Although teeth microcracks have long been considered more of an aesthetic problem, their exact role in tooth structure and impact on its functionality is still unknown. The possibility to use X-ray micro-computed tomography for three-dimensional (3D) non-destructive tooth visualization has shown unique morphological and structural features of microcracks that previously could not be detected with two-dimensional analysis techniques. We present 3D evaluation of four healthy (2 with and 2 without visible microcracks on the buccal surface) extracted human teeth, scanned with ZEISS Xradia 520 Versa and segmented with convolutional neural network to identify enamel, dentin, and cracks. An intricate star-shaped network of microcracks was found to cover most of the inner tooth with the main crack planes arranged radially in two almost perpendicular directions, disclosing the crack as a planar rather than a threaded structure. The interconnected network of microcracks detected inside a healthy tooth suggests that the cracks could be considered as one of the structural and possibly functional (i.e. redistribution of forces) elements of the tooth, relevant for its integrity and functionality.