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Background The aim of this study was to compare the accuracy of 3D-printed intermediate wafers (3DW) with conventionally made intermediate wafers (CW) fabricated through manual model surgery (MMS). This study was designed as an in vitro experiment focused on the Le Fort I osteotomy and maxillary repositioning process. It aims to achieve maxillary repositioning outcomes mediated by intermediate wafers while eliminating intraoperative errors. Materials and methods Both MMS and virtual model surgery (VMS) were performed for each patient to fabricate CW and 3DW. Subsequently, the maxillomandibular dental casts were remounted on the articulator using the fabricated CW and 3DW, followed by digital scanning and superimposition. The midpoint of the right maxillary central incisor edge, the uppermost points of the right and left maxillary canines, and the mesiobuccal cusps of the right and left maxillary molars were used as measurement points. The points in VMS were set as references for comparison. Paired t -tests were conducted to compare the outcomes between CW and 3DW. Independent t -tests were used to analyze differences between groups with and without rotational movements. Additionally, Spearman’s correlation analysis was performed to examine the relationship between the rotational movement of the maxilla and the corresponding coordinate differences. Results Significant differences were observed in the transverse ( p  = 0.005), anteroposterior ( p  = 0.016), and vertical ( p  = 0.003) coordinates between the maxillary positions derived from CW and VMS. In MMS, the presence of roll movement significantly influenced transverse position ( p  = 0.002), pitch affected vertical position ( p  < 0.001), and yaw impacted transverse ( p  = 0.005) and vertical ( p  = 0.019) positions. Conclusion 3DW demonstrated greater accuracy than MMS with CW. Especially in cases involving rotational maxillary movements such as roll, yaw, and pitch, it resulted in fewer errors compared to MMS with CW. Consequently, 3DW offers more precise recording of maxillary repositioning plan and contributes to the successful transfer of this plan into the surgical outcome in orthognathic surgery.

Background To evaluate the nasolabial soft tissue change three-dimensionally after orthognathic surgery, using a structured light scanner. Methods Thirty-two malocclusion patients, who underwent orthognathic surgery, were evaluated. CBCT and 3D facial scans were obtained before surgery and 3 months after surgery. The 3D changes in the 26 landmarks, and the relative ratio of the soft tissue movement to the bony movement, were evaluated. Results In the Le Fort I advancement patients, the nasal tip moved 17% forward, compared to the maxillary bony movement, but the nasal prominence decreased 15%. The alar width increased 4 mm after the advancement, and the width decreased 4.7 mm after Le Fort I setback. The relative ratio of the soft tissue movement to the bony movement after bilateral sagittal split osteotomy was about 66% at the Li point in the anteroposterior direction, and it was 21% in the Le Fort I advancement and 14% in Le Fort I setback at the Ls point. Conclusion Alar cinch suturing may not be sufficient to overcome the effect of the maxilla advancement compressing the nasal complex. Alar width widening was prevented in Le Fort I setback. However, it is uncertain that the alar cinch suturing was solely responsible. The soft tissue around the mandible tends to accompany the bony movement more than the maxillary area. In addition, structured light scanning system proved to be a useful tool to evaluate the nasolabial soft tissue.

Background We investigated whether GKN1, a gastric tumor suppressor, contributes to the progression of gastric cancer by regulating RhoA expression. Methods We analyzed the expression of GKN1, RhoA, miR-185, and miR-34a in 35 gastric cancer tissues, and compared their expression with T category and TNM stage. Cell migration and invasion, as well as the expression of epithelial-to-mesenchymal transition (EMT)-related proteins, were assessed in GKN1 - and RhoA small interfering RNA (siRhoA)-transfected and recombinant-GKN1-treated AGS and MKN1 gastric cancer cells. Results Expression of RhoA protein and messenger RNA (mRNA) was increased in 15 (42.9 %) and 17 (48.6 %) of 35 gastric cancer tissues respectively, and was associated with higher T category and TNM stage. GKN1 expression was significantly decreased in 27 gastric cancers (77.1 %) with a higher T category, and was inversely correlated with RhoA mRNA expression. In AGS and MKN1 cells, GKN1 expression increased miR-185 and miR-34a expression and reduced RhoA mRNA and protein expression. A positive relationship between GKN1 and miR-34a and miR-185 expression and an inverse relationship between miR-34a and RhoA expression were observed in gastric cancer tissues. Cell migration and invasiveness were markedly decreased in GKN1 - and siRhoA-transfected cells. GKN1 expression and silencing of RhoA decreased the expression of the proteins Snail, Slug, and vimentin. Furthermore, miR-185 and miR-34a silencing in MKN1 cells transfected with GKN1 stimulated cell migration and invasion, and increased the expression of EMT-related proteins. Conclusion Our data suggest that GKN1 may inhibit gastric cancer cell migration and invasion by downregulating RhoA expression in a miR-185- and miR-34a-dependent manner.

