Introduction:

Dental caries, a chronic disorder, is defined as a disease that causes a shift in the bio-film towards ac-id-producing microbes, eventually culminating in mineral loss from hard dental tissue. The standard method of treating deep cavities involves completely removing all carious dentin.

Objectives:

The aim of the present study was to evaluate and compare the shear bond strength to dentin of Thera­Base and composite resin using self-etch and total-etch adhesive systems.

Material and methods:

Forty-five extracted maxillary premolars were stored in saline solution and divided into 3 groups: Group 1 – TheraBase; Group 2 – composite resin (3M, ESPE Filtek Z350XT, USA) using etch-and-rinse (Adper™ Single Bond 2/Plus; 3M, ESPE, USA); and Group 3 – composite resin using self-etch (Single Bond Universal Adhesive; 3M, ESPE, USA) protocols. Dentin from buccal surface was exposed using tapered fissure diamond point to a depth of 2 mm. A cylindrical projection of TheraBase and composite resin (4 mm height, 1.8 mm width) was made with silicon moulds from the surface of dentin. Shear bond strength was tested using universal testing ma-chine (ACME Engineers, India), with a crosshead speed of 0.5 mm/min. Data obtained were statistically analyzed using IBM SPSS version 21.0 and independent t-test.

Results:

Group 3 (24.34 Mpa) presented significantly higher shear bond strength when compared with group 2 (21.02), followed by group 1 (9.52 MPa) (p < 0.05).

Conclusions:

Shear bond strength of TheraBase was lesser than composite resins bonded with etch-and-rinse and self-etch bonding agents. However, shear bond strength of TheraBase is acceptable when used as a base under direct composite restorations.