OBJECTIVE: To compare the registration accuracy of cone beam computed tomography (CBCT) images while registering to virtual craniodentofacial patients based on soft tissue and the dentition registration method. METHODS: Virtual dentofacial patients out of 13 selected participants who needed CBCT scanning were established by impression with a registered-block impression (RBI) based on digital dental images, three-dimensional (3D) facial images and maxillofacial CBCT images. CBCT images were processed in the Mimics software program, establishing the craniofacial virtual patients based on CBCT images (CCTs). Registration between virtual patients from RBI and CCT, using the soft tissue in lower half face (STE) and dentition (DTN) as the reference area, respectively, forming two kinds of virtual craniofacial patients based on digital dental images, 3D facial images and skeletal images of CBCT (hiding the soft tissue and dental casts from CBCT). Three-dimensional deviation analysis was performed in the upper half face and lower half face of facial images from CBCT between two kinds of virtual craniodentofacial patients and compared with 3D facial images from RBI and recorded as root mean square error (RMSE). Paired-t test was used to compare the deviations of RMSEs between the upper and lower half of the face and the upper half of the face of facial images from CCT, respectively, between the two kinds of virtual craniodentofacial patients based on STE and DTN methods. RESULTS: Paired-t tests showed that there was no statistically significant difference between the upper and lower half faces of facial images from CCT between STE and DTN (P>0.05), but the deviation of RMSEs of the upper half face of facial images from CCT in STE was smaller than those in DTN [(1.696±0.420) mm vs. (1.752±0.424) mm, P < 0.01]. CONCLUSION The registration accuracy of CBCT registered in virtual craniodentofacial patients using soft tissue as the reference area was higher.
Humans ; Cone-Beam Computed Tomography/methods* ; Imaging, Three-Dimensional/methods* ; Male ; Face/anatomy & histology* ; Female ; Adult ; Image Processing, Computer-Assisted/methods* ; Young Adult ; User-Computer Interface

Objective To investigate the clinical effect of anterograde percutaneous screw fixation under robot navigation in the treatment of acetabular anterior column fractures.Methods A retrospective analysis was made on 7 cases of anterior acetabular column fractures from April 2021 to January 2023.The traction reduction was conducted by using pelvic"double reverse"traction table,the orthopedic robot-assisted design was carried out to plan the screw entry point and direction,and the antegrade channel cannulated screw was used for internal fixation.Results The operation time was 60-95 min(mean,78 min).The intraoperative blood loss was 5-20 ml(mean,8.6 ml).The number of fluoroscopy was7-11(mean,8.7).The guide needle was unadjusted in 3 cases and adjusted for 1-2 times in 4 cases(once in 2 cases and twice in 2 cases).The actual path deviated from the planned by 0.65-1.50 mm(mean,0.98±0.30 mm).The excellent and good rate of screw position was 100%.X-ray and CT examinations were performed at 48 h after the operation.According to the Matta reduction standard,anatomical reduction was achieved in 6 cases and satisfactory reduction in 1 case.All the 7 cases were followed up for 6-28 months(mean,15 months).At the last follow-up,the Harris score of the hip joint was85-96 points(mean,91.6 points)and the pain of visual analogue scale(VAS)was0.There were no complications such as infection,loosening of internal fixation,or neurological dysfunction.Conclusion Anterograde percutaneous screw fixation under robot navigation in the treatment of acetabular anterior column fractures is safe,effective,and satisfactory.

Objective To explore the learning curve of Bikini incision direct anterior approach total hip arthroplasty(Bikini-THA).Methods Clinical data of 80 cases of Bikini-THA initially completed by an operator skilled in posterolateral approach and direct anterior approach total hip arthroplasty from March 2020 to March 2023 were retrospectively analyzed,and the learning curve was observed by scatter plots of operative time and intraoperative bleeding.They were divided into groups A to D according to the order of surgery,with 20 cases in each group.The operative time,intraoperative bleeding,acetabular abduction angle,anteversion angle,angle between stem and femoral axis,postoperative hip Harris score and complications were compared among the 4 groups.Results After about 40 cases,the decreasing trend of operative time and intraoperative bleeding slowed down and stabilized.The operative time and intraoperative bleeding in the 4 groups were group A＞group B＞groups C and D(P＜0.05),and the differences between the group C and group D were not statistically significant(P＞0.05).The acetabular prosthesis was well-positioned in the 4 groups(abduction angle of 30°-50°,anteversion angle of 5°-25°).The femoral prosthesis center fixation rate(angle between stem and femoral axis ≤3°)was group A＜groups C and D(P=0.003,0.003).The differences in the Harris scores of the hip joints at 2 weeks,1 month,3 months,and 12 months postoperatively of the 4 groups were not statistically significant(P＞0.05),and the efficacy evaluations of the hip joints at 12 months postoperatively were all excellent.There were 5 cases of complications in the group A(2 cases of greater trochanter fracture and 3 cases of lateral femoral cutaneous nerve injury),3 cases of complications in the group B(1 case of greater trochanteric fracture,1 case of lateral femoral cutaneous nerve injury,and 1 case of incision infection),1 case of complications in the group C(lateral femoral cutaneous nerve injury),and no complications in the group D.The follow-up period lasted for 12-26 months,with a mean of(19.4±4.7)months.There were no complications such as dislocation or loosening of the prosthesis.Conclusion The Bikini-THA learning curve was approximately 40 cases.

