Title: Multidimensional functional impression in the edentulous elderly
Abstract:
Multidimensional functional impression is the solution for completely edentulous patients, leaving aside conventional techniques that produce dentures but not oral rehabilitations.
The basis that makes possible this concept are:
1- A thorough diagnosis, based on a general and oral examination that allows selecting the best technique and materials.
2- Good clinical conditions, which determine the procedures to take primary and secondary impressions successfully, to obtain support, retention and stability. This is the first stage of a physiological and functional impression.
Reproducing supporting tissues is not enough, it is important to know the limits of the impressions. This means that the borders of the individual tray will be absolutely defined. Muscles insertion, mobility and contraction must be taken into account, respecting normal tongue, cheeks and lips activities. This is the second step of the functional impression.
3- Piezographic procedure. To obtain an integral physiological and completely functional impression it is necessary to determine the shape and volume of the new prosthodontic appliances. Piezography will provide a personalized volume and shape of the whole polished surface and will also determine the future buccal and lingual aspects of the artificial teeth (position and width).
The volume depends on the ridges conditions. Generous ridges may deserve a piezography with more volume. They are able to receive heavy loads during mastication. Consequently, masticatory efficiency will increase and better conditions may be provided to select different foods consistencies. To obtain wider piezographic records, it is necessary to use regular flow impression materials.
On the contrary, when ridges conditions are thin it will be necessary to select narrow occlusal surfaces. In these circumstances, thinner piezographic registers will be necessary and lighter flow impression materials must be used.
Piezography’s new philosophical focus takes into account two stability concepts: the mechanical one, respecting the functional activity of the surrounding muscles and the biological stability, avoiding ridges overload.
The volume obtained as result of the piezographic record represents the prosthodontic space, formerly neutral zone. The prosthetic appliance must be constructed inside it, occupying the prosthodontic space in its shape and volume. Balanced muscles will allow comfort for the patient during different oral functions. That is why the patient says: "I feel as if I have nothing inside my mouth".
With piezography the patients create their own records following our guidance, that is why it is an interactive technique.
When taking the piezographic register a non-shaped impression material is poured inside the mouth. While patients repeat the phonemes (sounds): “Sees, so, se, the, te, moo” they create the impression’s shape, width and location.
Shape and volume depend on the tongue, cheeks and lips’ muscles mobility and strength (ugokikata-chikara). Depending in some way on the quality of the voice. If the phonemes (sounds) are repeated with a very low voice, the shape and volume of the piezographic record will not be accurate. Consequently, a loud voice is needed. With a loud voice more mobility and strength will be obtained. So instead of the sound “so” (with a soft voice) the patient repeats “SO” (with a strong voice), and the same with the sound “SIS” instead of “sis” and “SE” instead of “se”.
4- Washing technique. The last stage of Multidimensional Functional Impression is the washing technique, performed after the final trial of the artificial teeth and after evaluating occlusion, phonetics and aesthetics. With a high flow impression material the polished surfaces are covered and all the phonemes (sounds) are repeated for the last time. The Multidimensional Functional Impression for the completely edentulous is finished, being a clinically obtained impression.
