Evaluation of the conversion degree, microhardness, and surface roughness of composite resins used after their expiration date.
This study evaluated the conversion degree associated with microhardness and surface roughness of four composite resins used 180 days before and after their expiration dates. Ten specimens of each composite were made in a Teflon matrix (2 mm x 7 mm), separated into two groups (n = 10), and submitted to Vickers microhardness (a 10 N load for 15 seconds), R(a)roughness (cut-off 0.25 mm), and conversion degree evaluation. The data submitted to the two-way ANOVA (p < 0.05) showed a reduction in microhardness for the composites used after their expiration dates. It was concluded that the expired composites had altered properties.
Piracicaba School of Dentistry, State University of Campinas, Piracicaba, Sao Paolo, Brazil.
Lucas da Fonseca Roberti
Lda F
Garcia
Lourenco de Moraes Rego
Lde M
Roselino
Fernanda de Carvalho Panzeri
Fde C
Pires-de-Souza
Simonides
S
Consani
D002244:Carbon / Q000737:chemistry; D055598:Chemical Phenomena; D003188:Composite Resins / Q000737:chemistry*; D003764:Dental Materials / Q000737:chemistry*; D004356:Drug Storage; D006244:Hardness; D006801:Humans; D008422:Materials Testing; D058105:Polymerization; D012822:Silicon Dioxide / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties; D013997:Time Factors; D015040:Zirconium / Q000737:chemistry
C084111:Charisma composite resin; D003188:Composite Resins; D003764:Dental Materials; C467914:TPH spectrum; C083568:Z100 composite resin; D002244:Carbon; D012822:Silicon Dioxide; C039734:Durafill; D015040:Zirconium