Dissecting human anatomy learning process through anatomical education with augmented reality: AEducAR 2.0, an updated interdisciplinary study.

Anatomical education is pivotal for medical students, and innovative technologies like augmented reality (AR) are transforming the field. This study aimed to enhance the interactive features of the AEducAR prototype, an AR tool developed by the University of Bologna, and explore its impact on human anatomy learning process in 130 second-year medical students at the International School of Medicine and Surgery of the University of Bologna. An interdisciplinary team of anatomists, maxillofacial surgeons, biomedical engineers, and educational scientists collaborated to ensure a comprehensive understanding of the study's objectives. Students used the updated version of AEducAR, named AEducAR 2.0, to study three anatomical topics, specifically the orbit zone, facial bones, and mimic muscles. AEducAR 2.0 offered two learning activities: one explorative and one interactive. Following each activity, students took a test to assess learning outcomes. Students also completed an anonymous questionnaire to provide background information and offer their perceptions of the activity. Additionally, 10 students participated in interviews for further insights. The results demonstrated that AEducAR 2.0 effectively facilitated learning and students' engagement. Students totalized high scores in both quizzes and declared to have appreciated the interactive features that were implemented. Moreover, interviews shed light on the interesting topic of blended learning. In particular, the present study suggests that incorporating AR into medical education alongside traditional methods might prove advantageous for students' academic and future professional endeavors. In this light, this study contributes to the growing research emphasizing the potential role of AR in shaping the future of medical education.

Anatomical Study of the Application of a Galeo-Pericranial Flap in Oral Cavity Defects Reconstruction.

Oral cavity defects occur after resection of lesions limited to the mucosa, alveolar gum, or minimally affecting the bone. Aiming at esthetical and functional improvements of intraoral reconstruction, the possibility of harvesting a new galeo-pericranial free flap was explored. The objective of this study was to assess the technical feasibility of flap harvesting through anatomical dissections and surgical procedure simulations. Ten head and neck specimens were dissected to simulate the surgical technique and evaluate the vascular calibers of temporal and cervical vessels. The procedure was therefore reproduced on a revascularized and ventilated donor cadaver. Anatomical dissections demonstrated that the mean cervical vascular calibers are compatible with superficial temporal ones, proving to be adequate for anastomosis. Perforating branches of the superficial temporal vascularization nourishing the pericranium were identified in all specimens. In conclusion, blood flow presence was recorded after anastomosing superficial temporal and facial vessels in the revascularized donor cadaver, demonstrating both this procedure's technical feasibility and the potential revascularization of the flap and therefore encouraging its potential in vivo application.

AEducaAR, Anatomical Education in Augmented Reality: A Pilot Experience of an Innovative Educational Tool Combining AR Technology and 3D Printing.

Gross anatomy knowledge is an essential element for medical students in their education, and nowadays, cadaver-based instruction represents the main instructional tool able to provide three-dimensional (3D) and topographical comprehensions. The aim of the study was to develop and test a prototype of an innovative tool for medical education in human anatomy based on the combination of augmented reality (AR) technology and a tangible 3D printed model that can be explored and manipulated by trainees, thus favoring a three-dimensional and topographical learning approach. After development of the tool, called AEducaAR (Anatomical Education with Augmented Reality), it was tested and evaluated by 62 second-year degree medical students attending the human anatomy course at the International School of Medicine and Surgery of the University of Bologna. Students were divided into two groups: AEducaAR-based learning ("AEducaAR group") was compared to standard learning using human anatomy atlas ("Control group"). Both groups performed an objective test and an anonymous questionnaire. In the objective test, the results showed no significant difference between the two learning methods; instead, in the questionnaire, students showed enthusiasm and interest for the new tool and highlighted its training potentiality in open-ended comments. Therefore, the presented AEducaAR tool, once implemented, may contribute to enhancing students' motivation for learning, increasing long-term memory retention and 3D comprehension of anatomical structures. Moreover, this new tool might help medical students to approach to innovative medical devices and technologies useful in their future careers.

