Using Pegylated Graphene Oxide to Achieve High Performance Solid Polymer Electrolyte Based on Poly(ethylene oxide)/Polyvinyl Alcohol Blend (PEO/PVA).

Solid polymer electrolytes (SPEs) have emerged as a promising avenue for developing flexible lithium-ion batteries. However, the low ionic conductivity of polymers remains a primary challenge that has been the subject of intensive research efforts in recent years. In this work, polyethylene oxide (PEO), polyvinyl alcohol, lithium perchlorate (LiClO4), and graphene functionalized with polyethylene glycol (FGO) have been used to prepare SPE/FGO electrolytes by casting solution technique. X-ray diffraction (XRD) and differential scanning calorimetry (DSC) confirmed the reduction of SPE crystals and the increase of amorphous phases. The results demonstrated that the presence of functionalized graphene had an effective role in reducing crystallinity. Furthermore, the thermal and mechanical stability of the samples were corroborated through thermogravimetric analysis (TGA) and tensile tests, respectively. Notably, the samples exhibited adequate ionic conductivity at room temperature, with the highest ionic conductivity of 5.2 × 10-5 S·cm-1 observed for 2%wt of FGO in SPE (SPE/FGO(2)).

Effect of age on regulation of human osteoclast differentiation.

Human skeletal aging is characterized as a gradual loss of bone mass due to an excess of bone resorption not balanced by new bone formation. Using human marrow cells, we tested the hypothesis that there is an age-dependent increase in osteoclastogenesis due to intrinsic changes in regulatory factors [macrophage-colony stimulating factor (M-CSF), receptor activator of NF-κB ligand (RANKL), and osteoprotegerin (OPG)] and their receptors [c-fms and RANK]. In bone marrow cells (BMCs), c-fms (r = 0.61, P = 0.006) and RANK expression (r = 0.59, P = 0.008) were increased with age (27-82 years, n = 19). In vitro generation of osteoclasts was increased with age (r = 0.89, P = 0.007). In enriched marrow stromal cells (MSCs), constitutive expression of RANKL was increased with age (r = 0.41, P = 0.049) and expression of OPG was inversely correlated with age (r = -0.43, P = 0.039). Accordingly, there was an age-related increase in RANKL/OPG (r = 0.56, P = 0.005). These data indicate an age-related increase in human osteoclastogenesis that is associated with an intrinsic increase in expression of c-fms and RANK in osteoclast progenitors, and, in the supporting MSCs, an increase in pro-osteoclastogenic RANKL expression and a decrease in anti-osteoclastogenic OPG. These findings support the hypothesis that human marrow cells and their products can contribute to skeletal aging by increasing the generation of bone-resorbing osteoclasts. These findings help to explain underlying molecular mechanisms of progressive bone loss with advancing age in humans.

Reduced osteoclastogenesis and RANKL expression in marrow from women taking alendronate.

Alendronate (AL) is commonly used for the prevention and treatment of osteoporotic fractures. Little is known about the effects of AL administration on osteoclast differentiation from human marrow progenitor cells. We used marrow discarded during orthopedic surgery to test the hypothesis that cultures of bone marrow-derived stem cells (BMCs) from subjects receiving AL (+AL) may differ from control subjects with respect to in vitro osteoclast differentiation and regulatory factors. The number of osteoclasts generated in BMC cultures from control subjects was 4.7-fold greater than that from +AL subjects (P = 0.015). RANKL expression in +AL BMCs was 57% of that in controls (P = 0.001), and OPG expression in +AL BMCs was greater than in controls (153%, P = 0.01). The mean RANKL/OPG ratio in BMCs was 0.65 ± 0.35 for +AL specimens and 1.28 ± 0.53 for controls (P = 0.031). In addition, we assessed the direct effect of AL on expression of RANKL and OPG in marrow stromal cells isolated from nine control women. Treatment with AL downregulated RANKL expression and upregulated OPG expression, with an average 50% decrease in RANKL/OPG ratio at 10(-7) M (P = 0.004). These results show that osteoclast differentiation is dysregulated in marrow isolated from +AL subjects. Furthermore, AL may inhibit human osteoclastogenesis by affecting the key regulatory genes in marrow cells.

