European Oral Research最新文献

Purpose: This study aimed to evaluate the impact of ethylenediamine tetra-acetic acid (EDTA), carbohydrate-derived fulvic acid (CHD-FA), and maleic acid (MA) on the flexural strength (FS) and modulus of elasticity (ME) of human radicular dentin.

Materials and methods: Fifteen freshly extracted human mandibular premolars with single roots and single canals were selected. The teeth were decoronated 2 mm below the cementoenamel junction (CEJ), and the roots were sectioned into buccal and lingual halves. Each half was used to prepare two standardized plano-parallel dentin bars (7 mm in length × 1 mm in width × 1 mm in height). The samples were then divided into four groups and immersed in their respective irrigating solutions for 5 minutes: saline (control), maleic acid, CHD-FA, and EDTA. Subsequently, FS and ME were evaluated using a three-point bending test.

Results: Both EDTA and maleic acid reduced the FS and ME of radicular dentin. However, the study demonstrated that higher mean values for FS and ME were recorded in the CHD-FA and saline (control) groups compared to the EDTA and maleic acid groups.

Conclusion: CHD-FA is recommended as an endodontic irrigant, as it does not compromise the mechanical properties of radicular dentin, specifically FS and ME.

Purpose: This study evaluates the effects of different force directions on tooth movement in miniscrew-assisted en masse retraction using finite element analysis (FEA).

Materials and methods: A three-dimensional (3D) finite element model was constructed to simulate en masse retraction in sliding mechanics. A retraction force of 200 g was applied from the anterior retraction hook (ARH) to a miniscrew, and force vectors were resolved along the X, Y, and Z axes. Six different configurations were analysed by varying the ARH (5 mm and 8 mm) and miniscrew heights (6 mm, 8 mm, and 12 mm). Displacement values of anterior and posterior teeth were examined to assess movement patterns in mesiodistal, buccopalatal, and vertical directions.

Results: The analysis revealed that increasing the retraction hook length enhanced mesiodistal tipping of anterior teeth, while higher miniscrew placement reduced mesiodistal tipping of posterior teeth. On the buccopalatal plane, anterior teeth exhibited greater palatal movement when the miniscrew height was reduced, whereas an increased retraction hook height intensified palatal tipping of anterior teeth. Posterior teeth displayed more palatal tipping with a low retraction hook, and greater miniscrew height increased posterior palatal tipping when the hook length remained constant. On the vertical plane, a higher retraction hook induced more intrusion in anterior teeth. Additionally, when a low retraction hook was used, an increase in miniscrew height further enhanced anterior intrusion.

Conclusion: The force direction in en masse retraction should be optimized based on the desired movement in vertical, horizontal, and buccopalatal dimensions. According to the FEA findings, the low hook-low miniscrew combination resulted in maximum palatal crown tipping, while a high miniscrew position was beneficial for torque control by reducing palatal tipping. The low hook-high miniscrew configuration generated significant anterior intrusion, making it a suitable strategy for deep bite correction.

Purpose: This study investigated the bone regenerative potential following immediate implant insertion using osseodensifying Densah drills compared to conventional drills.

Materials and methods: Eight adult male mongrel dogs were randomly assigned to three groups using a split-mouth design. Atraumatic extraction of the maxillary second premolar was performed in all dogs, and the sockets of the distal roots served as the control group. Group I was subdivided into two subgroups: in subgroup IA, the mesial socket of the second premolar was drilled using NucleOSS drills, while in subgroup IB, the socket was prepared using osseodensifying Densah drills. The dogs were euthanized immediately after osteotomy preparation. Group II was also subdivided into two subgroups: in subgroup IIA, osteotomy preparation was performed using NucleOSS drills, while in subgroup IIB, the osteotomy was prepared using Densah drills, followed by the insertion of NucleOSS T6 implants in both subgroups. The dogs were euthanized two months after implant insertion. Specimens were stained using Hematoxylin and Eosin as well as Masson Trichrome stain and subjected to histomorphometric analysis. Cone beam computed tomography was used to measure radiographic bone density.

Results: Subgroup IA exhibited areas of thermal osteonecrosis around the drilling site. Subgroup IB showed bone chips compressed into the bone marrow spaces of the osteotomy wall. The bone area percentage and bone density around implants in subgroup IIB were significantly higher than those in subgroup IIA (P<0.05).

Conclusion: Osseodensification is an effective technique for increasing bone density around implants in areas of poor bone quality, which is considered a promising indicator of long-term clinical success.

Purpose: The purpose of this in-vitro study was to evaluate the 3D digital trueness of CAD/CAM custom milled post-and-cores fabricated from three contemporary materials using two different 5-axis milling machines.

