Exploration and clinical application of the "digital and intelligent surgery" diagnosis and treatment workflow for oral and maxillofacial tumors

The LaryngoscopeVolume 131, Issue 7 p. E2276-E2276 Head and Neck In Response to Assessing the Performance of the Shikani Optical Stylet for Awake Nasal Intubation Tong Cheng MD, Department of Anesthesiology, Peking University School and Hospital of Stomatology, Beijing, People's Republic of ChinaSearch for more papers by this authorLi-Kuan Wang MD, Corresponding Author wanglikuan3@163.com orcid.org/0000-0002-8019-2641 Department of Anesthesiology, Peking University School and Hospital of Stomatology, Beijing, People's Republic of China Send correspondence to Li-Kuan Wang, MD, Department of Anesthesiology, Peking University School and Hospital of Stomatology, #22 Zhongguancun South Avenue, Haidian District, Beijing 100081, People's Republic of China. E-mail: wanglikuan3@163.comSearch for more papers by this authorXu-Dong Yang MD, PhD, Department of Anesthesiology, Peking University School and Hospital of Stomatology, Beijing, People's Republic of ChinaSearch for more papers by this author Tong Cheng MD, Department of Anesthesiology, Peking University School and Hospital of Stomatology, Beijing, People's Republic of ChinaSearch for more papers by this authorLi-Kuan Wang MD, Corresponding Author wanglikuan3@163.com orcid.org/0000-0002-8019-2641 Department of Anesthesiology, Peking University School and Hospital of Stomatology, Beijing, People's Republic of China Send correspondence to Li-Kuan Wang, MD, Department of Anesthesiology, Peking University School and Hospital of Stomatology, #22 Zhongguancun South Avenue, Haidian District, Beijing 100081, People's Republic of China. E-mail: wanglikuan3@163.comSearch for more papers by this authorXu-Dong Yang MD, PhD, Department of Anesthesiology, Peking University School and Hospital of Stomatology, Beijing, People's Republic of ChinaSearch for more papers by this author First published: 13 April 2021 https://doi.org/10.1002/lary.29567 The authors have no funding, financial relationships, or conflicts of interest to disclose. Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume131, Issue7July 2021Pages E2276-E2276 RelatedInformation

Objective: To evaluate the pink and white esthetics of conventional and socket shield technique (SST) immediate implant restoration. Methods: Thirty volunteers were recruited according to preset criteria, and were assigned to 3 groups. Natural teeth group (ten undergraduates or postgraduates from Peking University School and Hospital of Stomatology in January 2020, n=10): all volunteers' maxillary anterior teeth were natural teeth with healthy gingiva, and none of the teeth were restored by crowns or composite. Conventional group and SST group (patients had a maxillary central incisor immediate implant placed in Department of Prosthodontics, Peking University School and Hospital of Stomatology during October 2016 to January 2021, n=10 for each group): the volunteer had an unrestored natural maxillary central incisor, and the contralateral maxillary central incisor was restored by conventional or SST immediate implant placement, temporization and all ceramic final restoration, photos were taken 12 months post-surgery. Three groups of evaluators namely layperson (staff from Second Clinical Division of Peking University School and Hospital of Stomatology and 2 family members, n=10), dental students (class 2015 undergraduates from Peking University School and Hospital of Stomatology, n=10) and prosthodontists (from Department of Prosthodontics, Peking University School and Hospital of Stomatology, n=10) were invited to assess the esthetics using pink esthetic score (PES) and white esthetic score (WES). The results were statistically analyzed. Results: PES and WES of natural teeth group [9(8, 10) and 8(7, 10)] were significantly higher than conventional group [7(6,8) and 7(6,9)] (H=287.08, 132.79,P<0.01) and SST group [7(6, 9) and 8(7, 9)] (H=216.01, 101.21, P<0.01). SST group yielded higher PES than the conventional group (H=-71.06, P<0.01), yet had similar WES (H=-31.57, P>0.05). Dental students had significant lower PES and WES than prosthodontists (H=-120.90, -218.86, P<0.01) and layperson (H=-109.55, 134.97, P<0.01). Prosthodontists and layperson got similar PES (H=-11.36, P>0.05), however yielded different WES (H=-83.89, P<0.01). Conclusions: SST immediate implant placement obtained better pink esthetics than conventional protocol 12-month after implant surgery, profession may have significant impact on evaluators during pink and white esthetic evaluation.

