Micro-tensile bond strength to bovine sclerotic dentine: Influence of surface treatment

Objective: The objective of this study was to evaluate the influence of the surface treatment and acid conditioning (AC) time of bovine sclerotic dentine on the micro-tensile bond strength (mu-TBS) to an etch and rinse adhesive system. Materials and method: Thirty-six bovine incisors were divided into six groups (n = 6): G1 sound dentine submitted to AC for 15 s; G2-G6 sclerotic dentine: G2-AC for 15 s; G3-AC for 30 s; G4-EDTA and AC for 15 s; G5-diamond bur and AC for 15 s; G6-diamond paste and AC for 15 s. An adhesive system was applied to the treated dentine surfaces followed by a hybrid composite inserted in increments and light cured. After 24 h storage in water at 37 degrees C, the specimens were perpendicularly cut with a low-speed diamond saw to obtain beams (0.8 mm x 0.8 mm cross-sectional dimensions) for mu-TBS testing. Data was compared by ANOVA followed by Tukey`s test (P <= 0.05). Results: The mean L-TBS was G1: 18.87 +/- 5.36 MPa; G2: 12.94 +/- 2.09 MPa; G3: 11.73 +/- 0.64 MPa; G4: 11.14 +/- 1.50 MPa; G5: 22.75 +/- 4.10 MPa; G6: 22.48 +/- 2.71 MPa. G1, G5 and G6 presented similar bond strengths significantly higher than those of all other groups. Conclusion: The surface treatment of sclerotic dentine significantly influenced the bond strength to an adhesive system. Mechanical treatment, either using a diamond bur or a diamond paste was able to improve bonding to bovine sclerotic dentine, reaching values similar to bonding to sound dentine. (C) 2008 Elsevier Ltd. All rights reserved.

Effect of recombinant human bone morphogenetic protein-7 (rhBMP-7) on the viability, proliferation and differentiation of osteoblast-like cells cultured on a chemically modified titanium surface

Aim: The aim of the present study was to assess the influence of the chemical characteristics and roughness of titanium surfaces on the viability, proliferation and differentiation of osteoblast-like cells cultured in a medium supplemented with recombinant human bone morphogenetic protein-7 (rhBMP-7). Material and methods: Osteo-1 cells were grown on titanium disks presenting with the following surfaces: (1) machined, (2) coarse grit-blasted and acid-attacked (SLA) and (3) chemically modified SLA (SLAmod) in the absence or presence of 20 ng/ml rhBMP-7 in culture medium. The viability and number of osteo-1 cells were evaluated after 24 h. Analyses of total protein content (TP) and alkaline phosphatase (AP) activity at 7, 14 and 21 days, collagen content at 7 and 21 days and mineralized matrix formation at 21 days were performed. Results: Cell viability (P=0.5516), cell number (P=0.3485), collagen content (P=0.1165) and mineralized matrix formation (P=0.5319) were not affected by the different surface configurations or by the addition of rhBMP-7 to the medium. Osteo-1 cells cultured on SLA surfaces showed a significant increase in TP at 21 days. The ALPase/TP ratio (P=0.00001) was affected by treatment and time. Conclusion: The results suggest that the addition of rhBMP-7 to the culture medium did not exert any effect on the viability, proliferation or differentiation of osteoblast-like cells grown on the different surfaces tested. All titanium surfaces analyzed allowed the complete expression of the osteoblast phenotype such as matrix mineralization by osteo-1 cells.

