Normal and abnormal growth of the mandible. A synthesis of longitudinal cephalometric implant studies over a period of 25 years

TLDR

The mandibular corpus and its soft‑tissue matrix act as independent systems whose forward and backward rotations can be decomposed into total, matrix, and intramatrix components that vary throughout development. This paper investigates the complex rotation processes occurring during normal and abnormal mandibular growth. By partitioning mandibular rotation into these components, the authors can quantify the substantial remodeling occurring at the lower border of the mandible. Orthodontic treatment modifies the rotation components and remodeling of the mandible, and the results demonstrate that matrix and bone develop independently rather than the matrix dominating bone formation.

Abstract

This paper examines the complex rotation processes that occur during growth in normal and abnormal mandibular development. The bony mandibular corpus and its soft tissue covering, the matrix, are considered as independent tissue systems capable of independent rotation. Both forward and backward rotation can be divided into three components: the total rotation, the matrix rotation, and the intramatrix rotation, showing different individual interrelationships and a changing composition in each individual during the entire period of development. Dividing the mandibular rotation into these components permits measurement of the, often considerable, remodelling at the lower border of the mandible. Orthodontic treatment influences the components of mandibular rotation and thus induces a change in the remodelling of the mandible. The findings do not support the view that the matrix is a dominating factor and that bone formation is secondary in mandibular growth, but point to considerable independence in development of the two tissue systems.