OBJECTIVE: To develop an original-mirror alignment associated deep learning algorithm for intelligent registration of three-dimensional maxillofacial point cloud data, by utilizing a dynamic graph-based registration network model (maxillofacial dynamic graph registration network, MDGR-Net), and to provide a valuable reference for digital design and analysis in clinical dental applications. METHODS: Four hundred clinical patients without significant deformities were recruited from Peking University School of Stomatology from October 2018 to October 2022. Through data augmentation, a total of 2 000 three-dimensional maxillofacial datasets were generated for training and testing the MDGR-Net algorithm. These were divided into a training set (1 400 cases), a validation set (200 cases), and an internal test set (200 cases). The MDGR-Net model constructed feature vectors for key points in both original and mirror point clouds (X, Y), established correspondences between key points in the X and Y point clouds based on these feature vectors, and calculated rotation and translation matrices using singular value decomposition (SVD). Utilizing the MDGR-Net model, intelligent registration of the original and mirror point clouds were achieved, resulting in a combined point cloud. The principal component analysis (PCA) algorithm was applied to this combined point cloud to obtain the symmetry reference plane associated with the MDGR-Net methodology. Model evaluation for the translation and rotation matrices on the test set was performed using the coefficient of determination (R²). Angle error evaluations for the three-dimensional maxillofacial symmetry reference planes were constructed using the MDGR-Net-associated method and the "ground truth" iterative closest point (ICP)-associated method were conducted on 200 cases in the internal test set and 40 cases in an external test set. RESULTS: Based on testing with the three-dimensional maxillofacial data from the 200-case internal test set, the MDGR-Net model achieved an R² value of 0.91 for the rotation matrix and 0.98 for the translation matrix. The average angle error on the internal and external test sets were 0.84°±0.55° and 0.58°±0.43°, respectively. The construction of the three-dimensional maxillofacial symmetry reference plane for 40 clinical cases took only 3 seconds, with the model performing optimally in the patients with skeletal Class Ⅲ malocclusion, high angle cases, and Angle Class Ⅲ orthodontic patients. CONCLUSION This study proposed the MDGR-Net association method based on intelligent point cloud registration as a novel solution for constructing three-dimensional maxillofacial symmetry reference planes in clinical dental applications, which can significantly enhance diagnostic and therapeutic efficiency and outcomes, while reduce expert dependence.
Humans ; Deep Learning ; Algorithms ; Imaging, Three-Dimensional/methods* ; Male ; Female ; Maxilla/diagnostic imaging* ; Adult

OBJECTIVES: This study aimed to evaluate the repeatability and reliability of a self-developed domestic wireless surface electromyography (sEMG) system (Oralmetry) in assessing the activity of the temporalis and masseter muscles to provide theoretical support for its clinical application. METHODS: Twenty-two volunteers were recruited. Through multiple repeated measurements, the sEMG signals of bilateral anterior temporalis and masseter muscles during maximum voluntary clenching were collected using the self-developed sEMG device, Oralmetry, and two commercial sEMG devices (Zebris and Teethan), filtered, screened, and standardized. Seven sEMG indicators for assessing masticatory muscle function were calculated. The intraclass correlation coefficient (ICC) was used to evaluate the repeatability of the measurements from the three sEMG devices, and statistical analysis was conducted to compare the consistency of the seven sEMG indicators obtained from the devices. RESULTS: Among the 22 participants, the ICC values of the repeated measurements from the three sEMG devices ranged from 0.88 to 0.99. The measurements of three sEMG indicators (antero-posterior coeffificient, percentage overlapping coeffificient_MM, and percentage overlapping coeffificient_TA) obtained by Zebris were significantly different from those obtained by Oralmetry and Teethan (P<0.05). No significant differences in the measurements of the seven sEMG indicators were found between Oralmetry and Teethan. CONCLUSIONS Oralmetry and the two commercial sEMG devices demonstrated good repeatability in capturing sEMG indicators for evaluating masticatory muscle function. In particular, Oralmetry showed the highest ICC values. All three devices also exhibited good consistency in measuring sEMG indicators, and a high agreement was observed between the two wireless sEMG devices (Oralmetry and Teethan). These findings provide theoretical support for the clinical application of Oralmetry.
Humans ; Electromyography/methods* ; Masseter Muscle/physiology* ; Masticatory Muscles/physiology* ; Wireless Technology ; Reproducibility of Results ; Temporal Muscle/physiology* ; Male ; Adult ; Female ; Young Adult