Roughness of Human Enamel Surface Submitted to Different Prophylaxis Methods

The purpose of this in vitro study was to evaluate alterations in the surface roughness and micromorphology of human enamel submitted to three prophylaxis methods. Sixty-nine caries-free molars with exposed labial surfaces were divided into three groups. Group I was treated with a rotary instrument set at a low speed, rubber clip and a mixture of water and pumice; group II with a rotary instrument set at a low speed, rubber cup and prophylaxis paste Herjos-F (Vigodent S/A Industria e Comercio, Rio de Janeiro, Brazil); and group III with sodium bicarbonate spray Profi II Ceramic (Dabi A dante Indtistrias Medico Odontologicas Ltda, Ribeirao Preto, Brazil). All procedures were performed by the same operator for 10 s, and samples were rinsed and stored in distilled water. Pre and post-treatment surface evaluation was completed using a surface profilometer (Perthometer S8P Marh, Perthen, Germany) in 54 samples. In addition, the other samples were coated with gold and examined in a scanning electron microscope (SEM). The results of this study were statistically analyzed with the paired t-test (Student), the Kruskal-Wallis test and the Dunn (5%) test. The sodium bicarbonate spray led to significantly rougher surfaces than the pumice paste. The use of prophylaxis paste showed no statistically significant difference when compared with the other methods. Based on SEM analysis, the sodium bicarbonate spray presented an irregular surface with granular material and erosions. Based on this study, it can be concluded that there was an increased enamel stuface roughness when teeth were treated with sodium bicarbonate spray when compared with teeth treated with pumice paste.

The role of surface sealants in the roughness of composites after a simulated toothbrushing test

Objectives: To evaluate the influence of two surface sealants (BisCover/Single Bond) and three application techniques (unsealed/conventional/co-polymerization) on the roughness of two composites (Filtek Z250/Z350) after the toothbrushing test. Methods: Seventy-two rectangular specimens (5 mm x 10 mm x 3 mm) were fabricated and assigned into 12 groups (n = 6). Each sample was subjected to three random roughness readings at baseline, after 100,000 (intermediate), and 200,000 (final) toothbrushing strokes. Roughness (R) at each stage was obtained by the arithmetic mean of the reading of each specimen. Sealant removal was qualitatively examined (optical microscope) and classified into scores (0-3). Data were analyzed by Student`s paired t-test, two-way ANOVA/Tukey`s test, and by Wilcoxon, Kruskal-Wallis and Miller`s test (alpha = 0.05). Results: Z250 groups at baseline did not differ statistically from each other. Unsealed Z350 at baseline had lower R values. All the unsealed groups presented gradual decrease in R from baseline to final brushing. From baseline to the inter-mediate stage, Z250 co-polymerized groups presented a significant reduction in R (score 3). Conventionally sealed groups had no significant changes in R (scores 2-0.8). From baseline to the intermediate stage, the conventionally sealed Z350 Single Bond group had an increase in R (score 1.5). In the final stage, all the conventionally sealed groups presented a reduction in R (scores 0.7-0). Co-polymerized Single Bond groups had a significant reduction in R (scores 2.5-2.7), and co-polymerized BisCover groups an increase in R (scores 2.8-3). Conclusions: At any brushing stage, sealed composites presented superior performance when compared with unsealed composites. (C) 2009 Elsevier Ltd. All rights reserved.

Effect of different surface treatments on the repair bond strength of indirect composites

Purpose: To evaluate the tensile bond strength of indirect composites repaired with different surface treatments and direct composites. Methods: 180 specimens were prepared with Targis, belleGlass HP and Sculpture indirect composites, light-activated and post-cured according to the manufacturers` recommendations. The specimens were stored in distilled water for 24 hours at 37 degrees C. The bonding surfaces were prepared with air abrasion, hydrofluoric acid or hydrofluoric acid followed by a neutralizing solution. All the treated surfaces were subject to the application of a silane and a bonding agent before the repair procedures with Tetric Ceram and Tetric Flow for the Targis specimens, Herculite XRV and Revolution for the belleGlass HP specimens and Sculp-It and Flow-It for Sculpture specimens. The tensile bond strength tests were carried out using a universal testing machine at cross-head speed of 0.5 mm/minute. The type of fracture was observed under a light microscope at x40 magnification. Data were analyzed by a two-way ANOVA and Tukey`s post-hoc tests (P<0.05). Results: Targis showed a statistically higher repair bond strength than belleGlass HP and Sculpture, which were not significantly different from each other. Air abrasion increased the repair bond strength of belleGlass HP and Sculpture. For Targis, all the surface treatments resulted in similar repair bond strength. The different viscosity of repair composites did not affect the repair of indirect composites. Fractured surfaces showed mostly adhesive failures, mainly with hydrofluoric acid treatment.

