Purpose of the study: The aim of the current study was to evaluate the vertical and horizontal relationships between the root apices of maxillary molars and the maxillary sinus floor (MSF). And to examine the Intra- and Interobserver reliability of this assessments.
Materials and methods: This retrospective study was conducted at Taibah University Dental College & Hospital. We evaluated the vertical and horizontal relationships between the root apices of maxillary molars and the maxillary sinus floor according to modified classification from Kang et al. 2015 study. Kappa agreement coefficient was calculated to examine the intraobserver and interobserver reliability. Frequency and proportions were tabulated, and Generalized Estimating Equation (GEE) model analysis was performed for the test of significance.
Results: The sample contained 216 maxillary molars in total, with 56 missing molars, the analysis was performed on 160 maxillary molars. Kappa agreement coefficient was 0.9857 for intraobserver reliability and were 0.9799 and 0.9803, respectively for interobserver reliability. Concerning vertical measurements, the highest frequency was found in group two (58.8%) where there was close contact between maxillary molar root apices and MSF. For the horizontal relationship, most teeth were in the second group where the MSF is centrally located (37.5%).
Conclusion: Our study showed that most of the maxillary molars in our sample had close contact with floor of the maxillary sinus which was centrally located in most of our cases. Also, our study stated that the assessment classification was highly reliable that greatly will assist the clinician to relay on for the assessment and preceding knowledge of relationship between maxillary molars and maxillary sinus floor before any surgical dental procedures which is valuable for preoperative treatment planning and the inhibition of complications.