Search Results (28)

The occurrence of triplication in the deciduous teeth is rare. However, it can cause several problems in primary dentition, alteration of development, and eruption of permanent successors. Case Presentation: A three-year-old boy presented with an exuberant acute periapical abscess in the left front teeth region of the upper jaw. Examination revealed a presence of a triple tooth involving the central and lateral left primary incisors and a supernumerary tooth. Radiographs showed that the fused teeth had separate roots, pulp chambers and root canals. The implemented treatment was extraction under local anesthesia. After 2 years of observation, surgical exposure of the crowns of the permanent maxillary central incisor was performed. After seven years, the permanent dentition was completed without any sequelae. Discussion: Triple tooth, as observed in this case report, results from the union of three tooth germs, potentially influenced by physical, hereditary, or environmental factors, leading to esthetic and functional issues and increased susceptibility to caries. Treatment is challenging, requiring preventive care, complex endodontic procedures, and, in some cases, extraction with space maintenance to avoid future orthodontic complications. Conclusion: Early diagnosis, an adequate treatment plan and clinical monitoring should be performed, aiming at preventing the possible disturbances. Full article

Background and Clinical Significance: Dental implants are widely used; however, tooth extraction often results in alveolar bone loss and gingival recession, necessitating bone and connective tissue reconstruction, especially in the esthetic anterior regions. To address these issues, implants are occasionally connected to adjacent teeth, but this remains controversial, as complications (e.g., intrusion of natural teeth) have been observed. This report demonstrates the long-term success of implants replaced after removing maxillary bilateral central incisors and connecting them to lateral incisors with reduced supportive bone due to periodontitis. Case Presentation: A 57-year-old woman with root fractures in maxillary bilateral central incisors, periodontitis, and malocclusion was treated with connecting implants and natural teeth. Bone levels surrounding maxillary bilateral lateral incisors were diminished due to root fractures in adjacent central incisors and periodontitis. After initial periodontal therapy, hopeless maxillary central incisors were extracted, replaced with implants using a digitally simulated surgical guide, and guided bone regeneration and connective tissue grafting were performed. Implants were connected to lateral incisors with provisional restorations, and orthodontic treatment was initiated following digital set-ups incorporating implants into the overall strategy. Final porcelain-fused-to-zirconia restorations were placed after orthodontic treatment. At the 5-year follow-up, gingival morphology, coloration, and position of lateral incisors remained stable. Conclusions: This case demonstrates that connecting implants to natural teeth in the anterior region can effectively maintain periodontal tissues around natural teeth and allow for minimally invasive, short-term, and esthetic treatment. However, careful long-term observation through maintenance is necessary due to limited evidence for this approach in the anterior region. Full article

Odontogenic sinusitis is a type of sinusitis caused by apical lesions of teeth near the maxillary sinus floor. Its clinical symptoms are highly like other types of sinusitis, often leading to misdiagnosis as general sinusitis by dentists in the early stages. This misdiagnosis delays treatment and may be accompanied by toothache. Therefore, using artificial intelligence to assist dentists in accurately diagnosing odontogenic sinusitis is crucial. This study introduces an innovative odontogenic sinusitis image processing technique, which is fused with common contrast limited adaptive histogram equalization, Min-Max normalization, and the RGB mapping method. Moreover, this study combined various deep learning models to enhance diagnostic accuracy. The YOLO 11n model was used to detect odontogenic sinusitis single tooth position in dental panoramic radiographs and achieved an accuracy of 98.2%. The YOLOv8n-cls model diagnosed odontogenic sinusitis with a final classification accuracy of 96.1%, achieving a 16.9% improvement over non-enhanced methods and outperforming recent studies by at least 4%. Additionally, in clinical applications, the classification accuracy for non-odontogenic sinusitis was 95.8%, while for odontogenic sinusitis it was 97.6%. The detection method developed in this study effectively reduces the radiation dose patients receive during CT imaging and serves as an auxiliary system, providing dentists with reliable support for the precise diagnosis of odontogenic sinusitis. Full article