In vitro wear, surface roughness and hardness of propanal-containing and diacetyl-containing novel composites and copolymers based on bis-GMA analogs

Objective. To evaluate the effect of two additives, aldehyde or diketone, on the wear, roughness and hardness of bis-GMA-based composites/copolymers containing TEGDMA, propoxylated bis-GMA (CH(3)bis-GMA) or propoxylated fluorinated bis-GMA (CF(3)bis-GMA). Methods. Fifteen experimental composites and 15 corresponding copolymers were prepared combining bis-GMA and TEGDMA, CH3bis-GMA or CF3bis-GMA, with aldehyde (24mol% and 32 mol%) or diketone (24 mol% and 32 mol%) totaling 30 groups. For composites, hybrid treated filler (barium aluminosilicate glass/pyrogenic silica; 60 wt%) was added to monomer mixtures. Photopolymerization was affected by 0.2 wt% each of camphorquinone and N,N-dimethyl-p-toluidine. Wear (W) test was conducted in a toothbrushing abrasion machine (n = 6) and quantified using a profilometer. Surface roughness (R) changes, before and after abrasion test, were determined using a rugosimeter. Microhardness (H) measurements were performed for dry and wet samples using a Knoop microindenter (n = 6). Data were analyzed by one-way ANOVA and Tukey`s test (alpha = 0.05). Results. Incorporation of additives led to improved W and H values for bis-GMA/TEGDMA and bis-GMA/CH(3)bis-GMA systems. Additives had no significant effect on the W and H changes of bis-GMA/CF(3)bis-GMA. With regard to R changes, additives produced decreased values for bis-GMA/CH3bis-GMA and bis-GMA/CF3bis-GMA composites. Bis-GMA/TEGDMA and bis-GMA/CH(3)bis-GMA copolymers with additives became smoother after abrasion test. Significance. The findings correlate with additives ability to improve degree of conversion of some composites/copolymers thereby enhancing mechanical properties. Published by Elsevier Ltd on behalf of Academy of Dental Materials

Growth factors and cytokines modulate gene expression of cell-surface proteoglycans in human periodontal ligament cells

Cell-surface proteoglycans have been known to be involved in many functions including interactions with components of the extracellular microenvironment, and act as co-receptors which bind and modify the action of various growth factors and cytokines. The purpose of this study was to determine the regulation by growth factors and cytokines on cell-surface proteoglycan gene expression in cultured human periodontal ligament (PDL) cells. Subconfluent, quiescent PDL cells were treated with various concentrations of serum, bFGF, PDGF-BB, TGF-beta1, IL-1 beta, and IFN-gamma. RT-PCR technique was used, complemented with Northern blot for syndecan-1, to examine the effects of these agents on the mRNA expression of five cell-surface proteoglycans (syndecan-1, syndecan-2, syndecan-4, glypican and betaglycan). Syndecan-1 mRNA levels increased in response to serum, bFGF and PDGF-BB, but decreased in response to TGF-beta1, IL-1 beta and IFN-gamma. In contrast, syndecan-2 mRNA levels were upregulated by TCF-beta1 and IL-1 beta stimulation, but remained unchanged with the other agents. Betaglycan gene expression decreased in response to serum, but was upregulated by TCF-beta1 and unchanged by the other stimulants. Additionally, syndecan-4 and glypican were not significantly altered in response to the regulator molecules studied, with the exception that glypican is decreased in response to IFN-gamma. These data demonstrate that the gene expression of the five cell-surface proteoglycans studied is differentially regulated in PDL cells lending support to the nation of distinct functions for these cell-surface proteoglycans. (C) 2001 Wiley-Liss, inc.

