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Among various dental materials and their successful applications, a dental implant is a good example of the integrated system of science and technology involved in multiple disciplines including surface chemistry and physics, biomechanics, from macro-scale to nano-scale manufacturing technologies and surface engineering. As many other dental materials and devices, there are crucial requirements taken upon on dental implants systems, since surface of dental implants is directly in contact with vital hard/soft tissue and is subjected to chemical as well as mechanical bio-environments. Such requirements should, at least, include biological compatibility, mechanical compatibility, and morphological compatibility to surrounding vital tissues. In this review, based on carefully selected about 500 published articles, these requirements plus MRI compatibility are firstly reviewed, followed by surface texturing methods in details. Normally dental implants are placed to lost tooth/teeth location(s) in adult patients whose skeleton and bony growth have already completed. However, there are some controversial issues for placing dental implants in growing patients. This point has been, in most of dental articles, overlooked. This review, therefore, throws a deliberate sight on this point. Concluding this review, we are proposing a novel implant system that integrates materials science and up-dated surface technology to improve dental implant systems exhibiting bio- and mechano-functionalities. [ABSTRACT FROM AUTHOR]

Abstract: Currently, dental bleaching and fluoride treatment agents are popular for esthetic purposes and prevention of plaque and caries formation. The corrosive effect of these agents on dental metallic materials has not been well documented. It was an objective of this in vitro study to evaluate and compare chemical and electrochemical corrosion behavior of seven metallic dental materials in commercially available fluoride and bleaching agents. Fluoride treatment agents were tested on Ti–6Al–4V and 17-4 stainless steel. Discoloration on these alloys was examined by a colorimeter and the naked eyes. Bleaching agents were tested on commercially pure titanium, Ni–Co–Mo alloy, type IV gold alloy, and amalgam. Electrochemical corrosion tests were also conducted for these materials, using each treatment agent as an electrolyte. All tested materials suffered from discoloration, which mostly disappeared after brushing. The fluoride-treated 17-4 stainless steel indicated severe intergranular attack, causing localized Cr depletion. The bleaching agents made the passivation layer on the metallic materials unstable. Within the limitations of this study, although these treatments are indicated for patients (enamel), it is proven that these agents are contraindicated for dental metallic materials. [Copyright &y& Elsevier]

Microbiology-related corrosion has been noted in industry for many years. It is widely recognized that microorganisms affect the corrosion of metal and alloys immersed in aqueous environments. Under similar conditions, the effect of bacteria in the oral environment on the corrosion of dental metallic materials remains unknown. The purpose of this study is to investigate the corrosion behavior of dental metallic materials in the presence of Streptococcus mutans and its growth byproducts. Samples were commercially pure titanium (CPT), Ti-6Al-4V (TAV), Ti-Ni (TN), Co-Cr-Mo alloy (CCM), 316L stainless steel (SSL), 17Cr-4Ni PH-type stainless steel (PH), and Ni-Cr alloy (NC). Using Gamry corrosion test system, surfaces were exposed to (1) sterilized Ringer's solution as a control for (2), (2) S. mutans mixed with sterilized Ringer's solution; (3) sterilized tryptic soy broth as a control for (4), and (4) byproducts of S. mutans mixed with sterilized tryptic soy broth. Corrosion parameters (E) OCP(, E)CORR(, I)CORR(, etc.) were corrected for all tested samples. Averaged values of these parameters were statistically analyzed) by t-test to identify significant differences. It was concluded that (1) S. mutans (reduced the E)OCP (of CPT, TAV, TN, and SSL,) and the byproducts of S. mutans (reduced the E)OCP (of TAV, TN, SSL, and PH. (2)(S. mutans)(increased the I)CORR (of PH, and)byproducts of S. mutans (increased the I)CORR (of all the samples. (3)(S. mutans)(reduced the E)CORR (of CPT, TAV and TN, and)the byproducts of S. mutans (reduced the E)CORR (of TN, SSL, PH, and NC. (4)(S. mutans)(increased the I)PASS (of CPT, and the)byproducts of S. mutans (increased the I)PASS (of CPT, PH, and NC.) [ABSTRACT FROM AUTHOR]

The cell attachment to bioapplicable titanium surfaces is an important parameter in the area of clinical implant dentistry and medicine. A major consideration in designing implants has been to produce surfaces that promote desirable responses in the cells and tissues contacting the implants. In this study, three titanium materials (commercially pure titanium – CPT –, Ti-6Al-4V, and TiNi) were treated mechanically, chemically, mechano-chemically, and thermally to produce concave surfaces with varying roughness. Using four media (distilled water, 1% NaCl aqueous solution, a suspension of human neutrophils, and a suspension of the MG-63 osteoblast-like cells), the initial contact angles were measured. Six readings (three drops each measured by two observers) were collected for each material and for each medium. The interclass correlation coefficients were used for the group comparisons. A one-way analysis of variance (ANOVA) and Tukey's HSD (honestly significant difference) statistical analyses were employed. It was found, for CPT, that (1) statistically, there were no significant differences among four media in contact angles, (2) the contact angle increased linearly with average roughness when the angles were higher than 45 degrees, and (3) the contact angle decreased linearly with roughness when the angle was less than 45 degrees. [ABSTRACT FROM AUTHOR]