To investigate the clinical characteristics of oral and maxillofacial tumors in children and adolescents. This is a retrospective study of patients who had oral and maxillofacial tumors under the age of 18 years and were treated at the Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology from January 1990 to July 2021 (31y). Their general conditions, pathological diagnosis, gender, age, and anatomical location were counted to analyze their morbidity and composition characteristics. This study contained 5405 cases, including 2903 male patients and 2502 female patients, with a median age of 9 years. Peak incidence was observed in the 14 to 18 years age group. The mandible (22.15%), maxilla (11.75%), and tongue (9.25%) were the most common sites of incidence. Malignant and intermediate type tumors accounted for 13.04%, benign tumors and tumor-like lesions for 55.67%, most often occurs in the maxillofacial bone, of which fibro-osseous lesions constitute an important part. Cysts accounted for 31.29%. Among the tumors occurring in the jaws, the most common malignant type was sarcoma, and ameloblastoma was the most common benign tumor. Malignant jaw tumors were mostly treated by resection, 10.64% by fibular flap reconstruction. While benign jaw tumors and tumor-like lesions were mostly treated by resection or curettage. The distribution of anatomical location and pathological types of oral and maxillofacial tumors in children has certain characteristics, so that the selection of their treatment options is different from that of adults due to the consideration of the growth and developmental characteristics of children.

ObjectiveTo evaluate the feasibility and effectiveness of mixed reality combined with surgical navigation for resection of oral and maxillofacial tumors.MethodsPatients with maxillary or mandibular tumors in the oral and maxillofacial region who underwent surgical treatment at Peking University School and Hospital of Stomatology between January 2020 and June 2023 were enrolled in this study. During the preoperative phase, patients in the mixed reality–surgical navigation group (MRSN group) underwent additional image data processing using mixed reality–surgical navigation technology, which enabled intraoperative tumor localization and resection under navigation guidance. The control group underwent conventional virtual surgical planning (VSP) incorporating computer-aided design (CAD) and computer-aided manufacturing (CAM). Tumor resection in the control group was also performed under surgical navigation guidance. Baseline patient characteristics were recorded for both groups. Using a normal vector–based selection method, osteotomy planes were extracted from the preoperative virtual surgical plan and from postoperative computed tomography reconstruction models using digital software for chromatographic analysis. Deviations between planned and actual osteotomy planes were compared between the two groups. All analyses were performed using SPSS 26.0 software (IBM Corp, Armonk, NY, USA), with statistical significance set at P < 0.05.ResultsA total of 38 patients were included, with 19 patients in each group. The mean osteotomy deviation was significantly smaller in the MRSN group than in the control group (1.84 mm vs. 3.07 mm, P < 0.001). Chromatographic analysis showed that 74.84% of osteotomy points in the MRSN group deviated by less than 3 mm, compared with 64.81% in the control group. Subgroup analyses by tumor location (maxillary vs. mandibular) and pathology (benign vs. malignant) demonstrated consistently smaller deviations in the MRSN group. No significant differences in osteotomy accuracy were observed between maxillary and mandibular tumors or between benign and malignant tumors within either group (P > 0.05). During a mean follow-up of 27 months in the MRSN group, five patients experienced complications, including facial paralysis, skin numbness, and titanium mesh exposure; no tumor recurrence or distant metastasis was observed. In the control group, with a mean follow-up of 18.8 months, two patients developed complications (infection and titanium mesh exposure), and three patients experienced tumor recurrence.ConclusionThe clinical application of mixed reality combined with surgical navigation is feasible for the resection of oral and maxillofacial tumors. Compared with conventional navigation systems, this approach allows more precise localization of osteotomy planes and improves the accuracy of tumor resection.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12903-026-07871-0.

