A comparative study of the frictional forces between metallic bracket and ceramic bracket using conventional and unconventional elastomeric ligature

Back ground Friction is defined as the force tangential to the common boundary of two bodies in contact that resists the motion of one relative to the other. frictional forces should be kept to a minimum so that lower levels of force can be applied to obtain an optimal biological response for effective tooth movement .The most popular bracket was stainless steel which presents in the form of cast or sintered stainless steel bracket, it The main disadvantage of stainless steel bracket is the inferior esthetics Aim the purpose of this study is to evaluate the frictional forces of stainless brackets and ceramic brackets with nickel titanium (Ni-Ti) and stainless steel (St.St) arch wires using conventional elastomeric ligature (CEL) and unconventional elastic ligature (UEL). Materials and Methods The samples including pre-adjusted metal bracket pre-adjusted ceramic bracket In this in vitro study, each bracket incorporating +17 torque and +4 angulation with 0.022” x 0.028” slot diminutions. The archwires used was 0.014” super elastic nickel titanium [SE NiTi] wire 0.019” × 0.025” stainless steel [St.St.] wire. Two types of ligation were used; conventional ligation (O-Tie) and unconventional ligation The frictional forces between bracket and wire is tested in a vertical planner by a tension load using  Universal testing machine Each sample was inserted into the machine to measure the friction between wire and bracket in each case. The speed is 6mm/min and the traveling distance is 5mm. The measurements of all samples was performed under dry state Data were presented as mean and standard deviation (SD) values. One-way Analysis of Variance (ANOVA) was used for comparison between aging periods. Tukey’s post-hoc test was used for pair-wise comparison between the means when ANOVA test is significant. Student’s t-test was used for comparisons between two groups. The significance level was set at P ≤ 0.05. Statistical analysis was performed with SPSS 16.0® (Statistical Package for Scientific Studies) for Windows. Result Unconventional elastomeric ligature are able to produce significantly lower frictional forces compared with conventional elastomeric ligature (CEL) on conventionally ligated brackets the clinical advantages that arise from the use of Unconventional elastomeric ligature( UEL) is that they can be placed on every type of conventionally ligated brackets with considerable cost reduction the clinician can apply friction and low-friction mechanics simultaneously on the same archwire by using CEL and UEL only in particular segments. For example, during en masse space closure on a rectangular stainless steel archwire, UEL can be used in the posterior segments to reduce friction, while CEL is used in the anterior segment to maximize torque expression and control.