PMID- 32035660
OWN - NLM
STAT- MEDLINE
DCOM- 20210303
LR  - 20210303
IS  - 1873-2380 (Electronic)
IS  - 0021-9290 (Linking)
VI  - 101
DP  - 2020 Mar 5
TI  - Regional contribution of proteoglycans to the fracture toughness of the dentin 
      extracellular matrix.
PG  - 109633
LID - S0021-9290(20)30040-3 [pii]
LID - 10.1016/j.jbiomech.2020.109633 [doi]
AB  - This study investigated the contribution of small leucine rich proteoglycans 
      (SLRPs) to the fracture toughness of the dentin extracellular matrix (ECM) by 
      enzymatically-assisted selective removal of glycosaminoglycan chains (GAGs) and 
      proteoglycans (PGs) core protein. We adapted the Mode III trouser tear test to 
      evaluate the energy required to tear the dentin ECM. Trouser-shaped dentin 
      specimens from crown and root were demineralized. Depletion of GAGs and PGs 
      followed enzymatic digestion using chondroitinase ABC (c-ABC) and matrix 
      metalloproteinase 3 (MMP-3), respectively. The legs from specimen were stretched 
      under tensile force and the load at tear propagation was determined to calculate 
      the tear energy (T, kJ/m(2)). SLRPs decorin and biglycan were visualized by 
      immunohistochemistry and ECM tear pattern was analyzed in SEM. Results showed T 
      of crown ECM was not affected by PGs/GAGs depletion (p = 0.799), whereas the 
      removal of PGs significantly reduced T in root dentin ECM (p = 0.001). Root 
      dentin ECM exhibited higher T than crown (p < 0.03), however no regional 
      difference are present after PG depletion (p = 0.480). Immunohistochemistry 
      confirmed removal of GAGs and PGs. SEM images showed structural modifications 
      after PGs/GAGs removal such as enlargement of dentinal tubules, increased 
      interfibrillar spaces and presence of untwisted fibrils with increased diameter. 
      Findings indicate that the capacity of the PGs to unfold and untwist contribute 
      to the dentin ECM resistance to tear, possibly influencing crack growth 
      propagation. The regional differences are likely an evolutionary design to 
      increase tooth survival, that undergoes repetitive mechanical loading and load 
      stress dissipation over a lifetime of an individual.
CI  - Copyright (c) 2020 Elsevier Ltd. All rights reserved.
FAU - Alania, Yvette
AU  - Alania Y
AD  - Department of Restorative Dentistry, College of Dentistry, University of Illinois 
      at Chicago, 801 South Paulina St, Chicago, IL 60612, USA.
FAU - Creighton, Johnathon
AU  - Creighton J
AD  - Department of Restorative Dentistry, College of Dentistry, University of Illinois 
      at Chicago, 801 South Paulina St, Chicago, IL 60612, USA.
FAU - Trevelin, Livia T
AU  - Trevelin LT
AD  - Department of Restorative Dentistry, College of Dentistry, University of Illinois 
      at Chicago, 801 South Paulina St, Chicago, IL 60612, USA; Department of 
      Restorative Dentistry, School of Dentistry, Municipal University of Sao Caetano 
      do Sul, Rua Santo Antonio 50, Sao Caetano do Sul, Sao Paulo 09521-160, Brazil.
FAU - Zamperini, Camila A
AU  - Zamperini CA
AD  - Department of Restorative Dentistry, College of Dentistry, University of Illinois 
      at Chicago, 801 South Paulina St, Chicago, IL 60612, USA.
FAU - Bedran-Russo, Ana K
AU  - Bedran-Russo AK
AD  - Department of Restorative Dentistry, College of Dentistry, University of Illinois 
      at Chicago, 801 South Paulina St, Chicago, IL 60612, USA. Electronic address: 
      bedran@uic.edu.
LA  - eng
PT  - Journal Article
PT  - Research Support, N.I.H., Extramural
DEP - 20200116
PL  - United States
TA  - J Biomech
JT  - Journal of biomechanics
JID - 0157375
RN  - 0 (Glycosaminoglycans)
SB  - IM
MH  - Biomechanical Phenomena
MH  - Dentin/*cytology/*injuries
MH  - Extracellular Matrix/*metabolism
MH  - Glycosaminoglycans/*metabolism
MH  - Humans
MH  - Mechanical Phenomena
OTO - NOTNLM
OT  - Collagen
OT  - Dentin
OT  - Glycosaminoglycans
OT  - Proteoglycans
OT  - Tear energy
COIS- Declaration of Competing Interest The authors declared that there is no conflict 
      of interest.
EDAT- 2020/02/10 06:00
MHDA- 2021/03/04 06:00
CRDT- 2020/02/10 06:00
PHST- 2019/09/11 00:00 [received]
PHST- 2020/01/06 00:00 [revised]
PHST- 2020/01/12 00:00 [accepted]
PHST- 2020/02/10 06:00 [pubmed]
PHST- 2021/03/04 06:00 [medline]
PHST- 2020/02/10 06:00 [entrez]
AID - S0021-9290(20)30040-3 [pii]
AID - 10.1016/j.jbiomech.2020.109633 [doi]
PST - ppublish
SO  - J Biomech. 2020 Mar 5;101:109633. doi: 10.1016/j.jbiomech.2020.109633. Epub 2020 
      Jan 16.