3D Printing Individual Templates Guided Brachytherapy in Head and Neck

Objective: To investigate the disease types, clinical characteristics, and emergency manage ment measures for critical cases in the oral emergency department, and to provide a reference for improving the basic emergency rescue capabilities of dental practitiers. Methods: A retrospellive analysis was conducted on patients with complete medical records who were admitted to the Department of Oral Emergency, Peking University School and Hospital of Stomatology from January 2006 to September 2025. Basic information and rescue data of the patients were collected, and the disease composition, key characteristics of clinical treatment and disease outcome were studied and analyzed. Results: A total of 92 patients were included, with an average age of 47 years (4 to 88 years, median 49 years). There were 62 male patients (67.4%) and 30 female patients (32.6%). Among the critically ill patients who visited the oral emergency department in the past 20 years, 61.9% were diagnosed with maxillofacial hemorrhage and cardiovascular accidents, accounting for 38.0% (35/92) and 23.9% (22/92) of the rescued patients, respectively, which were the most common diagnoses in emergency rescue. The next most common were upper airway obstruction in 17 cases and vasovagal syncope in 13 cases, accounting for 32.6% of the rescued patients. Among the 35 cases of maxillofacial hemorrhage, 20 patients (57.1%) had maxillofacial trauma, and 17 patients (48.6%) developed hemorrhagic shock. The study observed that secondary hemorrhage and airway obstruction caused by maxillofacial tumors were common causes of oral critical rescue, accounting for 34.3% (12/35) and 12/17 of the hemorrhage and airway obstruction cases, respectively. The study observed that 5 patients with airway obstruction caused by space infection received emergency treatment, accounting for 29.4% (5/17) of the airway obstruction patients. In the rescue work of oral emergencies, electrocardiogram monitoring (98.9%, 91/92), oxygen inhalation (96.7%, 89/92), and opening of venous access (78.3%, 72/92) were the most commonly used supportive treatment techniques; tracheal intubation was the main measure for respiratory system emergency rescue, followed by cricothyrotomy and tracheotomy. All 15 patients with cardiac arrest received cardiopulmonary resuscitation treatment, and 8 patients underwent defibrillation. Adrenaline was the most frequently used drug in emergency rescue, mainly applied to patients with cardiac arrest and anaphylactic shock, followed by nitroglycerin, lidocaine, dopamine, aspirin, and midazolam. The rescue success rate of the 92 cases receiving emergency treatment was 91.3% (84/92), and 8 deaths included 3 cases of cardiac arrest caused by airway obstruction and 5 cases of respiratory and circulatory failure. Conclusions: Dental practitioners should be able to quickly identify medical emergencies and immediately carry out emergency rescue. Oral departments should be equipped with relevant emergency drugs and equipment, and medical staff should receive regular emergency skills training to improve their ability to handle medical emergencies and enhance medical safety.

