Description of the Case Report: 9-year-old male patient, presented at consultation because of excessive mobility in the permanent teeth. His mother wanted to have a second opinion, after he had been diagnosed with absence of the roots of the permanent teeth. The patient had no relevant background. Photographs and a panoramic radiograph were taken as complementary diagnosis exams. After analysing the radiography, the preliminary diagnosis is hypophosphatasia, as a result of the presence of two typical characteristics: enlarged pulp chambers and root defect. The proposted treatment is basically preventive and the prognosis is reserved. Discussion: Regular pediatric dental care from an early stage is recommended. Although there are many reports of hypophosphatasia in the literature, the documentation from a dental approach is scarce. In deciduous, mixed, and permanent dentition, the dental treatment must focus on rigurous dental hygiene and preventive diets in order to minimize the aggravation of the periodontal disease and the prevention of other diseases. Treatment can also include the substitution of exfoliated permanent teeth with, mainly, removable prosthesis. Careful monitoring is necessary to detect the progression of the periodontal disease, which can be indicative of the degree of systemic development. Conclusions: Hypophosphatasia is characterised by defects in dental and bone mineralization. It has genetic etiology, and affects both genders. The clinical manifestations are very variable and the earlier the onset age, the harsher its manifestations. Preventive methods are of extreme importance in these clinical cases. Schlagwörter: Hypophosphatase, alkaline phosphatase, hypophosphatasia