Mansuang Arksornnukit

The synergistic effect of TGF-β and 1,25-dihydroxyvitamin D3 on SPARC synthesis and alkaline phosphatase activity in human pulp fibroblasts

1,25(OH)2D3 and TGF-beta can influence the function and differentiation of dental pulp fibroblasts. In this study, we examined the effect of 1,25(OH)2D3 and TGF-beta on the synthesis of SPARC and ALP activity in human pulp fibroblasts. Two isoforms of SPARC, the 43 and 38 kDa, were detected in this cell type. TGF-beta increased the synthesis of SPARC about 2.5-fold after 3 days of treatment but had no effect on the ALP activity. On the contrary, 1,25(OH)2D3 increased ALP activity 2-fold but had no effect on SPARC. The combination of TGF-beta and 1,25(OH)2D3 significantly induced SPARC synthesis and ALP activity by 5 and 9 folds, respectively (P<0.05). This finding suggested the synergistic effect between TGF-beta and 1,25(OH)2D3 in dental pulp fibroblasts on the synthesis of SPARC and ALP activity. This interaction could influence the function and differentiation of dental pulp fibroblasts.

Effect of surface pretreatments on resin composite bonding to PEEK.

This study evaluated the effect of surface pretreatments on resin composite bonding to polyetheretherketone (PEEK). Four groups of surface pretreatment (no pretreatment, etched with 98% sulfuric acid, etched with piranha solution and sandblasting with 50 µm alumina) were performed on PEEK. Surface roughness, Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) analysis were examined. Shear bond strength (SBS) and interface characteristics were also evaluated after the specimens were bonded with resin materials. Two-way ANOVA analysis revealed significance on two main effects and interactions. Tukeys multiple comparisons test showed that the SBS of resin composite on PEEK were the highest in the group etched with 98% sulfuric acid and bonded with Heliobond(®) (p<0.05). All pretreatments produced similar spectra of FTIR patterns. SEM demonstrated porosities and pitting from chemical etching, which suggested a significant influence on the adhesion between PEEK and resin materials.

In vitro evaluation of the wear resistance of composite resin blocks for CAD/CAM

UNLABELLED The aim of the study was to investigate two- and three-body wear of CAD/CAM blocks. Four composite resins, one hybrid ceramic and one feldspar ceramic block material were examined. Six specimens each were tested in a ball-on-disc wear device fitted with a zirconia ball (50 N load, 1.2 Hz, 50 k cycles) in water for two-body and in poppy seed slurry for three-body wear evaluation. Volume loss after each 10 k cycle was quantified using a digital CCD microscope. STATISTICAL ANALYSIS ANOVA and Tukeys multiple comparisons (α=0.05). Two-body wear for composite resin blocks was small, hybrid ceramic and ceramic blocks showed larger volume loss. Threebody wear was very low for all materials. All CAD/CAM block materials investigated displayed low wear compared to previous data for direct posterior composites carrying out the same wear test. The block materials are considered suitable for fabrication of single full crown restorations on premolar teeth.

Pressure transmission and distribution under impact load using artificial denture teeth made of different materials

STATEMENT OF PROBLEM Pressure transmission and distribution under denture bases may be different depending on the material of the artificial denture teeth used. PURPOSE The purposes of this study were to evaluate pressure transmission and distribution under impact load using artificial denture teeth composed of different materials, and to examine the modulus of elasticity of the artificial denture teeth. MATERIAL AND METHODS The denture base specimens with artificial denture teeth made of 4 different materials (acrylic resin, microfilled composite resin, nanocomposite resin, and ceramic) were evaluated. Pressure transmission, distribution, and maximum pressure (n=10) were observed with pressure-sensitive sheets under an impact load. Modulus of elasticity of the artificial denture teeth (n=10) was measured by using an ultramicroindentation system. Data were statistically analyzed with 1-way ANOVA, followed by Tukey HSD and Tamhanes multiple range post hoc tests (alpha=.05). RESULTS Maximum pressure transmission observed from ceramic denture teeth was significantly higher than that of other groups (P<.001). Nanocomposite resin denture teeth presented the lowest pressure transmission, whereas a localized stress transmission area was observed in the ceramic denture teeth group. Significant differences in the modulus of elasticity were observed among the 4 types of artificial denture teeth (P<.001). CONCLUSIONS Pressure transmission and distribution varied among the denture tooth materials. Differences in the modulus of elasticity of each type of denture tooth were demonstrated.

Toothbrushing alters the surface roughness and gloss of composite resin CAD/CAM blocks.

