Curve of Spee: Speed of Leveling Using Different Orthodontic Archwires

Fifty one subjects with an excessive COS were included in this study. The subjects will be randomly divided into three groups; Group one (17 patients): leveling of COS using 0.017X0.025-inch stainless steel archwire. Group two (17 patients): leveling of COS using 0.019X0.025-inch stainless steel archwire. Group three (17 patients): leveling of COS using 0.021X0.025-inch Titanium molybdenum archwire.

In the three groups, a 5mm depth reverse COS will be inserted. Records consisted of lateral cephalograms (pre-treatment, at T0 and post-treatment), peri-apical radiographs (at T0 and at T5), study casts (pre-treatment and at each time point during the tudy). Patients will be followed up on monthly visits without removing leveling archwires where alginate impressions were taken for the lower arch. Pain scores during the first week of leveling will be recorded using visual analogue scale (VAS).The amount of COS correction in mm, changes in intercanine in mm, intermolar and arch length in mm, pain scores and lower incisors root resorptions in mm will be measured.

Inclusion criteria

• Age ≥ 16 years and ≤ 30 years
• Overbite covering more than half of the lower incisor height
• Curve of Spee ≥ 4 millimeters
• Mild crowding in lower arch where non-extraction treatment is indicated.
• Normally inclined or retroclined lower incisors
• Averaged or reduced lower vertical height
• Good oral hygiene and healthy periodontium
• All permanent teeth are present except for the third molars

Exclusion criteria

• Severe crowding in lower arch where extraction treatment is indicated.
• Missing permanent molars or Premolars
• Poor oral hygiene and Periodontal disease
• Systemic health problems and medications were taken
• History of previous orthodontic treatment
• Smoking