The purpose of this study was to evaluate effects of fabrication of thermoplastic appliance on the dimensional stability of 3D printed dental models. A digital reference model was printed by different printing materials and densities [acrylonitrile butadiene styrene (ABS) and polylactic acid (PLA); 20, 40 and 60%]. Thermoplastic appliances were then fabricated with printed models for three times and models were scanned at three different stated; following the print out, following the fabrication for one time and three times. Tooth and arch measurements were performed to evaluate the accuracy and dimensional stability of printed models after fabrication of thermoplastic appliances. Printed models were not significantly different from the digital reference model regardless of different materials and densities. After the first fabrication of the appliance, most of measurements were decreased in PLA models ranged from 0.05 to 0.24 mm (p<0.05), whereas only a few measurements were decreased in ABS models (p<0.05). After fabrication for three times, measurements were more decreased in PLA models ranged from 0.04 to 0.42 mm (p<0.05) and some measurements were decreased in ABS models ranged from 0.08 to 0.27 mm (p<0.05). ABS models showed relatively good dimensional stability, but the PLA models showed significant dimensional changes even after initial fabrication of the appliance. Repeated fabrication of the appliances increased dimensional changes in printed models, especially printed with PLA.

The purpose of this study was to fabricate platinum (Pt), one of the plasmonic nanoparticles that induces localized surface plasmon resonance (LSPR) effects caused by the pairing of plasmon with the electric field of visible-near infrared light, coated 100 nm titania (Pt-TiO2) nanotubes to evaluate the surface properties and laser mediated antibacterial effects. From the analysis of UV-VIS-NIR spectrum, the light absorptions of Pt-TiO2 nanotubes were detected at wavelengths 399–429 nm, 527–579 nm, and 806–906 nm, respectively, and one of the detected wavelengths was suitable for the laser used in this study (OCLA, Wavelength: 405). From the observation of FE-SEM, as the platinum coating time increased, the inner diameter of the Pt-TiO2 nanotubes decreased from 68.8 nm to 48.8 nm, and the shape of the platinum nanoparticles coated on the top layer of the titania nanotubes changed from spherical to rod. From the results of contact angle measurement, the contact angle of water increased from 11.94°to 19.84°as the platinum coating time increased from 1 minute to 3 minutes. The Staphylococcus aureus antibacterial test resulted that 98% or more bacterial reduction of all Pt-TiO2 nanotube groups were observed after laser irradiation (P<0.05). Live-dead assay and MTT assay indicated that laser irradiation did not affect cell death. Therefore, Pt–TiO2 nanotube exhibiting a local surface plasmon resonance effect is expected to have many potentials for semi-permanent antimicrobial implant surface treatment without antibacterial drugs.

In this study, clinically applicable methods of improving the bond strength between Y-TZP and the bracket were considered, which the method was confirmed for the durability in a humid oral environment. The bond strength of Y-TZP bonding surface and the surface characteristics were analyzed following the surface treatment of Y-TZP specimens with conditioning by 30 μm tribochemical silica coating, or tribochemical silica coating with one of the following primers: silane, MDP, or an MDP-containing silane primer. It was found that after surface treatment, the surface roughness of all groups increased (p<0.05), and Si was uniformly distributed on the Y-TZP surface after silica coating. The bond strength value of the group treated with silane primer and tribochemical coating was not significantly different after thermocycling (p>0.05). The group treated with MDP primer and tribochemical silica coating showed a significant difference in bond strength values after thermocycling (p<0.05), and it showed the lowest bond strength values except the untreated groups (p<0.05). The group treated with tribochemical silica coating and MDP-containing silane primer showed the highest bond strength values (p<0.05), and was not significantly different after thermocycling (p>0.05). Therefore, the surface treatments of Y-TZP with MDP-containing silane primer after 30 μm tribochemical silica coating enhanced the bond strength to the orthodontic metal bracket; such a clinically applicable method may advance studies on the surface treatment of Y-TZP.