Objective This study proposes a chairside digital design and manufacturing method for band and loop space maintainers and preliminarily validates its clinical feasibility.Methods Clinical cases of 10 children requiring space maintenance caused by premature loss of primary teeth were collected.Intraoral scan data of the affected children were also collected to establish digital models of the missing teeth.Using a pediatric band and loop space maintainer de-sign software developed by our research team,a rapid personalized design of band and loop structures was achieved,and a digital model of an integrated band and loop space maintainer was ultimately generated.A chairside space maintainer was manufactured through metal computer numerical control machining for the experimental group,whereas metal 3D printing in the dental laboratory was used for the control group.A model fitting assessment was conducted for the space maintainers of both groups,and senior pediatric dental experts were invited to evaluate the clinical feasibility of the space maintainers with regard to fit and stability using the visual analogue scale scoring system.Statistical analysis was also performed.Results The time spent in designing and manufacturing the 10 space maintainers of the experimental group was all less than 1 h.Statistical analysis of expert ratings showed that the experimental group outperformed the control group with regard to fit and stability.Both types of space maintainers met clinical requirements.Conclusion The chairside digital design and manufacturing method for pediatric band and loop space maintainers proposed in this study can achieve same-day fitting of space maintainers at the first appointment,demonstrating good clinical feasibility and significant potential for clinical application.

Objective:To explore the method of obtaining the key parameters of the average value articulator in healthy people based on mandibular movement trajectory data, with a view to providing a reference for the clinical application of the average value articulator.Methods:One hundred healthy volunteers (42 males and 58 females) with individual normal occlusion, aged 18-55 years old, who met the inclusion criteria were recruited from Beijing, and their mandibular movement trajectory data were collected. The left and right sagittal condylar inclination(SCI) and transversal condylar inclination(TCI) were obtained from the values of the articulator parameters which were generated in the mandibular movement analysis system.The SCI and TCI were grouped by gender and calculated separately for the two groups and the overall sample; the gender differences in the two parameters and the differences between the mean values of the two parameters and the average value articulator empirical values (35° for SCI and 15° for TCI) for the overall sample were compared.Results:The differences between SCI (35.8°±7.4°) and TCI [11.2° (11.3°)] in males and the corresponding parameters [35.6°±8.3° and 10.8° (9.5°), respectively] in females were not statistically significant ( t=0.10, P=0.922; Z=-0.60, P=0.552); the overall sample SCI (35.7°±7.9°) did not differ statistically from the average value articulator empirical value ( t=1.23, P=0.221), and the overall sample TCI [10.9° (10.3°)] was significantly smaller than the average value articulator empirical value ( W=5 825.00, P<0.001). Conclusions:The mandibular movement trajectory data of 100 adults with individual normal occlusion in this study shows that the gender factor does not affect the setting of the key parameters of the average value articulator, the SCI of the average value articulator empirical values is appropriate, and the TCI has the possibility of being on the large side. In the clinical use of the articulator to assist in the design of restorations, the parameter values should be rationally adjusted according to the actual situation of the patient′s dentition and mandibular movement.