To evaluate the design and manufacture accuracy of a domestic computer aided design (CAD) and computer aided manufacture (CAM) system, and to compare it with similar foreign products. Thirty models of posterior-teeth-single-crown preparations were collected, and STL data of these preparations was collected by Denmark 3Shape scanner. Three copings were made for each preparation, the one designed and manufactured using commercial CAD/CAM system (3Shape CAD software and Wieland T1 CAM equipment) was assigned into control group T0, the one designed and manufactured using domestic CAD software (developed by Peking University School and Hospital of Stomatology and Nanjing University of Aeronautics and Astronautics) and Wieland T1 CAM equipment was assigned into experimental group TCAD for design accuracy evaluation, and the one designed and manufactured using 3Shape CAD software and domestic CAM equipment (developed by Peking University School and Hospital of Stomatology, Tsinghua University and ShanDong XinHua Incorporated Company of medical apparatus and instruments) was assigned into experimental group TCAM for manufacture accuracy evaluation. Finally, the marginal fitness were compared and evaluated by using 3D & Profile measurement microscope laser. The marginal fitness of TCAD was 27.98 (19.10, 46.57) µm in buccal, 32.67 (20.65, 50.82) µm in lingual, 27.38 (22.53, 52.61) µm in mesial, 29.50 (22.68, 53.65) µm in distal; of TCAM was 21.69 (15.87, 30.21) µm in buccal, 18.51 (13.50, 22.51) µm in lingual, 19.15 (15.42, 26.89) µm in mesial, 22.77 (18.58, 32.15) µm in distal; and there were no statistical differences compared with T0 [20.16 (17.16, 48.00) µm in buccal, 21.51 (17.05, 28.31) µm in lingual, 23.54 (17.89, 30.04) µm in mesial and 23.94 (17.93, 28.19) µm in distal] except lingual data of TCAD. The design and machining precision of this domestic CAD/CAM system is at the same level of those comparable foreign products.

Objective: To explore the establishment of an efficient and automatic method to determine anatomical landmarks in three-dimensional (3D) facial data, and to evaluate the effectiveness of this method in determining landmarks. Methods: A total of 30 male patients with tooth defect or dentition defect (with good facial symmetry) who visited the Department of Prosthodontics, Peking University School and Hospital of Stomatology from June to August 2021 were selected, and these participants' age was between 18-45 years. 3D facial data of patients was collected and the size normalization and overlap alignment were performed based on the Procrustes analysis algorithm. A 3D face average model was built in Geomagic Studio 2013 software, and a 3D face template was built through parametric processing. MeshLab 2020 software was used to determine the serial number information of 32 facial anatomical landmarks (10 midline landmarks and 22 bilateral landmarks). Five male patients with no mandibular deviation and 5 with mild mandibular deviation were selected from the Department of Orthodontics or Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology from June to August 2021. 3D facial data of patients was collected as test data. Based on the 3D face template and the serial number information of the facial anatomical landmarks, the coordinates of 32 facial anatomical landmarks on the test data were automatically determined with the help of the MeshMonk non-rigid registration algorithm program, as the data for the template method to determine the landmarks. The positions of 32 facial anatomical landmarks on the test data were manually determined by the same attending physician, and the coordinates of the landmarks were recorded as the data for determining landmarks by the expert method. Calculated the distance value of the coordinates of facial anatomical landmarks between the template method and the expert method, as the landmark localization error, and evaluated the effect of the template method in determining the landmarks. Results: For 5 patients with no mandibular deviation, the landmark localization error of all facial anatomical landmarks by template method was (1.65±1.19) mm, the landmark localization error of the midline facial anatomical landmarks was (1.19±0.45) mm, the landmark localization error of bilateral facial anatomical landmarks was (1.85±1.33) mm. For 5 patients with mild mandibular deviation, the landmark localization error of all facial anatomical landmarks by template method was (2.55±2.22) mm, the landmark localization error of the midline facial anatomical landmarks was (1.85±1.13) mm, the landmark localization error of bilateral facial anatomical landmarks was (2.87±2.45) mm. Conclusions: The automatic determination method of facial anatomical landmarks proposed in this study has certain feasibility, and the determination effect of midline facial anatomical landmarks is better than that of bilateral facial anatomical landmarks. The effect of determining facial anatomical landmarks in patients without mandibular deviation is better than that in patients with mild mandibular deviation.

