IADR Abstract Archives
Assessment of Bonding Interface After Microtensile Test Using Non-invasive Tomography
Objectives: To investigate the influence of crosshead speed of microtensile bond strength (MTBS) test and flowable composite lining on the bonding interface using swept-source optical coherence tomography (SS-OCT).
Methods: Self-etch adhesive (Clearfil SE Bond, Kuraray) and universal composite (Clearfil AP-X, Kuraray) were applied on flat dentin surfaces prepared from human premolars with or without flowable composite lining (Estelite Flow Quick, Tokuyama). After storage (37°C, 24h), the specimens were cut into beam of 0.81mm2 and the MTBS test was performed with crosshead speed of 1mm/min and 10mm/min (n=10/group). 2D images of specimens before and after the test were recorded using SS-OCT (Santec, Japan) to observe the change of interface. The images of SS-OCT were digitally analyzed to measure the crack length and crack area in percentage using ImageJ (version 1.47v). Representative specimens were prepared to confirm the findings under confocal laser scanning microscope. Results were statistically compared between the groups (Two-way ANOVA, t-test, p<0.05).
Results: There was no significant difference in MTBS between the groups using two mentioned crosshead speeds, while MTBS of the groups using universal composite was statistically lower compared to ones using flowable composite lining(p<0.05). On OCT viewing, the group using lining of flowable resin with the speed of 10 mm/min showed significantly more cracks in terms of both length and area of crack than one using same method of lining with the speed of 1mm/min(p<0.05); while there was no difference of crack percentage in the groups using only universal composite.
Conclusions: Crosshead speed did not affect MTBS value but caused internal damage on substrate. Flowable composite tends to be more sensitive on the different crosshead speeds in the view point of dentin cracks occurrence. OCT can visualize cracks on interface after debonding of restoration.
Methods: Self-etch adhesive (Clearfil SE Bond, Kuraray) and universal composite (Clearfil AP-X, Kuraray) were applied on flat dentin surfaces prepared from human premolars with or without flowable composite lining (Estelite Flow Quick, Tokuyama). After storage (37°C, 24h), the specimens were cut into beam of 0.81mm2 and the MTBS test was performed with crosshead speed of 1mm/min and 10mm/min (n=10/group). 2D images of specimens before and after the test were recorded using SS-OCT (Santec, Japan) to observe the change of interface. The images of SS-OCT were digitally analyzed to measure the crack length and crack area in percentage using ImageJ (version 1.47v). Representative specimens were prepared to confirm the findings under confocal laser scanning microscope. Results were statistically compared between the groups (Two-way ANOVA, t-test, p<0.05).
Results: There was no significant difference in MTBS between the groups using two mentioned crosshead speeds, while MTBS of the groups using universal composite was statistically lower compared to ones using flowable composite lining(p<0.05). On OCT viewing, the group using lining of flowable resin with the speed of 10 mm/min showed significantly more cracks in terms of both length and area of crack than one using same method of lining with the speed of 1mm/min(p<0.05); while there was no difference of crack percentage in the groups using only universal composite.
Conclusions: Crosshead speed did not affect MTBS value but caused internal damage on substrate. Flowable composite tends to be more sensitive on the different crosshead speeds in the view point of dentin cracks occurrence. OCT can visualize cracks on interface after debonding of restoration.
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