An Ancient Science to Improve Today's Clinical Practice: Oral Surgery Meets Human Anatomy.

Human body dissection was a ubiquitous practice in the past, to better understand anatomy and to develop medicine. Today, its role could still be important to answer everyday clinical queries and help surgeons. The example of the possible lack of anesthesia during symphysis surgeries can emphasize the usefulness of dissection. The mandibular symphysis usually receives innervation from inferior alveolar nerve terminations, but, in some rare cases, a particular anastomosis involves the lingual nerve and the nerve to the mylohyoid. The anatomical knowledge resulting from body dissections could help oral surgeons to understand the reason why the patient could feel pain during the surgery, and ensure performance of the right lingual nerve block to obtain complete anesthesia. This clinical situation shows the educational role of an ancient, yet still valid, practice, human dissection, and the importance of anatomical studies to improve surgical skills, to provide better treatment for the patient.

Assessment of the structural and functional characteristics of human mesenchymal stem cells associated with a prolonged exposure of morphine.

The discovery of the expression of opioid receptors in the skin and their role in orchestrating the process of tissue repair gave rise to questions regarding the potential effects of clinical morphine treatment in wound healing. Although short term treatment was reported to improve tissue regeneration, in vivo chronic administration was associated to an impairment of the physiological healing process and systemic fibrosis. Human mesenchymal stem cells (hMSCs) play a fundamental role in tissue regeneration. In this regard, acute morphine exposition was recently reported to impact negatively on the functional characteristics of hMSCs, but little is currently known about its long-term effects. To determine how a prolonged treatment could impair their functional characteristics, we exposed hMSCs to increasing morphine concentrations respectively for nine and eighteen days, evaluating in particular the fibrogenic potential exerted by the long-term exposition. Our results showed a time dependent cell viability decline, and conditions compatible with a cellular senescent state. Ultrastructural and protein expression analysis were indicative of increased autophagy, suggesting a relation to a detoxification activity. In addition, the enhanced transcription observed for the genes involved in the synthesis and regulation of type I collagen suggested the possibility that a prolonged morphine treatment might exert its fibrotic potential risk, even involving the hMSCs.

Cellular senescence in vascular wall mesenchymal stromal cells, a possible contribution to the development of aortic aneurysm.

Cellular senescence is a hallmark of ageing and it plays a key role in the development of age-related diseases. Abdominal aortic aneurysm (AAA) is an age related degenerative vascular disorder, characterized by a progressive dilatation of the vascular wall and high risk of rupture over time. Nowadays, no pharmacological therapies are available and the understanding of the molecular mechanisms that lead to AAA onset and development are poorly defined. In this study we investigated the cellular features of senescence in vascular mesenchymal stromal cells, isolated from pathological (AAA - MSCs) and healthy (h - MSCs) segments of human abdominal aorta and their implication in impairing the vascular repair ability of MSCs. Cell proliferation, ROS production, cell surface area, the expression of cyclin dependent kinase inhibitors p21CIP1 and p16INK4a, the activation of the DNA damage response and a dysregulated autophagy showed a senescent state in AAA - MSCs compared to h-MSCs. Moreover, a reduced ability to differentiate toward endothelial cells was observed in AAA - MSCs. All these data suggest that the accumulation of senescent vascular MSCs over time impairs their remodeling ability during ageing. This condition could support the onset and development of AAA.

Augmented Reality-Assisted Periosteum Pedicled Flap Harvesting for Head and Neck Reconstruction: An Anatomical and Clinical Viability Study of a Galeo-Pericranial Flap.

