The post-and-core is a widely accepted method to restore endodontically treated teeth with compromised tooth structure. Currently, cast metal post-and-core systems and prefabricated fiber posts combined with composite resin cores are the most frequently options in dental clinical practice, but both also come with advantages and limitations. The development of computer-aided design/computer-aided manufacturing (CAD/CAM) custom fiber post-and-core represents one of the significant trends in the advancement of dentistry. Society of Digital Dental Industry, National Association of Health Industry and Enterprise Management organized experts to formulate Guidelines for CAD/CAM custom fiber post-and-core, standardizing the clinical operation procedures of this technology, enhancing the success rate of CAD/CAM custom fiber post-and-core, and promoting its application and development.
Computer-Aided Design ; Humans ; Post and Core Technique ; Composite Resins ; Dental Prosthesis Design

Clear aligner treatment is a novel technique in current orthodontic practice. Distinct from traditional fixed orthodontic appliances, clear aligners have different material features and biomechanical characteristics and treatment efficiencies, presenting new clinical challenges. Therefore, a comprehensive and systematic description of the key clinical aspects of clear aligner treatment is essential to enhance treatment efficacy and facilitate the advancement and wide adoption of this new technique. This expert consensus discusses case selection and grading of treatment difficulty, principle of clear aligner therapy, clinical procedures and potential complications, which are crucial to the clinical success of clear aligner treatment.
Humans ; Consensus ; Orthodontic Appliance Design ; Orthodontic Appliances, Removable ; Tooth Movement Techniques/methods* ; Malocclusion/therapy* ; Orthodontics, Corrective/instrumentation*

Digital technologies have become an integral part of complete denture restoration. With advancement in computer-aided design and computer-aided manufacturing (CAD/CAM), tools such as intraoral scanning, facial scanning, 3D printing, and numerical control machining are reshaping the workflow of complete denture restoration. Unlike conventional methods that rely heavily on clinical experience and manual techniques, digital technologies offer greater precision, predictability, and efficacy. They also streamline the process by reducing the number of patient visits and improving overall comfort. Despite these improvements, the clinical application of digital complete denture restoration still faces challenges that require further standardization. The major issues include appropriate case selection, establishing consistent digital workflows, and evaluating long-term outcomes. To address these challenges and provide clinical guidance for practitioners, this expert consensus outlines the principles, advantages, and limitations of digital complete denture technology. The aim of this review was to offer practical recommendations on indications, clinical procedures and precautions, evaluation metrics, and outcome assessment to support digital restoration of complete denture in clinical practice.
Humans ; Denture, Complete ; Computer-Aided Design ; Denture Design/methods* ; Consensus ; Printing, Three-Dimensional

OBJECTIVES: This study aims to explore the effect of improving clinical efficiency by replacing traditional impression workflow with centralized digital impression workflow. METHODS: The department of prosthodontics in Center of Stomatology, Peking University Shenzhen Hospital has improved the clinical workflow by replacing the traditional impression made by doctors using impression materials for each patient with a centralized digital impression made by one technician for all patients in the department. This cross-sectional study recorded the chairside time required for impression taking in patients undergoing single posterior zirconia full crown restoration before clinical process improvement; the time required for centralized digital impression production; the comfort level of patients; and the adjacency relationship, occlusal contact relationship, and time required for prostheses adjusting (i.e., whether centralized digital impressions would compromise the quality of pro-stheses and increase the time of prostheses adjusting). RESULTS: The average time to make a traditional impression was (9.98±1.41) min, and the average time required for each patient to make a centralized digital impression was (5.98±1.49) min, which was shorter than that to used make a traditional impression (P<0.05). Centralized digital impression made patients feel more comfortable compared with traditional impression (P<0.05). The adjacency relationship of restorations by centralized digital impression was more appropriate (P<0.05), and no significant difference in occlusal relationship was found (P>0.05). The time required for adjusting prostheses also had no significant differences (P>0.05). CONCLUSIONS Centralized digital impression can improve clinical efficiency for patients undergoing single posterior zirconia crown restoration. The time for impression taking is shorter, and patients feel more comfortable without compromising the quality of the prostheses.
Humans ; Cross-Sectional Studies ; Dental Impression Technique ; Crowns ; Zirconium ; Workflow ; Computer-Aided Design ; Time Factors ; Dental Impression Materials