Objective: To investigate the current situation of using virtual simulation technology in undergraduate schools of stomatology in China, analyze the problems and put forward corresponding improvement suggestions. Methods: A questionnaire survey was conducted among 672 teachers and 3 849 students in undergraduate schools of stomatology in China. Results : 25.81% of all participants had took part in dental virtual simulation courses, and 37.80% of the participants from “Double First-Class” universities had participated in dental virtual simulation courses. 92.12% of the virtual simulation courses were established for undergraduates. "Traditional course + virtual simulation model demonstration" is the main teaching form of virtual simulation courses. Most of the participants were satisfied with the virtual simulation courses offered by their schools. At present, there are also some deficiencies in the virtual simulation courses, such as lack of teaching resources, insufficient interaction and simulation. Conclusion There is difference in the application of virtual simulation technology in undergraduate schools of stomatology in China. The virtual simulation technology is more widely used in "Double First-Class" universities than in ordinary universities. Undergraduates are the main teaching objects of virtual simulation courses. Stomatological schools in China should pay attention to the development and utilization of virtual simulation curriculum resources by cooperation, enrich the form of virtual simulation courses and strengthen the promotion and application of virtual simulation technology in stomatological education.

PURPOSE: The maximum width between the mesial and distal labial transitional line angles, described as “esthetic width” herein, could significantly influence the visual perception of the teeth and smile. This study aimed to conduct biometric research on esthetic width and to explore whether regular distribution exists in the esthetic width of human teeth. MATERIALS AND METHODS: A total of 4,264 maxillary and mandibular anterior teeth were measured using the Geomagic studio software program. The proportions of maxillary to mandibular homonymous teeth and proportions between the adjacent teeth were calculated. Bilateral symmetry and the correlation between the esthetic and mesiodistal widths were both accounted for during the measurement procedures. RESULTS: The mean esthetic widths were 6.773 ± 0.518 mm and 4.329 ± 0.331 mm for maxillary and mandibular central incisors, respectively, 5.451 ± 0.487 mm and 5.008 ± 0.351 mm for maxillary and mandibular lateral incisors, respectively, and 3.340 ± 0.353 mm and 5.958 ± 0.415 mm for maxillary and mandibular canines, respectively. Except for the mandibular canines, no significant difference in esthetic width was found among homonymous teeth from the same jaw. A high linear correlation was found between the esthetic and mesiodistal widths of the same tooth, except for the maxillary canines. Esthetic width proportions among different tooth categories showed some regular patterns, which were similar to those of the mesiodistal width. CONCLUSION Esthetic width is regularly distributed among the teeth in the Chinese population. This could provide an important reference for anterior dental restorations and dimension recovery in esthetic reconstruction of anterior teeth.

Computer aided design, numerically controlled milling, additive manufacturing and other digital technologies have been widely used in clinical practice of prosthodontics. The application of these technologies not only changed the design and manufacturing workflow of removable partial denture (RPD), but also improved the production efficiency of dentures, and changed the design and manufacturing concept of dentures. A large number of researches on computer aided design and computer aided manufacturing (CAD/CAM) of RPD have emerged in recent years, including researches on the properties of selective laser melting metal powder and other new dental materials, the innovative design of retainers, connectors, artificial teeth and other denture components, high precision manufacturing of the RPD framework, denture base and artificial teeth, quantitative laboratory evaluations of the accuracy, adaption and mechanical properties of RPD with new structures and made of new materials, clinical evaluations of RPD and others. This paper introduces these recent developments in CAD/CAM of RPD.

Objective:To investigate the clinical application of cervix-uterine internal target volume (ITV) in volume-modulated arc therapy (VMAT) for cervical cancer under different bladder filling conditions, aiming to obtain more accurate planning target volume (PTV).Methods:Sixty-two patients with cervical cancer receiving radiotherapy rather than surgery were selected and randomly divided into the study ( n=31) and control groups ( n=31). In the study group, individualized ITV, PTV and PTV margin were obtained under three bladder filling status by localization CT scan to compare the VMAT. The target area and organs at risk (OARs) within the target area were statistically compared between two groups. The target missing rate in CBCT, adverse events and short-term efficacy of radiotherapy were analyzed in two groups. Results:There was no significant difference in the volume of target area and OARs in the target area between two groups (both P>0.05). In the study group, the target missing rate and target missing volume were significantly lower compared with those in the control group (both P<0.05). There was no significant difference in the incidence of acute radiation-induced adverse events between two groups ( P>0.05). The 1-, 2-year overall survival and progress-free survival did not significantly differ between two groups (all P>0.05). One patient in the study group had uterine recurrence and 2 cases in the control group. Conclusion:Application of individualized cervix-uterine ITV and PTV in definitive VMAT under different bladder filling conditions can improve the accuracy of target area contouring and improve the local control rate in cervical cancer patients.

