Does the contact time of alginate with plaster cast influence its properties?
Braz. oral res
;
26(3): 197-201, May-June 2012. ilus, tab
Article
Dans Anglais
| LILACS
| ID: lil-622930
ABSTRACT
The aim of this study was to verify the influence of the time of contact between alginate and gypsum after the modeling procedure on the properties of the plaster cast, such as surface detail, dimensional stability and microhardness. Thirty cylindrical specimens of orthodontic gypsum Type III were made by means of impressions of a stainless steel master model which had five reference lines in the upper surface. The samples were divided into two groups Group 1 (G1) - with time of contact of 1 hour; and Group 2 (G2) - 12 hours of contact. All the specimens were stored up to 48 hours until they underwent laboratory testing. Surface detail and dimensional stability were tested by one calibrated examiner using a visual analysis and a profilometer (Profile Projector Nikon model 6C, Nikon Corporation, Tokyo, Japan), respectively, to evaluate the quality of reproduction of the lines and the distances between them. The microhardness was determined for each sample by making six indentations with a Vickers diamond pyramid indenter (Buehler, Lake Bluff, USA) under a load of 100 gF for 15 s. The results showed significant difference (P £ 0.05) between groups in two of the three properties examined surface detail and microhardness, which decreased as the time of contact rose. The 12-hour time of contact between alginate and the plaster cast is not recommended because it influences the quality of the plaster cast.
Texte intégral:
Disponible
Indice:
LILAS (Amériques)
Sujet Principal:
Sulfate de calcium
/
Plâtres chirurgicaux
/
Technique de prise d'empreinte
/
Matériaux empreinte dentaire
/
Alginates
Type d'étude:
Études d'évaluation
/
Étude pronostique
langue:
Anglais
Texte intégral:
Braz. oral res
Thème du journal:
Dentisterie
Année:
2012
Type:
Article
Pays d'affiliation:
Brésil
Institution/Pays d'affiliation:
Universidade Federal do Rio de Janeiro/BR
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