Search Results (444)

Gears are the core components of transmission systems, and their health status is critical to the safety and stability of the entire system. In order to efficiently identify the typical fault types such as missing teeth and broken teeth in gears, this paper collects a rich sample under complex backgrounds from different shooting angles and lighting conditions. Then a hierarchical approach is used to describe gear faults on the image. The gear samples are first segmented for image extraction and then finely labeled for gear fault regions. In addition, imbalanced datasets are produced to simulate the environment with fewer fault samples in the actual industrial process. Finally, a semi-supervised learning framework is trained based on the above method and applied in actual environment. The experimental results show that the model performs well in gear target detection and fault diagnosis, demonstrating the effectiveness of the proposed method. Full article

Background/Objectives: Untreated dental caries, the single most common health condition globally, is strongly associated with behavioural factors. This study examined dental status and oral health habits in child–parent and sibling pairs. Methods: We retrospectively analysed records from a dental practice in northeastern Poland, including 90 child–parent pairs and 27 sibling pairs. Dental status was assessed using the Decayed-Missing-Filled Teeth (DMFT) index, and treatment completion was measured with the Dental Treatment Index (DTI). Oral health behaviours were also evaluated. Results: Significant differences between children and parents were observed only in the mild-to-moderate caries groups (DMFT I: 27 children vs. 12 parents; DMFT II: 15 children vs. 32 parents). No differences were found in the severe caries or caries-free groups. Children had lower treatment completion than parents in the poorest care group (DTI 1: 20 children vs. 7 parents), but similar outcomes in higher DTI categories. Among siblings, differences appeared only in the DMFT I group, with no differences in treatment completion or behaviours. Conclusions: Strong similarities in extreme dental characteristics between children and parents, comparable DTI values in most groups, and consistent sibling outcomes suggest that family environment strongly influences oral health. Full article

Background/Objectives: The ongoing prevalence of dental issues within the school-age population continues to present significant public health challenges. This study aims to thoroughly evaluate the oral health conditions of schoolchildren aged 7–10 years, with a particular focus on identifying the prevalence and severity of dental caries, as well as their relationship with dental hygiene and dietary habits. Methods: A cross-sectional approach was employed involving 700 children aged from 7 to 10 years, recruited from nine urban and rural educational institutions across two Romanian counties, namely Mureș and Bistrița-Năsăud. Data were collected regarding the sociodemographic characteristics of participants, including parental educational background and occupational status. Furthermore, information on dental hygiene routines was gathered, encompassing tooth brushing habits, flossing usage, frequency of brushing, along with dietary details such as daily meal count, snacking frequency, and sugar intake levels. An oral examination was performed by a trained specialist to assess the condition of the children’s teeth, documenting the number of decayed, missing, and filled teeth. The presence of plaque was evaluated using a plaque index, and the dental caries status was quantified using the Decayed, Missing, and Filled Teeth (DMFT) index. Results: The findings revealed that the average plaque score was marginally higher in boys (mean = 0.69 ± 0.36) compared to girls (mean = 0.65 ± 0.40). Additionally, children from urban environments demonstrated a mean plaque score of 0.61 ± 0.32, whereas their rural counterparts exhibited a higher score of 0.73 ± 0.38. In multivariable models, irregular brushing, higher daily sugar consumption, and ≥3 snacks/day were independently associated with both caries prevalence (DMFT > 0) and greater DMFT counts (p < 0.05). Conclusions: The evidence denotes a concerning association between poor oral hygiene practices and higher rates of tooth decay among children, particularly among those with elevated sugar intake and frequent snacking behaviors. Dental public health professionals are encouraged to incorporate considerations of oral hygiene habits when developing future health promotion strategies aimed at improving the oral health status of children. Full article

To address the limitation regarding the supervised dataset scale in the semantic recognition of newly distributed types such as wisdom teeth and missing teeth, the multi-encoding contrastive learning for dual-stream self-supervised 3D dental segmentation network (MECSegNet) is proposed. First, a self-supervised encoder pre-training framework is designed by integrating 3D mesh feature representation to construct a deep feature encoding network, where the pre-trained encoder learns universal dental feature representations. Then, a multi-contrastive loss function is established to jointly optimize the self-supervised encoder, extracting effective local and global feature representations while incorporating a cross-stream contrastive loss to learn discriminative features from multiple perspectives. Finally, the improved encoder is integrated into a dual-stream network to build a fine-tuning framework for supervised fine-tuning on a small proportion of labeled data. Experimental results show that, with only 20% labeled data, the proposed MECSegNet achieves a 1.3% improvement in accuracy and a 79.81% reduction in computational cost compared to existing self-supervised methods, while maintaining comparable segmentation accuracy and efficiency to high-performance fully supervised methods. Full article

