The purpose of this study was to evaluate the remineralization effect of experimental fluoride varnish mixed with nano-tricalcium phosphate (TCP) and nano-hydroxyapatite (HA) on bovine teeth under demineralization and remineralization cycling by Vickers hardness. After fabrication of rosin-based experimental fluoride varnish with 5 wt% of NaF (EX) in the laboratory, 10 wt% of nano-hydroxyapatite (HA+EX) and nano-TCP (TC+EX) were mixed, respectively. Casein phosphopeptide-amorphous calcium phosphate (Tooth mousse) (CP) was used for comparison. Bovine incisors were impregnated by acrylic resin and exposed to caries inducing solution for 72 hours. EX, HA+EX, TC+EX, and CP were applied on the surface of bovine teeth. The specimens were immersed in a demineralization solution for 1 hour and in a re-mineralization solution for 23 hours and the cycle was repeated for 20 days. Vickers hardness was measured at baseline and after each treatment. CP group showed the highest hardness value at 24 hours after application of each material (p<0.05) and the other groups were not significantly different (p>0.05).On the 10th day of de-/re-mineralization cycling, the TC+EX group showed the highest hardness value (p<0.05), but not significantly different from the HA+EX group (p>0.05). On the 20th day, the TC+EX group kept the highest hardness value, followed by HA+EX and EX groups (p<0.05). In conclusion, experimental fluoride varnish with 10 wt% of nano-TCP showed higher remineralization effect on the enamel of bovine teeth during the de/re-mineralization cycling.

The purpose of this study was to evaluate the remineralization effect of experimental fluoride varnish mixed with nano-tricalcium phosphate (TCP) and nano-hydroxyapatite (HA) on bovine teeth under demineralization and remineralization cycling by Vickers hardness. After fabrication of rosin-based experimental fluoride varnish with 5 wt% of NaF (EX) in the laboratory, 10 wt% of nano-hydroxyapatite (HA+EX) and nano-TCP (TC+EX) were mixed, respectively. Casein phosphopeptide-amorphous calcium phosphate (Tooth mousse) (CP) was used for comparison. Bovine incisors were impregnated by acrylic resin and exposed to caries inducing solution for 72 hours. EX, HA+EX, TC+EX, and CP were applied on the surface of bovine teeth. The specimens were immersed in a demineralization solution for 1 hour and in a re-mineralization solution for 23 hours and the cycle was repeated for 20 days. Vickers hardness was measured at baseline and after each treatment. CP group showed the highest hardness value at 24 hours after application of each material (p<0.05) and the other groups were not significantly different (p>0.05).On the 10th day of de-/re-mineralization cycling, the TC+EX group showed the highest hardness value (p<0.05), but not significantly different from the HA+EX group (p>0.05). On the 20th day, the TC+EX group kept the highest hardness value, followed by HA+EX and EX groups (p<0.05). In conclusion, experimental fluoride varnish with 10 wt% of nano-TCP showed higher remineralization effect on the enamel of bovine teeth during the de/re-mineralization cycling.

The aim of this study was to evaluate the differences in setting times based on the methods for dental root canal sealers and calcium silicate cement used in root-end filling. Five kinds of dental root canal sealers and four kinds of calcium silicate cement for root-end filling were selected for the experiments. All materials were mixed according to the manufacturers’ instructions and stored at 37 ℃ with a relative humidity of 95%. Setting time was measured using a 1/4 pound Gillmore needle and a 1 pound Gillmore needle to determine the time until indentation was no longer visible or the time until 2 mm penetration was no longer possible. The determination of indentation was based on the absence of visible impressions on the material surface when Gillmore needle was placed vertically. When comparing indentation time and penetration time using same type of Gillmore needle, only ProRoot MTA using 1 pound Gillmore needle showed significant difference between measuring methods (P<0.05) while there are no differences in measuring methods in other materials (P>0.05). By this study, we could expect to measure a setting time relatively similar to real clinical conditions through indentation method.

The machining accuracy of zirconia prostheses fabricated by the subtractive (SM) and additive manufacturing (AM) was evaluated using the Merlon fracture test model in ISO 18675 (2022). The SM specimens were fabricated by a DWX-51D (Roland, Sydney, NSW, Australia) using two zirconia blocks (Katana Zirconia HT; KH, Katana Zirconia STML; KS). The AM specimens were prepared by a DLP type 3D printer INNI-Ⅱ (AON, Gunpo, Korea) using zirconia liquid slurry (INNI-CERA; PZ). The specimen STL image was acquired using a model scanner (E3, 3 Shape A/S, Copenhagen, Denmark). The machining accuracy of the specimens was analyzed by the RMS method superimposing the reference STL image and the specimen STL image in image analysis software (Geomagic Control X, 3D Systems, Rock Hill, SC, USA). From the results of the machining accuracy analysis, the KH and KS groups showed statistically significantly better machining accuracy (lower RMS) than the PZ group (P<0.05). The KH and KS groups showed higher machining accuracy as the thickness decreased, and the 0.2 mm and 0.3 mm experimental groups showed statistically significantly better machining accuracy than the 0.4 mm experimental group (P<0.05). On the other hand, the PZ group showed better machining accuracy as the thickness increased, with the 0.4 mm group showing statistically significantly better machining accuracy than the 0.2 mm and 0.3 mm groups (P<0.05). Within the limitation of this study, the thickness of the final zirconia prosthesis fabricated by additive manufacturing should be at least 0.4 mm for clinical use in dentistry.

