December’s Tip

    Step-in and step-out refers to the distance of the bracket slot from the tooth surface in a horizontal plane. Due to the difference in the thickness of teeth, certain teeth are stepped out in relation to the other teeth. For example, in the maxilla; central incisors are stepped-out, lateral incisors are stepped-in, cuspids are stepped-out, etc. However, this is all built into the brackets in preadjusted SWA. Therefore, certain brackets are thicker than others and maxillary molars have 10° – 15° distal offset.

Ribbon arch pliers are used for the First and Second order artistic wire bends, and the arch wire of choice is a .016 x .025 SS (1,700 gm of force). Certain educators prefer a .019 x .025 CNA (Beta titanium) or a .019 x .025 Multibrade. However, the author found that Stainless Steel is more resilient; it maintains the crisp artistic wire bends better and it can be retained as the final arch wire.

The orientation of the Ribbon arch pliers is perpendicular to the arch wire. The basic rule of First order artistic wire bends is:

1. If the side of the crown of the tooth should be stepped-out – bend-in the arch wire
2. If the side of the crown of the tooth should be stepped-in – bend-out the arch wire
3. All artistic wire bends are around 15°, except maxillary molars 25° (distal offset)

These artistic wire bends may be accentuated on subsequent appointments.

             A misaligned mandibular right lateral was attempted to correct by placing a 15° mesial step-out; however, the tooth did not align properly. Therefore, we placed a 15° distal step-in and the problem was resolved in one month.  This double First order artistic wire bend is referred to as “Z” bend.  Now, there are two choices:

1. Maintain the same arch wire for 3 months and finish the case, alternatively;
2. Place a heavier finishing SS arch wire (i.e. a .018 x .025 or a .019 x .025). However, both first order artistic wire bends must be meticulously reproduced and held for additional 2 months

References

1. Nakajima E., Manual of Wire bending Techniques; 56 – 65
2. Rondeau Seminars “Case Finishing” manual; 64 – 80
3. Andrews L. A.; Straight Wire the Concept and Appliance