Head and neck reconstructive surgeons have recently explored new perspectives in bone restoration using periosteum carrier flaps. Following this idea, we explored the possibility of harvesting a galeo-pericranial flap. The present work studies the vascular supply of the pericranial temporo-parietal region in order to assess the possibility of harvesting a galeo-pericranial flap based on the superficial temporalis vascularization. Anatomical dissections were performed at the Anatomical Institute of the University of Bologna on eight donor cadavers. Then we performed the harvesting of the flap in vivo on eight patients. We introduced augmented reality (AR) to facilitate anatomical visualisation during free flap harvesting. Augmented reality merges virtual and actual objects, allowing direct observation of patient anatomy and the surgical field. No post-operative major or minor complications occurred. We encountered no post-operative functional issues on the donor or recipient sites, and good clinical healing was observed in all patients. In conclusion, we believe that the galea-pericranium flap could represent a new donor site for the harvesting of a periosteum carrier flap.

Calreticulin: Challenges Posed by the Intrinsically Disordered Nature of Calreticulin to the Study of Its Function.

Calreticulin is a Ca2+-binding chaperone protein, which resides mainly in the endoplasmic reticulum but also found in other cellular compartments including the plasma membrane. In addition to Ca2+, calreticulin binds and regulates almost all proteins and most of the mRNAs deciding their intracellular fate. The potential functions of calreticulin are so numerous that identification of all of them is becoming a nightmare. Still the recent discovery that patients affected by the Philadelphia-negative myeloproliferative disorders essential thrombocytemia or primary myelofibrosis not harboring JAK2 mutations carry instead calreticulin mutations disrupting its C-terminal domain has highlighted the clinical need to gain a deeper understanding of the biological activity of this protein. However, by contrast with other proteins, such as enzymes or transcription factors, the biological functions of which are strictly defined by a stable spatial structure imprinted by their amino acid sequence, calreticulin contains intrinsically disordered regions, the structure of which represents a highly dynamic conformational ensemble characterized by constant changes between several metastable conformations in response to a variety of environmental cues. This article will illustrate the Theory of calreticulin as an intrinsically disordered protein and discuss the Hypothesis that the dynamic conformational changes to which calreticulin may be subjected by environmental cues, by promoting or restricting the exposure of its active sites, may affect its function under normal and pathological conditions.

IPMK and ß-catenin mediate PLC-ß1-dependent signaling in myogenic differentiation.

In previous studies, we have reported that phospholipase C (PLC)-ß1 plays a crucial role in myogenic differentiation and we determined the importance of its catalytic activity for the initiation of this process. Here we define the effectors that take part to its signaling pathway. We show that the Inositol Polyphosphate Multikinase (IPMK) is able to promote myogenic differentiation since its overexpression determines the up-regulation of several myogenic markers. Moreover, we demonstrate that IPMK activates the same cyclin D3 promoter region targeted by PLC-ß1 and that IPMK-induced promoter activation relies upon c-jun binding to the promoter, as we have shown previously for PLC-ß1. Furthermore, our data shows that IPMK overexpression causes an increase in ß-catenin translocation and accumulation to the nuclei of differentiating myoblasts resulting in higher MyoD activation. Finally, we describe that PLC-ß1 overexpression determines too an increase in ß-catenin translocation and that PLC-ß1, IPMK and ß-catenin are mediators of the same signaling pathway since their overexpression results in cyclin D3 and myosin heavy chain (MYH) induction.

Endoscopic endonasal anatomy of the ophthalmic artery in the optic canal.

BACKGROUND: The endoscopic endonasal opening of the optic canal has been recently proposed for tumors with medial invasion of this canal, such as tuberculum sellae meningiomas. Injury of the ophthalmic artery represents a dramatic risk during this maneuver. Therefore, the aim of this study was to analyze the endoscopic endonasal anatomy of the precanalicular and canalicular portion of this vessel, discussing its clinical implication. METHODS: The course of the ophthalmic artery was analyzed through five endoscopic endonasal dissections, and 40 nonpathological consecutive MRAs were reviewed. RESULTS: The ophthalmic artery arises from the intradural portion of the supraclinoid internal carotid artery, in 93 % of cases about 1.9 mm (range: 1-3) posterior to the falciform ligament. At the entrance into the optic canal, the ophthalmic artery is located infero-medially to the optic nerve in 13 % of cases. In 50 % of these cases the artery moves infero-laterally along its course, remaining in a medial position in the others. In cases with an non medial entrance of the ophthalmic artery, it runs infero-lateral to the optic nerve for its entire canalicular portion, with just one exception. CONCLUSION: The endoscopic endonasal approach gives a direct, extensive and panoramic view of the course of the precanalicular and canalicular portion of the ophthalmic artery. Dedicated high-field neuroimaging studies are of paramount importance in preoperative planning to evaluate the anatomy of the ophthalmic artery, reducing the risk of jeopardizing the vessel, particularly for those uncommon cases with an infero-medial course of the artery.

