cAMP and Pyk2 interact to regulate prostate cell proliferation and function.

In cultured prostate cancer cells cAMP blocks proliferation and induces neuroendocrine differentiation. Pyk2 expression inversely correlates with malignancy of prostate cancer. The aim of this study was to investigate the interaction between cAMP and Pyk2 in the prostate. EPN cells, a line derived from human normal prostate expressing Pyk2, and EPN-PKM3 cells, an EPN clone bearing a Pyk2 kinase-negative mutant, were adopted as model system. cAMP inhibited cell growth in both prostate cell lines, and activated Pyk2, but not ERK1/2, in EPN cells. cAMP treatment, abolished the activation of AKT1, an important component of the pro-survival pathway, in the EPN cells but not in EPN-PKM3 cells. Finally, upon cAMP treatment, EPN and EPN-PKM3 cells exhibited different expression patterns of HOX genes, an important network controlling cell identity. These data demonstrated for the first time that Pyk2 and cAMP interact in regulating prostate cell functions and in "keeping" prostate identity

Influence of air abrasion and sonic technique on microtensile bond strength of one-step self-etch adhesive on human dentin

The purpose of this in vitro study was to evaluate the microtensile bond strength of one-step self-etch adhesive to human dentin surface modified with air abrasion and sonic technique and to assess the morphological characteristics of the pretreated dentin surface. The occlusal enamel was removed to obtain a flat dentin surface for thirty-six human molar teeth. The teeth were randomly divided into three experimental groups (n = 12 per group), according to the pretreatment of the dentin: (1) control group, (2) air abrasion group, and (3) sonic preparation group. Microtensile bond strength test was performed on a universal testing machine. Two specimens from each experimental group were subjected to SEM examination. There was no statistically significant difference in bond strength between the three experimental groups (P > 0.05). Mean microtensile bond strength (MPa) values were 35.3 ± 12.8 for control group, 35.8 ± 13.5 for air abrasion group, and 37.7 ± 12.0 for sonic preparation group. The use of air abrasion and sonic preparation with one-step self-etch adhesive does not appear to enhance or impair microtensile bond strength in dentin

Implant adaptation of stock abutments versus CAD/CAM abutments: a radiographic and scanning electron microscopy study

Introduction. The study evaluated a null-hypothesis of no differences of fit between stock abutments and CAD/CAM titanium, gold sputtered and zirconia abutments when examined for radiographic adaptation and Scanning Electron Microcopy (SEM) at their inner aspect. The agreement between microscopic and radiographic fit was also assessed. Methods. Implants (Osseospeed, Astra Tech, Mölndal, Sweden) were connected to titanium abutments (Ti-design, Astra Tech, Mölndal, Sweden) (control group n=12), to stock zirconia abutments (Zir-design, Astra Tech) (group 1 n=12) and to third party zirconia abutments (Aadva Zr abutment, GC, Tokyo, Japan) as observed under SEM (JEOL JSM-6060LV, Tokyo, Japan). Two independent operators blindly evaluated the images, according to a three-score scale: perfect adaptation, no complete adaptation, and clear evidence of no adaptation. A Kruskal-Wallis test was applied to assess significant differences in adaptation scores between the groups. Results. All specimens showed precise SEM adaptation at all tested interfaces and no radiographically apparent gaps. No significant differences were found and therefore the null-hypothesis tested was accepted. Radiographic and SEM scores were in agreement. Discussion. CAD/CAM titanium, gold sputtered and zirconia abutments and third-part CAD/CAM zirconia abutments show an adaptation to Astra Tech implants that is comparable to that of stock titanium and zirconia abutments. Clinicians might be able to verify such adaptation with an x-ray. In-vivo studies would be needed to evaluate the clinical outcome of CAD/CAM abutments

Evaluation of the adhesion of fiber posts cemented using different adhesive approaches

The aim of this study was to investigate the adhesion of fiber posts cemented with luting agents that utilize three currently available adhesive approaches: etch-and-rinse, self-etch, and self-adhesive. Forty-two intact single-rooted human premolars were used in the study. Teeth were divided into six groups. In each group, a different resin cement with its adhesive system (if needed) and a fiber post were used. The groups were classified, according to the adhesive approach, into the following three categories. (i) Etch-and-rinse groups: Calibra resin cement/XPBond adhesive + self-curing activator (SCA)/RadiX Fiber Post (Dentsply Caulk), FluoroCore 2 core build-up material/XPBond + SCA/RadiX Fiber Post (Dentsply Caulk), and MultiCore Flow luting and core build-up material/Excite DSC adhesive/FRC Postec Plus fiber post (Ivoclar Vivadent). (ii) Self-etch group: Panavia F 2.0/ED primer (Kuraray)/RadiX Fiber Post (Dentsply Caulk). (iii) Self-adhesive groups: experimental self-adhesive cement/RadiX Fiber Post (Dentsply Caulk), and RelyX Unicem/RelyX Fiber Post (3M ESPE). The adhesion between the post and the root canal walls was assessed using the 'thin-slice' push-out test. In the test arrangement used, the self-etching approach may offer less favourable adhesion to root canal dentin in comparison with etch-and-rinse and self-adhesive approaches

Ablative potential of four different pulses of Er: YAG lasers and low-speed hand piece