OBJECTIVES: This study aimed to investigate the influence of the dimensional stability of 3D printed resin master model on the replication accuracy of implant replicas. METHODS: Ten digital impressions of patients undergoing continuous crowns or fixed bridge restoration supported by two implants were obtained, and resin models with implant replicas were 3D printed. Scanning rods were fixed on the replicas 3, 7, and 14 days after printing. The 3D, linear, and angular deviations of the scanning rods at different times were analyzed through Geomagic Wrap 2021 software. RESULTS: The position of the replicas shifted mesiolingually, in the same direction as the shrinkage of the model. From day 7 onward, the 3D, distance linear, and angular deviations of the replicas (scanning rod) significantly increased compared with those on the 3rd day (P<0.05). On the 14th day, the changes were even more pronounced, with the above deviations showing statistical significance (P<0.05) compared with those for the 3-day and 7-day groups. No statistical difference in height linear deviation was observed among the groups. CONCLUSIONS The insufficient dimensional stability of 3D printed resin models can lead to changes in the relative position and angle of the replicas, thereby affecting the accuracy of the replicas in recreating the implant's position. Complete manufacturing of prosthesis is recommended within 7 days after the model is printed.
Printing, Three-Dimensional ; Humans ; Dental Implants ; Models, Dental ; Dental Impression Technique ; Crowns

OBJECTIVES: To evaluate the accuracy of a self-developed extraoral scanning system based on four-camera stereophotogrammetric technology in the acquisition of three-dimensional positional information on dental implants and conduct a comparative study involving an intraoral scanning system. METHODS: With the use of an in vitro edentulous jaw model with implants, extraoral (experimental group) and intraoral (control group) scanning systems were employed to obtain STL (Standard Tessellation Language) datasets containing three-dimensional morphological and positional information on scan bodies. In addition, a dental model scanner was used to obtain reference data. The three-dimensional morphological, linear, and angular deviations between groups and reference data were analyzed using Geomagic Wrap 2021 software to compare trueness and precision. RESULTS: The extraoral scanning system demonstrated superior trueness in three-dimensional morphological, linear, and angular deviations compared with the intraoral scanning system, with statistically significant differences (P<0.001). The extraoral scanning system also showed a higher precision in three-dimensional morphological deviation (P<0.001). As the number of implants increased, the extraoral scanning system exhibited increased three-dimensional morphological and linear deviations (P<0.001) but maintained a stable angular deviation. The intraoral scanning system displayed significant increases in three-dimensional morphological, linear, and angular deviations with the increase in the number of implants (P<0.05). CONCLUSIONS The stereophotogrammetry-based extraoral scanning system outperforms intraoral scanning system in terms of the accuracy for multi-unit implant positioning and provides a novel approach for attaining a fully digital workflow for implant rehabilitation in edentulous jaws.
Jaw, Edentulous ; Humans ; Dental Impression Technique ; Dental Implants ; Imaging, Three-Dimensional/methods* ; Photogrammetry/methods* ; Models, Dental

Objective: To explore the effect of scanning methods on finish line trueness of the full crown preparation. Methods: The standard full crown preparation model of the right maxillary first molars was prepared by using the maxillary standard resin dentition model. The standard preparation was scanned by imetric scanner and data were used as the true value. CEREC Omnicam and 3Shape TRIOS were used to scan the standard preparation. According to the scanning methods, they were divided into parallel scanning group, occlusal wave scanning group and buccolingual wave scanning group. Each group was scanned repeatedly 6 times. The data were imported into Geomagic Studio 2013 software, and the local finish line image data of the mesial, distal, buccal and lingual regions of the full crown preparation were extracted respectively. Three-dimensional deviation analysis was performed with the reference true value, and the root- mean-square error (RMSE) was the evaluation index of scanning trueness. The statistical method was one-way ANOVA. Results: Parallel scanning group: in general, the RMSE value of complete finish lines of scanner B [(35±6) μm] was significantly lower than that of scanner A [(44±7) μm](P<0.05). After scanner A occlusal wave scanning, the RMSE values of the mesial and distal finish lines [(33±5) and (50±12) μm] were significantly lower than those of parallel scanning group (P<0.05). After buccal and lingual wave scanning, the RMSE values of local finish lines in the mesial, distal, buccal and lingual regions [(37±3), (50±6), (28±6) and (29±8) μm] were significantly lower than those in parallel scanning group [(45±9), (63±7), (38±3) and (40±3) μm] (P<0.05). No significant difference was found in the RMSE values of the mesial, distal, buccal and lingual regions of scanner B between parallel scanning group, occlusal wave scanning group and buccolingual scanning group (P>0.05). Conclusions: The scanning trueness of the full crown preparation finish line obtained by the active triangulation scanning equipment can be improved by changing the scanning method to wave scanning.
Humans ; Imaging, Three-Dimensional ; Dental Impression Technique ; Computer-Aided Design ; Dental Care ; Crowns

