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 study the durability of the anti-demineralization effects of fluoride varnish after being applied to dental root surfaces. METHODS: Coronal and radicular dentin samples were prepared from extracted human teeth. Duraphat^® (DP) was applied to the dentine surfaces to form a protective film. The film-dentin interfaces were observed by scanning electron microscopy (SEM) and the fluoride element was analyzed with energy dispersive spectrometer (EDS). Thus, the differences between applying DP on crowns and roots were compared. Radicular dentin samples were prepared and randomly divi-ded into four groups: (1) Blank: DP was not applied, and demineralized in acetic acid (pH 4.5) for 4 days; (2) Blank+aging: DP was not applied, the samples were put into deionized water for 14 days at room temperature, and then demineralized in acetic acid (pH 4.5) for 4 days; (3) DP: DP was applied and demineralized in acetic acid (pH 4.5) for 4 days; (4) DP+aging: DP was applied, the samples were put into deionized water for 14 days at room temperature, and then demineralized in acetic acid (pH 4.5) for 4 days. Finally, SEM observation and EDS analysis of fluoride content were performed on film-dentin interfaces to evaluate the degree of demineralization, the morphology of DP film, and the penetration of fluorine. RESULTS: The immediate penetration depth of fluoride element from DP was deeper in the coronal dentin than that in radicular dentin. The samples in the blank and blank+aging groups demine-ralized significantly after acid etching. The DP group did not undergo demineralization, and the fluorine element penetrated to (76.00±8.94) μm below the interfaces. The structure of the protective film in the DP+aging group was damaged, but the underneath dentin did not undergo demineralization. The fluorine element still remained at a depth of (5.00±3.53) μm below the interfaces. CONCLUSION DP has an anti-demineralization effect on the root surface, and this effect can still be exerted for a period of time after losing the structure of protective film. It has the ability to prevent root caries and a certain durability.
Humans ; Tooth Root/drug effects* ; Fluorides, Topical/pharmacology* ; Tooth Demineralization/prevention & control* ; Dentin/drug effects* ; Fluorides ; In Vitro Techniques ; Cariostatic Agents/pharmacology*

OBJECTIVE: To investigate the clinical application effect of the along-axis extraction method in the extraction of impacted mandibular third molars (IMTM) and to compare the biomechanical characteristics of different root extraction techniques through three-dimensional finite element analysis. METHODS: A total of 68 patients requiring IMTM extraction were enrolled and randomly divided into two groups: the experimental group underwent the along-axis extraction method, while the control group underwent the traditional buccal bone removal and root extraction method. The duration of the procedure, intraoperative and postoperative complications were recorded. Three-dimensional finite element analysis further revealed the stress distribution in the tooth root, jawbone, periodontal ligament, and mandibular canal during different root extraction methods. RESULTS: The duration of root extraction, pain score and swelling on the first postoperative day in the control group were (7.87±3.90) min, 4.62±1.90 and (11.37±5.12) mm, respectively, which were significantly higher than those in the experimental group [(5.74±2.37) min, 3.87±1.19 and (7.22±3.39) mm, respectively]. The root fracture rate and lingual bone plate fracture rate in the control group were significantly higher than those in the experimental group (P < 0.05). The results of finite element analysis showed that the control group ' s lingual al-veolar bone had the higher peak equivalent stress, and lingual bone plate fracture was prone to occur. The periodontal ligament of the experimental group had the higher equivalent stress value, making it more likely to rip and more likely to cause root displacement. When subjected to force, the experimental group' s instantaneous root displacement was higher, but the control group ' s root displacement was more pronounced in the lingual direction. CONCLUSION This study suggests that the along-axis extraction me-thod can not only effectively shorten the operative time but also reduce postoperative complications after extraction of impacted mandibular third molars, and enhance the safety of the operation and the patient' s comfort. Three-dimensional finite element analysis shows the biomechanical characteristics of various root extraction techniques visually, serves as a valuable guide for choosing and refining clinical surgical techniques, and confirms that extracting a tooth' s root along its long axis yields better clinical results.
Humans ; Finite Element Analysis ; Tooth, Impacted/surgery* ; Tooth Extraction/methods* ; Molar, Third/surgery* ; Mandible/surgery* ; Imaging, Three-Dimensional ; Female ; Adult ; Biomechanical Phenomena ; Male ; Tooth Root/surgery* ; Young Adult ; Adolescent

