These factors act additively or independently, ultimately affecting positioning and physical development of the tooth.Invasive environmental factors potentially affect tooth development and positioning leading to hypodontia and impaction. Examples include jaw fractures, surgical procedures and extraction of the preceding deciduous tooth. Treatment such as irradiation has been shown to have severe effects on developing teeth. In a smaller capacity, chemotherapy was also found to have a similar effect. Thalidomide (N-phthaloylglutamine) was also discovered to have a causative effect on mothers who took the drug during pregnancy, resulting in congenitally missing teeth in their children. A link was found between systemic diseases, endocrine disruption (i.e. idiopathic hypoparathyroidism and pseudohypoparathyroidism) and ectodermal dysplasia. However, a definite etiological relationship has yet to be established. Examples of infections include rubella and candida. Exposure to PCBs (such as dioxin), allergies, and toxic epidermal necrolysis folloeing a drug reaction may also be contributing factors. In a recent study assessing environmental risk factors for hypodontia, it was established that maternal smoking does play a causative role in hypodontia. Passive smoking and caffeine were also assessed but showed no statistical significance.The Journal of the American Dental Association published preliminary data suggesting a statistical association between hypodontia of the permanent teeth and epithelial ovarian cancer (EOC). The study shows that women with EOC are 8.1 times more likely to have hypodontia than are women without EOC. The suggestion therefore is that hypodontia can serve as a "marker" for potential risk of EOC in women.
Treatment
Instead of referring to "fetal distress", current recommendations hold to look for more specific signs and symptoms, assess them, and take the appropriate steps to remedy the situation through the implementation of intrauterine resuscitation. Traditionally the diagnosis of "fetal distress" led the obstetrician to recommend rapid delivery by instrumental delivery or by caesarean section if vaginal delivery is not advised.An algorithm is used to treat/resuscitate babies in need of respiratory support post-birth. The algorithm steps include: clearing the airways and warming, stimulating, and drying the baby, positive-pressure ventilation (PPV), supplementary oxygen, intubation, chest compressions, and pharmacological therapy. The order of these interventions is set, and each step is done for 30 seconds with heart rate monitoring and assessment of chest movement prior to escalating to the next step in the algorithm. References


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