Objective: To investigate the effect of different visual angles on the accuracy of esthetic defect detection in the dental esthetic zone, clarify the differences in detection accuracy across different tooth positions, esthetic defect types and professional backgrounds of dentists, so as to provide reference for standardized clinical evaluation of dental esthetics. Methods: A total of 114 licensed dentists who participated in various continuing education programs at Peking University School and Hospital of Stomatology from January to December 2025 was enrolled as research subjects. They were divided into the prosthodontics and orthodontics group (n=49) and the other specialties group (n=65). The baseline maxillary anterior teeth photograph from a 26-year-old female volunteer was set as the control. Eleven images with 4 types of esthetic defects (incisal edge position, gingival margin position, tooth long axis and crown width-to-length ratio) were generated, bringing the total number of study images to 12. After rotation at 0°, 90° and 180°, 36 study images were obtained in total. The images were presented to the subjects via slides, with each image shown for 8s. Two evaluation indicators were adopted:defect detection rate and detection accuracy rate. Subjects were required to determine whether there was a esthetic defect in the image and identify the specific type of defect. A correct detection was defined as accurate judgment of both the existence of the defect and the defect type. The values of the two indicators were calculated, and data were analyzed using the chi-square test with SPSS 27.0 software. Results: The detection rate of aesthetic defects among the 36 images ranged from 23.7% (27/114) to 100.0% (114/114), and the accuracy rate ranged from 5.3% (6/114) to 79.8% (91/114). The difference in detection accuracy among different visual angles was statistically significant: the 0° angle had the highest detection accuracy [52.2% (714/1 368)], followed by the 180° angle [45.1% (617/1 368)], and the 90° angle had the lowest accuracy [26.8% (366/1 368)]. For different tooth positions, the detection accuracy of esthetic defects in central incisors [54.2% (741/1 368)] was significantly higher than that in other positions [34.9% (956/2 736)]. The differences in defect detection accuracy under different visual angles were all statistically significant for incisal edge position, gingival margin position, tooth long axis and crown width-to-length ratio (all P<0.017). There was no statistically significant difference in defect detection accuracy between the prosthodontics and orthodontics group and the other specialties group (P>0.05). Conclusions: Visual angle significantly affects the detection accuracy rate of dental esthetic defects, and the 0° angle is more conducive to the identification of aesthetic defects. Tooth position and defect type also have an impact on the detection accuracy rate.
Gingival recession is a common complication of orthodontic treatment, with its occurrence associated with multiple factors such as periodontal phenotype, the width and thickness of keratinized gingiva, alveolar bone morphology, and plaque control. This article first reviews the impact of orthodontic tooth movement, particularly labial tipping of anterior teeth, on periodontal hard and soft tissues. It emphasizes that the risks of orthodontic-related bone fenestration, bone dehiscence, and gingival recession are significantly increased in the presence of a thin gingival biotype, inadequate keratinized gingiva, as well as thinned or deficient buccal bone plates. Subsequently, through case integration, a phased clinical decision-making pathway is proposed: during the three stages of pre-, mid-, and post-orthodontics, baseline risk assessment, judgment of tooth movement direction and tissue volume on the pressure side, the timing and methods of preventive/therapeutic soft/hard tissue augmentation and root coverage procedures are respectively addressed. This approach aims to establish a comprehensive patient management strategy centered on "mucogingival consideration" for orthodontic patients, thereby providing practical guidance for the clinical diagnosis and treatment of orthodontic-related periodontal mucogingival deformities and conditions.
The rapid development of robot-assisted implant surgery in dentistry has led to a significant improvement in the precision and safety of dental implant surgery, and the ensuing problem of associated risk has attracted widespread attention. This article reviews the current status of the application of robot-assisted implant surgery, analyzes the progress of research on related risks, discusses the potential risks, and provides an outlook on the future direction of development.
