Comparison of orthodontic treatment outcomes in nonextraction, 2 maxillary premolar extraction, and 4 premolar extraction protocols with the American Board of Orthodontics objective grading system.
BACKGROUND
The aim of this study was to compare the orthodontic clinical outcomes of 2 maxillary premolar extraction, 4 premolar extraction, and nonextraction treatment protocols.


METHODS
The sample for this retrospective study was selected randomly from the archives of postgraduate orthodontic clinics in various cities in Turkey. Posttreatment records including dental casts and panoramic radiographs of 1098 patients were divided into 3 groups: group 1 comprised 269 patients treated with 2 maxillary first premolar extraction, group 2 comprised 267 patients treated with 4 premolar extraction, and group 3 comprised 562 patients treated with a nonextraction protocol. Only 1 researcher evaluated all subjects using the American Board of Orthodontics objective grading system.


RESULTS
There were no statistically significant differences among the 2 maxillary premolar extraction, 4 premolar extraction, and nonextraction treatment groups for alignment, marginal ridge height, buccolingual inclination, overjet, and interproximal contact measurements. Statistically significant differences were found in occlusal contacts, occlusal relationships, and root angulation measurements between the 4 premolar extraction and the nonextraction groups.


CONCLUSIONS
The nonextraction patients had more teeth in occlusion than did the 4 premolar extraction patients. The nonextraction patients finished with more satisfactory sagittal dental relationships. The 4 premolar extraction group had the least satisfactory sagittal dental relationships. The nonextraction patients finished with better root angulations.
Research assistant, Department of Orthodontics, Faculty of Dentistry, Izmir Katip Celebi University, Izmir, Turkey.
Hatice
H
Akinci Cansunar
Professor and chair, Department of Orthodontics, Faculty of Dentistry, Izmir Katip Celebi University, Izmir, Turkey. Electronic address: tancanuysal@yahoo.com.
Tancan
T
Uysal
D000293:Adolescent; D000539:Alveolar Process / Q000473:pathology; D001641:Bicuspid / Q000601:surgery*; D002985:Clinical Protocols; D003766:Dental Occlusion; D005260:Female; D006801:Humans; D008297:Male; D008310:Malocclusion / Q000628:therapy; D008437:Maxilla / Q000473:pathology; D003765:Models, Dental; D009971:Orthodontics, Corrective / Q000592:standards*; D057887:Overbite / Q000145:classification; D011862:Radiography, Panoramic; D012189:Retrospective Studies; D013997:Time Factors; D014070:Tooth / Q000473:pathology; D014081:Tooth Extraction / Q000145:classification*; D014092:Tooth Root / Q000473:pathology; D016896:Treatment Outcome