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Zinc oxide eugenol paste jeopardises the adhesive bonding to primary dentine
C W Pires1, T L Lenzi2, F Z M Soares3
1University Center of Serra Gaúcha, Caxias do Sul, RS, Brazil. cwpodonto@gmail.com.
Aim:
This was to evaluate the influence of root canal filling pastes on microshear bond strength (µSBS) of an adhesive system to primary dentine.
Methods:
Human (32) primary molars were randomly assigned into four experimental groups (n = 8): zinc oxide eugenol paste (ZOE); iodoform paste (Guedes-Pinto paste); calcium hydroxide paste thickened with zinc oxide; and no filling paste (control). Flat dentine surfaces were covered with a 1 mm-thick layer of the pastes for 15 min at 37 °C. The pastes were mechanically removed from dentine surfaces, followed by rinsing and drying. After adhesive application (Adper Single Bond 2, 3M ESPE), starch tubes were placed over pre-treated dentine and filled with composite resin (Z250, 3M ESPE). The µSBS test was performed after 24 h of water storage at 37 °C. The failure mode was evaluated using a stereomicroscope. The µSBS values (MPa) were analysed with one-way ANOVA and Tukey post-hoc tests (α = 0.05).
Results:
The lowest µSBS values were achieved when ZOE was used. No difference was found among other filling pastes compared with control group. All specimens showed adhesive/mixed failures.
Conclusions:
Zinc oxide eugenol paste negatively influenced the bond strength of adhesive systems to primary dentine. Iodoform-based Guedes-Pinto paste and calcium hydroxide paste thickened with zinc oxide did not influence the microshear bond strength values.
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