Objective To investigate the effects of diode laser on the bactericidal effect of Enterococcus faecalis in root canal, the external surface temperature of root canal outer wall and the morphology of dentin tubules under different irradiation modes, power, time and days, and to find the appropriate clinical operation parameters and techniques. Methods The single tube permanent tooth roots with completed root tip development were selected and divided into continuous mode group and chopped mode group according to the irradiation method. The two groups were irradiated for 10, 20 and 30 s with power of 1.5, 2.0 and 3.0 W respectively, and were continuously irradiated for 3 d. The temperature of the outer wall of the root canal was measured in each group during the first day of irradiation, and the colonies of Enterococcus faecalis were counted after daily irradiation. After 3 days of irradiation, the dentin tubule morphology of the inner wall of the root canal was observed under scanning electron microscopy, and the opening rate and opening diameter of the dentin tubule were calculated. Results ①With the increase of power and the extension of time, the bactericidal rate increased; the external surface temperature of root canal wall increased, and the dentin tubules gradually melted from opening; the opening diameter gradually shrank, and the opening rate gradually decreased, until they were completely fused and closed. In addition, the above trend was more obvious in the continuous mode group than in the chopped mode group under the same parameter. ②There was a preservation point of bactericidal rate, and there was no significant difference between 2.0 W-30 s, 3.0 W-20 s and 3.0 W-30 s under two modes on the second day of irradiation (P>0.05). ③The safe temperature limit of the outer surface of the root canal wall (10 ℃) was reached at 1.5 W-30 s, 2.0 W-20 s, 3.0 W-10 s under continuous mode and 2.0 W-30 s under chopped mode. Conclusion Diode laser continuous irradiation of root canal 1.5 W-30 s or chopped irradiation of 2.0 W-30 s for 2 consecutive days can achieve excellent bactericidal effect and no damage to the root and surrounding tissues, and can play a better role in dentin tubule closure.

Objective To assess the marginal microleakage of specimens following aging simulation of adhesive restorations for dental defects using methacryloxylethyl cetyldimethyl ammonium chloride (DMAE-CB)and nanoparticles of amorphous calcium phosphate (NACP) binder. Methods DMAE-CB and NACP were synthesized in the laboratory. Eight groups were formed by varying the mass fraction ratios of the two components in the adhesive according to previous experiments, A: binder + 3% DMAE-CB + 25% NACP, B: binder + 4% DMAE-CB + 35% NACP, C: binder + 1% DMAE-CB + 15% NACP, D: binder + 4% DMAE-CB + 15% NACP, E: binder + 1% DMAE-CB + 35% NACP, F: binder + 3% DMAE-CB, G: binder + 25% NACP, H: SBMP binder as the control group. Forty human third molars were collected and randomly divided into 8 groups to prepare standardized Class Ⅱ preparations. Subsequently, dental defect adhesive restoration specimens were made by using the 8 groups of binder, and aging simulation was performed through thermal cycling. After thermal cycling, the specimens were immersed in the dye solution. Each specimen was sectioned into 4 parts of dentin tissue slices along the gingival, proximal, and occlusal walls using a low-speed cutting machine, and the depth of dye penetration was observed under a stereomicroscope and recorded according to a unified standard for microleakage level. Finally, one randomly selected adhesive specimen from each of the 8 groups was subjected to gold sputtering and observed under scanning electron microscopy (SEM) to measure the gap width between the resin and dental tissue. Results Penetration staining showed that there were no statistically significant differences in the depth of marginal microleakage between the experimental and control groups on the gingival and occlusal walls (P>0.05). However, there was a statistically significant difference in microleakage depth between the gingival and occlusal walls (P<0.05). Scanning electron microscopy (SEM) results, after averaging particle size measurements, revealed no statistically significant differences in the gap width between the filling restorations and dental hard tissues between the experimental and control groups (P>0.05). Conclusion Dentin adhesives modified with DMAE-CB and NACP increase antibacterial and remineralization properties without affecting marginal microleakage in adhesive restorations, providing reliable theoretical support for their clinical application.