Background This study aims to measure and compare the differences in vertical bone resorption after vertical augmentation using different types of autologous block bone. Methods Data were collected from 38 patients who had undergone vertical ridge augmentation using an autologous block bone before implant insertion. The patients were divided into three groups based on the donor sites: ramus bone (RB), chin bone (CB), and iliac crestal bone (IB). Results The surgical outcome of the augmentation was evaluated at the follow-up periods up to 60 months. In 38 patients, the mean amount of vertical bone gain was 8.36 ± 1.51 mm in the IB group, followed by the RB group (4.17 ± 1.31 mm) and the CB group (3.44 ± 1.08 mm). There is a significant difference in vertical bone resorption between the groups ( p  < 0.001), and the RB group demonstrated significantly lower resorption than the CB and IB groups ( p  = 0.011 and p  < 0.001, respectively). The most common postoperative complications included neurosensory disturbance in the CB graft and gait disturbance in the IB graft. Out of the 92 implants inserted after augmentation, four implants were lost during the study period, resulting in an implant success rate of 95.65%. Conclusions The RB graft might be the most suitable option for vertical augmentation in terms of maintaining postoperative vertical height and reducing morbidity, although the initial gain was greater with the IB graft compared to other block bones.

The aim of this study was to evaluate the effects of a partial glossectomy on volumetric changes of pharyngeal airway space (PAS) in patients with mandibular setback surgery. Overall, 25 patients showing clinical features related to macroglossia treated with mandibular setback surgery were included in this retrospective study. Subjects were divided into two groups: the control group (G1, n = 13, with BSSRO) and the study group (G2, n = 12, with both BSSRO and partial glossectomy). The PAS volume of both groups was measured by the OnDemand 3D program on CBCT taken shortly before operation (T0), 3 months post-operative (T1), and 6 months post-operative (T2). A paired t-test and repeated analysis of variance (ANOVA) were used for statistical correlation. Total PAS and hypopharyngeal airway space were increased after operation in Group 2 compared to Group 1 (p < 0.05), while oropharyngeal airway space showed no significant statistical difference with the tendency of increasing. The combination of partial glossectomy and BSSRO surgical techniques had a significant effect on increasing the hypopharyngeal and total airway space in class III malocclusion patients (p < 0.05).

Background As society becomes more complex, the incidence of mandibular fractures is increasing. This study aimed to analyze the incidence and type and identify etiological factors of mandibular fractures to use them in future treatments. Material and methods Data were collected from 224 patients who visited the department of oral and maxillofacial surgery at the Kyung Hee Medical Center dental hospital during a 6-year period (2016 to 2021). A logistic regression model was used for data analysis. Results In a total of 224 patients, 362 fractures were appeared. The average age of the patients was 34.1 years, with the highest incidence in the 20s. And the ratio between male and female was 4.09:1. Symphysis fractures were the most prevalent of all patients (52.7%), followed by unilateral condyle (37.1%), angle (36.2%), bilateral condyle (9.4%), body (8%), and coronoid (2.2%). The most common cause of fracture was daily-life activity (57.6%), followed by violence (30.4%), traffic accidents (8.5%), and syncope (3.6%). Patients with symphysis fracture were at low risk ( OR < 1) of angle, body, and unilateral condyle fractures. Similarly, patients with unilateral fracture were at low risk ( OR < 1) of symphysis, angle, body, and others site fractures. In contrast, patient with bilateral condyle fracture were at high risk ( OR > 1) of coronoid fractures. And younger patients were high risk of mandibular angle fractures. Conclusion Through this study, it was confirmed that etiological factors of mandibular fractures were like those of previous studies.

