RESUMEN
OBJECTIVE: Clinical and histopathological evaluation of mechanical trauma on the development of maxillary first molar with Scanning Electron Microscope. DESIGN: Experimental study with four newborn Wistar rats. Trauma induced on 1st, 3rd, 7th and 10th postnatal days with dental K file. Right first molar region of the maxilla was the experimental side and the left side as control. Animals were sacrificed on the 42nd Postnatal day when the teeth came into functional occlusion. Teeth were evaluated clinically and SEM study of the crown was performed. RESULTS: Marked disfigurement of cusps, roughened defective, enamel, crown dilacerations and enamel hypoplasia were observed. Damage was less severe to the tooth subjected to trauma on the 10th postnatal day.