It has previously been demonstrated that apatite may be coated on the surface of titanium (Ti) at room temperature when the titanium is blasted with apatite powder. This method is known as the blast coating (BC) method. In this study, the osteoconductivity and tissue response to Ti implants blast-coated with apatite (BC implants) were evaluated using apatite-coated Ti implants produced using the flame spraying (FS) method (FS implants) and pure Ti implants as a control. Initial evaluation using simulated body fluid demonstrated higher osteoconductivity in BC implants than in FS implants. Therefore, specimens were implanted in rat tibias for 1, 3 and 6 weeks. At one week after implantation, BC implants showed much higher bone contact ratio when compared with FS implants; the bone contact ratio of BC implants was 75.7%, while the FS and pure Ti implants had ratios of 30.8% and 5.5%, respectively. The difference in bone contact ratio between BC and FS implants decreased with implantation time and the ratios were equal after 6 weeks. In conclusion, BC implants show higher osteoconductivity than FS implants, and thus BC implants are beneficial for early fixation of implants to bone tissue.

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This study aimed to assess dentin bond durability of 4-META/MMA-TBB resin cement over ten years, by evaluating the tensile bond strength, and SEM and TEM observations. Tensile bond strength of Super Bond C&B (SB) to bovine dentin was evaluated at 1 day and after 10 years. The mode of failure after debonding was observed by SEM. Interfacial ultrastructure and nanoleakage was observed by TEM at the baseline and after 10 y. The tensile bond strength significantly dropped after 10 y. The failure pattern shifted from cohesive failure in resin towards adhesive failure or cohesive failure in dentin. TEM observation revealed degradation of both resin and collagen networks within the hybrid layer and nanoleakage at the base of the hybrid layer after 10 y. The bond strength of SB to dentin significantly decreased, and the hybrid layer degraded, while the overlying hydrophobic resin layer showed little disintegration over 10 y.

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This study aimed to introduce a procedure for determining the bilinear elastic moduli (E1 and E2) of the periodontal ligament for a mathematical tooth model to analyse stress in the mandible. The bone and tooth morphology were scanned from a dry skull and an extracted intact tooth, respectively, and reconstructed in a three-dimensional finite element model. The model showed good agreement with previously reported in vivo premolar movement when an E1 for the first phase tooth movement of 0.05 MPa and an E2 for the second phase of 8.0 MPa with ε₁₂ of 0.075 were adopted. The mandible model analysis indicated that a remarkably high maximum compressive stress in the cervical cortical bone and the tensile stress in areas of masticatory muscle attachment were found. Future stress analyses using a jaw model may follow the process of determination of bilinear moduli to enhance accurate simulation with less calculation time.

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The purpose is to evaluate the effect of UV irradiation on the bond strength between epoxy-based glass fiber posts and resin cement. Twelve epoxy-based glass fiber posts were randomly divided into three groups. Group 1 (Cont.): No surface treatment. Group 2 (Low-UV): UV irradiation was conducted from a distance of 10 cm for 10 min. Group 3 (High-UV): UV irradiation was conducted from a distance of 1 cm for 3 min. A resin cement (CLEARFIL SA LUTING) was used for the post cementation to form resin slabs which contained fiber posts in the center. Microtensile bond strengths were tested and the mean bond strengths (MPa) were 18.81 for Cont. group, 23.65 for Low-UV group, 34.75 for High-UV group. UV irradiation had a significant effect on the bond strength (p<0.05). UV irradiation demonstrates its capability to improve the bond strength between epoxy-based glass fiber posts and resin cement.

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In this study, the wear resistance, hardness, elastic modulus, and the correlations between them of artificial denture teeth at the sub-enamel layer were examined. Four types of tested artificial denture teeth consisted of 3 conventional acrylic resin teeth (Cosmo HXL, Major Dent, and Yamahachi FX), 1 high cross-linked acrylic resin teeth (Trubyte Bioform IPN), 2 composite resin teeth (SR Orthosit PE, and Yamahachi PX), and 1 porcelain teeth (ACE Teeth). The two-body wear test was performed using a custom made pin on disc apparatus. Volume and weight loss were measured. Hardness and elastic modulus were also assessed by using a nanoindentation system. The results suggested wear resistance varied among the denture tooth materials. Wear resistance of high cross-linked acrylic resin teeth was the lowest. A definite relation between wear resistance and mechanical properties of materials could not be found in this study.

