Relationship of the External Surface and Orofacial Musculature

By Dr.Swathi Pai on Tuesday 6 January 2009 with 0 comments



A. Influence of orofacial musculature: The basic geometric design of the denture base should be triangular. To direct a seating action on the mandibular denture, the tongue should rest against a lingual flange, inclined medially away from the mandible and somewhat concave. The degree of inclination depends on the balance of the muscular forces of the tongue as opposed to the mylohyoid and superior constrictor muscles. Generally, the buccal and labial flanges of the maxillary and mandibular dentures should be concave to permit positive seating by the cheeks and lips. The primary muscles of the lips and cheeks are the orbicularis oris and buccinator muscle, respectively.

B. Importance of modiolus: The modiolus or tendinous node is an anatomic landmark near the corner of the mouth that is formed by the intersection of several muscles of the cheeks and lips. These include the orbicularis oris, buccinator, caninus, triangularis, and zygomaticus muscles. None of these muscles have more than one bony attachment, so they depend on the modiolus for isometric contractions. The denture must be designed as to permit the modiolus to function freely.

C. Techniques: Neutral zone- theory that states the belief that muscles should functionally mold not only to the border but to the entire polished surface.

Category: Prosthodontics Notes

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