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

OBJECTIVE: To compare the influence of different emergence profile of implants in mandibular molar on the peri-implant soft tissue. METHODS: Forty-four implants were divided into two equal groups by mucosal thickness, ≥2 mm (group A) or < 2 mm (group B), and were randomly included in the test group and the control group. In the control group, the patients were treated by a prosthesis with no transmucosal modifications (subgroups A1 and B1). In groups A1 and B1, the prostheses maintained the original emergence profile of the healing abutment. In the test group, the prostheses were designed based on a width-to-height ratio (W/H) of 1.3 ∶ 1 (subgroups A2 and B2). In group A2, the buccal transmucosal configuration design was slightly concave, and in group B2, the prostheses were designed with convex buccal transmucosal configuration. Assessments were made before delivery of the definitive restoration (T0), one month (T1) and 12 months (T2) after loading. The soft tissue and prosthesis information were obtained by intraoral scan and were converted to digital models. The digital models of different time were superimposed together. Buccal mucosal W/H, emergence angle (EA) and buccal mucosal margin recession (ΔGM) were measured. RESULTS: One year after loading, the buccal mucosal margin recession in the test group (groups A2 and B2) was significantly lower than that in the control group (groups A1 and B1). The ΔGM in group A2 was significantly lower than that in group A1 (P=0.033), but in groups B1 and B2, it was not significantly different. The W/H in group A2 increased significantly one month after loading, but remained stable at one year. In the A1 group, the W/H changed little from initial to one month, but increased significantly at one year after loading. The W/H in group B2 remained stable from the beginning to one year, while in group B1, it changed little one month after loading, but increased significantly by one year. CONCLUSION When the initial mucosal thickness was ≥2 mm, the slightly concave prosthesis designed based on the biological W/H significantly maintained the level of buccal mucosa. When the mucosal thickness was < 2 mm, the slightly convex prosthesis design maintained a more stable W/H over one year.
Humans ; Mandible/surgery* ; Molar/surgery* ; Male ; Female ; Adult ; Middle Aged ; Dental Prosthesis Design ; Dental Implants ; Dental Implantation, Endosseous/methods*

Immediate implant-supported fixed restoration in edentulous jaws demonstrates a success rate comparable to that of conventional implant restoration. However, this approach still presents a certain degree of technique sensitivity. In the field of immediate implant-supported fixed restoration in dentistry, a repeatable and stable jaw relation is the prerequisite for the design and fabrication of prostheses. It also reduces chairside denture placement and occlusal adjustment time and lowers the risk of occlusion-related complications. For patients with terminal dentition, the precise transfer of jaw relation following full-arch implantation serves as the fundamental basis for implant-supported occlusal reconstruction and functional restoration. This process is also a key research focus and challenge in the area of implant-supported occlusal rehabilitation. This review summarizes the procedures and methods for determining and transferring jaw relation in immediate implant-supported fixed restoration. It aims to serve as a basis for clinical decision making in implant-supported fixed restorations for terminal dentition patients.
Humans ; Dental Prosthesis, Implant-Supported ; Clinical Decision-Making ; Immediate Dental Implant Loading ; Jaw, Edentulous/surgery*

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

OBJECTIVES: This study aimed to evaluate the long-term clinical efficacy of simple taper retentive implants in the posterior dental area after immediate implantation for 5-7 years. METHODS: Selected from January 2015 to December 2017 in the Fourth Affiliated Hospital of Nanchang University dental clinic line tooth area immediately after the implant prosthesis, a total of 38 patients, 53 implants, were deep into (bone under 2 mm or higher) and the upper structure was repaired. In addition, after the completion of tracking observation of 60-90 months, the implant surrounding bone health was recorded and analyzed. RESULTS: After 5-7 years of follow-up, 1 of the 53 implants failed to fall out, and the implant retention rate was 98.1%. The amount of bone resorption in the proximal and distal margins 5-7 years after implant restoration was (0.16±0.94) mm and (-0.01±1.29) mm, respectively, and the difference in bone height between the proximal and distal margins of the implant and the immediate post-restoration period was not statistically significant (P>0.05). No statistically significant differences were found in the effects of periodontitis, implant site inflammation, and smoking on peri-implant marginal bone resorption (P>0.05). CONCLUSIONS The single taper-retained implant broadens the indications for immediate implant placement in the posterior region, and its deep sub-osseous placement (≥2 mm below the bone) avoids to a certain extent the disturbance of the implant by external stimuli and the exposure of the cervical abutment of the implant, with the good long-term stability of the marginal bone around the implant.
Humans ; Dental Implantation, Endosseous ; Dental Implants ; Immediate Dental Implant Loading ; Follow-Up Studies ; Dental Implants, Single-Tooth ; Alveolar Bone Loss/surgery* ; Treatment Outcome ; Dental Prosthesis, Implant-Supported ; Dental Restoration Failure