The objective of this work was to verify the antimicrobial effect and the characteristics of the tissue conditioner containing silver-chitosan nanocomplex at in vitro level. Nanocomplex was synthesized by the chemical reduction of silver nitrate and chitosan in aqueous solution with sodium borohydride as a reducing agent. Silver-chitosan nanocomplex was incorporated to tissue conditioner as powder to powder ratio with different weight percentage (%) of 0 (control), 1.0, 3.0, 5.0 and 7.0. The antimicrobial effect was assessed by colony forming unit in retrieved two streptococcal suspensions inoculated on specimens and cytotoxicity was measured using human gingival fibroblasts by MTS assay. Surface topography, Ag ion release and ultimate tensile strength tests were conducted for mechanical validity. The significantly reduced bacterial adhesions were observed above 5.0% loading while all of tested samples did not show cytotoxicity when compared to the control. Ag ion releases were detected with the dose-dependent of initial silver loadings with gradual decreasing over time. Modified tissue conditioner revealed similar microscopic surface textures and expressed no significant tensile strength changes (P>0.01) as compared to unmodified. Within some limitations in present study, the tissue conditioner loaded by 5.0% of silver-chitosan nanocomplex can be candidate as a novel denture biomaterial without mechanical hazards. For a clinical specification, future studies including in vivo, multi-strain or factor assays, and additional physical tests were still required.

This study aimed to assess the sustainability of antibacterial agents mixed with experimental fluoride varnish (EFV) against S. mutans. Five antibacterial agents [Xanthorrhizol (XAN), Bakuchiol (BAK), Bavachalcone (BCC), Isobavachromene (IBC), and Bavachromene (BCM)] were used and incorporated into the EFV to make the final concentration of 10 mM. Then, 5 μL of antibacterial agents mixed with EFV were applied on polyethylene terephthalate film disc (5 mm diameter). The positive and vehicle control were ampicillin and DMSO mixed with EFV, respectively. Each group was stored in distilled water in a 37℃ shaking water bath at 80 rpm for 0 hour, 4 hours, 1 day, 2 days, 3 days, 5 days, 10 days, 20 days and 30 days. The sustainability of the antibacterial activities was evaluated with the inhibition zone by the agar diffusion test. The antibacterial activities of all antibacterial agents were sustained for 30 days. Among them, BCC showed relatively higher antibacterial activities up to 30 days compared to other groups. This study suggests that antibacterial agents including BCC can be used with fluoride varnish to have sustained antibacterial activities.

The aim of this study was to examine the bioactivity and osseointegration of Ti-6Al-4V alloy implant which was modified by an anodic oxidation and a cyclic precalcification treatments. After blasting treatment using HAp (Hydroxyapatitie; HAp) powder which is resorbable blasting media (RBM) on the surface of Ti-6Al-4V alloy implants, the anodic oxidation treatment and the cyclic precalcification treatment were conducted to form nanotube TiO2 layer and HAp precipitation respectively. The surface morphology of the surface-treated Ti-6Al-4V alloy implant was investigated after immersion in the simulated body fluid(SBF) for 3 days to investigate the bioactivity. To investigate the effect of surface treatment on bonding between the implant and bone, RBM treated implant and RBM-anodization-cyclic precalcification(RACP) treated implant were placed on the distal side of both tibia diaphysis of rats, and then the removal torque of the implant was measured after 4 weeks. On the surface of RACP treated group, bone-like apatite precipitation was observed after immersion in SBF for 3 days. The removal torque was significantly higher in the RACP treated group than in the RBM treated group. The interfacial fracture between the implant and the new bone was observed in the RBM treated group, but both the cohesive fracture at the new bone and the interfacial fractures between the implant and the new bone were observed in the RACP treated group.
Alloys ; Animals ; Diaphyses ; Immersion ; Nanotubes ; Osseointegration ; Rats ; Tibia ; Torque

The calcium phosphate coating on various pretreated metals was prepared by soaking in modified simulated body fluid (m-SBF) solution. The coating structure and its surface morphologies were determined by x-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy. The results revealed significant differences in morphology and composition of the calcium phosphate coatings with and without chitosan and NaOH-pretreated commercially pure titanium (cp-Ti) substrate. The calcium phosphates formed on chitosan coated-Ti pretreated with NaOH were ~ 350 nm-sized resulting in strong bonding of the apatite layer with the substrates and a uniform gradient of stress transfer from coating materials to the Ti-substrate. After NaOH pretreatment, the hydroxyl groups bind to Ca²⁺ to attract PO₄³⁻ anions, eventually resulting in a continuous layer of calcium phosphate on chitosan coated-Ti substrate during immersion in m-SBF solution. The chitosan coated-Ti showed hydrophobic surface while NaOH pretreatment resulted in maximum hydrophilicity to the Ti substrate. Due to improved wettability of Ti by NaOH pretreatment before chitosan coating, aggregation of calcium phosphate was prevented and size-controlled composite materials were obtained.
Anions ; Body Fluids ; Calcium Phosphates ; Calcium ; Chitosan ; Clothing ; Hydrophobic and Hydrophilic Interactions ; Immersion ; Metals ; Microscopy, Electron, Scanning ; Spectroscopy, Fourier Transform Infrared ; Titanium ; Wettability ; X-Ray Diffraction

