The evolution of three-dimensional wearable display technology, from early two-dimensional images to the current stereoscopic vision, reflects the deep integration of medical engineering. By performing high-precision video capture of the surgical area, 3D head-mounted devices simulate human binocular disparity to acquire stereoscopic images with enhanced depth perception. When instrument separation occurs within the root canal, this technology enables clinicians to more accurately locate the separated instrument, clearly visualize its adaptation to the canal walls, and discern the angulation between the instrument and the curved root canal. Consequently, it significantly improves treatment precision, success rates, and operator comfort. This article reviews the clinical application of 3D head-mounted devices in the removal of separated instruments.

Instrument separation is a common complication in endodontic treatment, and its prognosis depends on multiple factors, including the periapical status and the location of the separated instrument. In teeth with vital pulp or without periapical lesions, retaining the instrument followed by careful root canal obturation generally results in a favorable prognosis. In contrast, for infected canals or those with periapical periodontitis, instrument removal and, when necessary, endodontic surgical intervention are more clinically significant. With the development of advanced techniques such as dental microscopy, ultrasonics, cone-beam computed tomography (CBCT), and artificial intelligence, the diagnosis and management of separated instruments have become increasingly precise. Nevertheless, further evidence-based research is required. This article analyzes and summarizes the existing evidence in combination with clinical experience to provide a reference for clinical decision-making.

To explore techniques for retrieving separated instruments from root canals without direct access and with complex resistance, analyze the key points, advantages, and risks of the bypass-based retrieval method, and evaluate treatment outcomes.

Cases were collected from the Department of Endodontics at Xiangya Stomatological Hospital, Central South University, between 02/2017 and 01/2025. Preoperative imaging confirmed instrument separation within the root canals, where non-sleeve or ultrasonic methods were not indicated. Instead, endodontic files were used to bypass and prepare the canals around the separated instruments for retrieval. Follow-up data were collected for at least six months postoperatively. Patient demographics, instrument location, length, material, type, root canal morphology, postoperative imaging, clinical outcomes, and follow-up data were summarized. The frequency of each variable was recorded, and relevant influencing factors and treatment outcomes were analyzed.

A total of 175 patients (175 teeth, 176 fractured instruments) were included, comprising 52 males (29.7%) and 123 females (70.3%). The oldest patient was 73 years old, while the youngest was nine years old, and the average age was 28 years. Separated instruments were made of stainless steel in 44 cases, nickel-titanium in 108 cases, and carbon steel in 24 cases with an average length of 4.1 mm and an average fragment diameter of 0.32 mm. The fragments were located in the apical third of 67.6% of cases, with 46 cases (26.1%) occurring in the blind zone. The average distance from the canal orifice was 5.6 mm. The file tip extended beyond the apical foramen in 17 cases. Moderate to severe root canal curvature (≥10°) was observed in 93.7% of cases, with an average curvature angle of 29.3°. Preoperative periapical radiolucency was observed in 151 cases (86 of which had symptoms), while 24 cases showed no periapical radiolucency (seven of which had clinical symptoms). Complete retrieval was achieved in 160 cases. Secondary separation occurred in four cases, and retrieval failed in six cases. Postoperative imaging revealed significant canal deviation in 34 cases (including three cases with deviation and perforation), while no significant morphological deviation was observed in 141 cases (80.6%). Follow-up results showed that among patients with preoperative periapical radiolucency and symptoms, 83 cases experienced symptom relief or healing after retrieval, while one case still had symptoms and periapical radiolucency after six months. Among asymptomatic patients with preoperative periapical radiolucency, two cases developed symptoms after retrieval, and two cases still had symptoms after six months, though one of these showed healing of periapical radiolucency. Among symptomatic patients without preoperative periapical radiolucency, two cases experienced symptom relief after retrieval, while three cases still had symptoms after six months, with one of these developing radiolucency. Asymptomatic patients without preoperative periapical radiolucency (17 cases) remained symptom-free after retrieval, though four cases developed symptoms after six months, with two of these showing periapical radiolucency.

The bypass technique can serve as a safe and reliable method for retrieving separated instruments from root canals with complex resistance but direct access.