Evaluation of the effects of CO2 laser on debonding of orthodontics porcelain brackets vs. the conventional method.

Debonding of ceramic brackets due to their high bond strength and low fracture toughness is one of the clinician's complications. The purpose of this study is to evaluate the effect of a laser on shear bond strength, site of debonding, and ARI index during debonding of ceramic brackets and then compare it to the conventional method used for this procedure. Thirty polycrystalline alumina (G & H Series, Germany) brackets were bonded to 30 intact extracted first and second maxillary premolars and stored in a 1% thymol solution. A chemically cured orthodontic composite resin (No-mix, Unitek, USA) was used for bonding the brackets to the enamel surface on all teeth. All brackets were positioned 4 mm from the incisal edge of the teeth with an orthodontic bracket-positioning device. Then the teeth with bonded brackets were embedded in auto-polymerized polymethylmethacrylate (2.2.3 cm) blocks using a special device to make their slots horizontally parallel. These 30 teeth were then divided into two subgroups: control or no-lased (n = 15) and super pulse CO(2) laser (n = 15). To characterize the peak of SBS in two groups, we used an Instron machine while its blade was moving at a constant speed of 1 mm/min. For evaluating the site of debonding and the adhesive remnant index (ARI index), a light microscope and the Photoshop program were used. Means and standard deviations of the SBS in two subgroups shows that in the control group, the teeth have definitely higher values in comparison to the experimental group. The results of the two groups drew no substantial differences with respect to the surface of debonding, which was mostly within the adhesive. However, observing the results of ARI presented a significant distinction between the control and experimental group. This index denoted that the debonding site in the control group was closer to the enamel adhesive interface and, consequently, the rate of enamel damage in this group would be greater. The present study shows that a CO(2) laser has the potential to replace the conventional method for debonding ceramic brackets due to less debonding force and more adhesive remnant index on the tooth surface.

Implant placement in patients with oral bisphosphonate therapy: a case series.

BACKGROUND: Although the effect of bisphosphonates on dental implant osseointegration is not clear, dental implant failures attributable to oral bisphosphonate therapy have been reported in patients with osteoporosis. PURPOSE: The aim of this study was to evaluate implant survival in patients with a history of bisphosphonate therapy in a retrospective survey. MATERIALS AND METHODS: A total of 46 ITI implants placed in 21 osteoporotic patients (females; average age 53 years, range 42-79 years) were evaluated with regard to probing depth, mobility, thread exposure, and bleeding on probing. All patients were under oral bisphosphonate therapy. RESULTS: None of implants showed mobility and all patients could be considered free from peri-implantitis. Time of bisphosphonate therapy before and after implant insertion showed no statistically significant influence on PD, BOP, and TE. Likewise, implant location, prosthetic type, and opposing dentition had no statistically significant influence on the clinical and radiological parameters of implants. CONCLUSION: Within the limitations of this study, it could be concluded that neither being on oral bisphosphonate treatment before implant placement nor starting bisphosphonate therapy after implant installation might jeopardize the successful osseointegration and clinical and radiographic condition of the implants.

Ameloblastoma associated with the nevoid basal cell carcinoma (Gorlin) syndrome.

Nevoid basal cell carcinoma syndrome (NBCCS) is an autosomal dominant disorder characterized by a wide range of clinical signs and symptoms. The major criteria for the diagnosis are multiple cutaneous basal cell carcinomas, multiple odontogenic keratocysts of the jaw, palmar and plantar pits, and skeletal abnormalities. Here, we report an unusual case of NBCCS in a 68-year-old woman with late onset of clinical signs and symptoms and with an associated ameloblastoma. Only 4 other cases of this unusual association have been reported.

Effect of fluoride varnish on enamel demineralization around brackets: an in-vivo study.

