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Anomalies of jaw development
Last reviewed: 04.07.2025
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Developmental anomalies of the jaws can be congenital or occur as a result of illnesses, radiation therapy, or trauma.
Congenital clefts of the alveolar process and hard palate are the most common defect, they are recognized clinically. In 20-38% of cases, the defect is genetically determined. Clefts of the alveolar process and hard palate are often combined with dental anomalies (supernumerary, retained teeth, absence of rudiments), incorrect positioning of 4321234. With this anomaly, there is a delay in the formation of permanent teeth, underdevelopment of the alveolar process, and deformation of the nasal cavity. To recognize clefts, preference should be given to panoramic radiography.
Clefts of the hard palate may be combined with clefts of the soft palate and upper lip (in 50% of cases), may be complete or incomplete, unilateral or bilateral, localized in the area of the lateral incisor and canine, less often - between the central incisors, very rarely - along the midline of the lower jaw. Unilateral clefts usually have a flask-shaped form, bilateral ones are presented in the form of a slit-like enlightenment with even, clear contours.
Dysostosis is a disorder of bone development resulting from a hereditary familial disease of the skeletal system. The most important varieties are cleidocranial, craniofacial and maxillofacial dysostosis, hemifacial microsomia and Goldenhar syndrome.
Children with cleidocranial dysostosis have hypoplasia of the facial bones, jaws, mainly the upper jaw (the maxillary sinuses are underdeveloped), and the integumentary bones of the skull, combined with complete or partial underdevelopment of one or both clavicles. Non-closure or late closure of the cranial sutures or fontanelles, and a convex forehead are noted. A false impression of lower macrognathia (apparent enlargement of the lower jaw) arises. There are disturbances in the formation of roots, delayed eruption of primary and permanent teeth, and supernumerary teeth are common. There are disturbances in the formation of the pelvic bones, shortening of the fingers, and elongation of the metacarpal bones.
Craniofacial dysostosis is underdevelopment of the bones of the skull, brain, upper jaw, nasal bones, and pronounced lower macrognathia. Patients experience premature closure of cranial sutures, exophthalmos, strabismus, nystagmus, and visual impairment.
In the radiological picture of maxillofacial dysostosis (Franceschetti syndrome), the main symptom is bilateral underdevelopment of the zygomatic bones and zygomatic arches.
Bone and soft tissue abnormalities on the right and left sides may be expressed differently. A large mouth (macrostomia) gives the face a distinctive appearance - a "fish" or "bird" face, widely spaced eye slits, abnormal dental development, deformation of the auricles, and sometimes abnormalities of the middle and inner ear with conductive deafness. Changes in the maxillofacial region are combined with abnormalities of the chest and spine (supernumerary vertebrae, block of the upper cervical vertebrae). Dominant inheritance is noted.
Congenital malformations of the first and second branchial arches manifest as hemifacial microsomia and Goldeihar syndromes. The changes are unilateral and manifest as hypoplasia of the condylar process or condylar and coronoid processes of the lower jaw, zygomatic bone and arch, upper jaw and temporal bone. It is noted that the malformation of the lower jaw is a kind of indicator indicating changes in other bones of the skull. Such children also have developmental anomalies of the spine and urinary tract.
If congenital changes associated with malformations of the first and second branchial arches are suspected, orthopantomograms and radiographs in the chin-nasal projection are quite informative. When planning reconstructive surgeries, it is necessary to perform craniometry using teleradiograms. In children with Down syndrome, the first milk teeth appear only by the age of 4-5 years, sometimes remaining in the dental row until 14-15 years.
Children with decreased thyroid function experience delayed eruption of baby and permanent teeth, multiple dental caries, and underdevelopment of the jaws.
With insufficient activity of the anterior pituitary gland, the roots of baby teeth sometimes do not dissolve and remain for life, permanent teeth do not tend to erupt. Removal of baby teeth in these cases is not indicated, since one cannot be sure of the eruption of permanent teeth. Primary adentia occurs.
Hyperfunction of the pituitary gland at an early age causes increased root growth with a normal crown size, diastemas and tremas are formed, a reduction in the time of eruption and loss of temporary teeth, hypercementosis at the root tips is noted. There is a need to change removable and fixed dentures.
Post-traumatic deformations and deformations caused by osteomyelitis cause unilateral disruption of the occlusion of the teeth. In children and adolescents, injuries to the condylar process and joint can lead to the development of arthritis with disruption of the development of the corresponding half of the lower jaw on the affected side (micrognathia), and in adults - to arthrosis.
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