It has been close to a century since calcium phosphate materials were first used as bone graft substitutes. Numerous studies conducted in the last two decades have produced a wealth of information on the chemistry, in vitro properties, and biological characteristics of granular calcium phosphates and calcium phosphate cement biomaterials. An in depth analysis of several key areas of calcium phosphate cement properties is presented with the aim of developing strategies that could lead to break-through improvements in the functional efficacies of these materials.

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Restorative materials in the new era should be “bio-active” and antibacterial effects are highlighted as one of the important properties. In order to achieve resin-based restoratives with antibacterial effects, an antibacterial monomer MDPB has been developed. The primer incorporating MDPB demonstrated cavity-disinfecting effects, and the world's first antibacterial adhesive system employing the MDPB-containing primer was successfully commercialized. MDPB is potentially applicable to various restoratives since immobilization of the antibacterial component by polymerization of MDPB enables no deterioration in mechanical properties of cured resins and exhibition of inhibitory effects against bacterial growth on their surfaces. For glass-ionomer cements used for atraumatic restorative treatment, the approach to provide antibacterial activity has been attempted by addition of chlorhexidine. Incorporation of 1% chlorhexidine diacetate was found to be optimal to give appropriate antibacterial and physical properties, being effective to reduce the bacteria in affected and infected dentin in vivo.

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Titanium and its alloys have good biocompatibility with body cells and tissues and are widely used for implant applications. However, clinical procedures place more stringent and tough requirements on the titanium surface necessitating artificial surface treatments. Among the many methods of titanium surface modification, electrochemical techniques are simple and cheap. Anodic oxidation is the anodic electrochemical technique while electrophoretic and cathodic depositions are the cathodic electrochemical techniques.
By anodic oxidation it is possible to obtain desired roughness, porosity and chemical composition of the oxide. Anodic oxidation at high voltages can improve the crystallinity of the oxide. The chief advantage of this technique is doping of the coating of the bath constituents and incorporation of these elements improves the properties of the oxide.
Electrophoretic deposition uses hydroxyapatite (HA) powders dispersed in a suitable solvent at a particular pH. Under these operating conditions these particles acquire positive charge and coatings are obtained on the cathodic titanium by applying an external electric field. These coatings require a post-sintering treatment to improve the coating properties. Cathodic deposition is another type of electrochemical method where HA is formed in situ from an electrolyte containing calcium and phosphate ions. It is also possible to alter structure and/or chemistry of the obtained deposit. Nano-grained HA has higher surface energy and greater biological activity and therefore emphasis is being laid to produce these coatings by cathodic deposition.

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In this article, we review the recent history of the development of dental CAD/CAM systems for the fabrication of crowns and fixed partial dentures (FPDs), based on our 20 years of experience in this field. The current status of commercial dental CAD/CAM systems developed around the world is evaluated, with particular focus on the field of ceramic crowns and FPDs. Finally, we discuss the future perspectives applicable to dental CAD/CAM. The use of dental CAD/CAM systems is promising not only in the field of crowns and FPDs but also in other fields of dentistry, even if the contribution is presently limited. CAD/CAM technology will contribute to patients' health and QOL in the aging society.

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This study was conducted to compare the shear bond strengths of different adhesive systems to White Mineral Trioxide Aggregate (WMTA). To this end, 40 cylindrical acrylic blocks with a hole in the middle measuring 4 mm diameter × 2 mm height were prepared. The hole was filled with WMTA, and the specimens were allocated into four groups: Group 1 – Prime & Bond NT; Group 2 – AdheSE; Group 3 – Xeno III; and Group 4 – Adper Prompt L-Pop. In each group, a different adhesive system and a compomer (Dyract AP) were applied over WMTA. Shear bond strengths were measured using a universal testing machine, and then the data were subjected to one-way ANOVA and Scheffé's post hoc test (p<0.05). Significantly lowest shear bond strength value was obtained with Adper Prompt L-Pop, whereas Prime & Bond NT revealed higher shear bond strength than the others (p<0.05). In conclusion, an etch-and-rinse adhesive system — which exhibited significantly higher shear bond strength than self-etch adhesive systems — could be a preferred choice when placing compomer materials upon WMTA.

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Chemical mechanical polishing (CMP) of cpTi (Ti) was carried out using two types of slurries, acidic and basic colloidal silica containing H₂O₂ up to 3 wt%, to obtain flat and mirror-polished surfaces without any contaminated and reacted layers. Polishing behavior and surface properties were investigated using AFM, EPMA, and XPS. Weight loss of Ti polished by CMP using the basic slurry was larger than that using the acidic one, and surface roughness was less than 2 nm RMS when basic slurry containing 3 wt% H₂O₂ was used. Moreover, three kinds of chemical species, OH^-, O^2-, and H₂O, were detected on the Ti surfaces polished by CMP using these slurries. Results of this study showed that CMP using colloidal silica containing H₂O₂ successfully created a mirror-polished surface without contaminated and reacted layers.

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To enable accurate implant placement and precise drilling following preoperative simulation, we developed the BoneNavi system. To realize more precise drilling when the holes are upsized, two methods of surgical guiding were attempted in the present study. One involved using multiple surgical guides with titanium tubes of different diameters, and the other involved using a single surgical guide but employing titanium drill guide tubes with different diameters. Drilling accuracy of the two newly developed methods was examined and compared with the results of drilling into a pig bone using only the initial surgical guide. Deviations of the position and angle with the two novel methods were similar: 0.17 mm and 1° respectively. As for the control group whereby drilling was done using only the initial surgical guide, the deviations were 0.25 mm and 3.50° — which were significantly larger than those achieved with the two novel methods. In light of the results obtained, our newly developed BoneNavi system is especially applicable for severe clinical cases that require precise implant placement.