Objective: To explore a three-dimensional point cloud completion method based on an octree diffusion model for intelligent generation of personalized dental crown occlusal morphology, and to evaluate the similarity and functional adaptability of the generated crown occlusal surfaces compared with natural teeth. Methods: A total of 780 intraoral scan datasets of unilateral maxillary and mandibular second premolars to second molars were selected from the DCPR-GAN database (https://github.com/Sukhum169/DCPR-GAN). The data were obtained from Peking University School and Hospital of Stomatology and Nanjing Stomatological Hospital, involving patients aged 35-50 years. Among them, 720 cases were used for model training and 60 for testing. An octree-structured diffusion model was constructed to achieve two stages of three-dimensional crown morphology generation: unconditional generation and mask-conditioned generation. In the unconditional generation stage, Earth mover's distance (EMD) was used as the metric for morphological discrepancy, and the occlusal contact areas of generated crowns (DM-U) were compared with those of natural teeth. Statistical analysis was performed using the Kruskal-Wallis test. In the conditional generation stage, clinical intraoral scan data were collected from 12 healthy volunteers at Peking University School and Hospital of Stomatology between September 2024 and February 2026, including six males and six females aged 22-24 years. Crowns were generated for the diffusion model generated crown with the mask condition group (DM group) and compared among four groups: natural teeth (NA group), technician-designed crowns (TE group), and automatically generated crowns (AT group). Three-dimensional coordinate deviations and euclidean distance errors of five anatomical landmarks were analyzed. Root mean square error (RMSE) of the three-dimensional surface was calculated using natural teeth as the gold standard. Statistical analysis was performed using the Friedman test. Results: In the unconditional generation evaluation, EMD results showed a coverage rate of 50.88%, a minimum matching distance (MMD) of 1.74, and a 1-nearest neighbor accuracy (1-NNA) of 0.504, indicating high similarity between generated crowns and natural teeth in feature space. Comparison of occlusal contact area showed no statistically significant difference between the DM and NA groups (χ²=0.75, P=0.387). In the conditional generation evaluation, the RMSE values for the TE, AT, and DM groups were 0.39 (0.11), 0.37 (0.13), and 0.31 (0.10) mm, respectively, with no significant overall difference among the three groups (χ²=3.50, P=0.174). Conclusions: The three-dimensional point cloud completion method based on an octree diffusion model can effectively learn the occlusal morphology of natural crowns and achieve personalized reconstruction of crown occlusal surfaces. The generated crown occlusal morphology demonstrated similarity to natural teeth and functional adaptability comparable to technician-designed methods.

Objective: To evaluate the correlation between peri-implant probing depth (PPD) and radiographic bone level (rBL) in implants with peri-implantitis. Methods: From January 2019 to December 2022, 24 patients with 30 implants who suffered from peri-implantitis at the Department of Periodontology, Peking University School and Hospital of Stomatology were included in the present research. SPSS 26.0 software was used to simple random sampling select 30 healthy implants from which with electronic examination records in Department of Periodontology, Peking University School and Hospital of Stomatology from January 2007 to June 2023 as the control group. On the premise of retaining the implant prosthesis, PPD (distance between pocket bottom and peri-implant soft tissue margin) was examined using a Williams periodontal probe with a light force (about 0.2 N), and a total of 4 sites were recorded for each implant. Periapical radiography and cone beam CT were applied to measure the rBL (distance between the reference point at the neck of the implant and the apical point of the bone defect) and the width of the bone defect (DW), and the type of the bone defect was recorded. The correlation and consistency between the diagnosis of PPD and rBL were analyzed. Results: PPD was significantly correlated with rBL in a total of 60 implants in 180 sites (r=0.64, P<0.001). The chi-square test showed an 8.15-fold increase in the detection rate of PD≥6 mm at sites with rBL≥1 mm (P<0.001). Multivariate logistic regression analysis showed that rBL was still statistically associated with PPD after adjustment for jaw position and examination position of implants. Take rBL <1 mm as reference, the odds ratios (OR) of 1 mm≤rBL<2 mm, 2 mm≤rBL<3 mm and rBL≥3 mm group with PPD were 6.23 (P=0.014), 2.77 (P=0.183) and 10.87 (P=0.001), respectively. Conclusions: There is a positive correlation between PPD and rBL in implants with peri-implantitis. PPD can be used as a clinical examination index to assist in estimating the level of peri-implant bone under the premise of retaining the prosthesis.