Objective: To evaluate the clinical efficacy and safety of the multi-wavelength semiconductor laser therapeutic instrument in oral soft tissue incision and gingivectomy. Methods: A total of 156 patients who received mandibular impacted wisdom tooth extraction combined with oral soft tissue incision or gingivectomy at the Stomatological Hospital of Zhejiang University School of Medicine, Zhejiang Hospital and Wenzhou Central Hospital between June 2023 and March 2024 were enrolled and divided into experimental group (n=78) and control group (n=78) by stratified block randomization method. During the operation, the experimental group used the multi-wavelength semiconductor laser therapeutic instrument to complete soft tissue incision and gingivectomy in the surgical area, while the control group used the single-wavelength semiconductor laser therapeutic instrument for the corresponding procedures. Follow-up assessments were conducted one week and one month postoperatively for both groups of patients. Primary outcomes were the excellent and good rate of intraoperative hemostasis and wound healing at one week postoperatively, which were analyzed by non-inferiority test. Secondary outcomes included laser cutting efficiency, convenience of disinfection, operational convenience, operational safety and stability, which were assessed using the Wilcoxon rank-sum test, χ2 test or Fisher's exact probability method. Safety indicator was the incidence of adverse events, which was analyzed using Fisher's exact probability method. Results: Primary efficacy evaluation: the excellent and good rate of intraoperative hemostasis [100.0% (78/78) vs. 100.0% (78/78)] and wound healing [100.0% (78/78) vs 98.7% (77/78)] in the experimental group were both non-inferior to those in the control group. Secondary efficacy evaluation: the laser cutting efficiency in experimental group [(0.08±0.07) mm/s] was significantly higher than that in control group [(0.06±0.04) mm/s] (Z=-2.87, P=0.004). There were no significant differences in disinfection convenience, operational convenience, safety, and stability between the two groups (all P>0.05). Regarding safety evaluation, no adverse events occurred in the experimental group, while 2 cases (2.6%) of mild or moderate adverse events and 1 case (1.3%) of serious adverse events occurred in the control group, with no significant difference (P>0.05). Conclusions: The efficacy and safety of the multi-wavelength semiconductor laser therapeutic instrument are non-inferior to the control products, meeting the standards for clinical validation.
Objective: To evaluate the effects of combining a connective tissue graft (CTG) with immediate implant placement and provisionalization (IIPP) on facial soft tissue contour and alveolar bone remodeling using 3-dimensional quantitative analysis, aiming to provide a clinical reference for decision-making. Methods: This prospective, randomized controlled clinical trial enrolled 31 patients requiring a single immediate implant in the anterior maxilla based on strict inclusion and exclusion criteria. The patients were assigned to the experimental group (n=19, receiving IIPP combined with a CTG harvested from the palate) or the control group (n=12, receiving IIPP alone) and followed up for 12 months. Cone-beam CT and intraoral scanning data were collected and standardized. Evaluation indicators included implant survival rate, complications, horizontal facial bone thickness, vertical facial bone height, vertical changes for gingival margin, vertical changes for mesial and distal papilla height, horizontal changes for facial contour, and pink esthetic score. Statistical analysis was performed. Results: No implant failure occurred in either group during the 12-month follow-up. Regarding bone parameters, at the implant shoulder level (0 mm), the loss of horizontal bone thickness [(1.90±1.19) mm vs. (0.95±0.89) mm] and the reduction in vertical bone height [(1.57±1.08) mm vs. (0.76±0.25) mm] were significantly higher in the experimental group than in the control group (P>0.05). However, no significant differences in bone remodeling were observed between the two groups in the region 1-10 mm apical to the implant platform (all P>0.05). Regarding soft tissue parameters, the facial contour collapse at 0, 1, and 2 mm from the implant shoulder [(0.11±0.43), (0.05±0.44), (0.06±0.59) mm, respectively] and the gingival margin recession [(0.15±0.85) mm] in the experimental group were significantly lower than those in the control group [(0.49±0.17), (0.38±0.16), (0.54±0.43), (0.92±0.84) mm, respectively] (all P>0.05). No significant differences were found between the two groups regarding facial contour changes at -1 and -2 mm from the implant shoulder, or in mesial/distal papilla recession (all P>0.05). Conclusions: Alterations in facial contour and bone tissue were observed in both groups during the 12-month follow-up. The combined use of CTG, IIPP, and customized definitive abutments compensated for facial soft tissue collapse and stabilized gingival height, but failed to maintain the facial alveolar ridge crest bone within 12 months.
