Rationale behind the design and comparative evaluation of an all-in-one self-etch model adhesive

Objective

To investigate and compare bonding and dentin sealing efficacy of a marketed all-in-one and an experimental model adhesive with minimum effective amounts of acidic monomer and water.

Materials and methods

Composition of model adhesive (NAD) in mass%: UDMA (45), 4-META (20), H₂O (7.5), and acetone (27.5). For characterization of a reasonable NAD application procedure shear bond strengths (SBS, n = 8) were determined on human enamel and dentin. Clearfil S³ Bond (TSB; Kuraray) served as reference. SBSs were evaluated after 10 min, 1 and 7 days, and 1 month, marginal adaptation (n = 8) was assessed in cylindrical butt-joint dentin cavities. Diffusive and convective water fluxes through 1 mm thick adhesive-coated dentin disks (n = 6) were qualitatively and quantitatively analyzed.

Results

SBSs proved that application of NAD in one coat with 20 s agitated dwell time was ≥20 MPa, enamel SBSs (24 h) were 25 MPa, p > 0.05. Dentin SBSs for TSB and NAD were not different (p > 0.05) at the four stages (means: 18.9, 23.5, 25.4, and 23.6 MPa). Five and seven of the eight bonded restorations with TSB and NAD were gap-free (p > 0.05). Dentin disks treated with EDTA from both sides or one side only were highly permeable for liquid, whereas adhesive-coated dentin disks showed no permeability at 0 and 2.5 kPa water pressure.

Conclusions

Within the limitations of this study the model adhesive tested represents a promising basic composition for all-in-one adhesives, eliminating common problems encountered with single step adhesives such as phase separation and permeability.     

Effects of age on the stress-strain and stress-relaxation properties of the rat molar periodontal ligament

OBJECTIVE: We examined the stress-strain and stress-relaxation properties of the periodontal ligament (PDL) in the rat molar at 2, 6, 12, and 24 months of age to elucidate age-related changes in the tooth support function of the PDL. DESIGN: From the dissected left and right mandibles in each rat, a pair of transverse sections (ca. 0.45 mm in thickness) of the first molar was cut at the middle part of the mesial root. We then obtained a load-deformation curve for the PDL, using one of the paired sections. The other section was loaded to as much as 50% of the maximum load as determined from the contralateral section, and keeping the deformation constant for 10 min, a load-relaxation curve was obtained and analysed. RESULTS: The maximum shear stress and tangent modulus decreased between 2 and 24 months of age. As the maximum shear strain increased with age (P < 0.001), the failure strain energy density did not change between 2 and 24 months of age. The stress-relaxation during the 10 min period decreased from 2 to 24 months of age (P < 0.01). The relaxation process of the PDL in each age was well described by a sum of three exponential decay functions. The age-related decrease in the relaxation was found to be mainly due to the increase in the relaxation time for the long-term relaxation component. CONCLUSION: These results indicate that the maximum shear stress and stiffness of the rat molar PDL decrease between 2 and 24 months of age; but its toughness remains unchanged due to an increase in the extensibility. Our findings further indicate that the fluid flow and movements of macromolecules within the stretched PDL fibres during the stress-relaxation decrease with advancing age.     

Microvascular response in the periosteum following mucoperiosteal flap surgery in dogs: angiogenesis and bone resorption and formation

BACKGROUND: When surgical stress reaches the periosteum, bone resorption and formation that occur as a periosteal response are closely related to angiogenesis and hemodynamics. Thus, we investigated bone remodeling in the healing process after mucoperiosteal flap surgery, focusing our attention on the microcirculation. METHODS: Mucoperiosteal flap surgery was performed on 12 adult beagle dogs. The periosteal vascular plexus was observed on days 7, 14, 21, and 28 after surgery, using three different techniques: in histological specimens into which India ink was injected into blood vessels, under a light microscope; in ultrathin sections, using a transmission electron microscope; and in acryl plastic-injected vascular corrosion cast specimens, under a scanning electron microscope. RESULTS: On day 7 after surgery, the interstitum of the elevated mucoperiosteal vascular plexus was filled with sinusoidal new blood vessels. Bone resorption by osteoclasts was observed around these new blood vessels and many highly permeable fenestrations were present in the vascular endothelium. On day 14 after surgery, sinusoidal new blood vessels were more markedly developed and some regions exhibited glomeruluslike morphology consistent with bone resorption cavities. Activated osteoblasts were present around these new blood vessels and highly permeable vesicles, which were considered to be possible vesiclo-vacuolar organelles (VVOs) and caveolae, were noted in the vascular endothelium. On days 21 and 28 after surgery, the mucoperiosteal vascular plexus was dissected through regression of endothelial cells and fibroblasts and reconstructed into a rough mesh structure, and simultaneously the bone surface became smooth. CONCLUSION: The morphology of the mucoperiosteal vascular plexus changed with bone metabolism and these changes contributed to transport of substances involved in periodontal repair.     

