Clinical Evaluation of Glass Ionomer Cement as an Adhesive for the Bonding of Orthodontic Brackets

Abstract

Glass ionomer cement has been shown in previous studies to retard decalcification and caries formation. This cement would be valuable in orthodontics if it proved to have adequate adhesive properties. Therefore, this study was designed to determine if there is a significant difference in the failure rate of brackets attached to teeth using a glass ionomer cement, Ketac-fil, and the failure rate of brackets attached to teeth using a conventional orthodontic adhesive system, Rely-a-bond. Six patients in the Department of Orthodontics at Indiana University School of Dentistry participated in this study. Each patient had 16 to 20 teeth available for bracketing. Direct-bond orthodontic brackets were attached to one-half of each participant's available teeth using Ketac-fil. Rely-a-bond was used to bond brackets to the remaining half of the teeth. Fifty-three brackets were placed with Ketac-fil, and 53 with Rely-a-bond. This study lasted a minimum of ten weeks for each patient. The following observations were made:

The failure rates for brackets attached with Ketac-fil and those attached with Rely-a-bond. The type of bracket failure for brackets bonded with Ketac-fil. Pre-study and post-study decalcification patterns of teeth with brackets attached with Ketac-fil.

The bracket failure rate was 3.77% for the Ketac-fil group and 5.66% for the Rely-a-bond group. There was no significant difference between the failure rates of these two groups at the alpha = 0.05 level when tested with the Fisher Exact Probability Test. Of the two brackets that failed in the Ketac-fil group, only one was available for examination and it demonstrated a definite adhesive type of bracket failure. With respect to decalcification patterns, no obvious change in pattern occurred for teeth in the Ketac-fil group. There was no statistical difference between the failure rates of brackets attached with Ketac-fil and those attached with Rely-a-bond. Previous studies have shown that glass ionomer cements release fluoride and that this may retard decalcification and caries formation. Decalcification and caries formation around the margins of orthodontic brackets have been identified as potential risks of orthodontic treatment. Thus, the use of a glass ionomer cement as a bonding agent in orthodontics might reduce these potential risks without compromising the attachment of the brackets to teeth. This study provides the basis for more extensive clinical trials of glass ionomer cements as bonding agents for direct-bond orthodontic brackets.