Cell-surface proteoglycan expression by lymphocytes from peripheral blood and Gingiva in health and periodontal disease

Cell-surface proteoglycans are involved in lymphocyte migration and activation. This study investigated the expression of syndecan-1, syndecan-4, and glypican in peripheral blood lymphocytes and by lymphocytes in variously inflamed periodontal tissues. Gingival specimens from healthy, gingivitis, or chronic periodontitis sites were stained by means of antibodies against B- and T-lymphocytes and also syndecan-1, syndecan-4, and glypican. Syndecan-1 expression by peripheral blood mononuclear cells (PBMC) from healthy, gingivitis, and chronic periodontitis subjects was assessed by flow cytometry. Syndecan-1 was expressed by B-cells/plasma cells but not T-cells in both gingivitis and chronic periodontitis lesions, Both B-cells/plasma cells and T-cells in gingivitis and chronic periodontitis expressed syndecan-4. Glypican was expressed only by macrophages. Stimulation of PBMC with mitogens and growth factors modulated syndecan-1 expression in both the T- and B-cells. Thus, cell-surface proteoglycan expression by lymphocytes in periodontal inflammation is cell-type-specific and may be modulated by inflammation.

Influences of surface and solvent on retention of HEMA/mixture components after evaporation

Objectives: This study examined the retention of solvents within experimental HEMA/solvent primers after two conditions for solvent evaporation: from a free surface or from dentine surface. Methods: Experimental primers were prepared by mixing 35% HEMA with 65% water, methanol, ethanol or acetone (v/v). Aliquots of each primer (50 mu l) were placed on glass wells or they were applied to the surface of acid-etched dentine cubes (2 mm x 2 mm x 2 mm) (n = 5). For both conditions (i.e. from free surface or dentine cubes), change in primers mass due to solvent evaporation was gravimetrically measured for 10 min at 51% RH and 21 degrees C. The rate of solvent evaporation was calculated as a function of loss of primers mass (%) over time. Data were analysed by two-way ANOVA and Student-Newman-Keuls (p < 0.05). Results: There were significant differences between solvent retention(%) and evaporation rate (%/min) depending on the solvent present in the primer and the condition for evaporation (from free surface or dentine cubes) (p < 0.05). For both conditions, the greatest amount of retained solvent was observed for HEMA/water primer. The rate of solvent evaporation for HEMA/acetone primer was almost 2- to 10-times higher than for HEMA/water primer depending whether evaporation occurred, respectively, from a free surface or dentine cubes. The rate of solvent evaporation varied with time, being in general highest at the earliest periods. Conclusions: The rate of solvent evaporation and its retention into HEMA/solvent primers was influenced by the type of the solvent and condition allowed for their evaporation. (C) 2009 Elsevier Ltd. All rights reserved.

Coupling of composite resin cements to quartz fiber posts: A comparison of industrial and ""chairside"" treatments of the post surface

Purpose: To evaluate the influence of surface treatments on microtensile bond strength of luting resin cements to fiber posts. Materials and Methods: Forty-two quartz fiber posts (Light Post, RTD) were divided into 7 groups (n = 6) according to the surface treatment. I and 11: experimental patented industrial treatment consisting of zirconium oxide coating and silanization (RTD); III: industrial treatment followed by adhesive application (XPBond, Dentsply Caulk); IV: adhesive (XPBond); V: adhesive (Prime&Bond NT, Dentsply Caulk); VI: silane (Calibra Silane, Dentsply Caulk); VII: no treatment. Adhesives were used in the self-curing mode. Two cements (Sealbond, RTD - group 1, and Calibra, Dentsply Caulk - groups 11 to VII) were applied on the posts to produce cylindrical specimens. Post/cement interfaces were evaluated under SEM. The surface of the industrially coated posts was examined using energy dispersive analysis by x-ray. Cylinders were cut to obtain microtensile sticks that were loaded in tension at a crosshead speed of 0.5 mm/min until failure. Statistical analysis was performed using Kruskal-Wallis analysis of variance followed by Dunn`s multiple range test for post-hoc comparisons (p < 0.05). Weibull analysis was also performed. Results: The post/cement bond strength was significantly higher on fiber posts treated industrially (I: 23.14 +/- 8.05 MPa; II: 21.56 +/- 7.07 MPa; III: 22.37 +/- 7.00 MPa) or treated with XPBond adhesive (IV: 21.03 +/- 5.34 MPa) when compared to Prime&Bond NT application (V: 14.05 +/- 5.06 MPa), silanization (VI: 6.31 +/- 4.60 MPa) or no treatment (VII: 4.62 +/- 4.31) of conventional fiber posts (p < 0.001). Conclusion: The experimental industrial surface treatment and the adhesive application enhanced fiber post to resin cement interfacial strength. Industrial pretreatment may simplify the clinical luting procedure.

