| Objectives:The changes of roughness on porcelain veneer from with the orthedontic brackets was removed and polished atcs observed.Methods:1. Porcelain-metal discs'preparation:Manufacture round porcelain-metal discs of three millimeter in thickness and 10 millimeter in diameter, consisting of one illimeter Ni-Cr metal and two millimeter porcelain.2. Porcelain surface treatment:Divided the porcelain-metal discs into five groups at random, and treated by five different methods.Group 1:The samples were a coarse diamond roughed, washed by high steam for 5 minutes, and dried.Group 2:The samples were HF acid 10% was applied for 1 minutes, washed for 1 minute, and dried.Group 3:First, the samples were a coarse diamond roughed, washed by high steam for 5 minutes, and dried. Then HF acid 10% was applied for 1 minute, washed for 1 minute, and dried.Group 4:The samples were sandblasted with 50μm luminum oxide (Al2O3),80 n/m2, part form 10 mm, for 10 seconds with an intraoral sandblaster, washed with absolute alcohol for 3 minutes, washed for 1 minute, and dried.Group 5:First, the samples were sandblasted with 50μm aluminum oxide (Al2O3),80 n/m2, part form 10 mm, for 10 seconds with an intraoral sandblaster, washed with absolute alcohol for 3 minutes, washed for 1 minute, and dried. Then HF acid 10% was applied for 1 minute, washed for 1 minute, and dried. All samples were bonded by Jingjin enamel adhesive and stored in water for 24 hours and thermocycled 500 times between 5℃and 55℃. The bracket were removal with shearing force. After debonding, residual adhesive resin was removed in a slow-speed handpiece. Adhesive removal was performed until a visually smooth surface was obtained. The samples were polished using porcelain adjustment kit (Shofu, Japan) The adjustment kit consisted of four discs with different grain size, which were used until the smoothness was obtained. New discs were applied to each sample. All polishing procedures were performed by the same operator using a slow-speed handpiece, as recommended by the manufacturer. In addition, these procedures were performed until the surfaces appeared shiny to the naked eye, simulating the clinical conditions. The polishing materials and using method:①Dura-White Stone for adjusting,5,000 r.p.m;②Cermiste Standard Polishers for perpolishing,10,000 r.p.m;③Ultra I Polishers for polishing,10,000 r.p.m;④UltraⅡPolishers for superpolishing, 10,000r.p.m.3. The detemination of sample surface's roughnessDetemined the central of the samples for the surface roughness, ever sample change three different directions, and taking the mean statistical analysis. Spss16.0 software analysis results. Stylus type surface roughness with TALYSURF112 Meter(British taylor), Sampling the length of 0.8 mm, assess the length of 3.2 mm, speed 0.25 mm/s, measured centerline average roughness value of Ra.Results:1. Different Methods of rough treatmentSpss16.0 statistical software with the experimental results SNK-q test (multiple of the mean of the couple comparison). Each group in the Group 3 and group 1, group 2, group 4,5 group method of rough treatment significantly (P<0.05); while Group 1, group 2, Group 4, Group 5 coarsening treatment method was no significant difference (P> 0.05).Further comparison between Group 1, group 2, group 4, Group 5 of the coarsening approach, while Group 4 and group 1, group 2, Group 5 coarsening difference in treatment was statistically significant (P<0.05); while Group 1, group 2, Group 5 Rough treatment method was no significant difference (P> 0.05).2. Polishing roughness among the three groups before and after comparison ofSpss16.0 statistical software with the experimental results SNK-q test. Group 1, group 2, Group 5 no significant difference between (P> 0.05); and section 3 groups and Group 4 were compared with the other groups was statistically significant difference (P<0.05).3. After polishing roughness compared with the control groupSpss16.0 statistical software with the experimental results are paired t test (multiple of the mean of the couple comparison). Comparisons among the three groups no statistically significant difference (t> 0.05).Conclusion:1. In the porcelain surface rough treatment methods, the mechanical fininshing with hydrofluoric acid etching method of combination of rough surface on the porcelain of the best, followed by mechanical fininshing, hydrofluoric acid etching and sandblasting etching with hydrofluoric acid in combination option, while a separate method of use of sandblasting to do rough porcelain surface treatment of the effects of the worst.2. The porcelain surface roughness value of large, by polishing the surface roughness the greater the value changes. The more polished approach to the more obvious effects of rough surface.3. After remove the brackets, polishing can make the porcelain surface level approximation before treatment. |
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