Oral potentially malignant disorders (OPMDs) are a group of mucosal diseases characterized by abnormal changes of the oral mucosa with potential risk of malignant transformation. Clinical treatment aims to alleviate symptoms, eliminate lesions, and prevent cancer development. Conventional methods, such as surgery and pharmacotherapy, are associated with limitations including invasiveness, significant side effects, and poor patient compliance. Photodynamic therapy (PDT), as a minimally invasive and precisely targeted treatment modality, has demonstrated promising outcomes in the management of OPMDs. This review summarizes recent advances in the clinical application of PDT for major OPMD subtypes, including oral leukoplakia, oral lichen planus, and oral submucous fibrosis. It evaluates the efficacy and safety of PDT, discusses current challenges, and suggests future directions, with the goal of providing a reference for standardizing PDT protocols and guiding further research.

With the widespread application of digital technology in the field of stomatology, digital intraoral scanning has become a crucial tool in clinical dental diagnosis and treatment. However, the accuracy of intraoral scanning is influenced by various factors, among which the use of auxiliary scanning devices plays a critical role in determining its precision. This review systematically reviews the impact of different auxiliary scanning techniques on the accuracy of digital intraoral scanning, with a focus on the application effectiveness of key techniques including scanning-aid material, artificial landmarks, geometric auxiliary devices, and modified scanbody. Through systematic analysis of existing literature, the review thoroughly examines the strengths and limitations of several auxiliary scanning techniques, and furthermore, provides insights into their future development trends. The findings aim to offer theoretical foundations and practical guidance for enhancing the accuracy and clinical value of digital intraoral scanning.

Autogenous dentin matrix (ADM), derived from extracted teeth of patients, has emerged as a novel natural bone substitute with excellent biocompatibility and osteogenic potential. In recent years, ADM has attracted increasing attention in the field of oral implantology, particularly for alveolar ridge preservation (ARP). ADM retains the mineralized structure and biological activity of natural dentin, providing osteoconductive and osteoinductive properties that effectively promote new bone formation and maintain alveolar bone volume after tooth extraction. This review summarizes the material characteristics and osteogenic mechanisms of ADM, outlines its current clinical applications in ARP, and compares its performance with conventional bone graft materials. Furthermore, it discusses existing challenges such as the lack of standardized preparation protocols and limited long-term clinical evidence. With ongoing optimization of processing techniques and advances in clinical research, ADM is expected to achieve broader clinical applications in oral implantology and bone regeneration.

Objective: To investigate the impact of amelotin knockout (Amtn^-/-) on the function of the junctional epithelium barrier (JEB). Methods: Mandibular specimens from littermate Amtn^-/- and wild-type (WT) mice were compared. Periodontal tissue morphology and enamel mineralization were analyzed using scanning electron microscopy (SEM), hematoxylin-eosin (HE) staining, immunohistochemistry (IHC), and micro-computed tomography (micro-CT). Results: Three-month-old Amtn^-/- mice exhibited alveolar bone resorption, furcation exposure, disorganized periodontal fibers, junctional epithelium (JE) disintegration with apical migration, and age-dependent exacerbation. One-month-old Amtn^-/- mice showed severe molar enamel wear, residual matrix proteins in ameloblasts, and lack of epithelial coverage in unerupted molars (Amtn^-/- mice). For Amtn^-/- mice, IHC revealed downregulated laminin gamma-2 (LAMC2) expression in the JE basement membrane but upregulated within JE; matrix metalloproteinase-9 (MMP-9) expression was enhanced in both basement membrane and JE interior. Conclusion: Deletion of the Amtn gene can lead to poor enamel mineralization and destruction of JE adhesion, which may be related to the abnormal expression of LAMC2 and MMP-9.