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Carbon nanotubes (CNTs) are one of the most interesting nanomaterials because of their excellent characteristics. In this study, a transparent CNTs coating for cell culture dishes was developed and its properties for cell culture were estimated. Carboxylated multiwalled carbon nanotubes (MWCNTs) were dispersed in aqueous sodium cholate solution and applied on a collagen type I-coated cell culture dish (cover glass). The dish surface was homogeneously covered by MWCNTs without aggregation. The MWCNT-coated dish was slightly gray and had good transparency, so conventional optical microscopic observation of the cells on the MWCNT-coated dish was possible. Rat osteoblast-like cells cultured on the MWCNT-coated dish showed slightly lower viability and proliferation compared to the collagen-coated dish. The cell adhesion on the MWCNT-coated dish was much higher than that on the collagen-coated dish. Therefore, MWCNT-coating for dishes will be a useful new material for cell culture.

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The purpose of this study was to evaluate the shear bond strength, adhesive remnant index (ARI) and etching effect of two self-etching systems (Transbond Plus, Beauty Ortho Bond) at different application times (3, 10, 30 seconds) with and without agitation. Share bond strengths were examined and the ARI score was estimated (n=15). Enamel surfaces after priming were examined by SEM. Increasing application time and applying agitation of self-etching primers produced slightly increased etching efficacy. Increasing application time did not significantly increase the shear bond strength. Also, agitation did not significantly increase the shear bond strength except for specimen bonded with the Beauty Ortho Bond with 10 seconds application time. No significant difference was found in bond-failure sites among 10 groups. Although increasing application time and applying agitation of both self-etching primers did not affect the shear bond strength, increasing application time in indirect bonding technique should not cause remarkable adverse effect.

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The purpose of this study was to evaluate the effectiveness of several surface protectors for a glass-ionomer, a resin-modified glass-ionomer, and a polyacid-modified resin cement by determining dye uptake spectrophotometrically.
378 samples, made up of Ionofil U, Vitremer, and Dyract, were prepared and divided into groups of seven each. Positive and negative control specimens remained unprotected while the experimental specimens were protected with Finishing Gloss, Protect-It, LC Varnish, Adper Single Bond, or a nail varnish. The experimental groups and positive controls were immersed in 0.05% methylene blue solution, while the negative controls were immersed in deionized water. Results were evaluated using variance analysis.
Of the Ionofil U group, Adper Single Bond exhibited the least effective surface coating among the materials tested, while the best surface protection was obtained with LC Varnish in the Dyract group. However, no statistically significant differences were observed in the Vitremer group.

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This study was conducted to examine the ultrastructures of eight recently improved light-cure restorative composite resins with scanning and transmission electron microscopes (SEM and TEM). Additionally, Vickers hardness, volume/weight fraction of filler, and chemical composition were analyzed. Composite resins selected for evaluation were Beautifil II, Clearfil AP-X, Clearfil Majesty, Estelite Σ, Filtek Supreme, Filtek Z250, Solare, and Synergy. SEM and TEM images revealed a great diversity in ultrastructure, and Vickers hardness test showed significant differences amongst all the composite resins (except between Clearfil Majesty and Estelite Σ, and between Filtek Supreme and Filtek Z250). By means of EDX, similar elements such as C, O, and Si were detected, but the concentration was different in every composite resin. Results obtained in this study served to validate that the methods employed in this study — SEM and TEM at high magnification — were useful in examining the ultrastructures of composite resins. It was also found that the ultrastructure, size of filler particles, volume/weight fraction of filler, and chemical composition of the composite resins had an effect on Vickers hardness. Given the great diversity of ultrastructures amongst the composite resins, which stemmed from the different revolutionary technologies used to manufacture them, further studies are warranted in the search of clinical applications that optimally match the differing properties of these materials.

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To clarify the mechanism of methacrylate-induced toxicity, a total of 24 acrylates, methacrylates, and dimethacrylates were chosen for a structure-activity relationship (SAR) study in terms of NMR chemical shifts, semiempirical molecular descriptors, and reverse phase (RP)-HPLC log P. Molecular descriptors as well as bulk, electronic, and energy descriptors were calculated using the PM3/CONFLEX method. A significant multiple linear regression equation for methacrylates in mice was denoted as log 1/LD₅₀ (which was function [-(E_HOMO+E_LUMO)/2, log P]). Besides, significant linear regression equations for methacrylates were denoted as log 1/ED₅₀ in HeLa S3 and in HGF cells as function [E_HOMO and/or log P]. Results showed that the ¹³C NMR chemical shift of β-carbon for methacrylates was correlated with their E_HOMO. Findings of this study thus suggested that it might be possible to predict methacrylate-induced toxicity using physicochemical properties.

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The purpose of this study was to assess the effect of bending of dental gold alloy wires on the mechanical characteristics of wrought-wire clasps. We conducted a simulation of large deformation in straight wires by means of non-linear finite element (FE) analysis. A bending force increased the principal tensile stress on the outer surface of the bending corner and the compressive stress on the inner surface of the bending corner to their maximum values. After unloading with springback, a residual tensile stress was produced on the inner surface. A gold alloy wire clasp exhibited a relatively greater flexibility with small permanent deformation after the clasp tip deflection as compared to previously reported data for Co-Cr wires; this suggests that it is suitable for periodontally compromised teeth. Wire clasps are more susceptible to failure as compared to straight wrought wires because of the residual stress produced during the bending process.

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