Oral Cancer: An Evaluation of Knowledge and Awareness in Undergraduate Dental Students and the General Public.

PURPOSE: To evaluate the knowledge of signs, symptoms and risk factors associated with oral cancer amongst undergraduate dental students and members of the general public. MATERIALS AND METHODS: This study was open for a period of six months (Jan-June, 2013) to all undergraduate dental students in the 4th and 5th year of the dental science programme and dental patients attending the School of Dentistry, Griffith University, Australia. The survey evaluated the knowledge and awareness of clinical signs and symptoms and risk factors of oral cancers. RESULTS: A total of 100 undergraduate students and 150 patients provided informed consent and participated in this survey study. Both patients and dental students were aware of the importance of early detection of oral cancer. With the exception of smoking and persistent ulceration, this study indicated that the knowledge about oral cancer, its signs, symptoms and risk factors was limited amongst participants. CONCLUSION: This study highlights the need to raise awareness and knowledge pertaining to oral cancer, not only in the general community but also amongst those in the dental field. Specific points of concern were the common intraoral sites for oral cancer, erythroplakia as a risk factor, the synergistic action of smoking and alcohol, and HPV (human papilloma virus) as risk factors for oral cancer.

Differential expression of chemokines, chemokine receptors and proteinases by foreign body giant cells (FBGCs) and osteoclasts.

Osteoclasts and foreign body giant cells (FBGCs) are both derived from the fusion of macropahges. These cells are seen in close proximity during foreign body reactions, therefore it was assumed that they might interact with each other. The aim was to identify important genes that are expressed by osteoclasts and FBGCs which can be used to understand peri-implantitis and predict the relationship of these cells during foreign body reactions. Bone marrow macrophages (BMM) were treated with receptor activator of nuclear factor kappa B ligand (RANKL) to produce osteoclasts. Quantitative PCR (qPCR) was used to identify the genes that were expressed by osteoclasts and FBGCs compared to macrophage controls. TRAP staining was used to visualise the cells while gelatine zymography and western blots were used for protein expression. Tartrate-resistant acid phosphatase (TRAP), matrix metallo proteinase 9 (MMP9), nuclear factor of activated T cells 1 (NFATc1), cathepsin K (CTSK) and RANK were significantly lower in FBGCs compared to osteoclasts. Inflammation specific chemokines such as monocyte chemotactic protein (MCP1 also called CCL2), macrophage inflammatory protein 1 alpha (MIP1α), MIP1ß and MIP1γ, and their receptors CCR1, CCR3 and CCR5, were highly expressed by FBGCs. FBGCs were negative for osteoclast specific markers (RANK, NFATc1, CTSK). FBGCs expressed chemokines such as CCL2, 3, 5 and 9 while osteoclasts expressed the receptors for these chemokines i.e. CCR1, 2 and 3. Our findings show that osteoclast specific genes are not expressed by FBGCs and that FBGCs interact with osteoclasts during foreign body reaction through chemokines.

An accurate and computationally efficient model for membrane-type circular-symmetric micro-hotplates.

Ideally, the design of high-performance micro-hotplates would require a large number of simulations because of the existence of many important design parameters as well as the possibly crucial effects of both spread and drift. However, the computational cost of FEM simulations, which are the only available tool for accurately predicting the temperature in micro-hotplates, is very high. As a result, micro-hotplate designers generally have no effective simulation-tools for the optimization. In order to circumvent these issues, here, we propose a model for practical circular-symmetric micro-hot-plates which takes advantage of modified Bessel functions, computationally efficient matrix-approach for considering the relevant boundary conditions, Taylor linearization for modeling the Joule heating and radiation losses, and external-region-segmentation strategy in order to accurately take into account radiation losses in the entire micro-hotplate. The proposed model is almost as accurate as FEM simulations and two to three orders of magnitude more computationally efficient (e.g., 45 s versus more than 8 h). The residual errors, which are mainly associated to the undesired heating in the electrical contacts, are small (e.g., few degrees Celsius for an 800 °C operating temperature) and, for important analyses, almost constant. Therefore, we also introduce a computationally-easy single-FEM-compensation strategy in order to reduce the residual errors to about 1 °C. As illustrative examples of the power of our approach, we report the systematic investigation of a spread in the membrane thermal conductivity and of combined variations of both ambient and bulk temperatures. Our model enables a much faster characterization of micro-hotplates and, thus, a much more effective optimization prior to fabrication.