This paper studies the relevance of CWT (continuous wavelet transform) processing of vibration signals for improving the performance of CNN-based models that detect certain types of helical gearbox faults. Gear tooth damages, such as incipient and localized pitting and localized wear on helical pinion tooth flanks, combined with improper lubrication, are the faults under observation. Vibrations at the housing level for three rotating velocities of the AC motor and three load levels (for each velocity) are acquired with a triaxial accelerometer. Through CWT, the vibration signal is decomposed into 2D time-frequency grayscale images, with a filter bank of ten voices per octave in the frequency band of interest. Three 2D-CNN-based models trained on the CWT-based representation of the vibration signals measured on individual accelerometer axes (X, Y, and Z) are proposed to detect the four health states (one normal and three faulty) of the helical gearbox, regardless of the selected load level or speed on the test rig. These models achieve an accuracy higher than 99%. By fusing the CWT-based representations of the signals on individual axes for use as input to a 2D-CNN, the best-performing model for the proposed defect detection task is generated, reaching an accuracy of 99.91%. Full article

In this study, an experimental analysis of the thermal behavior and wear of polymer and hybrid polymer gears produced with the Fused Deposition Modeling (FDM) method was performed. Compared to conventional polymer gear manufacturing methods, the FDM process represents an energy-efficient material forming method. The low thermal conductivity of polymer gears has an impact on heating, which limits their application. The novelty of this research is an experimental analysis on hybrid polymer gears, and, for this purpose, a new hybrid polymer gear design with aluminum and steel inserts has been proposed. An in-house-developed non-mechanically closed-loop test rig was used to investigate Polyamide (PA) gears under different loads. An accelerated step load test procedure was employed, while the gears’ bulk temperature was recorded with a thermal imaging camera. The print quality affected the tooth flank surface roughness, so polymer gears with two different print qualities were initially produced. Hybrid polymer gears were produced with a higher print quality, since the print quality had an influence on the heating and wear. The correlation between the bulk temperature and wear was observed for all of the tested gears. A novel design of hybrid polymer gears with aluminum inserts achieved up to a 9 °C (17%) lower bulk temperature and a higher wear resistance. Full article

Choosing an appropriate prosthetic material for the superstructure of an implant-supported or tooth-implant supported fixed partial denture (FPD) is crucial for the success of the prostheses. The objective of this study was to examine the effect of prosthetic material type and tooth-to-implant support on stress distribution of FPDs using three-dimensional finite element analysis (3D FEA). Two FEA models were generated, distinguished by their support configurations: Model I representing an FPD supported by implants, and Model II depicting an FPD supported by both a tooth and an implant. Two different restorative materials, porcelain-fused-to-metal (PFM) and monolithic zirconia, were evaluated for stress distribution under axial and oblique loads of 300 N applied to the pontic. Under both axial and oblique loading conditions, the maximum von Mises stress values were observed to be higher in the implant-abutment complex of both zirconia implant-supported and tooth-implant-supported FPDs compared to PFM FPDs. In the case of axial loading, comparable stress values were found in the cortical bone for PFM (12.65 MPa) and zirconia implant-supported FPDs (12.71 MPa). The zirconia tooth-implant-supported FPD exhibited the highest stress values in the implant-abutment system. Full article

Accurate tooth segmentation and numbering are the cornerstones of efficient automatic dental diagnosis and treatment. In this paper, a multitask learning architecture has been proposed for accurate tooth segmentation and numbering in panoramic X-ray images. A graph convolution network was applied for the automatic annotation of the target region, a modified convolutional neural network-based detection subnetwork (DSN) was used for tooth recognition and boundary regression, and an effective region segmentation subnetwork (RSSN) was used for region segmentation. The features extracted using RSSN and DSN were fused to optimize the quality of boundary regression, which provided impressive results for multiple evaluation metrics. Specifically, the proposed framework achieved a top F1 score of 0.9849, a top Dice metric score of 0.9629, and an mAP (IOU = 0.5) score of 0.9810. This framework holds great promise for enhancing the clinical efficiency of dentists in tooth segmentation and numbering tasks. Full article

Background: The distinction between where the pulp chamber ends and the root canal system begins is poorly defined within the existing literature. Methods: This paper aimed to describe a range of accurate methods to define the transition from pulp chamber to root canal in different first molar root morphologies using micro-focus computed tomography (micro-CT). Methods: The sample consisted of 86 mandibular and 101 maxillary first molars from the skeletal collections housed in the Department of Anatomy and Histology of the Sefako Makgatho Health Sciences University and the Pretoria Bone Collection. A stepwise approach using the cemento–enamel junction (CEJ) and dedicated landmarks was followed to create an automated cross-sectional slice. Results: Transition from pulp chamber to root canal could be accurately determined on maxillary and mandibular teeth. The occurrence of two separate roots in mandibular molars was 97.7%, with the remaining 2.3% having an additional disto-lingual root, with no mandibular molars displaying fused roots. In the maxillary molars, 92.1% had three separate roots and 7.9% displayed root fusion. Within this group, one tooth displayed a C-shaped root canal configuration and one a mesotaurodont-type morphology. Conclusion: The suggested methodology to determine orifice location was found to be appropriate in all morphological types. Full article