Tooth discoloration refers to abnormal changes in tooth color and can be classified into extrinsic staining, intrinsic discoloration, and mixed discoloration. It is a common esthetic concern that may significantly affect patients' appearance and psychological well-being. With the continuous development of minimally invasive esthetic dentistry, more precise and individualized treatment strategies have become available for the management of discolored teeth. This article systematically reviews the etiology, clinical assessment, and advances in minimally invasive esthetic restoration for tooth discoloration. A multidimensional assessment framework based on the degree of color change, the depth of color involvement, and the extent of tooth structure loss is summarized to facilitate clinical decision-making. According to the comprehensive assessment results, individualized treatment strategies, including professional cleaning, tooth bleaching, microabrasion, resin infiltration, direct composite restoration, porcelain veneers, and all-ceramic crowns, should be selected to maximize the preservation of natural tooth structure while achieving esthetic and functional rehabilitation. In addition, the article discusses material selection, adhesive strategies, and long-term maintenance from the perspective of biological stability, aiming to provide a reference for standardized, minimally invasive, and individualized esthetic management of discolored teeth.
Adult dentition diastemata are induced by multiple factors including congenital developmental abnormalities, pathological remodeling of periodontal tissue, dentition defects, occlusal trauma and systemic metabolic diseases, and are frequently accompanied by a series of complications such as impaired masticatory function, compromised anterior esthetics and progressive periodontal destruction. Due to decreased alveolar bone remodeling activity and prolonged tooth movement cycle in adults, monodisciplinary treatment cannot simultaneously achieve balanced function, satisfactory esthetics and long-term dental arch stability. This paper systematically describes the classification criteria of adult dentition diastemata and establishes a hierarchical clinical decision-making system. Four clinical protocols are elaborated, namely orthodontic treatment alone, combined orthodontic-aesthetic restoration, orthodontic-implant rehabilitation, and integrated periodontal-orthodontic-restorative multidisciplinary therapy. A three-tiered standard for therapeutic efficacy evaluation is formulated. Patients are stratified into low-risk, medium-risk and high-risk groups based on periodontal status, severity of bone defects and systemic risk factors, with differentiated follow-up intervals, examination items and stepped intervention strategies proposed. The etiological factors contributing to post-treatment recurrence of adult dentition diastemata and corresponding preventive measures are also analyzed. This study provides clinical references for individualized multidisciplinary management of adult dentition diastemata.
Computational aesthetics, a key subfield of computer vision, seeks to simulate human aesthetic cognition and enable machines to autonomously perceive and evaluate visual beauty. While it has found increasing application in fields such as plastic surgery and medical cosmetology, its application in the field of smile aesthetics remains limited. Currently, methods for assessing smile aesthetics rely predominantly on subjective evaluation and limited objective measurements, lacking a systematic framework that integrates multi-dimensional aesthetic features with weighted significance. This review outlines the foundational principles of computational aesthetics and surveys its current applications in medical aesthetics, with a focus on its potential application in smile aesthetics. The aim is to provide a reference for developing the next generation of assessment systems for smile aesthetics.
Oral esthetic reconstruction has evolved into a comprehensive treatment integrating functional restoration with individualized esthetics, in which multidisciplinary collaboration has become essential to the success of complex cases. However, current multidisciplinary practice still suffers from inconsistent objectives, inadequate communication, and poor coordination among disciplines, all of which compromise treatment efficiency and outcomes. This article examines six key esthetic parameters in oral esthetic reconstruction and drawing on digital technologies, systematically elaborates the techniques for transferring these parameters across disciplines. Building on this foundation, it further proposes a digital collaborative workflow centered on the "begin with the end in mind" principle, using a unified virtual patient as the carrier and forming a closed loop through backward planning and rescanning verification. Through the accurate transfer of esthetic parameters and the standardized coordination of the workflow, the challenges of communication and coordination in multidisciplinary collaboration can be effectively addressed, thereby enhancing the predictability and precision of treatment. This article aims to provide a practical reference for clinical practice and to promote the standardized and precise development of oral esthetic reconstruction.
