Differentiation malignant from benign parotid tumors in children with diffusion-weighted MR imaging

Purpose

To differentiate pediatric solid malignant from the benign parotid tumors with diffusion-weighted MR imaging (DWI).

Materials and methods

A retrospective study comprising 38 children with parotid tumors (21 boys and 17 girls aged from 2 months to 17 years) was conducted using (DWI) of the parotid gland. Apparent diffusion coefficient (ADC) maps were generated. The ADC value of the parotid tumors was calculated.

Results

The mean ADC value of malignant parotid tumors (1.08?±?0.1, 1.04?±?0.1?×?10^?3mm²/s) was significantly lower [P?=?0.001] than that of benign lesions (1.69?±?0.2, 1.72?±?0.3?×?10^?3mm²/s). A threshold of ADC of 1.40, 1.33?×?10^?3mm²/s was used for differentiating malignant parotid tumors from benign lesions and led to the best results of the area under the curve of 0.940, 0.929, accuracy of 86, 89%, sensitivity of 94, 94%, specificity of 80, 85%, negative predictive value of 94.1, 94.4%, and positive predictive value of 81, 85%. There was insignificant difference in ADC values of malignant lesions (P?=?0.23, 0.30) as well as within benign lesions (P?=?0.25, 0.08).

Conclusion

DWI is an innovative anticipating imaging technique that can be used in the differentiation of pediatric solid malignant parotid tumors from benign lesions.

     

Diffusion-weighted imaging with histogram analysis of the apparent diffusion coefficient maps in the diagnosis of parotid tumours

The aim of this study was to investigate the role of diffusion-weighted imaging (DWI) with histogram analysis of apparent diffusion coefficient (ADC) maps in the characterization of parotid tumours. This prospective study included 39 patients with parotid tumours. All patients underwent magnetic resonance imaging with DWI, and ADC maps were generated. The whole lesion was selected to obtain histogram-related parameters, including the mean (ADC_mean), minimum (ADC_min), maximum (ADC_max), skewness, and kurtosis of the ADC. The final diagnosis included pleomorphic adenoma (PA; n = 18), Warthin tumour (WT; n = 12), and salivary gland malignancy (SGM; n = 9). ADC_mean (×10^?3 mm²/s) was 1.93 ± 0.34 for PA, 1.01 ± 0.11 for WT, and 1.26 ± 0.54 for SGM. There was a significant difference in whole lesion ADC_mean among the three study groups. Skewness had the best diagnostic performance in differentiating PA from WT (P = 0.001; best detected cut-off 0.41, area under the curve (AUC) 0.990) and in discriminating WT from SGM (P = 0.03; best detected cut-off 0.74, AUC 0.806). The whole lesion ADC_mean value had best diagnostic performance in differentiating PA from SGM (P = 0.007; best detected cut-off 1.16 × 10^?3 mm²/s, AUC 0.948). In conclusion, histogram analysis of ADC maps may offer added value in the differentiation of parotid tumours.     

Extracapsular spread and FDG PET/CT correlations in oral squamous cell carcinoma

The purpose of this study was to evaluate the use of ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) to identify extracapsular spread (ECS) with histologic correlations in oral squamous cell carcinoma (OSCC). The medical records of 80 patients who underwent of FDG PET/CT for OSCC before surgery were reviewed. ECS was present in 60% (24/40) dissected necks and in 55% (39/71) of dissected cervical levels. A significant difference was found between the maximum standardized uptake (SUV_max) values of cervical lymph nodes with ECS and without ECS (3.33 ± 1.91 vs. 1.12 ± 1.24, p < 0.001). When receiver operating characteristic (ROC) curve analysis and SUV_max values were used to detect ECS, the area under the ROC curve was 0.864 ± 0.045 (p < 0.001). At an optimal SUV_max cut-off value of 2.25 the sensitivity and specificity were 85% and 88%, respectively. The presence of ECS and a SUV_max > 2.25 had a significant adverse effect on 5-year disease specific survival. A SUV_max > 2.25 was found to be associated with a greater risk of cervical lymph node metastasis in OSCC.     

