Pre-heating mitigates composite degradation
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Data
2015
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Resumo
D
ental composites cured at high temperatures show improved properties and higher
degrees of conversion; however, there is no information available about the effect of
pre-heating on material degradation. Objectives: This study evaluated the effect of pre-
heating on the degradation of composites, based on the analysis of radiopacity and silver
penetration using scanning electron microscopy/energy-dispersive X-ray spectroscopy
(SEM/EDS). Material and Methods: Thirty specimens were fabricated using a metallic
matri[ ( [ mm) and the composites Dura¿ll 9S (+eraeus .ul]er), =- ( M/ESPE), and
Z-350 (3M/ESPE), cured at 25°C (no pre-heating) or 60°C (pre-heating). Specimens were
stored sequentially in the following solutions: 1) water for 7 days (60°C), plus 0.1 N sodium
hydroxide (NaOH) for 14 days (60°C); 2) 50% silver nitrate (AgNO 3 ) for 10 days (60°C).
Specimens were radiographed at baseline and after each storage time, and the images
were evaluated in gray scale. After the storage protocol, samples were analyzed using
SEM/EDS to check the depth of silver penetration. Radiopacity and silver penetration data
were analyzed using ANOVA and Tukey’s tests (D=5%). Results: Radiopacity levels were
as follows: Dura¿ll VS Z-350 Z-250 (p 0.05). The depth of silver penetration into the
composites ranked as follows: Dura¿ll VS!Z-350!Z-250 (p 0.05). After storage in water/
NaOH, pre-heated specimens presented higher radiopacity values than non-pre-heated
specimens (p<0.05). There was a lower penetration of silver in pre-heated specimens
(p<0.05). Conclusions: Pre-heating at 60°C mitigated the degradation of composites based
on analysis of radiopacity and silver penetration depth.
Descrição
Palavras-chave
Composite resins, Scanning electron microscopy, Hot temperature, Silver nitrate, Radiography
Citação
SILVA, Jessika Calixto da et al. Pre-heating mitigates composite degradation. Journal of Applied Oral Science, Bauru, v. 23, n. 6, p. 571-579, 2015.