Correspondence

A Fragile Balance

N Engl J Med 2009; 361:1611October 15, 2009

Article

To the Editor:

In their description of a patient with osteogenesis imperfecta, Bitton et al. (July 2 issue)1 allude to the patient's remark that his dentist noted “thin tooth enamel,” although on clinical examination the “teeth appeared normal.” During enamel formation, there is production of matrix protein that mineralizes, but no collagen is involved. The dentin of the tooth crown and the bulk of the tooth roots are similar in composition to bone, although they are different in structure, and collagen matrix is mineralized in dentin formation. The changes observed on dental radiography in many cases of osteogenesis imperfecta are pathognomonic in the clinical setting of osteopenia and multiple fractures; these changes include abnormality in the size of the pulp chambers of the teeth and markedly thin dentin, with thin roots of the teeth.

Better communication with the patient's dentist early on might have strongly pointed to the diagnosis. If the patient's dentist were unavailable, a dental consultation and an inexpensive set of radiographs might have contributed much to the diagnosis at relatively little expense.

George T. Gallagher, D.M.D., D.M.Sc.
Boston University Henry M. Goldman School of Dental, Medicine, Boston, MA
ggalla@bu.edu

1 References

1. 1

   Bitton A, Yialamas M, Levy BD, Katz JT, Loscalzo J. A fragile balance. N Engl J Med 2009;361:74-79
   Full Text | Web of Science | Medline

Author/Editor Response

We thank Gallagher for pointing out that osteogenesis imperfecta can be diagnosed, in part, on the basis of findings on dental radiography if clinical suspicion is high. In this case, physicians looking for evidence of external dental manifestations of osteogenesis imperfecta were unduly swayed against the diagnosis by the absence of physical signs of dentinogenesis imperfecta. Dentinogenesis imperfecta is a hereditary disorder of dentin formation with three main types, of which only type I is associated with osteogenesis imperfecta.1,2 Dentinogenesis imperfecta is characterized by opalescent teeth with brown or gray discoloration and radiographic abnormalities such as pulp stones and short roots; this disorder affects the primary teeth more than the permanent teeth.2 Although the enamel is structurally normal, it may shear more frequently from the underlying abnormal dentin.3 Dentinogenesis imperfecta has been detected by physical examination alone in approximately 19% of patients with osteogenesis imperfecta, but it has been detected by clinical examination and radiography together in 70% of patients with osteogenesis imperfecta.4 We certainly agree that better communication and coordination of care between dentists and physicians can facilitate improvements in the diagnosis of systemic conditions such as osteogenesis imperfecta.

Asaf Bitton, M.D.
Joel T. Katz, M.D.
Joseph Loscalzo, M.D., Ph.D.
Brigham and Women's Hospital, Boston, MA
jkatz@partners.org

4 References

1. 1

   Teixeira CS, Santos Felippe MC, Tadeu Felippe W, Silva-Sousa YT, Sousa-Neto MD. The role of dentists in diagnosing osteogenesis imperfecta in patients with dentinogenesis imperfecta. J Am Dent Assoc 2008;139:906-914
   Web of Science | Medline

2. 2

   Kim JW, Simmer JP. Hereditary dentin defects. J Dent Res 2007;86:392-399
   CrossRef | Web of Science | Medline

3. 3

   Lindau BM, Dietz W, Hoyer I, Lundgren T, Storhaug K, Noren JG. Morphology of dental enamel and dentine-enamel junction in osteogenesis imperfecta. Int J Paediatr Dent 1999;9:13-21
   CrossRef | Medline

4. 4

   Saeves R, Lande Wekre L, Ambjornsen E, Axelsson S, Nordgarden H, Storhaug K. Oral findings in adults with osteogenesis imperfecta. Spec Care Dentist 2009;29:102-108
   CrossRef | Medline