Preoperative and postoperative assessment of temporal and masseter muscle size with magnetic resonance imaging in patients undergoing unilateral temporomandibular joint surgery

The aim of this study was to assess any change between the preoperative and postoperative sizes of temporal and masseter muscles with magnetic resonance imaging (MRI) in patients undergoing unilateral temporomandibular joint surgery.This study was designed and implemented retrospectively. For clinical evaluation, a visual analog scale (VAS) and maximum mouth opening (MMO) were used. In order to make a preoperative diagnosis and perform a 6-month control, muscle size was measured in millimeters (mm) on T1 axial sections in MRI. Statistical analyses were performed using the SPSS 23.0 software package. Numeric variables were compared between two dependent groups using the Wilcoxon signed rank test. Statistical significance was set at p < 0.05.Twelve patients who underwent unilateral discectomy plus dermis-fat grafting, with classical preauricular inverse L incision, were included in the study, and data for eleven female patients were evaluated. The difference in size between the operated and non-operated sides was found to be statistically insignificant at the preoperative stage for both masseter muscle (operated side m^M: 13.264 ± 1.822 mm; non-operated side m^M: 13.264 ± 2.315 mm; p^M = 0.929) and temporal muscle (operated side m^T: 20.345 ± 2.609 mm; non-operated side m^T: 20.582 ± 2.366 mm; p^T = 0.594). There was a significant size reduction in the masseter muscle on the operated side in the postoperative period (preop m^M: 13.264 ± 1.822 mm; postop m^M: 12.036 ± 1.728 mm; p^M = 0.018). Although there was also a size reduction in the operated side of the temporal muscle in the postoperative period, that difference did not reach statistical significance (preop m^T: 20.345 ± 2.609 mm; postop m^T: 19.445 ± 1.603 mm; p^T = 0.182). On the non-operated side, there were no significant postoperative changes in the sizes of either the masseter muscle (preop m^M: 13.264 ± 2.315 mm; postop m^M: 12.682 ± 2.059 mm; p^M = 0.248) or the temporal muscle (preop m^T: 20.582 ± 2.366; postop m^T: 19.891 ± 3.487 mm; p^T = 0.625).Considering the study findings as a whole, a size reduction was observed in the operated side of the masseter muscle after TMJ surgery. The etiology of this change may be surgical trauma to the temporal and masseter muscles, skeletal alteration resulting from condylar change secondary to discectomy, and patients restraining themselves from application of maximum bite force as a result of a self-protection mechanism due to postoperative pain.     

Effects of Calcitonin,Calcitonin Gene-Related Peptide,Human Recombinant Bone Morphogenetic Protein-2, and Parathyroid Hormone–Related Protein on Endodontically Treated Ferret Canines

IntroductionThe purpose of this study was to determine whether human recombinant bone morphogenetic protein-2 (rhBMP-2), calcitonin gene-related peptide (CGRP), calcitonin (CT), or parathyroid hormone–related protein (PTHrP) promoted reparative tertiary dentin or osteodentin formation in ferret canines.MethodsFerrets had up to 4 pulpotomies performed under anesthesia. All pulps had sterile absorbable sponge of a standard size placed in contact with the pulp. The sponge contained sterile saline, rhBMP-2, CGRP, CT, or PTHrP. The opening was filled with an intermediate restorative material. After 6 weeks, the ferrets were anesthetized, and the pulpotomized teeth were extracted. The canines were fixed, decalcified, sectioned, and stained with hematoxylin-eosin. Sections were selected from the area of the opening, and the amount of reparative tertiary dentin and osteodentin was measured by using a digitizer.ResultsAnalysis of the photomicrographs showed that rhBMP-2 induced 0.58 ± 0.19 mm² osteodentin and 0.56 ± 0.18 mm² tertiary dentin. CGRP induced 0.46 ± 0.05 mm² osteodentin and 0.38 ± 0.04 mm² tertiary dentin. The amount of rhBMP-2–induced and CGRP-induced osteodentin and tertiary dentin was significantly (P < .001) more than that found in the sterile saline–treated teeth (0.29 ± 0.03 mm² osteodentin and 0.14 ± 0.03 mm² tertiary dentin) or CT (0.2 ± 0.06 mm² osteodentin and 0.16 ± 0.05 mm² tertiary dentin; P < .01). PTHrP significantly (P < .05) reduced the amount of osteodentin (0.17 ± 0.02 mm²) observed in the saline-treated teeth but was not significantly different in the amount of tertiary dentin observed.ConclusionsRhBMP-2 and CGRP promoted more pulpal healing than either CT or PTHrP.     

