[Evaluation of cervical discrepancy of gold crowns in stone dies from various impression materials].
A stainless steel master die simulating a dental preparation for crown was used to make 3 gold castings from wax patterns obtained in 3 different ways: a) directly from the naked master die; b) from the same master die with a copper coping 30 microns thick; and c) with a similar copper coping, but 40 microns thick. The discrepancies of fit of the 3 master gold crowns were evaluated in 99 stones dies (33 for each casting) obtained from 11 different elastomeric impression materials (3 replicae of each). The results showed that: 1) stone dies with no coping presented a medium discrepancy of 284 microns, inadequate for clinical use; 2) the 30 microns and 40 microns copings presented medium discrepancies of 18 and 9 microns respectively, both suitable for clinical use. Thus, the use of copings tend to equalize the cervical discrepancy of fit of gold crowns, whatever be the elastomeric impression material used.
Mantovani
A V
AV
Departamento de Materiais Denários e Prótese, Universidade de São Paulo.
Stephano
C B
CB
Roselino
R F
RF
Roselino
R B
RB
Campos
G M
GM
D003442:Crowns; D003760:Dental Impression Materials; D003761:Dental Impression Technique; D003763:Dental Leakage / Q000517:prevention & control*; D006047:Gold Alloys; D003765:Models, Dental; D012826:Silicone Elastomers
D003760:Dental Impression Materials; D006047:Gold Alloys; D012826:Silicone Elastomers
Avaliação do desajuste cervical de coroas de liga de ouro em troquéis de gesso-pedra, obtidos a partir de materiais de moldagens diversos.