Objective: To optimize the indirect digital transfer workflow utilizing an anatomical facebow, this study proposed a modified digital transfer table (MDTT) method based on the counterweight plate structure and magnetic embedding chimeric design of a magnetic suction transfer table. Furthermore, this study evaluated the accuracy of this method in transferring the craniomaxillary relationship, providing theoretical basis and technical support for its clinical application. Methods: A total of 28 volunteers and patients (11 males, 17 females; aged 18-29 years), including student volunteers and partially edentulous patients, were retrospectively enrolled from the Department of Implantology,School and Hospital of Stomatological Fujian Medical University between July 2024 and June 2026. For each subject, the collected data included maxillary dentition plaster models of all subjects, maxillary dentition digital models obtained by scanning plaster models, craniomaxillary positional relationship data of conventional plaster-fixed transfer table-occlusal fork and magnetically fitted transfer table-occlusal fork acquired via anatomical facebow, and craniofacial cone-beam CT (CBCT) data. The maxillary dentition models with craniomaxillary spatial information were transferred to a virtual articulator through two different workflows: the conventional anatomical facebow-based indirect digital transfer method (AFB group) and the novel MDTT method (MDTT group). Seven dental cusp landmark points were marked and matched via grid registration, including the mesiobuccal cusps of bilateral maxillary first molars, the tips of bilateral maxillary canines, the distoincisal angles of bilateral maxillary central incisors, and the midpoint of the line connecting the mesioincisal angles of bilateral maxillary central incisors. Taking the three-dimensional craniomaxillary relationship reconstructed by CBCT as the gold standard, the deviations of occlusal plane angle, three-dimensional root mean square error (RMSE) of overall dentition position, three-dimensional linear RMSE of landmark points, and three-dimensional axial deviation of each landmark were calculated in both AFB and MDTT groups to evaluate the transfer trueness. For precision assessment, pairwise registration and comparison were performed based on three repeated MDTT transfer operations, and the corresponding RMSE values and intraclass correlation coefficient (ICC) were calculated. Results: Compared to the reference standard, the MDTT group exhibited a significantly smaller occlusal plane angular deviation (1.62°±1.04°) than the AFB group (1.83°±1.07°), with a statistically significant difference (t=1.00, P=0.016). No statistically significant differences were observed in the three-dimensional dentition positional RMSE values or the three-dimensional axial deviations of the dentition between the two groups. Analysis of cusp landmark deviations revealed a statistically significant intergroup difference at the 26 site; the deviation in the MDTT group [(5.03±1.89) mm] was significantly greater than that in the AFB group [(4.84±1.70) mm] (t=-2.91, P=0.007 08) (P<0.007 14). Precision analysis indicated an ICC of 0.79 for the RMSE (P=0.599). Conclusions: designed in this study can successfully achieve spatial mapping of maxillary dentition digital models onto a virtual articulator with clinically acceptable accuracy.
Objective: To investigate the effect and mechanism of mechanical stimulation on the proliferation, migration, and osteogenic differentiation of periodontal ligament cells (PDLC) under inflammatory microenvironment by regulating mitochondrial homeostasis. Methods: An inflammatory cell model was established by treating PDLC with tumor necrosis factor-α (TNF-α, 10 ng/ml) combined with interleukin-1β (IL-1β, 5 ng/ml) for 12 h. Normal and inflamed cells were exposed to pressures of 0, 60, 120 and 180 kPa using a multi-functional pressure loading system. The expression of the osteogenic transcription factor Osterix (OSX) was detected by Western blotting and real-time fluorescence quantitative PCR to identify the most inhibitory pressure condition. PDLC were divided into control, pressure, inflammation, and inflammation+pressure groups. The mitochondrial fission inhibitor Mdivi-1 was used for intervention. The following parameters were measured: apoptosis rate by flow cytometry; indicators of mitochondrial homeostasis by fluorescence staining; and the expression of runt-related transcription factor 2 (RUNX2), OSX, collagen type I (COL-Ⅰ), interleukin-6 (IL-6), dynamin-related protein 1 (DRP1), mitofusin 1/2(MFN1/2), PTEN-induced putative kinase 1 (PINK1) and Parkin by Western blotting. Results: Under inflammatory conditions, the 180 kPa pressure group showed the most significant reduction in the relative protein