PURPOSE: The aim of this study was to characterize the healing in the grafted calvarial defects of rats after adjunctive hyperbaric oxygen therapy. METHODS: Twenty-eight male Sprague-Dawley rats (body weight, 250–300 g) were randomly divided into two treatment groups: with hyperbaric oxygen therapy (HBO; n=14) and without HBO (NHBO; n=14). Each group was further subdivided according to the bone substitute applied: biphasic calcium phosphate (BCP; n=7) and surface-modified BCP (mBCP; n=7). The mBCP comprised BCP coated with Escherichia-coli-derived recombinant human bone morphogenetic protein-2 (ErhBMP-2) and epigallocatechin-3-gallate (EGCG). Two symmetrical circular defects (6-mm diameter) were created in the right and left parietal bones of each animal. One defect was assigned as a control defect and received no bone substitute, while the other defect was filled with either BCP or mBCP. The animals were allowed to heal for 4 weeks, during which those in the HBO group underwent 5 sessions of HBO. At 4 weeks, the animals were sacrificed, and the defects were harvested for histologic and histomorphometric analysis. RESULTS: Well-maintained space was found in the grafted groups. Woven bone connected to and away from the defect margin was formed. More angiogenesis was found with HBO and EGCG/BMP-2 (P<0.05). None of the defects achieved complete defect closure. Increased new bone formation with HBO or EGCG/BMP-2 was evident in histologic evaluation, but it did not reach statistical significance in histometric analysis. A synergic effect between HBO and EGCG/BMP-2 was not found. CONCLUSIONS: Within the limitations of this study, the present findings indicate that adjunctive HBO and EGCG/BMP-2 could be beneficial for new bone formation in rat calvarial defects.
Animals ; Bone Substitutes ; Calcium ; Humans ; Hyperbaric Oxygenation* ; Male ; Osteogenesis ; Parietal Bone ; Rats* ; Rats, Sprague-Dawley ; Transplants*

In this study, gold nanotubes were fabricated by electrophoretic deposition using a titania nanotube layer as a template, and then the surface characteristics, biocompatibility and antibacterial effect of gold nanotubes were evaluated. Gold nanotubes of 100 nm diameter were fabricated by depositing 4 nm and 15 nm gold nanoparticles on anodized 100 nm titania nanotubes by citrate reduction and electrophoretic deposition. As a result of the UV-Vis diffuse spectrophotometer, 4 nm and 15 nm gold nanotubes showed strong absorption at 702~774 nm and 753~760 nm, respectively. Also, the maximum absorption wavelength was shifted to the longer wavelength as the coating time of the gold nanoparticles increased. FE-SEM observation and EDX analysis resulted that 0.1~0.5 wt% gold nanoparticles uniformly were stacked on the top layer of titania nanotubes. As a result of MTT cell test, the relative absorbance value of all experimental groups after 24 hours and 48 hours of incubation exceeded 70% indicating excellent biocompatibility. The effect of the near infrared laser light on the adhesion and growth of gold nanotubes showed excellent antibacterial activity regardless of the coating time of gold nanoparticles. Therefore, it is confirmed that the gold nanotube coating technology based on the titania nanotube template is supposed to be highly applicable to a titanium implant surface treatment technology with the remote control thermal treatment of a near-infrared laser.
Absorption ; Citric Acid ; Nanoparticles ; Nanotubes ; Titanium

PURPOSE: The aim of this study was to evaluate the improvement of osteogenic potential of biphasic calcium phosphate (BCP) bone substitute coated with synthetic cell-binding peptide sequences in a standardized rabbit sinus model. METHODS: Standardized 6-mm diameter defects were created bilaterally on the maxillary sinus of ten male New Zealand white rabbits, receiving BCP bone substitute coated with synthetic cell binding peptide sequences on one side (experimental group) and BCP bone substitute without coating (control group) on the other side. Histologic and histomorphometric analysis of bone formation was carried out after a healing period of 4 or 8 weeks. RESULTS: Histological analysis revealed signs of new bone formation in both experimental groups (4- and 8-week healing groups) with a statistically significant increase in bone formation in the 4-week healing group compared to the control group. However, no statistically significant difference in bone formation was found between the 8-week healing group and the control group. CONCLUSIONS: This study found that BCP bone substitute coated with synthetic cell-binding peptide sequences enhanced osteoinductive potential in a standardized rabbit sinus model and its effectiveness was greater in the 4-week healing group than in the 8-week healing group.
Artificial Cells ; Bone Regeneration ; Bone Substitutes ; Calcium ; Durapatite ; Humans ; Hydroxyapatites ; Male ; Maxillary Sinus ; Oligopeptides ; Osteogenesis ; Rabbits

