Aetiology of malocclusion local factors 1 November 2016

Aetiology of malocclusion local factors (1) November 2016 Dr Mariam Al-Abdallah BDS, MSc (Eng), M-Orth (Edin), Ph. D (Eng) m. alabdallah@ju. edu. jo

References � Chapter 5 from (Contemporary Orthodontics) Proffit 4 th edition � Chapter 3 from (An Introduction to Orthodontics) by Laura Mitchell 3 rd edition.

Lecture Aims � Reinforce the multifactorial aetiology of malocclusion � Definition � Describe of local factors the role of local factors in the aetiology of malocclusion.

Malocclusion and dentofacial deformity Malocclusion is a developmental condition. � Malocclusion and dentofacial deformity are caused not by pathologic process, but by moderate distortions of normal development. � Occasionally single specific cause. e. g. genetic syndromes, fracture of the jaw More often complex interaction among multiple factors that influence growth and development.

about one third of the U. S. population has normal occlusion two thirds have some degree of malocclusion. in the malocclusion group, a small minority have problems attributable in a specific known cause; the remainder are the result of a complex and poorly-understood combination of inherited and environmental influences

Classification of local factors 1. Variation in tooth number 2. Variation in tooth form 3. Abnormalities in tooth position & eruption 4. Local abnormalities of soft tissues 5. Local pathology

1. Variation in tooth number �Supernumerary �Hypodontia �Premature loss of deciduous teeth �Unplanned loss of permanent teeth �Retained deciduous teeth

Tuberculate supernumerary

Supplemental supernumerary

Odontomes

Tooth agenesis (Hypodontia)

Premature loss of deciduous teeth