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Comparison of Bond Strength of Metal and Ceramic Brackets Professional

منذ 9 أشهر Multimedia Saïda   155 الآراء

-- دج

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موقعك: Saïda
السعر: -- دج

MIM bondable metal bracket with a nominal base area of 15.1mm 2 were bonded to the etched enamel and other steps were performed similar to group A. The adhesive was high-power light-cured for three seconds (1.5 seconds from mesial and 1.5 seconds from distal).

Group C: Metal brackets (American Orthodontics, Sheboygan, WI, USA) with a nominal base area of 11.3mm 2 were bonded to the etched enamel and other steps were performed similar to other groups. The adhesive was light-cured conventionally (600 mW/cm 2 ; Dr’s light, Good Doctors Co., Ltd., Incheon, South Korea) for 20 seconds (10 seconds from mesial and 10 seconds from distal).

Group D: Ceramic brackets (American Orthodontics, Radiance Plus, Sheboygan, WI, USA) with a nominal base area of 15.1mm 2 were bonded to the etched enamel and other steps were performed similar to other groups. The adhesive was light-cured conventionally for 20 seconds (10 seconds from mesial and 10 seconds from distal). The samples were mounted in a metal mold containing auto-polymerizing acrylic resin and thermocycled for 2,500 cycles between 5–55°C for 20 seconds at each temperature with 20 seconds of transfer time. Rectangular wires were used to match the central alignment of teeth in acrylic resin. All samples were subjected to SBS test in a universal testing machine (7060; Zwick Roell, Ulm, Germany) at a crosshead speed of 3 mm/minute (Fig. 1).

The results were obtained in kilogram-force, converted to Newtons and then to megapascals (MPa). After failure, the samples were observed under a stereomicroscope (SMZ 800; Nikon, Tokyo, Japan) at ×20 magnification to score the amount of remaining adhesive using the adhesive remnant index (ARI) [29]: 0=No adhesive remained on the tooth; 1=Less than 50% of adhesive remained on the tooth; 2=50% or more of the adhesive remained on the tooth surface; 3= 100% of the adhesive remained on the tooth, with a distinct impression of bracket mesh, corresponding to failure at the bracket-adhesive interface. Data were statistically analyzed using SPSS version 22.0.0 (SPSS Inc., Chicago, IL, USA).

The mean, standard deviation, minimum and maximum values of SBS of metal and ceramic brackets to tooth surfaces using two models of light-curing units were computed and reported. The SBS data were analyzed using one-way ANOVA, followed by Tukey’s post hoc test. Failure mode data were subjected to Kruskal-Wallis nonparametric test, followed by LSD post hoc test. Statistical significance was set at alpha=0.05.