This study evaluated the physical and bonding properties of new surface-coating resins incorporating an antibacterial monomer MDPB (1, 5, 10 or 15 %) to be used for prevention of root surface caries. Although hardness was reduced by the addition of MDPB, abrasive wear of the experimental resins by toothbrushing was considered minimal. The incorporation of MDPB did not adversely affect the bonding ability to cervical dentin. These results suggest that the MDPB-containing coating resins tested are promising for protecting exposed root surfaces from caries for long period.

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Aesthetic restorations have a great demand as a treatment of dentin exposure in fluorosed teeth. This laboratory study shows the bonding efficacy of Clearfil SE Bond, Clearfil Tri-S Bond and Single Bond to fluorosed dentin. Human molars were categorized with Thylstrup-fejerskov Index and bonding dentin interfaces were created for microtensile bond testing, field emission scanning electron microscopic morphological analysis. Clearfil SE Bond showed the best bonding performance to fluorosed dentin out of the three bonding materials. Different dentin bonding interface and surface morphologies were observed with each bonding system.

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In last decade, the two-step self-etching adhesive technology led to the development of all-in-one systems. All-in-one systems are undoubtedly the most user-friendly adhesives, but have been associated with lower effectiveness as compared to two-step self-etching adhesives. It has been reported that the double-application of some all-in-one bonding systems were successful to increase the bond strength to sound dentin. The purpose of this study was to examine the adhesion of two type experimental self-etching adhesives to enamel and dentin and to evaluate the effect of double-application of three all-in-one adhesives on bond strength.

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Introduction: Cervical sealing should be an important factor for good outcomes of Class II resin restoration. At cervical areas, dentinal tubules run horizontally, meaning that open dentinal tubules may easily remain and cause leakages, and, in addition, margins may locate on cementum. Thus, tight sealing is sometimes not so easy at cervical margin areas. Because shrinkage of cured composite resin (CR) is the main cause of microleakages, the thin layer of resin cement for resin inlay may cause less microleakage. It is shown that saliva disturbs the adhesion of resin. The aim of this study was to evaluate the cervical margin microleakage of resin cement layers of class II CR inlay restorations with and without saliva contamination. Materials and Methods: Crown portions of 20 extracted teeth were cut off at near enamel-cementum junction to simulate cervical margins of Class II. Panavia F2.0 and Linkmax resin cements were used to cement with Clearfil AP-X CR resin bodies according to the manufacturer's recommendations with and without saliva contamination (a total of four groups: n=5 each), after the cut surfaces were irrigated with 12% EDTA pH 7.0. After dipped in 0.5 mg/ml safranin-O/ propylene glycol for 24 hours at 37degree Celcius, the sample teeth were cut into two pieces in mesio-distal plan, and dye penetration was evaluated using a stereomicroscope (Nikon, Japan). Results and Discussion: No cases using Panavia and Linkmax were observed to have dye penetration unless saliva contaminated. However, saliva affected the tight sealing, because 3 teeth out 5 had leakages when intentional saliva contamination was given at the time adhesion, indicating resin inlays with resin cement would give good sealing even at the cervical margins. More considerations may be needed for actual practice under clinical conditions. Conclusions: Tight sealing, even at cervical margin areas of class II restoration using resin inlay cemented by resin cement, could be obtained.

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Introduction: Calcium phosphate cements (CPC) are used as in surgery or dentistry for bone filling materials. In this study, brushite cement was selected because they are resorbable in physiological conditions. Although brushite cement which was one of CPC is viewed as a promising bone substitute material, their setting time and mechanical resistance is too fast and weak to allow their application. It has been demonstrated that mechanical properties of CPC can be modulated through variation in powder composition, liquid phase, liquid-to-powder (L/P) ratio, ageing condition, and many organic or polymeric additives. More recently, a series of studies showed that the incorporation of water-soluble fiber into CPC substantially increased strength and fracture resistance. Therefore, the aim of this study was investigated the effect of addition of dextrin dispersion on the physical and mechanical properties of brushite cement as a function of L/P ratios. Materials and Methods: Brushite cement was formulated with an equimolar powder mixture of b-tricalcium phosphate (b-TCP) and monocalcium phosphate monohydrate (MCPM) and liquid phase with 0.5M citric acid (CA). Brushite-dextrin composite cements were prepared with 40wt% dextrin dispersion in 0.5M CA aqueous solution. The composite cements were prepared by as a function of three different L/P ratios (0.4, 0.45, and 0.5). The initial and final setting times of cements were determined using the Gilmore needle technique (1/4 lb and 1 lb). Samples for compression testing were prepared by placing manipulated cement slurry into a PTFE mold of diameter 6mm and height 12 mm. Once set, dry compressive strength of samples was measured after the set at room temperature in the air for 24h. On the other hand, wet compressive strength samples were measured after the storage at 37 C and 100% relative humidity in water bath for a period of 24 h. Compressive strength was tested by UTM. Results and Discussion: The setting time of brushite cement without dextrin was about 10min at 0.3 of L/P ratio. The setting time of brushite-dextrin composite cement was increased from 7 to 12min when three different L/P ratios (0.4, 0.45, and 0.5). The L/P ratio of 0.45 was chosen for comparison of mechanical properties in this study. Dry and wet compressive strengths of brushite-dextrin composite cements (13 MPa and 4 MPa) were higher than those of brushite cement without dextrin (7 MPa and 1 MPa). Also, the work-of-fracture of composite cement (208 J and 20 J) was more significantly improved than that of brushite cement without dextrin(106 J and 6 J). Conclusions: Although L/P ratio was increased, the mechanical strength of brushite-dextrin composite cement was more improved than brushite cement without dextrin in both dry and wet condition. This study demonstrated that brushite-dextrin composite cement had acceptable mechanical strengths for clinical applications under an appropriate setting time.