ADAM10 localization in temporomandibular joint disk with internal derangement: an ex vivo immunohistochemical study.

The purpose of this study was to determine the presence of ADAM10 in temporomandibular joint disk with internal derangement. Twenty-five paraffin blocks of displaced temporomandibular joint (TMJ) disk specimens from earlier investigations were retrieved from the archives of the University of Catania. Of these 16 had been removed from females and 9 from males; 11 with anterior disk displacement with reduction (ADDwR) and 14 with anterior disk displacement without reduction (ADDwoR). The sections were dehydrated, embedded in paraffin and cut. Then they were incubated in 0.3% H2O2/methanol and half of sections from each sample were incubated in diluted rabbit polyclonal anti-ADAM10 antibody. Then biotinylated anti-mouse/anti-rabbit IgG was applied to the sections, followed by avidin-biotin-perioxidase complex. The results were analyzed and the results were that ADAM10 was overexpressed in the posterior band of sections from patients with ADDwR compared to the other bands of both ADDwR and ADDwoR sections. Overexpression correlated with severe histopathological degeneration. We believe these results have the potential to provide insights into the pathogenesis of TMJ disk degeneration and to help design new therapeutic approaches targeting the proteolytic events that lead to tissue degeneration. Early therapeutic block of ADAM10 activity could succeed in limiting aggrecan-rich matrix breakdown without affecting normal physiology.

Detection of Virulence Genes and Growth Potential in Listeria monocytogenes Strains Isolated from Ricotta Salata Cheese.

Ricotta Salata is a traditional ripened and salted whey cheese made in Sardinia (Italy) from sheep's milk. This product is catalogued as ready-to-eat food (RTE) since it is not submitted to any further treatment before consumption. Thus, foodborne pathogens, such as Listeria monocytogenes, can represent a health risk for consumers. In September 2012, the FDA ordered the recall of several batches of Ricotta Salata imported from Italy linked to 22 cases of Listeriosis in the United States. This study was aimed at evaluating the presence and virulence properties of L. monocytogenes in 87 samples of Ricotta Salata produced in Sardinia. The ability of this product to support its growth under foreseen packing and storing conditions was also evaluated in 252 samples. Of the 87 samples 17.2% were positive for the presence of L. monocytogenes with an average concentration of 2.2 log10 cfu/g. All virulence-associated genes (prfA, rrn, hlyA, actA, inlA, inlB, iap, plcA, and plcB) were detected in only one isolated strain. The Ricotta Salata samples were artificially inoculated and growth potential (δ) was assessed over a period of 3 mo. The value of the growth potential was always >0.5 log10 cfu/g under foreseen packing and storing conditions. This study indicates that Ricotta Salata supports the L. monocytogenes growth to levels that may present a serious risk to public health, even while stored at refrigeration temperatures.

HEMA but not TEGDMA induces autophagy in human gingival fibroblasts.

