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Results indicate that tested orthodontic bonding composites are suitable for clinical application, but that further studies using different test methods are needed for Transbond XT.

) were prepared and the samples were extracted in 3 mL of Basal Medium Eagle with 10% newborn calf serum for 24 hours. The L929 cells were plated (25,000 cells/mL) in wells of 96-well dishes and maintained in a humidified incubator for 24 hours at 37uC, 5% CO 2 , and 95% air. After 24-hour incubation of the cells, the incubation medium was replaced by the immersed medium in which the samples were stored. Then L929 cells were incubated in contact with eluates for 24 hours. The cell mitochondrial activity was evaluated by the methyltetrazolium test. Twelve wells were used for each specimen, and methyltetrazolium tests were applied two times. The data were statistically analyzed using one-way analysis of variance and Tukey Honestly Significantly Different tests. Results:Results with L929 fibroblasts demonstrated that all freshly prepared resin-modified orthodontic band adhesive materials reduced vital cell numbers (P . .05), in comparison to the control group. Our data demonstrate that all materials showed significant cytotoxicity compared to the control group. Conclusions:The results indicate that all materials showed significant cytotoxicity compared to the control group, and further studies using different test methods are needed for all resin-modified orthodontic band adhesives. (Angle Orthod. 2010;80:890-895.)

Objective: To test the null hypothesis that there is no difference between the effects of fan-type rapid (FRME) and rapid maxillary expansion (RME) used with an acrylic bonded expansion appliance on dentofacial structures in early occlusal stages. Materials and Methods: This was a prospective clinical trial. The FRME group had an anterior constricted maxillary width with a normal intermolar width, and the RME group had bilateral constricted maxillary width. The FRME group consisted of 20 patients (mean age, 8.96 6 1.19 years), and the RME group consisted of 22 patients (mean age, 8.69 6 0.66 years). Lateral and frontal cephalometric radiographs and dental casts were taken before and after expansion and 3 months after completing treatment for each patient. The data were compared using repeated-measures analysis of variance. The paired-samples t-test was used to evaluate treatment and retention effects, and the independent samples t-test was used to consider the differences between the two groups. Results: The maxilla moved downward and forward in both groups. The nasal cavity and maxillary width were expanded more in the RME group, and there were only a few relapses in this group during the retention period. There was significant labial tipping of the upper incisors in the FRME expansion group. The expansion of intercanine width was similar in both groups, but the expansion of intermolar width was significantly greater in the RME group. Conclusion: The null hypothesis was rejected. There was a difference between the effects of FRME and RME used with an acrylic bonded expansion appliance on dentofacial structures in the early occlusal stages. (Angle Orthod. 2013;83:842-850.)