Proximity Differences of Maxillary Posterior Root Apices to the Maxillary Sinus Floor According to Different Skeletal Patterns: A Retrospective CBCT Study

Objectives: To evaluate the proximity of maxillary posterior root apices to the floor of maxillary sinus in Caucasian adults with different skeletal patterns using cone beam computer tomography (CBCT) images. Materials and Methods: This retrospective cross-sectional CBCT study was conducted on 90 Caucasian adults, 30 in each group of normodivergent, hyperdivergent, and hypodivergent skeletal patterns. CBCT images were obtained from one private practice in Rochester, NY. The study included Caucasian male and female adults (ages 18 years and older) with pre-treatment CBCT records of adequate quality and showing a complete maxillary sinus. Dolphin Imaging software was used to measure the distances between maxillary posterior root apices to the maxillary sinus floor. Measurements were compared based on patient age (18–36 vs. 37–56 years) and gender using the Mann-Whitney U test, and the 3 FMA, ANB, PP-FH, U6-PP, and gonial angle groups using Kruskall-Wallis followed by post hoc Mann-Whitney U two sample tests. Results: Comparing age groups, there were no statistically significant differences regarding proximity or perforation of the maxillary root apices into the sinus floor (p > 0.05). There were statistically significant differences in distances among adults with different skeletal vertical patterns (p < 0.05), with hyperdivergent subjects showing more protrusion or proximity of maxillary posterior root apices to the sinus floor, followed by normodivergent, and then hypodivergent patients. The large gonial angle group had significantly more root proximity or protrusion (p < 0.05) than did the normal and small gonial angle groups. The mesiobuccal root apices of the maxillary second molars were closest or more protruded into the inferior border of maxillary sinus, while the root apices of maxillary premolars and the palatal roots of maxillary molars were farthest or least protruded into the sinus floor. Conclusion: Although no statistical significance was found, there was a tendency for younger adults to have closer proximity or perforation of their maxillary root apices into the sinus floor than did the older age group. Adults with hyperdivergent skeletal patterns and large gonial angle exhibited a significantly greater proximity or protrusion of maxillary posterior root apices to the floor of maxillary sinus. There were differences in proximity of maxillary posterior root apices to the sinus floor, with the mesiobuccal root apices of the maxillary second molars showing the highest proximity or protrusion