Evaluation of Caries-Affected Primary-Teeth Restored with Crowns Cemented with GIC

Objective: To characterize the chemical nature and chemical changes over time of dentin and enamel of primary teeth after restoring with stainless steel crowns cemented with glass ionomer cement (GIC) under µRaman spectroscopy and the visual characteristics under atomic force microscope (AFM)

Method: 15 caries affected primary teeth were prepared and restored with stainless steel crowns and cemented GIC. The specimens were stored in Hank's solution at 37 ºC and randomly divided in 3 storage groups for 24 hours, 3 months and 6 months. After the respective storing times the chemical nature and changes of dentin and enamel substrates were determined in the specimens  by evaluating the spatial variations of inorganic and organic contents using Raman microspectroscopy. Specimens were evaluated under AFM.

Result: Specimens stored for 3 and 6 months showed a phosphate ν1 band located around 962.0 cm^-1. Dentin primary specimens showed major peaks associated with the organic component appear at 1242 cm^-1 and at 1667 cm^-1 Other peak assignments in this region include the peaks at 1072 cm^-1 (1 symmetric stretch, (CO₃ )^2-, and 1452 cm^-1. In general, all the peaks showed higher intensity in the 3 months and 6 months groups compared to the 24 hours group. Furthermore a shift of the v1 band to higher wave numbers was observed indicating the formation of fluorapatite (FAP) after 3 and 6 months. AFM confirmed the presence of caries affected enamel and dentin with morphological differences on all the specimens after 3 months and 6 months of storage.

Conclusion: These study showed the formation of FAP after restoring the caries affected primary teeth with GIC and store them for 3 and 6 months and there was indication of micro structural changes in enamel and dentin by AFM analysis.

Acknowledgements: NIH/NIDCR/K23DE-020091-02, UCSF/SOS/CTSI/RAP award