Terminology• Prosthodontics: the branch of dentistry that deals with the replacement missing dental ,oral and craniofacial structure.• Prosthesis: an artificial replacement of an absent part of the human body.
• Dentulous: A condition in which complete set of natural teeth are present in the mouth.
Edentulous :a condition in which themouth is without teeth it may be partiallyedentulous or completely edentulous.
Lips• Nasolabial Angle – Angle between columella of nose & philtrum of lip – Normally, approximately 90° as viewed in profile
• 4- Naso-labial sulcus: Naso- – Def.: it is a depression that extends from the ala of the nose in a downward and lateral direction to the corner of the mouth. – Prosthetic importance: it becomes more prominent with aging and teeth loss so should be restored by proper:- – vertical dimension - anterior teeth positioning - labial flange
• Mento-labial sulcus Mento- sulcus: – Def.: it is the sulcus between lower lip and chin. – Prosthetic importance: its curvature indicates the character of maxillo-mandibular relationship. Class II angle Class I angle Class III angle
• Modiolus: – Def.: this is located at the confluence of the buccinator and other facial muscles near the angle of the mouth. – Prosthetic importance: sunken cheeks appearance and droped angle observed by loss of maxillary teeth.
Residual ridge: It is the portion of the alveolar process and its soft tissue coverage that remains after extraction. the highest continuous surface of the ridge is called Crest of the ridgeResidual ridge is considered oneof the primary stress bearing area.
Maxillary tuberosity It is a prominent bulge located just behind and above the distal end of the maxillary ridgewell formed tuberosities offer wide coverage so enhancing support andretention of the denture.However extremely large onesneeds surgical correction.
Maxilla• Incisive Papilla – Landmark for setting of teeth
Maxilla• Hard Palate – Median Palatine Raphe (midline palatine suture) • A bony midline structure • May require relief when covered by a denture
Maxilla• Torus Palatinus – May require removal
Maxilla• “Hamular” Notch – Posterior border denture • Between the bony tuberosity and hamulus • “Soft displaceable tissue”, for comfort and retention
Maxilla• Soft Palate – Fovea Palatine • Bilateral indentations near midline of the soft palate • Close to the vibrating line
Maxilla• Soft Palate –Vibrating Line • Critical posterior border dentures • Junction of movable and immovable portions of the soft palate
Mandible• Ridge form – U-shape best – Non-moveable best – Advise patient if poor – Affects: • retention • stability
Mandible• Pear Shaped Pad(retromolar pad) – Soft pad containing glandular tissue – Pear shape, posterior border – Created from scarring after extractions
Mandible• External Oblique Ridge – Do not extend dentures to this ridge
Mandible• Buccal Shelf – Primary denture bearing area of mandibular denture – Between height of bridge & external oblique ridge – Resorbs more slowly
Mandible• Lingual Tori – Raised bony structures – May require relief when covered by a denture – Thin mucosa can ulcerate easily
Mandible• Mylohyoid Ridge – Origin of mylohyoid muscle which influences length of lingual flange – Can be prominent, and/or sharp, requiring relief
Mandible• Genial Tubercles – Attachment for the genioglossus muscle – Tubercles may be higher than the ridge with severe resorption
BORDER STRUCTURES THAT LIMITS THE PREPHERY OF THE DENTURE
Frena (singular = frenum)• Must be relieved to allow movement, without impingement• If prominent, adequate relief can weaken a denture• If too much relief, retention is lost• Check prominence intraorally
Lingual frenum Buccal frenum
Limiting structures of maxillary denture Labial frenum Labial vestibule Buccal frenum Buccal vestibule Hamular notchVibrating line of soft palate
Limiting structures of mandibular denture Labial frenum Buccal frenum Lingual frenum Buccal vestibule Lingual pouch Retromolar bad
• Retention :resistance to the dislodging forces along the path of placement.• Stability :to be firm, steady or constant to resist displacement by functional horizontal or rotational stresses.• Support :the foundation area on which a dental prosthesis rest. It is the resistance to the force toward the tissue.
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