Objectives: The aim of this study was to evaluate the performance of GPT-4o in identifying nine common dental conditions on panoramic radiographs, both overall and at specific tooth sites, and to assess whether the use of different tooth numbering systems (FDI and Universal) in prompts would affect its diagnostic accuracy. Methods: Fifty panoramic radiographs exhibiting various common dental conditions including missing teeth, impacted teeth, caries, endodontically treated teeth, teeth with restorations, periapical lesions, periodontal bone loss, tooth fractures, cracks, retained roots, dental implants, osteolytic lesions, and osteosclerosis were included. Each image was evaluated twice by GPT-4o in May 2025, using structured prompts based on either the FDI or Universal tooth numbering system, to identify the presence of these conditions at specific tooth sites or regions. GPT-4o responses were compared to a consensus reference standard established by an oral-maxillofacial radiology team. GPT-4o’s performance was evaluated using balanced accuracy, sensitivity, specificity, and F1 score both at the patient and tooth levels. Results: A total of 100 GPT-4o responses were generated. At the patient level, balanced accuracy ranged from 46.25% to 98.83% (FDI) and 49.75% to 92.86% (Universal), with the highest accuracies for dental implants (92.86–98.83%). F1-scores and sensitivities were highest for implants, missing, and impacted teeth, but zero for caries, periapical lesions, and fractures. Specificity was generally high across conditions. Notable discrepancies were observed between patient- and tooth-level performance, especially for implants and restorations. GPT-4o’s performance was similar between using the two numbering systems. Conclusions: GPT-4o demonstrated superior performance in detecting dental implants and treated or restored teeth but inferior performance for caries, periapical lesions, and fractures. Diagnostic accuracy was higher at the patient level than at the tooth level, with similar performances for both numbering systems. Future studies with larger, more diverse datasets and multiple models are needed. Full article

Background and Objectives: Cone Beam Computed Tomography (CBCT) offers high-resolution, three-dimensional imaging for detecting apical periodontitis (AP) and evaluating the technical quality of endodontic treatments. This study aimed to investigate the diagnostic value of CBCT in identifying endodontic failures and periapical lesions and to explore the clinical patterns associated with these findings in a Romanian patient cohort. Materials and Methods: A retrospective study was conducted on 258 patients (with 876 root canal-treated teeth), all of whom underwent CBCT imaging between October 2024 and April 2025 at a private radiology center in Craiova, Romania. Of the 876 treated teeth, 409 were diagnosed with apical periodontitis. Patients were present for endodontic treatment at the Endodontics Clinic of the Faculty of Dentistry, University of Medicine and Pharmacy of Craiova. With the patients’ consent, 3D radiological examinations were recommended for better case planning and accurate diagnosis. The periapical status and technical parameters of root canal fillings were assessed using the CBCT-PAI index and evaluated by three calibrated observers. Associations with demographic, clinical, and behavioral factors were statistically analyzed. Results: Apical periodontitis was detected in 46.69% of the teeth examined during the study period, with CBCT-PAI score 3 being the most prevalent. Poor root canal obturation quality (underfilling, overfilling, and voids) was significantly associated with periapical pathology. Chronic lesions were more common than acute ones, especially in older patients. The number of teeth with endodontic treatments and no AP, as well as the number of teeth with AP, was significantly lower for patients with acute AP, indicating the more severe impact of chronic AP on the patients’ oral health status. CBCT allowed the precise localization of missed canals and assessment of lesion severity. Conclusions: Within the limits of a retrospective, referral-based cohort, CBCT aided the detection of periapical pathology in root canal-treated teeth (46.69%). These findings do not represent population-based rates but support the selective use of CBCT, in line with current ESE guidance, for complex cases or when conventional imaging is inconclusive. Full article

