Maxillary Sinus Differs Among Vertical Patterns of Class II Populations

Abby L. Syverson

Syverson, Abby L1, Proskurnin, Evgenii1, Boucher, Normand1, Mupparapu, Mel2, Chung, Chun-Hsi1, Zou, Min3, Li, Chenshuang1
1University of Pennsylvania School of Dental Medicine, Department of Orthodontics
2University of Pennsylvania School of Dental Medicine,Department of Oral Medicine
3College of Stomatology, Xi'an Jiaotong University, Department of Orthodontics


The proximity of the maxillary sinus to posterior teeth is an important consideration for orthodontic treatment, particularly with the advent of TADs. The sinus can limit the placement of TADs themselves or could interfere with tooth movement, including posterior intrusion and distalization often prescribed in high angle class II patients. This study aims to determine how the morphology of the maxillary sinus varies in different Class II vertical skeletal patterns.


Preorthodontic treatment CBCTs of skeletal Class II Asian and Caucasian population (15-40 years old) were obtained from the database of patients seeking orthodontic treatment (IRB number: 843465 for Caucasian population, xjkqll[2020]No.014 for Chinese population). The volumetric size of the sinus was computed, as was the height, width, and length. The distance from the posterior teeth root apices to the sinus floor was recorded. The alveolar width and height surrounding the posterior maxillary dentition were also measured.


High angle samples have significantly larger sinus volume, height and width compared to normal angle samples. The molars in high angle samples protruded more into the sinus than that in normal angle samples. The alveolar bone width is similar between the groups at 5 mm apical to bone crest, while at 8 mm and 10 mm apical to the bone crest, Class II high angle samples tend to have thinner alveolar bone between the maxillary first and second molars compared to normal angle samples.


High angle patients have a larger sinus size, greater root protrusion into the sinus, and less alveolar bone for TADs placement compared to normal angle patients.