Estudio experimental sobre manipulación y expansión de fraguado de los productos derivados del yeso usados en Odontología (I).

Resumo

Introduction Gypsum is a common mineral that has been used for centuries as a building material. In the medical field, was used for the first time in the treatment of bone bills, bandages reinforced. With slight modifications, the gypsum can be used for different applications in dentistry, such as emptying impressions, mount of articulating models or silica blinder in coatings for casting alloys. This is mainly due to the fact that you can easily change their properties. This work was to analyze the influence of manipulation in the physical properties around it, to evaluate its relevance in the result of the prosthetic work. Objectives 1) Ascertain the influence of mixing quality (mechanical vacuum or manual) does the values in setting expansion. 2) Know if the type of water used in the mix (current water of Canal Isabel II or double-distilled water) conditions those same parameters. 3) Check that the expansion data are within the limits set by international standard and provided to us by manufacturers. Material and method Samples of 500 g. trademark different for the five types of gypsum products which recognizes by specification number 25 ANSI/ADA (American National Standards Institute/ American Dental Association) (1989, ISO 6873, 1983). Has been used the test "T of Student" for the less than 30 data samples and the "Normality Test" for the rest of samples. Both were calculated the Confidence Limits or Interval for a reliability of 95%, as well as the P value or significance level. Results Mechanical vacuum significantly reduces, quasi as 50%, the setting expansion. The quality of water, meanwhile, has effect null on this property. 25.8% stones analyzed meets standard ISO 6873 in terms of setting expansion. Finally, 6.45% products are according the manufacturers as soon as setting expansion. Conclusions 1) The data support that the setting expansion is a physical phenomenon most affected by handling. 2) The data of setting expansion obtain in clinic circumstance not accord with provide to us by manufactures.