Cephalometric characteristics of patients with different vertical facial patterns

Authors

Daniel Hou, University of the PacificFollow
Eric Le, University of the PacificFollow
Shivanesh Naicker, University of the PacificFollow
Kyra Lee, University of the PacificFollow
James Roblee, University of the PacificFollow
Joorok Park, University of the PacificFollow
Heesoo Oh, University of the PacificFollow

Lead Author Affiliation

Department of Orthodontics

Lead Author Program & Year

DDS Year 3

Presentation Category

Research

Introduction/Context/Diagnosis

The cephalometric analysis has been the gold standard for diagnosing anterior-posterior and vertical discrepancies. Utilizing MP-SN mandibular plane angles, we are able to categorize patients as hypo-divergent, normo-divergent, and hyperdivergent. The objective of this research project was to determine the cephalometric characteristics associated with these vertical facial patterns.

Methods/Treatment Plan

102 Class 1 occlusion patient cases participated in this study, with 34 cases each categorized in the following groups: hypo-divergent, normo-divergent, and hyperdivergent based on their MP-SN angle. There were an equal number of boys and girls in each group (17 males and 17 females). Females who were < 17 years of old, Males who were < 18 years old, and patients that had ANB values outside a normal class I range (-1.3 < N < 4.5) were excluded in this study. The orientation of the 3D volumes was achieved by locating 5 stable landmarks marks (completed by 1 rater). Following orientation, 41 landmarks were located including bilateral and midline structures. Each case was traced by two independent judges, both of which underwent calibration. From the traced landmarks 70 measurements were initially analyzed for significance through MANOVA and ANOVA testing. Significances were set at 0.05 and 0.0007. We followed up this significant ANOVA result with Tukey's HSD post-hoc testing (α=0.05).

Results/Outcome

Three measurements and a ratio showed statistically significant differences among the three groups (A: hypo-, B: Normo-, C: Hyper- divergent). For the High Vertical Mandibular Plane Angle cases, we noticed a smaller Mandibular ramus length (A>B>C), a more retrusive mandible via Nasion_Per_Pog (A, B>C), larger lower anterior facial height (C>A, B), smaller Ramus length/lower anterior facial height ratio (A>B>C).

Significance/Conclusions

There were statistically significant differences in Ramus length, Pogonion position, Anterior lower facial height measurements, and ramus length/lower anterior facial height ratio based on the different vertical facial patterns. Here we noticed that in the hyperdivergent cases, the patients presented a relatively retrognathic mandible forming a “pseudo” Class 2 profile. We can see that each vertical facial pattern has a strong correlation with specific cephalometric characteristics which could be utilized in treatment planning along with aiding in sleep apnea and airway correctional methodologies.

Format

Event