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Introduction: Dental lasers for cavity preparation have been in existence since the 1960s. The erbium laser such as Er:YAG and Er,Cr:YSGG are commonly used for cavity preparation as alternative methods instead of using the high speed hand piece. Many investigations have focused on the bond strength of composite resin and adhesive systems to dentin prepared by these laser systems. There are a few reports about the bond strength of glass ionomer cement to laser prepared dentin. The purpose of this study is to determine the microtensile bond strength of three different types of glass ionomer cements to Er,Cr:YSGG laser prepared dentin.

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Fatigue tests and delayed fracture tests under sustained tensile loading of titanium were carried out. From these results, it was concluded that stress-corrosion cracking related with hydrogen was suspected for delayed fracture of small titanium devices in vivo.

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Comparison of Shear Strength, Fatigue-Limit, and Fatigue-Life in Metal/Enamel Bonds. *PADIPATVUTHIKUL P, MAIR LH. (University of Liverpool, School of Dental Studies, UK) Objectives: To compare the Shear Bond Srength (SBS) of resin-bonded metal/enamel bonds with the Fatigue-Limit and Fatigue-Life of identical joints. Materials and Methods: 285 discs of Ni/Cr-alloy(dia 5mm*4mm) were cast and treated by either (1)Sandblasting with aluminium oxide or (2)Sandblast + 15 min electrolytic-etch in HCl. The discs were bonded to etched enamel (37% HPO4/30 sec) using 3 bonding systems. Ten discs of each group were subjected to Shear test in a Universal Testing Machine5 (CHS= 50mm/min). Fifteen discs of each group were subjected to a Staircase Fatigue-Test using 5000 cycles, load increment = 4 kg. Another 10 discs were subjected to cyclic loads of 20, 10, and 5 kg to determine Fatigue-Life of the bonds. Load data was compared by correlation analysis and cycle data by Weibull statistic to determine the beta and alpha coefficients for the 3 loads. Results and Conclusions: The Fatigue-Limit of the bonds was much lower than the Shear strength and there was no correlation between the two values. Fatigue-Limit was not a good predictor of the Fatigue-Life in this study.

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The effects of oxide-forming elements, In, Fe, Sn, Zn, on color variations of the oxidized Pd-free Au-Pt-based high noble dental alloys for porcelain veneering were investigated by means of spectrophotometric colorimetry and thin-film X-ray diffraction technique. Activity of high temperature oxidation was strongly dependent on the base metal elements included. The most active oxide-forming element was Zn, followed by Sn, In, and Fe. From the viewpoint of color stability of the oxidized Au-Pt-based high noble dental alloys for porcelain veneering, the inclusion of a small amount of In was found to be advantageous.

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BMP is a well known cytokine which induces new bone in vivo. Many kinds of sccafold were tried for the combination with BMP, and nature derived polymers showed execellet enhancement of BMP activity. In order to control the shape of induced new bone, several polymers were used as scaffolds in this experiment. Experimental specimen showed new bone formation in vivo, and the possibility for the clinical usage was suggested.

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The objective of this study was to evaluate the electrochemical behavior of titanium in basic saline solution containing hydrogen peroxide. The electrochemical behavior of CP-Ti in basic saline solution containing hydrogen peroxide indicated a lower open circuit potential and higher passive current density than that in solution without hydrogen peroxide. In conclusion, the basic saline solution containing hydrogen peroxide corroded CP-Ti.

