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Principles of edentulous ridge moulding with special regard to the ex-3-n-method
Miroslav Suvin
Sažetak
A total, especially a lower dental prosthesis still presents a difficult problem for the prosthesist. All contemporary methods have that much in common that they are based on the study of the tone and the direction of the muscle contraction surrounding the prosthetic base. Today prosthesists agree that the edge of the prosthetic base and its lateral surfaces must be adjusted to the muscle tone. Palpatory assessment of the muscle tone is not reliable and no scientific method for its measuring is yet known. Therefore, determination of the basal extension is left to the uncertain assessment bythe position of the individual impression tray. However, that position cannot be tested during mastication. The method of testing after Slack, and similar methods, are merely theory, because several muscle groups participate in each function and these muscle groups are difficult to differentiate. Nor can the position of the impression tray reliably tested during the swallowing process because there is a considerable physiological difference between experimental and habitual swallowing. The result of trimming the individual impression tray is usually a mucostatic tray by means of which it is not possible to obtain a true mucodynamic impression. Even with a too narrow (but not with a too short) impression tray it is still possible to take a mucodynamic impression if the partient is enabled, by the properties of the material used, to shape his future base himself. Such a material must have the following properties: constant plasticity at body temperature, the capacity of being easily §nd properly moulded far outside the margin of the impression tray, and a consistency fairly similar to the muscle tone. The impression tray in this case is only the bearer of the material and does not prejudice the extent of the base. Such a material is the HM-mass for situation impressions and the Ex-3-N-mass for functional impressions and for rebasing (after Meist).
Apart from the properties described, these materials are particularly suitable because they have no chemically determined period of setting and therefore sufficient time remains to mould it at mouth temperature in harmony with the muscle tone. It ought to be emphasized that the therapeutist can control the moulding and determine the exact moment when it is terminated. One of the preconditions for successful moulding is a good knowledge of the application of the material, while the method of active functional moulding is nothing new. Our positive one - year experience showed us that even in the most serious cases the form of the mandibular ridge is not essential for the stability of the prosthesis, when this material is applied. This finding propted us to report and reccomend this new method.
Ključne riječi
Hrčak ID:
108734
URI
Datum izdavanja:
15.9.1969.
Posjeta: 2.014 *