Objective: To investigate whether exosomes derived from porphyromonas gingivalis-lipopolysaccharide (Pg-LPS)-activated macrophages promote osteoclasts differentiation via the p38 mitogen-activated protein kinase (p38 MAPK)/matrix metalloprotein 9 (MMP-9) signaling pathway. Methods: A mouse periodontitis model was established by ligature, and alveolar bone loss was assessed using micro-computed tomography (Micro-CT), quantitative reverse transcription polymerase chain reaction (qRT-PCR) and Western blot were used to detect CD11b, interleukin-1β (IL-1β), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), MMP-9, and p38 MAPK expression. Macrophages were stimulated with Pg-LPS, conditioned medium (CM) and exosomes (exo) were collected and co-cultured with osteoclast precursor cells. MMP-9 and p38 MAPK expression and osteoclast differentiation tartrate-resistant acid phosphatase (TRAP staining) were evaluated. The role of p38 MAPK was further tested by injecting exosomes locally with/without the p38 inhibitor SB203580, and by adding SB203580 to co-cultured precursors. Results: Ligature-induced periodontitis increased bone loss and elevated inflammatory and targeted molecule expression. In vitro, LPS-CM/exo enhanced MMP-9 and p38 MAPK expression and osteoclastogenesis, however, the effects were inhibited by SB203580 (P<0.05). Conclusion: Exosomes derived from Pg-LPS-activated macrophages promote osteoclast differentiation via the p38 MAPK/MMP-9 signaling pathway, which drove periodontal bone loss.

Objective: To investigate the clinical feasibility and preliminary efficacy of the Dahl Concept in the restorative treatment of localized anterior tooth wear. Methods: A total of 8 patients with insufficient restorative space caused by localized anterior tooth wear were enrolled in this study. The local occlusal elevation appliance (Dahl splint) was adopted to minimally invasively increase the intermaxillary distance, followed by the completion of fixed restorations. The treatment cycle and the amount of increased occlusal space were recorded. Cone-beam computed tomography (CBCT) was performed before treatment and prior to the fabrication of the final restorations to observe the temporomandibular joint (TMJ) as well as the pulp, periodontal, and root conditions of the treated teeth. Regular follow-up was conducted after the completion of restorations. Results: The treatment cycle from the application of the Dahl splint to the restoration of extensive occlusal contact ranged from a minimum of 2 months to a maximum of 5 months, with a median of 3.9 months. The follow-up period varied from 1 year (minimum) to 3 years (maximum). Finally, all patients regained extensive occlusal contact of the entire dentition, with the occlusal space increased by (1.5-4) mm and a mean increase of (2.5±0.4) mm. No widening of the periodontal ligament space, root resorption or alveolar bone resorption was observed in the treated teeth, and no significant imaging changes were found in the temporomandibular joints. Conclusion: When insufficient restorative space is caused by localized anterior tooth wear or defect, the Dahl Concept is an effective, conservative, and relatively safe solution. However, more high-quality clinical researches are required in the future to observe its long-term clinical efficacy.

Objective: To investigate the effects of water-air spray cooling modes and laser energy parameters of erbium doped yttrium aluminum garnet (Er:YAG) laser in veneer removal and its safety regarding both soft and hard dental tissues. Methods: An in vitro veneer bonding model was established. Specimens were randomly assigned to two groups based on the presence or absence of water-air spray cooling: Group A (no cooling) and Group B (with cooling). In each group, five incremental energy levels of Er:YAG laser irradiation were applied (Group A: 60-140 mJ; Group B: 140-220 mJ, n=4 per level) until veneer debonding. The debonding time and changes in pulpal chamber temperature were recorded. The tooth surface morphology after debonding was observed using scanning electron microscopy (SEM). Results: Both water-air cooling and laser energy significantly affected the debonding time (P<0.0001). The trend of decreasing debonding time with increasing energy exhibited an "energy threshold": approximately 100 mJ for Group A and 200 mJ for Group B. Beyond these thresholds, further energy increase did not lead to a statistically significant reduction in debonding time. Furthermore, when parameters for both groups were set above their respective thresholds, no statistically significant difference in debonding time was observed (P>0.05). The temperature rise in the pulpal chamber of Group A was significantly higher than that of Group B. SEM observations revealed enamel exposure and damage on all tooth surfaces in Group A, whereas in Group B, only occasional pinpoint enamel exposure was observed at the 220 mJ level. Conclusion: Water-air spray cooling is a necessary safety measure for achieving safe and minimally invasive ceramic veneer removal with Er:YAG laser. For 0.5-mm lithium disilicate glass-ceramic veneers, it is recommended to employ continuous water-air cooling and set the laser energy near the identified threshold (200 mJ) to achieve an optimal "efficiency-safety" balance.