Polymerized resin-based materials are successfully used in restorative dentistry. Despite their growing popularity, one drawback is the release of monomers from the polymerized matrix due to an incomplete polymerization or degradation processes. Released monomers are responsible for several adverse effects in the surrounding biological tissues, inducing high levels of oxidative stress. Reactive oxygen species are important signaling molecules that regulate many signal-trasduction pathways and play critical roles in cell survival, death, and immune defenses. Reactive oxygen species were recently shown to activate autophagy as a mechanism of cell survival and cell death. Although the toxicity induced by dental resin monomers is widely studied, the cellular mechanisms underlying these phenomena are still unknown. The aim of the study was to investigate the behavior of human gingival cells exposed to 2-hydroxy-ethyl methacrylate (HEMA) and triethylene glycol dimethacrylate (TEGDMA) to better elucidate the mechanisms of cell survival and cell death induced by resin monomers. Primary culture of human gingival cells were exposed to 3 mmol/L of HEMA or 3 mmol/L of TEGDMA for 24, 48, and 72 h. Morphological investigations were performed by transmission electron microscopy to analyze the ultrastructure of cells exposed to the monomers. The expression of protein markers for apoptosis (caspase - 3 and PARP) and autophagy (beclin - 1 and LC3B I/II) were analyzed by western blot to investigate the influence of dental resin monomers on mechanisms underlying cell death. Results showed that HEMA treatment clearly induced autophagy followed by apoptosis while the lack of any sign of autophagy activation is observed in HGFs exposed to TEGDMA. These data indicate that cells respond to monomer-induced stress by the differential induction of adaptive mechanisms to maintain cellular homeostasis.

A novel interaction between megakaryocytes and activated fibrocytes increases TGF-ß bioavailability in the Gata1(low) mouse model of myelofibrosis.

Despite numerous circumstantial evidences, the pathogenic role of TGF-ß in primary myelofibrosis (PMF), the most severe of the Philadelphia-negative myeloproliferative neoplasms, is still unclear because of the modest (2-fold) increases in its plasma levels observed in PMF patients and in the Gata1(low) mouse model. Whether myelofibrosis is associated with increased bioavailability of TGF-ß bound to fibrotic fibres is unknown. Transmission electron-microscopy (TEM) observations identified that spleen from PMF patients and Gata1(low) mice contained megakaryocytes with abnormally high levels of TGF-ß and collagen fibres embedded in their cytoplasm. Additional immuno-TEM observations of spleen from Gata1(low) mice revealed the presence of numerous activated fibrocytes establishing with their protrusions a novel cellular interaction, defined as peripolesis, with megakaryocytes. These protrusions infiltrated the megakaryocyte cytoplasm releasing collagen that was eventually detected in its mature polymerized form. Megakaryocytes, engulfed with mature collagen fibres, acquired the morphology of para-apoptotic cells and, in the most advanced cases, were recognized as polylobated heterochromatic nuclei surrounded by collagen fibres strictly associated with TGF-ß. These areas contained concentrations of TGF-ß-gold particles ~1000-fold greater than normal and numerous myofibroblasts, an indication that TGF-ß was bioactive. Loss-of-function studies indicated that peripolesis between megakaryocytes and fibrocytes required both TGF-ß, possibly for inducing fibrocyte activation, and P-selectin, possibly for mediating interaction between the two cell types. Loss-of-function of TGF-ß and P-selectin also prevented fibrosis. These observations identify that myelofibrosis is associated with pathological increases of TGF-ß bioavailability and suggest a novel megakaryocyte-mediated mechanism that may increase TGF-ß bioavailability in chronic inflammation.

Electrical properties of resin monomers used in restorative dentistry.

OBJECTIVES: The application of an electric field has been shown to positively influence the impregnation of the resin monomers currently used in dentin bonding systems during hybrid layer formation. This study presents an experimental characterization of the electrical properties of these monomers with the aim of both correlating them to their chemical structures and seeking an insight into the mechanisms of the monomer migration under an applied electric field. METHODS: Some common monomers examined were TEGDMA (triethyleneglycoldimethacrylate), HEMA (2-hydroxyethyl methacrylate), UDMA (urethane dimethacrylate), 2-MP (bis[2-(methacryloyloxy)ethyl] phosphate, TCDM di(hydroxyethyl methacrylate) ester of 5-(2,5-dioxotetrahydrofurfuryl)-3-methyl-3-cyclohexenyl-1,2-dicarboxylic anhydride) and Bis-GMA [2,2-bis(4-2-hydroxy-3-methacryloyloxypropoxyphenyl)propane]. A customized cell produced for the measurement of the electrical properties of monomers was manufactured and electrical conductivity and permittivity of resin monomers were measured. RESULTS: The permittivity of the tested monomers is largely affected by electrical frequency. The large values of permittivity and dielectric losses observed as frequency decreased, indicate a dominant effect of ionic polarization, particularly evident in materials showing the highest conductivity. Permittivity and conductivity of the tested monomers showed a similar behavior, i.e. materials with the lowest permittivity also show small values of conductivity and vice versa. SIGNIFICANCE: The results of the present study revealed a good correlation between electrical properties and Hoy solubility parameters and, in particular, the higher the polar contribution (polar forces plus hydrogen bonding) the higher the permittivity and conductivity. The most relevant outcome of this study is that the electrophoretic mechanism prevails on the electroendoosmotic effect in determining the monomer migration under the application of electric fields.

