Shear bond strength and antibacterial effects of orthodontic composite containing TiO2 nanoparticles

Abstract

Nanofillers can reduce enamel demineralization without compromising physical properties of the composite. The aim of this study was to evaluate shear bond strength (SBS) and antibacterial effects of an orthodontic composite after adding titanium oxide (TiO2) nanoparticles. Light cure orthodontic composite paste (Transbond XT) was blended with TiO2 nanoparticles. A total of 30 extracted premolars were randomly allocated into two groups of 15. In order to bond brackets, Transbond XT adhesive and nanocomposite were used in each group, respectively. SBS of two groups were determined, and the adhesive remnant index (ARI) scores were assessed. A total of 45 composite discs specimen were prepared. Of the 45 discs, 30 discs were made from nanocomposite and tested for antibacterial properties immediately and 30 days after curing by direct contact test. The antibacterial properties of the remaining 15 discs that were made from the conventional composite were tested immediately after curing as control group. Student's t-test and chi-square tests were used to analyse the data with the significance level of 0.05. No significant difference was found between SBS of conventional and nanocomposites, 24 hours after curing (P = 0.58). Chi-square test showed that ARI scores of two groups were not significantly different after debonding (P = 0.69). Comparison of antibacterial effects between conventional and nanocomposite demonstrated significant difference between two groups, with nanocomposites having a higher antibacterial activity (P = 0.03). Colony count revealed no significant difference in bacterial growth immediately and 30 days after curing in nanocomposite group. Adding TiO2 nanoparticles to orthodontic composite enhances its antibacterial effects without compromising the SBS.

Comparative evaluation and influence on shear bond strength of incorporating silver, zinc oxide, and titanium dioxide nanoparticles in orthodontic adhesive

“…[15] Incorporation of TiO 2 nanoparticles to dental composites also augmented mechanical properties, such as modulus of elasticity, microhardness, flexural strength, and also provided bond strength values that similar or even higher levels than that of the controls not containing the nanoparticles. [16] It has been mentioned in literature that various bonding manners need to confirm the prerequisites of the normal SBS ranging from 5.9 to 7.8 MPa. [17]…”

Effect of enamel protective agents on shear bond strength of orthodontic brackets

“…These included the use of glass ionomer cement [10,11], topical applications of preventive agents as fluoride and casein phosphopeptide-amorphous calcium phosphate [12,13], antibacterial agents incorporated in the adhesive resin [14,15], fluoride releasing adhesives [16,17], caries infiltration resins [18,19], laser irradiation [20,21], bioactive glass-containing adhesives [22], and enamel deproteinizing agents [23]. …”

Effect of methacrylated-based antibacterial monomer on orthodontic adhesive system properties

“…Seeking the improvement of orthodontic adhesives, some authors have performed studies using different antibacterial agents such as MDPB, 3 chlorhexidine, 4,5 nanoparticle silver, 6 triclosan, 7 zinc oxide, 8 titanium dioxide, 9 and others. A reduction in bacterial growth is observed with a decrease in the adhesive's properties, such as lower bond strength.…”