Materials and methods: A standardized virtual post-and-core CAD design, augmented with landmarks for the standardization of milling, scanning, and 3D analysis protocols, was imported into the CAM software of two different 5-axis milling machines: the CORiTEC 350i and the InLab MC X5. Custom post-and-cores were fabricated from three distinct materials: zirconia, fiber-glass composite, and polyetheretherketone (PEEK). For each material, 10 post-and-cores were milled on each machine, resulting in a total of 60 custom samples. After milling, these post-and-cores were scanned using a standardized method. The resulting scan meshes were superimposed onto the reference CAD design mesh to evaluate 3D surface deviations. A two-way analysis of variance (ANOVA) was employed to determine the effects of material and milling machine on the trueness of the milled post-and-cores.

Results: No significant interaction between material and milling machine was found (p=0.813). PEEK showed significantly lower deviations (mean of 37.2 μm) compared to zirconia (57.2 μm, p<0.001) and glass-fiber composite (48.8 μm, p=0.017). The 350i produced PEEK post-and-cores with mean deviations of 12.7 μm less than the MC X5 (p=0.03), with no significant differences for other material-machine combinations.

Conclusion: Both milling machines demonstrated high trueness in milling post-and-cores. PEEK outperformed zirconia in trueness. When milled with the CORiTEC 350i, PEEK showed a small improvement in trueness over glass-fiber; however, no significant difference was observed with the InLab MC X5. The CORiTEC 350i excelled in milling PEEK, achieving the least 3D deviation, highlighting the influence of both material and machine on the trueness of milled post-and-cores.

The high-resolution imaging capabilities of Magnetic Resonance Imaging (MRI) make it highly suitable for visualizing a wide range of dentomaxillofacial pathologies, including tumors, inflammatory conditions, and vascular abnormalities. This review focuses to the role of MRI in imaging head and neck pathologies, highlighting its advantages over traditional radiodiagnostics in dentistry. MRI's ability to detect periapical lesions, differentiate between various cysts and tumors, and assess the characteristics of odontogenic and non-odontogenic lesions is discussed. Special consideration is given to the differentiation of odontogenic keratocysts and ameloblastomas, as well as the evaluation of odontogenic fibromas and myxomas using dynamic contrast-enhanced MRI. Additionally, the review explores the potential of diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) values in distinguishing benign from malignant lesions, emphasizing the significance of these techniques in characterizing salivary gland tumors. Future advancements in MRI technology, including the application of high-field MRI and radiomics, are also considered. Radiomics, driven by artificial intelligence, offers a promising approach to extracting quantitative features from medical images, potentially enhancing the accuracy of diagnosis and prognosis in oral cancer. The review concludes by underscoring the transformative impact of MRI in dentomaxillofacial radiodiagnostics, advocating for its broader adoption in clinical practice to improve diagnostic accuracy and patient outcomes.

Purpose: The aim of this study is to compare the accuracy of root resorption volume measurements among three cone-beam computed tomography (CBCT) devices using various imaging parameters.

Materials and methods: A total of 42 external root resorption (ERR) defects were mechanically created on the buccal and palatinal surfaces of the roots of seven extracted human teeth. Volume measurements of the defects were performed using three CBCT devices and six different imaging protocols. CBCT measurements were then compared with those calculated from micro-computed tomography (micro-CT) images.

Results: The mean absolute error values indicated that the rate of measurement accuracies from best to worst was obtained with KaVo 3D eXam (0.125 mm voxel, 0.2 mm voxel, respectively), Orthophos XG 3D (0.1 mm voxel, 0.16 mm voxel, respectively), and Rainbow CT (0.2 mm voxel, 0.3 mm voxel, respectively). No statistically significant difference was found between any of the CBCT measurements in comparison to the micro-CT evaluations.

Conclusion: Although external root resorption is a small object to evaluate using CBCT, larger voxel sizes (e.g., 0.3 mm) of CBCT systems can be employed during scanning without compromising image quality.

Purpose: This study aims to investigate the in vitro fracture loads of three different terminal cantilever forms of implant-supported zirconia frameworks.

Materials and methods: A total of 30 implant-supported zirconia frameworks (Aconia, China) were CAD/CAM-fabricated and divided into three groups, each with a distal abutment cantilever form design of 5mm: Group A had square cantilevers, Group B had oval cantilevers, and Group C had oval-square cantilevers. Universal testing machine was used to apply vertical loads to the samples, and the fracture loads were recorded. Variance analysis and Tukey's post-hoc tests were applied for statistical evaluation.

Results: There was no significant difference between the mean fracture loads of Group B (587.8±112.2 N) and Group C (591.3 ±81.3 N), but both of these groups exhibited significantly lower fracture loads compared to Group A (893.8±145 N, p<0.001 for each).