Aim: To compare the fracture resistance of teeth with varying degrees of residual coronal dentine after restoration using two fibre-reinforced composite core materials. Materials and Methods: Seventy extracted human lower premolars were divided into four groups: sound (control), one missing proximal wall (Cl-II), two missing proximal walls (MOD), and endocrown (EC). Subgroups were restored with either a short fibre-reinforced flowable composite (EverX Flow) or an experimental fibre-reinforced composite. Except for the control, teeth underwent endodontic treatment and were restored accordingly. Fracture resistance was tested using a universal testing machine. Statistical analysis compared fracture resistance across groups. Results: Teeth in EC exhibited the highest fracture resistance (1153.43 ± 332.52 N), comparable to sound teeth (1114.03 ± 185.58 N) and not significantly different from the experimental composite group (1006.89 ± 200.51 N) (p = 0.304). Cl-II restorations with EverX had significantly lower strength (652.48 ± 314.04 N) compared to MOD (773.02 ± 261.18 N) and EC (p < 0.05). The experimental composite showed a similar trend, with MOD having the lowest strength (408.6 ± 168.85 N). Significant differences were noted between materials in the MOD group (p = 0.009). Scanning electron microscopy revealed distinct fracture patterns. Conclusions: Endocrowns using direct fibre-reinforced composites provided protection for endodontically treated teeth with higher fracture resistance compared to teeth with MOD and Cl-II cavities. This gives direct composite endocrowns a potential for high-stress applications, though design and material selection remain critical. Full article

Background: This study investigates the diagnostic reliability of an artificial intelligence (AI)-based software (Diagnocat) in caries, dental restorations, missing teeth, and periodontal bone loss on panoramic radiographs (PRs), comparing its performance with evaluations from three independent dental experts serving as ground truth. Methods: A total of 104 PRs were analyzed using Diagnocat, which assigned a likelihood score (0–100%) for each condition. The same images were independently evaluated by three experts. The diagnostic performance of Diagnocat was evaluated using sensitivity, specificity, and receiver operating characteristic (ROC) curve analysis, while inter-rater agreement was assessed through Cohen’s kappa (κ). Results: Diagnocat showed high overall sensitivity (99.2%), identifying nearly all conditions marked as present by human evaluators. Specificity was low (8.7%), indicating a tendency to overdiagnose. Overall accuracy was 96%, likely influenced by the coexistence of multiple conditions. Sensitivity ranged from 77% to 96%, while specificity varied: dental restorations (66%), missing teeth (68%), periodontal bone loss (71%), and caries signs (47%). The agreement was fair for dental restorations (κ = 0.39) and missing teeth (κ = 0.37), but poor for caries signs (κ = −0.15) and periodontal bone loss (κ = −0.62). Conclusions: Diagnocat shows promise as a screening tool due to its high sensitivity, but low specificity and poor agreement for certain conditions warrant cautious interpretation alongside clinical evaluation. Full article

Background: To evaluate the fracture resistance of 3D-printed 3-unit fixed dental prostheses (FDPs) made from tetragonal zirconia polycrystal (3Y-TZP). Methods: Based on a maxillary typodont model with a missing first molar and neighboring teeth with full crown preparations, FDPs differing in wall thickness (d = 0.6 mm / d = 0.8 mm / d = 1.0 mm) were designed. For all test groups, 12 samples were fabricated from 3Y-TZP by either 3D-printing or milling. For 3D-printing, pontic designs were modified by basal slots to enable regular firing times. After luting on CoCr dies, samples underwent artificial aging. Loads tilted by 30° were applied on the mesio-buccal cusp of the pontic, and fracture resistance F_u was assessed. Welch ANOVA and Dunnett-T3 tests were used for statistical evaluation. Results: Significant differences in F_u were identified (Welch ANOVA, p < 0.001). For milled FDPs, fracture originated from connector areas, and F_u increased with increasing wall thickness (d = 0.6 mm: 1536 ± 131 N, d = 0.8 mm: 2226 ± 145 N, d = 1.0 mm: 2686 ± 127 N, significant differences but for the comparison d = 0.8 mm vs. d = 1.0 mm). For 3D-printed FDPs, the loaded cusp fractured, and F_u did not change with FDP wall thicknesses (p > 0.779, F_u = 1110 ± 26 N for all PZ FDPs). Milled FDPs showed significantly higher F_u when compared to 3D-printed FDPs with identical wall thickness. Conclusions: Although 3D-printed zirconia FDPs still show lower fracture resistance values than their milled counterparts, all tested FDP configurations clearly exceed the clinical reference thresholds and can therefore be recommended for clinical use. Full article