Objective:To investigate the efficacy of continuous irrigation and drainage combined with lesion debridement surgery in the treatment of purulent bone and joint infections in children.Methods:A case-control study was conducted to retrospectively analyze the clinical data of 76 children with purulent bone and joint infections who received treatment at Hangzhou Children's Hospital from January 2021 to October 2022. Based on different treatment methods, these children were divided into a control group and an observation group, with 38 cases in each group. The control group received lesion debridement surgery, while the observation group underwent continuous irrigation and drainage combined with lesion debridement surgery. The clinical outcomes of the two groups were compared.Results:The total response rate in the observation group was 97.37% (37/38), which was significantly higher than that in the control group [76.32% (29/38), χ2 = 7.36, P < 0.05]. After treatment, the white blood cell count, erythrocyte sedimentation rate, and percentage of neutrophils in the observation group were (4.32 ± 0.95) × 10 9/L, (14.20 ± 2.50) mm/h, and (52.12 ± 8.45)%, respectively, all of which were significantly lower than those in the control group [(5.68 ± 1.02) × 10 9/L, (22.35 ± 3.35) mm/h, and (66.65 ± 6.20)%, t = 6.01, 12.01, 8.54, all P < 0.05]. The levels of interleukin-6, C-reactive protein, procalcitonin, and tumor necrosis factor-α in the observation group were (5.20 ± 1.02) ng/L, (8.20 ± 1.11) mg/L, (0.80 ± 0.12) μg/L, and (3.20 ± 1.02) ng/L, respectively, which were significantly lower than those in the control group [(8.12 ± 1.10) ng/L, (14.34 ± 2.20) mg/L, (1.12 ± 0.20) μg/L, and (7.50 ± 1.12) ng/L, t = 11.99, 15.36, 8.45, 17.49, all P < 0.05). At 1 week, 1 month, and 3 months after treatment, the Visual Analog Scale scores in the observation group were significantly lower than those in the control group ( t = 3.14, 2.33, 11.36, all P < 0.05). The recurrence rate in the observation group was significantly lower than that in the control group [2.63% (1/38) vs. 21.05% (8/38), χ2= 4.53, P < 0.05). Conclusion:Continuous irrigation and drainage combined with lesion debridement surgery is more effective for treating purulent bone and joint infections in children than lesion debridement surgery alone. This combined therapy can more effectively reduce inflammatory responses, alleviate pain, and lead to a lower recurrence rate.

Objective:To establish an intelligent registration algorithm under the framework of original-mirror alignment algorithm to construct three-dimensional (3D) facial midsagittal plane automatically. Dynamic Graph Registration Network (DGRNet) was established to realize the intelligent registration, in order to provide a reference for clinical digital design and analysis.Methods:Two hundred clinical patients without significant facial deformities were collected from October 2020 to October 2022 at Peking University School and Hospital of Stomatology. The DGRNet consists of constructing the feature vectors of key points in point original and mirror point clouds (X, Y), obtaining the correspondence of key points, and calculating the rotation and translation by singular value decomposition. Original and mirror point clouds were registrated and united. The principal component analysis (PCA) algorithm was used to obtain the DGRNet alignment midsagittal plane. The model was evaluated based on the coefficient of determination (R 2) index for the translation and rotation matrix of test set. The angle error was evaluated on the 3D facial midsagittal plane constructed by the DGRNet alignment midsagittal plane and the iterative closet point (ICP) alignment midsagittal plane for 50 cases of clinical facial data. Results:The average angle error of the DGRNet alignment midsagittal plane and ICP alignment midsagittal plane was 1.05°±0.56°, and the minimum angle error was only 0.13°. The successful detection rate was 78% (39/50) within 1.50° and 90% (45/50) within 2.00°.Conclusions:This study proposes a new solution for the construction of 3D facial midsagittal plane based on the DGRNet alignment method with intelligent registration, which can improve the efficiency and effectiveness of treatment to some extent.