Effects of pH, ionic strength, and applied voltage on migration of dental monomers in an organic matrix.

OBJECTIVES: The application of an electric field has been shown to positively influence the bonding of dentin bonding systems (DBS) by improving adhesive impregnation into dentin. However, the mechanism responsible for this phenomenon has not been completely elucidated. The aim of this study was to clarify the effects of pH, matrix ionic strength, and applied voltage on the migration of commonly used DBS monomers in a model matrix (agarose gel). METHODS: Some common monomers examined were bis-GMA (2,2-bis[4-(2-hydroxy-3-methacryloyloxy propoxy) phenyl] propane); HEMA (2-hydroxyethyl methacrylate); 2-MP (bis[2-(methacryloyloxy) ethyl] phosphate); TCDM [di(hydroxyethyl methacrylate) ester of 5-(2,5,-dioxo tetrahydrofurfuryl)-3-methyl-3-cyclohexenyl-1,2-dicarboxylic acid]; and TEGDMA (triethylene glycol dimethacrylate). Agarose gels poured into a horizontal 10-well electrophoretic cell were used to mimic the collagen fibrils of the dentin organic matrix. The role of pH, matrix ionic strength, and voltage on monomer migration was assayed by modifying the experimental conditions. RESULTS: Results of experiments performed at pH 3.1, 6.3, 8.5, and 12.3; at low, medium, and high ionic strength; and at 50 and 100 V clearly showed that DBA monomer migration toward both the anode and the cathode can be affected by each of these parameters. SIGNIFICANCE: Migration of acrylic monomers toward the anode or cathode can be achieved as desired by selective choice of pH, ionic strength, and applied voltage. Additional studies are needed to evaluate the synergistic effects of DBS monomer blends on migration in an electric field.

Immunohistochemical and biochemical assay of MMP-3 in human dentine.

OBJECTIVE: The function of endogenous MMP-3 and its distribution within the human dentine is unclear. Thus, the aim of the present study was to assay the presence and distribution of MMP-3 within human sound dentine by means of biochemical and immunohistochemical assays. METHODS: Powdered dentine from extracted human teeth was prepared and (1) partially demineralised with 1% H(3)PO(4) for 10min or (2) untreated (control). The presence of MMP-3 was measured using a colorimetric assay system (QuantiSir™, Epigentek, USA). Additional cryo-fractured dentine fragments were processed for immunohistochemical identification of MMP-3 under FEI-SEM. Casein-zymography was used to investigate MMP-3 activity. RESULTS: MMP-3 detected level was 2.732ng/µL in partially demineralised dentine powder, whilst it increased to 3.280ng/µL in mineralised dentine. The FEI-SEM analysis revealed positive immunolabelling patterns for MMP-3, predominantly localized on the intertubular collagen fibrillar network showing MMP-3 directly or indirectly bound to the collagen fibrils. Casein-zymograms showed positive proteolytic activity for MMP-3 in demineralised dentine powder. CONCLUSION: The results of the study clearly revealed the presence and distribution of MMP3 in human sound dentine. Whilst the presence was verified, its role is still unclear. Future studies are needed to investigate the possible involvement of MMP-3 in physiological and pathological condition of the dentine-pulp complex.

