Purpose: Declines in masticatory function have been reported to be closely associated with cognitive impairment and reduced brain activity in older adults. This study aimed to investigate the effects of intraoral vibratory stimulation on masticatory function, cognitive performance, and brain activity in elderly individuals and to evaluate its potential efficacy. Materials and Methods: Participants were divided into a vibration-stimulation group (n=9) and a non-vibration control group (n=7). Baseline assessments were conducted at the first visit. Participants then received either vibratory stimulation or a wash-out (control) condition for two weeks, followed by the same assessments at the final visit. Evaluation measures were dental assessments (maximum bite force, masticatory performance, and salivary flow rate), cognitive tests (CANTAB, paper-based and computerized tests), quantitative electroencephalography (qEEG), and functional magnetic resonance imaging (fMRI) during a short-term memory task. Results: No significant long-term effects or statistically meaningful differences were observed between the two groups in cognitive performance or brain activity. Similarly, no pre- to post-intervention differences were found between groups in dental measures related to masticatory function (maximum bite force, masticatory performance, and salivary flow rate). Due to the limited sample size, this study functioned as a pilot study focusing on descriptive rather than inferential statistical analysis. Conclusion Intraoral vibratory stimulation did not demonstrate immediate or clear effects on cognitive function or brain activity in older adults, suggesting the need for optimization of stimulation parameters such as location and intensity. Future studies with larger sample sizes and improved stimulation methods replicating masticatory function are warranted to further explore the potential cognitive benefits.

A 58-year-old woman presented with swelling and pain in the right submandibular region. Clinical examination revealed mild tenderness and firm consistency without intraoral findings. Contrast-enhanced computed tomography demonstrated a well-defined radiopaque mass at the inferior border of the right mandible, surrounded by a radiolucent rim. The lesion was surgically excised via a submandibular approach, and histopathological analysis confirmed it as a supernumerary tooth. Supernumerary teeth are relatively common developmental anomalies; however, ectopic impaction at the mandibular inferior border is exceptionally rare. The etiology of ectopic tooth remains unclear, but may be related to aberrant dental lamina development or abnormal neural crest cell migration during embryogenesis. This case underscores the importance of considering ectopic supernumerary teeth in the differential diagnosis of radiopaque lesion of the jaw. Surgical removal is effective for symptom relief and prevention of further complication.

Oroantral communication (OAC) is a common complication associated with implant failure and maxillary posterior teeth extraction, and while various flap techniques provide reliable soft-tissue closure, reconstruction of the underlying bony defect often requires extensive procedures or autogenous bone harvesting. This report presents a staged, minimally invasive approach that enabled successful OAC closure and implant restoration using allogenic bone alone. A large OAC in the maxillary posterior region was first closed using a palatal rotation flap, chosen for its robust vascularity and preservation of keratinized tissue and vestibular depth—factors advantageous for later implant placement. After adequate soft-tissue healing, bone augmentation was performed using a partial-thickness separation technique that allowed elevation of the inner sinus layer, creating a space analogous to a sinus lift. Freeze-dried bone allograft and a collagen membrane were used, resulting in satisfactory bone formation and enabling subsequent implant placement with stable primary fixation. This case demonstrates that a staged approach can achieve satisfactory clinical outcomes without autogenous grafting, general anesthesia, or extensive surgical morbidity. While further studies are needed, this method offers a practical and less invasive alternative for managing large OACs requiring implant-based rehabilitation.

Purpose: Medication-related osteonecrosis of the jaw (MRONJ) is a complication of antiresorptive therapy, including bisphosphonates and denosumab. Although bone scintigraphy (BS) detects early metabolic changes, its diagnostic role in MRONJ and its role in assessing systemic skeletal involvement remain unclear. This study analyzed BS tracer uptake patterns and their association with MRONJ severity and clinical variables. Materials and Methods: This retrospective study analyzed 319 patients diagnosed with MRONJ from 2010 to 2019. Three-phase BS, cone-beam computed tomography (CBCT), and clinical data were reviewed. Tracer uptake intensity in the jaw was visually graded, and extra-jaw skeletal uptake was categorized by region and number of involved sites. Associations between the MRONJ stage, jaw uptake intensity, and skeletal uptake beyond the jaw were analyzed. Results: Higher tracer uptake intensity in the jaw was associated with advanced MRONJ stages (P<0.001), particularly Stage 3. However, the number of skeletal sites beyond the jaw did not correlate with the MRONJ stage (P=0.512).Distribution of local and systemic tracer uptake in body patterns across MRONJ Stages did not show statistical significance. Conclusion Elevated tracer uptake in the jaw correlates with advanced MRONJ stages and broader skeletal tracer uptake, suggesting a potential link between local disease severity and systemic skeletal involvement. However, skeletal uptake beyond the jaw does not independently predict the MRONJ stage, suggesting that systemic bone involvement alone may not reflect increased disease severity.

