ABSTRACT
Objective@#This study evaluated the effect of cyclic pre-calcification treatment on the improvement of bioactivity and osseointegration of Ti-6Al-4V miniscrews. @*Methods@#The experimental groups were: an untreated group (UT), an anodized and heat-treated group (AH), and an anodized treatment followed by cyclic pre-calcification treatment group (ASPH). A bioactive material with calcium phosphate was coated on the mini-screws, and its effects on bioactivity and osseointegration were evaluated in in vitro and in vivo tests of following implantation in the rat tibia. @*Results@#As a result of immersing the ASPH group in simulated body fluid for 2 days, protrusions appearing in the initial stage of hydroxyapatite precipitation were observed. On the 3rd day, the protrusions became denser, other protrusions overlapped and grew on it, and the calcium and phosphorus concentrations increased. The removal torque values increased significantly in the following order: UT group (2.08 ± 0.67 N·cm), AH group (4.10 ± 0.72 N·cm), and ASPH group (6.58 ± 0.66 N·cm) with the ASPH group showing the highest value (p < 0.05). In the ASPH group, new bone was observed that was connected to the threads, and it was confirmed that a bony bridge connected to the adjacent bone was formed. @*Conclusions@#In conclusion, it was found that the surface treatment method used in the ASPH group improved the bioactivity and osseointegration of Ti-6Al-4V orthodontic miniscrews.
ABSTRACT
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 (p0.05). The group treated with MDP primer and tribochemical silica coating showed a significant difference in bond strength values after thermocycling (p0.05). 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.
ABSTRACT
The computer-aided design/computer-aided manufacturing (CAD/CAM) system was introduced to shorten the production time of all-ceramic restorations and the number of patient visits. Among these types of ceramic for dental CAD/CAM, they have been processed into inlay, onlay, and crown shapes using leucite-reinforced glass-ceramics to improve strength. The purpose of this study was to observe the mechanical properties and microstructure of leucite-reinforced glass-ceramics for dental CAD/CAM. Two types of leucite-reinforced glass-ceramic blocks (IPS Empress CAD, Rosetta BM) were prepared with diameter of 13 mm and thickness of 1 mm. Biaxial flexural testing was conducted using a piston-on-three-ball method at a crosshead speed of 0.5 mm/min. Weibull statistics were used for the analysis of biaxial flexural strength. Fracture toughness was obtained using an indentation fracture method. Specimens were observed by field emission scanning electron microscopy to examine the microstructure of the leucite crystalline phase after acid etching with 0.5% hydrofluoric acid aqueous solution for 1 minute. The results of strength testing showed that IPS Empress CAD had a mean value of 158.1±8.6 MPa and Rosetta BM of 172.3±8.3 MPa. The fracture toughness results showed that IPS Empress CAD had a mean value of 1.28±0.19 MPa·m(1/2) and Rosetta BM of 1.38±0.12 MPa·m(1/2). The Rosetta BM sample exhibited higher strength and fracture toughness. Moreover, the crystalline phase size and ratio were increased in the Rosetta BM sample. The above results are expected to elucidate the basic mechanical properties and crystal structure characteristics of IPS Empress CAD and Rosetta BM. Additionally, they will help develop leucite-reinforced glass-ceramic materials for CAD/CAM.
Subject(s)
Humans , Ceramics , Crowns , Crystallins , Hydrofluoric Acid , Inlays , Methods , Microscopy, Electron, ScanningABSTRACT
The aim of this study was to compare fluoride release and surface changes according to different orthodontic bracket adhesives the application of fluoride products. We used non-fluoridated composite resin Transbond fluoridated composite resins Blugloo and LightBond, resin-modified glass ionomer Rely XTM Luting 2, and conventional glass ionomer Fuji I®. Fluoride release of five orthodontic bracket adhesives and fluoride release ability after application of three fluoride products (1.23% acidulated phosphate fluoride gel, Tooth Mousse Plus®, Fluor Protector, and a toothbrush with sodium fluoride-containing toothpaste) were measured using a fluoride electrode that was connected to an ion analyzer. After 4 weeks of fluoride application, the surface roughness and surface morphology were examined using a surface roughness tester and field emission scanning electron microscopy. The amounts of fluoride release were observed not only on application of Tooth Mousse Plus® and Fluor Protector on resin-modified glass ionomer Rely XTM Luting 2 and Fuji I®, but also during tooth brushing using fluoride-containing toothpaste. After application of Tooth Mousse Plus®, except Transbond XT, the surface roughness increased, and all orthodontic adhesives showed a partial drop of micro-particle filler. On application of 1.23% acidulated phosphate fluoride gel on all orthodontic bracket adhesives, their surface roughness increased. To bond the orthodontic bracket, resin-modified glass ionomer Rely XTM Luting 2 and Fuji I® adhesives are highly recommended if the amount of fluoride release is considered to confer a preventative effect on dental caries, and among the fluoride products, Tooth Mousse Plus® and Fluor Protector are better than 1.23% acidulated phosphate fluoride gel, and these are expected to prevent dental caries even during tooth brushing with fluoride-containing toothpaste.
Subject(s)
Acidulated Phosphate Fluoride , Adhesives , Composite Resins , Dental Caries , Dental Cements , Electrodes , Fluorides , Glass , Microscopy, Electron, Scanning , Orthodontic Brackets , Sodium , Surface Properties , Tooth , ToothpastesABSTRACT
OBJECTIVES: The purpose of this study was to assess the effect of single and combined applications of fluoride on the amount of fluoride release, and the remineralization and physical properties of enamel. MATERIALS AND METHODS: Each of four fluoride varnish and gel products (Fluor Protector, FP, Ivoclar Vivadent; Tooth Mousse Plus, TM, GC; 60 Second Gel, A, Germiphene; CavityShield, CS, 3M ESPE) and two fluoride solutions (2% sodium fluoride, N; 8% tin(ii) fluoride, S) were applied on bovine teeth using single and combined methods (10 per group), and then the amount of fluoride release was measured for 4 wk. The electron probe microanalysis and the Vickers microhardness measurements were conducted to assess the effect of fluoride application on the surface properties of bovine teeth. RESULTS: The amount of fluoride release was higher in combined applications than in single application (p < 0.05). Microhardness values were higher after combined applications of N with FP, TM, and CS than single application of them, and these values were also higher after combined applications of S than single application of A (p < 0.05). Ca and P values were higher in combined applications of N with TM and CS than single application of them (p < 0.05). They were also increased after combined applications of the S with A than after single application (p < 0.05). CONCLUSIONS: Combined applications of fluoride could be used as a basis to design more effective methods of fluoride application to provide enhanced remineralization.