Objective:To explore and evaluate a three-dimensional (3D) digital simulated design and implementation technique in esthetic rehabilitation.Methods:Thirty patients with esthetic deficiency, who came to the Department of Prosthodontics, Peking University School and Hospital of Stomatology from December 2017 to July 2019, were recruited and randomly assigned into 2 groups. Four males and 11 females which were (36.0±10.5) years old in the experimental group, 6 males and 9 females which were (32.0±6.7) years old in the control group, were enrolled. In the experimental group, 3D digital simulated design was used to predict the post-treatment effect; and the final restorations were designed duplicating from the pre-treatment digital design confirmed by the patient and milled. In the control group, the final restorations were manufactured by the dental technician according to the design of two-dimensional (2D) digital smile design. The simulation degree of digital design and the similarity between preoperative design and postoperative rehabilitation were scored by the patients with visual analogue scales (VAS) in both groups; and the satisfaction rate to the restorations was evaluated by the patients. The quality of the restorations was accessed by a prosthodontist who did not know the grouping of patients according to the modified criteria of United States Public Health Service (USPHS).Results:Three-dimensional digital simulated design and implementation technique was successfully established. The VAS score on the simulation degree of digital design in the experimental group (8.5±0.5) was higher than that in the control group (7.2±0.7) ( P<0.01); the VAS score on the similarity between preoperative design and postoperative rehabilitation in the experimental group (9.6±0.3) was higher than that in the control group (7.0±0.9) ( P<0.01). The satisfaction rate of the patients to the restorations was significantly higher in the experimental group than in the control group ( P<0.05). There was no significant difference of the quality of the restorations between the two groups on the anatomic form, the marginal adaption and the surface quality ( P>0.05). Conclusions:Three-dimensional digital simulated design and implementation technique can help achieving 3D digital simulated design before treatment and duplication to the final restorations, and can improve the patients′ satisfaction in esthetic rehabilitation.

Objective: To investigate the impact of bladder filling status on the movement of uterine and on the volume of organs at risk(OAR), so as to provide theoretical basis for individualized internal target volume (ITV) and planning target volume (PTV). Methods: Simulation CT images for a total of 27 patients with locally advanced cervical cancer were acquired with empty bladder, 1.0 h after bladder filling, 1.5 h after bladder filling, respectively. The volumes of uterine corpus, cervix, OARs, CTV and PTV 1.0 h after bladder filling were delineated. The impact of bladder filling status on the displacements of cervix and corpus, volumetric changes of rectum, small intestine, and the volumes of small intestine, bladder and rectum within PTV were analyzed. The correlation between bladder filling status and uterine displacement and volume of OAR was also investigated, as well as the volume of cervix and corpus in the PTV with empty bladder and 1.5 h after bladder filling. Results: Bladder filling status is different for individual cases. The maximum movement range of cervix and uterine body with bladder filling state was 0-3.04 cm and 0-4.31 cm respectively. The anterior displacements of corpus (F=7.818, P<0.05), the volumetric changes of blander, as well the volume of bladder and small intestine in the PTV (F=46.197, 44.609, 29.546, P<0.05) were significantly different between different bladder filling status. The bladder filling status was correlated with the displacements of the anterior of corpus, volumetric changes of small intestine, and the volumes of bladder and small intestine within the PTV (r=-0.232, -0.298, 0.915, -0.336, P<0.05). The volumes of cervix and corpus out of the PTV were significantly different between the empty bladder and 1.5 h after bladder filling (t=-1.326, -1.559, P<0.05). Conclusions Bladder filling status was different for individual patients. The displacements of the anterior of the corpus were significantly affected by the bladder filling status. Increasing the anterior margin of PTV was recommended. The consistency of bladder filling status was critical for the precise cervical cancer IMRT.

OBJECTIVE： To provide reference for strengthening clinical application of key monitoring drugs and promoting rational drug use in clinic. METHODS： Based on evidence-based medicine， taking key monitoring drugs Shuxuetong injection as example， clinical evidence of domestic and foreign clinical studies were collected. The included literatures were graded according to the quality of GRADE evidence and recommended strength system. Evidence-based medicine evidence for the indications of Shuxuetong injection were evaluated， and criterion for clinical use of Shuxuetong injection was formulated in Huaihua First People’s Hospital （our hospital）. RESULTS： The main content of criterion for clinical application of Shuxuetong injection formulated by our hospital was that there was A-level evidence support for acute ischemic cerebral infarction， but it was weakly recommended and only used for adjuvant therapy； there was B-level evidence support for anticoagulation （for preventing DVT）， diabetic peripheral nerve lesion， but it was weakly recommended； there was only C-level or D-level evidence support for other indications， it was strongly recommendation against use. CONCLUSIONS： Clinical pharmacists formulate the criterion for clinical application of Shuxuetong injection by evidence quality evaluation method， provide reference for clinical application management of key monitoring drug and play an important effect on rational drug use in clinic.