Panoramic Radiographic Evaluation of the Influence of Maxillary Sinus on Orthodontic Tooth Movement

Abstract

Objectives: To investigate the influence of maxillary sinus on orthodontic tooth movement evaluated with panoramic radiographs. Methods: The pre-treatment panoramic radiographs from 312 consecutively treated orthodontic patients were screened. The selection criteria were as follows: (1) Group A, the roots of posterior teeth were in close proximity to the maxillary sinus, which was in category 4 according to the classification suggested by Sharan et al. (2) Group B, the roots of posterior teeth were away from the maxillary sinus, which was in categories 0 or 1 according to the same classification. (3) Either upper first or second premolars were extracted for orthodontic purpose. (4) Post-treatment panoramic radiographs had been taken. By evaluating the pre- and post-treatment panoramic radiographs, the intra- and inter-group changes in the angle formed by the upper first molar and adjacent premolar (MP angle) were analyzed using Student’s t-tests. Results: One hundred thirty cases were selected (65 in each group, 47 males and 83 females, mean age 20.38 ± 4.72 years). Prior to the orthodontic treatment, there was no significant difference in the MP angle between group A and B (p > 0.05). After treatment, the MP angle changed from 3.15° ± 6.89° to -0.88° ± 5.60° (p < 0.05) in Group A, and from 4.75° ± 6.07° to 0.85° ± 7.11° (p < 0.05) in Group B. However, there was no significant difference between the changes in two groups. Conclusions: The result of this study showed that the parallelism of the molars and adjacent premolars was improved, regardless of the proximity of the sinus to the roots of adjacent teeth, which implied that the maxillary sinus would not hinder the orthodontic root movement.