Apical microsurgery is accurate and minimally invasive, produces few complications, and has a success rate of more than 90%. However, due to the lack of awareness and understanding of apical microsurgery by dental general practitioners and even endodontists, many clinical problems remain to be overcome. The consensus has gathered well-known domestic experts to hold a series of special discussions and reached the consensus. This document specifies the indications, contraindications, preoperative preparations, operational procedures, complication prevention measures, and efficacy evaluation of apical microsurgery and is applicable to dentists who perform apical microsurgery after systematic training.
Microsurgery/standards* ; Humans ; Apicoectomy ; Contraindications, Procedure ; Tooth Apex/diagnostic imaging* ; Postoperative Complications/prevention & control* ; Consensus ; Treatment Outcome

OBJECTIVES: This study aimed to evaluate the clinical application value of in-situ crown reattachment technique combined with pulpotomy in the treatment of complicated crown-root fractures in young permanent anterior teeth. METHODS: A prospective study was conducted on 50 children with complicated crown-root fractures in young permanent anterior teeth, who were treated at the Pediatric Dentistry Department, Hospital of Stomatology, Xi'an Jiaotong University from June 2023 to June 2024. All patients underwent in-situ crown reattachment technique combined with pulpotomy. Clinical examinations, radiographic evaluations, and subjective satisfaction surveys (using a Likert scale of 1-10) were conducted at 1, 6, and 12 months postoperatively. Data were analyzed using SPSS 23.0. RESULTS: The loss-to-follow-up rate was 12% (6/50), with 44 cases completing the 12 months of evaluation. The clinical success rate was 93.18% (41/44), and the radiographic success rate was 97.73% (43/44). The subjective satisfaction scores showed a significant improvement in masticatory function from 7.03±0.52 at 1 month to 8.07±0.92 at 12 months postoperatively (P<0.05), whereas the scores for aesthetics, comfort, and quality-of-life impact showed no statistically significant differences (P>0.05). CONCLUSIONS In-situ crown reattachment technique combined with pulpotomy effectively treats complicated crown-root fractures in young permanent anterior teeth, demonstrating a high short-term clinical success rate, significantly improved masticatory function, and minimally invasive preservation of pulp vitality and root development potential. This technique provides an optimized treatment option for dental trauma in children, although its long-term efficacy requires further validation.
Humans ; Pulpotomy ; Tooth Fractures/surgery* ; Child ; Prospective Studies ; Male ; Female ; Tooth Root/injuries* ; Tooth Crown/injuries* ; Treatment Outcome ; Incisor/injuries* ; Child, Preschool

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

Dental trauma is one of the relatively common emergencies in clinical dental practice, with a high incidence rate, and the maxillary central incisors are the most frequently affected. This article reports a case of a 17-year-old female patient who suffered traumatic complete avulsion of teeth 11 and 21, with tooth 21 lost after avulsion. The prognosis for replantation was poor due to the absence of the buccal alveolar bone wall of tooth 11. Therefore, tooth 11 was treated with extracorporeal root canal therapy and then replanted into the alveolar socket of tooth 21, which had better conditions, followed by elastic splint fixation. After 20 months of follow-up observation, the affected tooth maintained a stable functional position, with no periapical inflammation or ankylosis observed. Subsequently, delayed implant restoration at the site of tooth 11 was performed, ultimately achieving a favorable treatment outcome. This case may provide new insights and references for future clinical practices in tooth replantation.
Humans ; Female ; Tooth Replantation/methods* ; Incisor/injuries* ; Adolescent ; Tooth Avulsion/therapy* ; Maxilla ; Root Canal Therapy

