Prenatal and Postnatal Growth and Development of the Maxilla and Palate

The growth and development of an individual can be divided into two main periods: PRENATAL & POSTNATAL. The pre-natal period of development is a dynamic phase in the development of a human being, where the height increases by almost 5000 times as compared to only a threefold increase during the post-natal period.

Definitions and Concepts of Growth

To understand these processes, several experts define these biological changes as follows:

• According to Todd: “Growth is an increase in size” and “Development is progress towards maturity.”
• JX Huxley: The self multiplication of living substance.
• Krogman: Increase in size, change in proportion and progressive complexity.
• Meredith: Entire series of sequential anatomic and physiological changes taking place from the beginning of prenatal life to senility.
• Mayers: Quantitative aspect of biologic development per unit of time.
• Moss: Change in any morphological parameter, which is measurable.

Prenatal Development of the Maxilla

Development begins early in the embryonic phase. Around the 4th week of intra-uterine life, the developing brain and the pericardium form two prominent bulges on the ventral aspect of the embryo. These bulges are separated by the primitive oral cavity or stomodeum, the floor of which is formed by the buccopharyngeal membrane. The pharyngeal arches are laid down on lateral and ventral aspects of the cranial most part of the foregut. Specifically, the first arch is called the Mandibular arch and the second arch is the Hyoid arch.

The maxilla forms within the maxillary prominences. Ossification of the maxilla occurs slightly later than in the mandible, with the primary ossification centre appearing in the 7th week. Secondary centers include the zygomatic, orbitonasal, and nasopalatine centers. The primary center lies in the angle formed by the infra orbital nerve and anterior superior alveolar nerve. Ossification spreads through a bony trough formed for the infra orbital nerve and palatine process. Additionally, the maxillary sinus appears around the 16th week.

Associated structures like Meckel’s cartilage are derived from the first branchial arch around the 41st-45th day of intra-uterine life, extending from the cartilaginous otic capsule to the symphysis.

Development of the Palate

The palate develops from the maxillary processes and palatal shelves. During the mechanism of palate elevation, the palatal shelves initially grow vertically but then reorient horizontally and fuse in the midline. This process involves complex embryonic development and subsequent palate remodeling.

Postnatal Growth and Remodeling

Postnatally, the maxilla grows through processes like displacement, growth at sutures, and surface remodeling. Displacement is categorized into two types:

• Primary displacement: Resulting from the growth of structures like the maxillary tuberosity.
• Secondary displacement: Resulting from the growth of structures it is attached to, such as the cranial base.

Growth occurs at the sutures connecting the maxilla to the rest of the craniofacial complex. Surface remodeling increases the size and shape, facilitating overall growth in height, width, and length.