Orthodontic treatment with fixed appliances in particular alters the oral environment. Therefore with the establishment and increasing the complexity and variety of fixed orthodontics appliance therapy, the need and maintenance for a good oral health level has been increased, in fact the use of chlorhexidine mouth rinse has become more popular especially at the four to eight weeks of orthodontics therapy, since it has a long history as a substance for inhibiting plaque formation and reducing the number of bacteria in the oral cavity.
To investigate the effect of chlorhexidine mouth rinse 0.12% (1min. mouthrinse/12hs saliva cycle), the load deflection of straight sections from preformed round nickel titanium arch wires 0.016" (Dentaurum company) was measured with a specially designed test apparatus based on the mechanism of 3-point bend test; and the force changes of two forms of elastic ligatures (Orthomatrix USA round and square) were recorded with a modified analytical balance.
Compared with saliva; the results showed that the significant effect of chlorhexidine mouth rinse at the end of the experiment reflects the effect of time factor rather than the effect of chlorhexidine pH; since the NiTi archwire showed a non significant difference in the load deflection when compared with that immersed in a bath of saliva for the same time. Moreover chlorhexidine mouth rinse seemed to have a beneficial effect since it reduces significantly the amount of force decay of elastic ligatures despite their thickness.