On the morning of Thursday, 25 June 2026, the College of Dentistry, University of Mosul, held the public defense of the PhD dissertation entitled:
“Local Administration of Nandrolone Decanoate and the Local Application of Bone Stimulation Device for Enhancement of Tooth Stability after Orthodontic Tooth Movement (Rabbit Model Study)”
submitted by the PhD candidate Mr. Omar Hussein Hasan Al-Luwaizi.

The dissertation addressed orthodontic relapse, one of the most complex and multifactorial challenges in orthodontics. The study aimed to evaluate the effects of the local application of Nandrolone Decanoate and the Exogen® Bone Stimulation Device on alveolar bone remodeling and the preservation of periodontal ligament integrity, with the ultimate goal of reducing the incidence of orthodontic relapse.
The experimental study was conducted on 45 adult albino rabbits, which were randomly allocated into three groups: a control group, a Nandrolone Decanoate group, and an Exogen device group. Orthodontic movement of the mandibular incisors was induced for two weeks, followed by a three-week retention period during which the assigned local treatments were administered. This was followed by relapse periods of varying durations (0, 10, and 20 days) to facilitate the required histological and radiographic assessments.
The findings demonstrated that the Exogen device group significantly outperformed the other groups in stimulating new bone formation, increasing bone density, and enhancing angiogenesis during the intermediate and late phases of the study. In contrast, the Nandrolone Decanoate group exhibited superior bone density during the early and late phases and showed a greater periodontal ligament width compared with the control group, which recorded the highest number of osteoclasts.
The researcher concluded that the use of the Exogen Bone Stimulation Device achieved superior outcomes in bone regeneration, improved the health of the tooth-supporting tissues, and reduced bone resorption—particularly in the cervical half of the alveolar bone. These findings contribute to improving tooth stability within the alveolar socket and reducing the rate of orthodontic relapse over time.
The dissertation was examined by the following committee members:
Professor Dr. Neam Fakhri Yaseen – Chairperson (Al-Noor University / College of Dentistry)
Professor Dr. Mahmood Ahmed Hammood – Member (University of Mosul / College of Science)
Professor Dr. Ghada Abdulrahman Abdullatef – Member (University of Mosul / College of Dentistry)
Assistant Professor Dr. Khawla Mohammed Aouni – Member (University of Mosul / College of Dentistry)
Assistant Professor Dr. Enas Talib Mohsin – Member (University of Mosul / College of Dentistry)
Assistant Professor Dr. Sarmad Subhi Salih – Member and Supervisor (University of Mosul / College of Dentistry)
Assistant Professor Dr. Ahmed Khalaf Ali – Member and Supervisor (University of Mosul / College of Veterinary Medicine)
At the conclusion of the defense, the dissertation was approved subject to the incorporation of the required revisions.