MULTIFLEX VERSUS SUPERELASTIC - A RANDOMIZED CLINICAL-TRIAL OF THE TOOTH ALIGNMENT ABILITY OF INITIAL ARCH WIRES

Two arch wires commonly used for initial tooth alignment were compared with regard to their clinical effectiveness. The two arch wires teste d were 0.0155-inch diameter multiple-stranded stainless steel wire (De ntaflex, Dentaurium, Optident, Yorkshire, England) and 0.014-inch diam eter nickel-titanium alloy wire (NiTi, ORMCO Co., Monrovia, Calif.). C onsecutive patients attending an orthodontic clinic for routine placem ent of a fixed appliance were randomly assigned one of these two initi al arch wires. Good quality alginate impressions of the appropriate de ntal arch were taken before arch wire placement and also at the subseq uent appointment, which was, on average, 6 weeks later. Seventy-four a rches were used in this study. The degree of tooth alignment achieved for each wire type was compared with a Reflex Microscope (Reflex Measu rement Ltd., Butleigh, England) to make detailed measurements on the r esultant casts. The degree of initial alignment achieved with the two wires was similar over this g-week period. However, some differences w ere found for the lower labial segment where the interbracket span is usually reduced and where the superelastic nickel-titanium wire was fo und to give improved alignment. No threshold of crowding was found whe re one arch wire performed better than the other.