In the field of dental implantology, the design of interface esthetics not only affects the esthetic coutcome, but also affects the health and long-term stability of the tissue around dental implant. Dental implant, bone tissue, soft tissue, and prostheses' morphology are the four critical elements of interface esthetics. The emergence profile located at the junction of these four components is an important form of oral esthetics. With the wide application of digital technique in the field of dentistry, the shaping of emergence profile also involves the application of many kinds of digital approaches. This article intends to make a review of the application of digital technique in rehabilitation of interface esthetics to provide a reference for clinical practic.
Dental Implants ; Dental Prosthesis, Implant-Supported ; Esthetics, Dental

Recently, among the edentulous patients who undergo dental implants, the proportion of hypertensive patients remains high, which poses a greater challenge for clinicians to operate and to maintain the therapeutic effect. The present review comprehensively summarized clinical researches about the adverse effects on dental implants, outlined molecular mechanisms of the positive effects of various antihypertensive drugs on bone metabolism, and proposed that clinicians should select preventive strategies during preoperative and intraoperative procedures according to the blood pressure of patients with hypertension.
Alveolar Bone Loss ; Dental Implantation, Endosseous/methods* ; Dental Implants ; Dental Prosthesis, Implant-Supported ; Dental Restoration Failure ; Humans ; Hypertension/surgery* ; Jaw, Edentulous ; Maxilla/surgery* ; Risk Assessment

According to the fourth national oral health epidemiological survey report (2018), billions of teeth are lost or missing in China, inducing chewing dysfunction, which is necessary to build physiological function using restorations. Digital technology improves the efficiency and accuracy of oral restoration, with the application of three-dimensional scans, computer-aided design (CAD), computer-aided manufacturing (CAM), bionic material design and so on. However, the basic research and product development of digital technology in China lack international competitiveness, with related products basically relying on imports, including denture 3D design software, 3D oral printers, and digitally processed materials. To overcome these difficulties, from 2001, Yuchun Sun's team, from Peking University School and Hospital of Stomatology, developed a series of studies in artificial intelligence design and precision bionics manufacturing of complex oral prostheses. The research included artificial intelligence design technology for complex oral prostheses, 3D printing systems for oral medicine, biomimetic laminated zirconia materials and innovative application of digital prosthetics in clinical practice. The research from 2001 to 2007 was completed under the guidance of Prof. Peijun Lv and Prof. Yong Wang. Under the support of the National Natural Science Foundation of China, the National Science and Technology Support Program, National High-Tech R & D Program (863 Program) and Beijing Training Project for the Leading Talents in S & T, Yuchun Sun's team published over 200 papers in the relevant field, authorized 49 national invention patents and 1 U.S. invention patent and issued 2 national standards. It also developed 8 kinds of core technology products in digital oral prostheses and 3 kinds of clinical diagnosis and treatment programs, which significantly improved the design efficiency of complex oral prostheses, the fabrication accuracy of metal prostheses and the bionic performance of ceramic materials. Compared with similar international technologies, the program doubled the efficiency of bionic design and manufacturing accuracy and reduced the difficulty of diagnosis and cost of treatment and application by 50%, with the key indicators of those products reaching the international leading level. This program not only helped to realize precision, intelligence and efficiency during prostheses but also provided functional and aesthetic matches for patients after prostheses. The program was rewarded with the First Technical Innovation Prize of the Beijing Science and Technology Awards (2020), Gold Medal of Medical Research Group in the First Medical Science and Technology Innovation Competition of National Health Commission of the People's Republic of China (2020) and Best Creative Award in the First Translational Medical Innovation Competition of Capital (2017). This paper is a review of the current situation of artificial intelligence design and precision bionics manufacturing of complex oral prosthesis.
Artificial Intelligence ; Bionics ; Computer-Aided Design ; Dental Prosthesis Design ; Humans ; Printing, Three-Dimensional ; Prostheses and Implants

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.
Child ; Computer-Aided Design ; Crowns ; Dental Prosthesis Design ; Female ; Humans ; Male ; Software ; Tooth Crown ; Tooth, Deciduous

Based on evidence-based clinical and material researches, the Society of Prosthodontics, Chinese Stomatological Association organized a panel of experts to write a recommended application guideline via in-depth discussion and literature reviewing. This guideline formulates the standardized operation procedures for the clinical usage of chairside computer aided design and computer aided manufacturing (CAD/CAM) rehabilitation with resin-ceramic composites, aiming at guiding and specifying this clinical technique. This guideline will help to improve the quality, the clinical efficacy, and the long-term success rate of chairside CAD/CAM rehabilitation with resin-ceramic composites via standardizing this restoration technique. At the same time, this guideline will contribute to the clinical promotion of this technique.
Ceramics ; Composite Resins ; Computer-Aided Design ; Dental Prosthesis Design ; Prosthodontics