Efficacy of tissue engineered bone grafts containing mesenchymal stromal cells for cleft alveolar osteoplasty in a rat model

The development of sufficient tissue engineered bone grafts for alveolar cleft osteoplasty could reduce the necessity of autogenous bone grafts and its donor site morbidity. The aim of the study was to evaluate tissue engineered bone grafts in an artificially created bone defect.Bone grafts were created in vitro colonizing a synthetic hydroxyapatite–tricalciumphosphate scaffold (BONITmatrix^®) with either undifferentiated mesenchymal stromal cells (group 1) or osteogenic differentiated mesenchymal stromal cells (group 2). Cells were multiplied from bone marrow of donor rats. Unmodified scaffolds (group 3) and the tissue engineered bone grafts were inserted into artificial maxillary defects of 54 Lewis rats. In 18 animals the defects remained unfilled (control). After one, three and six weeks the rats were sacrificed. The defect was evaluated radiologically and histologically with regard to the remaining defect volume and diameter. Statistical analysis followed.The bone grafts led to a specific bone formation at the defect margin. No complete reunion of any defect was observed within the healing time. After six weeks, the remaining defect volume was 6.86 ± 3.21 mm³ (control), 4.08 ± 1.36 mm³ (group 1), 5.00 ± 0.84 mm³ (group 2) 5.50 ± 1.05 mm³ (group 3). The remaining defect diameter measured 2.63 ± 0.52 mm (control), 2.39 ± 0.23 mm (group 1), 2.53 ± 0.22 mm (group 2) and 2.70 ± 0.66 mm (group 3). In all experimental groups the defect volume and diameter decreased over time, which was significant for group 1 (p = 0.014), group 2 (p = 0.025) and group 3 (p = 0.048). The defect volume and width was significantly reduced for bone grafts containing undifferentiated cells compared to control (p = 0.035) or scaffolds only (p = 0.05).ConclusionTissue engineered bone grafts induce a pronounced bone formation in artificial bone defects compared to unfilled controls or scaffolds only.     

Three-dimensional analysis of condylar remodeling and skeletal relapse following LeFort-I osteotomy: A one-year follow-up bicenter study

The aim of the study was to quantify the postoperative condylar remodeling after Le Fort I surgery.Patients treated with a Le Fort I osteotomy were investigated. CBCT scans were acquired preoperatively, one week and one year postoperatively. A preoperative 3D cephalometric analysis was performed on the preoperative CBCT. Surgical movements were quantified using a voxel-registration based method (OrthoGnaticAnalyser). After rendering of the condyles from the CBCT, a volumetric analysis was performed. The correlation between the surgical movement of the maxilla and the postoperative condylar volume changes was determined with analysis of variance.ResultsA total of 45 subjects were included in this study. 47 of 90 condyles (52%) showed a mean volume reduction of 93 mm³ (4.9 volume-%) postoperatively. The maxilla was impacted in 12 patients (2.44 ± 2.49 mm) and extruded in 33 patients (1.78 ± 1.29 mm). The maxillary impaction group showed a volume reduction of 50 ± 122 mm³ and the extrusion group showed a mean volume gain of 21 ± 139 mm³ (p = 0.028).ConclusionClinicians should be aware of potential condylar remodeling following solitary Le Fort I osteotomies, particularly in female patients with maxillary impaction.     

Improved inspection of the lateral pharyngeal recess using cone-beam computed tomography in the upright position

Objectives  To evaluate the structure of the lateral pharyngeal recess (LPR) and surrounding structures in computed tomography (CT) images obtained from subjects in the supine and upright positions. Methods  Six subjects were evaluated using cone-beam CT (CBCT) in the upright position, and with a four-row multidetector helical CT (MDCT) in the supine position. All of the voxel sizes were adjusted to 0.3 × 0.3 × 0.3 mm³ in the x, y, z coordinate system. The posterior nasal spine and basion were used as references. The LPR and surrounding structures were measured and compared in the two different modalities. Results  In 83% of the cases, the LPR was deeper when the position was changed from supine to upright. Conclusions  Our results suggest that imaging of the LPR using CBCT with the subject in the upright position is superior to that using MDCT with the subject in the supine position.     

