This paper presents a case of extreme tooth variation. The patient was first observed during the mixed dentition period, when she presented a mild Class II malocclusion with increased overjet and acceptable overbite. In a panoramic radiograph, the presence of lower second premolars of disproportionate dimensions was discovered. When these oversized premolars erupted, the Class I malocclusion tended toward Class III, with an edge-to-edge bite. This created an unstable occlusion and the possible need for extractions.