Clinical Features and Dental Pathologies in Maxillary Sinus Fungal Balls and Odontogenic Sinusitis

ABSTRACT Objectives While maxillary sinus fungal balls (MSFB) can be associated with odontogenic conditions (MSFBO), MSFBO clinical and dental features have not been compared to odontogenic sinusitis (ODS). This multicenter study aimed to compare characteristics of MSFB, MSFBO, and ODS. Methods A multicenter international retrospective cohort study was conducted on adults with MSFBs and ODS who underwent sinus surgery. First in MSFBs, it was determined whether different dental conditions were more likely in FB versus non‐FB sides. Second, clinical features and dental pathologies were compared between MSFBO and ODS. For analyses, dental conditions were considered individually and as two groups: infectious pathologies and dental/oral procedures with indwelling metallic materials. Results After exclusions, there were 203 MSFBs and 163 ODS. Among MSFBs, 141 were MSFBOs. FB sides were associated with sinus protrusion of root canal treatment (RCT) materials ( p = 0.040) and dental implants ( p = 0.040). Compared to MSFBO, ODS patients were younger, more likely to have MS purulence (OR = 40.9, p < 0.010), more likely associated with apical periodontitis (OR = 2.59, p = 0.010) and oroantral fistulas (OR = 6.94, p = 0.020), and less likely associated with extruded RCT materials (OR = 0.01, p = 0.010) and protruded midface screws (OR < 0.01, p = 0.010). Comparing purulent MSFBO and ODS, ODS was more associated with infectious dental pathologies ( p < 0.009). Conclusion Compared to MSFBs, MSFBOs were associated with RCT extrusion and implant protrusion. Compared to MSFBOs, ODS was more likely purulent and associated with infectious dental pathologies. While ODS is often distinct from MSFBO, the two conditions can coexist, and surgeons must determine whether patients have infectious dental pathology requiring treatment with both conditions. Level of Evidence 4.