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This study compared differences in discoloration caused by hydrogen peroxide-containing solutions at various pHs in several titanium-based alloys. At pH4, all titanium-based alloys showed remarkable discoloration, and the ΔE*ab value was more than 18. ΔE*ab values at pH 5 and 6 for TI and all the titanium-based alloys except TNI were lower than those at pH 4. Discoloration of titanium-based alloys in acidic hydrogen peroxide-containing solutions may be caused by peroxide-induced oxidation.

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The aim of this study was to characterize the electrochemical behavior and biocompatibility of pure titanium and a series of experimental Ti-(10-40) wt% Zr alloys.Except Ti-5Cr and Ti-10Cr alloys, the bond strengths of all the other Ti-Cr alloys exceeded the lower limit value in the DIN 13.927 standard for the 3-point bending test (25 MPa). In the Ti-Cr alloys, bond strength tended to increase as the Cr component increased.Under SEM observation, c.p. Ti surface exhibited the least amount of retained porcelain on the metal surface after debonding, and mainly adhesive bond failure. However, more traces of retained porcelain were observed on specimens that contained higher alloying elements, such as Ti-25Cr and Ti-30Cr alloys, attesting to a better mechanical performance.

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The improvement of zirconia have brought the potential to metal free restoration in dental prosthesis. Tetragonal zirconia polycrystals (TZP) was known as high strength and toughened material. This study was intended to evaluate the biaxial and three-point flexure strength of two zirconias and an alumina.

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Introduction: The porcelain in the PFM systems is the type of porcelain which is widely used in dentistry. For this reason, efforts have been made in this project to make dental porcelain powder of a metal bonding type. Material and Method: In order to do so, Vita opaque porcelain powder (Vmk 68 N) with ISO 1995 specifications was used to produce the new powder. First, the Vita opaque porcelain powder was tested and analyzed by using a scanning electron microscope (SEM) and through X-ray diffraction (XRD) and X-ray fluorescence (XRF) analysis. After the Vita powder compound had been obtained and after it had been compared with the existing information and tables, a similar powder was made by using domestically-produced raw materials. After different formulas had been prepared in the course of several stages and after the porcelain powder had been made on the basis of the formulas, a sample of each porcelain powder produced underwent various tests following the melting, fritting, grinding, sifting, heating and granulating stages. Results and discussion: the characteristics of the opaque porcelain powder produced (T1/14) were similar to those of Vita opaque porcelain powder, and its bending strength, opacity, baking temperature, glazing, contraction degree and adhesion to metal were confirmed through different tests. Conclusion: According to this study, body porcelain was used for PFM system contains different components for creates satiable chrematistics. This material divided in these category. Opacifier, Glass modifier, Color modifier, Thermal Expansion adapter. In this research discussed about each type of these materials and Have close Examination on advantage and disadvantage of them.

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Introduction: Our previous study showed that hydroxyapatite (HAp) synthesized in the presence of aspartic acid (Asp) changed the morphology and crystallinity of synthesized HAp. FTIR results indicated that Asp was included in the synthesized HAp. However, the mechanism how Asp is uptaken in the HAp is not fully understood. To understand this mechanism, the adsorption/desorption of Asp onto/from HAp particles was examined. Materials and Methods: For the adsorption study, 200 mg of HAp powder was mixed with 40 ml of PBS containing Asp (0.05-0.25 mol/l) by stirring for 2 h at a controlled pH 7.4 at 80⁰C. For the desorption study, 10 mg of HAp powder synthesized in the presence of Asp (HAp-Asp, 0.05-0.5 mol/l) was mixed with 10 ml of PBS or 5-20 mmol/l NaCl dissolved PBS by 1 h stirring. In both the adsorption and the desorption study, Asp in the supernatant liquid was collected and measured by UV-VIS spectrophotometer. FTIR analysis of precipitated particles was also performed to confirm the adsorption/desorption of Asp onto/from HAp. Results and Discussion: Adsorption study showed that adsorbed amount of Asp onto normal HAp increased linearly with increase of Asp concentration (0.05-0.25 mol/l) in the solution. FTIR data of precipitated particles confirmed the adsorption of Asp onto normal HAp. To understand whether Asp in HAp-Asp is either a simple adsorption or not, we evaluated the desorption of Asp from HAp-Asp. If it is a simple Asp adsorption onto HAp, Asp release from HAp-Asp would be possible by altering the ionic strength of solutions. However, different ionic strength (NaCl, 5-20 mmol/l) dissolved in PBS did not enhance the desorption of Asp from HAp-Asp (0.05-0.5 mol/l). Therefore, it might be considered that Asp in HAp-Asp is physically packed in the apatite structure so that it cannot be released from HAp-Asp.

