 This study compared the retention rates of thermally cured, TC, and light cured, LC, custom bases attached to metal mini diamond brackets and clear spirit MB brackets, when used in indirect bonding procedures. The results indicated no significant differences in the retention rates of either of the custom base materials when used with metal brackets. However, the spirit MB brackets exhibited a significantly higher bonding failure rate when a TC custom base was used. It was therefore concluded that either material could be used in the indirect bonding of metal brackets, and that LC custom bases should be used in the indirect bonding of spirit MB brackets. This article was authored by Miles Peter G.