Surface profile characterization of prefabricated resin composite veneers following simulated abrasion. An in vitro study.

Background: The surface of resin composite veneers is susceptible to the effect of the oral environment and surface profile characterization of different veneer systems is of importance to the longevity and clinical performance of the materials. The aim of the present study was to evaluate surface profile properties, as defined by gloss and roughness parameters, of prefabricated resin composite veneers (PCV) and compare with a laboratory resin composite (LRC) system, following simulated abrasion. Material and Methods: Twenty eight composite veneers equally divided to a prefabricated composite veneer (PCV) system and a laboratory resin composite (LRC) (control group) were tested following abrasion under a toothbrush simulator. Alterations in gloss (ΔGloss) and roughness (ΔSa, ΔSz, ΔSci, ΔSdr) parameters were examined (after- before abrasion) using a glossmeter and a 3D-optical profilometer, respectively. Correlation matrices between ΔGloss and ΔRoughness parameters were sought across the two resin composite veneer groups. Results: Τhere was weak evidence that the PCV group exhibited less change in surface gloss after experimental abrasion (PCV vs LRC: mean difference ΔGloss in GU, (MD: -1.7; 95% CI: -3.3, -0.1; p=0.04). For the roughness parameters, ΔSci in nm3/nm2 (MD : 0.2; 95% CI: 0.1, 0.3; p=0.002) and ΔSdr in percentage (MD: 10.6; 95% CI: 3.7, 17.5; p=0.004), exhibited the most pronounced differences between the groups with strong evidence demonstrating greater changes for the PCV group compared to the LRC. No strong correlation pattern could be identified between changes in gloss and roughness parameters across the groups. Conclusions: After abrasion, both PCV and LCR showed an increase in surface gloss, while the PCV group demonstrated a rougher core surface profile than LRC. Key words:Prefabricated, resin composite, veneers, gloss, roughness.

Does Sterilization Affect the Performance of Single-Step Resin Composite Polishers?

(1) Background: Single-step polishers are used extensively for resin-composite polishing. The purpose of this study was to evaluate the effect of sterilization on their performance. (2) Methods: Optrapol Next Generation/Ivoclar-Vivadent, Jazz Supreme/SS White, Optishine Brush/Kerr and Jiffy Polishing Brush/Ultradent were used for polishing a nanohybrid resin composite (IPS Empress Direct/Ivoclar-Vivadent). Polishers (n = 40) were microscopically inspected before use. After polishing, surface roughness (Sa, Sz, Sdr, Sci) and gloss were determined. Polishers were subsequently sterilized and microscopically re-examined. The process was repeated four times on new samples (n = 200). Data were analyzed using the Friedman test and Wilcoxon post hoc test, at α = 0.05. (3) Results: Optrapol's performance improved after the first sterilization for Sa and gloss, whereas it declined after the fourth sterilization for Sa. Jazz's, improved after the second sterilization for Sa and gloss and after the third sterilization for Sdr. An improvement trend was observed for Optishine after the first sterilization, but not statistically significant. Sa, Sz, and gloss declined after the fourth sterilization. Jiffy's performance was inconsistent, with a trend of performance loss after the fourth sterilization. (4) Conclusions: Performance of all polishing systems improved after the initial sterilization, but deteriorated after the fourth sterilization cycle. However, their performance can be considered clinically acceptable for a longer period of use.

Is a Wiggling-Motion Modified Two-Step Impression Technique as Accurate as Conventional Techniques in Restorative Dentistry?

BACKGROUND: The purpose of this study was to evaluate dental impression accuracy of one-step and two-step techniques compared to a modified two-step technique. METHODS: Four impression techniques were compared: (1) a one-step double mix (DM) technique, (2) a cut-out (CO) technique, in which space relief was created using a blade and a laboratory bur, (3) a membrane (ME) technique, in which space relief was created by placing a PVC membrane on top of the putty material during the primary impression, and (4) a wiggling motion (WI) technique, in which PVC membrane was placed and additional wiggling movements were performed during the first 20 s when the primary impression was seated upon the master model (MM). Impressions were poured with type IV stone. Casts were scanned with a laboratory scanner and measurements were made for each cast using three-dimensional analysis software. RESULTS: All groups presented differences compared to MM group, in at least one intra-abutment distance. Groups DM and ME presented the most significant differences, in three and two distances, respectively, whereas CO and WI presented one significant different distance compared to MM. There were no differences between MM and the four techniques for inter-abutment distances. CONCLUSIONS: WI yielded similar results with CO technique. Both performed better than the other groups.

