Bonding strength of silorane-based composite to Er-YAG laser prepared dentin.

The aim of this study was to investigate the shear bond strength of two adhesive systems to laser-irradiated dentin compared with their shear bond strength to bur-cut dentin as well as to evaluate the influence of composition and type of dental materials on shear bond strength. Thirty-two dentin specimens prepared from human third molars were divided into two groups and conditioned either with an Er:YAG laser machine or with a carbide bur. Two different adhesive systems (Silorane System Adhesive and Single Bond) were evaluated in the present study. After light curing of the adhesives, a Teflon mold was placed over the ring with the dentin sample and filled with the composite resins Filtek Silorane and Filtek Z250 combined with the appropriate adhesive systems. This procedure resulted in 32 cylindrical specimens (3 mm in diameter, 4 mm in height) being bonded to the dentin. The specimens were stored for 24 h at 37 °C in water and then were thermocycled. Shear bond strength testing was conducted by means of a universal testing machine and failure patterns were analyzed under a stereomicroscope. Two specimens of each fracture failure mode were randomly selected for SEM evaluation. Filtek Silorane present no statistically significant difference in shear bond strength compared with Filtek Z250, regardless of dentin treatment (p > 0.05). Additionally, the self-etching Silorane Adhesive System exhibited as good adhesive values as etch-and-rinse Single Bond, independently on dentinal substrate (p > 0.05). Specimens prepared by Er:YAG laser appear as receptive to adhesive procedures as conventional carbide bur-cut specimens (p > 0.05).

Vascular endothelial growth factor polymorphisms and clinical outcome in patients with metastatic breast cancer treated with weekly docetaxel.

The aim of the study was to evaluate the association of vascular endothelial growth factor (VEGF) genotypes with treatment efficacy in a phase II trial. This study evaluated weekly docetaxel, as first-line treatment for metastatic breast cancer. Existing data from in vitro and animal model experiments suggest that docetaxel at low doses has anti-angiogenic activity. DNA was extracted from blood samples of 86 patients participating in the trial. Genotyping was performed for selected single-nucleotide polymorphisms (SNPs; VEGF-2578, -1498, -1154, and +936). Moreover, due to the highly polymorphic nature of the studied areas, we were able to analyze additional registered SNPs. All candidate genotypes were evaluated for associations with overall survival (OS), progression-free survival (PFS) and response rate. The VEGF-1154 GG genotype was more frequent in patients not responding to treatment compared with responders (42.9% vs 0.0%, P=0.048). Moreover, the VEGF-2578 AA genotype was associated with longer PFS compared with CC (hazard ratio (HR)=0.40; 95% confidence interval (CI) 0.17-0.98; pairwise P=0.0457). Patients with the VEGF-1190 GG genotype demonstrated shorter PFS compared with those with the alternative genotypes (GA and AA) combined (HR=3.85; 95% CI: 1.20-12.50; P=0.0224). In addition, the VEGF-2551/-2534 homozygous del18bp and VEGF-2430/-2425 homozygous ins1bp genotypes were associated with worse PFS compared with no deletion and no insertion, respectively (HR=2.49; 95% CI: 1.02-6.07; pairwise P=0.0442 and HR=2.57; 95% CI: 1.05-6.27; pairwise P=0.0385, respectively). Furthermore, patients with the VEGF-1498 CC genotype exhibited longer median OS compared with those with the alternatives genotypes (CT and TT) combined (HR=0.27; 95% CI: 0.08-0.89; P=0.0311). In multivariate analysis, the VEGF-2578 AA genotype retained its significance (P=0.0220) for PFS. Our results support the association of specific VEGF genotypes with clinical outcome in patients with metastatic breast cancer treated with a potentially anti-angiogenic regimen, such as weekly docetaxel. However, current results should be validated prospectively in larger cohorts.

Cyclin D1, EGFR, and Akt/mTOR pathway. Potential prognostic markers in localized laryngeal squamous cell carcinoma.

