Effect of serial extraction alone on crowding: Spontaneous changes in dentition after serial extraction

We examined changes in dentition after serial extraction in subjects who wo re no appliances to determine the relationships between changes in dentitio n and improvement in dental crowding, Mandibular dental casts and lateral c ephalograms from 31 subjects who had undergone serial extraction without or thodontic treatment were analyzed at 3 stages: before extraction of the dec iduous canines (TI), after extraction of first premolars (T2), and at the e nd of the observation period (T3), Although movements of the first molar cu sp and apex from T2 to T3 were significantly greater than from T1 to T2, mo vements of the incisor cusp and apex from T1 to T2 were significantly great er than from T2 to T3, The first molar tipped mesially from T1 to T2 but ti pped distally from T2 to T3, The distal tipping of the incisor from T1 to T 2 was significantly greater than from T2 to T3, These results suggest that the main changes in dentition from T1 to T2 are different from those from T 2 to T3. The correlations between the annual change in the canine movement or tipping from T2 to T3 and the annual change in the irregularity index at the same time were significant. These results suggest that the canine move ment or tipping contributed to the correction of the anterior crowding from T2 to T3.