The impact of cryopreservation on both sperm HPV-negative and positive subtypes.

It is well known that various human papillomavirus (HPV) genotypes are present in semen specimens. Also, it has been demonstrated that sperm parameters are negatively affected when HPV infection is present in the sperm sample. Besides all these, the effect of cryopreservation on HPV sensitivity and resistance is not known. The aim of the present study is to evaluate first the prevalence of HPV and secondly to elucidate whether cryopreservation of sperm HPV-positive samples has any effect on the viability of HPV. For this purpose, a cohort of 78 sperm specimens was used from a respective number of patients. After giving informed consent, semen analysis was performed. Each sperm sample was divided into four equal aliquots. The first one (fresh) was evaluated for the prevalence of HPV, while the other three aliquots were cryopreserved by adding an equal quantity of cryoprotectant and plunged into the LN. Each of the three aliquots was thawed 3, 6, and 12 months later, respectively, so as to evaluate whether there is a time-resistance period of HPV prevalence. HPV infection was found to be in eleven sperm samples, demonstrating a 14.1% (11/78) HPV prevalence. Among the HPV-positive samples, six of them were high-risk and the remaining were low-risk genotypes. Moreover, the high-risk fresh samples demonstrated higher motility values than the low-risk samples (60% ± 2.7 vs 45.6% ± 3.7, p < .05), while semen volume in the high-risk samples was significantly lower than the respective volume in the low-risk samples (2.26 ± 0.2ml vs 3.5 ± 0.6ml, p < .05). Interestingly, cryopreservation of the HPV-positive samples resulted in the sustainability and time-resistance of HPV in all high-risk HPV-positive samples, something that was not the case with the low-risk HPV-positive samples. Conclusively, sperm samples infected with high-risk HPV, demonstrate lower sperm parameters and time-resistance activity during cryopreservation.

The fidelity of transcription in human cells.

To determine the error rate of transcription in human cells, we analyzed the transcriptome of H1 human embryonic stem cells with a circle-sequencing approach that allows for high-fidelity sequencing of the transcriptome. These experiments identified approximately 100,000 errors distributed over every major RNA species in human cells. Our results indicate that different RNA species display different error rates, suggesting that human cells prioritize the fidelity of some RNAs over others. Cross-referencing the errors that we detected with various genetic and epigenetic features of the human genome revealed that the in vivo error rate in human cells changes along the length of a transcript and is further modified by genetic context, repetitive elements, epigenetic markers, and the speed of transcription. Our experiments further suggest that BRCA1, a DNA repair protein implicated in breast cancer, has a previously unknown role in the suppression of transcription errors. Finally, we analyzed the distribution of transcription errors in multiple tissues of a new mouse model and found that they occur preferentially in neurons, compared to other cell types. These observations lend additional weight to the idea that transcription errors play a key role in the progression of various neurological disorders, including Alzheimer's disease.

Mutational profile of primary clear cell renal cell carcinoma predicts recurrence and potential candidacy for adjuvant immune checkpoint inhibition.

Background: The risk of recurrence after nephrectomy for primary clear cell renal cell carcinoma (ccRCC) is estimated in daily practice solely based on clinical criteria. The aim of this study was to assess the prognostic relevance of common somatic mutations with respect to tumor aggressiveness and outcomes of ccRCC patients after definitive treatment. Methods: Primary tumors from 37 patients with ccRCC who underwent radical nephrectomy were analyzed for presence of somatic mutations using a 15-gene targeted next-generation sequencing (NGS) panel. Associations to histopathologic characteristics and outcomes were investigated in the study cohort (n=37) and validated in The Cancer Genome Atlas (TCGA) ccRCC cohort (n=451). Results: VHL was the most frequently mutated gene (51%), followed by PBRM1 (27%), BAP1 (13%), SETD2 (13%), KDM5C (5%), ATM (5%), MTOR (5%), and PTEN (3%). One-third of patients did not have any somatic mutations within the 15-gene panel. The vast majority of tumors harboring no mutations at all or VHL-only mutations (51%) were more frequently of smaller size (pT1-2) and earlier stage (I/II), whereas presence of any other gene mutations in various combinations with or without VHL was enriched in larger (pT3) and higher stage tumors (III) (p=0.02). No recurrences were noted in patients with unmutated tumors or VHL-only mutations as opposed to three relapses in patients with non- VHL somatic mutations (p=0.06). Presence of somatic mutations in PBRM1, BAP1, SETD2, KDM5C, ATM, MTOR, or PTEN genes in 451 TCGA ccRCC patients was associated with a significantly shorter disease-free survival (DFS) compared to those with unaltered tumors (q=0.01). Conclusions: Preliminary findings from this ongoing study support the prognostic value of non- VHL mutations including PBRM1, BAP1, SETD2, KDM5C, ATM, MTOR, and PTEN in primary ccRCC tumors as surrogates of earlier recurrence and potential selection for adjuvant immune checkpoint inhibition.

