Impression Procedures for Stability of Complete Dentures

Abstract

Patient and dentist both contribute essential components to the stability of complete dentures. Thorough knowledge of the structure and function of the oral tissues, which are the major support of denture bases, enables the dentist to select impression materials and techniques which provide dentures that are physiologically favorable to oral health and exhibit maximum stability. The masticatory mucosa, and not the bone, is the chief anatomic support of the denture base; the lining mucosa, because it is so freely movable, is less suitable for stability, but contributes much to retention through peripheral seal. Despite its apparent toughness, the masticatory mucosa is quickly deprived of blood supply by deformation; brief, intermittent deformation is well tolerated and may be physiologically favorable. Mild persistent deformation does not injure the lining mucosa, but it will induce pathologic changes in the masticatory mucosa. Thiokol rubber is preferred for final impressions because it registers fine detail, adapts itself perfectly to soft tissue contours without causing deformation, and permits a most critical attitude in evaluating finished impressions. A well fitted individual tray, properly extended and with space provided for adequate thickness of rubber, is essential. Dentures constructed in conformity with the biologic needs of the oral mucosa have been found to fulfill all reasonable demands for stability and retention without risk of pathologic changes.