The purpose of this study was to examine the dental and periodontal changes associated with orthodontic space closure of edentulous maxillary first molar areas in adults. The sample consisted of 20 quadrants from 18 patients. The pretreatment and posttreatment records included study casts, lateral cephalometric radiographs, and periapical or panoramic radiographs. Space closure averaged 5.3 mm. Eleven quadrants showed complete space closure, and nine quadrants averaged 1.0 mm of remaining space. Vertical bone loss averaged 1.2 mm mesial to and distal to the second molar and 0.6 mm distal to the second premolar. Although 60% of the quadrants showed <- 1.5 mm of bone loss, the maximal bone loss reached 4.0 mm mesial to, and 5.0 mm distal to, the second molar. Although space closure should be considered a potential solution in the absence of the first permanent molar, alveolar bone loss and space opening can be common sequelae to this procedure.