and mRNA expression levels of OSX (t=8.34, P<0.05; t=4.91, P<0.05), whereas no significant differences were observed under other pressure conditions.Therefore, 180 kPa was used for the subsequent experiments. Compared with the control group, the pressure group showed no significant changes in mitochondrial homeostasis parameters. Compared with the inflammation group, the inflammation+pressure group showed disruption of mitochondrial homeostasis, and significantly elevated expression of DRP1, PINK1, and Parkin (t=3.21,P<0.05,t=2.84,P<0.05;t=3.70, P<0.05), and significantly decreased expression of MFN1 and MFN2(t=3.50,P<0.05;t=3.68,P<0.05) After Mdivi-1 treatment, the migration rate (at 3, 6, and 12 h) and proliferation rate of PDLC were significantly increased (migration: t=6.52, P<0.05;t=5.97, t=10.07, P<0.05; proliferation: t=4.73, P<0.05), and the apoptosis rate was significantly decreased (t=4.53, P<0.05). Moreover, the protein expression levels of RUNX2, OSX, and COLI were significantly increased (t=6.11, P<0.05;t=4.97, t=3.22, P<0.05), while the protein expression level of IL-6 was significantly decreased (t=3.98, P<0.05). Conclusions: Mechanical stimulation can inhibit the migration, proliferation and osteogenic differentiation of inflammatory periodontal ligament cells by disrupting mitochondrial homeostasis.
To describe an available technique for maxillary midline diastema (MMD) closure with direct composite resin restorations using modified matrix technique, determine its clinical operational procedures and feasibility, and assess its short-term clinical outcome. Eight patients who visited Department of Prosthodontics, School & Hospital of Stomatology, Wuhan University from January to April 2024 due to MMD, choosing direct composite resin restoration, were included in this study and treated using modified matrix technique. Esthetic, functional, and biological properties of sixteen restorations were evaluated according to the World Dental Federation (FDI) criteria after 12-month follow-up. The symmetry of central incisors was achieved perfectly with a correct maxillary midline in all cases. All restorations achieved a good emergence profile, a proximal contour, and a tight proximal contact. All restorations were evaluated as clinically excellent or good after a 12-month follow-up according to FDI criteria. Slight disharmony in the color match and translucency of restorations was observed in a case with a 3-mm diastema. Direct composite resin restoration with modified matrix technique presented satisfying short-term clinical outcome for MMD closure, and it is efficient in the rapid establishment of a good emergence profile and proximal contour with a correct maxillary midline. Nonetheless, large-sample, long-term follow-up prospective randomized controlled trials are required to furnish evidence for the superiority of this technique.
The long-term success of implant therapy in the anterior esthetic zone depends not only on osseointegration and implant survival, but also, and more critically, on the sustained stability of peri-implant soft-tissue architecture and esthetic outcomes. Autogenous connective tissue grafting (CTG) currently has the strongest evidence base and offers a high degree of predictability for soft-tissue augmentation. It can effectively increase peri-implant mucosal thickness, improve soft-tissue conditions at sites with a thin gingival phenotype, preserve buccal contour volume, and stabilize the peri-implant mucosal margin. However, its clinical benefits are primarily confined to soft-tissue dimensions and should not be indiscriminately interpreted as providing universal protection against peri-implant marginal bone loss. Moreover, improvements in all esthetic outcome measures cannot be assumed to occur concurrently. Soft-tissue substitutes, particularly collagen matrices, avoid donor-site morbidity and therefore represent clinically valuable alternatives for cases with low-to-moderate esthetic risk and limited soft-tissue deficiencies. Nevertheless, at high-risk sites characterized by a thin gingival phenotype, a high smile line, pronounced buccal contour collapse, or planned immediate implant placement, CTG remains difficult to replace because of its superior augmentation capacity and long-term stability. Clinical decision-making should be guided by a systematic risk assessment that integrates local hard-and soft-tissue conditions, the three-dimensional position of the implant, the transmucosal contour of the prosthetic restoration, and the patient's esthetic expectations. Precise selection of the timing of augmentation, together with the appropriate surgical technique and grafting material, is essential for developing an individualized treatment strategy that balances clinical effectiveness with minimal invasiveness.