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This study investigated the effect of the combination of a dithiooctanoate monomer and an acidic adhesive monomer on adhesion to precious metals, precious and non-precious metal alloys. From a selection of four dithiooctanoate monomers and six acidic adhesive monomers, 14 experimental primers containing a combination of 5.0 wt% of a dithiooctanoate monomer and 1.0 wt% of an acidic adhesive monomer in acetone were prepared. Tensile bond strengths (TBSs) of MMA-PMMA/TBBO resin to nine kinds of precious metals, precious metal alloys, and non-precious metal alloys after 2,000 thermal cycles were measured. Results showed that there were no significant differences in TBS among the primers to all the precious and non-precious metal adherends tested (p>0.05). Highest TBS values (46.5–55.8 MPa) for bonding to Au alloy, Au-Ag-Pd alloy, Co-Cr alloy, and Ni-Cr alloy were achieved with the primer which contained 5.0 wt% 10-methacryloyloxydecyl 6,8-dithiooctanoate (10-MDDT) and 1.0 wt% 6-methacryloyloxyhexyl phosphonoacetate (6-MHPA). Therefore, 5.0 wt% 10-MDDT and 1.0 wt% 6-MHPA was determined as the optimal combination for bonding to precious metals, precious and non-precious metal alloys.

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This study investigated the bonding efficacy of a combined primer application which comprised a silane coupling agent, an acidic adhesive monomer, and a dithiooctanoate monomer, as well as the influence of shelf life on bonding. Five experimental primers (coded as Si-P-SS-1 to Si-P-SS-4, and Si-SS as the control) were prepared using 20.0–40.0 wt% 3-methacryloyloxypropyltriethoxysilane (3-MPTES), 0–7.44 wt% 6-methacryloyloxyhexyl phosphonoacetate (6-MHPA), and 0.50 wt% 10-methacryloyloxydecyl 6,8-dithiooctanoate (10-MDDT). After 24-hour storage at 23°C (Initial) and 2-month storage at 50°C (Aged), tensile bond strengths (TBSs) of a resin cement (ResiCem, Shofu Inc., Kyoto, Japan) to primer-treated porcelain, alumina, zirconia, and Au alloy were measured. With the Initial and Aged primers of Si-P-SS-1 to Si-P-SS-3, there were no statistically significant differences in the mean TBSs (MPa) [porcelain: 21.7–29.2; alumina: 21.4–25.3; zirconia: 20.3–24.5; and Au alloy: 23.4–27.6] among these three primers (p>0.05), but they were significantly higher than that of the control primer (p<0.05). The experimental primers Si-P-SS-1 to Si-P-SS-3 demonstrated good potential as multi-purpose primers: they had good shelf lives as single-bottle primer systems and were thus able to exhibit good bond strength to all the adherends tested after 2-month storage under accelerated aging conditions.

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This study evaluated apical periodontal healing after root-end sealing using 4-META/MMA-TBB resin (SB), and root-end filling using reinforced zinc oxide eugenol cement (EBA) or mineral trioxide aggregate (MTA) when root canal infection persisted. Apical periodontitis was induced in mandibular premolars of beagles by contaminating the root canals with dental plaque. After 1 month, in the SB group, SB was applied to the resected surface following apicoectomy. In the EBA and MTA groups, a root-end cavity was prepared and filled with EBA or MTA. In the control group, the root-end was not filled. Fourteen weeks after surgery, histological and radiographic analyses in a beagle model were performed. The bone defect area in the SB, EBA and MTA groups was significantly smaller than that in the control group. The result indicated that root-end sealing using SB and root-end filling using EBA or MTA are significantly better than control.

