Preliminary evaluation of the trueness of 5 chairside 3D facial scanning techniques / 北京大学学报(医学版)

OBJECTIVE@#To quantitatively evaluate the trueness of five chairside three-dimensional facial scanning techniques, and to provide reference for the application of oral clinical diagnosis and treatment.@*METHODS@#The three-dimensional facial data of the subjects were collected by the traditional professional three-dimensional facial scanner Face Scan, which was used as the reference data of this study. Four kinds of portable three-dimensional facial scanners (including Space Spider, LEO, EVA and DS-FScan) and iPhone Ⅹ mobile phone (Bellus3D facial scanning APP) were used to collect three-dimensional facial data from the subjects. In Geomagic Studio 2013 software, through data registration, deviation analysis and other functions, the overall three-dimensional deviation and facial partition three-dimensional deviation of the above five chairside three-dimensional facial scanning technologies were calculated, and their trueness performance evaluated. Scanning time was recorded during the scanning process, and the subject's comfort was scored by visual analogue scale(VAS). The scanning efficiency and patient acceptance of the five three-dimensional facial scanning techniques were evaluated.@*RESULTS@#DS-FScan had the smallest mean overall and mean partition three-dimensional deviation between the test data and the reference data, which were 0.334 mm and 0.329 mm, respectively. The iPhone Ⅹ mobile phone had the largest mean overall and mean partition three-dimensional deviation between the test data and the reference data, which were 0.483 mm and 0.497 mm, respectively. The detailed features of the three-dimensional facial data obtained by Space Spider were the best. The iPhone Ⅹ mobile phone had the highest scanning efficiency and the highest acceptance by the subject. The average scanning time of the iPhone Ⅹ mobile phone was 14 s, and the VAS score of the subjects' scanning comfort was 9 points.@*CONCLUSION@#Among the five chairside three-dimensional face scanning technologies, the trueness of the scan data of the four portable devices had no significant difference, and they were all better than the iPhone Ⅹ mobile phone scan. The subject with the iPhone Ⅹ scanning technology had the best expe-rience.

Study on the method of automatically determining maxillary complex landmarks based on non-rigid registration algorithms / 中华口腔医学杂志

Objective: To explore an automatic landmarking method for anatomical landmarks in the three-dimensional (3D) data of the maxillary complex and preliminarily evaluate its reproducibility and accuracy. Methods: From June 2021 to December 2022, spiral CT data of 31 patients with relatively normal craniofacial morphology were selected from those who visited the Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology. The sample included 15 males and 16 females, with the age of (33.3±8.3) years. The maxillary complex was reconstructed in 3D using Mimics software, and the resulting 3D data of the maxillary complex was mesh-refined using Geomagic software. Two attending physicians and one associate chief physician manually landmarked the 31 maxillary complex datasets, determining 24 anatomical landmarks. The average values of the three expert landmarking results were used as the expert-defined landmarks. One case that conformed to the average 3D morphological characteristics of healthy individuals' craniofacial bones was selected as the template data, while the remaining 30 cases were used as target data. The open-source MeshMonk program (a non-rigid registration algorithm) was used to perform an initial alignment of the template and target data based on 4 landmarks (nasion, left and right zygomatic arch prominence, and anterior nasal spine). The template data was then deformed to the shape of the target data using a non-rigid registration algorithm, resulting in the deformed template data. Based on the unchanged index property of homonymous landmarks before and after deformation of the template data, the coordinates of each landmark in the deformed template data were automatically retrieved as the automatic landmarking coordinates of the homonymous landmarks in the target data, thus completing the automatic landmarking process. The automatic landmarking process for the 30 target data was repeated three times. The root-mean-square distance (RMSD) of the dense corresponding point pairs (approximately 25 000 pairs) between the deformed template data and the target data was calculated as the deformation error of the non-rigid registration algorithm, and the intra-class correlation coefficient (ICC) of the deformation error in the three repetitions was analyzed. The linear distances between the automatic landmarking results and the expert-defined landmarks for the 24 anatomical landmarks were calculated as the automatic landmarking errors, and the ICC values of the 3D coordinates in the three automatic landmarking repetitions were analyzed. Results: The average three-dimensional deviation (RMSD) between the deformed template data and the corresponding target data for the 30 cases was (0.70±0.09) mm, with an ICC value of 1.00 for the deformation error in the three repetitions of the non-rigid registration algorithm. The average automatic landmarking error for the 24 anatomical landmarks was (1.86±0.30) mm, with the smallest error at the anterior nasal spine (0.65±0.24) mm and the largest error at the left oribital (3.27±2.28) mm. The ICC values for the 3D coordinates in the three automatic landmarking repetitions were all 1.00. Conclusions: This study established an automatic landmarking method for three-dimensional data of the maxillary complex based on a non-rigid registration algorithm. The accuracy and repeatability of this method for landmarking normal maxillary complex 3D data were relatively good.

