Alterations in the mechanical properties of different brands of Nickel Titanium orthodontic archwires following their exposure to the oral environment in adult patients with moderate crowding : A Prospective Clinical Trial / By Omar Ahmed El-sayed Salama; Supervisors : Prof. Dr. Essam Nassif Professor in Orthodontics and Dentofacial Orthopedics Faculty of Dentistry Cairo University, Prof. Dr. Fouad El Sharaby Associate Professor in Orthodontics Faculty of Dentistry Cairo University, Dr. Amira Aboalnaga Lecturer in Orthodontics Faculty of Dentistry Cairo University

Supervisors : Prof. Dr. Essam Nassif Professor in Orthodontics and Dentofacial Orthopedics Faculty of Dentistry Cairo University, Prof. Dr. Fouad El Sharaby Associate Professor in Orthodontics Faculty of Dentistry Cairo University, Dr. Amira Aboalnaga Lecturer in Orthodontics Faculty of Dentistry Cairo University

Thesis (M.Sc.)--Future University in Egypt, Faculty of Oral and Dental Medicine, Orthodantics Department , 2021.

Includes bibliographical references (pages 127-148)

This present study was conducted to evaluate the change in mechanical
properties of different brands of Nickel Titanium archwires following their
exposure to oral environment.
The 117 wires were randomly divided into three groups (A), (B) and (C)
according to brand of 0.016” round NiTi archwires; each of 39 archwires.
Group A: Dentaurum
Group B: American Orthodontics
Group C: IMD Orthodontics
Each group was further subdivided into 3 different subgroups (1), (2) and
(3) according to intervention method, each of 13 archwires.
Subgroup 1 (IN VIVO): The wires were placed intraorally for 8-12 weeks
for leveling and alignment stage.
Subgroup 2 (AS RECEIVED): The wires were measured as received from
the manufacturer (negative control group).
Subgroup 3 (IN VITRO): The wires as received from the manufacturer
were placed in artificial saliva for 8 weeks (positive control).
The results of the study were:
Condition, regardless of wire brand, had a statistically significant effect on
mean plateau slope, resilience, elastic modulus.
As regards American Orthodontics wire, there was a statistically significant
increase in mean Plateau slope after storage in artificial saliva as well as a
statistically significant increase after usage in the patient’s mouth. While for
Dentaurum and IMD Orthodontics wires, there was no statistically significant
change in mean Plateau slope after storage in artificial saliva followed by a
statistically significant increase after usage in the patient’s mouth
As regards American Orthodontics as well as IMD Orthodontics wires, there
was a statistically significant decrease in mean resilience after storage in artificial
saliva as well as a statistically significant decrease after usage in the patient’s
mouth. While for Dentaurum wires, there was a statistically significant increase
in mean resilience after storage in artificial saliva followed by a statistically
significant decrease after usage in the patient’s mouth. There was no statistically
significant difference between resilience of new wires and wires used in the oral
cavity.
As regards American Orthodontics as well as Dentaurum wires, there was
no statistically significant change in mean modulus of elasticity after storage in
artificial saliva followed by a statistically significant decrease after usage in the
patient’s mouth. While for IMD Orthodontics wires, there was a statistically
significant decrease in mean modulus of elasticity after storage in artificial saliva
followed by non-statistically significant change after usage in the oral cavity.
There was no permanent deformation present in any of the samples after
comparing pre- and post-operative stereomicroscopic photographs.
In summary of the in-vitro studies, Dentaurum group showed desirable
properties such as the release of light, continuous and almost constant forces
during an extended period of activation.
Yet, the wire brand had no statistically significant effect on mean Little’s
Index, so from the clinical perspective, all the wire brands performed the same in
terms of resolution of crowding

Text in English, Abstract in English and Arabic .