Objective: This study aimed to evaluate the survival of removable partial dentures (RPDs) abutment teeth that had undergone root canal treatment (RCT) and to identify the factors influencing survival. Materials and Methods: Records from the Veterans Health Service Medical Center were reviewed to identify patients who received RPDs between 2014 and 2015 and had root canal-treated abutment teeth. Preoperative variables included patient demographics, tooth location, and periapical radiolucency, while postoperative variables included RPD classification, opposing dentition, crown-root ratio (CRR), root canal filling quality, post placement, and restoration type. Statistical analysis was performed using the Kaplan-Meier method and Cox proportional hazards models. Results: A total of 776 root canal-treated abutment teeth from 341 patients using RPDs (mean age, 72.03 years) were included. In the multivariate analysis, tooth-related conditions such as arch type and tooth location, presence of a periapical lesion, and presence of a core were significantly associated with poor prognosis. Kaplan-Meier survival analysis revealed that the 3-, 5-, 7-, and 10-year survival rates for all teeth were 93.5%, 84.4%, 77.1%, and 60.0%, respectively. Conclusion Arch type and tooth position, preoperative periapical radiolucency, and type of restoration are significantly associated with prognosis in patients with RPDs in whom the abutment teeth have previously undergone RCT.

Purpose: This study compared the efficacy of different irrigation methods for the removal of Ca(OH)2 paste from the root canal. Materials and Methods: The root canals of 75 human mandibular premolars with standardized 15-mm canal lengths were prepared using nickel-titanium rotary files. After drying, the canals were filled with Ca(OH)2 paste. The teeth were divided into five groups: Control group (Group C), conventional irrigation; Group EA, sonic activation (EndoActivator); Groups EQA and EQB, sonic activation (EQ-S with metal tips A and B, respectively); and Group EU, ultrasonic activation (EndoUltra).The Ca(OH)2 paste volume before and after irrigation was measured using micro-computed tomography (CT) images. One specimen from each group was bisected along the long axis, and the canal walls were evaluated at 100× magnification using a scanning electron microscope. Statistical analyses were performed using Kruskal-Wallis and Mann-Whitney U tests. Results: Overall, Ca(OH)2 paste removal was higher in Group EQA than in Group C. In the coronal third, removal rate was higher in Group EQA than in Group C. In the middle third, Groups EQB and EU outperformed Group C. Removal from the apical third was higher in Group EQA than in Group C. All groups showed greater removal from the coronal and middle thirds than from the apical third. Conclusion Sonic and ultrasonic irrigation methods demonstrated higher efficacy than conventional irrigation method for the removal of Ca(OH)2 paste from the root canal. All groups demonstrated better effectiveness in removal from the coronal and middle thirds than from the apical third.

Objective: This study aimed to identify factors associated with the recovery of mandibular nerve disturbance and to predict the possibility of recovery tailored to individual patients. Materials and Methods: Patients who visited the dental hospital with symptoms of mandibular nerve disturbance from April 2015 to September 2020 were studied. Patients were divided into two groups based on treatment outcomes: recovered or non-recovered. Variables related to recovery included age, sex, onset event of the nerve disturbance, affected area, imaging findings, and treatment methods. The correlation between recovery and these variables was analyzed using the Chi-square test and Fisher’s exact test. Results: A total of 328 patients were included in the study.Among the variables associated with recovery, the onset event of the symptom (P-value=0.02) and imaging findings (P-value=0.04) were statistically significant. Among the significant variables, the highest proportion of patients (77.78%) recovered without symptoms of onset event, while implant surgery showed the lowest recovery rate (34.25%). Regarding imaging findings, the recovery rate was highest in cases of suspected canal damage (58.82%), while no patients recovered from compression of the canal (0.00%). Conclusion This study highlights the importance of large-scale data analysis and a thorough evaluation of clinical variables to understand mandibular nerve disturbances. The findings provide a basis for improving treatment strategies and reducing the impact of nerve disturbances on patients’ quality of life.