Human osteoblastic cell response to a Ca- and P-enriched titanium surface obtained by anodization

The aim of the present study was to evaluate the in vitro osteogenic potential of subcultured human osteoblastic cells derived from alveolar bone on a titanium (Ti) surface produced by an anodized alkali treatment (BSP-AK). Primary osteoblastic cells were subcultured on BSP-AK and machined Ti discs (control) and grown for periods of up to 21 days under osteogenic conditions. Morphologic and biochemical methods were used to assess important parameters of in vitro bone-like tissue formation. Although no major differences were observed between the BSP-AK and the control Ti surface in terms of cell attachment and mineralized matrix formation, a significant increase in cell population, ALP activity, and collagen content was detected in cultures on BSP-AK surface. Our results demonstrate that human osteoblastic cells are sensitive to the BSP-AK-modified Ti surface during the transitional stage between the end of the proliferative phase and the onset of the differentiation /matrix maturation ones. Together with the good mechanical properties exhibited by the Ca- and P- coating, our findings suggest that BSP-AK treatment could be useful for the development of a new surface for dental and orthopedic implants. (c) 2008 Wiley Periodicals, Inc.J Biomed Mater Res 88A: 841-848, 2009

Development of the osteoblastic phenotype in human alveolar bone-derived cells grown on a collagen type I-coated titanium surface

The aim of this study was to evaluate the development of the osteoblastic phenotype in human alveolar bone-derived cells grown on collagen type I-coated titanium (Ti) surface (Col-Ti) obtained by plasma deposition acrylic acid grafting compared with machined Ti (M-Ti). Osteoblastic cells were cultured until subconfluence and subcultured on Col-Ti and M-Ti for periods of up to 21 days. Cultures grown on Col-Ti and M-Ti exhibited similar cell morphology. Cell adhesion, total protein content, and alkaline phosphatase (ALP) activity were not affected by Ti surface modification in all evaluated periods. Growth analyses indicated that there were significantly more cells in cultures grown on Col-Ti at day 3. Runt-related transcription factor 2 (Runx2), osteopontin (OPN), and osteoprotegerin (OPG) mRNA expression of cells subcultured on Col-Ti was higher, whereas collagen type I (COL) was lower compared with M-Ti. Ti surface modification neither affected the osteocalcin (OC), ALP and receptor activator of NF-kappa B ligand (RANKL) mRNA expression nor the calcium content extracted from mineralized matrix. These results demonstrated that Col-Ti favours cell growth during the proliferative phase (day 3) and osteoblastic differentiation, as demonstrated by changes in mRNA expression profile during the matrix mineralization phase (day 14), suggesting that this Ti surface modification may affect the processes of bone healing and remodelling. To cite this article:Assis AF, Beloti MM, Crippa GE, de Oliveira PT, Morra M, Rosa AL. Development of the osteoblastic phenotype in human alveolar bone-derived cells grown on a collagen type I-coated titanium surface.Clin. Oral Impl. Res. 20, 2009; 240-246.doi: 10.1111/j.1600-0501.2008.01641.x.