Hypoxia-Inducible Factor-2-Altered Urothelial Carcinoma: Clinical and Genomic Features.

Background: Hypoxia is recognized as a key feature of cancer growth and is involved in various cellular processes, including proliferation, angiogenesis, and immune surveillance. Besides hypoxia-inducible factor 1-alpha (HIF-1α), which is the main mediator of hypoxia effects and can also be activated under normoxic conditions, little is known about its counterpart, HIF-2. This study focused on investigating the clinical and molecular landscape of HIF-2-altered urothelial carcinoma (UC). Methods: Publicly available next-generation sequencing (NGS) data from muscle-invasive UC cell lines and patient tumor samples from the MSK/TCGA 2020 cohort (n = 476) were interrogated for the level of expression (mRNA, protein) and presence of mutations, copy number variations, structural variants in the EPAS1 gene encoding HIF-2, and findings among various clinical (stage, grade, progression-free and overall survival) and molecular (tumor mutational burden, enriched gene expression) parameters were compared between altered and unaltered tumors. Results: 19% (7/37) of UC cell lines and 7% (27/380) of patients with muscle-invasive UC display high EPAS1 mRNA and protein expression or/and EPAS1 alterations. EPAS1-altered tumors are associated with higher stage, grade, and lymph node metastasis as well as with shorter PFS (14 vs. 51 months, q = 0.01) and OS (15 vs. 55 months, q = 0.01). EPAS1 mRNA expression is directly correlated with that of its target-genes, including VEGF, FLT1, KDR, DLL4, CDH5, ANGPT1 (q < 0.001). While there is a slightly higher tumor mutational burden in EPAS1-altered tumors (9.9 vs. 4.9 mut/Mb), they are enriched in and associated with genes promoting immune evasion, including ARID5B, SPINT1, AAK1, CLIC3, SORT1, SASH1, and FGFR3, respectively (q < 0.001). Conclusions: HIF-2-altered UC has an aggressive clinical and a distinct genomic and immunogenomic profile enriched in angiogenesis- and immune evasion-promoting genes.

Current Options for Second-Line Systemic Therapy in Metastatic Renal Cell Carcinoma.

Standard systemic therapy of advanced renal cell carcinoma (RCC) involves targeting angiogenesis, mainly through tyrosine kinase inhibitors (TKI) against the vascular endothelial growth factor receptor (VEGFR) pathway and targeting the immune checkpoints, namely, programmed death-1 (PD-1) or its ligand (PD-L1), and cytotoxic T-lymphocyte-associated protein 4 (CTLA4). With current strategies of combining these two approaches in the front-line setting, less is known about optimal selection of therapy upon development of resistance in the second and later lines of treatment for progressive disease. This review discusses currently available therapeutic options in patients who have progressive RCC after prior treatment with double immune check-point inhibitors (ICIs) or ICI-TKI combinations.

