The present invention relates to a method for cryopreserving the pulp of a non-exfoliated deciduous tooth, comprising a step of making with a laser a hole into the tooth removed from its physiological seat on the tooth neck. After making the hole, the tooth is contacted with a cryopreserving agent and then cryofrozen. An object of the invention further consists in mesenchymal stem cells isolated from the pulp of a cryopreserved tooth according to the method of the invention.