The present invention relates to a kit and a probe for detecting porous dental hydroxyapatite, comprising a protein capable of binding porous dental hydroxyapatite or a detector thereof. The invention also relates to a method for detecting a condition involving porous dental hydroxyapatite comprising detecting in or on a tooth or a sample of the tooth of a subject a protein bound to porous dental hydroxyapatite. The invention also relates to methods for detecting a hypomineralisation developmental dental defect or detecting intact and/or broken MIH enamel, and to a kit and method for removing a protein bound to porous dental hydroxyapatite.