Evaluation of in vitro secondary caries using confocal laser scanning microscope and X-ray analytical microscope.
OBJECTIVE
To evaluate in vitro secondary caries formation and inhibition by using a confocal laser scanning microscope (CLSM), and further map the calcium distribution with an X-ray analytical microscope (XAM).


METHODS
36 box-shaped cavities were prepared on bovine root dentin and restored with Fuji II, Fuji II LC (improved), or Clearfil Liner Bond 2V system with a non-fluoride releasing resin-based composite; Clearfil AP-X was used as a negative control. After immersion in a buffered demineralizing solution of 50 mmol/L of acetic acid adjusted to pH 4.5 for 3.5 days, longitudinal half sections were cut through each restoration and polished for analysis under CLSM. In order to confirm the CLSM results, the same samples were subsequently examined by means of the X-ray analytical microscope (XAM). The values of the outer lesions and the inhibition zones obtained by the two different CLSM and XAM measurements were then analyzed by one-way ANOVA, Fisher's PLSD Test at the 95% level of confidence and correlation coefficient.


RESULTS
Inhibition zones and outer lesions were clearly detected under CLSM around the glass-ionomer and resin-modified glass-ionomer restorations. As expected, an inhibition zone was not detected adjacent to the resin-based composite restoration. Additionally, using the transmission x-ray images of XAM, the inhibition zones were observed as high density areas, and the outer lesions as low density areas. The width of the inhibition zones and the depth of the outer lesions measured under the CLSM were similar to those obtained from the XAM.
Okuda
Mamiko
M
Cariology and Operative Dentistry, Department of Restorative Sciences, Graduate School, Tokyo Medical and Dental University, 5-45 Yushima 1-chome, Bunkyo-ku, Tokyo 113-8549, Japan.
Pereira
Patricia N R
PN
Nikaido
Toru
T
Tagami
Junji
J
D000085:Acetates / Q000737:chemistry; D000704:Analysis of Variance; D000818:Animals; D002118:Calcium / Q000032:analysis; D002417:Cattle; D016001:Confidence Intervals; D003731:Dental Caries / Q000473:pathology*; D003793:Dental Restoration, Permanent; D003804:Dentin / Q000473:pathology; D017220:Dentin-Bonding Agents / Q000737:chemistry; D004577:Electron Probe Microanalysis; D005899:Glass Ionomer Cements / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D008689:Methacrylates / Q000737:chemistry; D018613:Microscopy, Confocal; D012008:Recurrence; D019279:Resin Cements / Q000737:chemistry; D012117:Resins, Synthetic / Q000737:chemistry; D013499:Surface Properties; D017001:Tooth Demineralization / Q000473:pathology; D014092:Tooth Root / Q000473:pathology
D000085:Acetates; C112828:Clearfil AP-X; C112274:Clearfil Liner Bond 2; D017220:Dentin-Bonding Agents; C079765:Fuji II LC cement; D005899:Glass Ionomer Cements; D008689:Methacrylates; D019279:Resin Cements; D012117:Resins, Synthetic; C084541:Fuji glass-ionomer lining cement; D002118:Calcium