Remineralization Potential and Shear Bond Strength of Surface Treated Hypomineralized Enamel in Bonding of Orthodontic Brackets: An In Vitro Study

Aim: To investigate the effect of different conditioning methods on remineralization potential of hypomineralized enamel and its shear bond strength (SBS) to orthodontic brackets. Materials and Methods: An in vitro study was conducted at Mansoura University, Egypt. Eighty premolars were collected and randomly classified into four groups ( n = 20 each) as follows: Group 1. Control (sound teeth), Group 2. Demineralized, Group 3. Demineralized and treated with nanohydroxyapatite (nano-HA) varnish, Group 4. Demineralized and treated with casein phosphopeptide–amorphous calcium phosphate (CPP–ACP) paste. To detect the rate of remineralization on the surface of treated specimens, energy dispersive X-ray (EDX) analysis was used in conjunction with the scanning electron microscope (SEM). The SBS was measured with a universal testing machine. One-way ANOVA test was carried out to analyze differences between the tested groups. Result: SE micrographs of Group 3 and Group 4 specimens showed smoother and less porous enamel surface than that of the Group 2 specimens. EDX analysis showed highest calcium (Ca) (25.47%) and phosphorous (P) (12.76%) values for Group 4 while Group 2 showed the lowest Ca and P values (16.96%) and (10.20%), respectively ( P < .001). Demineralized enamel showed lowest (3.70 MPa) SBS mean value compared to sound (10.69 MPa) and remineralized enamel (Group 3—9.90 MPa, Group 4—10.32 MPa) ( P < .001). Conclusion: Nano-HA and CPP–ACP have equal remineralizing effect on hypomineralized enamel lesions and positive influence on SBS.

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A Comparative Evaluation of Three Commercially Available Dentin Desensitizers on the Shear Bond Strength of Composite Resins: An in vitro Study

Journal of Contemporary Dentistry ◽

10.5005/jp-journals-10031-1109 ◽

2015 ◽

Vol 5 (2) ◽

pp. 65-68

Author(s):

Shruti Patil ◽

Prajna Shetty

Keyword(s):

Bond Strength ◽

Comparative Evaluation ◽

Shear Bond Strength ◽

In Vitro Study ◽

Composite Resins ◽

Group 4 ◽

Group 3 ◽

Group 2 ◽

Group 1

ABSTRACT Background The dentin desensitizers available for in-office application for prevention and/or treatment of post restorative dentinal hypersensitivity, act by blocking the open dentinal tubules. In doing so, they may influence the bond strength of the restorative resins. Thus, the aim of the study was to evaluate the effect of desensitizers on the shear bond strength of dentin adhesives and to check the extent of dentinal tubule occlusion caused by these desensitizers. Materials and Methods Sixty-four premolars were randomly divided into four groups of sixteen each. The middle depth dentin was exposed by on the buccal surface and was etched using 37% phosphoric acid and rinsed. They were assigned to, Group 1: Gluma desensitizer, Group 2: Vivasens desensitizer, Group 3: Gluma Comfort Bond and desensitizer, and Group 4: Adper Single Bond 2. Composite resin post of 2 mm in height and width were built on these specimens. The samples were then mounted in acrylic resin blocks. Universal testing machine was used to test the shear bond strength. The data were analyzed using one-way analysis of variance (ANOVA) and post hoc Tukey's test. Results The mean values of the shear bond strength were for: Group 1—18.61 ± 1.03 MPa, Group 2—17.53 ± 1.36 MPa, Group 3—22.63 ± 1.61 MPa and Group 4—23.12 ± 1.02 MPa. There was a statistically significant difference (p < 0.05) among the groups. Conclusion The use of dentin desensitizers’ influences bond strength between the tooth and the adhesive. Among the various agents, the single bottle system containing Gluma comfort bond and desensitizer had the best adhesion among the desensitizer groups. How to cite this article Patil S, Naik B, Shetty P. A Comparative Evaluation of Three Commercially Available Dentin Desensitizers on the Shear Bond Strength of Composite Resins: An in vitro Study. J Contemp Dent 2015;5(2):65-68.

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