Volumetric Assessment of Maxillary Sinus Using CBCT in Relation to Sinonasal Anatomic Variations in an Iraqi Population.

BACKGROUND

Maxillary sinus volume (MSV) influences sinus floor elevation, dental implant planning, and rhinologic decision-making. Anatomic variants [nasal septal deviation (NSD), concha bullosa (CB), maxillary sinus septa (MSS)] and mucosal thickening (MT) may alter aeration/ventilation and, consequently, MSV; prior reports are mixed.

OBJECTIVE

To compare MSV among normal, NSD, MSS, inferior concha bullosa (ICB), and mucosal thickening (MT >2 mm) groups in an Iraqi CBCT cohort.

DESIGN SETTING

PARTICIPANTS

A retrospective cross-sectional study of 200 adult CBCT scans obtained for dentomaxillofacial indications (2020-2025) at a tertiary center in Baghdad (5 independent groups; n=40 each). Reporting follows STROBE guidelines.

METHODS

Bilateral MS were segmented in OnDemand3D and averaged per subject (cm3). Assumptions were checked (Shapiro-Wilk; Levene). Given non-normality and heteroscedasticity, Welch ANOVA was the primary test; Games-Howell handled pairwise contrasts; Dunnett (two-sided) compared each variant versus normal. Effect sizes: partial η2, ω2, and Hedges g (95% CI).

RESULTS

Assumptions were violated (Shapiro-Wilk P<0.05 in 4/5 groups; Levene P<0.001). Welch ANOVA showed a large between-group effect [F(4,≈96.41)=45.85, P<0.001; η2≈0.468; ω2≈0.456]. Mean MSV (cm3): ICB 15.05, MSS 14.17, normal 13.95, NSD 13.08, MT 12.08. Games-Howell: ICB>all and MT<all (all P<0.001); NSD<normal (Δ=0.88 cm3, P=0.003); MSS≈normal (Δ=0.22 cm3, P=0.91). Largest standardized contrast: ICB versus MT g=2.50.

CONCLUSIONS

In this Iraqi CBCT cohort, ICB presented the largest MSV and MT the smallest; NSD showed a modest reduction versus normal, while MSS did not differ. A ventilation-pathway model (ostium/infundibulum geometry and mucosal disease) better explains volume differences than variant labels alone.