Journal of prosthodontic research最新文献

Purpose: The molecular mechanisms guiding osseointegration and soft tissue sealing remain poorly understood. Additionally, conventional assays provide limited insight. RNA sequencing (RNA-seq) offers an unbiased, genome-wide profiling of biological events. This review summarizes RNA-seq applications in implant research, highlighting current evidence and future opportunities.

Study selection: A structured search was conducted in PubMed to identify studies that included RNA-seq analyses with titanium surface experiments, including in vitro experiments with osteoblasts/mesenchymal stem cells, fibroblasts, macrophages, soft tissue cells, and in vivo animal models. An overview of the RNA-seq methodology and emerging applications of biomaterials was also included in the search.

Results: RNA-seq contributions comprised three categories: (1) confirmation of known responses, such as upregulation of osteogenic differentiation genes on microrough surfaces; (2) discovery of novel functions, including non-canonical Wnt signaling, oxidative stress regulators, and non-coding RNAs mediating osteogenesis and immune modulation; and (3) mechanistic explanations of paradoxes, such as the osteoblast "dilemma" of reduced proliferation but enhanced differentiation. Fibroblast studies linked ultraviolet-activated titanium to proteoglycan/glycosaminoglycan signaling, and macrophage analyses identified zinc-induced metallothioneins as immunomodulatory biomarkers. In vivo, RNA-seq revealed strontium-driven CDH2/β-catenin signaling, age-related suppression of Wnt/angiogenesis, and keratin-mediated soft tissue sealing. Notably, we presented new RNA-seq data demonstrating distinct osteoblast reprogramming on microrough titanium, including the activation of oxidative stress defense, lipid metabolism, and immune-osteoblast crosstalk.

Conclusions: RNA-seq is highly useful for establishing implant-tissue interactions, validating clinical observations, and revealing mechanistic explanations. Despite limited studies and protocol heterogeneity, RNA-seq offers a transformative framework for biologically informed and immune-smart implants.

Purpose: We evaluated the stress distribution patterns in inlay, onlay, and overlay restorations fabricated from different CAD-CAM materials, including current 3D-printed resins and 3D-printed zirconia, under 300 N vertical loading using finite element analysis (FEA).

Methods: A 3D solid model of a mandibular first molar was generated based on standard anatomical dimensions. Fifteen finite element models were constructed by combining three preparation designs with five restorative materials. A static vertical load of 300 N was applied and distributed across the multipoint occlusal contacts to simulate physiological masticatory forces. The stress distribution was analyzed using the von Mises and Maximum Principal Stress criteria to evaluate both the restoration and the surrounding dental tissues.

Results: Restoration design and material stiffness significantly influenced stress distribution. Among the designs, the overlay preparations exhibited the most favorable biomechanical behavior, showing lower stress transmission to the tooth structure than inlay and onlay designs. Materials with a high elastic modulus (205.000 MPa LithaCon 3Y-210) demonstrated a stress-shielding effect, absorbing higher internal stress while protecting the underlying dentin. Conversely, low-modulus materials (4.030 MPa VarseoSmile Crown Plus) exhibited lower internal stress, but transferred higher stress loads to the tooth-restoration interface and dentin.

Conclusions: The use of overlay designs combined with high-elastic modulus materials offers a biomechanically superior configuration for reinforcing compromised posterior teeth because this combination minimizes stress transmission to the remaining tooth structure. Although low-modulus materials reduce internal restoration stress, they require careful consideration because of the increased stress transfer to the dentin.

Purpose: Commercially pure titanium (CP-Ti) is ideal for removable partial denture (RPD) frameworks owing to its biocompatibility and corrosion resistance; however, conventional casting can introduce defects and dimensional errors. This study compared the shape accuracy, surface roughness, microstructure, and internal pores of CP-Ti RPD frameworks prepared using four CAD-CAM fabrication methods: (1) Ti-resin: casting from a three-dimensional (3D)-printed resin pattern; (2) Ti-wax: casting from a milled wax pattern; (3) Ti-milling: direct milling from a CP-Ti disc; and (4) Ti-SLM: selective laser melting.