Advances in algorithms for three-dimensional craniomaxillofacial features construction based on point clouds / 中华口腔医学杂志

In light of the increasing digitalization of dentistry, the automatic determination of three-dimensional (3D) craniomaxillofacial features has become a development trend. 3D craniomaxillofacial landmarks and symmetry reference plane determination algorithm based on point clouds has attracted a lot of attention, for point clouds are the basis for virtual surgery design and facial asymmetry analysis, which play a key role in craniomaxillofacial surgery and orthodontic treatment design. Based on the studies of our team and national and international literatures, this article presented the deep geometry learning algorithm to determine landmarks and symmetry reference plane based on 3D craniomaxillofacial point clouds. In order to provide reference for future clinical application, we describe the development and latest research in this field, and analyze and discuss the advantages and limitations of various methods.

The design method of the digital sequential tooth-sectioning guide for the extraction of mandibular impacted third molars / 中华口腔医学杂志

Objective: To explore a method for digitally designing and fabricating a sequential tooth-sectioning guide that can assist in the extraction of mandibular horizontal impacted third molars, preliminarily evaluate its feasibility and provide a reference for clinical application. Methods: Twenty patients with mandibular low level impacted third molars who visited the Department of General Dentistry, Peking University School and Hospital of Stomatology from March 2021 to January 2022 were selected. Cone-beam CT showed direct contact between the roots and mandibular canal, and full range impressions of the patients' intraoral teeth were taken and optical scans of the dental model were performed. The patients' cone-beam CT data and optical scan data were reconstructed in three dimensions, anatomical structure extraction, registration fusion, and the design of the structure of the guide (including crown-sectioning guide and root-sectioning guide) by Mimics 24.0, Geomagic Wrap 2021, and Magics 21.0 software, and then the titanium guide was three dimension printed, and the guide was tried on the dental model. After confirmation, the guide was used to assist the dentist in the operation. We observed whether the guide was in place, the number of tooth splitting, the matching of tooth splitting with the preoperative design, the operation time, and whether there were any complications. Results: In this study, 20 sectioning guides were successfully printed, all of them were well fitted in the patients' mouth, the average number of section was 3.4 times, the tooth parts was better matched with the preoperative design, and the average operative time of the guides was (29.2±9.8) minutes without complications such as perforation of the bone cortex. Conclusions: The use of sequential sectioning guides to assist in the extraction of mandibular impacted third molars was initially validated to accurately replicate the preoperative sectioning design, and is expected to provide a digital solution to improve surgical precision and ensure safety. Further studies with larger sample sizes are needed to evaluate its accuracy and safety.

Preliminary study on three-dimensional morphological reconstruction method for external nose defect based on three-dimensional face template / 中华口腔医学杂志

Objective: To provide a new solution for the digital design of nasal prostheses, this study explores the three-dimensional (3D) facial morphology completion method for external nasal defects based on the non-rigid registration process of 3D face template. Methods: A total of 20 male patients with tooth defect and dentition defect who visited the Department of Prosthodontics, Peking University School and Hospital of Stomatology from June to December 2022 were selected, age 18-45 years old. The original 3D facial data of patients were collected, and the 3D facial data of the external nose defect was constructed in Geomagic Wrap 2021 software. Using the structured 3D face template data constructed in the previous research of the research group, the 3D face template was deformed and registered to the 3D facial data of external nose defect (based on the morphology of non-defective area) by non-rigid registration algorithm (MeshMonk program), and the personalized deformed data of the 3D face template was obtained, as the complemented facial 3D data. Based on the defect boundary of the 3D facial data of the external nose defect, the complemented external nose 3D data can be cut out from the complemented facial 3D data. Then the nasofacial angle and nasolabial angle of the complemented facial 3D data and the original 3D facial data was compared and analyzed, the ratio between the nose length and mid-face height, nose width and medial canthal distance of the complemented facial 3D data was measured, the edge fit between the edge curve of the complemented external nose 3D data and the defect edge curve of the 3D facial data of external nose defect was evaluated, and the morphological difference of the nose between the complemented external nose 3D data and the original 3D facial data was analyzed. Results: There was no significant statistically difference (t=-0.23, P=0.823; Z=-1.72, P=0.086) in the nasofacial angle (28.2°±2.9°, 28.4°±3.5° respectively) and nasolabial angle [95.4°(19.2°), 99.9°(9.5°) respectively] between the 20 original 3D facial data and the complemented facial 3D data. The value of the ratio of nose length to mid-face height in the complemented facial 3D data was 0.63±0.03, and the value of the ratio of nose width to medial canthal distance was 1.07±0.08. The curve deviation (root mean square value) between the edge curve of the complemented external nose 3D data and the defect edge curve of the 3D facial data of external nose defect was (0.37±0.09) mm, the maximum deviation was (1.14±0.32) mm, and the proportion of the curve deviation value within±1 mm was (97±3)%. The distance of corresponding nose landmarks between the complemented facial 3D data and the original 3D facial data were respectively, Nasion: [1.52(1.92)] mm; Pronasale: (3.27±1.21) mm; Subnasale: (1.99±1.09) mm; Right Alare: (2.64±1.34) mm; Left Alare: (2.42± 1.38) mm. Conclusions: The method of 3D facial morphology completion of external nose defect proposed in this study has good feasibility. The constructed complemented external nose 3D data has good facial coordination and edge fit, and the morphology is close to the nose morphology of the original 3D facial data.