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A newly designed, light-curing adhesive was investigated for its bonding effectiveness to porcelain, alumina, zirconia, Au, Au alloy, Ag alloy, Au-Ag-Pd alloy, and Ni-Cr alloy. Four experimental adhesives were prepared using varying contents of the following: a silane coupling agent [3-methacryloyloxypropyltriethoxysilane (3-MPTES)], acidic adhesive monomers [6-methacryloyloxyhexyl phosphonoacetate(6-MHPA),6-methacryloyloxyhexyl3-phosphonopropionate(6-MHPP)and 4-methacryloyloxyethoxycarbonylphthalic acid (4-MET)], and dithiooctanoate monomers [6-methacryloyloxyhexyl 6,8-dithiooctanoate (6-MHDT) and 10-methacryloyloxydecyl 6,8-dithiooctanoate (10-MDDT)]. After all adherend surfaces were sandblasted and applied with an experimental adhesive, shear bond strengths (SBSs) of a light-curing resin composite (Beautifil II, Shofu Inc., Kyoto, Japan) to the adherend materials after 2,000 times of thermal cycling were measured. For the experimental adhesive which contained 3-MPTES (30.0 wt%), 6-MHPA (1.0 wt%), 6-MHPP (1.0 wt%), 4-MET (1.0 wt%), 6-MHDT (0.5 wt%) and 10-MDDT (0.5 wt%), it consistently yielded the highest SBS for all adherend surfaces in the range of 20.8 (4.8)–30.3 (7.9) MPa, with no significant differences among all the adherend materials (p>0.05). Therefore, the newly designed, multi-purpose, light-curing adhesive was able to deliver high SBS to all the adherend materials tested.

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The purpose of this study was to evaluate the effect of smear layer characteristics on the dentin bonding durability of HEMA-free and HEMA-containing one-step self-etch adhesives. Xeno V (XV; HEMA-free), G BOND PLUS (GB; HEMA-free) and Clearfil S³ Bond (S³; HEMA-containing), were applied to dentin surfaces prepared with either #180- or #600-grit SiC paper according to manufacturers’ instructions. Bond strengths to dentin were determined using μTBS test after 24-hour, 6-month, and 1-year water storage. In addition, nanoleakage evaluation was performed using an SEM. The smear layer characteristics affected water-tree nanoleakage formation in the adhesive layers of XV and GB, which contributed to a reduction in μTBS after 6-month water storage, while the characteristics did not affect the μTBS of S³. However, regardless of the smear layer characteristics, 1-year water storage significantly reduced the μTBS of all the adhesives and was associated with an increase in failures at the adhesive-composite interface.

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Recently, the use of all-ceramic restorations has increased and been applied for many types of clinical treatment such as bridges which can be made with high strength ceramic material: yttria partially stabilized zirconia (Y-PSZ) employing the CAD/CAM system. Consequently, points that can grind high strength ceramic material effectively are necessary for modifying the shape of restorations or removing them. So in our research, we fabricated new diamond points used to grind Y-PSZ. These points were made by electrodeposition of diamond grains. The diameter of the diamond grains are larger (200 μm) than that of traditional points (100 μm). High strength ceramic material was ground to assess the grinding weight and grinding depth various types of points. As a result, Y-PSZ could be ground efficiently with the diamond point which has a larger diameter and employs lager grains (200 μm).

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The purpose of this study was to evaluate gap formations under class V restoration using swept-source optical coherence tomography (SS-OCT). Wedge-shaped cavities were prepared on the buccal surface of 40 extracted premolar teeth at 2 locations; 1) cemento-enamel junction (CEJ) with enamel and cementum margin and 2) root surfaces with cementum margin. The cavity was treated with Clearfil S³ Bond, restored with Clearfil Majesty and polished with abrasive disks. The specimens were kept in water at 37°C for 24 hours and subjected to a thermocycling procedure. Gap formations at the tooth-restoration interface were measured with SS-OCT image and conventional dye leakage under a microscope. There was no effect of the locations of the cavity and the margins of the cavity on the gap formation. Therefore, a significant effect of the observational methods was observed. The gap formation was 0.89±0.48 mm with the SS-OCT, and the gap formation was 0.34±0.41 mm with the dye leakage. The observation with SS-OCT demonstrated a greater degree of gap formation than the observation with dye leakage.