INTRODUCTION: Even with advances in materials and techniques, demineralization around brackets during orthodontic treatment continues to be a problem. The purpose of this in-vivo study was to evaluate the effect of a fluoride varnish on enamel demineralization adjacent to bonded brackets. METHODS: Fifteen patients who needed at least 2 premolars extracted for orthodontic reasons were selected. In each patient, 1 premolar was considered the test tooth, and the other was the control. Brackets were bonded, and T-loops were engaged on all premolars, but only the test teeth received fluoride varnish. The premolars were extracted after 85 to 95 days, and buccolingual sections 50 to 70 microm in thickness were evaluated with polarized light microscopy. The mean depth of demineralization in each lesion was measured 3 times on photographs by an operator blinded to the groups (intraclass correlation of the 3 measurements was 0.988). RESULTS: The mean lesion depths were 57.0 +/- 5.5 microm in the test group and 94.3 +/- 6.7 microm in the control group. There was significant reduction (approximately 40%) in depth of demineralization in the test group (P <.001). CONCLUSIONS: Fluoride varnish can be beneficial as a preventive adjunct in reducing demineralization adjacent to brackets.

Giant cell tumor of bone express p63.

p63 contributes to skeletal development and tumor formation; however, little is known regarding its activity in the context of bone and soft tissue neoplasms. The purpose of this study was to investigate p63 expression in giant cell tumor of bone and to determine whether it can be used to discriminate between other giant cell-rich tumors. Seventeen cases of giant cell tumor of bone were examined to determine the cell type expressing p63 and identify the isoforms present. Total RNA or cell protein was extracted from mononuclear- or giant cell-enriched fractions or intact giant cell tumor of bone and examined by RT-PCR or western blot, respectively. Immunohistochemistry was used to evaluate p63 expression in paraffin embedded sections of giant cell tumor of bone and in tumors containing multinucleated giant cells, including: giant cell tumor of tendon sheath, pigmented villonodular synovitis, aneurysmal bone cyst, chondroblastoma, and central giant cell granuloma. The mononuclear cell component in all cases of giant cell tumor of bone was found to express all forms of TAp63 (alpha, beta, and gamma), whereas only low levels of the TAp63 alpha and beta isoforms were detected in multinucleated cells; DeltaNp63 was not detected in these tumors. Western blot analysis identified p63 protein as being predominately localized to mononuclear cells compared to giant cells. This was confirmed by immunohistochemical staining of paraffin-embedded tumor sections, with expression identified in all cases of giant cell tumor of bone. Only a proportion of cases of aneurysmal bone cyst and chondroblastoma showed p63 immunoreactivity whereas it was not detected in central giant cell granuloma, giant cell tumor of tendon sheath, or pigmented villonodular synovitis. The differential expression of p63 in giant cell tumor of bone and central giant cell granuloma suggest that these two tumors may have a different pathogenesis. Moreover, p63 may be a useful biomarker to differentiate giant cell tumor of bone from central giant cell granuloma and other giant cell-rich tumors, such as giant cell tumor of tendon sheath and pigmented villonodular synovitis.

Autosomal dominant gigantiform cementoma associated with bone fractures.

Here, we report a family with gigantiform cementomas, bone fractures, and autosomal dominant inheritance. Lesions are composed of benign, lobulated, calcified masses resembling cementum. Identification of a COL1A2 mutation in one patient was a polymorphism of no pathological significance. The subject of gigantiform cementomas and the associated bone disorder is both confusing and complex. Reported familial instances indicate genetic heterogeneity with (1) osteopenia and bone fractures, (2) one form of osteogenesis imperfecta, and (3) a polyostotic diaphyseal bone disorder.

Histopathological evaluation of pulpotomy with Er,Cr:YSGG laser vs formocresol.

