| ORIGINAL ARTICLE |
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| Year : 2021 | Volume
: 24
| Issue : 4 | Page : 393-398 |
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Shear bond strength of the adhesive/dentin interface after different etching protocols
Rodrigo Galo1, Mayara Terra Marinho2, Paloma Dias da Silva Telles3, Maria Cristina Borsatto4
1 Department of Prosthodontics and Dental Materials, School of Dentistry of Ribeirão Preto, University of São Paulo, São Paulo, Brazil
2 Department of Pediatric Clinics, Dental School of Ribeirão Preto, University of São Paulo, São Paulo, Brazil
3 Department of Social and Pediatric Dentistry, Federal University of Bahia, Salvador, Brazil
4 Department of Pediatric Clinics, Dental School of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil
Correspondence Address:
Dr. Rodrigo Galo
Department of Prosthodontics and Dental Materials, Dental School of Ribeirão Preto, University of São Paulo, Avenida do Café, S/N, Monte Alegre. CEP: 14040-904, Ribeirão Preto, São Paulo
Brazil
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/jcd.jcd_223_21
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Background : Lack of bond stability between the composite resin and dentin remains one of the main reasons for having to replace esthetic restorations.
Aim : This study aimed to evaluate the influence of chlorhexidine (CHX) on the bond strength of a total etching system to dentin tissue after degradation of the adhesive interface.
Materials and Methods : One hundred and eighty fragments of human molars were divided into three groups (n = 15) according to the materials used during the acid-etching step: Group 1 (control), 37% phosphoric acid; Group 2, a combined solution of 37% phosphoric acid and 2% CHX; and Group 3, 37% phosphoric acid followed by 2% CHX. Following the restorative procedures, the groups were divided into four subgroups according to the number of thermal cycles (TC) and to the time of storage in water (SW), and then subjected to a shear strength test, until fracture: (A) 0 TC/24-h SW; (B) 500 TC/1-week SW; (C) 2,000 TC/1-month SW; and (D) 12,000 TC/6-month SW. Two-way analysis of variance and Duncan's complementary test were used to perform multiple comparisons.
Results : After the 24-h and 1-week SW time periods, no statistically significant difference was found among the shear strength values of the control and the experimental groups: 5.48 ± 0.59 MPa, 5.44 ± 0.56 MPa, and 5.65 ± 0.94 MPa for G1, G2, and G3, respectively. However, the shear strength values decreased significantly in all the study groups after 1 month, namely 3.60 ± 0.41 MPa, 3.08 ± 0.65 MPa, and 3.49 ± 0.23 MPa for G1, G2, and G3, respectively. After 6 months, similar results were found for G1 and G3, namely 2.77 ± 0.58 MPa and 1.74 ± 0.52 MPa, respectively, whereas the 0.77 ± 0.26 MPa value found for G2 was significantly lower than those found for the G1 and G3 groups. No differences were found between the groups with respect to fracture-type frequencies.
Conclusion : The use of CHX as an agent to rehydrate the dentin had a negative influence on bond strength.
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