Abstract: Electrical impedance spectroscopy (EIS) offers a quantitative method of measuring the stability of resin films in aqueous solution over time. Purpose: The purpose of this study was to measure the EIS of five experimental dental adhesive films (ca. 17μm thick) of increasing hydrophilicity (ranked by their Hoy''s solubility parameters), and how much these values change over 3 weeks in aqueous buffer. Methods: The resin films were placed in a U-shaped chamber and a pair of Ag–AgCl electrodes was used for EIS. The EIS results were confirmed by immersing the films in 50% AgNO3 for 24h to trace the distribution of any water absorption into the resins by TEM observations. Results: The resistance (R r) of the resins 1–4 films increased most during the first day, and varied from 1×1011 ohm for resin 1, to 40Ω for resin 5 at day 1. The day 1 R r values of resins 1–4 were inversely proportional to their Hoy''s solubility parameter for hydrogen bonding forces. Electrical impedance values of resins 1–3 and 5 varied widely but were relatively constant over time, while those of resin 4 decreased more than 99% from day 1 to 21 (). Capacitance (C r) of films of resins 1–4 all increased over the first day and then were relatively unchanged over the 20 days (except for resin 4 that continued to increase) and were between 0.01 and 1nF. Silver uptake by TEM revealed the development of water-filled branching structures that formed in resins 4 and 5 over time. [Copyright &y& Elsevier]

Summary: Objective: This study investigated the effects of H2O2-treatment of titanium surfaces on cement shear bond strengths, and characterized H2O2-treated titanium surfaces. Methods: Using 34.5% hydrogen peroxide solution, cp Ti plates (10mm×10mm×1mm) were treated by (1) an immersion method, and (2) halogen irradiation while immersed in H2O2 for varying times. A cylindrical block (6mm diameter, 4mm height) of four different cements was bonded onto H2O2-treated surfaces. The cement bond strengths were evaluated under shear mode. Treated surfaces were also characterized for color change, wettability, AC impedance, and transmission electron diffraction of stripped oxide film. Results: The cement shear bond strength of cp Ti treated with H2O2 and halogen for 160s was the highest and was approximately 14 times higher than the un-treated control cp Ti plates. Bond strengths are correlated linearly to wettability. The more surface wetted with the cement material, the higher the resultant shear bond strength value. Significance: These results suggest that a combined treatment of hydrogen peroxide and halogen light irradiation provides an effective surface condition with appropriate oxide film thickness to enhance the cement bond strength. [Copyright &y& Elsevier]

The success of the oral rehabilitation of implant patients depends not only on the osseointegration of implant fixtures but also on maintaining the integrity of the connection of prosthetic superstructures to these fixtures. It was an objective of the present study to evaluate and compare cement bond strengths among rolled (R), cast (C) and metal-injection-molded (M) commercially pure titanium plates which were bonded with Panavia 21 (Kuraray) and Imperva (Shofu) cements. Two plates (15 × 5 × 1 mm) of each R, C, and M were lap-jointed (lap length: 5 mm). The joints were stored in 37°C distilled water for 24 h, followed by tensile tests with an INSTRON system under 1 mm/min crosshead speed. It was found that the bond strength of R with Panavia 21 (PAN) was 5.31 (SD : 1.5) MPa and 2.30 (0.83) MPa with Imperva (IMP) cement. These were improved by applying an alloy primer to 7.08 (1.31) MPa and 6.72 (1.63) MPa, respectively. Using PAN with primer application, C and M samples showed bond strengths of 7.99 (1.31) and 7.20 (2.50) MPa, while they were 5.83 (2.15) and 6.79 (2.09) MPa using IMP with primer. There was a significant difference (ρ < 0.01) between PAN and IMP cements for C samples. Additionally, samples were pre-oxidized at 100°C in air for 10 min. Bond strengths of PAN with the primer were 5.69 (2.25), 9.14 (1.28), and 5.60 (3.13) MPa for R, C, and M sample groups. If the cement with the primer was applied immediately after the polishing (instead of pre-oxidized surfaces), bond strengths were improved to 9.14 (1.78) for R, 9.29 (1.85) for C, and 9.36 (1.81) MPa for M sample group. At ρ < 0.05 level, there was a significant difference between surface pre-condition of R and M, but no significance with C. [ABSTRACT FROM AUTHOR]