[Orthodontics problems of the first permanent molar tooth]

Following a series of theoretical considerations on normal occlusion, and on the interrelationship between the dentomaxillary apparatus and the central nervous system the authors approach two practical aspects:--the effects of an early loss of the first permanent molar tooth in the autochtonous child population, and--the solving of occluding changes in the sagittal plane. With regard to the first aspect a study was carried out in 246 patients aged between 11 and 18 years. In 48 of the subjects (19.51%) there was loss of the first permanent molar tooth, 26 had lost one tooth, and 22 had lost two teeth. Occluding changes were more marked when the lower molar teeth were lacking. With regard to the second aspect the authors present several cases of anomalies of the dentomaxillary apparatus with distal occlusion, solved in the Begg technique.