Dentinogenesis imperfecta: evidence of qualitative alteration in the organic dentin matrix

Deciduous teeth affected by dentinogenesis imperfecta were obtained from two patients with osteogenesis imperfecta. Electronmicroscopy of the dentin revealed some structural alterations. The striation of the collagen fibrils was not clear, and the crystals were less dense than in normal dentin. The amino acid analysis of dentin collagen was slightly different from normal dentin. There were slight increases in the amounts of hydroxylysine, serine and acidic acids. On the other hand, lysine and arginine were reduced. The elevation of hexosyllysine content and an increase of carbohydrate were also observed. These results indicate that either dentin collagen is altered, or noncollagenous matrices associated with collagen are increased in dentinogenesis imperfecta dentin.