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Relation between incremental lines and tensile strength of coronal dentin
Toshiko Inoue1, Makoto Saito, Masato Yamamoto
1Division of Oral Biomaterials and Technology, Department of Conservative Dentistry, Showa University School of Dentistry, Tokyo, Japan. inoue@dent.showa-u.ac.jp
Dental Materials Journal
|August 7, 2012
Summary
Tensile strength in dentin is higher when force is applied parallel to incremental lines compared to perpendicular. This structural anisotropy effect was observed in both human molars and bovine incisors.
Area of Science:
- Biomaterials Science
- Dental Materials
- Biomechanics
Background:
- Coronal dentin's mechanical properties are crucial for tooth function and restoration longevity.
- Incremental lines in dentin represent daily growth layers, potentially influencing structural integrity.
- Understanding dentin's anisotropic behavior is essential for predicting its response to various loading conditions.
Purpose of the Study:
- To investigate the effect of incremental line orientation on the tensile strength of human molar and bovine incisor dentin.
- To determine if tensile loading parallel or perpendicular to incremental lines yields different strength values.
- To compare the anisotropy of dentin between human molars and bovine incisors.
Main Methods:
- Tensile strength testing was performed on four groups: human molar parallel (HPa), human molar perpendicular (HPe), bovine incisor parallel (BPa), and bovine incisor perpendicular (BPe) to incremental lines.
- Statistical analysis (p<0.05) was used to compare tensile strength between groups.
Main Results:
- Tensile strengths in the parallel groups (HPa, BPa) were significantly higher than in the perpendicular groups (HPe, BPe).
- This confirms that incremental lines contribute to structural anisotropy in coronal dentin.
- No significant difference in the magnitude of the anisotropy effect was found between human and bovine dentin.
Conclusions:
- Coronal dentin exhibits significant structural anisotropy due to incremental lines, affecting its tensile strength.
- Tensile loading parallel to incremental lines results in greater strength than perpendicular loading.
- The degree of anisotropy in tensile strength is comparable between human molar and bovine incisor dentin.
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