This study investigated the surface roughness and gloss of composite resin CAD/CAM blocks after toothbrushing. Five composite resin blocks (Block HC, Cerasmart, Gradia Block, KZR-CAD Hybrid Resin Block, and Lava Ultimate), one hybrid ceramic (Vita Enamic), one feldspar ceramic (Vitablocs Mark II), one PMMA block (Telio CAD), and one conventional composite resin (Filtek Z350 XT) were evaluated. Surface roughness (Ra) and gloss were determined for each group of materials (n=6) after silicon carbide paper (P4000) grinding, 10k, 20k, and 40k toothbrushing cycles. One-way repeated measures ANOVA indicated significant differences in the Ra and gloss of each material except for the Ra of GRA. After 40k toothbrushing cycles, the Ra of BLO and TEL showed significant increases, while CER, KZR, ULT, and Z350 showed significant decreases. GRA, ENA, and VIT maintained their Ra. All of the materials tested, except CER, demonstrated significant decreases in gloss after 40k toothbrushing cycles.

Pressure transmission and distribution under denture bases using denture teeth with different materials and cuspal angulations.

STATEMENT OF PROBLEM Pressure transmission and distribution under denture bases may be variable depending on the different materials and cuspal angulations of denture teeth. PURPOSE The purpose of this study was to evaluate pressure transmission and distribution under impact load using denture teeth made with different materials and cuspal angulations. MATERIAL AND METHODS Three types (acrylic resin, microfilled composite resin, and ceramic) and 4 different cuspal angulations (0 degree, 20 degree, 33 degree, and 35 degree) of denture teeth were evaluated. Pressure transmission, distribution, and maximum pressure (n=10) were observed with pressure-sensitive sheets under an impact load. Data were statistically analyzed with 2-way ANOVA (α=.05) to determine significant interactions between denture tooth materials and cuspal angulations with respect to pressure transmission, followed by 1-way ANOVA (α=.05) to examine how materials and angulations jointly affected the pressure. Two 1-way ANOVAs were performed on the acrylic resin and ceramic denture teeth with the inclusion of 20-degree denture teeth groups. Tukey HSD and Tamhanes post hoc tests were used to evaluate data differences among groups. RESULTS Denture tooth materials and cuspal angulations had significant interactions with respect to average pressure (P<.001) and maximum pressure transmission (P=.007). Zero-degree denture teeth showed significantly lower average and maximum pressures than 33- and 35-degree denture teeth for all 3 denture tooth materials (P<.001). Denture teeth with greater cuspal angulations demonstrated significantly higher average pressure transmission for all ceramic denture teeth groups (P<.05). CONCLUSIONS Pressure transmission and distribution varied among denture teeth made of different materials and with different cuspal angulations. Cusped denture teeth presented significantly higher average pressure and maximum pressure transmission compared to 0-degree denture teeth.

Effects of different sulfuric acid etching concentrations on PEEK surface bonding to resin composite

This study evaluated the effects of surface pretreatment with different concentrations of sulfuric acid etching on surface properties and bonding between Polyetheretherketone (PEEK) and a resin composite. Six groups of surface pretreatment (no pretreatment, etched with 70, 80, 85, 90, and 98% sulfuric acid for 60 s) were treated on PEEK. Surface roughness, scanning electron microscopy (SEM) and atomic force microscopy (AFM) analyses were examined. Shear bond strength (SBS) and cross-sectional observations of the interfaces were performed. One-way ANOVA analysis revealed differences in surface roughness and SBS between groups. The 90 and 98% sulfuric acid etching significantly achieved the highest SBS (p<0.05). SEM and AFM demonstrated etched surfaces with wide and deep pores. The 90 and 98% sulfuric acid etching were suggested to be the optimal concentration to improve adhesion between PEEK and the resin composite.

