In-vivo evaluation of clinical bracket failure rate of two different pre-coated brackets

The aim of this in vivo study is to evaluate the clinical bracket failure rate of two different precoated brackets. Thirty-three patients (7 males and 26 females) with a mean age of 17,2±3,6 years with permanent dentition without any prior orthodontic treatment with dental Class I or mild Class II anomalies were included in the study. Six hundred and sixty brackets (APC Flash Free and APC Plus brackets ) were bonded by one operator using a split-mouth design with using phosphoric acid and bracket failure rates were observed during 6 months. The chair time required for bonding of each qudrant was also evaluated. The survival rates of the brackets were evaluated by using the chi-square and Kruskal-Wallis test. Required chair time for each quadrant was evaluated by using One way ANOVA and Tukey HSD test. The overall (10 brackets) and APC Flash Free (4 brackets) and APC Plus (6 brackets) bracket failure rates were 1.5, 1.2 and 1.8 per cent respectively. Chi-square test was revealed significant differences (Chi-square =24.783, p=0.0008) between groups related with the bracket failure rates. Upper left APC Plus group was showed statistically significant (Kruskal-Wallis test statistics: 1,1077 ; p=0,0008) more failure rate than the other groups according to Kruskal-Wallis test. Chi-square test was not revealed significant differences (Chi-square =1,667, p=0.435) between groups related with ARI scores. One way ANOVA test (F=17,167 ; p<0,001) was showed statistically significant differences between groups according to the required chair times for bonding the brackets. The shortest time was obtained from lower left APC Flash Free group (4,84 ± 0,53 minutes), while the longest time required to bond the brackets (6,36 ± 0,45 minutes) was seen in the upper left APC Plus group. Bonding the APC Flash Free brackets in all quadrants was required statistically significantly less chair time. Since the failure rates of two different APC brackets were clinically acceptable, they are recommended for clinical application. However less chair time required for bonding and less failure rate results obtained from APC Flash Free brackets makes this bracket more useful in clinical practice. On the other hand, more sample sized microbiological studies including different type of enamel conditioning methods are needed for evaluating the long term effects of these brackets on enamel and oral microbial flora.