Maryam Omidkhoda - Associate Professor of Orthodontics, Dental Materials Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
Mahboobe Dehghani - Assistant Professor of Orthodontics, Dental Research Center, School of Dentistry, Mashhad University of Medical Sciences, Mashhad, Iran
Nooshin Mohtasham - Professor of Oral and Maxillofacial Pathology, Dental Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
Hamed Sadeghian - Pathologist, Clinical laboratory department, Imam Reza hospital, Mashhad University of Medical Sciences, Mashhad, Iran.
Elham Malle - Dentist, private practice

Introduction: The use of acrylic appliances in the oral cavity warrants biocompatibility evaluation. This study aimed to carry out an in vivo investigation of the cytomorphometric changes of oral mucosa among children undergoing acrylic removable orthodontic appliances. Methods: In this observational clinical study, acrylic removable orthodontic appliances were delivered to ۲۵ orthodontic patients and followed for ۳ months. Mucosal samples were collected by gentle brushing of the internal part of the right and left buccal mucosa before appliance delivery (T۰) and ۱ week (T۱), ۱ month (T۲), and ۳ months (T۳) following appliance delivery. The cells were immediately prepared for cytomorphometric analysis. Results: There was no significant difference in the nuclear area between different time intervals. Cytoplasmic area in the right side of the buccal mucosa was significantly larger ۱ month following appliance delivery (T۲), compared to T۰ (P=۰.۰۱۸) and T۱ (P=۰.۰۳۶). On the right side, nuclear to cytoplasmic ratio values in T۲ were significantly less than those in T۰ (P=۰.۰۰۸) and T۱ (P=۰.۰۰۲). Moreover, T۳ values were lower than T۱ values (P=۰.۰۴۸). The results of micro-nucleation and apoptosis analysis did not show statistically significant differences between different time intervals. Conclusion: Orthodontic acrylic appliances may not be a factor in inducing morphologic changes of oral mucosa cells; nevertheless, they may promote some transient cytometric effects. It seems that they do not cause any significant damages to the oral mucosa in long term.

Acrylic resins, Cytotoxicity, Orthodontics