Conclusion: Within the scope of this experimental study, it can be concluded that implant-supported terminal square shaped cantilever zirconia frameworks, each measuring 5 mm from the distal abutment, are more likely to exhibit greater resistance to vertical loads compared to their oval and oval-square counterparts.

Purpose: Several relatively large series from developed countries have extensively described the demographic and clinical characteristics of oral lichen planus (OLP). However, such descriptions from developing countries are rare. This study aimed to investigate the differences in these aspects within a cohort of Sri Lankan patients affected by OLP.

Materials and methods: Cases diagnosed with OLP between 1999 and 2019 were retrieved. Demographic data, clinical presentation, main complaints, age, sex, lesion sites, and histological information, were collected from the database. Cases with lichenoid reactions and incomplete data were excluded. Instances with multiple biopsies were treated as single cases. Frequencies were compared using chi-square statistics.

Results: The database identified a total of 3734 cases. The male-to-female ratio was 1:1.6, indicating an overall female predominance. The youngest patient reported was 1 year and 2 months old, presenting with brownish pigmentations on the right side of the buccal mucosa. The highest number of cases were observed in the 41-50-year age group, followed by the 51-60-year age group. The most common clinical type was the reticular type, followed by atrophic and erosive types. 200 patients presented with blackish pigmentations in the oral mucosa, experiencing a burning sensation without evidence of the typical reticular background. The plaque type was more common on the dorsal surface of the tongue, showing a statistically significant association (p<0.05). Ninety cases exhibited dysplastic changes ranging from mild to moderate degrees, accounting for 2.4% of the total sample.

Conclusion: While the malignancy rate is not significantly high enough to reduce morbidity and mortality from cancer arising on OLP lesions, regular follow-up and examinations are recommended for early diagnosis of malignant transformation.

Magnetic Resonance Imaging (MRI) has emerged as a pivotal diagnostic tool in dentomaxillofacial radiology, surpassing conventional imaging techniques by offering superior contrast resolution for soft tissue lesions without the use of ionizing radiation. This comprehensive review explores the expanding applications of MRI in dentistry, highlighting its integration into routine diagnostic protocols and its significance in the evaluation of oral and maxillofacial structures. The article delves into the physics of MRI, detailing the various sequences such as Spin Echo (SE), Gradient Echo (GRE), and Short-Tau Inversion Recovery (STIR), each tailored for specific diagnostic needs. Advanced techniques like Dynamic Contrast-Enhanced MRI and Diffusion-Weighted Imaging (DWI) are discussed for their roles in assessing tissue perfusion and differentiating between benign and malignant lesions. The review emphasizes the necessity of appropriate coil selection and parameter optimization to enhance image quality, particularly in dental applications where artifacts from restorative and prosthetic materials can pose challenges. Furthermore, the article addresses the utility of MRI in visualizing dental hard tissues, the temporomandibular joint, and neurovascular structures, providing a comprehensive overview of its diagnostic capabilities. The integration of MRI into global health systems and the role of Personal Electronic Health Records in reducing redundant imaging are also examined. Conclusively, the review underscores the transformative impact of MRI on dentomaxillofacial diagnostics, advocating for its broader adoption in clinical practice to facilitate accurate diagnosis and effective treatment planning.

Purpose: The aim of this study is to compare the biocompatibility of two different resin composites after polymerization under two different light sources in three different time periods.

Materials and methods: 72 polyethylene tubes polymerized with 2 different resin composites and 2 different light sources (Elipar S10 and Valo ) [Group 1: Kalore Elipar S10 (KE), Group 2: Kalore Valo (KV), Group 3: Essentia Elipar S10 (EE), Group 4: Essentia Valo (EV)] were implanted in the dorsal connective tissue of 18 rats. 24 empty polyethylene tubes [Group 5: (Control group)] were implanted in the dorsal connective tissue of 6 rats. Then, the rats were sacrificed after 7th, 15th and 30th days in each time intervals (n=8). Biopsy samples were stained with H&E and examined for inflammation, necrosis, macrophage infiltrate, giant cell and fibrous capsule criteria. Immunohistochemical staining was performed to evaluate proinflammatory cytokines (IL-1β, IL-6 and IL-8).

Results: When the composite groups and the control groups were compared; the difference was statistically significant for the criteria of inflammation at 7th and 15th days, there was no statistical difference between the time points in terms of fibrous capsule and necrosis. When the composite groups and control groups were evaluated in terms of proinflammatory cytokines; statistically significant differences were found at 7th, 15th and 30th days.

Conclusion: All CRs used in this study showed acceptable biocompatibility in the subcutaneous tissues of rats after polymerization with different light sources.