Dental Health and Prenatal Environment

Etiology of Malocclusion

• Heavy fibrous frenum may contribute to malocclusion
• Blanching of tissue lingual to maxillary central incisors can be noted

Prenatal Factors

• Trauma, maternal diet, and maternal metabolism can contribute to malocclusion
• Genetic factors can occur before birth
• Differentiative and congenital factors can also contribute to malocclusion
• Teratogens, such as chemicals and other agents, can produce embryonic defects if given at a critical time

Teratogens Affecting Dentofacial Development

• Aspirin, cigarette smoke, Dilantin, and Valium can cause cleft lip and palate
• Thalidomide can cause malformations, similar to hemifacial microsomia and Treacher Collins syndrome
• Infectious diseases, such as poliomyelitis, can contribute to malocclusion
• Vitamin D excess can cause premature suture loss
• Rubella virus can cause microphthalmia, cataracts, and deafness
• X-radiation can cause microcephaly

Postnatal Factors

• Developmental factors, such as functional and environmental interferences, can contribute to malocclusion
• Functional factors, such as muscular forces, can contribute to malocclusion
• Environmental factors, such as birth injury, delivery-induced deformation, and disabling accidents, can contribute to malocclusion
• Prolonged retention of deciduous teeth can cause malocclusion
• Premature loss of permanent teeth can also contribute to malocclusion

Leeway Space

• Maxillary leeway space is approximately 0.9 mm
• Mandibular leeway space is approximately 1.7 mm

Eruption of Permanent Teeth

• Permanent molar is likely to drift mesially more rapidly in the absence of occlusal contacts
• Maxillary canine often shows an abnormal eruptive pathway
• Sequence of eruption is affected by the distance it has to travel from its developmental position