| Cervical wedge-shaped defects are common in clinic. The hyper-mineralized surface layer was presence and the lesion dentin was also called cervical sclerotic dentin(CSD). Sclerotic dentin is the presence of sclerotic cast within dentinal tubules and hyper-mineralized surface that precluded optimal resin infiltration into the dentinal tubules.So the filling resin often fall off and the micro leakage often occurs on the dentin bonding interface. Sometimes even the secondary caries can be found on the bonding interface. Our objective in this paper is to observe the shear bond strength and the dentin bonding interface of cervical sclerotic dentin and normal dentin(ND) by different treatments. In order to provide useful help on resin adhesive for clinical sclerotic dentin. Objective: To compare the shear strength, ultrastructural of the dentin interface and interfacial nanoleakage of bonding on CSD and ND used 4 different treatments. Study 1: To compare the shear bond strength on CSD and ND by different treatments. Methods: A total of 40 non-caries premolars due to periodontal disease with typical wedge-shaped defect were randomly divided into 4 groups(C1, C2, C3, C4) as the experimental group, with 10 teeth in each group. Another 40 non-caries premolars were chosen due to orthodontic. Ground their crown enamel to expose the dentin surface absolutely. And then randomly divided them into 4 groups(N1, N2, N3, N4) as the control group, with 10 teeth in each group. Respectively by different treatment methods: C1, N1 were bonded with Easy One(self-etching adhesive). C2, N2 were processed with 15% EDTA and then bonded with Easy One. C3, N3 were processed with 35% phosphoric acid and then bonded with Easy One. C4, N4 were processed with 35% phosphoric acid treatment and then bonded with Single Bond 2(total-etch adhesive). Then placed the composite resin restorations into all cavities in an incremental manner. After that, each group was thermocycled at 5000 cycles. The mTBS values of specimens were tested. The fracture mode of each group was observed by scanningelectron microscope(SEM). Result: 1、:Two-way ANVOA revealed significant influence of both the type of dentin and the sorts of treatments tested on shear bond strength(P<0.05). 2、The shear bond strength of group C1 was the lowest of group CSD, while there were no statistically significant differences among C2、C3、C4 who had the similar bond strength(P>0.05). 3、There were no statistically significant differences among 4 groups in group ND(P>0.05). 4、There were no statistically significant differences of neither the type of dentin nor the sorts of treatments tested on the fracture mode(P>0.05). Conclusion: 1、The shear bond strength on CSD was weaker than ND. 2、Pretreatment of sclerotic dentin surface by EDTA can improve the bond strength when using Easy One, and it has similar effect as phosphate. 3、There were no statistically significant differences of neither the type of dentin nor the sorts of treatments tested on the fracture mode. Study 2: Using CLSM to compare the dentin bonding interface on CSD and ND by different treatments. Methods: A total of 40 non-caries premolars due to periodontal disease with typical wedge-shaped defect were randomly divided into 4 groups(C5, C6, C7, C8) as the experimental group, with 10 teeth in each group. Another 40 non-caries premolars were chosen due to orthodontic. Artificially wedge-shaped lesions were made in sound premolars and then randomly divided them into 4 groups(N5, N6, N7, N8) as the control group, with 10 teeth in each group. Respectively by different treatment methods(the same as study 1). Then placed the composite resin restorations into all cavities in an incremental manner. The primer component was labeled with Rhodamine B. CLSM observed the hybrid layer and the resin tag of the bonding interface. Result: 1、:Two-way ANVOA revealed significant influence of both the type of dentin and the sorts of treatments tested on the hybrid layer and the resin tag of the bonding interface.(P<0.05). 2、The hybrid layer and the resin tag of group C6 were thicker and longer than group C5, while there were no statistically significant differences between C6 and C7(P>0.05). The hybrid layer was thickest and the resintag was longest of group C8 in group CSD(P<0.05). 3、The hybrid layer of group N8 was thickest in group ND(P<0.05), while there were no statistically significant differences among 4 groups in group ND(P>0.05). 4、The hybrid layer and the resin tag were thicker and longer in ND than in CSD(P<0.05). 5、The hybrid layer and the resin tag were thicker and longer using Single Bond 2 than using Easy One(P<0.05). Conclusion: 1、The hybrid layer and the resin tag were thicker and longer in ND than in CSD when using the same treatment. 2、Pretreatment of sclerotic dentin surface by EDTA can improve the quality of hybrid layer and the resin tag when using Easy One, and it has similar effect as phosphate. Study 3: Using CLSM to compare the nanoleakage on CSD and ND by different treatments. Methods: A total of 40 non-caries premolars due to periodontal disease with typical wedge-shaped defect were randomly divided into 4 groups(C9, C10, C11, C12) as the experimental group, with 10 teeth in each group. Another 40 non-caries premolars were chosen due to orthodontic. Artificially wedge-shaped lesions were made in sound premolars and then randomly divided them into 4 groups(N9, N10, N11, N12) as the control group, with 10 teeth in each group. Respectively by different treatment methods(the same as study 1). Then placed the composite resin restorations into all cavities in an incremental manner. Each group was individually exposed to 0.1% rhodamine B in 50% alcohol solutions for 24 hrs. After that, each group was thermocycled at 5000 cycles. CLSM observed the nanoleakage of all groups. Result: 1、:Two-way ANVOA revealed significant influence of both the type of dentin and the sorts of treatments tested on the nanoleakage of the bonding interface.(P<0.05). 2、The nanoleakage of group C10 were shortest in group CSD(P<0.05), and the nanoleakage of group C12 were longest in group CSD, while there were no statistically significant differences between C9 and C11(P > 0.05). 3 、 The nanoleakage was longest of group N12 in group ND, while there were no statistically significant differences among N9, N10, N11(P > 0.05). 4 、 The nanoleakage was longer in ND than in CSD(P<0.05). 5、The nanoleakage waslonger using Single Bond 2 than using Easy One(P<0.05). Conclusion: 1、The nanoleakage was shorter in CSD than in ND when using the same treatment. 2、The nanoleakage was shorter when using Easy One than using Single Bond 2. 3、Pretreatment of sclerotic dentin surface by EDTA can improve the quality of hybrid layer and the resin tag when using Easy One, and it has similar effect as phosphate. |
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