Chronic aryl hydrocarbon receptor activity phenocopies smoking-induced skeletal muscle impairment.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) patients exhibit skeletal muscle atrophy, denervation, and reduced mitochondrial oxidative capacity. Whilst chronic tobacco smoke exposure is implicated in COPD muscle impairment, the mechanisms involved are ambiguous. The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor that activates detoxifying pathways with numerous exogenous ligands, including tobacco smoke. Whereas transient AHR activation is adaptive, chronic activation can be toxic. On this basis, we tested the hypothesis that chronic smoke-induced AHR activation causes adverse muscle impact. METHODS: We used clinical patient muscle samples, and in vitro (C2C12 myotubes) and in vivo models (mouse), to perform gene expression, mitochondrial function, muscle and neuromuscular junction morphology, and genetic manipulations (adeno-associated virus-mediated gene transfer). RESULTS: Sixteen weeks of tobacco smoke exposure in mice caused muscle atrophy, neuromuscular junction degeneration, and reduced oxidative capacity. Similarly, smoke exposure reprogrammed the muscle transcriptome, with down-regulation of mitochondrial and neuromuscular junction genes. In mouse and human patient specimens, smoke exposure increased muscle AHR signalling. Mechanistically, experiments in cultured myotubes demonstrated that smoke condensate activated the AHR, caused mitochondrial impairments, and induced an AHR-dependent myotube atrophy. Finally, to isolate the role of AHR activity, expression of a constitutively active AHR mutant without smoke exposure caused atrophy and mitochondrial impairments in cultured myotubes, and muscle atrophy and neuromuscular junction degeneration in mice. CONCLUSIONS: These results establish that chronic AHR activity, as occurs in smokers, phenocopies the atrophy, mitochondrial impairment, and neuromuscular junction degeneration caused by chronic tobacco smoke exposure.

Renin-Angiotensin System Single Nucleotide Polymorphisms Are Associated with Bladder Cancer Risk.

The renin-angiotensin system (RAS), besides being a major regulator of blood pressure, is also involved in tumor angiogenesis. Emerging evidence suggests a correlation between the use of pharmacologic RAS inhibitors and a delay in urothelial bladder cancer (BC) progression. However, it is unknown whether RAS gene variants may predispose to the development of BC. This study examined the association of RAS single nucleotide polymorphisms (SNPs) including AT1R rs5186, AT2R rs11091046, REN rs12750834, ANG rs4762, and ANG rs699 with the risk of developing non-invasive BC. Peripheral blood samples from 73 patients with T1 urothelial BC (66 men, seven women) and an equal number of healthy subjects (control group) were collected. The TT genotype of the REN rs12750834 SNP (OR: 2.8 [1.3-6.05], p = 0.008) and to a lesser extent the presence of the T allele (OR: 2.3 [1.2-4.48], p = 0.01) conferred a higher risk of BC. The highest risk for BC within SNP carriers of the RAS system was associated with the presence of the CC genotype (OR: 17.6 [7.5-41.35], p < 0.001) and C allele (OR: 17.7 [8.8-35.9], p < 0.001) of the ANG rs699 SNP. The presence of the AT2R rs11091046 SNP, particularly the AA genotype, was associated with a protective effect against developing BC (OR: 0.268 [0.126-057], p < 0.001). In conclusion, these results support the clinical utility of RAS gene SNPs AT2R rs11091046, REN rs12750834, and ANG rs699 in the genetic cancer risk assessment of patients and families with BC.

Mitochondrial Mechanisms of Neuromuscular Junction Degeneration with Aging.

Skeletal muscle deteriorates with aging, contributing to physical frailty, poor health outcomes, and increased risk of mortality. Denervation is a major driver of changes in aging muscle. This occurs through transient denervation-reinnervation events throughout the aging process that remodel the spatial domain of motor units and alter fiber type. In advanced age, reinnervation wanes, leading to persistent denervation that accelerates muscle atrophy and impaired muscle contractility. Alterations in the muscle fibers and motoneurons are both likely involved in driving denervation through destabilization of the neuromuscular junction. In this respect, mitochondria are implicated in aging and age-related neurodegenerative disorders, and are also likely key to aging muscle changes through their direct effects in muscle fibers and through secondary effects mediated by mitochondrial impairments in motoneurons. Indeed, the large abundance of mitochondria in muscle fibers and motoneurons, that are further concentrated on both sides of the neuromuscular junction, likely renders the neuromuscular junction especially vulnerable to age-related mitochondrial dysfunction. Manifestations of mitochondrial dysfunction with aging include impaired respiratory function, elevated reactive oxygen species production, and increased susceptibility to permeability transition, contributing to reduced ATP generating capacity, oxidative damage, and apoptotic signaling, respectively. Using this framework, in this review we summarize our current knowledge, and relevant gaps, concerning the potential impact of mitochondrial impairment on the aging neuromuscular junction, and the mechanisms involved.

Extreme variation in testes size in an insect is linked to recent mating activity.

