Orthodontic Malocclusion Types and Craniofacial Syndromes

Classified in Biology

Written on March 1, 2026 in English with a size of 4.83 KB

Orthodontic Classifications

Class II, Division 1: Characterized by proclined upper incisors, lingual inclination of lower incisors, and a deep overbite. It often features a V-shaped palate, mandibular deficiency, abnormal muscle pressure, and mouth breathing.
Class II, Division 2: Characterized by upper central incisors with lingual overlap by the lateral incisors and a deep overbite. It features a square upper arch, normal muscle pressure, and no mouth breathing.

Class 1: The upper canine occludes in the embrasure between the lower canine and the first premolar.
Class 2: The upper canine occludes anteriorly, between the lower canine and the lateral incisor.
Class 3: The upper canine occludes posteriorly, between the fourth and fifth teeth (premolars).

Class 1: The lower incisor edges occlude below the cingulum of the upper incisors.
Class 2, Division 1: Proclined upper central incisors with an increased overjet.
Class 2, Division 2: Retroclined upper central incisors with an increased overbite.
Class 3: The lower incisor edges lie anterior to the cingulum of the upper incisors.

Achondroplasia: Growth centers in long bones and the cranial base do not function correctly. Symptoms include short arms and legs, a large face and forehead, Class III malocclusion, midface deficiency, and relative mandibular prognathism.
Craniofacial Dysostosis (Crouzon Syndrome): Premature fusion of posterior and superior maxillary sutures along the orbit. Symptoms include shallow orbits, protruded eyes, open bite, spaced teeth, Class III malocclusion, midface deficiency, and relative mandibular prognathism.
Cleidocranial Dysostosis: Characterized by the absence of clavicles, anodontia (missing teeth), supernumerary teeth, cleft palate, and relative mandibular prognathism.
Hemifacial Microsomia: A vascular problem causing poor blood supply to the face during development. It results in a lack of tissue on the affected side, deviation toward the affected side, and orbit distortion.
Mandibulofacial Dysostosis (Treacher Collins Syndrome): Underdeveloped lateral orbit rims and zygomatic areas, cleft palate, eye and ear problems, and an underdeveloped mandible. It often results in Class II malocclusion, airway problems, and mandibular hypoplasia.
Cleft Lip and Palate: Congenital split in the upper lip or the roof of the mouth.

Teratogens: Environmental agents causing developmental malformations.
Fetal Molding and Birth Injuries: Physical trauma, such as injuries from obstetric forceps.
Systemic Diseases: Rickets, caused by Vitamin D deficiency, leads to soft bones, a bulging forehead, bowing legs, an open bite, and caries in deciduous teeth.
Endocrinal Disorders:
- Hyperpituitarism (Acromegaly): A tumor in the anterior pituitary gland causing excess growth, leading to mandibular prognathism and Class III malocclusion.
- Hypothyroidism: Decreased thyroid hormone levels leading to delayed tooth eruption.
Respiratory Issues: Mouth breathing due to obstruction of the nasal airway, often resulting in "adenoid face."
Malnutrition: Nutritional deficiencies affecting dental and skeletal development.
Idiopathic Causes: Hemimandibular Hypertrophy involves unilateral excessive growth of the mandible, typically in girls. It causes facial asymmetry, deviation of the mandible toward the healthy side, an open bite, and an enlarged condyle on the affected side.

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