Smad2 overexpression induces alveolar bone loss and up regulates TNF-α, and RANKL

ObjectiveThe aim of the current study was to investigate whether Smad2 overexpression in JE cells induced alveolar bone loss, and to understand the mechanisms regulating the bone loss.MethodsA mouse line was created that used a cytokeratin 14 (K14) promoter to overexpress Smad2 in the epithelium of the transgenic mice (K14-Smad2). Micro CT radiographs (μCT) were used to assess bone loss, bone volume, and bone density. The expression of Tnfα, Il1-β, Ifγ, Rankl, and Opg were assessed by RT-PCR. Western blots were used to detect the protein levels of TNF-α and IL1-β. Tartrate-resistant acid phosphatase (TRAP) was used as a marker for osteoclasts. Wild type (WT) mice were used as controls in all steps of the current study.ResultsK14-Smad2 mice had 52.5% (±4.2) root exposed compared to 32.4%(±3.2) in the WT mice. There was a significant difference in alveolar bone volume in the K14-Smad2 mice when compared to WT mice 2.65 mm³ (±0.3) and 4.3 mm³ (±0.35) respectively. K14-Smad2 mice also had reduced bone density 696.8 mg/cc (±70) at 12 months when compared to WT mice 845.9 mg/cc(±10). The mRNA levels of Tnfα and Rankl increased by 3.26- and 2.5-fold respectively in the K14-Smad2 mice when compared to controls. The protein level of TNF-α was also significantly increased to 2.8-fold in K14-Smad2 mice when compared to WT mice. Smad2 overexpression increased the total numbers of osteoclasts in K14-Smad2 mice (3.4 ± 0.2)-fold when compared to WT mice.ConclusionSmad2 overexpression induces alveolar bone loss and increases the numbers of osteoclasts. Also, Smad2 overexpression up-regulates TNF-α and RANKL.     

Diagnostic accuracy of ultrasound, 18F-FDG-PET/CT,and fused 18F-FDG-PET-MR images with DWI for the detection of cervical lymph node metastases of HNSCC

Objective

This study aimed to compare ¹⁸F-fluorodesoxyglucose positron emission tomography/MRI (¹⁸F-FDG-PET-MRI) fusion images, including diffusion-weighted imaging (DWI), ¹⁸F-FDG-PET/CT, and ultrasound (US) regarding their performance in nodal staging of patients with head and neck squamous cell carcinoma (HNSCC).

Materials and methods

Eighteen patients prospectively underwent ultrasound examination, ¹⁸F-FDG- PET/CT, and MRI before oral tumor resection and bilateral neck dissection. PET data sets were fused with contrast-enhanced T1-weighted MR images. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy for nodal detection were calculated for all the imaging modalities. Furthermore, the accuracy of the correct N-staging was calculated for all methods. Detailed histopathology served as the standard of reference.

Results

The sensitivity, specificity, PPV, NPV, and accuracy for detection of lymph node metastases were 63, 99, 86, 96, and 95 % for ultrasound; 30, 97, 56, 92, and 90 % for ¹⁸F-FDG-PET/CT; 52, 96, 59, 94, and 91 % for ¹⁸F-FDG-PET-MRI; and 53, 97, 67, 95, and 92 % for ¹⁸F-FDG-PET-MRI plus DWI, respectively. There was no significant difference in the diagnostic accuracy for lymph node metastasis detection between ¹⁸F-FDG-PET-MRI and ¹⁸F-FDG-PET/CT (p?=?0.839) and between ¹⁸F-FDG-PET-MRI plus DWI and ¹⁸F-FDG-PET/CT (p?=?0.286), respectively. US was significantly more accurate than ¹⁸F-FDG-PET/CT (p?=?0.009), whereas no significant difference was seen between ¹⁸F-FDG-PET-MRI and US (p?=?0.223) or ¹⁸F-FDG-PET-MRI plus DWI and US (p?=?0.115). The nodal stage was correctly rated by ¹⁸F-FDG-PET-MRI in eight patients, ¹⁸F-FDG-PET-MRI plus DWI in nine patients, US in 12 patients, and ¹⁸F-FDG-PET/CT in five out of 18 patients.

Conclusion

Software-based fusion of ¹⁸F-FDG-PET-MRI and ¹⁸F-FDG-PET-MRI plus DWI may not increase nodal detection and N-staging performance in patients with oral malignancies compared to US and ¹⁸F-FDG-PET/CT.