Foreign body giant cells and osteoclasts are TRAP positive, have podosome-belts and both require OC-STAMP for cell fusion.

Macrophages have the ability to fuse and form multinucleated giant cells such as Osteoclast (OCs) and FBGCs. Osteoclast stimulatory transmembrane protein (OC-STAMP) is an important cell surface protein involved in the formation of OCs. This study sought to determine if OC-STAMP also regulates formation of FBGCs using expression analysis and subsequent inhibition studies. qPCR and Western blot analysis showed that OC-STAMP expression is significantly higher in FBGCs compared to control monocytes (P < 0.05). Four days following cell culture, OCs were positive for TRAP and F-actin ring formation, but FBGCs were not. In contrast, FBGCs were positive for TRAP and showed podosome belts comprised of F-actin on Day 8. FBGCs were subsequently plated onto dentine, but despite presenting some morphologic features of OCs (OC-STAMP expression, TRAP reactivity, and podosome belts) they failed to resorb bone. To evaluate a role for OC-STAMP in FBGCs, we inhibited this cell surface protein with anti-OC-STAMP antibody and observed that cell fusion and podosome belt formation was inhibited in both OCs and FBGCs. Our data support the hypothesis that OC-STAMP is a regulatory molecule for FBGCs; and that they are functionally distinct from OCs, despite similarities in gene expression profile, podosome belt formation, and TRAP expression.

Impact of Coping Veneering Techniques on the Survival of Implant-Supported Zirconia-Based-Crowns Cemented to Hybrid-Abutments: An-In-Vitro Study.

The objective of this study is to investigate the influence of veneering technique (hand-layering vs. milling) on the fracture resistance of bi-layer implant-supported zirconia-based hybrid-abutment crowns. Mandibular molar copings were anatomically designed and milled. Copings were then veneered by hand-layering (HL) (n = 20) and milling using the Cad-On technique (LD) (n = 20). Crowns were cemented to zirconia hybrid-abutments. Ten samples of each group acted as a control while the remaining ten samples were subjected to fatigue in a chewing simulator. Crowns were loaded between 50 and 100 N for 1.2 million cycles under simultaneous temperature fluctuation between 5 and 55 °C. Crowns were then subjected to static load a to fracture test. Data were statistically analysed using the one-way ANOVA. Randomly selected crowns from each group were observed under scanning electron microscopy to view fractured surfaces. Study results indicate that during fatigue, LD crowns had a 100% survival rate; while HL crowns had a 50% failure rate. Fracture resistance of LD crowns was statistically significantly higher than that of HL crowns at the baseline and after fatigue (p ≤ 0.05). However, fatigue did not cause a statistically significant reduction in fracture resistance in both LD and HL groups (p > 0.05). Copings fractured in the LD crowns only and the fracture path was different in both LD and HL groups. According to the results, it was concluded that milled veneer implant-supported hybrid-abutment crowns exhibit significantly higher fracture resistance, and better withstand clinical masticatory loads in the posterior region compared to the hand-layered technique. Also, fatigue application and artificial aging caused no significant strength reduction in both techniques. Clinical significance: Different veneering techniques and materials (hand-layering or milling) act differently to clinical forces and environment and may be prone to early chipping during service. Therefore, practitioners are urged to consider the appropriate veneering protocol for posterior implant-supported hybrid-abutment restorations.

Composite submental flaps in facial reconstructive surgery involving the zygoma and orbit.