Decreased Expression of Urethral Caveolin-1, -2, and -3 in the Rat Model of Overactive Bladder: Potential Mediator of Functional Interaction of Urethra and Urinary Bladder / 대한배뇨장애요실금학회지

Purpose@#To investigate the effect of detrusor overactivity (DO) on the urethral expression of caveolin (CAV)-1, -2, and -3 of urethra in an animal model of cyclophosphamide (CYP)-induced cystitis rat. @*Methods@#Female Sprague-Dawley rats were divided into the control group (n=20) and the cystitis group (n=20). Cystitis was induced by intraperitoneal injection of CYP (200 mg/kg). An urodynamic study was done 3 days after the CYP injection to measure functional change of the urinary bladder and urethra. Cellular localization and expression of CAV-1, -2, and -3 in the rat urethra were determined by immunohistochemistry (IHC) and Western blot. @*Results@#Urodynamic experiments demonstrated a decreased contraction interval in the cystitis group compared to the control (3.9±1.0 minutes vs. 6.6±1.2 minutes, P<0.05). Conversely, contraction pressure increased significantly in the cystitis group compared to the control (22.4±0.7 mmHg vs. 11.5±0.4 mmHg, P<0.05). The urethral pressure was decreased in the cystitis group compared to the control (4.05 ±2.5 mmHg vs. 5.8 ±2.8 mmHg, P <0.05). The IHC and Western blot data showed that CAV-1, -2, and -3 expression decreased significantly in the cystitis group compared control group (P<0.05). @*Conclusions@#The decreased urethral CAV-1, -2, and -3 in the DO rats suggests that CAVs might be related with the functional change of urethra in association with DO of urinay bladder.

Automatic determination of mandibular landmarks based on three-dimensional mandibular average model / 北京大学学报(医学版)

OBJECTIVE@#To explore an efficient and automatic method for determining the anatomical landmarks of three-dimensional(3D) mandibular data, and to preliminarily evaluate the performance of the method.@*METHODS@#The CT data of 40 patients with normal craniofacial morphology were collected (among them, 30 cases were used to establish the 3D mandibular average model, and 10 cases were used as test datasets to validate the performance of this method in determining the mandibular landmarks), and the 3D mandibular data were reconstructed in Mimics software. Among the 40 cases of mandibular data after the 3D reconstruction, 30 cases that were more similar to the mean value of Chinese mandibular features were selected, and the size of the mandibular data of 30 cases was normalized based on the Procrustes analysis algorithm in MATLAB software. Then, in the Geomagic Wrap software, the 3D mandibular average shape model of the above 30 mandibular data was constructed. Through symmetry processing, curvature sampling, index marking and other processing procedures, a 3D mandible structured template with 18 996 semi-landmarks and 19 indexed mandibular anatomical landmarks were constructed. The open source non-rigid registration algorithm program Meshmonk was used to match the 3D mandible template constructed above with the tested patient's 3D mandible data through non-rigid deformation, and 19 anatomical landmark positions of the patient's 3D mandible data were obtained. The accuracy of the research method was evaluated by comparing the distance error of the landmarks manually marked by stomatological experts with the landmarks marked by the method of this research.@*RESULTS@#The method of this study was applied to the data of 10 patients with normal mandibular morphology. The average distance error of 19 landmarks was 1.42 mm, of which the minimum errors were the apex of the coracoid process [right: (1.01±0.44) mm; left: (0.56±0.14) mm] and maximum errors were the anterior edge of the lowest point of anterior ramus [right: (2.52±0.95) mm; left: (2.57±1.10) mm], the average distance error of the midline landmarks was (1.15±0.60) mm, and the average distance error of the bilateral landmarks was (1.51±0.67) mm.@*CONCLUSION@#The automatic determination method of 3D mandibular anatomical landmarks based on 3D mandibular average shape model and non-rigid registration algorithm established in this study can effectively improve the efficiency of automatic labeling of 3D mandibular data features. The automatic determination of anatomical landmarks can basically meet the needs of oral clinical applications, and the labeling effect of deformed mandible data needs to be further tested.