Ample sperm production is essential for successful male reproduction in many species. The amount of sperm a male can produce is typically constrained by the size of his testes, which can be energetically expensive to grow and maintain. Although the economics of ejaculate allocation has been the focus of much theoretical and empirical literature, relatively little attention has been paid to individual adult variation and plasticity at the source of sperm production, the testes themselves. We experimentally address this issue using the insect Narnia femorata Stål (Hemiptera: Coreidae). We established the metabolic cost of testicular tissue and then quantified variation in individual testes mass in response to multiple mate quality and quantity treatments. We uncovered extreme variation across individuals and considerable short-term effects of mating activity on testes dry mass. Importantly, the observed variation in testes mass was associated with notable fitness consequences; females paired with males with larger testes had greater hatching success. Overall, pairing with a female resulted in a 11% reduction in dry testes mass. Despite this apparent considerable mating investment, we found no evidence of strategic allocation to higher quality females or longer-term changes in testes mass. The dynamic nature of testes mass and its metabolic cost is vital to consider in the context of re-mating rates, polyandry benefits and general mating system dynamics both in this species and more broadly.

Dissecting the neuronal vulnerability underpinning Alpers' syndrome: a clinical and neuropathological study.

Alpers' syndrome is an early-onset neurodegenerative disorder often caused by biallelic pathogenic variants in the gene encoding the catalytic subunit of polymerase-gamma (POLG) which is essential for mitochondrial DNA (mtDNA) replication. Alpers' syndrome is characterized by intractable epilepsy, developmental regression and liver failure which typically affects children aged 6 months-3 years. Although later onset variants are now recognized, they differ in that they are primarily an epileptic encephalopathy with ataxia. The disorder is progressive, without cure and inevitably leads to death from drug-resistant status epilepticus, often with concomitant liver failure. Since our understanding of the mechanisms contributing the neurological features in Alpers' syndrome is rudimentary, we performed a detailed and quantitative neuropathological study on 13 patients with clinically and histologically-defined Alpers' syndrome with ages ranging from 2 months to 18 years. Quantitative immunofluorescence showed severe respiratory chain deficiencies involving mitochondrial respiratory chain subunits of complex I and, to a lesser extent, complex IV in inhibitory interneurons and pyramidal neurons in the occipital cortex and in Purkinje cells of the cerebellum. Diminished densities of these neuronal populations were also observed. This study represents the largest cohort of post-mortem brains from patients with clinically defined Alpers' syndrome where we provide quantitative evidence of extensive complex I defects affecting interneurons and Purkinje cells for the first time. We believe interneuron and Purkinje cell pathology underpins the clinical development of seizures and ataxia seen in Alpers' syndrome. This study also further highlights the extensive involvement of GABAergic neurons in mitochondrial disease.

Lotus SHAGGY-like kinase 1 is required to suppress nodulation in Lotus japonicus.

Glycogen synthase kinase/SHAGGY-like kinases (SKs) are a highly conserved family of signaling proteins that participate in many developmental, cell-differentiation, and metabolic signaling pathways in plants and animals. Here, we investigate the involvement of SKs in legume nodulation, a process requiring the integration of multiple signaling pathways. We describe a group of SKs in the model legume Lotus japonicus (LSKs), two of which respond to inoculation with the symbiotic nitrogen-fixing bacterium Mesorhizobium loti. RNAi knock-down plants and an insertion mutant for one of these genes, LSK1, display increased nodulation. Ηairy-root lines overexpressing LSK1 form only marginally fewer mature nodules compared with controls. The expression levels of genes involved in the autoregulation of nodulation (AON) mechanism are affected in LSK1 knock-down plants at low nitrate levels, both at early and late stages of nodulation. At higher levels of nitrate, these same plants show the opposite expression pattern of AON-related genes and lose the hypernodulation phenotype. Our findings reveal an additional role for the versatile SK gene family in integrating the signaling pathways governing legume nodulation, and pave the way for further study of their functions in legumes.

Pathogenic variants in HTRA2 cause an early-onset mitochondrial syndrome associated with 3-methylglutaconic aciduria.