This study aimed to investigate whether pre-curing the universal adhesives affect the resin bonding to zirconia ceramic. Two commercial universal adhesives (All-Bond Universal, ABU; Single Bond Universal Adhesive, SBU) were tested in comparison with a conventional zirconia primer (Z-Prime Plus, ZPP). Air-abraded zirconia specimens were divided into six groups, to which different priming agents were applied with or without photo-polymerization. After resin cylinders were built on the primed zirconia surface using a resin cement (Duo-Link), all bonded specimens were stored in water at 37℃ for 24 hours and half of them (n = 12) were additionally thermocycled 5,000 times. A shear bond strength test was performed at a crosshead speed of 0.5 mm/minute and failure modes were assessed using an optical microscope at 25× magnification. Before thermocycling, the light-cured specimens of ABU and SBU showed higher bond strengths than the uncured ones of the materials (p<0.05), whereas no significant difference was found between the pre-cured and uncured specimens of ZPP (p > 0.05). After thermal aging, there were significant decreases in the bond strength for all specimens treated with the universal adhesives (p<0.05). However, ZPP produced no significant difference after aging (p > 0.05) and attained higher bond strength values for both the pre-cured and uncured specimens when compared to the two universal adhesives (p<0.05). Adhesive failures were predominant in all test groups and thermocycling resulted in the higher incidences of adhesive failures for the uncured groups, which was not shown in the pre-cured groups.
Adhesives ; Aging ; Ceramics ; Incidence ; Resin Cements ; Water

Objective of this study was to compare the color stability, mechanical and chemical properties of three different types of temporary crown resins. Commercially available powder-liquid (Group PL), light-cured (Group LC) and auto-mix syringe (Group AM) types' temporary crown resins were used as experimental groups for each of the evaluation. All the test groups were evaluated after 1 day and 7 days of immersion in various staining solutions. The colors of all groups before and after storage in the staining solutions were measured by a spectrophotometer based on CIE Lab system, and the color differences (ΔE(*)) thereby calculated. Micro hardness test was performed before water storage and aging after 7 days at 37 ℃. In addition, flexural strength, water sorption and solubility tests were performed according to international standard, ISO 10477. All experimental groups showed significant color change in staining solutions when compared to those stored in the control solution (distilled water) (p<0.05). Group PL showed the least color change among the three groups followed by Group AM (p<0.05). This tendency was observed after 7 days of immersion. In terms of the micro hardness test, Group PL showed the highest value among the three groups followed by Group AM (p<0.05). Additionally, the flexural strength decreased in the following order: AM > PL > LC (p<0.05). Water sorption and solubility increased in the following order: AM < PL < LC (p<0.05). The results of this study would provide useful information when choosing temporary crown resin types in various clinical situations.
Aging ; Crowns ; Hardness Tests ; Immersion ; Solubility ; Syringes ; Water

There are several causes of tooth discoloration following root canal treatment. In this study, we evaluated the effects of sealers on tooth discoloration and internal bleaching. Twenty-four teeth were divided into 4 groups: control group, AH plus, Endosequece BC, and MTA fillapex group. Root canal filling was performed using each sealer conventionally and non-vital bleaching was performed with sodium perborate. The L, a, and b values were measured using Vita easyshade. Tooth discoloration after root canal treatment occurs irrespective of the type of sealers and may cause discoloration with only gutta-percha cone. The effect of non-vital bleaching following the use of calcium silicate-based sealers such as Endosequece BC and MTA fillapex was higher than that of AH plus. Therefore, it needs careful use of sealers in endodontics and calcium silicate-based sealers have advantages of bleaching in case of discolored tooth.
Calcium ; Dental Pulp Cavity ; Endodontics ; Gutta-Percha ; Pemetrexed ; Sodium ; Tooth Discoloration ; Tooth