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From Volume 49, Issue 10, November 2022 | Pages 852-855


Andre D Xavier


Restorative Dentistry, Leeds Dental Institute

Articles by Andre D Xavier

Email Andre D Xavier

Hannah Beddis

Specialty Registrar in Restorative Dentistry, Leeds Dental Institute, Leeds, UK

Articles by Hannah Beddis


The success of an upper complete denture is dependent on various factors, including retention and stability during function, comfort and aesthetics. Physical retention of the denture depends upon adequate extension and fit, along with a good border seal. The border seal of an upper denture relies upon extension of the flanges to the functional depth and width of the sulci, and the post-dam. The post-dam of an upper complete denture is a raised ‘lip’ along the posterior border that becomes embedded into the palatal mucosa. This ‘embedding’ of the border within the mucosa helps to create the seal. This technique tip highlights the location and shape of the post-dam, as well as the clinical stages involved in its construction.

CPD/Clinical Relevance: Successful location and application of a post dam will help in retention of an upper complete denture.


Retention of a denture is defined as resistance to vertical movement away from the underlying mucosa.1 Retention can be affected by the three surfaces of a denture: occlusal, polished and impression (or fitting) surface. Retentive forces can be exerted by the oral musculature, or by the physical forces associated with the continuous thin film of saliva between the denture and the mucosa.2 These physical forces largely depend upon the accuracy and form of the impression, and the polished surfaces, to provide a border seal. The physical forces contributing to retention rely on the following attributes.1

Maximum extension over the denture-bearing area is required for optimum retention: the physical retention of a denture is proportional to the area of the impression surface. Therefore, it is important that during the impression stage the functional width and depth of the sulcus is obtained using careful and effective border moulding.

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