Mitochondrial diseases collectively represent one of the most heterogeneous group of metabolic disorders. Symptoms can manifest at any age, presenting with isolated or multiple-organ involvement. Advances in next-generation sequencing strategies have greatly enhanced the diagnosis of patients with mitochondrial disease, particularly where a mitochondrial aetiology is strongly suspected yet OXPHOS activities in biopsied tissue samples appear normal. We used whole exome sequencing (WES) to identify the molecular basis of an early-onset mitochondrial syndrome-pathogenic biallelic variants in the HTRA2 gene, encoding a mitochondria-localised serine protease-in five subjects from two unrelated families characterised by seizures, neutropenia, hypotonia and cardio-respiratory problems. A unifying feature in all affected children was 3-methylglutaconic aciduria (3-MGA-uria), a common biochemical marker observed in some patients with mitochondrial dysfunction. Although functional studies of HTRA2 subjects' fibroblasts and skeletal muscle homogenates showed severely decreased levels of mutant HTRA2 protein, the structural subunits and complexes of the mitochondrial respiratory chain appeared normal. We did detect a profound defect in OPA1 processing in HTRA2-deficient fibroblasts, suggesting a role for HTRA2 in the regulation of mitochondrial dynamics and OPA1 proteolysis. In addition, investigated subject fibroblasts were more susceptible to apoptotic insults. Our data support recent studies that described important functions for HTRA2 in programmed cell death and confirm that patients with genetically-unresolved 3-MGA-uria should be screened by WES with pathogenic variants in the HTRA2 gene prioritised for further analysis.

Epilepsy due to mutations in the mitochondrial polymerase gamma (POLG) gene: A clinical and molecular genetic review.

We performed a systematic review of the clinical, molecular, and biochemical features of polymerase gamma (POLG)-related epilepsy and current evidence on seizure management. Patients were identified from a combined electronic search of articles using Ovid Medline and Scopus databases, published from January 2000 to January 2015. Only patients with a confirmed genetic diagnosis of POLG mutations were considered. Seventy-two articles were included for analysis. We identified 128 pathogenic variants in 372 patients who had POLG-related epilepsy. Among these, 84% of the cases harbored at least one of these pathogenic variants: p.Ala467Thr, p.Trp748Ser, and p.Gly848Ser. A bimodal distribution of disease onset was present in early childhood (<5 years) and adolescence; female patients had a later presentation than male patients (median age 4.00 vs. 1.83 years, p-value = 0.041). Focal-onset seizure including convulsive, myoclonus, and occipital seizures was common at the outset and was refractory to pharmacotherapy. We confirmed that homozygous pathogenic variants located in the linker region of POLG were associated with later age of onset and longer survival compared to compound heterozygous variants. In addition, biochemical and molecular heterogeneities in different tissues were frequently observed. POLG-related epilepsy is clinically heterogeneous, and the prognosis is, in part, influenced by the location of the variants in the gene and the presence of hepatic involvement. Normal muscle and fibroblast studies do no exclude the diagnosis of POLG-related mitochondrial disease and direct sequencing of the POLG gene should be the gold standard when investigating suspected cases.

Chemical, mechanical and biological properties of contemporary composite surface sealers.

OBJECTIVES: To evaluate the chemical, mechanical, and biological properties of modern composite surface sealers (CSS) having different compositions. METHODS: The CSS products tested were Biscover LV (BC), Durafinish (DF), G-Coat Plus (GC), and Permaseal (PS). The tests performed were: (A): degree of conversion (DC%) by ATR-FTIR spectroscopy; (B): thickness of O2-inhibition layer by transmission optical microscopy; (C): surface hardness, 10 min after irradiation and following 1 week water storage, employing a Vickers indenter (VHN); (D): color (ΔE*) and gloss changes (ΔGU) after toothbrush abrasion, using L*a*b* colorimetry and glossimetry; (E): accelerated wear (GC,PS only) by an OHSU wear simulator plus 3D profilometric analysis, and (F): cytotoxicity testing of aqueous CSS eluents on human gingival fibroblast cultures employing the methyl-(3)H thymidine DNA labeling method. Statistical analyses included 1-way (A, B, ΔE*, ΔGU) and 2-way (C, F) ANOVAs, plus Tukey post hoc tests. Student's t-test was used to evaluate the results of the accelerated wear test (α=0.05 for all). RESULTS: The rankings of the statistical significant differences were: (A) PS (64.9)>DF,BC,GC (56.1-53.9) DC%; (B) DF,PS (12.3,9.8)>GC,BC (5.2,4.8) µm; (C): GC (37.6)>BC,DF (32.6,31.1)>PS (26.6) VHN (10 min/dry) and BC,DF (29.3,28.7)>GC(26.5)>PS(21.6) VHN (1w/water), with no significant material/storage condition interaction; (D): no differences were found among GC,DF,BC,PS (0.67-1.11) ΔE*, with all values within the visually acceptable range and PS,BC (32.8,29.4)>GC,DF (19.4,12.9) ΔGU; (E): no differences were found between GC and PS in volume loss (0.10,0.11 mm(3)), maximum (113.9,130.5 µm) and mean wear depths (30.3,27.5 µm); (F): at 1% v/v concentration, DF showed toxicity (23% vital cells vs 95-102% for others). However, at 5% v/v concentration DF (0%) and BC (9%) were the most toxic, whereas GC (58%) and PS (56%) showed moderate toxicity. SIGNIFICANCE: Important chemical, mechanical, and biological properties exist among the CSS tested, which may affect their clinical performance.