Discoloration of various CAD/CAM blocks after immersion in coffee

Objectives This study evaluated color differences (ΔEs) and translucency parameter changes (ΔTPs) of various computer-aided design/computer-aided manufacturing (CAD/CAM) blocks after immersion in coffee. Materials and Methods Eight CAD/CAM blocks and four restorative composite resins were evaluated. The CIE L*a*b* values of 2.0 mm thick disk-shaped specimens were measured using the spectrophotometer on white and black backgrounds (n = 6). The ΔEs and ΔTPs of one day, one week, and one month immersion in coffee or water were calculated. The values of each material were analyzed by two-way ANOVA and Tukeys multiple comparisons (α = 0.05). The ΔEs after prophylaxis paste polishing of 1 month coffee immersion specimens, water sorption and solubility were also evaluated. Results After one month in coffee, ΔEs of CAD/CAM composite resin blocks and restorative composites ranged from 1.6 to 3.7 and from 2.1 to 7.9, respectively, and ΔTPs decreased. The ANOVA of ΔEs and ΔTPs revealed significant differences in two main factors, immersion periods and media, and their interaction except for ΔEs of TEL (Telio CAD, Ivoclar Vivadent). The ΔEs significantly decreased after prophylaxis polishing except GRA (Gradia Block, GC). There was no significant correlation between ΔEs and water sorption or solubility in water. Conclusions The ΔEs of CAD/CAM blocks after immersion in coffee varied among products and were comparable to those of restorative composite resins. The discoloration of CAD/CAM composite resin blocks could be effectively removed with prophylaxis paste polishing, while that of some restorative composites could not be removed.

Antifungal, optical, and mechanical properties of polymethylmethacrylate material incorporated with silanized zinc oxide nanoparticles

Background Fungal infected denture, which is typically composed of polymethylmethacrylate (PMMA), is a common problem for a denture wearer, especially an elderly patient with limited manual dexterity. Therefore, increasing the antifungal effect of denture by incorporating surface modification nanoparticles into the PMMA, while retaining its mechanical properties, is of interest. Aim of the study This study aimed to evaluate antifungal, optical, and mechanical properties of heat-cured PMMA incorporated with different amounts of zinc oxide nanoparticles (ZnOnps) with or without methacryloxypropyltrimethoxysilane modification. Materials and methods Specimens made from heat-cured PMMA containing 1.25, 2.5, and 5% (w/w) nonsilanized (Nosi) or silanized (Si) ZnOnps were evaluated. Specimens without filler served as control. The fungal assay was performed placing a Candida albicans suspension on the PMMA surface for 2 h, then Sabouraud Dextrose Broth was added, and growth after 24 h was determined by counting colony forming units on agar plates. A spectrophotometer was used to measure the color in L* (brightness), a* (red-green), b* (yellow-blue) and opacity of the experimental groups. Flexural strength and flexural modulus were determined using a three-point bending test on universal testing machine after 37°C water storage for 48 h and 1 month. Results The antifungal, optical, and mechanical properties of the PMMA incorporated with ZnOnps changed depending on the amount. With the same amount of ZnOnps, the silanized groups demonstrated a greater reduction in C. albicans compared with the Nosi groups. The color difference (ΔE) and opacity of the Nosi groups were greater compared with the Si groups. The flexural strength of the Si groups, except for the 1.25% group, was significantly greater compared with the Nosi groups. Conclusion PMMA incorporated with Si ZnOnps, particularly with 2.5% Si ZnOnps, had a greater antifungal effect, less color differences, and opacity compared with Nosi ZnOnps, while retaining its mechanical properties.

Pressure transmission area and maximum pressure transmission of different thermoplastic resin denture base materials under impact load

PURPOSES The purposes of the present study were to examine the pressure transmission area and maximum pressure transmission of thermoplastic resin denture base materials under an impact load, and to evaluate the modulus of elasticity and nanohardness of thermoplastic resin denture base. METHODS Three injection-molded thermoplastic resin denture base materials [polycarbonate (Basis PC), ethylene propylene (Duraflex), and polyamide (Valplast)] and one conventional heat-polymerized acrylic resin (PMMA, SR Triplex Hot) denture base, all with a mandibular first molar acrylic resin denture tooth set in were evaluated (n=6). Pressure transmission area and maximum pressure transmission of the specimens under an impact load were observed by using pressure-sensitive sheets. The modulus of elasticity and nanohardness of each denture base (n=10) were measured on 15×15×15×3mm3 specimen by using an ultramicroindentation system. The pressure transmission area, modulus of elasticity, and nanohardness data were statistically analyzed with 1-way ANOVA, followed by Tamhane or Tukey HSD post hoc test (α=.05). The maximum pressure transmission data were statistically analyzed with Kruskal-Wallis H test, followed by Mann-Whitney U test (α=.05). RESULTS Polymethyl methacrylate showed significantly larger pressure transmission area and higher maximum pressure transmission than the other groups (P<.001). Significant differences were found in modulus of elasticity and nanohardness among the four types of denture bases (P<.001). CONCLUSIONS Pressure transmission area and maximum pressure transmission varied among the thermoplastic resin denture base materials. Differences in the modulus of elasticity and nanohardness of each type of denture base were demonstrated.