Clinical relevance

Surgical staging of cervical lymph nodes will not be replaced even by advanced imaging modalities in the near future.     

Clinical course of masticatory function recovery following arthrocentesis in patients with unilateral mandibular condyle head fracture

The aim of this study was to investigate the clinical course of masticatory function recovery following arthrocentesis. Patients with a unilateral condylar head fracture who underwent arthrocentesis for therapeutic reasons were evaluated and compared with patients with a unilateral condylar head fracture who did not undergo arthrocentesis. At 3 months after treatment, the occlusal contact area and maximum bite force in patients with a fracture treated with arthrocentesis were greater than in those who did not receive arthrocentesis at the same time points, although the differences were not significant. Moreover, at 1 and 3 months following arthrocentesis, mean (±SD) occlusal contact area (1 month: 1.99 ± 0.55 mm², p = 0.01; 3 months: 2.90 ± 1.36 mm², p = 0.03) and maximum bite force (1 month: 82.45 ± 15.04 N, p = 0.01; 3 months: 101.11 ± 14.53 N, p = 0.01) on the fractured side in patients who underwent that treatment were significantly reduced when compared with those on the non-fractured side. The authors conclude that if the priority is to avoid open reduction and internal fixation, then the arthrocentesis approach might be a less invasive alternative, albeit with the price of a prolonged healing interval.     

Cotransplantation of mesenchymal stromal cells and endothelial cells on calcium carbonate and hydroxylapatite scaffolds in vivo

This study investigated the cotransplantation of bone marrow mesenchymal stromal cells (BMSC) and human umbilical cord endothelial cells (HUVEC), and evaluated their contribution to vascular and bone tissue engineering in vivo.To evaluate the success of osteogenic differentiation and timely vascularization of different osteoconductive scaffolds in vivo, we transferred BMSC and HUVEC pre-cultivated calcium carbonate (CaCO₃) and hydroxylapatite (HA) matrices into immunocompromised RNU-rats, and analyzed mineralization, expression of osteopontin, and vascular integration via new vessel formation.After in vivo transplantation, pre-cultivated scaffolds demonstrated overall improved mineralization of 44% for CaCO₃ (p = 0.01, SD ± 14.3) and 34% for HA (p = 0.001, SD ± 17.8), as well as improved vascularization of 5.6 vessels/0.1 mm² on CaCO₃ (p < 0.0001, SD ± 2.0) and 5.3 vessels/0.1 mm² on HA (p < 0.0001, SD ± 2.4) compared with non-pre-cultivated controls. However, no significant differences between the implantation of BMSC-only, HUVEC-only, or BMSC + HUVEC cocultures could be observed.There is an increasing demand for improved bone regeneration in tissue engineering. Cotransplantation of mesenchymal stromal cells and endothelial cells often demonstrates synergistic improvements in vitro. However, the benefits or superiority of cotransplantation was not evident in vivo and so will require further investigation.     

Bisphosphonate application and volumetric effects on MRONJ lesions

The purpose of this investigation was to analyze the volume of medication-related osteonecrosis of the jaw (MRONJ) lesions by semi-automatic segmentation of cone-beam computed tomography images, and correlate the results with the underlying diseases and applied medication.MRONJ lesions detected in cone-beam computed tomography images were assessed. The open-source software ITK-Snap enabled volumetric measurements of MRONJ lesions based on semi-automatic segmentation. Results were analyzed according to necrosis volume, localization, and gender. In addition, the underlying disease and the type of application of antiresorptive medication were investigated.Cone-beam computed tomography images of 66 patients were studied. 34 male and 32 female patients were included, with ages ranging from 50 to 93 years at the time of diagnosis. The mean volume was 993.24 ± 620.94 mm³: 484.73 ± 230.97 mm³ for the upper jaw and 1084.04 ± 625.74 mm³ for the lower jaw. The results indicated statistically significant differences between lesions of the upper and lower jaw, regardless of gender (p = 0.003). The analysis of differences between males and females did not show any significant results (p = 0.464), although males presented slightly larger lesions than females. With regard to the underlying disease, patients with osteoporosis presented larger volumes, whereas patients with malignant tumors presented smaller volumes. Nevertheless, no statistically significant differences according to the underlying disease (p = 0.313) were detected. However, patients with intravenous (iv) application showed statistically significantly larger lesions than patients who underwent oral or subcutaneous (s.c.) applications (p = 0.004).It seems that the osteonecrosis volume correlates with the applied antiresorptive agents. Larger MRONJ lesions should be expected in patients who receive intravenous antiresorptive therapy.     

