Effect of an 8.0% arginine and calcium carbonate in-office desensitizing paste on the microtensile bond strength of self-etching dental adhesives to human dentin

Purpose: To evaluate in the laboratory the effect of an 8.0% arginine and calcium carbonate desensitizing paste in occluding open dentin tubules and examine the effect of bonding between the adhesive agents and dentin after being treated with the desensitizing paste. Methods: Two self-etching adhesives were used. Intact human premolars extracted for orthodontic reasons were used within 3 months of extraction. The occlusal enamel was removed and dentin slices were polished. The dentin tubules were opened by etching with a 1% citric acid solution for 20 seconds to simulate a postoperative sensitivity model. Then the specimens were randomly assigned into five groups. Group A: specimens without any treatment (control). Group B: specimens were polished with a slurry (SiO₂) for 30 seconds. Groups C, D and E: 8.0% arginine and calcium carbonate desensitizing paste was applied. Specimens in Group C were polished for 3 seconds, and then repeated for another 3 seconds for a total of 6 seconds, according to the manufacturer's instructions: specimens in Group D were polished twice for 9 seconds for a total of 18 seconds; and specimens in Group E were treated for an extended time of 30 seconds. Each group was randomly divided into two sub-groups in order to evaluate the effect on two diffedhesive agents. A one-step self-etching adhesive agent (G-Bond) and a two-step self-etching adhesive agent (Fl-Bond II) were applied following the manufacturers' instructions. Then microtensile bond strengths of the 10 groups were tested. SEM was used to evaluate the laboratory effect of the desensitizing paste in occluding open dentin tubules. Statistical analysis was carried out using SPSS version 16.0. Results: The SEM observations showed that the 8.0% arginine and calcium carbonate desensitizing paste could occlude the dentin tubules effectively, and thus may have potential benefits in preventing postoperative sensitivity based on the hydrodynamic theory. An extended application time of 18 or 30 seconds showed no adverse effect of the desensitizing paste on the bonding performance to dentin when using self-etching adhesives containing functional monomers such as 4-MET like G-Bond.