dimensional changes of dental arch following nonextraction orthodontic treatment

Introduction: since the emergence of normal occlusion concept, selecting an appropriate treatment plan with or without tooth extraction has been a controversial subject. nowadays, both methods can be successfully used for treatment of patients. however, some clinicians still believe that nonextraction orthodontic treatments have fewer complications. the purpose of this study was to evaluate dental arch dimensional changes following nonextraction orthodontic treatment.materials &methods: a total of 200 pre and posttreatment diagnostic dental casts belonging to 100 patients (nonext treated by 0.18 roth system) who met the inclusion criteria for this study were collected from the archives of shahid beheshti dental school. sampling was nonrandomized. a digital caliper with the accuracy of 0.1 mm was used for the measurement of variables such as intercanine width , interpremolar width and intermolar width.results: nonextraction orthodontic treatment increased all the variables, except for the mandibular intercanine width and incisorcanine distance.conclusion: nonextraction orthodontic treatment causes a significant increase in almost all dental arch parameters. this increase manifests as teeth flaring.