Purpose: This study aimed to perform a genome characterization of Streptococcus mitis KHUD 011, a strain isolated from the oral microbiome of a healthy Korean individual, and to compare its genomic features with other S. mitis strains. Materials and Methods: The strain was identified through 16S rRNA gene sequencing, and its genome was sequenced using the PacBio Sequel II platform. De novo assembly and annotation were performed, followed by comparative genomic analysis with three additional strains (S. mitis NCTC 12261, S022-V3-A4, and B6). Pan-genome and phylogenetic analyses were conducted to identify strain-specific genes and assess inter-strain genomic diversity. Results: The genome of S. mitis KHUD 011 consisted of 1,782 protein-coding genes, with a G+C content of 40.24%. Pan-genome analysis identified 1,263 core gene clusters (50.0%), 496 dispensable clusters (19.7%), and 763 strain-specific clusters (30.3%). KHUD 011 displayed 88 strain-specific genes, particularly associated with cell wall/membrane biogenesis, transcriptional regulation, and carbohydrate metabolism. Phylogenetic analysis placed KHUD 011 closely with NCTC 12261, forming a distinct cluster apart from other strains. Conclusion The genome characterization of S. mitis KHUD 011 underscores substantial inter-strain genomic diversity influenced by host interactions, ecological niches, and health status. The identified strain-specific genes, particularly those associated with cell wall/ membrane biogenesis, transcriptional regulation, and carbohydrate metabolism, suggest adaptations to the oral microbiome and its interaction with the host. These findings highlight the ecological versatility of S. mitis and the importance of exploring strains from diverse environments to better understand their role within the host and the broader microbiome.

Purpose: The opacity of zirconia sometimes requires a veneering material; thus lithium disilicate, a veneer material with excellent strength, can be used. This study investigated the fracture resistance of zirconia–lithium disilicate (Zr-LS2) bi-layered crowns according to the design of the substructure. Materials and Methods: Five groups of posterior Zr-LS2 restorations (Zirtooth and Amber LiSi-POZ) were fabricated with different zirconia substructure coverage (control group, groups half occlusal zirconia coverage; 1/2OZ, and three-quarter occlusal zirconia coverage; 3/4OZ) and margin designs (control group, groups collar margin; C-M, and collarless margin; Cl-M). All restorations were cemented with self-adhesive resin cement followed by 24-h water storage and thermocycling (10,000 cycles, 5°C and 55°C). The fracture load was measured, and failure mode analysis, fractography, and elemental analysis were performed. The one-way analysis of variance and Fisher’s exact test were performed for statistical analyses (α=.05). Results: A significant difference was found in the fracture load of Zr-LS2 restorations according to the zirconia coverage of the occlusal area and margin design (P<.05). Group 3/4OZ was significantly larger than the control group C and 1/2OZ (P<.05). The C-M group had greater fracture loads based on margin design than the control group C and Cl-M (P<.05). Conclusion The fracture resistance of posterior Zr-LS2 restorations increased with the zirconia coverage, occlusal thickness, and collar margin.

Purpose: To estimate the sample size required for developing artificial intelligence (AI) that can predict soft-tissue and alveolar bone changes following orthodontic treatment. Materials and Methods: From the original data sets with N=887, consisting of 132 input and 88 output variables used to create AI models for predicting treatment changes following orthodontic treatment, six subsets of the data (n=75, 150, 300, 450, 600, and 750) were generated through random resampling procedures. The process was repeated four times, resulting in 24 different data subsets. Each data subset was used to create a total of 24 AI models using the TabNet deep neural network algorithm. The clinically acceptable prediction accuracy was defined as a less than 1.5 mm prediction error on the lower lip. The prediction errors from each AI model were compared according to sample sizes and analyzed to estimate the optimal sample size. Results: The prediction error decreased with increasing sample sizes. A training sample size greater than approximately 1650 was estimated to develop an AI model with less than 1.5 mm of prediction errors at the lower lip area. Conclusion From a statistical and research design perspective, a considerable amount of training data appears necessary to develop an AI prediction model with clinically acceptable accuracy.