The correct answer is e. All of the above.
1. Is true. Definite pressure was advocated by many dentists, as it presumed that the occlusal loading during the impression would be the same as occlusal loading during function.
2. Is true. The mucostatic or nonpressure technique embodies the idea that the interfacial surface tension was the best way to retain dentures. Despite many advocates, it became known that the non-pressure technique could only be obtained by sacrificing the important concepts of maximum ridge coverage and border seal.
3. Is true. The selective pressure concept embodies the principles of both pressure and nonpressure procedures.
4. Is true. In selective pressure technique, the non-stress bearing areas are recorded with the least amount of pressure, and selective pressure is applied to certain areas of the maxillae and mandible that are capable of withstanding the forces of occlusion. These impression area made in trays that have been selectively relieved, therefore providing more space in some areas while at the same time having areas within the tray that have less space. The places that have less space or relief will transit more pressure during the impression. Ideally, this will then distribute a greater force during function to a more favorable part of the ridge/bone (such as the buccal shelf) and less pressure to unfavorable parts (such as sharp ridge crests or bony spicules). Clinical evidence favors the selective pressure technique.
5. Is true. Low-fusing Impression waxes are not sufficiently accurate for a final impression for complete dentures, but, are satisfactory as a corrective material for a small area and for border refining for a tray. Iowa wax or Type I ZnOE can both be used to correct minor defects.
References: Complete Denture Syllabus, NPDS, Bethesda
Rahn AL and Heartwell CM: Textbook of Complete Dentures, 5th Ed., Lea and Febiger, 1993.
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