Tooth fusion is a dental anomaly with a prevalence of 0.1% in permanent dentition. The aim of this paper is to present the occurrence, region of fusion, and prognosis of fused tooth which is a very rare case in the literature. The authors present a very rare case with a maxillary right lateral incisor fused to a supernumerary tooth on the palatal side. The eruption was delayed, but eruption occurred naturally at 9 years and 6 months. However, cone-beam computed tomography at 11 years and 6 months revealed it was diagnosed as a fused tooth. The authors undertook a literature review over the past 10 years and found 30 articles about fused teeth between permanent teeth and supernumerary teeth. It was more common in males than females and there were no differences depending on the occurrence. Mesiodistal fusion was more common in the incisor region, while labiopalatal fusion was more common in the molar region. Most cases required dental treatment with a surgical approach, root canal treatment, or orthodontic treatment. The present study highlights the importance of long-term follow-up and suggests the region of fusion and prognosis of the fused tooth may vary depending on the occurrence. Full article

The purpose of this study is to evaluate the mechanical properties and clinical fitness of 3D-printed bioglass porcelain fused to metal (PFM) dental crowns. To evaluate the mechanical properties, tensile strength, Vickers microhardness, shear bond strength, and surface roughness tests of the SLM printed Co-Cr alloy was conducted. A right mandibular 1st molar tooth was prepared for a single dental crown (n = 10). For a three-unit metal crown and bridge, the right mandibular first premolar and first molar were prepared. Bioglass porcelain was fired to fabricate PFM dental restorations. A clinical gap was observed and measured during each of the four times porcelain was fired. A statistical analysis was conducted. The SLM technique showed the largest statistically significant tensile strength and a 0.2% yield strength value. The milling technique had the lowest statistically significant compressive strength value. The shear bond strength and surface roughness showed no statistically significant difference between the fabricated method. There was a statistically significant change in marginal discrepancy according to the porcelain firing step. The casting technique showed the greatest statistically significant margin discrepancy value. The SLM method showed better fitness than the traditional casting method and showed better mechanical properties as a dental material. Full article

The Keratinocyte differentiation factor 1 (KDF1) is reported to take part in tooth formation in humans, but the dental phenotype of Kdf1 mutant mice has not been understood. Additionally, the role of the KDF1 gene in dental hard tissue development is rarely known. In this study, we constructed a Kdf1 missense mutation knock-in mouse model through CRISPR/Cas9 gene-editing technology. Enamel samples from wildtypes (WT) and Kdf1 homozygous mutants (HO) were examined using micro-computed tomography (micro-CT), scanning electron microscopy (SEM), an atomic force microscope (AFM) and Raman microspectroscopy. The results showed that a novel Kdf1 missense mutation (c. 908G>C, p.R303P) knock-in mice model was constructed successfully. The enamel of HO mice incisors appeared chalky and defective, exposing the rough interior of the inner enamel and dentin. Micro-CT showed that HO mice had lower volume and mineral density in their tooth enamel. In addition, declined thickness was found in the unerupted enamel layer of incisors in the HO mice. Using SEM and AFM, it was found that enamel prisms in HO mice enamel were abnormally and variously shaped with loose decussating crystal arrangement, meanwhile the enamel rods were partially fused and collapsed, accompanied by large gaps. Furthermore, misshapen nanofibrous apatites were disorderly combined with each other. Raman microspectroscopy revealed a compromised degree of order within the crystals in the enamel after the Kdf1 mutation. To conclude, we identified enamel structure defects in the Kdf1 missense mutation knock-in mice, which displayed fragmentary appearance, abnormally shaped prism structure, decreased mineral density, altered crystal ordering degree and chemical composition of the enamel layer. This may support the potential role of the KDF1 gene in the natural development of enamel. Full article

