Demand for nutrients necessary for the formation of mineralized tissues increases dramatically during pregnancy to meet fetal requirements. The purpose of this clinical study was to identify short-term effects of pregnancy and dietary intakes of calcium, phosphorus, protein, and vitamin C on radiographic density and alveolar crest morphology of the mandible.

Seventy-six subjects between ten and 20 weeks' gestational age were recruited from the Jefferson County, Alabama, Department of Health maternity clinic. Initially, an evaluation of their diet was done, and a single periapical radiograph was taken in the canine-premolar region of the mandible. A final evaluation of the diet and a periapical radiograph of the same teeth were obtained at a time as close to the expected date of delivery as possible.

Dietary evaluation consisted of a 24-hour recall history and a food-frequency history at the two visits. Radiographs were made with a bite-block film-holding system with occlusal registration in acrylic for reproduction of projection geometry at the two visits. An aluminum stepwedge was incorporated for densitometric standardization. Measurements of plaque, and bleeding and pocket-depth probing were recorded for control of local effects on alveolar change.

Standard statistical procedures of regression determined correlation of 12 nutrients and periodontal variables with bone density change and with alveolar crest morphology change. Vitamin C intakes (24-hour recall) showed a positive correlation (p = 0.033) with bone density change, and calcium intakes (24-hour recall) showed a negative, but not significant, correlation (p = 0.058) with bone density change, contributed particularly by subjects with the highest calcium intakes. The strongest relation with alveolar crest morphology change was the interproximal pocket-depth change (p = 0.086).