Abstract Objective: The aim of the study was to evaluate the ablation rate of caries in dentin with fluorescence-feedback controlled Er:YAG, Variable Square Pulse technology (VSPt) based Er:YAG working in different pulse durations, and steel bur. Materials and methods: Sixty human molar teeth with caries in dentin, extracted for periodontal reasons, were selected for this study. All selected teeth were randomly divided into five groups, each containing twelve specimens: (1) group FFC, fluorescence feedback-controlled Er:YAG laser; (2) group SSP (super short pulse: 50 μs); (3) group MSP (medium short pulse; 100 μs); (4) group SP (short pulse; 300 μs); and (5) group SB, steel bur in a slow-speed hand piece. A profilometer was used to determine the volume of the ablated caries in dentin. The clinical and real ablation rates of caries in dentin were calculated. Two specimens from each experimental group were selected randomly and subjected to SEM examination. Results: The volumes of the ablated caries in dentin in the SSP and SB groups were statistically significantly different in comparison with other experimental groups (p<0.05). The clinical and real ablation rate of caries in dentin was the highest for the SSP group (0.15±0.05 and 0.17±0.05 mm(3)/sec, respectively) and statistically significantly different in comparison with the MSP and SB groups (p<0.05). The SB and FFC groups revealed a dentin surface with a smear layer and closed dentinal tubules on SEM micrographs. In the SSP, MSP, and SP groups, an irregular surface without a smear layer was found. Conclusions: Taking into consideration the experimental conditions of the present study, SSP was the most efficient in ablation of caries in dentin, providing a smear layer-free surface with open dentinal tubules

Post retentive ability of a new resin composite with low stress behaviour

Objectives: To assess by means of push-out test the post retentive potential of a new flowable resin composite with low polymerization stress. Methods: SureFil (R) SDR (TM) (Dentsply, S) was compared with the resin cement Calibra (Dentsply, C). S and C were used in combination with the adhesive XP Bond (Dentsply, XPB). In C group the Self-Cure Activator was mixed with XPB. The following types of fibre posts were luted into 30 extracted premolars: Radix Fiber Post (Dentsply, R), DT Light Post (RTD, LP), ER Dentin Post (Komet, ER), DT Light SL (VDW, SL), FibreKleer (Jeneric Pentron, F). Six posted roots per group were tested. Each root provided three to five 1 mm-thick slices. Measured push-out strengths were differentiated by post space level and statistically analysed (p < 0.05). The failure mode of each debonded specimen was assessed. Results: Cement type did not have a significant effect on post retention (p = 0.54). Post type was a significant factor for push-out strength (p < 0.001). LP exhibited significantly higher retentive strength than SL and F; push-out strengths of ER and R were significantly higher than those of F. Post retention was significantly influenced by post space level (p < 0.001). Significantly higher push-out strengths were recorded at the coronal third than at the middle and apical levels. The post-cement interaction was significant (p = 0.002). Posts luted with S most often failed at the cement-post interface. Conclusions: When the new flowable low-stress composite was used to lute fibre posts, similar retentive strengths to those of a marketed cement from the same manufacturer were achieved. Clinical significance: SureFil (R) SDR (TM), a flowable composite originally proposed for bulk filling of posterior restorations, exhibited post retentive strengths similar to those of a cement by the same manufacturer. With a relatively high filler load, yet a low curing stress, SureFil (R) SDR (TM) may be adequate for both post cementation and core build-up. (C) 2012 Elsevier Ltd. All rights reserved

Influence of air abrasion and sonic technique on microtensile bond strength of one-step self-etch adhesive on human dentin

The purpose of this in vitro study was to evaluate the microtensile bond strength of one-step self-etch adhesive to human dentin surface modified with air abrasion and sonic technique and to assess the morphological characteristics of the pretreated dentin surface. The occlusal enamel was removed to obtain a flat dentin surface for thirty-six human molar teeth. The teeth were randomly divided into three experimental groups (n = 12 per group), according to the pretreatment of the dentin: (1) control group, (2) air abrasion group, and (3) sonic preparation group. Microtensile bond strength test was performed on a universal testing machine. Two specimens from each experimental group were subjected to SEM examination. There was no statistically significant difference in bond strength between the three experimental groups (P > 0.05). Mean microtensile bond strength (MPa) values were 35.3 ± 12.8 for control group, 35.8 ± 13.5 for air abrasion group, and 37.7 ± 12.0 for sonic preparation group. The use of air abrasion and sonic preparation with one-step self-etch adhesive does not appear to enhance or impair microtensile bond strength in dentin

Microtensile bond strength evaluation of self-adhesive resin cement to zirconia ceramic after different pre-treatments

Purpose: To evaluate the influence of different surface treatments and metal primer application on bond strength of zirconia ceramic to a self-adhesive resin cement. Methods: 40 cylinder-shaped (empty set 12 x 5.25 mm high) of zirconia ceramic (Aadva Zirconia) were randomly divided into four groups (n= 10), based on the surface treatment to be performed: (1) Sandblasting with 125 mu m Al2O3 particles (S) (positive control); (2) Selective infiltration etching (SIE); (3) Experimental heated etching solution applied for 30 minutes (ST); (4) No treatment (C). Half of the zirconia specimens of each group received the application of Metal Primer II. Eight disks for each group were luted using a self-adhesive resin cement (G-Cem Automix) to composite overlays (Paradigm MZ100). After 24-hour storage (37 degrees C, 100% RH) bonded specimens were cut into microtensile sticks and loaded in tension until failure. Data were analyzed with two-way ANOVA and Games-Howell (P lt 0.05). Failure mode distribution was recorded and scanning electron microscopy (SEM) was used to examine the fractured microbars. The remaining cylinders of each group (n= 2) were used for SEM surface analysis. Results: Both surface treatments and Metal Primer IT application improved bond strength values (P lt 0.05). When Metal Primer II was not applied ST treatment achieved highest bond strength values (22.17 +/- 10.37 MPa). Sandblasting in combination with Metal Primer II enhanced bond strength values compared to the other groups (23.46 +/- 11.19 MPa). (Am J Dent 2012;25;269-275)