The purpose of this study was to histologically investigate whether pulpotomy with Er,Cr:YSGG laser is an acceptable alternative for formocresol. Pulpotomy of 48 dog's primary canine teeth was performed with formocresol or Er,Cr:YSGG laser. Histological evaluations on hematoxylin and eosin-stained pulp tissues were made by an optical microscope 7 or 60 days later. Statistical analysis was performed with Fisher's exact test, Mann-Whitney U test, and Student's t test. Seven days after pulpotomy, samples treated with laser had significantly favorable histological features in the following measures: continuity of odontoblastic layer (P<0.001), presence of hemorrhage (P<0.008), amount of inflammation (P<0.002), tissue necrosis (P<0.001), internal resorption (P<0.002), level of vascularization (P<0.002), and size of abscess (P<0.041). Similar results were observed 60 days after pulpotomy, except that the differences were not mostly significant due to natural exfoliation of 16 teeth. In conclusion, Er,Cr:YSGG laser system is an acceptable alternative for formocresol in pulpotomy of deciduous teeth.

Comparing the effects of root surface scaling with ultrasound instruments and Er,Cr:YSGG laser.

There are several studies done to show the comparability of laser scaling and root planing with routine methods. The most suitable wavelengths for such an application are reported as 2,940 and 2,780 nm. The superficial interactions of the current wavelength with root surface is investigated in this study to compare the crater and crack formation during the procedures between ultrasound and Er,Cr:yttrium-scandium-gallium garnet (YSGG; 2,780 nm) laser-treated teeth. Thirty human teeth with calculus on their root surface, which were extracted because of the severe periodontitis, were selected for this interventional in vitro study. Calculus area were divided into two equal parts: One of them was prepared for Er,Cr:YSGG (Biolase, Waterlase, USA) laser irradiation and the other one for ultrasound treatment (Dentsply cavitron, DENTSPLY International, USA). The Er,Cr:YSGG laser was specified as follows: pulse energy = 50 mJ, power = 1 W, wavelength = 2,780 nm, pulse repetition rate = 20 pulse per seconds, tip length = 6 mm, and tip diameter = 600 microm. Nineteen of the laser samples (95%) and eight of ultrasound ones (40%) out of 20 samples in each group had craters showing a statistical significant difference (p < 0.001). The number and depth of these craters are also evaluated. Thirteen samples of the laser cases (65%) and all samples of the ultrasound group showed cracks with significant differences (p = 0.008). In addition, the number and width of cracks in both groups are reported. As a general conclusion, the laser-treated samples show more craters but less cracks.

Effect of simvastatin administration on periodontitis-associated bone loss in ovariectomized rats.

BACKGROUND: Hydroxyl methylglutaryl-coenzyme A reductase inhibitors, so-called statins, have been widely used for hyperlipidemic patients. Recently, it has been reported that they promote bone formation. The purpose of this study was to evaluate the effect of simvastatin on ligature-induced bone resorption in the mandible of the ovariectomized rat. METHODS: Forty-nine rats were divided into seven groups; ligature was placed in all groups except group 7, which was considered the sham group: group 1 (N = 7), ovariectomy (OVX) plus simvastatin (10(-6) M); group 2 (N = 7), OVX plus simvastatin (3 x 10(-7) M); group 3 (N = 7), OVX plus simvastatin (10(-7) M); group 4 (N = 7), OVX plus normal saline; group 5 (N = 7), OVX group; group 6 (N = 7), ligature without OVX; and group 7 (N = 7), sham surgery without OVX and ligature. Simvastatin was administered subperiosteally in the buccal fold of the bottom right first molar twice a week during the study. Four weeks after insertion of the ligatures, the animals were sacrificed. Mandibles were removed for radiologic and histologic analysis. Bone density, bone loss (BL), and attachment loss were measured. Analysis of variance (ANOVA) was used to compare groups. RESULTS: Histologic analysis showed that the simvastatin groups developed significantly less periodontal breakdown (P <0.05). BL was less in the simvastatin experimental group, but there was not a significant statistical difference between the simvastatin groups (groups 1 through 3) and the experimental control groups (groups 5 and 6; P >0.05). CONCLUSION: Within the limits of this study, it can be concluded that simvastatin shows protective features against the impact of periodontitis on attachment apparatus and alveolar bone.

