Crecimiento Craneofacial

Original Article

Mandibular Growth, Remodeling, and Maturation During Infancy and Early Childhood
Yi-Ping Liua; Rolf G. Behrentsb; Peter H. Buschangc
ABSTRACT Objective: To describe the growth, maturation, and remodeling changes of the mandible during infancy and early childhood. Materials and Methods: Seven Bolton-Brush Growth Study longitudinal cephalograms (N 5 336) of each of 24 femalesand 24 males, taken between birth and 5 years of age, as well as early adulthood, were traced and digitized. Five measurements and nine landmarks were used to characterize mandibular growth, remodeling, and degree of adult maturity. Results: Overall, mandibular length showed the greatest growth changes, followed by ramus height and corpus length. Corpus length was the most mature of the threelinear measures; ramus height was less mature than overall mandibular length. The greatest growth rates occurred between 0.4–1 year; yearly velocities decelerated thereafter. The ramus remodeled superiorly only slightly more than it remodeled posteriorly. Male mandibles were significantly (P # .05) larger, displayed greater growth rates, and were significantly less mature than female mandibles.There were no significant differences in mandibular growth or maturation between Class I and Class II patients. Conclusions: The mandible displays decelerating rates of growth and a maturity gradient during infancy and early childhood, with males showing more growth and being more mature than females. (Angle Orthod 2010;80:97–105.) KEY WORDS: Mandible; Maturation; Growth; Remodeling; Infancy; Earlychildhood

INTRODUCTION Although the craniofacial complex has been extensively studied,1–4 growth and development during infancy and early childhood remain poorly understood. It is, however, well established that the greatest postnatal rates of somatic growth occur during the first 5 postnatal years.5 US children, for example, undergo a marked deceleration of growth in recumbent length duringthe first 3 years (http://www.cdc.gov/ growthcharts).6 Based on the close associations between somatic and craniofacial growth and develPrivate Practice, St Louis, Mo. Professor and Chairman, Department of Orthodontics, Center for Advanced Dental Education, St Louis University, St Louis, Mo. c Professor, Department of Orthodontics, Baylor College of Dentistry, Dallas, Texas. Corresponding author:Dr Peter Buschang, Department of Orthodontics, Baylor College of Dentistry, 3302 Gaston Ave, Dallas, TX 75246 (e-mail: PHBuschang@bcd.tamhsc.edu)
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Accepted: April 2009. Submitted: February 2009. 2010 by The EH Angle Education and Research Foundation, Inc.
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opment,7–9 greater rates of craniofacial growth might also be expected during the first few postnatal years. Craniometricand anthropometric studies support the notion of marked craniofacial growth changes during the first 5 years.10,11,12 Ohtshuki et al13 reported greater cranial base growth during the first 5 postnatal years, especially during the first 2–3 years, than during the remaining postnatal years. While the studies are limited and the data fragmentary, mandibular growth also appears to be most rapid duringinfancy and early childhood. The ascending ramus dramatically changes its spatial relationship with the mandibular corpus during infancy, when the gonial angle decreases substantially.14 Mandibular ramus height and corpus length demonstrate higher growth velocities between 3 and 5 years than anytime thereafter.15 Based on a subsample of 32 subjects, Broadbent et al16 showed greatest growth ratesfor ramus height between 1 and 2 years of age, with rates decreasing thereafter. The greatest increases in bicondylar width have also been reported to occur during the first 3 years of life.17 The purpose of this study was to describe mandibular growth, remodeling, and maturational changes that occur during infancy and early childhood. The maturaAngle Orthodontist, Vol 80, No 1, 2010

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