Objective To characterize the epidemiological, radiographic and clinical features of transmigrated mandibular canines by cone-beam CT (CBCT), in order to provide assistance for treatment planning. Methods Patients treated at our institution diagnosed with mandibular canines transmigration were retrospectively screened using CBCT images from June 2012 to December 2018. Clinical and radiographic parameters including location, classification, neighbouring structures, and associated anomalies were evaluated. Results Eighty-two patients with 85 transmigrated mandibular canines were enrolled, establishing a prevalence of 0.11% (82/75 021). Among these cases, 79 patients had unilateral transmigration of mandibular canines; the other 3 had bilateral transmigrations. Thirty-nine cases were male and 43 were female, with age ranging from 10 to 58. According to the Mupparapu classification, type Ⅰ (42, 49.41%) was the most prevalent followed by type Ⅱ (19, 22.35%) and type Ⅲ (15, 17.65%). Fifty-three (62.35%) crowns were located labially, and often associated with odontoma, cyst and supernumerary tooth. Seventy transmigrated canines were surgically removed while 2 cases were tried to orthodontically aligned, failed and finally extracted. Ten cases received routine monitoring. Conclusion The transmigration of mandibular canines is rarely occurring abnormality with certain clinical imaging features which can assist in clinical diagnosis and treatment planning.

Objective To investigate the influence of micro-implant length and screw angle on stress distribution and displacement of micro-implant bone interface when micro-implant was implanted in zygomatic alveolar ridge and bear a certain load, in order to provide certain theoretical basis for micro-implant selection and further optimization design in clinical practice. Methods A three-dimensional finite element model of the jaw in the zygomatic alveolar ridge region was established using ANSYS software. At the same time, 35 kinds of micro-threaded implants with length of 8, 9, 10, 11, 12 mm and angle of 30°, 45°, 60°, 75°, 90°, 105°, 120° were established. The micro-implant was simulated to be implanted in the jaw bone, and the implantation model was established. Stress analysis was performed on the bone interface of the micro-implant. Results The maximum stress of micro-implant bone interface occurred in the bone cortex. The maximum stress value of buccal cortical bone, cancellous bone and micro-implant displacement decreased with the increase of screw length. The angle of screw had little effect on the maximum stress and displacement of micro-implant-bone interface. Conclusion The screw length has an impact on stress distribution of micro-implant bone interface. The micro-implant with longer length can improve its stability in zygomatic alveolar ridge.

Objective To scan and accurately reconstruct mandible models printed via fused deposition modeling(FDM) that contain screw path information, using cone-beam CT(CBCT), to achieve the digital transfer of preoperative model screw paths. Methods CBCT scans were conducted on 12 FDM-printed mandibular models(Model1 group)intended for prebending reconstruction plates. Mimics software was employed to reconstruct scanned data into mandibular models(Model2 group) and extract digital screw path information. Model2 was then compared with original models(Model0 group) in three dimensions, evaluating reconstruction accuracy through root mean square(RMS). Reconstruction parameters were optimized to enable automatic matching of Model2 with Model0, facilitating precise digital transfer of screw paths. In clinical application, this method was utilized to produce digital short-segment drilling guides, assisting in the reduction surgery of three mandibular fracture patients. Results Model2 demonstrated automatic matching with Model0, exhibiting detailed surface characteristics and clear screw path position and orientation information. The RMS was measured at (0.32±0.09)mm. Utilization of digital segmented screw path transfer guides assisted in the satisfactory reduction surgery of three patients with comminuted mandibular fractures. Conclusion CBCT scanning of FDM-printed preoperative models accurately captures screw path position and orientation information, enabling digital transfer of screw paths and providing a novel method for precise design of digital surgical guides.

