Microhardness of resin cements in the intraradicular environment: effects of water storage and softening treament.
Dent Mater
; 25(7): 868-76, 2009 Jul.
Article
en En
| MEDLINE
| ID: mdl-19217152
ABSTRACT
OBJECTIVES:
To analyze the microhardness of four dual-cure resin cements used for cementing fiber-reinforced posts under the following conditions after 7 days of storage in water, after additional 24h of immersion in 75% ethanol, and after 3 months of storage in water. Hardness measurements were taken at the cervical, middle and apical thirds along the cement line.METHODS:
Root canals of 40 bovine incisors were prepared for post space. Fibrekor glass fiber-reinforced posts (Jeneric/Pentron) of 1mm in diameter were cemented using Panavia F 2.0 (Kuraray), Variolink (Ivoclar-Vivadent), Rely X Unicem (3M ESPE) or Duolink (Bisco) (N=10). After 7 days of water storage at 37 degrees C, half the sample (N=5) was longitudinally sectioned and the initial microhardness measured along the cement line from cervical to apex. These same samples were further immersed in 75% ethanol for 24h and reassessed. The remaining half (N=5) was kept unsectioned in deionized water at 37 degrees C for 3 months, followed by sectioning and measuring. Data were analyzed by a series of two-way ANOVA and Tukey tests at alpha=5%.RESULTS:
Statistically significant differences were identified among the cements, thirds and conditions. Significant interactions were also observed between cements and thirds and between cements and conditions. Panavia F exhibited significantly higher initial microhardness than the other three cements, which showed no statistical difference among themselves. Variolink and Duolink showed significantly higher microhardness values in the cervical third, without significant difference among the thirds for the other cements. Immersion in ethanol significantly reduced the hardness values for all cements, regardless of the thirds. Storage in water for 3 months had no influence on the hardness of most of the cements, with the exception of Unicem that showed a significant increase in the hardness values after this period.SIGNIFICANCE:
Results showed heterogeneity in the microhardness of the cements inside the canal. All cements presented some degree of softening after ethanol treatment, which suggests instability of the polymer. The quality of curing of resin cements in the root canal environment seems unpredictable and highly material dependent.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Solventes
/
Agua
/
Cementos de Resina
/
Cavidad Pulpar
Tipo de estudio:
Prognostic_studies
Límite:
Animals
Idioma:
En
Revista:
Dent Mater
Asunto de la revista:
ODONTOLOGIA
Año:
2009
Tipo del documento:
Article
País de afiliación:
Brasil