Instrument separation in the apical region, particularly when the fragment extends beyond the apical foramen, often presents significant clinical challenges. Conventional retrieval techniques typically require excessive removal of radicular dentin, which may not only lead to complications such as root perforation or fracture, but also compromise the long-term prognosis of the affected tooth. However, for cases occurring during the final stages of high-quality root canal treatment, retaining the separated instrument may represent a more rational clinical approach when strict indications are met. This article reports a tooth with preoperative periapical pathology that experienced instrument separation extending beyond the apical foramen during treatment. Following comprehensive evaluation, a retention protocol was adopted. Nine years of follow-up observations confirmed the tooth's maintained functional integrity, validating the clinical efficacy and long-term sustainability of this management approach.

Endodontic instrument fracture is one of the common complications of root canal therapy and often occurs without warning. When instrument separation occurs, a small section of root canal file remains within the root canal, complicating the root canal treatment process. Isolated instrument fragments may hinder further cleaning and shaping of the root canal, potentially affecting the overall success rate of root canal treatment. This article summarizes the research on instrument separation in recent years, and discusses its causes, treatment methods and prevention methods, to provide decision-support for clinical practice.

To compare the objective brushing data recorded by the smart electric toothbrushes with the participants′ self-reported brushing behaviors, and to analyze the differences in brushing habits reflected by the two and their influencing factors.

A total of 18 169 users aged 18-45 years old who used the same smart electric toothbrushes between January and December 2024 were included as study subjects. Data on brushing behaviors (average daily brushing frequency, single brushing duration) were obtained through smart electric toothbrush recordings and participant self-reports by filling out questionnaires, and were statistically analyzed using Kappa consistency test, chi-square test, and binary logistic regression.

Among the participants, 9 864 individuals (54.3%) reported brushing habits consistent with those recorded by the smart toothbrush, while the remaining 8 305 individuals (45.7%) exhibited inconsistencies. This difference was statistically significant (κ = 0.106, P<0.001), with 92.8% (7 711/8 305) of the inconsistent group being overestimators of their subjective behavior. Among study participants who self-reported periodontal symptoms, the proportion of those who underestimated their subjective behavior was 8.1%, higher than those without periodontal symptoms (6.6%) (χ² = 6.332, P = 0.012). Binary logistic regression analysis showed that participants with periodontal symptoms were 1.224 times more likely to underestimate their brushing behavior than those without periodontal symptoms (OR = 1.224, 95% CI: 1.032 ~ 1.453, P = 0.02) .

Individuals′ perception of their brushing behavior deviates significantly from the actual situation, and individuals tend to overestimate their actual toothbrushing behavior. The occurrence of periodontal symptoms makes individuals improve the accuracy of their perception of brushing behavior. Smart electric toothbrushes can help users correct cognitive bias and improve oral health management through mechanisms such as objective data feedback.

To investigate the prevalence and dynamic changes of dental caries in primary teeth among 3- to 5-year-old children in Kashgar, Xinjiang, analyze its influencing factors, and provide a scientific basis for the prevention and control of dental caries in this region.

A random sampling method was employed to select children aged 3-5 from two kindergartens in urban and suburban areas of Kashgar City. A baseline survey was conducted in May 2021, followed by a follow-up survey one year later. Caries and oral hygiene status were assessed using the WHO diagnostic criteria for caries and the Debris Index, combining visual inspection and probing. Chi-square (χ²) tests and paired Wilcoxon signed-rank tests were used to compare differences between years and groups.

The baseline survey included 315 children aged 3-5, with a caries prevalence of 74.3% and a mean dmft of 2.51. One year later, the caries prevalence increased to 86.7% (χ² = 17.398, P<0.001), and the mean dmft rose to 2.83 (W = 12 759.0, P = 0.022). The caries prevalence significantly increased in both boys (χ² = 7.220, P = 0.007) and girls (χ² = 9.818, P = 0.002). The largest increase in caries prevalence was observed in 3-year-old children, rising from 65.8% to 83.6% (χ² = 13.796, P<0.001). The mean dmft for children aged 3-5 increased from 2.51 to 2.83 (W = 12 759.0, P = 0.022), with significant increases observed in girls (W = 1 926.0, P = 0.018), 3-year-old children (W = 1 940.5, P<0.001), and Uygur children (W = 3 633.0, P = 0.034). Additionally, the Debris Index for the 315 children increased from 4.95 to 5.43 (W = 5 479.0, P<0.001), with statistically significant changes in all subgroups except for 4-year-old children (W = 398.5, P = 0.249). The questionnaire results indicated that urban residence (χ² = 14.138, P<0.001), frequent dairy consumption (χ² = 4.700, P = 0.030), non-use of fluoride toothpaste (χ² = 4.310, P = 0.038), and lower parental oral health knowledge scores (χ² = 11.270, P<0.001) were significant influencing factors for childhood dental caries.