Preliminary study on the method of automatically determining facial landmarks based on three-dimensional face template / 中华口腔医学杂志

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.

Design of non-metallic crown for primary molars and analyzation of stress distribution: a finite element study / 中华口腔医学杂志

Objectives: To study the design of nonmetallic crowns for deciduous molars by means of computer aided design and to analyze the key parameters of the nonmetallic crowns of deciduous molars using finite element method. Methods: The three-dimensional model of a mandibular second primary molar was constructed by using a micro-CT system. The thickness of the crown was limited to 0.5 mm and four different crown shapes (chamfer+anatomic, chamfer+non-anatomic, knife edge+anatomic and knife edge+non-anatomic) were designed. Then, the crown shape was limited as chamfer+non-anatomic and five different thicknesses of the crown (0.50, 0.75, 1.00, 1.25, 1.50 mm) were designed, and three different materials, including polyetherketoneketone (PEKK), polymethylmethacrylate (PMMA) resin and resin-infiltrated ceramic, were applied to make the crown. Stress distribution and fatigue of each component of the model under vertical and oblique loadings were analyzed by using finite element method. Non-axial retention analysis was performed on chamfer+non-anatomic crowns, made of PMMA resin, with thicknesses of 0.50, 0.75, 1.00, 1.25 and 1.50 mm. Results: Among the four crown shape designs, the chamfer+non-anatomic type crown showed the lowest von Mises stress and the highest safety factor. By comparing three different materials, the resin-infiltrated ceramic group showed obvious stress concentration on the buccal edge of the crown and the PEKK group showed stress concentration in the adhesive layer. Results of non-axial retention analysis showed that the torques required by the crowns with five thicknesses at the same rotation angle were as follows: 4 856.1, 4 038.1, 3 497.3, 3 256.3 and 3 074.3 N⋅m, respectively. The comparison of areas of the adhesives fracture among groups were as follows: 0.5 mm group < 0.75 mm group < 1.00 mm group < 1.25 mm group < 1.50 mm group. Conclusions: In the design of nonmetallic crowns for primary molars, the edge of the crown should be designed as chamfer, the shape of the inner crown should be non-anatomical and the minimum preparation amount of the occlusal surface should be 1.00 mm. Among the three materials, PMMA resin, of which elastic modulus is similar to the dentin and the dental adhesive, might be the most suitable material for the crowns of primary molars.

Clinical outcomes analysis of fertility-preserving therapy for atypical endometrial hyperplasia and early endometrial carcinoma / 中华肿瘤杂志

Objective: To analyze the clinical efficacy of fertility-preserving therapy in patients with atypical endometrial hyperplasia (AEH) and early endometrial carcinoma (EC). Methods: The general condition, pathological type, treatment plan, tumor outcomes and pregnancy outcomes of 110 patients with AEH and EC treated with fertility-preserving therapy in Peking University People's Hospital from December 2005 to September 2019 were retrospectively analyzed. Kaplan-Meier and Log rank tests were used for survival analysis. Results: The response rate of 110 cases of AEH (62 cases) and EC (48 cases) was 94.5% (104/110) after fertility-preserving therapy. There were 93 cases (84.5%) achieved complete response and 11 cases (10.0%) achieved partial response, and the recurrence rate was 29.0% (27/93). The complete response rates of AEH and EC were 90.3% (56/62) and 77.1% (37/48), respectively, without significant difference (P=0.057). The recurrence rates of EC were significantly higher than that of AEH (40.5% vs 21.4%; P=0.022). Forty-one patients with complete response had pregnancy intention, the pregnancy rate was 70.7% (29/41), and the live birth rate was 56.1% (23/41). The live birth rate of AEH was 68.2% (15/22) and that of EC was 42.1% (8/19), the difference was statistically significant (P=0.032). The pathological type was related with the recurrence (P=0.044). Conclusions: Patients with AEH and EC can obtain high complete response rate and pregnancy rate after fertility-preserving therapy. The recurrence rate of EC is higher than that of AEH, while the live birth rate of AEH is higher than that of EC.

YU Tian-yuan's experience in the clinical application of Danzhong (CV 17) for mental illness / 中国针灸

To summarize YU Tian-yuan's experience of applying Danzhong (CV 17) for mental illness in acupuncture and tuina. YU Tian-yuan uses Danzhong (CV 17) alone or in combination with other acupoints to treat mental illnesses such as insomnia, palpitation and chest distress. Professor YU emphasizes 4 tips when treating diseases, nourishing the heart to tranquilize by light stimulation; regulating spirit by combined stimulation; leaving the acupoints and holding on the meridian for a wide range of stimulation; using rubbing and pushing manipulation in several directions for regulating qi to soothe the chest. And in clinical practice, formed a unique therapy to treat mental illness.

