1272 Novel Link Between Xerostomia and Tooth Decay in Diabetic Model

Saturday, March 24, 2012: 9:45 a.m. - 11 a.m.
Presentation Type: Poster Session
D. LARIVEY1, C. YEH2, D. HORN3, Y.P.P. CHUN4, J. JORGENSEN3, M. MACDOUGALL5, and S. ABBOUD-WERNER6, 1Dental School, University of Texas - San Antonio / Health Science Ctr, San Antonio, TX, 2Comprehensive dentistry, University of Texas - San Antonio / Health Science Ctr, San Antonio, TX, 3Pathology, University of Texas - San Antonio / Health Science Ctr, San Antonio, TX, 4Periodontics, University of Texas at San Antonio, San Antonio, TX, 5James Rosen Chair in Dental Research, University of Alabama at Birmingham, Birmingham, AL, 6Pathology, University of Texas at San Antonio, San Antonio, TX

Insulin-dependent type-1 diabetes mellitus (DM) and oral diseases are closely interrelated. Poor metabolic control in diabetics is associated with a high risk of gingivitis, periodontitis and tooth loss. Salivary flow declines in diabetics and patients suffer from xerostomia. Reduced saliva predisposes to enamel hypomineralization and caries formation; however, the mechanisms that initiate and lead to progression of tooth decay and periodontitis in type-1 DM have not been explored. To address this issue, we analyzed tooth morphology in Akita-/- mice that harbor a point mutation in the Ins2 insulin gene which leads to insulin deficiency and hyperglycemia. Objective: To characterize the tooth phenotype in Akita-/- mice and determine whether hyperglycemia and hyposalivation contribute to dental defects. Methods: Mandibles from Akita-/- and wild type littermates were analyzed by microCT, scanning EM and histology; teeth were examined for amelogenin and ameloblastin expression. Mice were injected with pilocarpine to assess saliva production. The effect of high glucose on cultured MD10-F2 pulp cells was also analyzed. Results: Akita-/-mice at 6 weeks showed chalky white incisors that correlated with marked hyperglycemia and impaired saliva production. MicroCT of Akita-/- teeth revealed excessive enamel wearing and hypomineralization; immunostaining for amelogenin and ameloblastin was decreased. A striking feature was invasion of dentinal tubules with Streptococcus mitis and microabcesses that originated in pulp horns and progressed to pulp necrosis and periodontitis. Akita+/-mice also developed dental defects. High glucose levels inhibited MD10-F2 cell proliferation/differentiation. Conclusions: Results provide the first evidence that hyperglycemia in combination with reduced saliva in a model of type-1-DM leads to decreased enamel mineralization/matrix proteins and predisposes to excessive wearing and decay. Importantly, hyperglycemia adversely affects enamel matrix proteins and pulp repair. Early detection and treatment of hyperglycemia and hyposalivation may provide a useful strategy for preventing dental complications of diabetes and promoting oral health in this population.  


This abstract is based on research that was funded entirely or partially by an outside source: NIH/NIDCR

Keywords: Caries, Caries organisms, Diabetes, Pulpal disease and Saliva