Study of three types of desensitizers in dentin bonding strength

One hundred and twenty human molars without decay (premolars and complete third molars) freshly extracted for orthodontic purposes were used in the study to explore the impact of application of three kinds of desensitizers on self-etching/all-etching bond strength of dentin. The roots were ground along the cementoenamel junction (CEJ), the residual crowns were divided into two parts along mesial and distal direction, and the enamel layer was removed. The dentin was ground into standard pieces of 3x3x3 mm and then polished using alumina waterproof abrasive paper. Two hundred and forty specimens were divided into two groups according to self-etching bond (OptiBond, iBond, XenoIV) and all-etching bond (OptiBond, iBond, Probond). Each of the two groups were subdivided into three groups with different brands, and then further subdivided into three experimental groups and a control group (10 samples in each final group). The surface of dentin coated with desensitizer was examined using scanning electron microscope. Results showed that only the shear strength of iBond + Ddes + Z100 resin group was lower compared to the control group (P < 0.05). The comparison of the resin shear strength in other experimental groups with the control groups demonstrated no statistically significant difference (P > 0.05). The shear strength of Optibond + Gluma, Optibond + Ddes, iBond + Ddes + Z100 resin group in all-etching bond group and the experimental groups in Probond group was lower than in the control group (P < 0.05). The resin shear strength in other groups did not differ from the controls (P > 0.05).