OBJECTIVE: To explore the feasibility of using indocyanine green angiography in mapping the superficial temporal vessels and assisting design and harvesting of the superficial temporal artery based forehead flap. METHODS: A clinical data of 14 patients with facial soft tissue defects repaired with superficial temporal artery based forehead flaps between October 2015 and November 2022 was retrospectively analyzed. There were 9 males and 5 females with a median age of 9.5 years (range, 3-38 years). The forehead flaps were used to reconstruct facial soft tissue defects following excision of facial scar (8 cases) or congenital melanocyte nevus (6 cases). The size of defects ranged from 3 cm×2 cm to 24 cm×9 cm. Before operation, the indocyanine green angiography was used to map the superficial temporal artery and vein, and to analyze the relationship of the arteries and veins. The forehead flaps with unilateral superficial temporal fascia as the pedicle was transferred to repair the small facial defect in 2 cases. The facial pedicle contained the frontal branch of the superficial temporal artery and 2 cm of the superficial temporal fascia around the vessel, and the tiny accompanying vein of the frontal branch of the superficial temporal artery was used as the outflow of the flap. The forehead flaps with the skin pedicle including bilateral or unilateral superficial temporal fascia and the overlying skin was pre-expanded and transferred to repair the large facial defect in 12 cases. The skin pedicle contained the frontal branch of superficial temporal artery and one of main branches of superficial temporal vein. Among the 12 cases, the frontal branch of superficial temporal vein was used as the outflow in 4 cases, and the parietal branch was used as the outflow in 8 cases. The size of the flaps ranged from 3 cm×2 cm to 30 cm×13 cm. The skin pedicles were divided at 3 weeks after the flap transfer. RESULTS: Indocyanine green angiography could clearly showed the course and branching of the superficial temporal artery and vein. Individual differences existed in the location where the frontal branch of the superficial temporal artery entered the forehead. The superficial temporal vein had great variability and did not follow the artery. One patient had expander-related complication, which resulted in 3-cm flap necrosis. The necrotic tissue was debrided and repaired with skin grafting. The other flaps totally survived and the incisions healed by first intention. All patients were followed up 2-24 months, with a median of 11.5 months. The color, texture, and thickness of the flaps matched well with those of recipient sites. Hypertrophic scar was not observed in recipient or donor site. All patients were satisfied with the reconstructive outcomes. CONCLUSION Indocyanine green angiography can clearly visualize the course and the branches of the superficial temporal arteries and veins, which can help surgeons understand the position, distribution, and concomitant relationship of the superficial temporal vessels, and make a rational surgical plan of the forehead flap.
Male ; Female ; Humans ; Child, Preschool ; Child ; Adolescent ; Young Adult ; Adult ; Temporal Arteries/surgery* ; Indocyanine Green ; Forehead/surgery* ; Retrospective Studies ; Skin Transplantation ; Angiography ; Soft Tissue Injuries/surgery* ; Perforator Flap/blood supply* ; Treatment Outcome

OBJECTIVE: To review the research progress of the principle and clinical application of keloid core excision technique. METHODS: The literature on keloid core excision technique at home and abroad in recent years was extensively reviewed, and the principle, development history, indications, advantages and disadvantages of this technique were summarized, and the existing controversies were analyzed. RESULTS: Keloid core excision is a technique to remove the inner fibrous core from the keloid and cover the defect with the keloidal flap. It reduces the wound tension, yields good aesthetic results in the treatment of ear keloids, and reduces the recurrence rate of keloids combining with adjuvant therapies. CONCLUSION The keloid core excision technique has specific advantages, yet its overall efficacy remains controversial. Further studies are imperative to explore the mechanisms regarding keloid recurrence and the vascular supply principles of the keloidal flap. It is also necessary to define appropriate surgical indications and safety protocols of this technique.
Humans ; Keloid/pathology* ; Recurrence ; Surgical Flaps/pathology* ; Plastic Surgery Procedures ; Treatment Outcome