Quantitative assessment of the mandibular bone marrow of diabetes mellitus patients using diffusion-weighted magnetic resonance imaging

Purpose

The purpose of this study was to assess quantitatively the mandibular bone marrow of patients with and without diabetes mellitus (DM) using the apparent diffusion coefficient (ADC) values on diffusion-weighted imaging (DWI).

Methods

65 DM patients (28 men, 37 women, 29–84 years of age, mean age 55.7?±?15.7 years) and age-, sex- and periodontitis stage-matched 65 non-DM patients who had underwent MRI between April 2006 and March 2018 were included in this study. The ADC was calculated using the ADC visualization tool implemented in a dedicated off-line workstation. The regions of interest (ROI) were manually placed on the ADC map on which the mandibular bone marrow from the lower first molar to the lower second molar was observed in patients with and without DM. Statistical analysis was performed using the Mann–Whitney U test and receiver operating characteristic (ROC) curve analysis. P values?<?0.05 were considered statistically significant.

Results

The mean ADC values of the mandibular bone marrow of patients with and without DM were 1.18?±?0.21?×?10^?3 mm²/s and 0.83?±?0.14?×?10^?3 mm²/s, respectively. The ADC values of DM patients were significantly higher than those of patients without DM.

Conclusion

The ADC values allowed the quantitative evaluation of the mandibular bone marrow of DM patients. DWI might serve as a new and noninvasive method to assess the presence of DM.

     

Guided bone regeneration in standardized calvarial defects using beta-tricalcium phosphate and collagen membrane: a real-time in vivo micro-computed tomographic experiment in rats

Guided bone regeneration (GBR) procedures using graft materials have been used for reconstruction of osseous defects. The aim of the present in vivo micro-computed tomographic (µCT) and histologic study was to assess in real time the bone regeneration at GBR sites in standardized experimental calvarial defects (diameter 3.3 mm) using β-tricalcium phosphate (β-TCP) with and without collagen membrane (CM). A single full-thickness calvarial defect was created on the left parietal bone in young female Wistar albino rats (n = 30) weighing approximately 300 g and aged about 6 weeks. The animals were randomly divided into three groups for treatment, based on calvarial defect filling material: (1) control group (n = 10); (2) β-TCP + CM group (n = 10); (3) β-TCP group (n = 10). Real-time in vivo µCT analyses were performed immediately after surgery and at 2, 4, 6 and 10 weeks to determine the volume and mineral density of the newly formed bone (BVNFB, MDNFB) and remaining β-TCP particles (VRBP, MDRBP). The animals were killed at 10 weeks and calvarial specimens were evaluated histologically. In the control group, MDNFB increased significantly at 6 weeks (0.32 ± 0.002 g/mm³, P < 0.01) compared to that at baseline. In β-TCP + CM group, BVNFB (1.10 ± 0.12 mm³, P < 0.01) and MDNFB (0.13 ± 0.02 g/mm³, P < 0.01) significantly increased at the 4th week than baseline. In the β-TCP group, BVNFB (1.13 ± 0.12 mm³, P < 0.01) and MDNFB (0.14 ± 0.01 g/mm³, P < 0.01) significantly increased at 6 weeks compared to that at baseline. Significant reduction in VRBP was neither seen in the β-TCP + CM group nor in the β-TCP group. While in the β-TCP + CM group MDRBP was reduced significantly at 6 weeks (0.44 ± 0.9 g/mm³, P < 0.01) from baseline (0.98 ± 0.03 g/mm³), similar significant reduction in MDRBP from baseline (0.92 ± 0.07 g/mm³) was seen only at 10 weeks (0.45 ± 0.06 g/mm³, P < 0.05) in the β-TCP group. Histologic findings at 10 weeks revealed greater amount of NFB with osteocytes in the matrix, in the β-TCP + CM group than in the β-TCP group. Biomechanical assessment of NFB for hardness (H) and elastic modulus (E) revealed significantly higher values for the β-TCP + CM group (H = 612.6 ± 4.28 Mpa; E = 13.57 ± 0.07 Gpa) when compared to those of the control (H = 192.1 ± 4.93 Mpa; E = 6.76 ± 0.04 Gpa) and the β-TCP groups (H = 241.9 ± 6.29 Mpa; E = 4.34 ± 0.06 Gpa). In conclusion, based on real-time assessment, NFB is formed in calvarial defects as early as 4 weeks following GBR with β-TCP + CM as compared to 6 weeks when β-TCP alone was used.     