Initial establishment of digital reference standardized crown models of the primary teeth / 北京大学学报(医学版)

OBJECTIVE@#To explore the construction process of the digital reference crown models, and to initially establish the digital reference crown models of the primary teeth to lay the foundation for the establishment of the standardized crown models and the future related applications of computer-aided design/computer-aided manufacture (CAD/CAM) technology to pediatric dentistry.@*METHODS@#This study randomly selected children who were caries free, aged from 4 to 5 years in several kindergartens of Haidian District of Beijing.Plaster dental models were made for the children after taking complete impressions.The digital dental models were reconstructed by using the three-dimensional (3D) dental model scanner.And then, Geomagic Studio, a 3D reverse engineering software, was employed to extract the single dental crown data, the mesiodistal and buccolingual diameters and the height of the crowns were measured.The object was reduced or enlarged by a numerical factor, and then the size of each dental crown was standardized.A total of 3-5 points features on the crown were created, and all the objects were aligned through the functions of feature-based alignment.Finally, through average-based object creation and smoothing, the digital models of reference crowns of the primary teeth were established.@*RESULTS@#A total of 40 plaster dental models from 16 boys and 26 girls were selected out for our further study.The digital dental models were reconstructed, and the mesiodistal and buccolingual diameters and the height of the crowns were measured by using reverse engineering technology.Comparing the results of using mesiodistal diameter, buccolingual diameter and height as the standards, we chose the mesiodistal diameters of crowns to do the standardization, and successfully established the digital reference models of 20 primary teeth crowns with detailed surface characteristics.@*CONCLUSION@#In this study, the digital reference crown models of the primary teeth were established by reverse engineering technology, providing reference value for the standardized crown models and application for clinical practice, scientific research and teaching.Furthermore, this study also contributes to the extensive application of CAD/CAM technology in pediatric dentistry and the development of CAD/CAM dental systems with independent intellectual property rights.

Preliminary clinical application verification of complete digital workflow of design lips symmetry reference plane based on posed smile / 北京大学学报(医学版)

OBJECTIVE@#To automatically construct lips symmetry reference plane (SRP) based on posed smile, and to evaluate its advantages over conventional digital aesthetic design.@*METHODS@#Eighteen subjects' three-dimensional facial and dentition data were gathered in this study. The lips SRP of experimental groups were used with the standard weighted Procrustes analysis (WPA) algorithm and iterative closest point (ICP), respectively. A reference plane defined by experts based on regional ICP algorithm, served as the truth plane. The angle error values between the lips SRP of WPA algorithm in the experimental groups and the truth plane were evaluated in this study, and the lips SRP of ICP algorithm of the experimental groups was calculated in the same way. The lips SRP based on posed smile as a reference for aesthetic design and evaluate preliminary clinical application.@*RESULTS@#The average angle error between the lips SRP of WPA algorithm and the truth plane was 1.78°±1.24°, which was smaller than that between the lips SRP of ICP and the truth plane 7.41°±4.31°. There were significant differences in the angle errors among the groups (P < 0.05). In the aesthetic design of anterior teeth, automatically constructing the lips SRP of WPA algorithm based on posed smile and the original symmetry plane by re-ference compared with the prosthetic design, the subjects' scores on the lips SRP of WPA algorithm based on posed smile (8.48±0.57) were higher than those on the original symmetry plane (5.20±1.31).@*CONCLUSION@#Automatically constructing the lips SRP of WPA algorithm based on posed smile was more accurate than ICP algorithm, which was consistent with the truth plane. Moreover, it can provide an important reference for oral aesthetic diagnosis and aesthetic analysis of the restoration effect. In the aesthetic design of anterior teeth, automatically constructing the lips SRP of WPA algorithm based on posed smile can improve the patients' satisfaction in esthetic rehabilitation.

In vitro evaluation of positioning accuracy of trephine bur at different depths by dynamic navigation / 北京大学学报(医学版)

