmarks for determination of the posterior limit of the upper denture . 2 . A straight line from hamular notch on one side to the other on the other side determines the posterior limit of the upper denture
Denture Limiting Structures (Upper) Vibrating Line ( Ah Line) Vibrating Line ( Ah Line) 1 . It separate the movable part from the immovable part of the soft palate. 2 . This line is 2mm posterior to the fovea palatine . 3 . This line determines the posterior end of the upper denture.
Denture Bearing and Limiting Structures (Lower) Retro Molar Bad Retro Molar pad 1 . It is a pear shaped area of mucous membrane at the posterior end of the mandibular ridge and anterior to the pterygomandibularraphae . 2 . It consists of mucous glands , temporal tendon , fibers of the buccinators and superior constrictor muscle . 3 . Lower denture should cover this area for retention and to cover the buccal shelf of bone.
Denture Bearing and Limiting Structures (Lower) Buccal Shelf Of Bone Buccal Shelf Of Bone 1 . The area that lies between the crest of the residual ridge and the external oblique ridge. 2 . It is the primary stress bearing area in the lower arch . 3 . It forms good support for the lower denture .
Denture Bearing and Limiting Structures (Lower) Buccal Vestibule Buccal Vestibule 1 . The denture in this area is related to the buccinator muscle . 2 . Its contraction does not displace the lower denture so flanges of the lower denture must extend in the buccal vestibule.
Denture Bearing and Limiting Structures (Lower) Buccal Frenum Buccal Frenum 1 . It is a fold of mucous membrane in the premolar area, movement of the lip and the cheek move the frenum . 2 . A notch is made in the lower denture to accommodate the frenum.
Denture Bearing and Limiting Structures (Lower) LabialFrenum Labial Vestibule Labial Frenum Labial Vestibule
Denture Bearing and Limiting Structures (Lower) Residual Ridge Residual Ridge
Denture Bearing and Limiting Structures (Lower) Lingual Pouch Lingual Pouch More posteriorly the lingual flanges are related to the lingual pouch with its boundaries which are : Posteriorly : The palatoglosssus muscle . Anteriorly : The Mylohyoid muscle. Medially : The tongue . Laterally : The medial aspect of the mandible.
Denture Bearing and Limiting Structures (Lower) Sublingual salivary gland area Sublingual salivary gland area The lingual flanges of the lower denture should not extend in this area because with excessive resorption of the mandible the gland may bulge superiorly above the body of the mandible.
Denture Bearing and Limiting Structures (Lower) Lingual Frenum Lingual Frenum 1 . More anteriorly a fold of mucous membrane attach the mucosa of the tongue to mucosa of the floor of the mouth 2 . It moves with the movement of the tongue so a notch is made to accommodate the frenum.
Types of Trays I- Stock trays II- Custom trays (Special, Individual trays)
The body and handle are designed to suit different mouths 1-Dentulous mouth cases . 2-Edentulous mouth cases . 3-Partially edentulous mouth cases.
Types of special trays 1- Shellac base plate special tray 2- Acrylic resin custom (special) trays: a- cold cured b- heat cured c- light cured Both heat and cold cured are used widely now. It is rigid and light in weight, not wrap in the mouth . 3- Cast or swaged metal tray 4- Vacuum formed plastic sheets It needs a pressure forming machine
Comparison between shellac and acrylic resin custom trays Self-cured acrylic resin special tray • Shellac base plate special tray • Low strength. 2. Easily distorted by load and temperature. 3. Improper adaptation to the cast 4. Easily constructed • Higher strength and rigidity. • Not distorted by temperature. • Well adapted • 4. Easily constructed
Tray can be 1- with a spacer 2- without a spacer
SHIM OR SPACER “ One thickness of modeling wax or shellac base plate adapted on the study cast under the special tray “
Impression Impression is a negative likeness or copy. Castis a positive copy
Preliminary (primary) impression Is defined as: a negative likeness made for the purpose of diagnosis, treatment planning, or fabrication of a special tray. Preliminary (study) castis defined as: a cast formed from a preliminary impression for use in diagnosis or the fabrication of a special tray.
Final (secondary) impression “The impression represents the completion of the registration of the surface or object. It is an impression which is used for making definitive (master) cast. “