Objective: To compare the shear bond strength (SBS) of a novel one-step light-cured adhesive resin with two conventional two-step adhesive resins and evaluate their performance differences in bonding metal and ceramic orthodontic brackets. Methods: Standardized bonding molds (resin layer thickness 0.3 mm) were fabricated using maxillary first premolar crown models and 3D printing technology. ANOVA was used to compare the SBS of three resins (A: 3M, B: XIHUBIOM, C: OO, n=20). 120 extracted first premolars were divided into two main groups (metal/ceramic brackets), with each main group further subdivided into three subgroups (n=20) based on resin type. SBS was measured after 0 and 1000 thermal cycles, and multifactorial ANOVA combined with Tukey test was used for statistical analysis. Results: Resin cohesive strongth: Group A [(22.65±1.95) MPa] was significantly higher than Group C [(20.83±1.51) MPa], which in turn was significantly higher than Group B [(18.31±2.07) MPa, P<0.05]. In bracket bonding tests, for metal brackets, SBS of Group A [(21.39±1.90) MPa] significantly exceeded that of Groups B [(17.12±2.16) MPa] and C [(18.37±2.06) MPa, P<0.05], while no significant difference was observed between B and C. When comparing bracket types within the same resin, only Group A showed significantly higher SBS with metal than with ceramic brackets (P<0.05). Groups B and C showed no bracket-type-related differences. After thermal cycling, all groups exhibited a slight, non-significant decrease in SBS (P>0.05), with values remaining above the clinical acceptability threshold. Conclusion: The SBS values of novel one-step adhesive resin for both metal and ceramic brackets were intermediate between those of two conventional resin systems, which exceeded the clinically recommended threshold of 6-8 MPa and exhibited excellent resistance to thermocycling-induced aging. This adhesive system simplifies clinical procedures and effectively meets the bonding requirements for both types of orthodontic brackets.

Objective: To evaluate the applicability of Pont's index in Southern Fujian and to establish population-specific equations for predicting maxillary dental arch widths. Methods: A total of 462 adults (198 males, 264 females) from Southern Fujian were enrolled. Digital intraoral scans were obtained and analyzed using FusionAnalyser software to measure the sum of maxillary incisor widths (SI), inter-canine width (ICW), inter-premolar width (IPW), and inter-molar width (IMW). Pont's index was used to predict IPW and IMW. Data were analyzed with SPSS 29.0. Paired t-tests were used to compare the predicted and actual arch widths, and gender differences in tooth and arch widths were assessed. Correlation and linear regression analyses assessed the SI-arch widths relationship and established corresponding prediction equations. Results: Pont's index significantly overestimated arch widths, with mean differences of 3.28 mm for IPW and 3.46 mm for IMW (P<0.001). SI was positively correlated with ICW, IPW, and IMW (r=0.616,0.483,0.350, respectively). Males had larger SI and arch widths than females (P<0.001). Gender-specific prediction equations, developed from a training set with a random 2∶1 split, were validated. The validation showed no significant difference between the predicted and measured arch widths (P>0.05). Conclusion: Pont's index has limited applicability in the Southern Fujian population. The newly developed regression equations are more accurate and reliable for predicting maxillary arch widths in this regional group.

Objective: To investigate the effects of torque prescription in maxillary anterior lingual brackets on three-dimensional tooth displacement of anterior and posterior teeth. Methods: A three-dimensional finite element model of maxillary dentition with customized lingual orthodontics was established. Two groups of anterior bracket torque prescriptions were set: Group A, central incisors, lateral incisors, and canines were set at +13°, +10°, and +7°, respectively; Group B, the corresponding teeth were set at +20°, +13°, and +9°, respectively. Without traction forces, the initial tooth displacement in both groups was observed. Results: After the engagement of the 0.017×0.025-inch archwire, the anterior teeth in both groups exhibited crown labial inclination with an intrusive tendency, while the posterior teeth generally showed crown lingual inclination, intrusion, and mesial displacement. The degree of lingual inclination increased from the second premolar to the second molar. Notably, the second molar exhibited a specific displacement trend: palatal cusp intrusion and buccal cusp extrusion. Except for a slight decrease in the crown labial displacement of the canines in Group B, all other tooth displacements in Group B were greater than those in Group A. Conclusions: Presetting crown labial torque in anterior brackets improves anterior torque control, while caution is required to prevent side effects in the posterior region, such as crown lingual inclination and buccal cusp extrusion (especially in the second molars), as well as to maintain the posterior arch width for effective torque expression in the canine region.