PURPOSE: The aim of this study was to determine whether biphasic calcium phosphate (BCP) bone substitute with two different concentrations of Escherichia coli-expressed recombinant human bone morphogenetic protein 2 (ErhBMP-2) enhances new bone formation in a standardized rabbit sinus model and to evaluate the concentration-dependent effect of ErhBMP-2. METHODS: Standardized, 6-mm diameter defects were made bilaterally on the maxillary sinus of 20 male New Zealand white rabbits. Following removal of the circular bony windows and reflection of the sinus membrane, BCP bone substitute without coating (control group) was applied into one defect and BCP bone substitute coated with ErhBMP-2 (experimental group) was applied into the other defect for each rabbit. The experimental group was divided into 2 subgroups according to the concentration of ErhBMP-2 (0.05 and 0.5 mg/mL). The animals were allowed to heal for either 4 or 8 weeks and sections of the augmented sinus and surrounding bone were analyzed by microcomputed tomography and histologically. RESULTS: Histologic analysis revealed signs of new bone formation in both the control and experimental groups with a statistically significant increase in bone formation in experimental group 1 (0.05 mg/mL ErhBMP-2 coating) after a 4-week healing period. However, no statistically significant difference was found between experimental group 1 and experimental group 2 (0.5 mg/mL ErhBMP-2 coating) in osteoinductive potential (P<0.05). CONCLUSIONS: ErhBMP-2 administered using a BCP matrix significantly enhanced osteoinductive potential in a standardized rabbit sinus model. A concentration-dependent response was not found in the present study.
Animals ; Bone Morphogenetic Protein 2 ; Bone Morphogenetic Proteins ; Bone Regeneration ; Bone Substitutes ; Calcium ; Durapatite ; Escherichia coli ; Humans ; Hydroxyapatites ; Male ; Maxillary Sinus ; Membranes ; Osteogenesis ; Rabbits ; X-Ray Microtomography

The purpose of this study was to evaluate the shear bond strengths between various hybrid computer-aided design (CAD)/computer-aided manufacturing (CAM) restorative materials and repairing resin. Two resin network-based hybrid (Lava Ultimate and Polyglass), one ceramic framework-based hybrid (Enamic), and one zirconia (Zenotec Zr bridge) CAD/CAM restorative materials were used in this study. The shear bond strength test and failure modes of four experimental groups designated LUS (Lava Ultimate), ENA (Enamic), PGB (Polyglass), and ZBR (zirconia control group) were characterized in this study. The hybrid CAD/CAM restorative materials showed stronger shear bond strengths in the sequence of PGB, LUS, and ENA (P < 0.05). The shear bond strengths of PGB and LUS groups showed significantly higher than those of ZBR (P < 0.05), while ENA did not show any significant difference from ZBR (P < 0.05). The PEG and LUS groups mostly exhibited cohesive failure, but the ENA and ZBR groups predominantly showed adhesive failure. Therefore, resin network-based hybrid CAD/CAM restorative materials such as Lava Ultimate and Polyglass should be more useful for intra-oral repairs.
Adhesives ; Ceramics ; Composite Resins ; Computer-Aided Design ; Prostaglandins B

The aim of this study was to investigate the antibacterial effect of fluoride varnish with antibacterial agents on Streptococcus mutans (S. mutans). Experimental fluoride varnish (EFV) with 5% NaF was fabricated. Five antibacterial agents were tested with 1 mM and 10 mM concentrations, respectively: Bakuchiol (BAK), Bavachalcone (BCC), Isobavachromene (IBC), and Bavachromene (BCM). MIC and MBC test was performed by antibacterial agents with and without EFV using 1.1 × 10¹⁰ CFU/ml of S. mutans. Cell viability test were performed using MTT test. Statistical analysis was done with ANOVA and Duncan's multiple range test at α=0.05. In the antibacterial agents without EFV, the MIC of BAK, BCC, and IBC was the lowest (0.015 mM), and the MBC of BAK was the lowest (0.031 mM). For the antibacterial agents with EFV, the MIC (0.031 mM) and MBC (0.062 mM) of BAK was the lowest, respectively. In MTT test, 1 mM BCM showed the highest cell viability (P < 0.05). This study suggest that BAK can be applied the fluoride varnish under the control of the concentration to develop antibacterial fluoride varnish.
Anti-Bacterial Agents ; Cell Survival ; Fluorides ; Microbial Sensitivity Tests ; Paint ; Streptococcus mutans