Impressions for Complete Denture

An impression is defined as a negative picture of the edentulous areas where the teeth have been removed , made by materials that become relatively hard or set while in contact with these tissues

Objectives of complete denture impression are: 1- Preservation of the alveolar ridge. 2- Support. 3- Stability. 4- Retention. 5- Esthetic.

Objectives of complete denture impression Preservation of the alveolar ridge: This can be achieved by making impression to minimize the soft tissue abuse and bone resorption by: A- Covering as much of the supporting areas as possible. B- Using pressure within the physiologic limits of the tissue.

Objectives of complete denture impression Denture support: is the resistance to vertical forces of mastication and to occlusal or other forces applied in a direction toward the basal seat. It is provided by the maxillary and mandibular bones and their covering of mucosal tissues.

Objectives of complete denture impression The areas of denture support are divided into primary, secondary stress bearing areas: Primary supporting areas: a- Maxillary - Posterior ridges, Flat areas of the palate. b- Mandibular - Buccal, Posterior ridges, Retro molar pad area. - Secondary supporting areas: a- Maxillary - Anterior ridge (Rugae area),maxillary tuberosity, All ridge slop. b- Mandibular - Anterior ridge, All ridge slops.

Objectives of complete denture impression Denture stability: is the resistance of a denture to movement on its tissue foundation, especially to lateral (horizontal) forces as opposed to vertical displacement, these horizontal forces are caused during function of chewing, talking, etc

Objectives of complete denture impression Denture Retention : is the resistance in the movement of a denture away from its tissue foundation especially in a vertical direction, resistance to removal in a direction opposite to that of its insertion.

Objectives of complete denture impression Esthetic :in impression making refers to the development of labial and buccal borders so that they are not only retentive but also support the lips and cheeks properly. Border thickness should varied with needs of each patient in accordance with the extent of residual ridge loss.

Oral mucosal behavior during function

Impression Taking Procedures (theories of making impression) - The mucostatic impression technique - The mucocompressive (dynamic) impression technique - The selective pressure technique

The impression in the maxillary region: Primary maxillary impression

Secondary maxillary impression:

The impression in the mandibular region Primary mandibular impression

Secondary mandibular impression