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

Complex crown-root fractures in the esthetic zone refer to a type of dental trauma occurring in the anterior region, characterized by concurrent fractures involving both the crown and the root, with associated pulp exposure and periodontal tissue injury. These injuries consistently exhibit critical anatomical features, including a fixed palatal fracture location below the alveolar crest, compromised residual tooth structure, and frequent encroachment of the biological width. To predict treatment outcomes, a risk assessment framework based on the restoration-tooth-periodontium interface was developed. Resistance risk was evaluated by assessing the type of residual dentin ferrule and the length of the root within the alveolar bone, while periodontal risk was assessed according to gingival phenotype and alveolar bone morphology. Based on these risk dimensions and the principles of aesthetics, stability, and minimally invasive treatment, a diagnostic classification system was established to categorize fractures into three types: favorable, intervention and high-risk. Type-specific management strategies were proposed: for favorable cases, crown lengthening combined with deep margin elevation to reduce periodontal risk is recommended; for intervention cases, orthodontic extrusion or surgical extrusion is applied to simultaneously address both ferrule deficiency and biological width violation; for high-risk cases, extraction followed by implant restoration is advised due to limited root preservation value. The presented classification enables clinicians to adopt a scientific and structured approach to treatment planning for these complex crown-root fractures in the aesthetic zone.
Humans ; Tooth Fractures/therapy* ; Tooth Root/injuries* ; Risk Assessment ; Tooth Crown/injuries* ; Periodontium ; Esthetics, Dental ; Dental Restoration, Permanent/methods*

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*

Adolescence is defined as a population ranging from ten to nineteen years old. Permanent teeth in adolescents are of critical significance as they are actively involved in mastication, contribute to aesthetic appearance, play a role in pronunciation, and are integral to the growth and development of the stomatognathic system. Specifically, permanent teeth in adolescents comprise those with incomplete root development and those with complete root development but unstable gingival margin positions. However, the prevalence of permanent tooth defects among adolescents remains high, primarily due to their insufficient awareness of oral health care and poor compliance with preventive measures. Therefore, it is very important to emphasize the necessity for timely and appropriate restoration of permanent tooth defects in adolescents. Given the distinct physiological characteristics of adolescent permanent teeth compared with mature permanent teeth, interim restoration approaches are required. The field of adolescent permanent tooth restoration is an interdisciplinary area, involving both prosthodontics and pediatric dentistry. Currently, a comprehensive and standardized principle for the selection of restoration indications is lacking, which poses challenges for clinicians in making optimal treatment decisions. Therefore, this article aims to comprehensively summarize the clinical dilemmas associated with the restoration of adolescent permanent teeth, and propose a set of principles for the selection of restoration methods and materials, aiming to offer practical clinical guidelines for dentists when dealing with permanent tooth defects in adolescent patients. In particular, because of the different restoration dilemmas of anterior and posterior permanent teeth, a variety of interim restoration methods, their applicable conditions, advantages, and disadvantages are introduced respectively. Additionally, it provides an in-depth discussion of different interim restoration materials, including direct restoration materials like light-cured composite resin and dual-cured temporary crown resin, as well as indirect restoration materials such as polymeric porcelain and CAD/CAM resin-matrix ceramics. The goal of this research is to provide a foundation for the development of evidence-based restoration plans in clinical practice and to contribute to the establishment of future standards in the field of adolescent permanent tooth restoration. This will enhance the quality of dental care for adolescents and promote better oral health outcomes in this population.
Humans ; Adolescent ; Dentition, Permanent ; Dental Restoration, Permanent/methods* ; Child

Geriatric oral health care encounters significant challenges with the increase in the proportion of older individuals. Age-related changes in the dentition, muscles, and joints result in a decline in objective masticatory function, subjective restoration requirements, and acceptability among the elderly population, with individual variations influenced by systemic health. Considering functional requirements, the adaptability of stomatognathic and systemic health conditions, health economics and other factors, the authors believe that it should not be limited to the conventional "one-to-one" strategy for replacing missing teeth in geriatric prosthodontics. There is an urgent need for a precise and adaptable restoration strategy that is more suitable for older individuals. The proposal of a new concept of functional tooth loss updates the minimal restoration standards for elderly patients and establishes the theory of age-friendly functional restoration. Based on the restoration strategy of functional tooth loss, this paper proposes a new concept termed "age-friendly functional restoration of the stomatognathic system", which integrates treatment considerations including endodontics, periodontology, mucosa, muscles, temporomandibular joint, and systemic health. Efforts should be made in four areas as follows. Firstly, the "assessment of accessible function" should be enhanced by considering the interrelationship between stomatognathic and systemic health. Secondly, the "evaluation of appropriate function" is supposed to be optimised in view of subjective needs and objective evaluation of the stomatognathic system. Moreover, the "formulation of treatment plans" needs to be accomplished with the aid of assistive technologies, such as artificial intelligence, to accurately exert appropriate functional restoration. Lastly, the "management and maintenance of health" is likely to be strengthened through follow-ups, propaganda and education, and preventive healthcare, so as to improve quality of life and ultimately achieve healthy ageing among older individuals.
Humans ; Tooth Loss/therapy* ; Aged ; Stomatognathic System ; Oral Health ; Dental Care for Aged ; Dental Restoration, Permanent/methods*

