Incidence of Sinus Membrane Thickening and Association With Unhealthy Teeth: a Retrospective Review of 831 Consecutive Cone Beam Scans

Michael S. Block DMD, Private Practice, Metairie, LA
Kamran Dastoury DDS, MD, Oral and Maxillofacial Surgery, LSU School of Dentistry, Metairie, LA
The use of cone beam scanning to determine bone availability for dental implants allows cross section visualization of the posterior maxilla and maxillary sinus (1,2).  The purposes of this retrospective review of cone beam scans is to: (1) determine the incidence of sinus membrane thickening in a consecutive series of patients; (2) identify the incidence of  healthy or unhealthy teeth and sinus membrane thickening; and (3) document the reaction of the sinus membrane thickening after unhealthy teeth are removed.

Methods:  Consecutive patients had cone beam scans examined and the sinuses graded. Grading Criteria - 1: 0 to < 2 mm  membrane thickening; 2: 2-5 mm thick membrane; 3:  membrane  >5 mm to level of  ostium; and 4: the was obliteration above the ostium.  The cross sections were examined using software by the manufacturer of the cone beam.  An unhealthy tooth had periapical lesions, osteolysis, or extensive caries with bone loss. The examiner used a standardized approach in viewing the CBCT scans. The splines were aligned to the canals of the teeth, with the horizontal spline at the level of the alveolar crest. Measurements were from the lowest aspect of the bony sinus floor to the maximum height of membrane thickening  above the tooth furcation.  When needed, adjacent structures such as the cemento-enamel junction (cej) of the adjacent teeth were used to measure the thickness of the sinus membrane on follow up scans.  If there were no adjacent teeth present, the reference was the inferior level of the nasal turbinate.  Intra-examiner error was determined by evaluating membrane thicknesses on six patient scans at three separate sessions examiner KD. The standard deviation was 0.64 mm, ranging from 1.5 mm to 0.05 mm. 

 Results: 831 patients (mean age 52, range 9 to 101) had 1662 sinuses evaluated. Patients referred to this private oral surgery practice were found to have an incidence of 46.7% (388 patients) with thickening of their sinus membranes and 30.1% (469) of all sinuses evaluated  The incidence of patients and  sinus membrane thickening according to our grading criteria was grade 2 = 36.8% patients/24.3% sinuses; grade 3 = 6.0% patients/3.7% sinuses, and grade 4 = 3.6% patients/2.2% sinuses. Unilateral sinus disease was predominant.

Of those sinuses with thickening, 80.6% were grade 2, 12.2% were grade 3, and 7.2% were grade 4.  Of the 469 sinuses with membrane thickening, 210 were adjacent to unhealthy teeth , 233 were adjacent to healthy teeth, and 26 were in edentulous maxillas.   Of the 210  unhealthy teeth , 30 had post-extraction cone beams available for evaluation.  The grade 2 sinus membrane thickening showed a 75% resolution to grade 1 after adjacent tooth removal.  The grade 3 sinuses resolved 25% to grade 1 and grade 2, with 50% remaining at grade 3.  There were 2 grade 4 sinuses with followup scans with 1 resolving to grade 2 and the other remaining at grade 4.

Conclusions: Sinus membrane thickening is present in 46.7% of patients coming to an Oral and Maxillofacial Surgery practice. The incidence of sinus membrane thickening was almost equal in association with unhealthy or healthy teeth. The removal of the  unhealthy teeth decreased but did not completely resolve sinus membrane thickening. 1. Nair UP, Nair MK. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 110:e53-57, 2010. 2.  Pokorny A, Tataryn R.. Int Forum Allergy Rhinol. 3:973-979, 2013