Objective: To quantitatively evaluate the accuracy of Reality Capture (RC) photogrammetry in 3D facial reconstruction and to investigate the influence of sex and age on its precision. Methods: This cross-sectional study enrolled 148 orthodontic patients aged 6-30 years, who were divided into six subgroups based on sex and age. The experimental group utilized a DSLR camera for circular photography and 3D modeling via RC software. The control group obtained data using an RDS Face scanner. Root mean square error (RMS) was calculated for the whole face and 22 subregions via Geomagic Wrap software. Results: The mean whole-face RMS was (1.43±0.38) mm. Buccal and perioral regions showed the highest precision (median RMS 0.5-0.65 mm), while the mandibular angle and preauricular regions had the lowest (median RMS approximately 1.5 mm). Age was a primary influencing factor (P<0.001), adults showed significantly lower error [(1.23±0.22) mm] than adolescents and children (P<0.001). The main effect of sex was not significant, but a significant sex×age interaction effect was observed in the mandibular angle region (P<0.01). Conclusion: RC photogrammetry achieves clinically acceptable accuracy, demonstrating its potential to replace or supplement professional scanners. However, precision is significantly influenced by age and anatomical region, necessitating careful clinical application.

Molar-incisor hypomineralization (MIH) is an enamel mineralization defect with an estimated prevalence ranging from 2.4% to 40.2%. It is often overlooked and misdiagnosed as ordinary dental caries in clinical practice. Most reported cases involve pediatric patients, while adult cases are highly prone to misdiagnosis. This paper reports the clinical management of an adult MIH patient to provide guidance for clinical diagnosis and treatment.

Molar incisor malformation (MIM) is a rare dental developmental anomaly characterized by abnormal root development of the first permanent molar and second primary molar and crown defects of the maxillary permanent mesial incisors. Since its naming in 2014, domestic reports of MIM cases remain scarce, and many clinicians still lack sufficient awareness of this disease. This paper reports a case of MIM in a 9-year-old male patient, who received resin restoration for the maxillary central incisors and root canal therapy using bioceramic for the mandibular left first permanent molar under the assistance of a dental operating microscope. At the same time, combined with relevant literature review, the paper aims to provide reference for the selection of treatment plans for this disease.

Metastasizing pleomorphic adenoma (MPA), the rarest malignant subtype of pleomorphic adenoma, exhibits benign histology in both primary and metastatic lesions yet displays aggressive clinical behavior. Only 10 MPA cases have been reported in Chinese literature, none with lymph node metastasis. We present a case of parotid MPA with cervical lymph node metastasis and discuss its diagnostic and therapeutic implications.

This case report presents the examination, diagnosis, and treatment process of a patient with severe periodontitis and skeletal Class Ⅱ malocclusion undergoing combined orthodontic and orthognathic therapy. Before treatment, the patient exhibited deep overjet and deep overbite, bilateral distal occlusion, and extensive alveolar bone loss reaching one-half to one-third of the root length. After comprehensive periodontal systemic treatment, presurgical orthodontic therapy was performed to improve dental compensation, followed by orthognathic surgery to correct the skeletal disharmony between the maxilla and mandible. Postsurgical orthodontic treatment was used to fine-tune the occlusion. Throughout the treatment, strict periodontal maintenance was maintained, plaque control was emphasized, and light forces were applied during orthodontic movement. The combined treatment significantly improved the patient's occlusion, resulting in normal overbite and overjet, with stable and satisfactory occlusal outcomes observed at follow-up.