INTRODUCTION: EGFR (epidermal growth factor receptor), cyclin D1 and Akt/mTOR pathways are active in head and neck cancer. The aim of this study was to explore biomarker expression, their correlations with clinicopathological parameters and their prognostic utility in a cohort of patients with localized squamous laryngeal carcinoma. PATIENTS AND METHODS: We assessed relative messenger RNA expression of EGFR, Akt1, 2, and 3, mTOR and CCND1, copy number variants of the EGFR and CCND1 genes and immunohistochemical protein expression of EGFR, p-Akt308, p-Akt473, pmTOR, PTEN, p53 and cyclin D1 in paraffin-embedded tissue samples of localized laryngeal carcinomas. RESULTS: In 289 patients with T3-4 (77.8%), node-negative (84.1%) tumors of the larynx, high EGFR and CCND1 mRNA correlated with no or ex-smoking, (p = 0.003 and p = 0.029, respectively), while low Akt3 mRNA correlated with alcohol abuse, N0 stage, total laryngectomy, and absence of neck dissection. At a median follow-up of 74.5 months, high mTOR mRNA expression was marginally associated with shorter disease-free survival (hazard ratio [HR] = 1.54; p = 0.093) and high Akt3 mRNA with shorter overall survival (HR = 1.49; p = 0.0786), in univariate analysis. In multivariate analysis, node-positive status, subglottic-transglottic location, surgery other than total laryngectomy and mTOR/CCND1 mRNA interaction with a hazard ratio of 2.16 (p value for interaction: 0.0010) were independent predictors of relapse, while node-positive status and subglottic-transglottic location were associated with higher risk for death. CONCLUSION: In localized laryngeal cancer, clinicopathological parameters and an interaction of high mTOR and CCND1 mRNA expression were found to be associated with poor patient outcome.

Effect of a Diode Laser (445 nm) on Polymerization Efficiency of a Preheated Resin Composite Used for Luting of Indirect Composite Restorations.

PURPOSE: The aim of this study was to evaluate the polymerization efficiency of a preheated resin composite used as a luting agent for indirect restorations light-cured by a blue diode laser (445 nm). METHODS: Bronze molds were used to prepare cylindrical specimens of a laboratory composite (Ceramage) with dimensions 2, 3, and 4 mm in height and 8 mm in diameter. The molds had additional height of 120 µm for the placement of the preheated resin composite. A nanohybrid resin composite (Enamel Plus HRi) was preheated at 55°C to use as a luting agent. Photopolymerization was followed for 20 seconds using three light sources: a diode laser emitting at 445 nm (SiroLaser Blue) and two light-emitting diode (LED) units (Bluephase Style and Valo). Degree of conversion (DC) of the preheated resin composite was evaluated using Fourier transform infrared spectroscopy. RESULTS: The results indicated that the main effects of the analysis were significant for both material thickness (p<0.001) and polymerization method (p<0.001). The preheated resin composite was not polymerized under 4-mm-thick specimens, independent of the light-curing unit. For 2-mm material thickness, there was no difference among the three light-curing units (p=0.383), while 3-mm Bluephase Style presented very low DC. CONCLUSIONS: Diode laser (445 nm) achieved better polymerization efficiency at the same fluence compared to the LED unit at 3-mm depth, implying a better mechanical behavior and potential improved adhesion of the luting material to dentin.

Induction chemotherapy followed by concomitant radiotherapy and weekly cisplatin versus the same concomitant chemoradiotherapy in patients with nasopharyngeal carcinoma: a randomized phase II study conducted by the Hellenic Cooperative Oncology Group (HeCOG) with biomarker evaluation.

BACKGROUND: Concomitant administration of radiation therapy (RT) and chemotherapy with cisplatin (CCRT) is considered standard treatment in patients with locally advanced nasopharyngeal cancer (LA-NPC). The role of induction chemotherapy (IC) when followed by CCRT in improving locoregional control remains controversial. PATIENTS AND METHODS: Totally, 141 eligible patients with LA-NPC were randomized to either three cycles of IC with cisplatin 75 mg/m(2), epirubicin 75 mg/m(2) and paclitaxel (Taxol) 175 mg/m(2) (CEP) every 3 weeks followed by definitive RT (70 Gy) and concomitant weekly infusion of cisplatin 40 mg/m(2) (investigational arm, 72 patients) or to the same CCRT regimen alone (control arm, 69 patients). RESULTS: Sixty-two patients (86%) received three cycles of IC. No difference between the arms was observed in the number of patients who completed RT (61 versus 64, P = 018). Overall and complete response rates were very similar in the two arms and so were 3-year progression-free and overall survival rates. Grade III or IV toxic effects from IC were infrequent, apart of alopecia. Mucositis, weight loss and leukopenia were the most prominent side-effects from CCRT. CONCLUSION: IC with three cycles of CEP when followed by CCRT did not significantly improve response rates and/or survival compared with that of CCRT alone.

