Primary tumors of the submandibular glands: a retrospective study based on 41 cases

We report our experience on the diagnostic approach, treatment, and follow-up of primary submandibular gland tumors. Retrospective review. Tertiary referral center. Forty-one adult patients, 22 male and 19 female, with primary submandibular gland tumors, 20 benign and 21 malignant. Age, gender, clinical findings, cyto- and histopathology, treatment and outcome were analyzed. Most tumors presented as a painless submandibular mass. Thirty three patients underwent a fine needle aspiration, the sensitivity, specificity and accuracy of which--in detecting malignant tumors--were 79%, 100% and 88%, respectively. Preoperative radiological imaging was performed in 30 cases. Patients with benign tumors were treated with surgery. Most malignant tumors were treated with a combined modality, including neck dissection and radiation therapy. Five patients developed a postoperative complication. Recurrent disease was encountered in 5 malignant tumors. The 2, 5 and 10 year disease-specific survival of patients with malignancy were 84%, 75% and 41%, respectively. The preoperative assessment of the nature of submandibular gland tumors remains challenging. Aggressive treatment of patients with malignant disease may help to avoid poor prognosis.

Proliferation, differentiation and gene expression of osteoblasts in boron-containing associated with dexamethasone deliver from mesoporous bioactive glass scaffolds

Boron is one of the trace elements in the human body which plays an important role in bone growth. Porous mesopore bioactive glass (MBG) scaffolds are proposed as potential bone regeneration materials due to their excellent bioactivity and drug-delivery ability. The aims of the present study were to develop boron-containing MBG (B-MBG) scaffolds by sol-gel method and to evaluate the effect of boron on the physiochemistry of B-MBG scaffolds and the response of osteoblasts to these scaffolds. Furthermore, the effect of dexamethasone (DEX) delivery in B-MBG scaffold system was investigated on the proliferation, differentiation and bone-related gene expression of osteoblasts. The composition, microstructure and mesopore properties (specific surface area, nano-pore volume and nano-pore distribution) of B-MBG scaffolds have been characterized. The effect of boron contents and large-pore porosity on the loading and release of DEX in B-MBG scaffolds were also investigated. The results have shown that the incorporation of boron into MBG scaffolds slightly decreases the specific surface area and pore volume, but maintains well-ordered mesopore structure and high surface area and nano-pore volume compared to non-mesopore bioactive glass. Boron contents in MBG scaffolds did not influence the nano-pore size distribution or the loading and release of DEX. B-MBG scaffolds have the ability to maintain a sustained release of DEX in a long-term span. Incorporating boron into MBG glass scaffolds led to a controllable release of boron ions and significantly improved the proliferation and bone-related gene expression (Col I and Runx2) of osteoblasts. Furthermore, the sustained release of DEX from B-MBG scaffolds significantly enhanced alkaline phosphatase (ALP) activity and gene expressions (Col I, Runx2, ALP and BSP) of osteoblasts. These results suggest that boron plays an important role in enhancing osteoblast proliferation in B-MBG scaffold system and DEX-loaded B-MBG scaffolds show great potential as a release system to enhance osteogenic property for bone tissue engineering application.

Multiscale Characterization of Acrylic Bone Cement Modified with Functionalized Mesoporous Silica Nanoparticles

Acrylic bone cement is widely used to anchor orthopedic implants to bone and mechanical failure of the cement mantle surrounding an implant can contribute to aseptic loosening. In an effort to enhance the mechanical properties of bone cement, a variety of nanoparticles and fibers can be incorporated into the cement matrix. Mesoporous silica nanoparticles (MSNs) are a class of particles that display high potential for use as reinforcement within bone cement. Therefore, the purpose of this study was to quantify the impact of modifying an acrylic cement with various low-loadings of mesoporous silica. Three types of MSNs (one plain variety and two modified with functional groups) at two loading ratios (0.1 and 0.2 wt/wt) were incorporated into a commercially available bone cement. The mechanical properties were characterized using four-point bending, microindentation and nanoindentation (static, stress relaxation, and creep) while material properties were assessed through dynamic mechanical analysis, differential scanning calorimetry, thermogravimetric analysis, FTIR spectroscopy, and scanning electron microscopy. Four-point flexural testing and nanoindentation revealed minimal impact on the properties of the cements, except for several changes in the nano-level static mechanical properties. Conversely, microindentation testing demonstrated that the addition of MSNs significantly increased the microhardness. The stress relaxation and creep properties of the cements measured with nanoindentation displayed no effect resulting from the addition of MSNs. The measured material properties were consistent among all cements. Analysis of scanning electron micrographs images revealed that surface functionalization enhanced particle dispersion within the cement matrix and resulted in fewer particle agglomerates. These results suggest that the loading ratios of mesoporous silica used in this study were not an effective reinforcement material. Future work should be conducted to determine the impact of higher MSN loading ratios and alternative functional groups. (C) 2014 Elsevier Ltd. All rights reserved.

Long-term stability of contour augmentation with early implant placement following single tooth extraction in the esthetic zone: a prospective, cross-sectional study in 41 patients with a 5- to 9-year follow-up

BACKGROUND Early implant placement with simultaneous contour augmentation is documented with short- and medium-term studies. The long-term stability of contour augmentation is uncertain. METHODS In this prospective, cross-sectional study, 41 patients with an implant-borne single crown were examined twice, in 2006 and 2010. Clinical, radiologic, and esthetic parameters were assessed at both examinations. In addition, a cone beam computed tomographic (CBCT) image was obtained during the second examination to assess the dimensions of the facial bone wall. RESULTS All 41 implants demonstrated ankylotic stability without signs of peri-implant infection at both examinations. The clinical parameters remained stable over time. Satisfactory esthetic outcomes were noted, as assessed by the pink and white esthetic score (PES/WES) indices. Overall, the PES scores were slightly higher than the WES scores. None of the implants developed mucosal recession over time, as confirmed by values of the distance between implant shoulder and mucosal margin and cast measurements. The periapical radiographs yielded stable peri-implant bone levels, with a mean distance between implant shoulder and first visible bone-implant contact value of 2.18 mm. The CBCT analysis demonstrated a mean thickness of the facial bone wall ≈2.2 mm. In two implants (4.9%) no facial bone wall was detectable radiographically. CONCLUSIONS This prospective cross-sectional study demonstrates stable peri-implant hard and soft tissues for all 41 implants examined and satisfactory esthetic outcomes overall. The follow-up of 5 to 9 years confirmed again that the risk for mucosal recession is low with early implant placement. In addition, contour augmentation with guided bone regeneration was able to establish and maintain a facial bone wall in 95% of patients.