Chlorhexidine stabilizes the adhesive interface: a 2-year in vitro study.

OBJECTIVES: This study evaluated the role of endogenous dentin MMPs in auto-degradation of collagen fibrils within adhesive-bonded interfaces. The null hypotheses tested were that adhesive blends or chlorhexidine digluconate (CHX) application does not modify dentin MMPs activity and that CHX used as therapeutic primer does not improve the stability of adhesive interfaces over time. METHODS: Zymograms of protein extracts from human dentin powder incubated with Adper Scotchbond 1XT (SB1XT) on untreated or 0.2-2% CHX-treated dentin were obtained to assay dentin MMPs activity. Microtensile bond strength and interfacial nanoleakage expression of SB1XT bonded interfaces (with or without CHX pre-treatment for 30s on the etched surface) were analyzed immediately and after 2 years of storage in artificial saliva at 37 degrees C. RESULTS: Zymograms showed that application of SB1XT to human dentin powder increases MMP-2 activity, while CHX pre-treatment inhibited all dentin gelatinolytic activity, irrespective from the tested concentration. CHX significantly lowered the loss of bond strength and nanoleakage seen in acid-etched resin-bonded dentin artificially aged for 2 years. SIGNIFICANCE: The study demonstrates the active role of SB1XT in dentin MMP-2 activation and the efficacy of CHX inhibition of MMPs even if used at low concentration (0.2%).

ElectroBond improves immediate dentin microtensile bond strength of two etch-and-rinse adhesives.

PURPOSE: The aim of this study was to investigate whether an electrical device for dental adhesive application (ElectroBond) influences bonding of two-step etch-and-rinse adhesives. MATERIALS AND METHODS: Human teeth were selected and cut perpendicularly to their long axis to expose middle/ deep dentin. Specimens were then longitudinally sectioned into halves (experimental and control halves) to create two similar bonding substrates. Experimental halves were bonded using an ElectroBond-assisted application, while control halves were bonded with disposable sponges. The adhesives tested were Adper Scotchbond 1XT and XP-BOND. Bonded specimens were submitted to the microtensile bond strength test. Additional adhesive interfaces were prepared and processed for nanoleakage investigation involving TEM examination. RESULTS: The microtensile bond test revealed higher values (p < 0.05) for both adhesives if ElectroBond was used during layering (55.5 +/- 7.9 MPa for Adper Scotchbond 1XT and 54.7 +/- 7.1 MPa for XP-BOND) compared to the conventional mechanical adhesive application technique (41.1 +/- 6.1 MPa for Adper Scotchbond 1XT and 38.0 +/- 7.8 MPa for XP-BOND). No difference between the two adhesives was found under the same application conditions. With electricity-assisted application, TEM micrographs revealed a significant decrease in nanoleakage expression compared to the controls. CONCLUSION: The use of an electric current produced by ElectroBond during the application of two-step etch-and-rinse adhesives may enhance resin impregnation, thus improving dentin hybridization. Further studies should be done to confirm that this device can similarly improve adhesive application in vivo.

Influence of a commercial tattoo ink on protein production in human fibroblasts.

Tattooing is an ancient art and is still widely practiced all over the world. Since the biocompatibility of tattoo dyes has not been well researched, we studied the toxicity of a commercial tattoo ink, commonly used in tattoo lab and esthetic centers, on human fibroblasts. To test cell viability, MTT assays were carried out and scanning electron microscopy to visualize changes in the cell surface after the dye exposure was performed. A possible influence of the pigment on the expression of procollagen alpha1 type I protein was visualized by western blotting analysis. The results showed a reduction in cell viability, and electron microscopy demonstrated an unmodified cell surface completely covered by pigment particles. Western blotting analysis demonstrated a clear interference of the pigment on the expression of procollagen alpha1 type I protein. These data demonstrated that the commercial tattoo dye has a time-dependent effect on protein expression. A possible connection of the influence of the tattoo ink with clinical effects is discussed.