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The purpose of this study was to determine if adhesion between various resin composites can occur by a chelation reaction of elemental ions. The surface composition of four commercially available resin composites (Beautifil II, Clearfil AP-X, Estelite Σ Quick and Solare) were measured by X-ray fluorescence analysis. Composite-to-composite adhesion with conventional silane coupling treatment was compared to self-etching primer treatment and evaluated by conventional shear bond strength testing. Our results detected Strontium and Barium (alkaline metallic earth ions) on the surface of Beautifil II and Clearfil AP-X resins. The shear bond strength values of self-etching primer treatments of Beautifil II and Clearfil AP-X was significantly higher than Estelite Σ Quick and Solare. Our data suggest that self-etching primer treatment is effective for adhesion of resin composites, depending on their filler composition, due to the chelation adhesion reaction between the acidic monomer and incorporated alkaline metal ions.

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The purpose of this study was to examine the microstructure of the adhesive interface between resin cement and dentin treated with a self-etching primer by SEM in order to clarify the adhesive efficiencies of four self-etch type resin cement systems, Bistite II (BII), Linkmax (LM), Panavia F2.0 (PF), and ResiCem (RC) to dentin. The fluidity and inorganic filler content of these cements were also determined to examine their influences on the adhesion. A hybrid layer with 0.5–1.5 μm thickness and many resin tags could be confirmed clearly at the interface between BII cement and dentin, but was not observed distinctly for the other resin cements. It was suggested that the hybrid layer and resin tags might contribute to the high adhesive efficiency for BII. As the fluidity of cement had been adjusted to be suitable for luting in all cements, it did not significantly influence the adhesive efficiency of cement.

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The purpose of our study was to re-evaluate the effects of surface treatment on the bond strength of repaired methacrylate-based dental composite materials including nanofillers (Ceram X, Dentsply). The microtensile bond strengths were measured before or after thermo-mechanical fatigue simulation. The treatments were as follows: (1)No treatment (negative control), (2)Bonding agent, (3) Acetone, (4)Acetone+Bonding agent, (5)Silane, (6)Silane+Bonding agent. In the digitized SEM image of the polished aged specimens without any surface treatment, the percentage of the visible fillers relative to the whole image was calculated. Before and after fatigue, no significant differences could be observed among the different pretreatment groups. Fatigue increased the microtensile strength values of Acetone and Silane groups. The digitized SEM image reveals that 11.5% of the exposed surface could be identified as uncovered filler surface. None of surface treatments (acetone, silane and bonding agent) contributed to increase the tensile strength of repaired composite samples including nanofillers.

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The aim was to characterize by atomic force microscopy (AFM) the nanostructure of human dentin surfaces affected by dental fluorosis (DF) before and after phosphoric acid etching. This study included 240 human dentin samples classified according to the severity of DF, which were divided into four groups using the Thylstrup-Fejerskov Index (TFI). Samples were analyzed by AFM before and after acid etching for 15, 30, and 60 s. The roughness (R_a) for healthy dentin, and dentin with mild, moderate, and severe fluorosis were 440 nm, 442 nm, 445 nm, and 449 nm, respectively. After 15, 30, and 60 s of acid etching, all healthy and fluorotic dentin samples increased in roughness (p<0.05). The diameter of dentinal tubule orifices (D_t) in healthy human dentin increased after acid etching for 60 s. We conclude that effective etching times are 15 s for healthy and mild dentin fluorosis, 30-s for moderately fluorosed dentin, and 45–60 s for severe fluorotic dentin.

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This study determined the fracture load of zirconia crowns veneered with four overpressed and four layered ceramics after chewing simulation. The veneered zirconia crowns were cemented and subjected to chewing cycling. Subsequently, the specimens were loaded at an angle of 45° in a Universal Testing Machine to determine the fracture load. One-way ANOVA, followed by a post-hoc Scheffé test, t-test and Weibull statistic were performed. Overpressed crowns showed significantly lower fracture load (543–577 N) compared to layered ones (805–1067 N). No statistical difference was found between the fracture loads within the overpressed group. Within the layered groups, LV (1067 N) presented significantly higher results compared to LC (805 N). The mean values of all other groups were not significantly different. Single zirconia crowns veneered with overpressed ceramics exhibited lower fracture load than those of the layered ones after chewing simulation.

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