The research was carried out on 60 CBCT films of patients at the department of dentistry at Vietnam Cuba hospital. The goal was to determine the distance between the proximal root ana distal root of molars, between palatal roots of maxillary molars. Reasearch methodology: cross-sectional, describle study. On CBCT measured the distance' between the roots cutting at the apices and about one second of the roots. Results: The results indicated the distance between the proximal root and distal root of molars were: 1.6 teeth: 4,0 + or - 1,1 mm at
the apices and 2,3 + or - 0,7mm about one second of the root , 2.6 teeth: 4,2 + or - 1,3mm and 2,2 + or - 0,8mm, 3.6 teeth: 5,3 + or - 1,1mm and 3,6 + or - 0,7mm... Conclusion: The space for implantation of orthdontic anchorage screws between palatal roots of maxillary molars. The space for implantation of orthdontic anchorage screws between the proximal root and distal root of molars is the most dangerous.