[Long-term observation of patients with trauma of the lower anterior primary teeth]

Three patients who had had trauma of the lower primary central incisors at the age of 1.5 years or less were observed with regard to the IIIB and/or IVA after eruption of the permanent dentition, and the findings were discussed from the viewpoint of space control. Patient 1 suffered shedding and loss of A perpendicular A following a fall downstairs at the age of 1.5 years. Measurement of the distance between B perpendicular B teeth revealed a tendency toward space closure and decrease until the age of 4 years and 6 months. At the age of 5 years and 11 months, the space was greater than that at the age of 4.5 years. The patient was also found to have brownish, partially parenchymatous defects of the permanent dentition, which were considered to be a sequela. Patient 2 suffered dislocation of A perpendicular A and root exposure at the age of 1 year and 1 month, and received treatment involving restoration and fixation for a 10-day period using a resin splint. Because of a fistula at the apical region of A and a discolored brown with internal resorption revealed by roentgenography, which were observed at the age of 4 years and 10 months, tooth extraction was performed and the course was observed with local space maintenance. When the patient was 6 years and 4 months old, eruption of 1 perpendicular 1 and hypoplasia of the labial surface were recognized. Since it proved possible to preserve A perpendicular A until the patient was 4 years old, the course was observed without any decrease in space until permanent dentition was accomplished. Patient 3 suffered shedding and loss of A perpendicular A at the age of 8 months. When the patient was 1 year and 3 months old, eruption of B perpendicular B occurred with mesial inclination. At the ages of 2 years and 7 months and 6 years and 4 months the patient underwent treatment with a space retainer and eruption of 1 perpendicular 1, respectively, without association of abnormal findings on the labial surface, probably because crown formation of 1 perpendicular 1 had not yet occurred due to the trauma suffered by the patient.(ABSTRACT TRUNCATED AT 400 WORDS)