The alveolar bone crest level is essential in determining the need for bone removal in subjects with altered passive eruption (APE). This study assessed the validity of CBCT and transgingival probing in determining the alveolar bone crest level. Patients presenting with APE were assessed. Transgingival probing was performed to clinically assess the distance between the cementoenamel junction (CEJ) and the bone crest at the midpoint of the maxillary anterior teeth. CBCT was used to assess this distance at the same point. Upon reflection of a full mucoperiosteal flap, the actual distance was measured. Similar actual and CBCT measurements of the distance between the CEJ and bone crest at teeth 13, 22, and 23 (FDI numbering system) were recorded (P > .05). However, in teeth 11, 12, and 21, the distance was significantly greater on CBCT scans (P < .05). No significant difference was detected between transgingival probing and the actual distance at all teeth assessed. Careful transgingival probing provides an accurate measure of the distance between the CEJ and bone crest. CBCT gives an accurate estimate, though it may not be justified for each patient in the presence of safer methods. [ABSTRACT FROM AUTHOR]