Objective To explore the aesthetic effect of adsorptive denture restoration on completely edentulous patients and the impact on masticatory function and language function. Methods A study was conducted from June 2020 to June 2023 among 85 completely edentulous patients. The patients were randomly divided into 2 groups. The routine group (n=43) underwent traditional complete denture restoration, while the observation group (n=42) underwent adsorptive denture restoration. Comparison was made between groups on the success rate of denture restoration, adaptation time, satisfaction with denture restoration, aesthetic effect, masticatory function, language function, retention stability, comfort level, the OHIP-14 scores before restoration and at 6 months after restoration, frequencies of follow-up visits and adjustments, and the incidence of complications. Results Compared with the routine group, the observation group had a significantly higher success rate of one-time denture wearing,significantly shorter adaptation time and significantly higher satisfaction with restoration, with statistically significant differences (P<0.05). After restoration, height of the lower face (Sn-Gn) increased significantly, while the midface to lower face ratio (G-Sn/Sn-Gn) and nasolabial angle (Cm-Sn-Ls) decreased significantly in both groups. The changes of Sn-Gn, G-Sn/Sn-Gn and Cm-Sn-Ls in the observation group after restoration were significantly greater(P<0.05). Bite force, masticatory efficiency, language function score, retention stability score and wearing comfort level score of the observation group were significantly higher (P<0.05). After restoration, the scores for physiological function, psychological function and activities of daily living of the two groups decreased significantly. The observation group had significantly lower life quality scores (P<0.05). The frequencies of follow-up visits and adjustments and the total incidence of complications were significantly lower in observation group (P<0.05). Conclusion Compared with traditional complete denture restoration, adsorptive denture restoration can achieve more obvious aesthetic effect on completely edentulous patients, and improve the basic function of dentures more significantly. In addition, adsorptive denture restoration has characteristics of shorter adaptation time, better prognosis and lower risk of complications.

Objective To explore the feasibility of treating recurrent mandibular neuralgia with radiofrequency thermocoagulation with double needle guide, and to study the clinical value of double needle puncture for foramen ovale. Methods In this study, 40 patients with recurrent mandibular neuralgia admitted to our hospital from January 2018 to November 2023 were selected, and randomly divided into the observation group (20 cases using double-needle guide technology) and control group (20 cases using traditional single-needle guide technology). The two groups were compared before and after treatment. Results After the completion of radiofrequency thermocoagulation therapy, the overall pain-free rate of all cases was 90% according to the adjusted grading criteria, and there was a difference in the pain-free rate between the two groups(P<0.05). There was no significant difference in the number of puncture adjustment and complications between the two groups(P>0.05). The operation time of the observation group was longer than that of the control group(P<0.05), and the number of postoperative acupuncture pain cases was statistically different from that of the control group(P<0.05). After comparison of facial visual analogue scale(F-VAS), it was found that there were significant differences between the two groups(P<0.05), and there were statistical differences between the observation group and the control group(P<0.05). Conclusion Radiofrequency thermocoagulation with double-channel technique treating patients with recurrent mandibular neuralgia is, more thorough and has less complications. Although the operation time is increased, it can effectively eliminate the pain of patients. The traditional bipolar radiofrequency thermocoagulation therapy technology is easily and accurately accomplished, which is worth popularizing.

Objective To examine the effects of SSRO (sagittal split ramus osteotomy) for Class Ⅲ malocclusion treatment on pharyngeal airway space (PAS) and respiratory function during sleep. Methods The subjects were 18 patients in whom mandibular prognathism was corrected by sagittal split ramus osteotomy. Morphological changes were studied using cone beam computed tomography at 3 days before surgery and 6 months after surgery. 3D models of the craniofacial and pharyngeal airway morphology were reconstructed with a 3D image analysis system (Mimics Innovation Suite). The anteroposterior dimension, lateral width, cross-sectional area of each subject’s pharyngeal airway were measured before and after surgery. The three airway volumes and total PAS volume were measured before and after surgery. Single polysomnography (PSG) monitoring was performed using the polysomnography system 3 days before and 6 months after orthognathic surgery, respectively, and the monitoring data were recorded. Statistical analysis of the data was performed using SPSS 25.0 software package. Results SP-AP and SP-CSA decreased after operation (P<0.05). EP-AP was significantly decreased (P<0.01)and EP-CSA decreased (P<0.05). The oropharynx volume and total PAS volume were significantly decreased, and the epiglottic volume decreased (P<0.05). There were no significant changes in respiratory function during sleep. Conclusion SP-AP, SP-CSA, EP-AP, EP-CSA, the oropharynx volume, the epiglottic volume and total PAS volume were decreased significantly after surgery. There were no significant changes in respiratory function during sleep.

