Background: To evaluate the root anatomy, root canal morphology and the anatomical relationship between the roots and maxillary sinus of maxillary second premolars by CBCT in a western Chinese population. Methods: A total of 1118 CBCT scans of the maxillary second premolars were collected from West China Hospital of Stomatology, Sichuan University. Information below were measured on axial, coronal and sagittal sections, recorded and evaluated properly: the number of roots and canals, the morphology of canal system classified by Vertucci standard, the inter-orifice distance of canal orifices, the curvature of each canal and the distance from root tip to maxillary sinus floor. Results: Among the 1118 teeth, 94.2% (1053) are single-rooted and 55.1% (616) have one canal. Type I (55.1%) is the commonest root canal morphology followed by Type II (31.9%). The mean inter-orifice distance (IOD) for multi-canal teeth ranging from 2.72 ± 0.32 to 3.41 ± 0.11 mm. Of 1622 canals, 38.8% (630) curvature are mesiodistal and 30.9% (501) are straight canals. The distance from root tip to maxillary sinus floor increased with age and the mean distance of single-rooted ones is 2.47 ± 3.45 mm. Conclusions: All kinds of canal morphology category can be detected in maxillary second premolars. The IOD might be a predictable factor for root canal morphology. Roots of maxillary second premolars are related to maxillary sinus which should be treated carefully.

Objective: The objective of this study was to assess the diagnostic efficacy of dynamic high-resolution ultrasonography (HRUS) in detecting anterior disc displacement with reduction (ADDWR) and anterior disc displacement without reduction (ADDWoR) in the temporomandibular joint (TMJ). Methods: A total of 144 TMJs was categorized into three groups according to the magnetic resonance imaging (MRI) findings, which served as the reference standard: the normal disc position (NDP) group, the ADDWR group, and the ADDWoR group. Static images of the TMJ in full opening and maximum intercuspal positions, along with dynamic sequences during jaw opening, were obtained utilizing a 14 MHz L-shaped linear array transducer. The diagnostic efficacy of dynamic HRUS for identifying ADDWR and ADDWoR was evaluated in terms of accuracy, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), diagnostic odds ratio (DOR), and the Youden index. Results: According to the MRI findings, the NDP, ADDWR, and ADDWoR groups consisted of 42 (29.2%), 47 (32.6%), and 55 (38.2%) TMJs, respectively. HRUS data revealed 54 TMJs (37.5%) in the NDP group, 26 TMJs (18.1%) in the ADDWR group, and 64 TMJs (44.4%) in the ADDWoR group. With MRI as the reference standard, HRUS exhibited a diagnostic accuracy of 71.4%, sensitivity of 51.4%, and specificity of 91.4% for ADDWR. For the ADDWoR, HRUS attained a diagnostic accuracy of 86.5%, sensitivity of 90.0%, and specificity of 82.1%. Conclusions: With MRI serving as the reference standard, dynamic HRUS has high diagnostic value for ADDWoR, with better diagnostic accuracy than ADDWR. Ultrasonography has the potential to be used as a highly effective and non-invasive imaging modality for the early screening of ADD in future clinical practice.

This report describes maxillary antral pseudocyst drift after maxillary sinus floor augmentation through osteotome sinus floor elevation with simultaneous implant placement. 3D Slicer was used to measure the pseudocyst and maxilla for the placement of the implants; follow-up visits were scheduled at 6, 12, and 22 months. No adverse effects were observed during or after surgery, and all implants exhibited osseointegration without mobility. At 6 months after surgery, the pseudocyst had moved posterolaterally from the preoperative position near the anterior medial maxillary sinus, then returned to its original position at 12 months. However, it had remigrated to the posterolateral position at 22 months. The preoperative volume of the pseudocyst was 3.795 mm³; it was 2.370, 3.439, and 2.930 mm³ at 6, 12, and 22 months after surgery, respectively. The changes in pseudocyst drift and volume did not have a substantial negative influence on the implants, presumably because of cystic attachment and the recurrence of multiple pseudocysts at different locations. The risks associated with changes in a pseudocyst can be avoided, if an appropriate treatment plan is selected.