Introduction: The aim of this study was to investigate the spatial relationship between the incisive canal (IC) and apical region of the maxillary central incisors in the Korean population, using cone-beam computed tomography (CBCT) imaging. The findings are intended to inform and improve the planning and execution of immediate implant placement in the maxillary esthetic zone. Materials and methods: CBCT data were collected from 94 patients (48 men, 46 women) aged 20–79 years at Gangnam Dental Clinic, Seoul, South Korea. The sample was divided according to age into three groups: 20–39 years, 40–59 years, and 60–79 years. Exclusion criteria included missing maxillary anterior teeth, severe crowding, periodontitis, pathology, and image artifacts. Measurements of the distance from the root apex to the incisive canal (RIC-11-P, RIC-21-P) and from the root apex to the buccal bone (RBB-11-B, RBB-21-B) were taken from CBCT images. Statistical analyses were conducted using Welch’s t-test, ANOVA, and Pearson correlation, with significance set at p < 0.05. Results: The mean distances from the root apex to the incisive canal were 3.77 mm (RIC-11-P) and 3.62 mm (RIC-21-P), while the mean distances to the buccal bone were 0.86 mm and 0.94 mm, respectively. Males exhibited significantly greater distances compared to females, both in the NPC-to-root apex and buccal bone measurements. Age-related variations were observed, with younger individuals showing shorter distances from the IC to the root apex. However, ANOVA tests and Pearson correlation analysis indicated no statistically significant correlation in these distances across different age groups. The study highlights significant gender differences in maxillary central incisor anatomy, with males having larger distances from the root apex to both the IC and buccal bone, which has implications for implant placement. While age-related changes were observed, they did not significantly affect the mean distances in a statistically meaningful way. Conclusions: These findings underscore the need for personalized treatment planning in immediate implant placement, particularly in relation to gender and age. Comparisons with other population studies suggest that these anatomical differences may be consistent across various ethnic groups, though individual variance factors should still be considered. Full article

Background: Dental veneers have gained growing interest recently as an aesthetic dental treatment. However, the public’s understanding of veneers’ benefits and risks is unclear. Aim: To assess the awareness and knowledge of the public about dental veneers in Saudi Arabia. Methods: This cross-sectional study employed an Arabic questionnaire, which consisted of three sections: demographic information, awareness about oral hygiene, and awareness about dental veneers. Correct responses to knowledge questions were assigned one point, and all points were summed to calculate the total knowledge score. Results: The study included 340 eligible respondents, out of whom 51 (15%) used veneers. Most responses to knowledge questions were correct. However, more than half of the participants wrongly thought that dental veneers are indicated for the correction of severely crowded teeth or to replace missing teeth, and 40.3% did not know that they require the removal of tooth structure. A low knowledge score about dental veneers was significantly related to male gender (p < 0.001), non-Saudi nationality (p = 0.005), attending medium/high schools only (0.014), and working in jobs outside the dental field (p = 0.036). Conclusions: The public’s knowledge regarding dental veneers in Saudi Arabia is fair but requires improvement to correct some misconceptions regarding the benefits and risks associated with the installation of veneers. The defects in knowledge identified by the present study should be addressed in patient education initiatives to improve patients’ understanding, align patients’ expectations, and help informed decision-making. Full article

Background: Incarcerated individuals often experience poor oral health due to limited access to care and socioeconomic disadvantages. Objective: This study assessed the dental health status of incarcerated individuals in Silesia over a five-year period using the Decayed, Missing, and Filled Teeth (DMFT) index and compared their outcomes to a matched control group from the general population. Methods: We conducted a retrospective observational case-control study at the University Centre for Dentistry in Bytom, reviewing records of 136 incarcerated patients (mean age 36.8 ± 7.9 years; 9.4% women) and a matched control group between 2019 and 2024. Results: Incarcerated individuals had a higher mean DMFT score (14.4 ± 5.7) compared to controls (11.5 ± 6.5; mean difference = 2.95, 95% CI: 1.53 to 4.37; Cohen’s d = 0.49), with more decayed (4.9 ± 3.2 vs. 3.4 ± 2.4) and missing teeth (4.3 ± 3.2 vs. 3.5 ± 2.6). Most incarcerated patients (65.5%) required oral surgical treatment, most commonly for retained roots (25.9%) and impacted teeth (24.5%). No significant DMFT differences were observed based on age or sex, although disparities were most pronounced in older female prisoners (mean DMFT 17.8 vs. 9.8 in controls aged 40+). Conclusions: Incarcerated individuals in Silesia demonstrated a significantly higher burden of untreated dental disease and greater tooth loss compared to non-incarcerated controls over the five-year period. The predominance of advanced dental conditions requiring surgical intervention highlights missed opportunities for early and preventive care in this vulnerable population. Full article

