Microshear bond strength of a self etch adhesive to desensitized dentin

الملخص EN

Objectives:Hypersensitivity is a common clinical annoying multietiological problem.

Many desensitizing agents have been launched in market in different forms attempting to overcome such a problem.The purpose of this study was to evaluate the ability of a new desensitizing agent to occlude dentinal tubules and reduce their diameter as measured by envionemental scaning electron microscopy.At the same time its effect on microshear bond strength of a one step self etch adhesive would be investigated.

Materials and Methods: Fifteen buccal surfaces of sound human premolars were used.

Enamel was wet abraded to expose flat dentin surfaces, polished with diamond pastes and further demineralised with 37% phosphoric acid for 5 seconds.to remove the smear layer.

All specimens were first scanned using environmental scaning electron microscope .The number and diameters of dentinal tubules were measured.Specimens were randomly divided into three groups (n=5): G1,no brushing(control 1); G2,brushing with the new product gel containing a combination of ACP,KNO3 and NaFl ..G3,brushing with homecare Fluoride gel Brushed specimens were treated for 4 min per day, for 14 days.

Specimens were observed under ESEM for calculation of the mean number of occluded tubules and the mean diameters of the remaining ones.

Afterwards ,the desensitized specimens were treated with a contemporary one step self etch adhesive according to manufacturers instructions and composite microcylinders were packed.Microshear bond strength test was performed using a testing machine (Model LRX-plus; Lloyd Instruments Ltd., Fareham, UK) with a load cell of 5 kN and data were recorded using computer software (Nexygen-MT Lloyd Instruments).

Results:Statistical analysis of the data obtained revealed a significant dentinal tubule occlusion as well as a significant decrease in the apertures the remaining dentinal tubules for group 2 relative to groups 1 and 3, respectively.

Meanwhile,the mean valuesfor the microshear bond strengths were 22.961Mpa,23.596 Mpa and 22.778MPa for groups 1,2 and 3 respectively.These values were not statistically significantly different.

Conclusions: The new product,Relief ACP, proved its efficiency in obliterating the dentinal tubules and reducing their diameter more than the other two groups.At the same time micro shear bond strength of the single step self etch adhesive Xeno IV to desensitized dentin wasn’t reduced.