The prevalence of deciduous tooth caries is high among children aged 3-5 in Kashgar City. Over the course of one year, the severity of caries increased more significantly in 3-year-old children, girls, and Uygur children. Longitudinal surveys on caries incidence are of greater value and provide guidance for targeted prevention and control in key populations.

This case report describes a rare and widespread ossifying fibroma of the mandible in adolescents, secondary to significant aneurysmal bone cyst formation. Its clinical manifestations are typical (maxillofacial deformity, nerve injury), and the imaging and pathological diagnoses are clear. Through meticulous preoperative embolization and complex radical resection combined with microvascular anastomosis for free flap reconstruction, the patient achieved a good short-term therapeutic outcome.

Salivary secretory carcinoma (SSC) is a low-grade malignant tumor of the salivary gland, newly introduced in the fourth edition of the World Health Organization′s classification of head and neck tumors (2017). It is relatively rare in clinical practice, with very few reported cases involving the submandibular gland. This article reported one case of secretory carcinoma occurring in the submandibular gland and reviews related literature.

As the most prevalent congenital craniofacial developmental anomalies, non-syndromic orofacial clefts (NSOC) are complex polygenic disorders arising from the interplay of genetic susceptibility, environmental exposures, and gene-environment interactions. Genome-wide association studies (GWAS) have identified numerous single nucleotide polymorphism (SNP) associated with NSOC risk. However, individual variants exhibit limited clinical utility for risk prediction due to their modest effect sizes. The polygenic risk score (PRS) aggregates the effects of SNP to provide disease-related risk information, which has demonstrated remarkable efficacy in disease prediction across various complex disorders. However, its application to NSOC remains in its infancy. This study reviews the advancements in PRS methodologies for predicting NSOC risk and discusses the current challenges and future directions for PRS development in this field.

Cleft lip and palate (CL/P) is one of the most common craniofacial deformities. The main impact of cleft palate on patients is speech disorders, and speech therapy is the main method to solve speech disorders after cleft palate surgery. In recent years, the impact of speech therapy on the brain regions of CL/P speech disorder patients has become a concern. Current research has found that through functional magnetic resonance imaging (fMRI) examination, changes in the structure and function of the relevant brain regions of CL/P speech disorder patients have been observed. Therefore, whether speech therapy has an impact on the brain neural network of CL/P speech disorder patients has great significance for guiding clinical treatment. This article reviews the current status and progress of fMRI research on the impact of speech therapy on brain regions of patients with CL/P speech disorders.

Temporomandibular joint osteoarthrosis is a multifactorial disease with complex pathogenic mechanisms, involving synovial inflammatory response, cartilage degeneration, and condylar bone destruction. Traditional treatments for this disease, such as medication, physical therapy, and surgery, have obvious limitations. They can only relieve clinical symptoms but fail to promote tissue repair and regeneration, and there is currently no radical cure. As a biological agent, platelet-rich plasma is rich in growth factors and other components. It has shown great potential in the field of tissue regeneration and repair through promoting cell proliferation, inhibiting inflammation, and regulating the local microenvironment, and has attracted much attention in the treatment of osteoarthrosis in recent years. This article elaborates on the pathological process of temporomandibular joint osteoarthrosis, analyzes the bioactive components of platelet-rich plasma and its mechanism of action, summarizes its application research in osteoarthrosis, and analyzes the feasibility and clinical effects of its treatment for temporomandibular joint osteoarthrosis, aiming to provide a reference for in-depth research on platelet-rich plasma in this field.