Background Foreign bodies may be embedded or left behind in the oral cavity during oral surgical procedure. The loss of instruments such as impression material, surgical gauze, and broken injection needles are commonly reported in the dental field. These complications are generally symptomatic and show signs of inflammation, pain, and purulent discharge. Accidental breakage of suture needles is a rare but potentially dangerous event. Case presentation In this report, we present one case of lost suture needle during the procedure of flap operation at local dental clinic and its successful removal under local/general anesthesia administration via CBCT with a help of two reference needles to localize the 6-0 nylon needle and consulting with the clinician. Conclusion CT scanning taken while mouth-closing may not be accurate with regard to real location measurement performed while mouth-opening. If so, other up-to-date radiographic devices and methods to retrieve a needle are recommended.

Purpose: This study aimed to propose a revision of the evaluation objectives of the Korean Dentist Clinical Skill Test by analyzing the opinions of those involved in the examination after a review of those objectives.Methods: The clinical skill test objectives were reviewed based on the national-level dental practitioner competencies, dental school educational competencies, and the third dental practitioner job analysis. Current and former examinees were surveyed about their perceptions of the evaluation objectives. The validity of 22 evaluation objectives and overlapping perceptions based on area of specialty were surveyed on a 5-point Likert scale by professors who participated in the clinical skill test and dental school faculty members. Additionally, focus group interviews were conducted with experts on the examination.Results: It was necessary to consider including competency assessments for “emergency rescue skills” and “planning and performing prosthetic treatment.” There were no significant differences between current and former examinees in their perceptions of the clinical skill test’s objectives. The professors who participated in the examination and dental school faculty members recognized that most of the objectives were valid. However, some responses stated that “oromaxillofacial cranial nerve examination,” “temporomandibular disorder palpation test,” and “space management for primary and mixed dentition” were unfeasible evaluation objectives and overlapped with dental specialty areas.Conclusion: When revising the Korean Dentist Clinical Skill Test’s objectives, it is advisable to consider incorporating competency assessments related to “emergency rescue skills” and “planning and performing prosthetic treatment.”

A sneak path current—a current passing through a neighboring memory cell—is an inherent and inevitable problem in a crossbar array consisting of memristor memory cells. This serious problem can be alleviated by serially connecting the selector device to each memristor cell. Among the various types of selector device concepts, the diffusive selector has garnered considerable attention because of its excellent performance. This selector features volatile threshold switching (TS) using the dynamics of active metals such as Ag or Cu, which act as an electrode or dopant in the solid electrolyte. In this study, a diffusive selector based on Ag-doped HfOx is fabricated using a co-sputtering system. As the Ag concentration in the HfOx layer varies, different electrical properties and thereby TS characteristics are observed. The necessity of the electroforming (EF) process for the TS characteristic is determined by the proper Ag concentration in the HfOx layer. This difference in the EF process can significantly affect the parameters of the TS characteristics. Therefore, an optimized doping condition is required for a diffusive selector to attain excellent selector device behavior and avoid an EF process that can eventually degrade device performance.

Mott threshold switching, which is observed in quantum materials featuring an electrically fired insulator-to-metal transition, calls for delicate control of the percolative dynamics of electrically switchable domains on a nanoscale. Here, we demonstrate that embedded metallic nanoparticles (NP) dramatically promote metastability of switchable metallic domains in single-crystal-like VO 2 Mott switches. Using a model system of Pt-NP-VO 2 single-crystal-like films, interestingly, the embedded Pt NPs provide 33.3 times longer ‘memory’ of previous threshold metallic conduction by serving as pre-formed ‘stepping-stones’ in the switchable VO 2 matrix by consecutive electical pulse measurement; persistent memory of previous firing during the application of sub-threshold pulses was achieved on a six orders of magnitude longer timescale than the single-pulse recovery time of the insulating resistance in Pt-NP-VO 2 Mott switches. This discovery offers a fundamental strategy to exploit the geometric evolution of switchable domains in electrically fired transition and potential applications for non-Boolean computing using quantum materials. Control of percolative dynamics of metal and insulator domains during electrically triggered insulator-metal transition underlies applications in energy-efficient switches. Jo et al. show that embedded metallic nanoparticles enhance the metastability and memory effects of metallic domains in VO 2 switches.