Etiology of Malocclusion

Vocabulary flashcards about the etiology of malocclusion based on lecture notes.

Etiology (in orthodontics)

The study of the actual causes of dento-facial abnormalities.

Malocclusion

Deviation from the usual or accepted dental occlusion or occlusal relationship. Abnormal relation of individual teeth within one or both jaws.

Orthodontic Equation

Expression of the development of any dento-facial deformity: Cause acts at a certain time on tissue produces results

Primary Etiologic Sites

Neuromuscular system, Bone and Teeth

Neuromuscular system role in Etiology

The effect of abnormal contraction of the bony skeleton and the dentition.

Evolution and Malocclusion

Smaller jaws, reduction in number and size of teeth and diminution of jaw projections together with increased in vertical height of the face and there is a retrognathic tendency in mans

Heredity

Transmission of dentofacial characteristics through generations by genes.

Repetitive Transmission

The recurrence of single dentofacial deviation within the immediate family

Discontinuous Transmission

A tendency for mal-occlusal trait to reappear within the family over several generation

Variable Transmission

The occurrence of different but related types of malocclusion within several generation of the same family

Cleft Palate

Lack of fusion of two palatal process to each other

Cerebral Palsy

A paralysis or lack of muscular coordination due to inter-cranial lesion.

Torticollis

Wryneck. Foreshortening of the sternocleidomastoid muscle

Cleidocranial Dysostosis

Congenital defect characterized by unilateral or bilateral complete or partial absence of the clavicle, delayed closure of cranial suture, maxillary retrusion, mandibular protrusion, retarded eruption of permanent teeth

Mandibulo-facial Dysostosis

Characterized by hypoplasia of facial bones especially zygomatic and mandible, bird face appearance, crowding and malposition of teeth, agenesis of malar and palatine bone

Micrognathia

Abnormal small jaws maxilla or mandible may be affected

Macrognathia

Abnormally large jaw, may be true due to the actual prognathism of jaw or relative due to underdevelopment of one jaw(maxilla) to the other

Pierre Robin’s Syndrome

characterized by Micrognathia, glossoptosis, cleft palate

Tongue Tie

Congenital condition caused by shortness or excessive anterior prolongation of Frenum linguae of the under surface of tongue.

Ankylglosum Superior Syndrome

Rare condition characterized by Tongue congenitally attached to the hard palate or maxillary alveolar ridge, Hypodontia Microglossia and Anomalies of extremities

Microcephaly

Congenitally anomaly in which the brain development is retarded, and it is smaller than normal.

Hydrocephaly

Spinal fluid fills the cranium and causes the enlargement of cranial vaults

Craniostenosis

Sutures of the cranial vault may be fuse prior to the complete growth of brain depending on the sutures involved.

Platybasia

Occur as in case of mongolism, the angle between the anterior cranial base and posterior cranial base is obtuse angle in such degree to appear as straight line

Microglossia and Aglossia

Rare condition characterized by small or rudimentary tongue, aglossia is very rare condition in which the tongue is completely absent

Macroglossia

Abnormal large tongue

Macrochelia

Enlarged lower lip, flaccid and everted

Hypertelorism

Characterized by lateral position of eye due to widening of the bridge of the nose; incomplete development of maxillary process; incomplete development of mandibular rami

Rubella

Acute viral infection usually occurs in epidemic form, maternal rubella of pregnant mother is considered as a possible cause of wide spread congenital malformation

Birth injuries

With high forceps delivery is common and may cause ankylosis of TMJ which effect the condylar growth center and thus interfere with normal mandibular growth

Hypo-pituitarism

pituitary dwarfism. delayed eruption and shedding time of teeth, root of the teeth is shorter than normal, dental arch is smaller than normal, retarded osseous development of mandible than maxilla, delayed apical closure

Hyper-pituitarism before puberty

Gigantism. root of teeth longer than normal, upper part of body is shorter than normal, spacing of teeth, ossification of cartilaginous center is delayed