Methods: Forty frameworks were prepared for each group (N = 10). Shape accuracy was assessed using 3D data-inspection software, surface roughness was analyzed using laser microscopy, the microstructure was determined using X-ray diffraction, and internal pores were examined using micro-computed tomography. Nonparametric statistics (Kruskal-Wallis and Steel-Dwass tests) were used (P < 0.05).

Results: Ti-SLM achieved the highest trueness (median: 0.00 mm; IQR: 0.09 mm) and precision (median: 0.01 mm; IQR: 0.02 mm), while Ti-milling yielded the lowest surface roughness (median arithmetic mean height: 0.61 µm; IQR: 0.05 µm). Internal pores were absent in Ti-milling and minimal in Ti-SLM (0-1), whereas Ti-resin and Ti-wax produced 319 and 171 pores (median), respectively. Significant inter-method differences were found in shape accuracy, surface roughness, and pore counts (P < 0.05).

Conclusions: The fabrication method affected the dimensional accuracy, surface conditions, crystalline features, and internal pores of the CP-Ti frameworks. Ti-milling and Ti-SLM outperformed the casting-based methods (Ti-resin and Ti-wax) in terms of accuracy and defect reduction. These digital approaches may improve the reproducibility and precision of clinical fabrication of CP-Ti RPD frameworks.

Purpose: The aim of the current systematic review was to compare the internal fit of lithium disilicate crowns, fabricated using conventional heat-pressing versus CAD-CAM milling techniques.

Study selection: A comprehensive literature search was conducted in PubMed, Embase, Scopus, and the Cochrane Library up to December 2025, following PRISMA guidelines and registered in the Open Science Framework. Eleven studies met the inclusion criteria (nine in vitro studies and two clinical trials), of which nine were included in the quantitative synthesis.

Results: The random-effects meta-analysis demonstrated no statistically significant difference in internal fit between heat-pressed and CAD-CAM-milled crowns, although substantial heterogeneity was observed (I²=95%). Sensitivity analysis excluding five methodologically heterogeneous studies revealed a statistically significant pooled effect favoring heat-pressed crowns (MD=-18.92 μm; 95% CI: -29.77 to -8.07; P = 0.008), with markedly reduced heterogeneity (I²=19%). Subgroup analysis suggested that elastomeric impressions may be associated with better internal fit compared with digital workflows, although heterogeneity remained high.

Conclusions: The current evidence does not demonstrate a consistent difference in internal fit between heat-pressed and CAD-CAM-milled lithium disilicate crowns. Further well-designed, standardized clinical studies are needed to confirm these findings.

Patients: Two female patients aged 55 and 65 presented with persistent occlusal discomfort diagnosed as phantom bite syndrome (PBS) despite multiple prosthetic interventions. Neither had significant psychiatric comorbidity. Both underwent psychosomatic evaluation after non-pharmacological approaches proved insufficient. Pharmacotherapy included low-dose amitriptyline at 10-35 mg/day with aripiprazole augmentation at 1 mg/day in Case 1, and low-dose aripiprazole monotherapy at 1 mg/day in Case 2 after amitriptyline intolerance. Both patients showed marked improvement on the Oral Discomfort/Dysesthesia Rating Scale misalignment subscale, achieved stable occlusion without excessive adjustments, and reported no severe adverse effects during 27-33 months of follow-up.

Discussion: These cases show that pharmacotherapy targeting central hypersensitivity can facilitate successful prosthetic rehabilitation, even in patients without major psychiatric comorbidity. Continued medication during definitive prosthetic procedures helped prevent relapse, highlighting the value of integrated psychopharmacological and prosthodontic management. Clear communication, reframing the condition as hypersensitivity, and shared decision-making further improved adherence and long-term stability.

