Maxillary premolar extraction--a possible link to later periodontal breakdown?

The palatal embrasure angles between the maxillary first molar and adjacent premolar were measured in 60 children who had had orthodontic treatment (29 with premolar extractions and 31 without), and in 20 adults with periodontal breakdown in the palatal embrasure angle area, who had had premolar extractions. Mean angles were orthodontic groups non-extraction 31 degrees, extraction 42 degrees and the adult group, 57 degrees. Statistical analysis showed significant differences between the groups. A wide palatal angle between maxillary first molar and adjacent premolar appears to predispose to periodontal breakdown in the area. Rotation of teeth which open the palatal embrasure angle should be minimized.