抄録
Introduction:
The occurrence and progression of a caries lesion are associated with an imbalance or equilibrium of de- and remineralization. The progressing pattern of caries is observed not only in the subsurface lesion but also in surface-softened lesion. The progression of caries in the grooves also might depend on the pH changes inside of the grooves. The aim of this study is to analyze of the demineralization pattern in the different grooves using New software as a convenient analysis method for dental microradiography.
Materials and Methods:
A 100µm thickness single-section specimen was prepared from human extracted molar. All of surfaces of the specimen, except for the area studied, were coated with Sticky Wax. Two different grooves with 200µm (N group: n=6) or 400µm (W group: n=6) width accompanying 1-mm depth were prepared in the human molar. The coated surface of specimen was covered with Para film and these specimens were immersed into the fluid with automatic-pH-cycling system.
The system was carried out at 9 cycles /day during 2 or 4 weeks, in which the pH value was kept for 37 min under 5.5 at one cycle. The Transverse microradiography images (TMR images) were taken before and after the procedure of pH-cycling.
The parameters such as mineral loss (∆Z), lesion depth (Ld), surface zone depth (SZd), and lesion body depth (LBd) of tooth specimens and additionally the outer surface zone (OSZ), inner lesion body (ILB), and sandwich area (SA) between OSZ and ILB — which together constituted ∆Z – of the dentin at enamel-dentin junction were calculated by the newly developed program (Fig.1).
Results:
The subsurface lesions were observed in the group W at any weeks. whereas those were found in the group N only at week 4. ∆Z and SA were significantly higher in the group W than in the group N at any weeks. (Paired t test, p<0.05).
Disccusion:
These results indicate that not only the demineralization volume but also the demineralization pattern of dentin are depending on the width of grooves artificially made.
Conclusion:
The caries lesion will start the surface-soften lesion and subsequently progress into the subsurface lesion
