Tooth eruption order is regular in most of children but not following the normal growth of the teeth should not always be considered abnormal. Exfoliation of deciduous teeth and eruption of permanent teeth are an important stage for child’s parent and dentist. Exfoliation of teeth is dental evolutionary movement in the axial direction from its formation origin in the bone until initiating its activity in the mouth. Attention to the findings of the physical examination, the presence or absence of developmental disorders, hydrocephalus, rickets, and cleft lip and palate, and anomalies, can indicate the presence of underlying genetic diseases or endocrine disorders. In other words, teething is a component of body growth and development which is influenced by various factors, serum levels of calcium and vitamin D, and underlying diseases. Careful attention of dentists to the various signs of eye, face, skeletal, cardiac and growth disorders in children and counseling, if needed, can help them in early detection of underlying disorders. Knowing the eruption time of permanent teeth helps the dentist to identify accelerated or delayed eruption of the teeth and evaluating its causes.