Organization and cellular arrangement of two neurogenic regions in the adult ferret (Mustela putorius furo) brain

In the adult mammalian brain, two neurogenic regions have been characterized, the subventricular zone (SVZ) of the lateral ventricle (LV) and the subgranular zone (SGZ) of the dentate gyrus (DG). Despite remarkable knowledge of rodents, the detailed arrangement of neurogenic regions in most mammals is poorly understood. In this study, we used immunohistochemistry and cell type‐specific antibodies to investigate the organization of two germinal regions in the adult ferret, which belongs to the order Carnivora and is widely used as a model animal with a gyrencephalic brain. From the SVZ to the olfactory bulb, doublecortin‐positive cells tended to organize in chain‐like clusters, which are surrounded by a meshwork of astrocytes. This structure is homologous to the rostral migratory stream (RMS) described in other species. Different from rodents, the horizontal limb of the RMS emerges directly from the LV, and the anterior region of the LV extends rostrally and reached the olfactory bulb. In the DG, glial fibrillary acidic protein‐positive cells with long radial processes as well as doublecortin‐positive cells are oriented in the SGZ. In both regions, doublecortin‐positive cells showed characteristic morphology and were positive for polysialylated‐neural cell adhesion molecule, beta‐III tubulin, and lamin B1 (intense staining). Proliferating cells were detected in both regions using antibodies against proliferating cell nuclear antigen and phospho‐histone H3. These observations demonstrate that the two neurogenic regions in ferrets have a similar cellular composition as those of other mammalian species despite anatomical differences in the brain. J. Comp. Neurol. 522:1818–1838, 2014. © 2013 Wiley Periodicals, Inc.     

Multiple calcifying lesions in the maxilla and mandible of a 4-year-old girl: report of a rare case and literature review

Calcifying lesions in the jaws are usually solitary and can be diagnosed by intraoral, panoramic, and conventional extraoral radiographs. It is extremely rare for these calcifying lesions to be multiple, unless they are associated with certain systematic diseases. Herein, we report a rare case of multiple odontomas in a 4-year-old girl. The lesions were scattered throughout both jaws on the panoramic image. The reconstructed CT image showed lesions in the left maxilla that occupied the sinus and affected the floor of the left orbit. The lesions in the mandible were widespread and extended to the tooth-bearing area. Enucleations of the maxillary parts were performed, and the pathological diagnosis was a mixture of complex and compound odontomas. The 3-year postoperative follow-up by panoramic imaging was uneventful. Preoperative CT was useful for the differential diagnosis by depicting the internal calcifying lesions and revealing the extent and complex relationships among the lesions.     

Pyloric narrowing with increased fibrous tissue of the mucosa in an infant

An infant with pyloric narrowing following bilious vomiting is described. Barium meal studies demonstrated fixed narrowing of the pyloric canal similar to infantile hypertrophic pyloric stenosis. However, sonographic examination failed to prove significant muscular hypertrophy of the pylorus. Histology of the pre-pyloric mucosal biopsy specimens showed nonspecific inflammation with increased fibrous tissue of the mucosa. Repeated histological examination revealed regression of mucosal inflammation; the patient became symptom free and normal growth was confirmed at 2 years of age. It is possible that antral/pyloric mucosal inflammation, the pathogenesis of which remains unclear, was the cause of pyloric narrowing and then led to nonbilious vomiting.     

Protein-bound polysaccharide K induced apoptosis of the human Burkitt lymphoma cell line, Namalwa.

Protein-bound polysaccharide K (PSK), which is derived from mushrooms belonging to the Basidiomycetes genus, has been clinically used as a biological response modifier (BRM) for the treatment of epithelial cancer patients in Japan and other Asian countries. There are a large number of studies on the biological activities of PSK as regards the activation of immunocompetent cells and the potential cytotoxic effects on epithelial cancer cells. However, only a few studies have been conducted to see the direct cytotoxic effects of PSK on hematological malignant cells. In this study, we investigated whether or not PSK was able to induce cellular apoptosis in hematological malignant cells. PSK was found to inhibit cell growth, and induced subsequent cellular apoptosis in the Burkkit lymphoma cell line (Namalwa), out of 33 hematological malignant cell lines tested. This PSK-induced apoptosis was neutralized by the addition of galactose to the culture medium, whereas apoptosis was augmented by treatment with beta-galactosidase, indicating the inhibitory involvement of galactose in the mechanism of action. These results provide initial evidence of the direct cytotoxic activity of PSK in a hematological malignant cell line, thus encouraging further molecular-level study of PSK-mediated apoptosis in malignant hematological cells.     

Hand lesion after arthroscopic rotator cuff repair: Association with complex regional pain syndrome

Background

It is known that complex regional pain syndrome (CRPS) occurs after arthroscopic rotator cuff repair (ARCR); however, few studies have investigated this complication. Therefore, the purpose of the present study was to evaluate CRPS after ARCR.

Posttransplant oxygen inhalation improves the outcome of subcutaneous islet transplantation: A promising clinical alternative to the conventional intrahepatic site

Subcutaneous tissue is a promising site for islet transplantation, due to its large area and accessibility, which allows minimally invasive procedures for transplantation, graft monitoring, and removal of malignancies as needed. However, relative to the conventional intrahepatic transplantation site, the subcutaneous site requires a large number of islets to achieve engraftment success and diabetes reversal, due to hypoxia and low vascularity. We report that the efficiency of subcutaneous islet transplantation in a Lewis rat model is significantly improved by treating recipients with inhaled 50% oxygen, in conjunction with prevascularization of the graft bed by agarose–basic fibroblast growth factor. Administration of 50% oxygen increased oxygen tension in the subcutaneous site to 140 mm Hg, compared to 45 mm Hg under ambient air. In vitro, islets cultured under 140 mm Hg oxygen showed reduced central necrosis and increased insulin release, compared to those maintained in 45 mm Hg oxygen. Six hundred syngeneic islets subcutaneously transplanted into the prevascularized graft bed reversed diabetes when combined with postoperative 50% oxygen inhalation for 3 days, a number comparable to that required for intrahepatic transplantation; in the absence of oxygen treatment, diabetes was not reversed. Thus, we show oxygen inhalation to be a simple and promising approach to successfully establishing subcutaneous islet transplantation.