Influence of different narrative instructions to record the occlusal contact with silicone registration materials

This study examined the influence of narrative instructions on the occlusal contact area, occlusal contact point and masticatory muscle activities in normal subjects. Twelve healthy men and 12 healthy women with no more than one missing tooth per quadrant participated. Surface EMG was recorded from the masseter and temporal muscle. As a control measurement, intercuspal position was maintained to produce a habitual clenching record (NCR) while the occlusal contact area and occlusal contact point was recorded by means of silicone material. Subsequently, the occlusal contact area was recorded with the narrative instruction for minimum clenching record (MCR), light clenching record (LCR) and strong clenching record (HCR). While the EMG activity (%MVC) increased modestly from MCR to LCR (from 9·3 ± 2·0% to 11·5 ± 1·5%), the occlusal contact area increased rapidly (from 17·2 ± 11·3 mm² to 26·8 ± 15·6 mm²) (P < 0·05). Both EMG activity and occlusal contact area increased gradually from LCR to NCR (to 17·7 ± 2·0% and to 31·4 ± 14·2 mm², respectively). Finally, EMG activity still increased from NCR to HCR (to 44·5 ± 3·7%) (P < 0·05), but the occlusal contact area remained stable (to 36·8 ± 16·6 mm²). Occlusal contact points at left posterior, right posterior, anterior and total area were not significantly different between each task. This study showed that narrative instructions while recording the bite can result in largely stable occlusal contact area. An adequate narrative instruction may therefore contribute to taking a stable occlusal recording in natural dentition.     

The long-term effect of maxillary advancement and impaction on subjective and objective nasal patency: A retrospective case-control study

The aim of this study was to investigate the change of nasal patency after maxillary advancement and impaction (MAX_ADV + IMP) in subjects with skeletal class III malocclusion (cases) and after removal of maxillary cysts in close proximity to the nasal floor in subjects that served as controls. NOSE score, volume derived by computed tomography (VOL), and acoustic rhinometry and rhinomanometry were retrospectively evaluated, before and one year after surgery. The movement of specific landmarks was also measured. NOSE score did not change after surgery, neither in 17 cases (p = 0.10) nor in 17 controls (p = 0.14). In cases, VOL_postop (10088 ± 4200 mm³) was significantly higher than VOL_preop (7807 ± 3721 mm³; p = 0.036). Maxillary advancement and inferior displacement of the ventral maxilla were noted by the movement of incisive foramen in the coronal (3.9 ± 5.4; p = 0.011) and Frankfurt Horizontal plane (2.2 ± 2.0; p = 0.001), respectively. In controls, VOL_postop (9749 ± 3654 mm³) was also significantly higher than VOL_preop (8473 ± 2624 mm³; p = 0.050). Cross-sectional areas, nasal flow and nasal resistance changed significantly after surgery in cases (6/30 pairs; p < 0.018), but not in controls (all p > 0.066). MAX_ADV + IMP increased nasal patency, but did not change the feeling of nasal breathing. Physicians should proceed with caution when informing patients about improvement of nasal breathing after MAX_ADV + IMP.     

Diffusion-weighted magnetic resonance imaging in oral and maxillofacial lesions: preliminary study on diagnostic ability of apparent diffusion coefficient maps

Objectives

The aim of this study was to investigate the usefulness of diffusion-weighted magnetic resonance imaging (DWI) in oral and maxillofacial lesions, especially the utility of apparent diffusion coefficient (ADC) maps for differential diagnosis of these lesions.

Methods

Fifty-seven patients who underwent magnetic resonance imaging for diagnosis of oral and maxillofacial lesions were included in this prospective study. DWI was performed on a 1.5 T unit with b-factors of 0 and 800 s/mm², and ADC maps were generated. ADC values were measured for all 57 oral and maxillofacial lesions (19 squamous cell carcinoma, 10 medication-related osteonecrosis of the jaw, 6 odontogenic abscess, 4 ranula, 4 osteoradionecrosis, 4 hemangioma, 3 pleomorphic adenoma, 3 odontogenic keratocyst, 2 nasopalatine duct cyst, 1 malignant melanoma, and 1 basal cell carcinoma).

