The lack of a coherent program of dental prevention in recent years led to a multiplication of the patients with edentulous affections of 6-year molar. 6-year molar is the first definitive molar which erupts on the arch. Thus, corroborating also with other local and/or social causes, there comes out an early loss of this tooth. The consequences are both in the short term, but more serious are long-term ones. In this respect, it appears occlusal dysfunctions, changes in remaining teeth positions and last but not least, changes in aesthetics. This article is based on a number of X-ray computed tomography, with which it could establish a range of information about the quantity and quality of bone in the mandibular first molar area, taking into account the patient's age and first molar extraction time. It has been shown that bone offer is inversely proportional to the period elapsed from the moment of the first molar extraction.