Nano-Crystalline Ceramic Coating of Orthodontic Archwires

Purpose: The project aims to assess if hard ceramic coatings on orthodontic archwires will reduce the sliding resistance of archwires in the brackets during orthodontic treatment procedures.

Participants: Up to 80 subjects will be recruited for this study. Subjects between 10 years of age and 45 years old will be otherwise healthy subjects previously diagnosed with malocclusion.

Procedures (methods): Each subject will receive an experimental (coated) or a regular (uncoated control) orthodontic archwire (AW) for a 3-month treatment. The 3D digital images of each subject's dentition will be recorded three times at 0-, 6- and 12-week visits. The AW will be removed and retrieved after the 3-month trial.

In this trial, nano-crystalline ceramics will be applied to the surface of orthodontic archwires using ion beam assisted deposition to reduce sliding resistance. Excessive sliding resistance works against tooth motion as the bracket slides along the wire into a new position. These ceramic coatings will produce more predictable outcomes, requiring less force and shorter treatment time. A limited clinical trial will be conducted to demonstrate these effects.

The aim of this project is to assess the clinical efficacy of the new archwires in Stage 1 (leveling and aligning) and Stage 2 (space closure) of orthodontic treatment using a twin bracket. The working hypothesis is that reduction of sliding resistance in bracket-wire interfaces will allow effective tooth movement in leveling, aligning, and sliding, while minimizing unwanted tooth movement such as lateral (mesio-distal direction) movement due to friction. This will be tested in a total of 80 patients who are undergoing active treatment in the University of North Carolina (UNC) orthodontic graduate clinic. These patients will be comprised of a treatment group (coated) and a control group (uncoated) of 20 each in Stage 1 and Stage 2 treatment.

A successful program will demonstrate a clinically significant increase in the amount and rate-of-change of tooth movement in leveling, aligning, and sliding teeth.

Eligibility Criteria:
Inclusion Criteria:

In the initial or second stage of active treatment at the University of North Carolina graduate orthodontic clinic

Specific inclusion criteria for 1st order tooth movement:

1. Non-extraction treatment in mandible
2. Mandibular Little Index greater than or equal to 5 mm
3. Presence of all permanent anterior teeth
4. Age 10-45 years
5. Consent to participate in the study

Specific inclusion criteria for 2nd order tooth movement:

1. Space closure treatment need greater than or equal to 3 mm (extraction and/or non-extraction patients)
2. Space closure being carried out via sliding mechanics using power chains, spring coils, or interarch elastics
3. Age 10-45 years
4. Consent to participate in the study

Exclusion Criteria:

Specific exclusion criteria for 1st order tooth movement:

1. Systemic diseases such as diabetes, hypertension, temporomandibular disorders (TMD), craniofacial syndrome, etc.
2. Subjects who have incisor mandibular plane angle (IMPA) greater than or equal to 100 degrees
3. Anterior tooth completely blocked from the arch form
4. Periodontal pocketing of any lower anterior teeth greater than 4 mm

Specific exclusion criteria for 2nd order tooth movement:

1. Systemic diseases such as diabetes, hypertension, TMD, craniofacial syndrome, etc.
2. Space closure being carried out via closing loops
3. Periodontal pocketing greater than 4 mm