Exploiting cannabinoid-induced cytotoxic autophagy to drive melanoma cell death.

Although the global incidence of cutaneous melanoma is increasing, survival rates for patients with metastatic disease remain <10%. Novel treatment strategies are therefore urgently required, particularly for patients bearing BRAF/NRAS wild-type tumors. Targeting autophagy is a means to promote cancer cell death in chemotherapy-resistant tumors, and the aim of this study was to test the hypothesis that cannabinoids promote autophagy-dependent apoptosis in melanoma. Treatment with Δ(9)-Tetrahydrocannabinol (THC) resulted in the activation of autophagy, loss of cell viability, and activation of apoptosis, whereas cotreatment with chloroquine or knockdown of Atg7, but not Beclin-1 or Ambra1, prevented THC-induced autophagy and cell death in vitro. Administration of Sativex-like (a laboratory preparation comprising equal amounts of THC and cannabidiol (CBD)) to mice bearing BRAF wild-type melanoma xenografts substantially inhibited melanoma viability, proliferation, and tumor growth paralleled by an increase in autophagy and apoptosis compared with standard single-agent temozolomide. Collectively, our findings suggest that THC activates noncanonical autophagy-mediated apoptosis of melanoma cells, suggesting that cytotoxic autophagy induction with Sativex warrants clinical evaluation for metastatic disease.

Effect of tooth-bleaching methods on gloss and color of resin composites.

OBJECTIVES: The purpose of the study was to evaluate gloss and color changes of resin composites after exposure to different bleaching agents. METHODS: Products used, were: Nite White ACP (10% carbamide peroxide gel), Crest Classic and Supreme Whitestrip (6.5% and 14% hydrogen peroxide strips, accordingly). A hybrid (Herculite XRV) and a nanohybrid (Premise) resin composite were exposed to the bleaching agents. Twenty-four disk-shaped specimens per composite were subjected to bleaching by each of the agents (n=8) for up to 2 weeks. Color changes using CIE-L*a*b* system (50:50% acceptability threshold: ΔE*=3.3) were recorded after 1 and 2 weeks bleaching cycles relative to baseline measurements. In addition, gloss measurements (in gloss units) were performed at the same bleaching intervals and gloss changes were calculated. RESULTS: All bleaching agents tested provided decrease in gloss of both composites after 2-week bleaching (p<0.05). No differences were detected among the three bleaching regimens, for up to 2-week application, in terms of color and gloss changes on both composites. After the 2-week bleaching period, hybrid composite presented higher gloss reduction (%) than nanohybrid regardless of the bleaching agent (p<0.05). Color change (ΔE*) was lower than 3.3 for all composite-bleaching agent combinations. After 1- and 2-week bleaching time, the nanohybrid composite provided higher color change than the hybrid under all bleaching procedures (p<0.05). No strong correlation was proved between color (ΔE*) and gloss changes caused by bleaching treatments. CONCLUSIONS: After 2-week bleaching cycles, composites showed significant gloss reduction (p<0.05). Color alteration was below the 50:50% acceptability threshold (ΔE*<3.3) and it was product-depended. There was no significant difference in color and gloss changes between the evaluated bleaching strips and 10% carbamide peroxide gel.

Use of a vacuum-formed plastic sheet to aid in transferring and bonding metal splints.

Mobile teeth with compromised periodontal support may shift from their unstressed position during clinical splinting procedures and be stabilized in an incorrect position, resulting in occlusal interferences and unnecessary adjustment. A technique is presented that can be helpful to splint mobile teeth with a metal device. Using a vacuum or pressure device to create a mold using a cast transfers the splint intraorally for bonding. This thermoplastic sheet maintains mobile teeth in the desired position during the splinting procedure.