Evaluation of skeletal asymmetry in patients with posterior crossbites
Pancko, Nancy Kate
MetadataShow full item record
A posterior dental crossbite, in which one or more of the posterior teeth are locked in an abnormal coronal relationship with the opposing teeth of the opposite arch, is a common malocclusion that affects orthodontic patients. Early interceptive treatment is recommended for patients exhibiting a posterior dental crossbite, with a centric relation (CR) and centric occlusion (CO) shift, since it has been suggested that a prolonged mandibular shift resulting from dental interferences may result in an asymmetrical growth of one or both of the jaws. The purpose of this study was to determine if patients with an untreated skeletal and dental posterior crossbite display skeletal asymmetry based upon evaluation of a posteroanterior (PA) radiographic, utilizing constructed reference lines. Sixty subjects where selected from patient files from the State University of New York at Buffalo orthodontic clinic. Thirty patients, 14 years of age and older, were selected for the crossbite group if there was the presence of a dental crossbite involving at least two posterior teeth as well as the presence of a skeletal posterior crossbite, based upon Ricketts PA cephalometric analysis as a ratio of J-J to Ag-Ag less than 0.75. Using the above criteria, thirty patients, 14 years of age and older were selected for the control group if they had a Class I malocclusion without a dental crossbite and skeletal posterior crossbite, based upon Ricketts PA cephalometric analysis as a ratio of J-J to Ag-Ag greater than 0.75. Evaluation of cranial skeletal asymmetry was made on PA cephalograms utilizing constructed reference lines. The observed differences between the ratio (JR-JL/RAG-LAG) of the control and crossbite groups were statistically significant (F = 113.624, df = 1, 56, p ≤ 0.001). The results for length of Ag along the vertical reference line showed no significant differences (p>0.05) between the right, and the left sides of the females and the males for both the control and the crossbite groups. The results for the asymmetry index indicated no significant differences (p>0.05) between the control and the crossbite groups. The results for surface area of the triangle indicated that no significant differences existed between the right, and the left sides of the females and the males for both the control and the crossbite groups (p>0.05). The present study is in agreement with those studies that found no link between posterior crossbite malocclusion and asymmetrical growth. Additional studies need to be performed in order to investigate further the true impact that a posterior crossbite has on cranial skeletal structures.