上颌前牙区根尖周囊肿伴广泛骨缺损时，常需手术联合种植修复。该区域上牙槽前动脉变异虽罕见，术中损伤却可引发严重出血。本文报道1例前牙根折合并巨大囊肿，术前经锥形束CT识别到血管异常，数字化设计种植方案；术中骨粉填塞止血，同期完成囊肿摘除与引导性骨再生术及种植；术后使用动态加压软组织塑形技术优化美学效果，以期为复杂病例的术前评估、术中止血及美学重建提供参考。
Light-curing parameters are critical determinants of the degree of monomer conversion, mechanical properties, and color stability in composite resins. Currently, light-curing technology is evolving toward multi-mode, multi-peak wavelength, and intelligent programmed irradiation, while the photoinitiator systems of resins are transitioning from traditional camphorquinone/amine to novel amine-free systems, resulting in significantly varied responses of different materials to curing parameters. This review summarizes the comprehensive effects of light-curing parameters on the polymerization performance and long-term stability of composite resins, with a focus on the applicable boundaries of the exposure reciprocity law (ERL), the differentiated responses of various photoinitiator systems, and the potential correlation between radiant energy and color stability, aiming to provide evidence-based guidance for the precise matching of clinical light-curing protocols.
Objective: To analyze the level and trend of oral cancer mortality in China from 2004 to 2021. Methods: Mortality data were derived from the national mortality surveillance dataset of China's Disease Surveillance Points System (2004-2021) released by the Chinese Center for Disease Control and Prevention. Age-standardized mortality rates (ASMR) were calculated using the 2010 Chinese standard population. Joinpoint analysis, age-period-cohort (APC) analysis, and decomposition analysis were employed to examine the oral cancer mortality rates across different years and among populations with varying demographic characteristics. Results: From 2004 to 2021, the age-standardized mortality rate (ASMR) of oral cancer in China exhibited a significant downward trend (EAPC=-0.70, P=0.001). This decline was pronounced in urban areas (EAPC=-1.44, P<0.001), whereas rural areas showed a stable trend (EAPC=-0.24, P=0.27). The age effect indicated that mortality risk increased with age in both urban and rural populations. The period effect revealed a decreasing trend in period-specific relative risk (RR) for urban residents. The cohort effect demonstrated that more recent birth cohorts in urban areas had progressively lower mortality risk. Decomposition analysis identified population growth as the primary driver of oral cancer deaths, followed by population aging, in both urban and rural areas. Conclusions: From 2004 to 2021, the overall ASMR of oral cancer in China declined significantly, with notable disparities across urban-rural, gender, and age groups. In urban areas, both period and cohort effects showed favorable trends, with mortality risk decreasing over time and across successive birth cohorts.
Defective proliferation of Hertwig's epithelial root sheath can lead to developmental root anomalies, classically represented as taurodontism and C-shaped canals found in fused roots. While taurodontism is primarily caused by a temporal delay in the proliferation of Hertwig's epithelial root sheath epithelial flaps , the formation of C-shaped canals originates from a spatial insufficiency in their proliferation. Clinicians' understanding of C-shaped canals is often limited to the "C"-shaped orifice pattern on the pulp chamber floor, lacking a systematic appreciation of their complex three-dimensional anatomy and the associated clinical challenges. This deficiency can easily lead to iatrogenic complications and even treatment failure. This paper focuses on the etiology of C-shaped canals and their clinical implications. From the developmental perspective, it elucidates the formation mechanism of C-shaped canals, comprehensively reviews the evolution of their classification systems and current research status, and provides an in-depth analysis of the difficulties encountered in key treatment stages, including diagnosis and classification, canal preparation, obturation, and coronal restoration. Corresponding strategies are proposed to help clinicians establish a three-dimensional understanding of C-shaped canals and enhance their diagnostic and therapeutic capabilities.
本文报道1例改良隧道技术用于前牙美学区连续缺失即刻种植即刻修复的临床治疗过程，介绍改良隧道技术的具体操作步骤、技术要点、治疗效果以及术后3年随访情况，改良隧道技术可改善美学区连续缺失即刻种植软组织轮廓塌陷的问题，分享病例治疗过程中积累的经验，以期为临床提供参考。