High concentration of residual aluminum oxide on titanium surface inhibits extracellular matrix mineralization

In the present study we characterized titanium (Ti) surfaces submitted to different treatments and evaluated the response of osteoblasts derived from human alveolar bone to these surfaces. Five different surfaces were evaluated: ground (G), ground and chemical etched (G1-HF for 60 s), sand blasted (SB-Al2O3 particles 65 pm), sand blasted and chemical etched (SLA1-HF for 60 s and SLA2-HF for 13 s). Surface morphology was evaluated under SEM and roughness parameters by contact scanning instrument. The presence of Al2O3 was detected by EDS and the amount calculated by digital analyses. Osteoblasts, were cultured on these surfaces and it was evaluated: cell adhesion, proliferation, and viability, alkaline phosphatase activity, total protein content, and matrix mineralization formation. Physical and chemical treatments produced very different surface morphologies. Al2O3 residues were detected on SB and SLA2 surfaces. Only matrix mineralization formation was affected by different surface treatments, being increased on rough surface (SLA1) and reduced on surface with high amount of Al2O3 residues (SB). On the basis of these findings, it is possible to conclude that high concentration of residual Al2O3 negatively interfere with the process of matrix mineralization formation in contact with Ti implant surfaces. (C) 2008 Wiley Periodicals, Inc. J Biomed Mater Res 87A: 588-597, 2008

Immediate Effect of the Resilient Splint Evaluated Using Surface Electromyography in Patients with TMD

The aim of this study was to analyze the immediate effect of resilient splints through surface electromyography testing and to compare the findings with the electromyographic profiles of asymptomatic subjects. The participants were 30 subjects, 15 patients with TMD (TMD Group) and 15 healthy subjects (Control Group), classified according to Research Diagnostic Criteria (RDC/TMD) Axis I. A resilient occlusal splint was made for each patient in the TMD Group from two mm thick silicon to cover all teeth. The EMG examination was performed before and immediately after installing the splint. Three tests were performed as follows: 1. Maximum Voluntary Contraction (MVC) using cotton rolls (standards test); 2. MVC in maximal intercuspation position; and 3. MVC with the splint in position. The EMG signal was recorded for five seconds. EMG indices were calculated to assess muscle symmetry, jaw torque, and impact. There was a statistically significant difference when comparing the results among the study groups. The symmetry index values in the Control Group were higher than the TMD Initial Group and similar to the TMD Group after the installation of the splint. The index values of torque were higher in TMD Initial Group when compared with the Controls. Impact values were lower than normal values in the TMD Initial Group and restored upon installation of the splint. The resilient occlusal splints may be used as complementary or adjunctive treatment of temporomandibular disorders.

Ultrastructural Analysis of Radicular Dentine Surface Submitted to CO(2) Laser at Different Parameters

Background: There are no reported studies comparing different parameter settings of the CO(2) laser and irradiation direction considering their effect on the morphology of radicular dentine surface. Purpose: To evaluate the alterations of radicular dentine (cervical, middle, and apical thirds) irradiated with CO(2) laser at different potencies and irradiation directions. Study Design: Roots of 35 canines were prepared and randomly distributed according to the laser potency: GI: no laser treatment (control) (n = 5); GII, 2 W (n = 10); GIII: 4 W (n = 10); GIV: 6 W (n = 10). Each group (excepting GI) was divided in two subgroups according to the irradiation distance (n = 5): (A) parallel and (B) perpendicular to the root canal walls. The roots were splited longitudinally and analyzed by scanning electron microscopy in a qualiquatitative way. The scores were submitted to Kruskal-Wallis and Dunn`s tests. Results: No significant statistical differences were observed among root canal thirds (P > 0.05). The specimens irradiated with 2 W were statistically different (P < 0.05) from those irradiated with 4 and 6 W, which were statistically similar between themselves (P > 0.05). With 2, 4, and 6 W at in parallel irradiation and 2 W in perpendicular direction, the surface showed a fissured aspect. With 4 W in perpendicular direction and 6 W in parallel and perpendicular direction, surface was modified by laser action and exhibited fused areas. Conclusions: The intensity of the effects is dependent on the laser-irradiation dosimetries. Alterations were more intense when higher parameters were used. Microsc. Res. Tech. 72:737-743, 2009. (C) 2009 Wiley-Liss, Inc.