Evaluation of Monomer Elution and Surface Roughness of a Polymer-Infiltrated Ceramic Network CAD-CAM Material After Er,Cr:YSGG Laser-assisted Tooth Bleaching.

PURPOSE: The aim of this in vitro study was to examine the effect of Er,Cr:YSGG laser-assisted tooth bleaching treatment on the elution of monomers and surface roughness of a hybrid computer-aided design-computer-aided manufacturing (CAD-CAM) material, and to compare it with a resin composite for direct restorations. METHODS AND MATERIALS: Forty specimens of a hybrid CAD-CAM material (Enamic) and forty of a conventional resin composite (Tetric) were fabricated and randomly divided into four groups (n=10). Half of the specimens of each material were stored in distilled water and the other half in artificial saliva for 7 days. At the end of this period, the storage medium was analyzed by high-performance liquid chromatography (HPLC), and the surface roughness parameters of the specimens were evaluated by optical imaging noncontact interferometric profilometry. Afterwards, half of the specimens of each tested material received a conventional in-office tooth bleaching treatment and the other half an Er,Cr:YSGG laser-assisted bleaching treatment, and then they were again incubated in distilled water and artificial saliva for an additional 7-day time period. At the end of this period, the effect of the bleaching treatments on elution of monomers and surface roughness of the tested materials was evaluated. RESULTS: Bisphenol A (BPA), urethane dimethacrylate (UDMA), triethylene glycol dimethacrylate (TEGDMA), and bisphenol A-glycidyl dimethacrylate (BisGMA) were eluted from the conventional resin composite into both the solutions tested. Only TEGDMA was eluted from the hybrid CAD-CAM material. However, no statistically significant differences were found among the surface roughness parameters of both materials. Both the conventional and Er,Cr:YSGG laser-assisted tooth bleaching treatments affected the monomer elution from the composite resin. However, there were no statistically significant differences (p<0.05) between the treatments. CONCLUSIONS: According to the results of this study, tooth bleaching with Er,Cr:YSGG laser or conventional technique is safe, even if the bleaching agent comes in contact with hybrid CAD-CAM restorations.

Why do residents choose the medical oncology specialty? Implications for future recruitment--results of the 2007 French Association of Residents in Oncology (AERIO) Survey.

BACKGROUND: The aim of this study was to analyze demography, motivation behind the choice of the medical oncology specialty, career plans, and the quality of training in medical oncology and to provide guidance to candidates for boosting the number of oncologists. METHODS: In 2007, the French Association of Residents in Oncology conducted a nationwide study of all medical oncology residents in France. RESULTS: The strongest factors that had influenced their decision to become a medical oncology specialist were an interest in medical oncology (98%), exposure to this branch of medicine during graduate training as a medical student (83%), interest in research (81%), and the diversity of the activity (75%). The mean score for the quality of training was 6 (0-10). More time for reading during working hours as well as for attending staff meetings and greater availability of teaching oncologists would improve the quality of training. The most popular career choice was working in a public hospital but most residents stated that they had not received adequate information about the different career plans. CONCLUSIONS: No data are available regarding how training in medical oncology is perceived. This study provides useful data for future policies to boost the number of oncologists.

Structural Integrity Evaluation of Large MOD Restorations Fabricated With a Bulk-Fill and a CAD/CAM Resin Composite Material.