Hyper-pituitarism after puberty

Acromegaly. lips are thick and negroid, tongue enlarged and show indentation, teeth in mandible are tipped buccal or labial due to enlarged tongue, mandible is large size due to accelerated condylar growth

Hypothyroidism: congenital type

Cretinism. Failure of thyroid gland to produce sufficient hormone to meet the requirement of the body. shortening of the base of skull, mandible is under-developed, maxilla is over-developed (relative), retardation in normal rate of deposition of calcium in bones, defect facial height, tongue enlarged and protruded delays shedding and eruption

Hyperthyroidism

Hyper-function of thyroid gland. alveolar atrophy in advanced cases, shedding of deciduous teeth is earlier than normal, accelerated eruption of permanent teeth

Hyper-parathyroidism

Von RecklinghausenÕs disease of bone. High osteoclastic activity and withdrawal of calcium from the bony skeleton due to bone resorption, sudden drifting of teeth that lead to spacing

Hypo-parathyroidism

low calcium level below 10mg/100ml. increase neuromuscular excitability ----- Tetany due to low Ca level, aplasia or hypoplasia of teeth when the effect occur before the teeth were entirely formed, large pulp chamber, delayed resorption and eruption

The Adrenals

Paired organs situated near the upper surface of each kidney, consists of outer layer(cortex) and inner layer (Medulla)

Cushing’s Syndrome

Characterized by adrenocortical hyper-function, obesity in upper part of body, muscle weakness, there is premature epiphysis closure in children

Precocious Puberty

Occurs as a result of disturbance in hypothalamus, pituitary, adrenal, and Gonads, growth accelerated at first but followed by advanced epiphyseal closure

Cherubism

Symmetrical fibro-osseous lesions causing enlargement of the jaws. alveolar ridges are wide lead to narrow palate to V shaped, mal-alignment and malformation and irregularities of the teeth

Achondroplasia

The most common primary skeletal dysplasia. Disturbance in the endochondral bone formation which result the characteristic form of Dwarfism

Arthritis

Infectious, rheumatoid, degenerative and traumatic

Allergy

Children subjected to nasal allergy, bronchial asthma and allergic rhinitis often have nasal obstruction and mouth breathing which is common etiologic factor in development of malocclusion

Anemia

Chronic long standing anemia during childhood may result in dentofacial underdevelopment especially of persist during active growth periods

Amyloidosis

Serious conditions caused by a build-up of an abnormal protein called amyloid in organs and tissues

Hurler syndrome

Excessive intracellular accumulation of chondroitin sulfate and hepartine sulfate(carbohydrate metabolism)

Nutritional Deficiency

Strong predisposing factor in the dentofacial deformity, growth retardation is observed in children with chronic malnutrition

Finger Sucking

It is repeated forceful sucking of the thumb with associated strong buccal and lip contractions

Tongue Thrust

The tongue makes contact with any teeth anterior to the molars during swallowing

Mouth breathing

Habitual respiration through the mouth instead of the nose

Lip Sucking & Biting

Lip sucking may appear by itself or may be seen with thumb sucking, the lower lip is the most frequently involved and also the upper lip may be involved

Nail Biting

One of the most common habits in children and adults, it is a sign of internal tension

Pillowing habit

Postural defect during sleep are considered as an etiologic factor in the development of malocclusion

Traumatic Occlusion

Excessive force created by such habits like bruxism may be more than the physiologic limit of the periodontal fibers

Accident & Trauma

Accidents are more significant factor in malocclusion, as the child is learn to crawl and walk, the face and dental arches are receiving trauma

Chin Propping Habit

A chin propping habit cause a deep anterior closed bite, and may also cause the mandible to be retracted

Muscle Weakness

Found to be associated with underdevelopment of the mandible, strong muscle action is associated with strong well developed jaws but not necessarily always with good dental alignment