Effects of Storage and Loadcycling on SBS of Orthodontic Composites

Methods: According to the manufacturer′s recommendation, the four different orthodontic composites (Transbond XT™, Light Bond™, Bisco Ortho™, Kurasper F™) were used to bond brackets (3M Unitek™) to 96 human maxillary premolars. All specimens divided in eight groups and were stored in artificial saliva at 37°C for 30 months. After storage period, mechanical loading (50000 times) was performed to four groups of the specimens for aging. Brackets were debonded using a universal testing machine (TSTM 02500, Elista Corp., Istanbul,Turkey) for SBS testing. SBS values were recorded in Newton and converted to Mega Pascal (N/mm2). Statistical analysis was performed by one-way analysis of variance (ANOVA) and Tukey's HSD tests.

Results: Bisco Ortho LC™ composite, which compared before and after mechanical loading in SBS value decreased statistically significant differences (p<0.05). However, there were no statistically significant differences among the orthodontic composite types in SBS value (p>0.05).

Conclusions: Although SBS value of orthodontic composites affected from the mechanical loading, this sitiuation may not be important for the success of bonding.