Comparison of the number and diameter of dentinal tubules in human and bovine dentine by scanning electron microscopic investigation

Detailed information on dentine structure is essential for interpreting dat a from investigations on dentine-adhesive materials. The purpose here was t o compare the number and diameter of dentinal tubules at similarly prepared surfaces of bovine permanent central incisors and human deciduous and thir d molars. In bovine teeth, crowns and roots were used. in human samples onl y the crowns were investigated. Tubule density in the middle layer was high er in bovine root (BR) dentine (number of tubules per mm(2) +/- SD: 23,760 +/- 2453) than in human deciduous (HD) (18,243 +/- 3845), human permanent ( HP) (18,781 +/- 5855), and bovine coronal (BC) (17,310 +/- 2140) dentine. T he corresponding values for the deep layer were 23,738 +/- 4457 (BR), 24,16 2 +/- 5338 (HD), 21,343 +/- 7290 (HP), and 20:980 +/- 4198 (BC). No signifi cant differences were found for the number of dentinal tubules in bovine co ronal dentine compared to the dentine of human deciduous and permanent mola rs. The mean diameter of bovine dentinal tubules was slightly, but not sign ificantly, higher than in human dentine (middle layer/deep layer +/- SD): B C, 2.85 eta m +/- 0.18/3.50 mu m +/- 0.33; BR, 3.10 mu m +/- 0.33/3.23 mu m +/- 0.30; HD, 2.55 mu m +/- 0.16/2.82 mu m +/- 0.28; HP, 2.65 mu m +/- 0.1 9/ 2.90 mu m +/- 0.22. These findings demonstrate that corresponding corona l dentine layers of human deciduous and permanent molars, and of bovine cen tral incisors, are not significantly different in their number of tubules p er mm(2) and their tubule diameter, whereas tubule density in bovine root d entine is significantly higher. These results suggest that provided standar dized preparations are used, bovine incisor crown dentine is a suitable sub stitute for human molar dentine in adhesion studies. (C) 2000 Elsevier Scie nce Ltd. All rights reserved.