602 Growth Relationships Between the Mandible and Standing Height by Occlusion

Thursday, March 22, 2012: 3:30 p.m. - 4:45 p.m.
Presentation Type: Poster Session
D. MEIER1, R. STALEY1, and C. KUMMET2, 1University of Iowa, Iowa City, IA, 2Dows Institute for Dental Research, University of Iowa, Iowa City, IA
Objective: To measure longitudinal growth of the mandible and standing height from 6-13 years in Class I normal occlusions (CINO) and Class II malocclusions (CIIM), and correlate the variables to describe the strength of the associations in the occlusion groups.    


Cephalograms of 30 male and 28 female participants in the Iowa Growth Study were used [IRB approval].  Dial calipers were used to measure mandibular length between articulare-pogonion (Ar-Pg).  Standing height measurements were obtained from the Iowa Growth Study. Spearman correlations were used to correlate growth of standing height and articulare-pogonion in subjects with CINO (15 males and 15 females) and CIIM (15 males and 13 females).  The Fisher Z method tested for significant differences in correlation coefficients of growth measures.

Result: CINO correlation coefficients ranged from -0.01 to 0.7.  No CINO males had significant correlations but CINO females aged 9 and 10 had significant correlations (r=0.7235 p=0.0052, r=0.5804, p=0.0479).  CIIM correlation coefficients ranged from -0.2 to 0.8.  CIIM males age 13 and females age 11 had significant correlations (r=0.8333, p=0.0102, r=0.6993, p=0.0114, respectively). The only significant difference in correlations between the two occlusion groups occurred at age 9 in females (r=0.7235 [CINO]; r= -0.0070 [CIIM], p=0.0448).  Growth curves for mandibular length and for standing height were similar but key differences occurred in growth acceleration in both genders in both occlusion groups.  Conclusion:

Correlations between growth in standing height and length of mandible in CINO and CIIM subjects were low to moderate positive.  The correlations have minimal clinical application.  

Study support: University of Iowa Dows Research Award


Keywords: Growth & development, Human, Occlusion and Orthodontics
See more of: Craniofacial Anatomy
See more of: Craniofacial Biology