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To develop a new biodegradable scaffold biomaterial reinforced with a frame, CO₃Ap, which has crystallinity and a chemical composition similar to bone, was synthesized at pH 7.4 and 60 C. Then, the CO₃Ap was mixed with a neutralized collagen gel and the CO₃Ap-collagen mixtures were lyophilized into sponges in a HAp frame ring with 0.5 mm pores. Mouse osteoblast MC3T3-E1 cells were cultured on the CO₃Ap-collagen sponge. Furthermore, these sponge-frame complexes were implanted beneath the periosteum cranii of rats. A sectional view of hematoxylin-eosin staining confirmed that osteoblast cells had well invaded the CO₃Ap-collagen sponge. At the animal experiment, newly created bone was observed toward the inner core of the complex from the surface of the rat periosteum cranii after 8 wks. When these sponge-frame complexes with rh-BMP2 were implanted beneath the periosteum cranii of rats, sufficient new bone was created after 4 wks implantation.

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In this study, the viability of Streptococcus mutans planktonic and biofilm cells after exposure to antibacterial monomer MDPB for a short period was assessed. The results indicate that unpolymerized MDPB at 1000 µg/mL (8 times the MBC) was effective to kill S. mutans in suspension and biofilm within 60 sec, suggesting its effectiveness for cavity disinfection under clinical situation.

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In recent experiments, we have tried to induce the formation of bone from immature muscular tissue in vitro using BMP as a source of cytokine, and e-PTFE as a scaffold. To promote differentiation to the bone-like tissue, the influence of the Ca²⁺ was examined in this experiment. It was found that the addition of the Ca standard solution to the medium is very effective for this model of tissue engineering.

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The aim of this study was to evaluate the effect of treating Ti with phosphorylated pullulan or photo-reactive gelatin on the cell attachment and proliferation. Adsorption of phosphorylated pullulan significantly accelerated cell proliferation. It was found that the growth of cells on titanium could be regulated by pattern-immobilized gelatin. These facts indicate that these materials can be used to fabricate bioactive Ti implants.

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Previous studies showed that octacalcium phosphate (OCP) combined with collagen (OCP/Col) enhances bone regeneration in bone defect. In the present study, OCP/Col disc (1 mm or 3 mm in thickness) were implanted into the periosteal region in rat crania to investigate the bone regenerative properties of OCP/Col. The maximum thickness of the bone with implant was measured parallel to the calvaria. The histological sections were cut and activities of tartrate resistant acid phosphatase (TRAP) were stained to examine phagocytotic multinucleated giant cells. The effect of implantation on crystalline phase of OCP in the implant was examined by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The present study suggests that new bone formation on OCP/Col and biodegradation of OCP/Col are depending on the thickness of OCP/Col.

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The authors have demonstrated that wire-type electric discharge machining (W-EDM) of titanium (W) allowed a microstructured surface with an irregular morphology as well as thicker oxide layer. Additionaly, those surface characteristics have favorable scaffold prperties for osteoblastic cells. (2005, IADR, Boltimore). Thus, this study aimed to investigate the bone regenerative potential of rat mesenchymal stem cell (RMSC) cultured on W-EDM.

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It was examined the inherent changes in mouse osteoblastic cells (MC3T3-E1 cell) placed on two different sintered surfaces: rutile and anatase TiO2, by ALP staining. Anatase TiO2 materials, when heated to high sintering temperatures, become rutile. Anatase TiO2 specimens sintered at low temperatures, anatase crystal phase remained, did not under do this change and resulted in a negative ALP staining, high temperatures, which turned to rutile phase, change resulted in a positive ALP staining.

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Few data exist with respect to the clinical performance of all-in-one adhesive systems., The aim of this study was to evaluate the retention and marginal staining of resin composite restorations bonded with Clearfil S3 Bond or G-Bond all-in-one systems placed in noncarious cervical lesions. Sixty restorations were placed in 11 subjects, mean age 62.5 years. Restorations were bonded and placed according to the manufacturers? instructions. No enamel etching was performed on the enamel margins prior to restoration placement. Patients were recalled at 6 months, and 1year, with all restorations being able to be evaluated for presence and marginal staining. All restorations were present. Slight marginal staining was observed on 4 restorations for S3 and 3 restorations for G-Bond. The early results of this clinical evaluation are showing good outcomes at this stage for both materials

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INTRODUCTION: Oral candidiosis is the most common fungal infection encountered in dentistry. PURPOSE: The purpose of this study was to investigate quantitively adhesion of Candida albicans to different maxillofacial silicone materials in RPMI 1640. The quantitively measurement was provided by use of a colorimetric method (XTT). RESULT: There was adhesion on the maxillofacial silicone materials. However there was no measured differences among materials. (p>0.01). CONCLUSION: This finding emphasizes that C. albicans adhere to maxillofacial silicone materials Key Words: C. albicans, Adhesion.

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