Sialoendoscopy-Assisted Sialolithectomy for Submandibular Hilar Calculi

Objective: To measure the crown conical degree of the remaining maxillary incisors in patients with congenital tooth agenesis, and to analyze the influence of different gene mutations on the crown conical degree of patients. Methods: Whole exome sequencing was performed on 85 patients with congenital tooth agenesis (50 males, 35 females, median age 19 years old) who visited the Department of Prosthodontics, Peking University School and Hospital of Stomatology from January 2019 to January 2023. The pathogenic gene was identified. The width of the crowns of the maxillary central and lateral incisors at the incisal 1/3 and gingival 1/3 were measured on the panoramic radiograph, and the ratio was defined as the crown conical degree. The smaller the ratio is, the more likely is the crown to be peg shaped teeth. The control group was matched by age and gender with 85 other patients with intact maxillary permanent incisors who were treated in the Department of Prosthodontics, Peking University School and Hospital of Stomatology from January 2019 to January 2023. The conical degree of the tooth agenesis group was compared with the control group by t-test, and the differences in the crown conical degree in different gene mutation groups were compared using one-way analysis of variance, and the multiple comparisons among gene groups were carried out using the LSD method. Results: Among the 85 tooth agenesis patients, the numbers of patients in each gene mutation group were 20 in ectodysplasin A (EDA) group, 8 in ectodysplasin A receptor (EDAR) group, 15 in wingless-type MMTV integration site family, member 10A (WNT10A) group, 16 in paired box 9 (PAX9) group, 10 in Msh homeobox 1 (MSX1) group, 10 in low-density Lipoprotein receptor related protein 6 (LRP6) group, and 6 in bone morphogenetic protein4 (BMP4) group. The number of missing teeth were 1-27, median number 15 among the tooth agenesis patients. There was no significant difference in the conical degree between the left and right homonymous teeth in the congenital tooth agenesis group and the control group (P>0.05). The crown conical degree of maxillary central incisor and lateral incisor in the congenital missing teeth group (0.95±0.24, 0.90±0.22) was significantly smaller than that in the control group (1.12±0.09, 1.13±0.09) (t=-8.50, P<0.001; t=-11.47, P<0.001). In WNT10A mutants, the conical degree of lateral incisors (0.89±0.18) was less than that of central incisors (1.07±0.15)(t=3.68, P<0.001). The conical degree of central incisors and lateral incisors (0.70±0.23, 0.57±0.15) of EDA mutants was significantly lower than that in patients with other gene mutations (P>0.05). Conclusions: Compared with the normal control group, the remaining maxillary central and lateral incisors of the seven gene mutation groups of patients with congenital tooth agenesis all had different degrees of conical crown. Among them, the crown conical degree of maxillary central and lateral incisors of the EDA mutation was the most severe, and the WNT10A mutation affected the maxillary lateral incisors more specifically.

This study aims to explore the transformative impact of Mixed Reality (MR) technologies in the U.S. retail sector. It focuses on analyzing how MR reshapes shopping experiences, enhances customer engagement, and influences the economic landscape of retail. The methodology encompasses a comprehensive literature review, utilizing academic journals, conference proceedings, and industry reports. The search strategy involved keyword searches and manual screening, with inclusion and exclusion criteria set to filter relevant literature. The selection criteria prioritized recent studies to capture the latest trends in MR technology. The key findings reveal that MR technologies have evolved significantly, offering immersive and interactive shopping experiences that revolutionize customer engagement and satisfaction. The economic implications of MR in retail are profound, indicating substantial market growth and financial opportunities for retailers. However, the adoption of MR also presents challenges, including the need for integration into existing retail models and the development of user-friendly interfaces. The study also highlights the importance of regulatory frameworks and standardization in the successful implementation of MR technologies in retail. In conclusion, MR technologies hold great potential for the retail sector, offering innovative ways to engage customers and enhance their shopping experiences. However, realizing these opportunities requires overcoming various challenges, including adapting financial strategies and addressing infrastructure needs. As MR continues to evolve, it is poised to play a pivotal role in shaping the future of the retail sector. The study underscores the need for ongoing research to fully understand and leverage the potential of MR in retail.