The current low quality of fixed restoration margins is highly correlated with the high incidence of margin-related complications. It is also related to the unclear spatiotemporal geometric position relationship among the consensus definitions of the gingival margin (G), preparation margin (P), and restoration margin (R). This paper discusses the existing problem of the existing term "gingival margin" as a surface anatomical landmark; proposes the term "free gingival margin line" that conforms to geometry and measurement and has importance as a surface anatomical landmark; and clarifies the participants that exist in the marginal area. These participants include the P, R, and G; cementation (adhesive) layer; and gingival sulcus. Moreover, this paper discusses the various iatrogenic damages induced by entering the gingival sulcus via the P, R, and cementing (adhesive) layer. Through the discussion of the design deficiencies of the subgingival and biologically oriented preparation technique, the physiological and clinical importance of the concept of gingival sulcus/gingival sulcus fluid + supercrestal tissue attachment (biological width) = first periodontal protective barrier was analyzed. The value of preserving the physiological role of the gingival sulcus is emphasized. Furthermore, the newly defined RPG distance represents the distance between the successive P or R line and free G line and can be measured in the clinical procedure of tooth preparation. The optimal solution is 0-200 µm, that is, RPG200: the P and R are located on the free G line and the distance between these margins is less than 200 µm. This distance not only has the aesthetic effect of invisibility to the naked eye, it also has a minimal effect on the G and gingival sulcus and is convenient for doctors and patients to clean. Furthermore, in accordance with the positional relationship between the three margins and cementation (adhesive) layer, a new classification of marginal positions is proposed. This classification overcomes the problems of incomplete inclusion objects and uncontrolled risk factors in the previous classification. It also has the advantages of strong practicability, good efficiency of main control geometric quantity, and clear risk control points. The new design scheme and classification of the margi-nal position of RPG200 proposed in this paper provide a new understanding for margin design and complication prevention in the future.
Humans ; Gingiva/anatomy & histology* ; Cementation ; Dental Restoration, Permanent/methods*

Achieving precise restoration of tooth function and personalized restoration of natural tooth esthetics has always been a significant challenge in direct restorative dentistry. The traditional direct restorative techniques are limited by the subjective operations of dentists, resulting in high technical sensitivity, long operation time, and unpredictable restoration results, making it difficult to meet patients' personalized demands for restoration outcomes. An innovative flowable resin injection technique was introduced in this study. By combining digital design with personalized restoration guides, this technique achieves precise and personalized tooth restoration, thus revolutionizing the traditio-nal paradigm of direct tooth restoration. Specifically, this technique is guided by the patient's subjective aesthetic needs. It utilizes digital technology to pre-design the restoration result and creates a personalized restoration guide. During clinical operation, the dentist needs to only precisely inject the flowable resin into the guide, allowing for rapid completion of the restoration, thereby significantly reducing the operation time and improving the precision and predictability of the restoration. The perfect combination of digital design and flowable resin injection not only significantly improves the precision and predictability of direct tooth restoration but also remarkably shortens the clinical operation time and reduces the requirements for the dentist's technical level, making it widely applicable to the restoration of various tooth defects. Thus, it improves patient satisfaction and reduces the workload of dentists. This innovative restoration technique is expected to become a new productive force in future clinical direct adhesive restorations.
Humans ; Dental Restoration, Permanent/methods* ; Esthetics, Dental ; Composite Resins ; Computer-Aided Design ; Injections

OBJECTIVES: This study aims to evaluate the differences in shear bond strength, marginal adaptation, and nano-microleakage after aging among snowplow, layered filling, and lining techniques applied to the resin-bonded restoration of defective primary teeth. METHODS: In this study, 51 freshly extracted, crown-intact primary anterior teeth and 30 primary molars were collected. The experimental groups were as follows: layered filling group, lining group, and snowplow group. Experiments were performed to compare the differences in shear bond strength, marginal integrity, and silver ion nano-microleakage after aging among these groups. RESULTS: The median shear bond strength of the layered filling group, lining group, and snowplow group were 2.45, 5.72, and 9.43 MPa, respectively. The values for lining group and snowplow group were significantly higher than that for layered filling group (P<0.05). No statistically significant difference was found between lining group and snowplow group (P>0.05). The median overall margin integrity of the layered filling group, lining group, and snowplow group were 55.38%, 48.25%, and 65.63%, respectively. The difference among the three groups was not statistically significant (P>0.05). The median percentages of silver ion nano-microleakage in the layered filling group, lining group, and snowplow group were 11.71%, 9.47%, and 11.55%, respectively. The difference among the three groups was not statistically significant (P>0.05). CONCLUSIONS Applying the snowplow technique to restore defective primary teeth can improve the bond strength and margin integrity and reduce nano-microleakage.
Tooth, Deciduous ; Humans ; Dental Restoration, Permanent/methods* ; Dental Leakage ; Shear Strength ; Dental Bonding/methods* ; Molar ; Composite Resins ; Silver

This report presents a case of a 9-year-old child with a complicated crown-root fracture of the maxillary central incisor, accompanied with a root fracture. The treatment strategy was minimally invasive, focusing on vital pulp preservation, root fracture recovery, and crown restoration. The fractured crown was reattached using resin short posts to enhance retention, resulting in aesthetic and functional restoration of the anterior teeth. A 2-year follow-up revealed favorable clinical and radiographic outcomes.
Humans ; Child ; Tooth Fractures/therapy* ; Tooth Root/injuries* ; Incisor/injuries* ; Tooth Crown/injuries* ; Post and Core Technique ; Dental Restoration, Permanent/methods* ; Maxilla

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*