Effect of orthodontic fixed appliances on epithelial cells morphology of buccal mucosa during orthodontic treatment

Abstract

the objective of this study, was to evaluate the cytometry and cytomorphology of oral mucosa epithelial cells adjacent to orthodontic attachments using exfoliative cytology. Materials and Methods. Oral epithelial cells of clinically normal buccal mucosa were obtained by exfoliative cytology from 32 orthodontic patients in three times: Day 0 (just before appliance placement), 14 and 60 days after appliance insertion. The following regions were evaluated: a) oral mucosa exposed to friction of the lower incisors brackets, b) oral mucosa exposed to friction of upper canine brackets; and c) oral mucosa exposed to friction of the upper first molar bands. Nuclear (NA) and cytoplasmic (CA) areas and NA/CA ratio were assessed by an image analysis system. Cell morphology and cellularity were also analyzed by Papanicolau technique. Mean and standard deviation were assessed for the values of descriptive statistical analysis, and evaluated by the kolmugorov Smirnov to check normal distribution of the data. The Friedman test was used to compare the cell morphology in different times, and if the differences were significant, Wilcoxon test was done. Comparing NA and CA was done by the repeated measures ANOVA, and if the difference was significant, subsequent paired t-test analysis was done. Level of significance was considered a p value equal or below 0.05. Result. The NA of the cells adjacent to orthodontic devices diminished after appliance placement. This NA reduction was insignificant in all regions and all times except in the lower incisor region that reached to its lowest level in day 60 (p < 0.001). Investigated epithelial cells showed insignificant changes in CA. Smears classified as type I according to Papanicolau, predominated in all regions analyzed, although type II inflammatory smears ,increased insignificantly after the treatment initiation. Superficial epithelial cells, were predominant cell type in day 14 and 60 in all regions, mainly in the oral mucosa in contact with the lower incisor brackets (p= 0.002). Conclusion. Preclinical alterations in the epithelial cells of oral mucosa, caused by orthodontic appliances, are reduction in NA, increase in cell keratinization and inflammatory features, especially in the lower incisor area