Conclusions: Maintaining pharmacotherapy throughout prosthetic treatment stabilized PBS symptoms, reduced relapse risk, and improved acceptance of definitive restorations. Recognition of possible central nervous system involvement, even without overt psychiatric comorbidity, broadens therapeutic options and supports better outcomes. Future studies should expand clinical case data, refine medication strategies, define optimal treatment timing, and strengthen interdisciplinary collaboration in PBS management.

Purpose: We elucidated the relationships and differences between mandibular movement (MM) and complementary mandibular movement (cMM), defined as the relative motion of the maxilla with respect to the mandible, by analyzing their spatial characteristics, symmetry, and associated rotational axes.

Methods: Twenty-seven healthy participants (mean age, 53.0 years) were examined. Jaw movements, including sagittal border (SAG), lateral excursion-incursion (LAT), and protrusion-retrusion (PRO), were recorded using a six-degree-of-freedom electromagnetic jaw-tracking device. The cMM data were obtained as the inverse matrices of the MM data. The kinematic (KA) and complementary kinematic axes (cKA) were calculated using Shigemoto's method. The symmetry between the MM and cMM was evaluated at the incisal point, kinematic axis point (KAP), and complementary kinematic axis point (cKAP). Furthermore, the spatial relationship between KA and cKA was analyzed.

Results: The MM and cMM displayed partial symmetry near the intercuspal position (ICP); however, none of the movements exhibited complete correspondence. The PRO, which consists of translational motion, demonstrated significantly greater symmetry than the SAG and LAT. The cKA was located 14.14 mm antero-superior to the KA. The maximum displacement at the cKAP (22.68 mm) was significantly larger than that at the KAP (17.85 mm), whereas no significant difference was observed in path thickness (KA: 0.47 mm; cKA: 0.50 mm).

Conclusions: The MM and cMM were not strictly point-symmetric, and their rotational axes (KA and cKA) did not coincide. The accurate recognition of both MM and cMM is essential when applying jaw movement data to CAD-CAM workflows for prosthetic designs.

Purpose: We functionalized a three-dimensionally (3D) printed denture base resin with α-Ag₂WO₄ microcrystals and evaluated its chemical and surface properties, flexural strength, antimicrobial activity, biocompatibility, and inflammatory response.

Methods: Resin specimens were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The surface roughness was evaluated by profilometry and wettability, whereas the surface free energy was determined using a goniometer. The flexural strength of the resin was assessed by three-point mechanical flexural testing. Antimicrobial activity was evaluated against Candida albicans, Staphylococcus aureus, and Escherichia coli in the adhesion and biofilm formation phases by counting colony-forming units (CFU)/mL and using confocal laser scanning microscopy (CLSM). Time-kill curve assays were performed using the Alamar Blue (AB) reagent, and the biocompatibility of the materials was evaluated in a 3D organotypic model of the oral mucosa using AB and CLSM. Inflammatory response was assessed by measuring cytokine production using flow cytometry.

Results: XRD, FTIR, and SEM analyses demonstrated that α-Ag₂WO₄ was incorporated into the resin with its structure preserved. The surface roughness did not change, and the surface free energy increased; however, the flexural strength decreased slightly. The evaluated resins exhibited antifungal and antibacterial effects at both the adhesion and biofilm formation stages. Functionalization did not alter the biocompatibility of the resins and did not cause an exacerbated inflammatory response.

Conclusions: Functionalization of a 3D-printed denture base resin with α-Ag₂WO₄ demonstrated antimicrobial activity without any detrimental effects to the surface, mechanical, and biocompatibility properties of the material.

Purpose: This narrative review aims to provide dental professionals and researchers with a comprehensive overview of YOLO applications in dentistry.

Study selection: A narrative review approach was used in this study. Literature relevant to YOLO models in dentistry was identified and organized thematically into dental domains such as dental caries detection, tooth numbering, dental biomaterials and restorative evaluation, prosthodontics and implant planning and treatment, dental education, salivary biomarker analysis, and oral cancer detection.

