Table 1 Assignment of variables

Cyst or not

0 = no cysts, 1 = with cysts

Gender

0 = female, 1 = male

Age

0 = ≥ 18 years, < 35 years; 1 = ≥ 35 years, < 53 years; 2 = ≥ 53 years

Dental condition

0 = dentate, 1 = partially edentulous, 2 = completely edentulous

Pulp condition

0 = healthy tooth, 1 = with deep caries or treated deep caries

2 = having endodontic lesions or having undergone endodontic treatment, 3 = having apical lesions

Periodontal condition

0 = normal to mild periodontitis (< 15% bone loss)

1 = moderate periodontitis (bone loss ≥ 15%; ≤33%), 2 = severe periodontitis (bone loss > 33%)

Maxillary sinus different sides

0 = left side, 1 = right side

Relationship of the tooth root to the floor of the maxillary sinus

0 = no contact, 1 = at least one root in contact with sinus floor

Morphology of the floor of the maxillary sinus

0 = flat maxillary sinus floor, 1 = uneven or separated maxillary sinus floor

Vessels of the lateral wall of the maxillary sinus

0 = no blood vessels in the lateral wall of the maxillary sinus, 1 = blood vessels in the lateral wall of the maxillary sinus

Mucosal condition of the maxillary sinus

0 = no mucosal thickening (mucosal thickness less than 2 mm)

1 = with mucosal thickening (mucosal thickness greater than 2 mm)

Presence of maxillary sinusitis

0 = without maxillary sinusitis, 1 = with maxillary sinusitis

Development of the maxillary sinus

0 = normal maxillary sinus development, 1 = maxillary sinus hypoplasia

Cortical bone condition of the floor of the maxillary sinus

0 = cortical bone at the floor of the maxillary sinus is intact, 1 = cortical bone at the floor of the maxillary sinus is incomplete