OBJECTIVE@#To evaluate the accuracy of trephine bur drilling at different depths guided by dynamic navigation system in 3D printing in vitro model.@*METHODS@#A model at the depth of 5 mm, 10 mm, and 15 mm from the outer surface of which hemispherical cavities was reserved and the 3D printing technology was used to make the standardized model with Veroclear resin. The cone beam CT (CBCT) was taken and the data were imported into the dynamic navigation software (DCARER, China) to establish navigation path programming. Under the guidance of dynamic navigation, a trephine bur with a diameter of 4.5 mm was used to complete the access operation. At each depth, 10 approaches were completed. The postoperative model CBCT was taken. The approach trajectory under navigation was reconstructed and compared with the designed path. The two-dimensional distance deviation, depth deviation, three-dimensional distance deviation, and angle deviation between the actually prepared path and the designed path were calculated.@*RESULTS@#At the depth of 5 mm, the two-dimensional distance deviation between the end position of the prepared path and the designed path was (0.37±0.06) mm, the depth deviation was (0.06±0.05) mm, the three-dimensional distance deviation was (0.38±0.07) mm, and the angle deviation was 2.46°±0.54°; At the depth of 10 mm, the four deviations between the end position of prepared path and the designed path were (0.44±0.05) mm, (0.16±0.06) mm, (0.47±0.05) mm, and 2.45°±1.21°, respectively; At the depth of 15 mm, the four deviations were (0.52±0.14) mm, (0.16±0.07) mm, (0.55±0.15) mm, and 3.25°±1.22°, respectively. With the increase of entry depth, the three-dimensional and depth accuracy of dynamic navigation system decreased (P < 0.01), and the positioning angle deviation had no relation with the entry depth (P>0.01).@*CONCLUSION@#Dynamic navigation technology can achieve high positioning accuracy in the depth range of 15 mm, but its deviation increases with the increase of entry depth.

Deep learning-assisted construction of three-demensional facial midsagittal plane / 北京大学学报(医学版)

OBJECTIVE@#To establish a deep learning algorithm that can accurately determine three-dimensional facial anatomical landmarks, multi-view stacked hourglass convolutional neural networks (MSH-CNN) and to construct three-dimensional facial midsagittal plane automatically based on MSH-CNN and weighted Procrustes analysis algorithm.@*METHODS@#One hundred subjects with no obvious facial deformity were collected in our oral clinic. Three-dimensional facial data were scanned by three-dimensional facial scanner. Experts annotated twenty-one facial landmarks and midsagittal plane of each data. Eighty three-dimensional facial data were used as training set, to train the MSH-CNN in this study. The overview of MSH-CNN network architecture contained multi-view rendering and training the MSH-CNN network. The three-dimensional facial data were rendered from ninety-six views that were fed to MSH-CNN and the output was one heatmap per landmark. The result of the twenty-one landmarks was accurately placed on the three-dimensional facial data after a three-dimensional view ray voting process. The remaining twenty three-dimensional facial data were used as test set. The trained MSH-CNN automatically determined twenty-one three-dimensional facial anatomical landmarks of each case of data, and calculated the distance between each MSH-CNN landmark and the expert landmark, which was defined as position error. The midsagittal plane of the twenty subjects' could be automatically constructed, using the MSH-CNN and Procrustes analysis algorithm. To evaluate the effect of midsagittal plane by automatic method, the angle between the midsagittal plane constructed by the automatic method and the expert annotated plane was calculated, which was defined as angle error.@*RESULTS@#For twenty subjects with no obvious facial deformity, the average angle error of the midsagittal plane constructed by MSH-CNN and weighted Procrustes analysis algorithm was 0.73°±0.50°, in which the average position error of the twenty-one facial landmarks automatically determined by MSH-CNN was (1.13±0.24) mm, the maximum position error of the orbital area was (1.31±0.54) mm, and the minimum position error of the nasal area was (0.79±0.36) mm.@*CONCLUSION@#This research combines deep learning algorithms and Procrustes analysis algorithms to realize the fully automated construction of the three-dimensional midsagittal plane, which initially achieves the construction effect of clinical experts. The obtained results constituted the basis for the independent intellectual property software development.

The role of LncRNA00602 in Ad36-induced differentiation of adipocytes / 中华内分泌代谢杂志

Objective:To investigate the possible role of long non-coding RNA (LncRNA) 00602 in promoting browning in adipocytes induced by adenovirus type 36 (Ad36).Methods:According to Ad36 infection, adipose tissue samples of obese patients were divided into Ad36-negative group and Ad36-infected group. Realtime fluorescent quantitative PCR (qRT-PCR) was used to detect the changes in the expression of LncRNA00602 mRNA in omental adipose tissue of the two groups, and analyze the differences between the two groups. The correlation between waist-to-hip ratio, systolic blood pressure, diastolic blood pressure, fasting blood glucose, triacylglyceride and other indicators of the patients in the group with LncRNA00602 mRNA expression were analyzed. HE staining was used to detect the size of adipocytes in the omental adipose tissue of the Ad36 negative group and the Ad36 infection group. qRT-PCR and Western blotting were used to detect the mRNA and protein expression levels of uncoupling protein 1 (UCP1) and PR domain containing 16 (PRDM16) in omental adipose tissue of two groups of patients. Human adipose-derived stem cells (hADSC) were isolated and cultured, using Ad36 to induce differentiation, and divided into control group and LncRNA00602 knockdown group. On 0, 2, and 4 days after LncRNA00602 knockdown, fluoroboron dipyrrole (BODIPY) and mitochondrial red fluorescence (Mito-Tracker Red) were used to stain intracellular lipid droplets and mitochondria. At the same time, qRT-PCR and Western blotting were used to detect changes in the expression of UCP1 and PRDM16.Results:The expression of LncRNA00602 gene in the Ad36 infection group was higher than that in the Ad36 negative group (all P<0.05). The expression of LncRNA00602 in the Ad36 negative group was not significantly different from the above clinical indicators, while the expression of LncRNA00602 was negatively correlated with serum fasting blood glucose and triacylglyceride ( r=-0.522, -0.486, P<0.05) in the Ad36 infection group; HE staining showed that the average adipocyte area of the Ad36 infection group was smaller than that of the Ad36 negative group. At the same time, UCP1 and PRDM16 gene expression were higher than the negative group (all P<0.05). At the cellular level, on the 2nd and 4th days after knockdown of LncRNA00602, the lipid droplet area of adipocytes in the LncRNA00602 knockdown group was larger than that of the control group, the number of mitochondria decreased compared with the control group, and difference was statistically significant ( P<0.05 or P<0.01); Compared with the control group, there was significantly lower expression of the browning marker genes UCP1, PRDM16, and protein in the adipocytes in the LncRNA00602 knockdown group (all P<0.05). Conclusion:In Ad36-induced adipocyte differentiation, LncRNA00602 may positively regulate the expression of UCP1, PRDM16 and lipid droplet metabolism, and promote the browning of adipocytes.

