Anatomy and histology of the denture bearing area - Dentistry ...

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Muscles of facial expression which form modiolus • Buccinator muscle It arises from both jaws opposite the molar alveolar area and posteriorly from the pterygomandibular raphé. As the buccinator fibres run almost parallel to the denture border, they can slightly be displaced for additional retention. In this respect, it is the UNIQUE and ONLY muscle that can be used this way. Denture bearing area • Mental nerve This nerve emerges from the mental foramen near the apices of the lower premolars. In patients with extreme alveolar resorption, the nerve may lie on or near the crest of the alveolar ridge. Pain or paraesthesia may be experienced if the nerve is trapped by a denture base, usually by the fitting surface. • Massater muscle This muscle is the MOST powerful of the muscles which close the MANDIBLE. The lower denture periphery related to it should be shaped according to its structure so that displacement of the denture can be avoided when the muscle contracts. • Anterior fibres of temporalis These fibres are sometimes attached low down on the anterior border of the ramus as far as the attachment of the buccinator in the retromolar fossa. The contraction of these fibres may sometimes displace a lower denture. 2
• Retromolar pad Retromolar pad lies distal to the lower third molar and is composed of fibrous tissue and mucous glands. • Superior constrictor muscle This muscle originates from the pterygomandibular raphé with a small extension continuing on the lingual surface of the mandible to the posterior end of the mylohyoid line. • Genioglossus muscle and genial tubercle The genioglossus arises from the superior genial tubercles on the lingual surface of the mandible. When the tongue is protruded, this muscle may lift the lower denture. When the edentulous mandible is severely resorbed, the superior genial tubercle may project above the level of the alveolar ridge and the mucosa may become traumatised by a lower denture. Muscles limiting the extension of a lower denture • Lingually The posterior extension is limited by fibers from the superior constrictor muscle. Fibres from the palatoglossus also form a posterior limit. The depth of the lingual flange is governed by the mylohyoid. • Mylohyoid muscle It is a thin sheet of muscle and forms the floor of the mouth. Its linear origin from the mylohyoid line of the mandible continues posteriorly to the level of the third molar. • Sublingual salivary gland This gland rests on the mylohyoid muscle medial to the mandible. It is usually adjacent to the lower canine region. Its indentation is often seen on lower impressions Muscles limiting the extension of a lower denture • Anterior labial flange Orbicularis oris as far as the first premolar region. • Buccally Buccinator muscle • Retromolar pad Buccinator and its insertion into the pterygomandibular raphé. Upper jaw • Coronoid process Coronoid process lies lateral to the maxillary tuberosity. It may sometimes impinge on the buccal flange of a denture and cause pain or instability. • Hamular notch This notch is the junction of the maxillary tuberosity and hamular process. The periphery of a correctly extended denture should extend through these notches via the area of the fovea palatinae. 3
Page 1: Anatomy and histology of the dentur
Page 5 and 6: Muscles attachment changes with pro

Anatomy and histology of the denture bearing area - Dentistry ...

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