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Comparisons between bone and cementum compositions and the possible basis for their layered appearances
S M Cool1, M R Forwood, P Campbell
1School of Biomedical Sciences, Department of Anatomy and Developmental Biology, University of Queensland, Brisbane, Queensland, Australia. s.cool@mailbox.uq.edu.au
Bone
|February 22, 2002
Summary
Human cementum layers, crucial for age estimation, are caused by mineral crystal orientation and size, not collagen changes. This finding clarifies the microstructure of dental cementum in forensic science.
Area of Science:
- Forensic Anthropology
- Dental Histology
- Biomineralization
Background:
- Age estimation from the adult skeleton relies on growth and maturational events.
- Human teeth exhibit appositional growth layers in midroot cementum, relevant for age determination.
Purpose of the Study:
- To investigate the underlying cause of the layered microstructure in human midroot cementum.
- To determine if layers result from mineralization, collagen changes, or organic matrix variations.
Main Methods:
- Analysis of human canine teeth midroot sections using polarized light microscopy and scanning electron microscopy (SEM).
- Examination of mineralized and demineralized sections, including decollagenized samples.
- SEM analysis included electron backscatter and electron probe for elemental composition and atomic number density.
Main Results:
- Polarized light microscopy indicated mineral phase, not collagen orientation, is responsible for cementum birefringence.
- SEM confirmed no significant changes in collagen packing or orientation across cementum width.
- SEM analysis revealed no variations in mean atomic number density, calcium, phosphate, or sulfur levels.
Conclusions:
- The layered appearance of human midroot cementum is primarily attributed to the crystalline orientation and/or size of its mineral component.
- Collagenous matrix and organic components do not appear to be the primary drivers of cementum layering.