Immigrants represent 20.8% of Norway’s population, with 22.2% aged 50+. This study aimed to assess oral health-related behaviors and perceived oral health in relation to sociodemographic factors among elderly immigrants aged 50+. Methods: 174 participants (94% response rate). Data on sociodemographic, oral hygiene, diet, snus use, xerostomia, and halitosis were collected using the self-reported questionnaire. p-value < 0.05 indicates statistical significance. Results: Participants’ mean age was 60.7, with 60% reporting poor self-perceived oral health, and over 64% had missing teeth. Participants reported poor oral hygiene habits (35.1%, n = 61), frequent sugar consumption (51.1%, n = 89), and smoking (16.1%, n = 28). Poor oral health was more common in those aged 60 and over (OR = 2.5, CI: 1.1–5.8) and with a narrow social network (OR = 3.8, CI: 1.7–8.5). Women had lower odds of sugar consumption (OR = 0.38, CI: 0.18–0.8) and smoking (OR = 0.27, CI: 0.09–0.7), but living in Norway for less than 3 years increased smoking odds (OR = 4.5, CI: 1.2–15.8). Moreover, being unmarried (OR = 5.5, p = 0.008), recent immigration (OR = 24.3, p < 001), and a narrow social network (OR = 4.7, p = 0.004) were associated with higher odds of missing teeth. Conclusions: Elderly immigrants in Norway reported poor oral health, tooth loss, and unhealthy dietary and hygiene habits, highlighting the need for targeted interventions. Full article

Background. Post-treatment apical periodontitis (PAP) is a frequent consequence of root canal treatment (RCT) failure, often caused by untreated missed canals in root-filled teeth (RFT). While cone-beam computed tomography (CBCT) has been used to find these missed canals, the results are controversial. This systematic review and meta-analysis investigates the association between PAP in RFT and missed canals detected via CBCT. Methods. Two independent reviewers searched PubMed, Scopus, Dialnet, and SciELO for relevant articles published up until 17 February 2025. The main outcome was the prevalence of PAP in RFT with and without missed canals detected via CBCT. The overall odds ratio (OR) was calculated using a binary random effects model meta-analysis (OpenMeta Analyst). Risk of bias was assessed using the Newcastle–Ottawa Scale, and certainty was evaluated using GRADE. Results. Eight cross-sectional studies (9983 RFT) were included in the review. The pooled prevalence of PAP was significantly higher in RFT with missed canals (85.1%) than those without (56.3%). The meta-analysis showed a strong association between missed canals and PAP (OR = 7.17, 95% CI = 4.55–11.29), indicating a sevenfold increased likelihood. Maxillary molars, especially first molars, most commonly had missed canals. Heterogeneity was high (I² = 86%), and evidence certainty was low, due to methodological limitations. Conclusions. Untreated missed canals significantly increase the likelihood of PAP in RFT, highlighting the need for thorough canal detection and treatment. Clinicians should prioritize anatomical knowledge and advanced imaging to minimize treatment failure. Full article

Background/Objectives: Official data on the oral health of young children in Romania are limited, especially concerning the societal shifts following the COVID-19 pandemic. This study aimed to compare the oral health status, hygiene habits, diet, and dental care patterns of 6-year-old children in a rural Romanian region before and after the pandemic. Methods: A cross-sectional survey studied two groups of 6-year-olds from rural Transylvania: Group 1 (n = 77), assessed 2018–2020 pre-pandemic, and Group 2 (n = 136), assessed in 2024 post-pandemic. Clinical data used the Decayed, Missing, and Filled Teeth (DMFT) index. Parents completed questionnaires on oral hygiene, diet, dental visits, and pandemic-related topics for Group 2. Chi-square, Student’s t-tests, and a multiple linear regression were used to analyze the data. Results: Post-pandemic, 70% of children brushed twice daily, up from 26%. Despite this, negative outcomes increased: the number of affected teeth rose from 6.8% to 29.6% (p < 0.001), sugar intake increased, and dental visits became more reactive, with pain being the main reason for 61% of post-pandemic visits, compared to 17% pre-pandemic. Conclusions: This study reveals a significant oral health paradox: despite a three-fold increase in recommended toothbrushing, caries experience in permanent teeth increased four-fold. This outcome was driven by a high-risk environment of more cariogenic diets and reduced preventive care, with lower maternal education also identified as a key independent risk factor. These findings show that promoting hygiene alone is insufficient, underscoring the urgent need for public health programs that integrate nutritional counseling, improve access to preventive care, and address underlying socioeconomic disparities. Full article