The accidental displacement of tooth roots into the mandibular canal is a serious complication during tooth extractions in oral and maxillofacial surgery, often resulting in direct damage to the structural and functional integrity of the inferior alveolar neurovascular bundle (IANB). This article reviews the anatomical features of the mandibular canal, the IANB, and adjacent tooth roots; identifies high-risk factors and anatomically vulnerable sites for root displacement; and outlines the clinical manifestations and radiographic characteristics of intraoperative root intrusion into the mandibular canal. Furthermore, management principles, surgical approaches and techniques, inferior alveolar nerve injury treatment, and prognostic considerations are discussed. The aim of this review is to provide a comprehensive clinical reference for improving surgical outcomes, and reducing postoperative complications.
Humans ; Tooth Extraction/adverse effects* ; Mandible/surgery* ; Tooth Root ; Mandibular Nerve/anatomy & histology* ; Postoperative Complications/prevention & control* ; Intraoperative Complications ; Mandibular Nerve Injuries/etiology*

Dental trauma is a common oral condition in children. For single-type trauma to young permanent teeth, timely treatment often results in a high survival rate for both the teeth and the pulp. However, in cases of complex dental trauma or when supernumerary teeth are impacted near the apex of the injured tooth, the prognosis is less predictable. This article reports a case of root fracture in an immature maxillary permanent central incisor combined with impacted supernumerary tooth in the apical region. After supernumerary tooth extraction and pulp revascularization therapy, the case demonstrated a good treatment outcome over a nearly 10-year follow-up period.
Child ; Humans ; Incisor/injuries* ; Maxilla ; Tooth Extraction ; Tooth Fractures/complications* ; Tooth Root/injuries* ; Tooth, Impacted/surgery* ; Tooth, Supernumerary/surgery*

OBJECTIVE: To investigate the clinical and radiographic outcomes of 3 years after partial pulpotomy with iRoot BP Plus in immature permanent teeth with complex crown fracture and to provide refe-rence for the clinical application. METHODS: The study was prospectively designed and 104 immature permanent teeth with complex crown fracture were randomly allocated into two groups (n=52). The experiment group received iRoot BP Plus as the pulp capping agent while the control group received calcium hydroxide as the pulp capping agent. After partial pulpotomy, all teeth were clinically and radiographically assessed at the end of 1, 3, 6, 12, 18, 24, 30, and 36 months. The success rate in the two groups was evaluated to see if there was significant difference. The root canal wall thickness in the treated teeth was compared both between the groups and within the groups with those of the corresponding healthy teeth on the opposite side, in the same patient. RESULTS: Excluding those lost to follow-up, there were 44 teeth in calcium hydroxide group (8 teeth accounting for 15.4% were lost to follow up) and 45 teeth in iRoot BP Plus group (7 teeth accounting for 13.5% were lost to follow up) in the end. There was no intergroup difference in the success rate between calcium hydroxide group and iRoot BP Plus group (per-protocol analysis: 80% vs. 87%; intent-to-treat analysis: 67% vs. 75%). The non-inferiority margin was -10%. The 95% confidence interval of the difference in success rate was -8% to 22%. There was no significant difference in root development between the experimental teeth and contralateral control teeth. The thickness of upper 1/3 root canal in the iRoot BP Plus group was thinner than that in the CH group [(1.82±0.21) mm vs. (1.91±0.20) mm, P=0.047]. CONCLUSION iRoot BP Plus used in pulpotomy can effectively preserve the living pulp and promote the development of root in the young permanent teeth with complex crown fracture.
Humans ; Tooth Fractures ; Calcium Hydroxide/therapeutic use* ; Female ; Male ; Child ; Pulp Capping and Pulpectomy Agents ; Pulpotomy/methods* ; Prospective Studies ; Dental Pulp Capping/methods* ; Adolescent ; Dentition, Permanent ; Drug Combinations ; Tooth Crown/injuries* ; Root Canal Filling Materials ; Silicones