Objective: To conduct economic evaluation of treatments under dental general anesthesia (DGA) and protective stabilization (PS), in order to compare the cost and the final therapeutic effect of these two treatments. Methods: Retrospectively studied twenty-six 2 to 4 years old patients treated under DGA and twenty-seven treated under PS in the Department of Pediatric Dentistry, Peking University School and Hospital of Stomatology. The general information, treatment information and total treatment cost information of patients were collected. The cost and cost-survival time ratio of the two groups were compared in units of people and tooth respectively. When compared in unit of people, patients were divided into two groups depending on the number of teeth treated, when compared in unit of tooth, teeth were divided into two groups depending on the treatment received, i.e. restoration or root canal treatment. In addition, we recalculated and compared two groups under the assumption that the treatment charges of DGA was consistent with common outpatient charges. Results: The tooth average cost and cost-survival time ratio of each patient in DGA group which were [(1 133.87±87.37) yuan] and [3.51 (1.30, 5.72) yuan/d] respectively were significantly higher than those in PS group which were [(303.81±155.34) yuan] and [1.54 (0.95, 2.13) yuan/d] respectively (P<0.01). The number of teeth and the way of treatments wouldn't change the result. The recalculated result of the cost-survival time ratio of each patient in DGA group [1.63 (0.72, 2.55) yuan/d] and PS group [1.54 (0.95, 2.13) yuan/d] showed no significant difference (P=0.455). Conclusions: Patients treated in Peking University School and Hospital of Stomatology showed a significant higher cost and cost-survival time radio in DGA group than that in PS group. If the treatment charges of DGA group was consistent with common outpatient charges, PS group will no longer have economic advantage.

Objectives: Mixed reality (MR) technology has emerged in recent years and allows three-dimensional visualization, multiangle observation, remote vision, and virtual-real interaction. This study aims to explore the influence of MR technology on the outcomes and strategy planning of robotic surgery for complex renal tumors. Patients and Methods: A total of 92 patients with complex renal tumors were enrolled in this study from June 2018 to June 2020. All patients were found to have tumors by magnetic resonance imaging (MRI) in our department. This trial follows CONSORT guidelines and adopts a single-blind parallel design and randomizes patients with a random number table. The study was approved by the institutional review board, and written informed consent was obtained from each participant. All surgeries were performed by three experienced and high-volume surgeons. The demographic indicators, intraoperative and postoperative complications, renal function outcomes, pathological results, and surgical strategies were recorded. Student's t-test and Wilcoxon rank-sum test were used to compare continuous variables, and Pearson's chi-squared and Fisher's exact tests were used to compare categorical variables. Results: Warm ischemia time (WIT) mainly comprises tumor resection time and reconstruction time, and the reconstruction time accounts for a larger proportion. For urologists treating complex renal tumors, MR technology can help them reduce the warm ischemia time (21.3 ± 4.0 vs 23.6 ± 5.9 minutes, p = 0.031), reconstruction time (15.4 ± 3.8 vs 17.2 ± 4.2 minutes, p = 0.034), estimated blood loss (p = 0.044), operation time (125.7 ± 26.3 vs 144.6 ± 27.9 minutes, p = 0.001), and intraoperative complications (p = 0.030). Conclusions: MR-assisted surgery can reduce the incidence of intraoperative complications and improve perioperative outcomes, and MR may be a good preoperative tool for planning complex renal tumor surgery.