A method for constructing three-dimensional face symmetry reference plane based on weighted shape analysis algorithm / 北京大学学报(医学版)

OBJECTIVE@#To establish a novel method based on three-dimensional (3D) shape analysis and weighted Procrustes analysis (WPA) algorithm to construct a 3D facial symmetry reference plane (SRP), automatically assigning weight to facial anatomical landmarks. The WPA algorithm suitability for commonly observed clinical cases of mandibular deviation were analysed and evaluated.@*METHODS@#Thirty patients with mandibular deviation were recruited for this study. The 3D facial SRPs were extracted independently based on original-mirror alignment method. Thirty-two anatomical landmarks were selected from the overall region by three times to obtain the mean coordinate. The SRP of experimental groups 1 and 2 were using the standard Procrustes analysis (PA) algorithm and WPA algorithm, respectively. A reference plane defined by experts based on regional iterative closest point (ICP) algorithm, served as the ground truth. Three experts manually selecting facial regions with good symmetry for original model, and common region was included in the study. The angle error values between the SRP of WPA algorithm in the experimental group 1 and the truth plane were evaluated in this study, and the SRP of PA algorithm of experimental group 2 was calculated in the same way. Statistics and measurement analysis were used to comprehensively evaluate the clinical suitability of the WPA algorithm to calculate the SRP. A paired t-test analysis (two-tailed) was conducted to compare the angles.@*RESULTS@#The average angle error between the SRP of WPA algorithm and the ground truth was 1.53°±0.84°, which was smaller than that between the SRP of PA and the ground truth (2.06°±0.86°). There were significant differences in the angle errors among the groups (P < 0.05). For the patients with severe mandibular deviation that the distance between pogonion and facial midline greater than 12 mm, the average angle error of the WPA algorithm was 0.86° smaller than that of the PA algorithm.@*CONCLUSION@#The WPA algorithm, based on weighted shape analysis, can provide a more adaptable SRP than the standard PA algorithm when applied to mandibular deviation patients and preliminarily simulate the diagnosis strategies of clinical experts.

Radiography study on osteotome sinus floor elevation with placed implant simultaneously with no graft augmentation / 北京大学学报(医学版)

OBJECTIVE@#To investigate the change of endo-sinus bone height and bone volume in osteotome sinus floor elevation (OSFE) without bone graft but placing implants simultaneously by using cone beam computed tomography (CBCT) and three dimensional analysis, and to find the impacting factors on endo-sinus bone augmentation.@*METHODS@#OSFE was performed in 38 edentulous patients with missing teeth at posterior maxillary region, and 44 implants were placed and referred for OSFE using no graft materials. CBCT was performed pre-surgery and 9－68 months post-surgery when the patients encountered another implant surgery. The gained bone height at mesial, distal, buccal and palatal sites around the implant in sinus were measured, volumetric measurements of the endo-sinus gained bone volume (ESGBV) in the elevated region were calculated by Mimics software. Univariate analysis and multiple linear regression were performed to investigate the impacting factors on the gained bone height and ESGBV. Marginal bone loss was recorded according to the periapical radiography after implant restoration.@*RESULTS@#The mean residual bone height (RBH) pre-surgery was (3.41±1.23) mm, the mean protruded length (PL) into sinus of implant post-surgery was (3.41±1.28) mm, the mean endo-sinus gained bone height was (2.44±1.23) mm at distal sites, (2.88±1.20) mm at mesial sites, (2.83±1.22) mm at buccal sites and (2.96±1.16) mm at palatal sites, the mean endo-sinus gained bone height at distal sites was significantly lower than the other three sites (P < 0.05). The average endo-sinus gained bone height was (2.78±1.13) mm. The mean ESGBV was (122.15± 73.27) mm3. Univariate analysis showed the more RBH, the less bone height gained in sinus, which existed at buccal, lingual, mesial and distal sites (P < 0.001), and the more RBH, the smaller ESGBV gained (P=0.012). The ESGBV was significantly higher in the subjects whose bone generation period was more than 24 months than those whose bone generation period less than 24 months (P=0.034). The more PL, the more bone height and ESGBV gained (P=0.008). Multivariate analysis showed after adjusting factors of gender, age, smoking, width of sinus floor, thickness of sinus membrane pre-surgery, diameter and length of the implant, PL and bone generation period was positively correlated with mean endo-sinus gained bone height and ESGBV, while RBH negatively correlated with mean endo-sinus gained bone height. During the follow-up, the mean marginal bone loss was 0 (0－1.41) mm and all the implants loaded successfully.@*CONCLUSION@#OSFE without bone graft but with placed implant simultaneously can increase endo-sinus gained bone height and ESGBV. RBH, PL and bone generation period are the significant factors impacting endo-sinus bone augmentation.

