[Effects of carboidiimide with different bonding techniques on the property of dentin bonding].

PURPOSE: To explore the effects of carbodiimide combined with different bonding techniques on the property of dentin bonding. METHODS: 64 third molars in vitro were randomly divided into 8 groups(n=8), including EWB and EWBa (no pretreatment+ethanol-wet bonding), E-EWB and E-EWBa (0.5 mol/L EDC+ethanol-wet bonding), E-WB and E-WBa (0.5 mol/L EDC+water-wet bonding), E-DB and E-Dba (0.5 mol/L EDC+dry bonding). Group EWB, E-EWB, E-WB and E-DB were immediate groups, while group EWBa, E-EWBa, E-WBa and E-DBa were aging groups. Six specimens in each group were randomly chosen to test shear bonding strength and then observe failure patterns. The remaining specimens were used to observe bonding interface under SEM. SPSS 20.0 software package was used for statistical analysis of the data. RESULTS: There was no significant difference in shear bonding strength between group EWB and E-EWB, group E-EWB and E-WB(P＞0.05), while shear bounding strength in group E-EWB and E-WB were significantly greater than group E-DB(P＜0.05). The shear bonding strength of group E-EWBa was significantly greater than group EWBa (P＜0.05). The shear bonding strength of group E-EWBa, E-WBa and E-DBa was gradually decreased, and their differences were significant (P＜0.05). The factors of EDC, bonding techniques and aging played a significant role in shear bonding strength (P＜0.05). Interactions between EDC and aging was significant (P＜0.05), and that between bonding techniques and aging was also significant (P＜0.05). The main failure modes of the water-wet bonding and the ethanol-wet bonding were resin failure, adhesive interface failure and mixed failure. The main failure of dry bonding was adhesive interface failure. The thickest and densest hybrid layer were found in group E-EWB. Some tiny cracks were presented between the hybrid layer and adhesives layer in group EWBa and E-EWBa. Partially uneven cracks existed in the hybrid layer in group E-WBa, and that was more obvious in group E-DBa. CONCLUSIONS: EDC pretreatment combined with ethanol-wet adhesive technique acquires the optimal shear bonding strength and the durability of dentin bonding.