OBJECTIVE: To predict the learning curve of tooth preparation for all ceramic crowns of maxillary central incisors on phantom head simulators for graduate students participating in standardized dental resident training based on the modified Wright learning curve model, then to analyze and applicate the learning curve. METHODS: Twelve graduate students participating in standardized dental resident training were selected to prepare the resin maxillary central incisors on phantom head simulators for all ceramic crowns 4 times. The results of preparation were evaluated by 3 prosthetic experts with at least 10 years' experience focusing on the reduction, contour, taper, shoulder, finish line, margin placement, adjacent tooth injury, and preparation time for tooth preparation. The learning rate of tooth preparation was calculated by scores of tooth preparation of 4 times. The learning curve of tooth preparation was predicted based on the modified Wright learning curve model. According to the criteria of standardized training skill examinations for dental residents in Beijing, 80 was taken as the qualified standard score. The minimum training times for tooth preparation to satisfy the qualified standard score (80) was calculated, to analyze the characteristics of learning curve and evaluate the effectiveness of tooth preparation. RESULTS: The scores of 4 tooth preparation were 64.03±7.80, 71.40±6.13, 74.33±5.96, and 75.98±4.52, respectively. The learning rate was (106±4)%, which showed the learning curve an upward trend. There were no significant differences between the qualified standard score and the predicted scores of tooth preparation from the 5^th preparation to the 13^th preparation (P > 0.05). The predicted score of the 14^th preparation was higher than the qualified standard score (P < 0.05). CONCLUSION The trend of the learning curve of tooth preparation for all ceramic crowns of maxillary central incisors on phantom head simulators for graduate students participating in standardized dental resident training is upward, which predicts the minimum training times higher than the qualified standard score is 14 times.
Humans ; Tooth Preparation, Prosthodontic/methods* ; Incisor ; Learning Curve ; Crowns ; Tooth Preparation ; Ceramics ; Dental Porcelain ; Dental Prosthesis Design

Using digital technologies in concurrently performing missing tooth implantation and preparation of remaining teeth is a solution to reduce the number of visits and improve efficiency. This paper proposes a digital process for simultaneously implanting and preparing teeth. It integrates implant surgical guide and 3D-printed tooth preparation guide into a single guide and completes guided implant placement and precise tooth preparation. Based on "repair-oriented" virtual implant planning, the implant surgical guide can improve the efficiency and predictability of implant placement, and its linear accuracy is about 1 mm. The tooth preparation guide precisely guides tooth preparation and restoration space visualization, ensuring the quality of the tooth preparation. The two guides have different design accuracy requirements, and thus their combination improves the overall guiding accuracy requirements. The concurrent application of the two guides minimizes the clinical operation time, number of visits, and economic burden of patients.
Humans ; Surgery, Computer-Assisted ; Dental Implantation, Endosseous ; Printing, Three-Dimensional ; Technology ; Tooth Preparation ; Computer-Aided Design ; Dental Implants ; Imaging, Three-Dimensional ; Cone-Beam Computed Tomography

OBJECTIVES: The objectives of this study were to assess the quality of prosthetic prescriptions of removable partial dentures (RPDs) and to analyze the current situation of the communication and information delivery between clinicians and technicians. METHODS: All RPD prosthetic prescriptions received by a major dental laboratory in 4 weeks were involved in a quality audit, and the prescriptions were divided into three groups in accordance with the grades of clients. The filling of prosthetic prescriptions was recorded. The items in the prescriptions for audit included the general information of the patient, the general information of the clinician, the design diagram information, other detailed information, and the return date. The prescriptions were categorized into four levels on the basis of their quality by two quality inspectors who have been working for more than 10 years. RESULTS: A total of 916 prescriptions were collected and assessed. The names in the general information of the patient and the clinician were filled out best, both at the rate of 97.6% (n=894). The return date was filled out worst, only at the rate of 6.4% (n=59). Of those prescriptions, 86.8% (n=795) exhibited inadequate design diagram information. The results of the quality assessment demonstrated that 74.2% of prescriptions were assessed as noncompliant ones and failed to meet the acceptable clinical quality standard. CONCLUSIONS At present, the overall quality of RPD prosthetic prescriptions is poor. The responsibilities of clinicians and technicians are unclear, and the communication between them is not ideal.
Humans ; Denture Design ; Denture, Partial, Removable ; Prescriptions