Objective To evaluate the practice effect of medical record writing training based on standardized patients and explore its application in prosthodontics practice. Methods Seventy-one undergraduate interns were randomly divided into two groups. At the first week of clinical practice, the test group(n=35) adopted the SP-based medical record writing training, and after the training, the students’ evaluation of the teaching effect was investigated by questionnaire. And the control group(n=36) received traditional lectured medical record writing training. One week later, the same medical record writing exam was performed in the two groups. The scores of medical record writing of different teaching model were compared, and the evaluation of the teaching effect in the test group was carried out. Results The exam score of medical record writing of the test group (88.80±4.60) was significantly higher than that of the control group (84.92±5.51), and the difference was statistically significant(P=0.002). 88.57% of the students in the test group were satisfied with the SP-based medical record writing training. The satisfaction score was 8.94. Conclusion Medical record writing training is a long-term clinical practice. SP-based medical record writing training is helpful to improve the medical record writing quality of medical students.

Bone-related diseases are a group of inflammatory diseases characterized by abnormal bone resorption and formation, with a wide variety of diseases involving age, inflammation, obesity, genetics, radiation, and other pathogenic factors. In recent years, senescent cells have become an important mechanism for age-related diseases, and their role in bone-related diseases has attracted the attention of researchers. Senescent cells are gradually being used as therapeutic targets for bone-related diseases. In this paper, we present a review of the mechanism of senescent cells in various types of bone-related diseases, which will provide new strategies for the prevention and treatment of bone diseases.

Dentition defects in upper and posterior teeth are very common. Due to the absorption of alveolar bone and the existence of maxillary sinus, implant repair of dentition defects in upper and posterior teeth is often faced with the problem of insufficient bone height. At present, the clinical methods to solve the bone deficiency of maxillary posterior teeth include maxillary sinus floor lifting, short implant, reduced restoration, cantilever beam and inclined implant and so on. The inclined implant can make full use of the bone mass in the maxillary posterior tooth area to complete the restoration, which has the advantages of simple operation and less trauma. The objective of this review is to review and discuss the research status of oblique implant technique in the repair of maxillary posterior dentition defects, and to provide some reference for the clinical application of this technique.

Lots of patients with obstructive sleep apnea(OSA)are first recognized in dental institutions. In consideration of dental characteristics, we summarize advances in the application of screening methods for adult OSA patients based on oral examination, craniofacial structure, imaging examination, medical history, clinical symptoms, manifestation, populations at risk and questionnaires. Dental practitioners can screen and identify potential OSA patients, play a better role in the multidisciplinary of OSA, and help the prevention of OSA.

Crown lengthening is one of the common periodontal surgeries for the purposes of function, aesthetic and periodontal health. In recent years, with the continuous development of minimally invasive concept, flapless crown lengthening surgery has been receiving increasing attention in clinical practice. With the help of laser, piezosurgery and other tools, flapless crown lengthening surgery is used to remove alveolar bone through gingival sulcus without open-flap approach and suture. This minimally invasive flapless approach can avoid direct exposure of alveolar bone, and has the advantages of less bleeding, less trauma, fast healing, simple operation and high patients’ comfort. The review demonstrates surgical methods, indication selection and clinical application results of flapless crown lengthening, aiming at providing reference for clinicians to carry out this novel technique.

Osteoblasts are the main functional cells of bone formation, and their adhesion to the implants is the premise of biological function. However, most of the common clinical implants are inert metals, which have some problems such as poor biological activity and lack of bone induction, which are not conducive to osteoblast adhesion, so it is often necessary to modify their surface. Nano-morphology is a hot topic in recent years, which refers to the topological structure of implant surface unit and size 1-100 nm, similar to extracellular matrix in structure, with many advantages such as enhanced hydrophilicity, superior biocompatibility and antibacterial properties. However, not all nano-morphologies are conducive to osteoblast adhesion. This paper reviews the adhesion process, common nano-surface structure and surface modification of osteoblasts on nano-surface, in order to provide reference for implant surface nano-modification and clinical application.