The effect of a constant electrical field on osseointegration after immediate implantation in dog mandibles: a preliminary study.

PURPOSE: The long time span between insertion of implants and functional rehabilitation often inconveniences patients. Accelerating bone growth around dental implants can shorten this time span. This in vivo study evaluated the effect of a constant electrical field on bone growth around dental implants. MATERIALS AND METHODS: Four mongrel dogs were used in this study. Sixteen dental implants were placed immediately after extraction of the first premolar and molar teeth. A constant electrical field (CEF) generator was placed in the mucoperiostal pouch created from the subperiostral dissection under the inferior border of the dog's mandible and connected to the experiment side fixtures. CEF provided 3 V of electrical potential during osseointegration. Histologic sections were stained with hematoxylin-eosin and observed under light microscopy. The sections were analyzed histomorphometrically to calculate the amount of newly formed bone. Statistical analysis was performed with SPSS 11.0 computer software (alpha= 0.05). RESULTS: At the end of the first stage of the osseointegration (90 days) CEF group sections showed enhanced growth of the trabeculae compared with the control group. Statistical analysis revealed significant differences between experimental and control groups. Bone contact ratio was statistically significant in the experimental group (p= 0.001). An increase in the local bone formation and bone contact ratio was observed with direct electrical stimulation of the implant and the bone area around the implant. CONCLUSION: Minimal direct electrical current, which can produce an electrical field around the implant, can increase the amount of bone formation and decrease the time of osseointegration.

The effects of loading time on osseointegration and new bone formation around dental implants: a histologic and histomorphometric study in dogs.

BACKGROUND: Immediate loading of dental implants has been introduced as a method of reducing implant treatment time without compromising its prognosis. In this research, the effects of loading time on the amount of bone-to-implant contact and bone formation around dental implants were evaluated histologically. METHODS: Three months prior to implantation, the lower premolar teeth of 15 dogs were extracted. Three or four dental implants were placed in the healed extraction sites for each dog (N = 48). Dividing the dogs into three groups, the implants were either loaded 48 hours or 1 week later with metallic or prefabricated acrylic crowns or were left unloaded until the time of sacrifice. Three months after implant insertion, the animals were sacrificed and samples were investigated to define the amount of bone-to-implant contact, lamellar and woven bone percentage, and local inflammation of the newly formed bone. RESULTS: No significant difference in the observed criteria was reported among the three groups (P >0.05); however, the unloaded group had the highest degree of bone-to-implant contact and the group loaded 48 hours after the primary implant insertion had the least. The prosthesis type had no significant effect on the implant success rate (P >0.05). The lamellar and woven bone percentage of newly formed bone also did not differ in the three groups (P >0.05). One implant from each group failed in this study. CONCLUSION: Loading time does not seem to significantly affect the degree of osseointegration and bone-to-implant contact and the composition of newly formed bone around dental implants.

Diagnostic value of silver nitrate staining for nucleolar organizer regions in selected head and neck tumors.

BACKGROUND: The present study is aimed to assess the usefulness of silver nitrate staining of nucleolar organizer regions (NORs) as a quantitative criterion for the diagnosis of selected head and neck tumors. MATERIALS AND METHODS: The silver nitrate staining technique was used on 195 paraffin blocks collected from 85 patients. The samples consisted of 21 squamous cell carcinoma (SCC) of larynx, 28 SCC of oral mucosa and 36 samples of most common salivary gland tumors. Mann-Whitney U-Test was used for data analysis. RESULTS: A significant difference was seen in the number of AgNOR dots between oral and laryngeal SCC with surrounding dysplastic and normal tissues (P < 0.001) and also between mucoepidermoid carcinoma and adenoid cystic carcinoma with pleomorphic adenoma and normal salivary gland tissue (P < 0.001). CONCLUSION: The silver nitrate staining for NORs is a useful method for aiding the diagnosis of malignant and dysplastic mucosal lesions and also malignant and benign salivary gland tumors.

A comparative study of white and grey mineral trioxide aggregate as pulp capping agents in dog's teeth.

