Patient-specific plates for facial fracture surgery: A retrospective case series.

OBJECTIVES: Surgeons often encounter challenges when treating maxillofacial fractures using conventional methods that involve trimming or bending ready-made titanium plates for open reduction and internal fixation (ORIF) since it can be time-consuming, imprecise, and inconvenient. This retrospective case series aimed to introduce a novel bone reduction method that utilizes virtual planning, patient-specific surgical guides, and titanium plates. METHODS: Seven patients with mandibular symphysis or subcondylar fractures resulting from facial trauma underwent cone-beam computed tomography (CBCT) or facial CT scans, and their medical histories were documented. Virtual surgery was conducted based on three-dimensional (3D) stereolithography images derived from CT scans using the FaceGide software (MegaGen, Daegu, Korea). ORIF was performed using patient-specific surgical guides and plates that were designed, printed, and milled. Radiographic, clinical, and occlusal evaluations were conducted at two weeks and six weeks postoperatively. Subsequently, 3D images from virtual surgery and postoperative CT scans were compared. RESULTS: The comparison of 3D virtual surgery and postoperative images revealed minimal surface differences of less than 1 mm. T-scan evaluations indicated that there were no statistically significant differences between the two- and six-week postoperative assessments. Favorable clinical outcomes were observed. CONCLUSION: This novel method demonstrated stable outcomes in terms of occlusion and healing, with no notable complications. Consequently, this approach may serve as a viable alternative to conventional methods. CLINICAL SIGNIFICANCE: Facial fracture surgery that utilizes patient-specific surgical guides and plates within a digital workflow can facilitate meticulous surgical planning, reducing the risk of complications and minimizing operation time.

Comparative Analysis of Three Facial Scanners for Creating Digital Twins by Focusing on the Difference in Scanning Method.

BACKGROUND: Multi-dimensional facial imaging is increasingly used in hospital clinics. A digital twin of the face can be created by reconstructing three-dimensional (3D) facial images using facial scanners. Therefore, the reliability, strengths, and weaknesses of scanners should be investigated and approved; Methods: Images obtained from three facial scanners (RayFace, MegaGen, and Artec Eva) were compared with cone-beam computed tomography images as the standard. Surface discrepancies were measured and analyzed at 14 specific reference points; Results: All scanners used in this study achieved acceptable results, although only scanner 3 obtained preferable results. Each scanner exhibited weak and strong points because of differences in the scanning methods. Scanner 2 exhibited the best result on the left endocanthion; scanner 1 achieved the best result on the left exocanthion and left alare; and scanner 3 achieved the best result on the left exocanthion (both cheeks); Conclusions: These comparative analysis data can be used when creating digital twins through segmentation, selecting and merging data, or developing a new scanner to overcome all shortcomings.

Finite Element Analysis of a New Non-Engaging Abutment System for Three-Unit Implant-Supported Fixed Dental Prostheses.

(1) Background: The stability of implants plays a significant role in the success of osseointegration. The stability of the connection between the fixture and the abutment is one of the critical factors affecting osseointegration. When restoring multiple, non-parallel, and splinted implants, achieving a passive fit can be complicated and challenging. A new EZ post non-engaging abutment system of the BlueDiamond® (BD) implant allows a wide connection angle while achieving a passive prosthesis fit. This study aimed to confirm the new abutment system's clinical applicability by evaluating its biomechanical characteristics using finite element analysis (FEA). (2) Methods: The implant-supported fixed three-unit dental prostheses model was reproduced for two groups of AnyOne® (AO) and BD implants using FEA. The loading conditions were a preload of 200 N in the first step and loads of 100 N (axial), 100 N (15°), or 30 N (45°) in the second step. (3) Results: The peak Von Mises stress (PVMS) value of the fixture in the BD group was more than twice that in the AO group. In contrast, the PVMS values of the abutment and abutment screws were lower in the BD group than in the AO group. The AO group revealed higher maximal principal stress (MPS) values than that of the BD group in the cortical bone, cancellous bone, and crown. The average stress of the outer surface of the abutment was lower in the AO group than in the BD group. The stress distribution for the inner surface of the fixture confirmed that the BD group displayed a lower stress distribution than the AO group under axial and 15° loads; however, the average stress was 1.5 times higher at the 45° load. The stress values of the entire surface where the cortical and cancellous bone were in contact with the fixture were measured. The AO group showed a higher stress value than the BD group in both cortical and cancellous bone. (4) Conclusions: In the AO group, the PVMS value of the fixture and the stress distribution at the contact surface between the fixture and the abutment were lower than those of the BD group, suggesting that the stability of the fixture would be high. However, due to the high stress in the fastening area of the abutment and abutment screw, the risk of abutment fracture in the AO group is higher than that of the BD group. Therefore, the new EZ post non-engaging abutment of the BD implant can be used without any problems in clinics, similar to the non-engaging abutment of the AO implant, which has been widely used in clinical practice.