Odontoblast apoptosis and intratubular mineralization of sclerotic dentin with aging

Weishi Yan; Edwin Jiang; Cameron Renteria; Avina Paranjpe; Dwayne D Arola; Lan Liao; Xiuyun Ren; Hai Zhang

doi:10.1016/j.archoralbio.2022.105371

Odontoblast apoptosis and intratubular mineralization of sclerotic dentin with aging

Arch Oral Biol. 2022 Apr:136:105371. doi: 10.1016/j.archoralbio.2022.105371. Epub 2022 Feb 8.

Authors

Weishi Yan¹, Edwin Jiang², Cameron Renteria³, Avina Paranjpe⁴, Dwayne D Arola⁵, Lan Liao⁶, Xiuyun Ren⁷, Hai Zhang⁸

Affiliations

¹ Department of Materials Science and Engineering, University of Washington, Seattle, WA, USA. Electronic address: yanweishi.roman@gmail.com.
² Department of Materials Science and Engineering, University of Washington, Seattle, WA, USA. Electronic address: edwinj5@uw.edu.
³ Department of Materials Science and Engineering, University of Washington, Seattle, WA, USA. Electronic address: crenb@uw.edu.
⁴ Department of Endodontics, School of Dentistry, University of Washington, Seattle, WA, USA. Electronic address: avina@uw.edu.
⁵ Department of Materials Science and Engineering, University of Washington, Seattle, WA, USA; Department of Oral Health Science, School of Dentistry, University of Washington, Seattle, WA, USA; Department of Restorative Dentistry, School of Dentistry, University of Washington, Seattle, WA, USA. Electronic address: darola@uw.edu.
⁶ Department of Prosthodontics, Nanchang University, Nanchang, Jiangxi, China. Electronic address: liaolan5106@163.com.
⁷ Department of Periodontics, School and Hospital of Stomatology, Shanxi Medical University, Taiyuan, Shanxi, China. Electronic address: rxy611@163.com.
⁸ Department of Restorative Dentistry, School of Dentistry, University of Washington, Seattle, WA, USA. Electronic address: haizhang@uw.edu.

PMID: 35183920
DOI: 10.1016/j.archoralbio.2022.105371

Abstract

Objectives: The aims of the study were to evaluate the roles of odontoblast apoptosis in the progression of tubular sclerosis of teeth from donors at different ages and assess its correlation to chemical composition and mechanical properties.

Design: Healthy human teeth were obtained and divided into young (age ≤ 25, n = 12) and old (age ≥ 60, n = 12) groups. Odontoblasts were counted with standard hematoxylin and eosin staining. Odontoblast apoptosis within dentinal tubules was determined by cleaved caspase-3 immunostaining. Teeth in each group were evaluated by dynamic nanoindentation and energy-dispersive X-ray spectroscopy (EDS).

Results: The number of odontoblasts decreased significantly with age. The most prominent change occurred in the apical third of roots. Odontoblastic apoptosis was visualized within dentinal tubules. The apoptosis staining fraction was significantly higher in the outer and inner dentin of old teeth when compared with young teeth (p < 0.05). EDS showed increased calcium content in peritubular dentin but a decrease in the intertubular dentin with increasing age. Scanning based nanoindentation showed that the old intertubular dentin exhibited a significantly higher elastic modulus.

Conclusions: Odontoblast apoptosis, starting at the cell extension in dentinal tubules and proceeding from outer to inner dentin, contributes to the stoichiometric Ca/P ratio in peritubular dentin, which is potentially responsible for intratubular mineralization due to an imbalance of calcium and phosphorous ions.

Keywords: Ageing; Apoptosis; Odontoblast; Tubular sclerosis.

MeSH terms

Aging
Apoptosis
Dentin
Dentin, Secondary*
Humans
Odontoblasts*