In the last few decades Additive Manufacturing has advanced and is becoming important for biomedical applications. In this study we look at a variety of biomedical devices including, bone implants, tooth implants, osteochondral tissue repair patches, general tissue repair patches, nerve guidance conduits (NGCs) and coronary artery stents to which fused deposition modelling (FDM) can be applied. We have proposed CAD designs for these devices and employed a cost-effective 3D printer to fabricate proof-of-concept prototypes. We highlight issues with current CAD design and slicing and suggest optimisations of more complex designs targeted towards biomedical applications. We demonstrate the ability to print patient specific implants from real CT scans and reconstruct missing structures by means of mirroring and mesh mixing. A blend of Polyhydroxyalkanoates (PHAs), a family of biocompatible and bioresorbable natural polymers and Poly(L-lactic acid) (PLLA), a known bioresorbable medical polymer is used. Our characterisation of the PLA/PHA filament suggest that its tensile properties might be useful to applications such as stents, NGCs, and bone scaffolds. In addition to this, the proof-of-concept work for other applications shows that FDM is very useful for a large variety of other soft tissue applications, however other more elastomeric MCL-PHAs need to be used. Full article

The dental anomaly fused teeth is defined as the union of two or more teeth. Its aetiology is unclear; to date no studies have investigated its genetic background. Therefore, this study, on the basis of a hypothesised genetic component, investigated the genetic background of patients with fused teeth using whole exome sequencing. Fifteen individuals from six families, including members with and without fused teeth, provided saliva samples that were analysed using whole exome sequencing. Patients with other congenital diseases were excluded from this study. Rare variants were extracted from the sequencing data and filtered by family grouping to identify candidate variants. As a result, ERCC6, OBSCN, SLC27A3, and KIF25 were identified as candidate variants. Our sequencing analysis identified four candidate gene variants associated with fused teeth, which now require further investigation. A genetic basis for the anomaly appears likely. This may assist in understanding the aetiology of fused teeth, which in turn supports better oral care and treatment, as well as future regenerative medicine and gene therapy. Full article

Tooth anomalies in childhood may negatively affect the healthy development of the dentition and occlusion; hence, it is important to examine the actual oral condition at an early stage. The present study was performed to understand the state of missing deciduous anterior teeth in children aged 3.5 years who underwent dental checkups in Matsubara City. In total, 3508 children received oral examinations, and items such as erupted deciduous teeth and teeth anomalies were recorded. Among these children, those with missing anterior deciduous teeth were selected, and their details were analyzed. In the 216 children, there were 266 missing anterior deciduous teeth. Congenitally missing anterior deciduous teeth were observed in 80 children, and fused teeth were observed in 128 children. The missing teeth were predominantly located in the mandible and occurred more frequently on the right side. The most common reason for acquired missing teeth was trauma, and no cases of spontaneous loss due to systemic disease were found in this study. Screening for various tooth anomalies is expected to play an important role in cultivating a better understanding of the oral cavity of children, developing healthy dentitions, and contributing to the early detection of some systemic diseases. Full article

The studies conducted so far indicate a negative effect of dioxins on the structure of the alveolar bone and teeth, especially in the developmental period in rats. The research aimed to analyze the indirect effect of dioxins contained in the body of female rats on the structure of the dental organ in their offspring in the neonatal period and to determine the possibility of reducing potential dioxin disorders of the structure of hard tissues in the offspring of intoxicated mothers by simultaneous administration of vitamin E or acetylsalicylic acid (ASA). Another goal of the research was to determine the level of magnesium, calcium and phosphorus contained in bone tissue as indicators of the mineralization process of hard tissues in rats, in the case of using 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and acetylsalicylic acid or α-tocopherol. The experiment was carried out on eight female rats of the Buffalo strain divided into four groups. From the offspring of eight females, the mandibles were removed from the mandibular joints, and then, after the removal of soft tissues, they were prepared for individual tests. Selected morphological, chemical and physical parameters of the teeth of the offspring of female rats from the experimental groups were analyzed. The analysis showed the effect of vitamin E and ASA on the content of Mg, Ca and P. In combination with TCDD, vitamin E and ASA, they positively inhibit the inflammatory process, preventing the leaching of Ca and Mg from the bones. ASA counteracted this phenomenon much more effectively than vitamin E. Detailed analysis of the tooth morphology showed that the molars’ crowns exhibit shape disturbances under the influence of TCDD. Individual nodules in teeth T1, T2, T3 did not fuse, and the roots showed signs of hypertrophy. The study confirmed the negative effect of TCDD on tooth development. Teeth arising early in development are the most sensitive to the disorders, while the later ones are less exposed to the toxic effects of TCDD transmitted by the mother. Full article