IADR Abstract Archives
Clustering of the Mandibular Symphysis in Skeletal Class III Patients.
Objectives: The aim of the present research is to create a symphysis clustering model on skeletal class III patients in order to move towards a more predictable and individualized treatment for this malocclusion.
Methods: 250 skeletal class III patients diagnosed at the Orthodontics Master Programme of the School of Dentistry of the Complutense University of Madrid were selected. After verifying that the patient meets the inclusion criteria, a total number of 3000 radiometric landmarks were identified on the symphysis region of the lateral rxs. The ICC was evaluated by analyzing the variances of the different measurements (ANOVA) and the Dahlberg's formula was used to quantify the error between T0 and T1 measurements. A principal component analysis (PCA) was performed to group the set of variables into subgroups, which allowed the creation of a cluster analysis.
Results: Three clusters were identified in the context of skeletal class III malocclusion. The cluster A, is characterized by a high width/height ratio of the symphysis, marked anterior prominence, reduced convexity and greater cortical and cancellous bone thickness than the other groups. Cluster B, is defined by the inclination of the alveolar portion, and determined by the inclination of the incisor and the high thickness of the cancellous bone portion. Finally, cluster C is characterized by a smaller width/height ratio, smaller anterior projection and alveolar inclination. It also has a reduced thickness of both cortical and cancellous bone.
Conclusions: Different clusters at symphysis morphology might conditionate treatment decision for both growing patients and those who are going to undergo combined orthodontic and orthognathic surgery treatment, this should be elucidated in future longitudinal research.
Methods: 250 skeletal class III patients diagnosed at the Orthodontics Master Programme of the School of Dentistry of the Complutense University of Madrid were selected. After verifying that the patient meets the inclusion criteria, a total number of 3000 radiometric landmarks were identified on the symphysis region of the lateral rxs. The ICC was evaluated by analyzing the variances of the different measurements (ANOVA) and the Dahlberg's formula was used to quantify the error between T0 and T1 measurements. A principal component analysis (PCA) was performed to group the set of variables into subgroups, which allowed the creation of a cluster analysis.
Results: Three clusters were identified in the context of skeletal class III malocclusion. The cluster A, is characterized by a high width/height ratio of the symphysis, marked anterior prominence, reduced convexity and greater cortical and cancellous bone thickness than the other groups. Cluster B, is defined by the inclination of the alveolar portion, and determined by the inclination of the incisor and the high thickness of the cancellous bone portion. Finally, cluster C is characterized by a smaller width/height ratio, smaller anterior projection and alveolar inclination. It also has a reduced thickness of both cortical and cancellous bone.
Conclusions: Different clusters at symphysis morphology might conditionate treatment decision for both growing patients and those who are going to undergo combined orthodontic and orthognathic surgery treatment, this should be elucidated in future longitudinal research.