I just found a newly released article in the Journal of Dental Research that links dental problems associated with cleft lip and palate to abnormalities in salivary glands and an imbalance of immune compounds in the mouth.
Dr. Cox and his team knocked out this major gene in a group of mice during late embryonic development in the oral epithelium (the outermost layer of tissue in the mouth). Mice with this Irf6 knockout had poorly formed salivary glands, leading to reduction in salivary flow rate and buffering capability, while significantly increasing the acidity of the oral environment. Also, Irf6 knockout mice had reduced expression of a major immune cytokine in their mucosal and skin tissues, leading to increased oral bacterial colonization. Increased bacterial colonization, along with a highly acidic environment in the mouth, combine to cause dental caries. Mice with this knockout condition displayed increased susceptibility to dental caries as a result of the salivary gland abnormalities, leading to high acidity and increased bacterial content in their mouths that worked to erode their teeth. A high sugar diet made this problem even worse. From this work, Dr. Cox concluded that individuals with cleft lip and palate are more susceptible to dental caries due to genetically linked salivary gland malformations that compromise salivary function and immune response against oral bacteria, leading to the high acidity and bacterial content that are involved in dental decay. Due to their susceptibility to dental caries, the oral and dental health of people with cleft lip and palate should be closely monitored and preventative measures taken early on in life to reduce this risk.