Mineral trioxide aggregate (MTA) is widely used for different perforation repairs, root-end filling, pulp capping and many other endodontic procedures. Because of potential discoloration effect of gray MTA, white MTA has been introduced into endodontic treatment for the same purposes. This study examined the dental pulp responses in dogs to both types of MTA used as a pulp-capping agent. The pulps of 24 teeth of four male dogs were exposed with a No.1 round bur and capped with either gray or white MTA. Histologic analysis was performed one and 2 weeks after treatment. Calcified bridge could be seen 1 week after treatment with both types of MTA, with no significant differences between the two treatments.

Histopathologic comparison of normal and hyperplastic condyles.

OBJECTIVE: The aim of this study was to compare normal and hyperplastic mandibular condyles using two different histopathologic staining techniques. STUDY DESIGN: Nine cases of condylar hyperplasia and 13 normal cases were studied after hematoxylin and eosin and silver staining. RESULTS: There was a significant difference between the two groups in the thickness of the hyperplastic cartilage layer of condylar soft tissue (P = 0.017). Also, the number of argyrophilic nucleolar organizer regions was significantly higher in the condylar hyperplasia case group (P = 0.0001). No significant differences could be demonstrated in cartilage island frequency, penetration depth, and distribution in the cancellous bone of condyles. CONCLUSION: The thickness of the hyperplastic cartilage layer appears significantly increased in condylar hyperplasia. In addition, argyrophilic nucleolar organizer region count may be useful in histopathological identification of condylar hyperplasia.

The effect of prostaglandin E2 and calcium gluconate on orthodontic tooth movement and root resorption in rats.

Possible modifications in orthodontic tooth movement (OTM) and root resorption as a result of local injections of prostaglandin E2 (PGE2) alone and with calcium gluconate (Ca) formed the aim of the present study. Twenty-four 8-week-old male Wistar rats were selected and randomly divided into three groups of eight. Both quadrants of the upper jaws of the first group of animals were used; therefore this group comprised two groups: control and normal. The upper left first molars of these eight animals were not placed under orthodontic force and received no injection, to serve as the normal group, considered for root resorption comparison only. The control group had localized submucosal injections of normal saline on the buccal side of the upper right first molar. In the third group, 0.1 ml of 1 mg/ml PGE2 was injected at the same site and the fourth group received an intraperitoneal injection of 200 mg/kg Ca (10%) in addition to the PGE2. All the injections were performed on days 0 and 7. The orthodontic appliance consisted of a closed coil spring ligated to the upper right first molar and incisor, exerting a force of 60 g during the 21-day experimental period, after which the animals were sacrificed. Palatal halves were removed for histological examination and for calculation of the amount of root resorption. Statistical analysis of data showed a significant (P < 0.05) acceleration in OTM after PGE2 injection compared with the control group. The addition of Ca reduced OTM but a significant increase (P< 0.05) was still recorded. A significant difference (P < 0.05) in root resorption was only observed between the PGE2 and normal groups. The findings show the importance of calcium ions working in association with PGE2 in stabilizing root resorption while significantly increasing OTM.

A study of the relationship between ameloblastoma and human papilloma virus.

PURPOSE: The purpose of this study was to determine the relation of ameloblastoma with one of its probable etiologic factors, human papilloma virus (HPV). MATERIALS AND METHODS: This study was carried out in a retrospective, observational, and blind manner with information forms using an exact polymerize chain reaction. Fifty paraffinated blocks of ameloblastoma tumor were compared with 50 impacted third molar follicles. RESULTS: The results indicate that statistically the incidence of HPV positivity in the case group is significantly higher than that in the control group (P <.025). Furthermore, in determination of trace HPV type in HPV-positive samples, the incidence of type 6 HPV in the case group is significantly higher than that in the control group (P <.005). None of types 8, 11, 16, 18, 31, and 33 were observed. CONCLUSION: The results of this research conclude that HPV could be regarded as a possible etiologic factor of ameloblastoma.