IADR Abstract Archives
Dentin tubule numerical density variations below CEJ
Objectives: Dentin structure and tubule numerical density shows marked variation in the crown, but little information is available on mean numerical of tubule density below the CEJ. We evaluated this variation.
Materials and Methods: Human non-carious permanent canines were sectioned parallel to the CEJ to obtain a dentin disk of 1mm thickness whose surfaces were 1 mm and 2 mm below the CEJ. The disc was sectioned into quarters resulting in four segment locations (L= buccal, lingual, mesial, and distal.) The outer (PDL side) and Inner (pulp side) surfaces of the specimens were shaped to expose dentin with SiC papers and polished through 0.25 μm diamond suspension. SEM images were collected for measurement of tubule numerical density for each tooth at 12 locations per specimen (i.e. outer/inner, left/center/right, H= 1mm/2mm) and analyzed with image analysis software. All data were statistically analyzed using a three-way ANOVA.
Results: The dentin tubule/mm2 are summarized in the table. (Mean (S.D.)) There was a significant difference between inner and outer surfaces. (P<0.0001). The other variables were not significantly different (P = 0.08 for L; P = 0.10 for H). Tubule density increased by a factor of about two from outer to the inner surface.
|
|
|
Buccal |
Lingual |
Mesial |
Distal |
|
Outer |
1 mm |
16300(1300) |
16800(2200) |
13700(1800) |
15000(1700) |
|
|
2 mm |
15200(1400) |
14700(1500) |
16500(2600) |
16200(3500) |
|
Inner |
1 mm |
31400(5100) |
28400(2800) |
25300(2900) |
28700(4200) |
|
|
2 mm |
32300(2600) |
31600(4400) |
26000(3400) |
29100(4700) |
Conclusion: Dentin tubule density was relatively uniform at 1 and 2 mm below the CEJ and increased from outer to inner surface by a factor of two. This study suggests the dentin substrate in the root may not present the marked changes in tubule density variations typical of coronal dentin with location and this may have implications for adhesives for root caries prevention/treatment, hypersensitivity treatment, and endodontics.
Acknowledgement: NIH/NIDCR P01DE09859