The Etiology of Orthodontic Problems：正畸问题的病因.ppt

The Etiology of Orthodontic Problems Prepared by Dr Hana Omar Al Balbeesi Malocclusion and Dentofacial deformities result not only from some pathological processes, but also by moderate distortions of normal development. Causes of Orthodontic ProblemsEither from  Environmental influences Eg. Mandibular deficiency secondary to jaw fracture during childhood Or Genetic influences accompanied some rare genetic syndromes. However Orthodontic problems seem to arise from environmental and hereditary influences interaction. Etiologic Factors for malocclusion are Specific causes of malocclusion. Hereditary influences. Environmental influences. Specific causes of malocclusion:- Disturbances in Embryologic Development. Skeletal Growth Disturbances . Disturbances of Dental Development . Disturbances in Embryologic Development Drugs are either teratogenic or non teratogenic. Teratogenic drugs can cause specific defects with low doses ,or death in high doses. This table lists the teratogens known to produce orthodontic problems Skeletal Growth Disturbances Fetal Molding Birth Injures. Childhood fractures of the jaws. Muscle dysfunction. Acromegaly and Hemi mandibular Hyper trophy. 1.Fetal Molding and Birth injures : Injures at birth have two major categories: Intra uterine molding. Trauma to the mandible during birth from the forceps that used in delivery. A. Intra uterine Molding : Any pressure against the developing face lead to distortion of rapidly growing areas. Its not a true birth injury such as maxillary defeciency due to arm pressure flexing of head against chest leading to abnormal mandibular growth (Pierre Robin Syndrome) accompanied with cleft palate . If cartilage formation defect is present with (PRS) this will be called Stickler Syndrome . Child can recover if the source is stopped ,so early treatment should be avoided. Some others need surgical interference to catch