Results

The mean ADC values for ranula (2.69 ± 0.59 × 10^?3 mm²/s) and nasopalatine duct cyst (2.34 ± 0.12 × 10^?3 mm²/s) were significantly higher than those for the other oral and maxillofacial lesions (p = 0.000). In contrast, the mean ADC value for odontogenic abscess (0.67 ± 0.36 × 10^?3 mm²/s) was significantly lower than those for the other oral and maxillofacial lesions (p = 0.000).

Conclusions

The present study suggests the usefulness of DWI in oral and maxillofacial lesions, especially the utility of ADC maps for differential diagnosis of these lesions.

     

[18F]FDG-PET/CT improves the detection of synchronous malignancies at primary staging of oral squamous cell carcinoma – A retrospective study

The purpose of this study was to show the non-inferiority of [¹⁸F]FDG-PET/CT compared with panendoscopy with regards to secondary malignancies of the UADT, and to evaluate the diagnostic performance of PET/CT for detecting synchronous malignancies.Patients with newly diagnosed OSCC and both panendoscopy and [¹⁸F]FDG-PET/CT at primary staging were enrolled in this retrospective study. The accuracy in detecting synchronous malignancies was assessed for both modalities, and their diagnostic measures for the detection of malignancies within the UADT were compared. Histopathological analysis and clinical follow-up served as reference standards.In total, 182 patients were enrolled in this study. Eighteen patients (9.9%) had in total 22 synchronous malignancies, of which eight were located within the UADT. [¹⁸F]FDG-PET/CT detected all malignancies within the whole body (sensitivity: 100%) and yielded false-positive results in four cases (specificity: 97.6%). Sensitivity ([¹⁸F]FDG-PET/CT: 100% vs panendoscopy: 87.5%), specificity (99.4% vs 100%), negative predictive value (100% vs 99.4%), and positive predictive value (88.9% vs 100%) for detecting secondary UADT malignancies did not differ between modalities (all p = 0.32).Within the limitations of the study it seems that [¹⁸F]FDG-PET/CT detects synchronous malignancies of the UADT with an accuracy comparable to panendoscopy, and enables highly sensitive whole-body tumor screening in patients with newly diagnosed OSCC. This could be a relevant factor for therapeutic decision making in clinical routine.     

Evaluation of physical properties of fiber-reinforced composite resin

ObjectivesThis study aimed to investigate physical properties of a fiber-reinforced CAD/CAM resin disc, which included woven layers of multi-directional glass fibers.MethodsFiber orientations of CAD/CAM specimens (TRINIA, SHOFU) were specified as longitudinal (L), longitudinal-rotated (LR), and anti-longitudinal (AL). A fiber-reinforced composite (everX posterior, GC (E)) and a conventional composite (Beauti core flow paste, SHOFU (B)) were also tested.A three-point bending test and a tensile test with notchless prism-shaped specimens were conducted using a universal testing machine (AUTOGRAPH AG-IS, Shimadzu). A water absorption test was also carried out after the specimens were stored in water for 24 h or 1 week. Flexural strength and fracture toughness were obtained by conducting a three-point bending test.ResultsTRINIA L and LR groups showed significantly high flexural strength (254.2 ± 22.3 and 248.8 ± 16.7 MPa, respectively). Those were approximately 2.5 times higher than those in AL, E, and B groups (96.8–98.0 MPa) (p < 0.05, ANOVA and Tukey HSD test). No significant difference was shown in flexural modulus among the experimental groups. The fracture toughness in L group (9.1 ± 0.4 MPa/m^1/2) was found to be significantly higher than those in other groups (1.9–3.0 MPa/m^1/2; p < 0.05). TRINIA group demonstrated significantly lower water absorption (4.7 ± 1.9 μg/mm³) than did E (16.1 ± 3.1 μg/mm³) and B (17.3 ± 3.7 μg/mm³) groups (p < 0.05).SignificanceTRINIA demonstrated distinct anisotropy. TRINIA can be used as a superior restorative material when specifying directions of its fiber mesh layers.