In vitro evaluation of the application of digital individual tooth tray in the impression making of mandibular full-arch crown abutments / 北京大学学报(医学版)

OBJECTIVE@#To establish a method for the production of digital individual tooth tray based on three-dimensional (3D) scan, computer-aided design (CAD) and 3D printing, and to evaluate the effect of impression taking of full-arch crown abutments by digital individual tooth tray technique and conventional method through in vitro study.@*METHODS@#The full crown preparation was performed on all the fourteen resin teeth in a standard model of mandibular dentition. The surface data of prepared abutments was collected by 3D scanning. A new project was created in a dental CAD software including all the fourteen teeth in the mandibular dentition. The design modules of anatomy crown and coping were selected for each tooth. The dentition was divided for three sections: right posterior teeth, anterior teeth, and left posterior teeth areas. The connector design was added between the abutments within the same section. The scanned data of the abutments were imported. The occlusal plane and insertion path were determined. The position of margin line, as well as the shape of anatomy crown and connector as the main body of the individual tooth tray were designed for each abutment. The shape of coping was generated as the space for holding the impression material. The finalized data of the main body was imported into Geomagic software. The retentive attachment was added at the external surface and the tissue stop was formed at the internal surface. The completed individual tooth tray was manufactured by 3D printing with resin material. The data of full-arch crown abutments were modified and printed. The conventional dentition trays A and B, as well as digital individual tooth tray were designed and printed for four copies each. The polyether impressions of the full-arch abutments were made by conventional one-step method using dentition tray A, and by sectional-impression technique using digital individual tooth tray and dentition tray B for four times each. The time spent for each impression taking and the numbers of defects at the shoulder and axial/occlusal surface in each impression were recorded. The impression quality of each abutment was evaluated. The overall quality distribution and the pass rate of abutments between the two methods were analyzed.@*RESULTS@#The impressions made by conventional method had more defects at shoulder than those made by digital individual tooth tray technique. No difference of the number of defects at axial/occlusal surface between the two methods was observed. The digital individual tooth tray technique for the full-arch abutment impression exhibited higher pass rate of abutments and better quality of impression, compared with conventional methods.@*CONCLUSION@#A new method for the production of digital individual tooth tray based on digital scanning, CAD and 3D printing was established. Compared with conventional method, using digital individual tooth tray technique for impression taking of full-arch abutments can achieve better effect.

Discussion on Using Quality Control Circle to Improve the Qualified Rate of Anesthesia Prescription in Our Hospital / 中国药学杂志

OBJECTIVE: To explore the application effect of quality control circle management in improving the qualified rate of anesthetic drugs prescription in hospital. METHODS: The quality control circle was established to explore the causes of the unqualified anesthetic drugs prescription in our hospital by using the 80/20 rule and fish-bone diagram. The measures to improve the prescription pass rate were determined, and the changes of the prescription pass rate before and after QCC management were compared through the implementation and review of the measures. RESULTS: Using the management of quality control circle, the prescription quality of inpatient anesthetic drugs was significantly improved in our hospital in 2018 and the qualified rate increased from 70.07% in 2017 to 2018 97.78% above target value of 6.69%. After continuous quality control circle management, the qualified rate of prescription increased to 99.33% in the first three quarters of 2019. CONCLUSION: The development of QCC can effectively improve the qualified rate of anesthetic drugs prescription in hospital, not only standardizing the use of anesthetic drugs, promoting drug safety of patients, but also improving the comprehensive quality of pharmacists and the quality of hospital pharmaceutical care.