Dental occlusion is the term used to describe the relationship of the maxillary and mandibular teeth to each other when in contact and during function, as well as within each jaw. The American Academy of Pediatric Dentistry “recognizes the importance of managing the developing dentition and occlusion and its effect on the well-being of children, adolescents, and adults.” Such management requires appropriate and timely diagnosis of any developing malocclusion and the ability to either provide the proper treatment or refer the patient to the appropriate specialist for treatment, with the ultimate goal of obtaining a stable, functional, and aesthetically pleasing occlusion in the permanent dentition.
The pediatrician or family medical practitioner is uniquely positioned to clinically detect many malocclusions in the course of medical practice. Although a definitive diagnosis and treatment can be formulated only after a dentist acquires and evaluates the appropriate records, the primary healthcare provider should feel comfortable evaluating the occlusion and referring the child to a dentist when appropriate.
This chapter covers the stages of dental development, the development of a normal occlusion, and provides basic knowledge regarding the most common types of malocclusions seen in children.
DEVELOPMENT OF THE DENTITION
The normal sequence of tooth formation is outlined in Table 371-1. The earliest sign is seen at about the sixth week of embryonic life. The tooth buds of the primary teeth develop at 10 specific sites in each of the developing maxilla and mandible. The odontogenic epithelium that develops into tooth buds forms on the lateral aspect of the medial nasal process, the inferior border of the maxillary process, and the superior border of the mandibular process at approximately the same time that the first 2 embryonic processes fuse into the upper lip and the alveolar process. When this fusion fails or breaks down, a cleft lip and/or alveolus results, accompanied by various defects and differences in the developing teeth. The 20 succedaneous teeth develop beneath the primary teeth while the permanent molars develop distally (farther from the dental midline) in sequential order. Calcification of the primary teeth begins at about 4 months in utero, and the enamel of all primary tooth crowns is completely calcified by 10 months after birth. The permanent teeth begin to calcify with the first molar around the time of birth, and the process is complete for all the crowns of the teeth, with the exception of the third molars, by the seventh to eighth year of life.
Table Graphic Jump Location TABLE 371-1CHRONOLOGY OF THE HUMAN DENTITION ||Download (.pdf) TABLE 371-1CHRONOLOGY OF THE HUMAN DENTITION
|Tooth ||Hard Tissue Formation Begins ||Amount of Enamel Formed at Birth ||Enamel Completed ||Eruption ||Root Completed |
|Primary dentition |
|Central incisor ||4 mo in utero ||5/6 ||1.5 mo ||7.5 mo ||1.5 y |
|Lateral incisor ||4.5 mo in utero ||2/3 ||2.5 mo ||9 ...|