Before dental treatment requiring neck extension for a patient with Down syndrome, the clinician should be aware of the risk of:

Up to about 15% of individuals with Down syndrome have atlantoaxial instability (ligamentous laxity at C1-C2). Excessive neck extension or manipulation can compress the spinal cord, so avoid extreme head and neck positioning and keep appointments short.Other options: Down syndrome is associated with periodontal disease (not caries immunity); salivary flow and LA response are not the key positioning concern.Key exam takeaway: Down syndrome carries atlantoaxial instability risk; avoid extreme neck extension/manipulation to prevent cord injury.