Inlfuence Of Various PH And The Treating Time On Surface Friction Of Ni-Ti Orthodontic Wire

Objective: To measure the friction changing of nickel-titanium (Ni-Ti)orthodontic wires in different pH value by universal machine, and to discuss theinfluence of nickel titanium arch wires friction in different PH and different treatingtime.Methods: About3cm segments were obtained from two terminals of LH, OT,CuNiTi,IMD(T)IMD(super elastic),OT(T),Suhang,Youyan,Smart rthodontic arch wiresrespectively, maintained in EP resin tube containing artificial saliva(pH=4.0,pH=6.75,1mL),and cultured at37℃. The friction was measured by universial machine after1,7and28days.Results:1. Nine different brands of nickel-titanium wire were treated in differenttime.PH was inversely proportional to the friction in wire.Time was directlyproportional to the friction.2. Friction in9brands of niti wire in two different ph value and observation indifferent days is given below.PH=4.0PH=6.75friction friction1DAY SH>IMD(super)>OT(super)>SH>OT(super)>IMD(super)>IMD (T)> YY> cuniti> OTsmart> YY> OT (T)> IMD(hot)> Smart> LH(hot)> Cuniti> LH28DAY SH> IMD (super)> IMDSH>IMD(super)>OT(T)>OT(super)>Smart>YY>(super)>IMD(T)>OT(T)>Cuniti> OT (T)> LHYY> Smart> Cuniti> LH3. Consequently when the ph value is decreased from6.75to4.0the friction of thewire increases.increase in SH is7.03N,IMD(TA)is5.03N.These brand have greatestimpact by the PH.whereas in LH、OT、Cuniti the friction increase is small.Rate of increase of friction in LH wire is smallest with the value of2.35N.Conclusion:1.Different pH values under different soaking time, nine kinds of nickel-titaniumarch wire surface friction change.2.As the PH value increase the friction of the9brands of niti wire decreases. Asthe immersion time increases friction also increase.The most obvious impact is seenwith SH and IMD(super elastic)and least affected is LH brand.3.Role of acidic artificial saliva and immersion time will lead to the corrosion ofsurface of niti wire ths increasing the friction.As the ph is reduced and immersion timeis more severe leading to more friction hence greater force.4. by measur the LH the the initial friction lowest speed Airlines maximumfriction.