Objective:To investigate the effectiveness of sequential flap transfer technique in the reconstruction of extensive faciocervical scar.Methods:The clinical data of patients with extensive faciocervical scar admitted to the Scar Comprehensive Treatment Center of Plastic Surgery Hospital of Chinese Academy of Medical Sciences from June 2010 to April 2022 were retrospectively analyzed. Pre-expanded medial arm flap or supraclavicular artery perforator plus flap were harvested and used as the first flap to repair the defects left by faciocervical scar resection. Latissimus dorsi myocutaneous flaps or thoracodorsal artery perforator flaps were harvested from the ipsilateral back and used as the second flap to repair the donor sites of the first flap. Donor sites at the back were directly sutured. The survival of flaps, the morphology of donor sites and recipient sites and the scar of donor site were followed up.Results:A total of 13 patients, aged from 5 to 36 years (median age, 14 years), were included, including 8 males and 5 females. Twelve of the 13 cases were post-burn scar, including facial scars in 5 cases, cervical scar in 1 case and faciocervical scar in 6 cases. One case of scar was caused by radiotherapy for facial hemangioma. The size of defects after scar resection and release ranged from 12.0 cm × 8.0 cm to 24.5 cm × 8.0 cm. The operation was successfully completed in all cases. Three pre-expanded supraclavicular artery perforator plus flaps and 10 pre-expanded medial arm flaps, measuring 23.0 cm × 7.0 cm to 27.0 cm ×14.0 cm, were used as the first flap; five latissimus dorsi myocutaneous flaps and eight thoracodorsal artery perforator flaps, measuring 18.0 cm × 7.0 cm to 25.0 cm × 10.0 cm, were used as the second flap. One patient developed hematoma at two days after the pedicle division of medial arm flap and the flap survived completely after removal of the hematoma. Other flaps survived without complications and the incisions were healed in one stage. Patients were followed up for 1 to 48 months, with a median follow-up of 13 months. The color, texture, and thickness of flaps were similar to those of the recipient site. All patients were satisfied with the cosmetic result of recipient sites and donor sites.Conclusion:The sequential flap transfer technique could improve the reconstructive ability of pre-expanded medial arm flap and supraclavicular artery perforator plus flap in surgical treatment of extensive faciocervical scar, minimize the donor site morbidities, assist the closure of donor site and improve the overall outcomes.

Objective:To investigate the effectiveness of sequential flap transfer technique in the reconstruction of extensive faciocervical scar.Methods:The clinical data of patients with extensive faciocervical scar admitted to the Scar Comprehensive Treatment Center of Plastic Surgery Hospital of Chinese Academy of Medical Sciences from June 2010 to April 2022 were retrospectively analyzed. Pre-expanded medial arm flap or supraclavicular artery perforator plus flap were harvested and used as the first flap to repair the defects left by faciocervical scar resection. Latissimus dorsi myocutaneous flaps or thoracodorsal artery perforator flaps were harvested from the ipsilateral back and used as the second flap to repair the donor sites of the first flap. Donor sites at the back were directly sutured. The survival of flaps, the morphology of donor sites and recipient sites and the scar of donor site were followed up.Results:A total of 13 patients, aged from 5 to 36 years (median age, 14 years), were included, including 8 males and 5 females. Twelve of the 13 cases were post-burn scar, including facial scars in 5 cases, cervical scar in 1 case and faciocervical scar in 6 cases. One case of scar was caused by radiotherapy for facial hemangioma. The size of defects after scar resection and release ranged from 12.0 cm × 8.0 cm to 24.5 cm × 8.0 cm. The operation was successfully completed in all cases. Three pre-expanded supraclavicular artery perforator plus flaps and 10 pre-expanded medial arm flaps, measuring 23.0 cm × 7.0 cm to 27.0 cm ×14.0 cm, were used as the first flap; five latissimus dorsi myocutaneous flaps and eight thoracodorsal artery perforator flaps, measuring 18.0 cm × 7.0 cm to 25.0 cm × 10.0 cm, were used as the second flap. One patient developed hematoma at two days after the pedicle division of medial arm flap and the flap survived completely after removal of the hematoma. Other flaps survived without complications and the incisions were healed in one stage. Patients were followed up for 1 to 48 months, with a median follow-up of 13 months. The color, texture, and thickness of flaps were similar to those of the recipient site. All patients were satisfied with the cosmetic result of recipient sites and donor sites.Conclusion:The sequential flap transfer technique could improve the reconstructive ability of pre-expanded medial arm flap and supraclavicular artery perforator plus flap in surgical treatment of extensive faciocervical scar, minimize the donor site morbidities, assist the closure of donor site and improve the overall outcomes.