ESPE Abstracts

Background: Osteogenesis imperfecta (OI) is characterized by abnormal bone development with low bone mass and increased bone fragility. Dominant mutations affect synthesis & structure of type 1pro-collagen. Recessive mutations affect post-translational processing or tracking of type 1 pro-collagen. OI may be associated with dentinogenesis imperfecta type 1, for both primary and permanent dentition, particularly primary, manifested as tooth discoloration, reduced enamel thickness in some, with vertical enamel fracture, associated short roots and bulbous crowns. Bisphosphonates, acting primarily as osteoclast inhibitors, have been used for over 20 years to increase bone hardness and reduce fracture risk in OI. The drug is taken up rapidly into bone and bound to the crystal structure. Bisphosphonates are reported to disrupt odontoblast(dentine formation) and ameloblast (enamel formation) activity in an animal model. There are no similar reports in humans.

Objective and hypotheses: To report dental appearance and progress of 3 children with severe OI (Sillence type 3 (progressively deforming OI with normal sclerae) treated with IV bisphosphonate from the first postnatal week

Method: Each child received intravenous zoledronic acid infusions 4 monthly, from week 1, due to multiple pre and early postnatal long bone fractures. Infusions were administered for >8 years, with increasing intervals between treatment cycles based on improving bone mineral density.

Results: Primary dentition demonstrated abnormal teeth in all, with brown discolouration of all teeth, increased wear, progressive loss of dental height and increased rate of tooth loss. Secondary dentition by contrast revealed almost white teeth with normal colour and appearance and no signs of reduced enamel or dentine.

Conclusion: Very early treatment of dentinogenesis imperfecta associated with OI can result in improved dental health. For dosages used in children it does not have any adverse effect on clinical outcome and may enhance tooth quality, compared to primary dentition.