AIMS: To evaluate the effect of two composite restorative techniques (direct bulk fill vs indirect CAD/CAM) on the fracture resistance and mode of fracture of extended mesio-occlusal-distal (MOD) cavity preparations. METHODS: Fifty-one sound human mandibular third molars were divided into three groups (n=17). Extended bucco-lingual MOD cavities were prepared. Teeth in group 1 were restored with a bulk-fill resin composite (Filtek Bulk-Fill Posterior Restorative), teeth in group 2 were restored with composite computer-aided design/computer-aided manufacturing (CAD/CAM) inlays (Lava Ultimate), and teeth in group 3 served as control and remained intact. All specimens were submitted to thermocycling, and a fracture resistance test was performed using a Universal testing machine (0.5 mm/min). Mode of fracture was classified into five types. One-way analysis of variance and the Duncan test were used to analyze the fracture load data at a significance level of α = 0.05. A chi-square test was used for the analysis of fracture mode between the restorative groups. RESULTS: Statistical analysis showed significant differences in fracture resistance among the experimental groups. The teeth restored with the bulk-fill composite exhibited lower fracture resistance (1285.3±655.0 N) when compared to the teeth restored with the composite CAD/CAM inlays (1869.8±529.4 N) (p<0.05). Mode of fracture showed the same distribution between the restorative groups. CONCLUSIONS: Although both types of restorations failed at loads larger than those found in the oral cavity, the CAD/CAM composite inlays increased the fracture resistance of teeth with large MOD cavities when compared to direct bulk-fill composite restorations. The majority of fracture types were intraorally repairable for both restorative techniques.

Fluoride release and recharging ability of new dental sealants.

AIM: This in vitro investigation was to evaluate the fluoride release and recharge abilities of three recently introduced dental fissure sealants (FS). METHODS: Three dental FS were assessed: Teethmate F-1 (Kuraray), Fissurit F (Voco), BeautiSealant (Shofu), and a conventional glass ionomer cement FX-II (Shofu) as a control. Eight cylindrical specimens (7 × 2 mm) of each material were made and immersed individually in 5 ml de-ionized water in plastic containers. Fluoride release of the tested materials was evaluated during the experimental period (28 days) utilising a fluoride ion-selective electrode. At the end of the test period, the specimens were soaked for 5 min in a fluoride solution (0.05 % NaF) and fluoride release was evaluated for the next 5 days. The data were statistically analysed using one-way ANOVA and Bonferroni post hoc test and the level of significance was preset at α = 0.05. RESULTS: The total fluoride release over the 28-day period for each material was: FX-II (408.6 ± 45.66 µg/cm(2)) > Teethmate F-1 (89.45 ± 12.32 µg/cm(2)) > Fissurit F (68.62 ± 8.72 µg/cm(2)) > BeautiSealant (33.32 ± 4.91 µg/cm(2)), (p < 0.05). After the re-fluoridation of the specimens with 0.05 % NaF solution the cumulative fluoride re-release during the 5-day period for each material was: FX-II (99.53 ± 13.21 µg/cm(2)) > Teethmate F-1 (9.76 ± 1.62 µg/cm(2)) > BeautiSealant (5.69 ± 0.89 µg/cm(2)) > Fissurit F (4.76 ± 0.72 µg/cm(2)), (p < 0.05). CONCLUSIONS: The three tested sealants exhibited different capabilities to release and uptake fluoride ions after re-fluoridation but significantly lower than the glass ionomer tested.

The evaluation of various restoration techniques on internal adaptation of composites in class v cavities.

Aim. The aim of this study was to evaluate the effect of different restoration techniques on the formation of internal microgaps between materials and dentin in class V restorations. Materials and Methods. Twenty-five extracted human premolars were prepared with standardized class V cavity outlines (3 mm × 2 mm × 2 mm). The cavities were randomly divided into 5 groups of 10 cavities each and restored according to manufacturer's instructions: Group 1: preheating (55°C) conventional composite (Filtek Z250), Group 2: flowable composite (Filtek Flow), Group 3: Filtek Flow + Filtek Z250 light-cured separately, Group 4: Filtek Flow + Filtek Z250 light-cured simultaneously, and Group 5 (control): Filtek Z250 at room temperature (23°C). The specimens were then thermocycled and cross-sectioned through the center of the restoration. Subsequently, impressions were taken, and epoxy resin replicas were made. The internal adaptation of the materials to the axial wall was analyzed under SEM. Results. The preheated Filtek Z250 (Group 1) showed better internal adaptation than the room temperature groups (P < 0.05). The combination of Filtek Flow with Filtek Z250 which was light-cured separately (Group 3) exhibited better internal adaptation than control group (P < 0.05). Conclusion. Different restoration techniques exhibit different behavior regarding internal adaptation to dentin after photopolymerization.