Comparing two quantitative methods for studying remineralization of artificial caries.

OBJECTIVES To compare the detection of changes before and after remineralization of artificial enamel and dentin caries by microCT scanning, polarized light microscopy (PLM) and transverse microradiography (TMR). METHODS Fourteen extracted premolars were cut into tooth blocks and painted with an acid-resistant varnish leaving one enamel and one dentin surface exposed. The tooth blocks were immersed into demineralizing solution for 4 days to produce artificial caries-like lesions and scanned by microCT. Then the 14 tooth blocks were randomly allocated into two groups. Seven tooth blocks in Group I were cut longitudinally through the exposed surface into 100-150 microm thick sections and microradiographs were taken. The other seven tooth blocks in Group II were left intact. All the tooth blocks and sections were then immersed into remineralizing solution for 5 days. PLM and TMR of the tooth sections in Group I were taken again. Depth of the lesion on the TMR was measured. Tooth blocks in Group II were scanned by microCT. RESULTS Mean lesion depth in Group I reduced by 13.0% and 8.2% after remineralization for enamel and dentin, respectively (paired t-test, P<0.001). In Group II, linear attenuation coefficient (LAC) of the region of interest (ROI) increased by 11.1% and 23.8% after remineralization for enamel and dentin lesions, respectively (paired t-test, P<0.001). CONCLUSION Both microCT and microradiography are able to detect a change of similar magnitude in the artificial caries lesions after remineralization. MicroCT may be used to substitute TMR and PLM in in vitro studies about caries.

[1]  J. Wefel,et al.  Comparisons of in vitro root caries models. , 1995, Caries research.

[2]  N. King,et al.  The Effect of Chewing Gums Containing Calcium Phosphates on the Remineralization of Artificial Caries-Like Lesions in situ , 2005, Caries Research.

[3]  S. Stock,et al.  X-ray absorption microtomography (microCT) and small beam diffraction mapping of sea urchin teeth. , 2002, Journal of structural biology.

[4]  D. Wood,et al.  Microcomputerised tomography evaluation of 10% carbamide peroxide applied to enamel. , 2005, Journal of dentistry.

[5]  G W Marshall,et al.  Three-dimensional mapping of mineral densities in carious dentin: theory and method. , 1994, Scanning microscopy.

[6]  F. Wong,et al.  X-ray microtomographic study of mineral concentration distribution in deciduous enamel. , 2004, Archives of oral biology.

[7]  Daniel Fried,et al.  Polarization-sensitive optical coherence tomographic imaging of artificial demineralization on exposed surfaces of tooth roots. , 2009, Dental materials : official publication of the Academy of Dental Materials.

[8]  S. Stock,et al.  Synchrotron microComputed Tomography of the mature bovine dentinoenamel junction. , 2008, Journal of structural biology.

[9]  K. Kunzelmann,et al.  Mineral concentration of natural human teeth by a commercial micro-CT. , 2006, Dental materials journal.

[10]  N. King,et al.  Effects of child formula dentifrices on artificial caries like lesions using in vitro pH-cycling: preliminary results. , 2007, International dental journal.

[11]  D. Pashley,et al.  The effect of fluoridated and non-fluoridated rewetting agents on in vitro recurrent caries. , 2001, Journal of dentistry.

[12]  F. Wong,et al.  Theoretical explanation of the relationship between backscattered electron and x-ray linear attenuation coefficients in calcified tissues. , 2006, Scanning.

[13]  Daniel Fried,et al.  Nondestructive assessment of dentin demineralization using polarization-sensitive optical coherence tomography after exposure to fluoride and laser irradiation. , 2009, Journal of biomedical materials research. Part B, Applied biomaterials.

[14]  D. Wood,et al.  Thirty-five percent carbamide peroxide application causes in vitro demineralization of enamel. , 2007, Dental materials : official publication of the Academy of Dental Materials.

[15]  F. Wong,et al.  X-ray microtomography of bones and teeth. , 1996, Physiological measurement.

[16]  N. King,et al.  In vitro model for evaluating the effect of child formula toothpastes on artificial caries in primary dentition enamel. , 2005, American journal of dentistry.

[17]  N. King,et al.  The effects of child formula toothpastes on enamel caries using two in vitro pH-cycling models. , 2005, International dental journal.

[18]  F. Wong,et al.  Determination of mineral concentration in dental enamel from X-ray attenuation measurements. , 1998, Connective tissue research.

[19]  P. Cloetens,et al.  Synchrotron X-Ray Microtomographic Investigation of Mineral Concentrations at Micrometre Scale in Sound and Carious Enamel , 2004, Caries Research.

[20]  J. T. ten Bosch,et al.  Invited Review: A Review of Quantitative Methods for Studies of Mineral Content of Intra-oral Incipient Caries Lesions , 1991 .

[21]  L. Qin,et al.  Low-dose X-irradiation promotes mineralization of fracture callus in a rat model , 2008, Archives of Orthopaedic and Trauma Surgery.

[22]  M. Hahn,et al.  High Spatial Resolution Imaging of Bone Mineral Using Computed Microtomography: Comparison with Microradiography and Undecalcified Histologic Sections , 1993, Investigative radiology.

[23]  S. Wei,et al.  Morphology of initial lesions of enamel treated with different commercial dentifrices using a pH cycling model: scanning electron microscopy observations. , 1999, International dental journal.

[24]  D. Fried,et al.  Nondestructive assessment of the inhibition of enamel demineralization by CO2 laser treatment using polarization sensitive optical coherence tomography. , 2008, Journal of biomedical optics.

[25]  G. Davis,et al.  Longitudinal Study of the Three-Dimensional Development of Subsurface Enamel Lesions during in vitro Demineralisation , 2003, Caries Research.