Aetiology of Malocclusion in Orthodontics

Malocclusion

Deviation from ideal occlusal relationship.

Aetiology

Study of causes or origins of conditions.

Skeletal Aetiology

Causes of malocclusion related to skeletal structure.

Dental Aetiology

Causes of malocclusion related to teeth.

Soft Tissue Aetiology

Causes of malocclusion related to soft tissues.

Genetic Factors

Inherited traits influencing malocclusion development.

Environmental Factors

External influences affecting occlusal abnormalities.

Combination Aetiology

Malocclusion caused by multiple factors.

Class I Skeletal Pattern

Normal anteroposterior relationship of jaws.

Class II Skeletal Pattern

Maxillary protrusion or mandibular retrusion.

Class III Skeletal Pattern

Maxillary retrusion or mandibular protrusion.

Vertical Skeletal Discrepancy

Variation in vertical jaw relationships.

Low Angle Skeletal Pattern

Characterized by a short face appearance.

High Angle Skeletal Pattern

Characterized by a long face appearance.

Transverse Skeletal Crossbites

Asymmetrical relationship of upper and lower jaws.

Anteroposterior Skeletal Discrepancy

Discrepancy in front-back jaw positioning.

Mild Asymmetries

Slight differences in facial structure.

Twin Studies

Research method for genetic influence analysis.

Mouth Breathing

Breathing through the mouth affecting dental health.

Syndromes

Genetic conditions influencing malocclusion.

Mandibular Condyle Fracture

Injury affecting jaw alignment and function.

Aetiology

Study of causes of dental conditions.

Malocclusion

Misalignment of teeth and jaws.

Multifactorial

Involving multiple factors or causes.

Supernumerary teeth

Extra teeth beyond the normal series.

Hypodontia

Developmental absence of one or more teeth.

Microdontia

Abnormally small teeth.

Macrodontia

Abnormally large teeth.

Transposition

Position exchange of two teeth.

Impaction

Tooth unable to erupt properly.

Ectopic position

Tooth located in an abnormal position.

Delayed eruption

Later than normal tooth emergence.

Early loss of teeth

Premature loss of primary or permanent teeth.

Late loss of teeth

Delayed loss of primary or permanent teeth.

Talon cusp

Abnormal cusp on the tooth surface.

Ankylosed tooth

Tooth fused to bone, preventing eruption.

Space maintenance

Preserving space for future tooth eruption.

Crowded arch

Insufficient space for teeth in the jaw.

Asymmetric retention

Unequal retention of teeth affecting alignment.

CL shifts

Changes in dental midline due to tooth loss.

Incidence of supernumerary teeth

4-6% prevalence excluding third molars.

Types of supernumeraries

Conical, tuberculate, supplemental, and odontomes.

Dental Aetiology

Study of dental disease causes and factors.

Microdontia

Variation in tooth size; prevalence 2.5%.

Macrodontia

Variation in tooth size; prevalence 1%.

Supernumerary Teeth

Extra teeth beyond the normal count.

Hypodontia

Congenital absence of one or more teeth.

Impaction

Tooth blocked from erupting by a barrier.

Transposition

Positional interchange of adjacent teeth.

Ectopic Position

Tooth erupts in an abnormal location.

Talon Cusp

Abnormal tooth form resembling a talon.

Delayed Eruption

Later than normal emergence of permanent teeth.

Early Loss of Deciduous Teeth

Premature loss of primary teeth.

Late Loss of Deciduous Teeth

Delayed loss of primary teeth.

Early Loss of Permanent Teeth

Premature loss of adult teeth.

Crowded Arch

Insufficient space for teeth in the dental arch.

Genetic Factors

Influence of genes on dental abnormalities.

Environmental Factors

Impact of external conditions on dental health.

MSX1 Gene

Gene linked to hypodontia and microdontia.

PAX9 Gene

Gene associated with tooth development issues.

Sonic Hedgehog Gene (Shh)

Initiates tooth formation; absence causes agenesis.

Ectopic Tooth

Tooth following an abnormal eruption path.

Prevalence of Maxillary Canines

Impaction occurs in 2-3% of cases.

Aetiology

Study of causes of malocclusion.

Multifactorial

Involves multiple contributing factors.

Soft tissue aetiology

Influence of soft tissues on dental alignment.

Equilibrium theory

Teeth position stabilizes with surrounding tissues.

Pressure from the tongue

Tongue forces affect tooth positioning.

Pressure from the lips

Lip forces influence dental alignment.

Pressure from the cheeks

Cheek forces impact tooth positioning.

Lip competence

Ability of lips to maintain closure.

Lower lip position

Position affects upper incisors' retroclination.

Incompetent lips

Inability to maintain lip closure, causing issues.

Lower lip trap

Condition exacerbating increased overjet.

Adaptive tongue thrust

Tongue thrusting due to malocclusion.

Endogenous tongue thrust

Primary cause of malocclusion from tongue posture.

Non-nutritive sucking habits

Sucking behaviors affecting dental alignment.

Thumb sucking

Type of non-nutritive sucking habit.

Dummy sucking

Sucking on pacifiers; impacts dental structure.

Maxillary arch length

Length of upper dental arch; can increase.

Mandibular arch width

Width of lower dental arch; can widen.

Labial frenum

Tissue connecting lip to gums; affects spacing.

Low frenal attachment

Frenum attachment causing potential midline diastema.