Results: YOLO-based models consistently achieved high precision and efficiency across diverse applications. Notable successes include reliable caries detection, automated restoration evaluation, support for prosthodontic and implant planning through cone-beam computed tomography analysis, and enhanced educational platforms that provide real-time feedback to students. Emerging studies have further demonstrated YOLO's role in point-of-care diagnostics through salivary biomarker analysis and the early detection of potentially malignant oral disorders and cancer. Despite these advances, challenges persist, particularly regarding small datasets, variability in imaging protocols, and limited external validation.

Conclusions: YOLO algorithms are a transformative tool in dentistry that enable rapid, accurate, and reproducible image interpretation. Although further validation and standardization are required, YOLO has a strong potential to enhance diagnostics, prosthodontic treatment planning, education, patient-oriented care, and advance dentistry towards greater precision and efficiency.

Purpose: Sleep bruxism (SB) presents diverse clinical manifestations; however, phenotypic classification is limited by a lack of large-scale standardized data. We established a multicenter clinical registry for SB in Japan and explored SB subgroups using the explanatory latent class analysis (LCA).

Methods: We established a multicenter Sleep Bruxism Clinical Registry in seven dental schools across Japan. The registry enrolls adults (≥18 years) who underwent standardized electromyography (EMG) recordings of masticatory muscle activity during sleep, including both dental patients and healthy volunteers. In addition, clinical characteristics related to orofacial conditions, psychosocial factors, and sleep-related symptoms were registered for the enrolled individuals. Participants with EMG-confirmed SB were included in the exploratory LCA to identify the data-driven subgroups.

Results: In total, 910 individuals, including 524 SB-positive cases, were registered. The LCA identified four SB subgroups: younger individuals with few signs and symptoms (subgroup I, 35.3%), middle-aged women with frequent morning symptoms and high self-awareness (subgroup II, 16.2%), middle-aged individuals with marked tooth wear but low grinding-sound reports and self-awareness (subgroup III, 22.3%), and younger individuals with frequent signs and symptoms (subgroup IV, 26.2%). Individuals in subgroups II and IV exhibited significantly more tonic episodes than those in subgroup I, whereas those in subgroup IV exhibited more phasic episodes than subgroups I and II.

Conclusions: A novel multicenter Sleep Bruxism Clinical Registry was successfully established to enable the collection of comprehensive clinical and physiological data. Exploratory LCA revealed four clinical SB subgroups with distinct EMG episode patterns, suggesting an underlying heterogeneity in SB pathophysiology.

Purpose: We evaluated the effects of zirconia tubes on fracture resistance and microleakage of endodontically treated premolars with flared root canals under cyclic loading.

Methods: Sixty-four bovine mandibular incisors were prepared to simulate human premolars and randomly assigned to four core build-up groups (n = 16 per group): composite resin core only (RC), glass-fiber post (FC), zirconia tube (ZC), and zirconia tube with glass-fiber post (ZFC). After crown fabrication and cementation, specimens underwent cyclic loading (10,000 cycles, 50 N, 2 Hz). In each group, eight specimens (n = 8) were evaluated for fracture resistance under 45 degree oblique loading, and eight (n = 8) were evaluated for microleakage using micro-computed tomography (micro-CT) after silver nitrate immersion.

Results: ZC and ZFC exhibited significantly higher fracture resistance than RC (P = 0.004, 0.022) and FC (P = 0.001, 0.047), with no difference between RC and FC or between ZC and ZFC. Microleakage was significantly lower in ZC and ZFC than in RC and FC (all P < 0.001). Leakage in zirconia tube groups was largely confined to the cervical area, whereas RC and FC showed penetration into the root canal. All specimens in each group exhibited fractures extending below the simulated alveolar bone level, corresponding to unfavorable fracture modes.

Conclusions: Zirconia tubes enhanced fracture resistance and reduced microleakage under cyclic loading in endodontically treated premolars. Foundation restorations using zirconia tubes may be a reliable reinforcement option for structurally weakened roots. Further clinical and long-term studies are required to confirm these findings.