Altering calcium and phosphorus levels in utero affects adult mouse mandibular morphology

The purpose of our study was to determine morphological changes and bone mineral density (BMD) differences in the adult mandible of offspring exposed to high calcium, low phosphorus diets in utero until weaning age.

Time-mated FVB wild-type mice were fed normal or experimental diet during gestation and until weaning of offspring. Experimental diet contained 3-fold increase in calcium and 3-fold decrease in phosphorus compared to normal diet. Adult mandibles of offspring exposed to experimental diet were sacrificed and heads scanned using micro-computed tomography. Three-dimensional 3D geometric morphometric analysis GMA was utilized to detect morphological changes to the mandible including the condyle.

Experimental females showed the greatest morphological differences including shortened mandibular ramus width and height, shortened mandibular body length and height, a wider but shortened condylar neck and a wider condylar head in the lateral-medial direction. Experimental male mandibles trended towards increased mandibular body height and length, opposite the changes observed in experimental female mandibles, whereas condyles were similar to that observed in experimental females. Bone mineral density (BMD) was lowered in experimental females.

Increased calcium and decreased phosphorus levels led to a retrognathic mandible associated with lowered BMD in experimental females, whereas experimental showed partly opposite effects. Further studies are required to understand the mechanism underlying diet- and gender-specific differences in mandibular morphology.