BACKGROUND: The submental island flap (SIF) is a reliable option for reconstructing defects in the facial region and offers several advantages when compared to free-flap alternatives. While the reconstructive applications of the SIF have been demonstrated in the lower face, there are limited reports on its utility as a composite flap for reconstructing defects of the upper facial skeleton. To our knowledge, we report the first cases of composite (osteocutaneous) SIFs used for reconstruction of complex facial defects involving the zygoma and lateral orbit respectively. CASE PRESENTATIONS: Three consecutive cases are presented. All were performed following resection of skin cancers with invasion of the upper facial skeleton. The first case was a 68-year-old male with a longstanding history of non-melanoma skin cancers who presented with a 7 cm recurrent basal cell carcinoma (BCC) with bicortical invasion of the left zygoma. The second case was an 88-year-old female with several squamous cell carcinomas (SCC), including a dominant 7.1 cm SCC on the right temple with orbital invasion. A third case was a 75-year-old immunosuppressed male with a 6.5 cm SCC of the right cheek with invasion of the orbit and zygoma following prior resection as well as high dose radiotherapy. The operative management of all cases involved harvesting the SIF on its vascular pedicle alongside the inferior portion of the mandible with rigid fixation to address the bony defects. The first case was robust throughout adjuvant radiotherapy with no flap complications after 2 year follow up. The second patient received adjuvant radiation therapy to an area that was previously radiated. Although the flap remained viable for a year, the patient experienced delayed soft tissue loss over the bony segment and eventual devitalization of the distal flap. The third case achieved a satisfactory result with no complications. CONCLUSIONS: Our case series outlines a unique application of the composite (osteocutaneous) submental island flap (SIF) for reconstruction of complex facial defects involving the upper facial skeleton. The osteocutaneous SIF should be used with caution in patients receiving adjuvant radiotherapy who have a history of previous radiation to the same or overlapping field.

Esthetic Management of a Patient with Severely Fluorosed Enamel and Pigmented Gingiva: A Conservative Approach.

Isolated brown or white defects of less than few tenths of millimeter depth can be successfully treated with microabrasion. However, for deeper enamel defects, a combination of various techniques such as microabrasion/macroabrasion along with bleaching or full or partial veneering are available. Template-assisted direct veneering technique helps for better separation and contouring of individual tooth through which composite resin can be applied directly to tooth structure and artistically sculpted. Frequently, the gingival hyperpigmentation is caused by excessive melanin deposits mainly located in the basal and suprabasal cell layers of the epithelium. Recently, laser ablation has been recognized as one of the most effective, pleasant, and reliable techniques. This article describes a conservative approach for a complete smile makeover of a patient with severe fluorosis and pigmented gingiva with the help of enamel microabrasion and template-assisted direct composite veneering followed by laser depigmentation of gingiva.

A New Multi-Ingredient Recipe for the Treatment of Localized Advanced Periodontal Disease following the Surgical Removal of Impacted Wisdom Teeth.

Periodontal disease is a chronic inflammation of the tooth supporting structures. It leads to bone and attachment loss which is irreversible. Extraction of horizontally impacted lower third molar (L3M) teeth may result in localized periodontal pockets at the distal aspect of the adjacent lower second molars (L2M). We present a case of a 21-year-old male who suffered from a swelling and pain around his lower right second molar following surgical removal of a mesioangular impacted lower right third molar. We showed that oral hygiene measures, surgical access, mixture of autogenous and synthetic bone graft, and guided tissue regeneration (GTR) were enough to control the problem.

In vitro assessment of strength, fatigue durability, and disassembly of Ti6Al4V and CoCrMo necks in modular total hip replacements.

Modularity in total hip replacement offers advantages with regard to biomechanical adjustments and leg lengths. Recently, modular femoral necks were introduced as an added advantage to head modularity permitting further adjustments in femoral version as well as offset and ease of revision. Currently, most necks are made of Ti6Al4V for which cases of in vivo fractures and inseparable neck-stem junctions have been reported. Therefore, we investigated CoCrMo head-Ti6Al4V stem hip replacements with necks made of CoCrMo as an alternative to Ti6Al4V. We compared the two materials with respect to (1) compressive load bearing capacity; (2) fatigue durability; and (3) component distraction. We performed in vitro fatigue-pull-off, microscopy, fatigue durability and compression investigations. The CoCrMo neck showed a load bearing capacity of 18 kN, 38% higher than 13 kN for the Ti6Al4V neck. A fatigue load of 11.2 kN for 1 million cycle failure was achieved with CoCrMo translating into nearly 1000 times longer fatigue life compared to Ti6Al4V necks. The neck-stem distraction force showed large statistical variation and was similar for both neck materials. Overall, the results suggest a superiority of CoCrMo over Ti6Al4V as neck material with regard to mechanical behavior. However, the corrosion behavior was not appropriately assessed and necessitates additional investigations.

Flexible intramedullary nailing in paediatric femoral fractures. A report of 73 cases.

BACKGROUND: Flexible intramedullary nailing has emerged as an accepted procedure for paediatric femoral fractures. Present indications include all patients with femoral shaft fractures and open physis. Despite its excellent reported results, orthopaedic surgeons remain divided in opinion regarding its usefulness and the best material used for nails. We thus undertook a retrospective study of paediatric femoral fractures treated with titanium or stainless steel flexible nails at our institute with a minimum of 5 years follow up. MATERIAL AND METHODS: We included 73 femoral shaft fractures in 69 patients treated with retrograde flexible intramedullary nailing with a minimum follow up of 5 years. Final limb length discrepancy and any angular or rotational deformities were determined. RESULTS: Mean age at final follow up was 15.5 years (10-21 years). Mean follow up was 7.16 years (5.0-8.6 years). Titanium and stainless steel nails were used in 43 and 30 cases respectively. There were 51 midshaft, 17 proximal, and 5 distal fractures.All fractures united at an average of 11 weeks but asymptomatic malalignment and LLD were seen in 19% and 58% fractures respectively. LLD ranged from -3 cm to 1.5 cm. Other complications included superficial infection(2), proximal migration of nail(3), irritation at nail insertion site(5) and penetration of femoral neck with nail tip(1). There were 59 excellent, 10 satisfactory and 4 poor results. CONCLUSION: Flexible intramedullary nailing is reliable and safe for treating paediatric femoral shaft fractures. It is relatively free of serious complications despite asymptomatic malalignment and LLD in significant percentage of fractures.

Retrieval analysis and in vitro assessment of strength, durability, and distraction of a modular total hip replacement.

We investigated a commercial Co-Cr-alloy head--Ti6Al4V alloy neck and Ti6Al4V stem modular total hip replacement. We assessed the distraction forces after in vitro cycling in bovine serum, fatigue durability, fretting corrosion damage, and load bearing capacity of new implants using fatigue-corrosion, pull-off, scanning electron microscopy, fatigue and compression investigations. In addition, we studied corrosion, fretting damage, and distraction forces on retrievals. For both retrievals and in vitro test samples, the neck-stem interface required the higher distraction force as compared with the head-neck interface. One of 12 retrievals showed strong fretting corrosion at the neck-stem interface which resulted in a high disassembly force of about 16 kN. For in vitro test samples, the neck-stem pull-off force initially increased during cycling and showed a maximum value of 5.704 kN at ∼100,000 cycles, which is equivalent to gait cycles performed in approximately 36 days. Overall, assembly force, initial component settling, and interface corrosion primarily determine the force required to distract the modular components. One million cycles fatigue failure of the neck can be expected at a maximum compression load of -6.5 kN. No component failure was observed during quasistatic compression; rather the neck deformed plastically and the ultimate compression load-bearing capacity was -13 kN.