PMID- 25498989
OWN - NLM
STAT- MEDLINE
DCOM- 20161213
LR  - 20161230
IS  - 1879-0097 (Electronic)
IS  - 0109-5641 (Linking)
VI  - 31
IP  - 3
DP  - 2015 Mar
TI  - Analysis of stress relaxation in temporization materials in dentistry.
PG  - e55-62
LID - S0109-5641(14)00656-3 [pii]
LID - 10.1016/j.dental.2014.11.004 [doi]
AB  - OBJECTIVE: Although temporization is intended as an interim step, complexity of 
      individual treatment situations may demand medium to longer term use of temporary 
      appliances in clinical practice. The durability and integrity of these 
      restorations for continued use to meet the treatment demands is therefore an 
      important clinical problem. The goal of this study was to evaluate the short to 
      medium term stability of these materials under controlled loading to study their 
      stress relaxation behavior. METHODS: Acrylic resins (poly(methyl) and poly(ethyl) 
      methacrylate) and bis-acryl composite resins were tested in vitro in this study. 
      The stress decay data with time (under an applied constant strain) due to 
      internal strain caused by molecular relaxation were systematically analyzed using 
      important parameters derived from stress changes with time. RESULTS AND 
      SIGNIFICANCE: The results showed significant differences in the stress relaxation 
      behavior between different materials which may have significant bearing on their 
      durability in medium to longer term interim clinical applications. Poly(ethyl) 
      methacrylate (PEMA) resins subjected to applied constant strain over a period of 
      time showed large time dependent decay of applied stress, indicating very high 
      internal molecular relaxation effects, relative to those of poly(methyl) 
      methacrylate (PMMA) and bis-acryl composites. The results showed that PMMA and 
      composite resins were superior in their ability to maintain constant strain 
      without excessive dissipation of applied stress than PEMA resin. This suggests 
      that internal strain caused by molecular relaxation events may lead to excessive 
      dimensional instability in PEMA.
CI  - Copyright (c) 2014 Academy of Dental Materials. Published by Elsevier Ltd. All 
      rights reserved.
FAU - Vaidyanathan, Tritala
AU  - Vaidyanathan T
AD  - Department of Restorative Dentistry, Rutgers School of Dental Medicine, Newark, 
      NJ, USA. Electronic address: vaidyatk@hotmail.com.
FAU - Vaidyanathan, Jayalakshmi
AU  - Vaidyanathan J
AD  - Department of Restorative Dentistry, Rutgers School of Dental Medicine, Newark, 
      NJ, USA.
FAU - Manasse, Maryse
AU  - Manasse M
AD  - Department of Restorative Dentistry, Rutgers School of Dental Medicine, Newark, 
      NJ, USA.
LA  - eng
PT  - Journal Article
DEP - 20141209
PL  - England
TA  - Dent Mater
JT  - Dental materials : official publication of the Academy of Dental Materials
JID - 8508040
RN  - 0 (Acrylic Resins)
RN  - 0 (Composite Resins)
RN  - 9011-14-7 (Polymethyl Methacrylate)
MH  - Acrylic Resins/*chemistry
MH  - Composite Resins/*chemistry
MH  - *Dental Restoration, Temporary
MH  - Elastic Modulus
MH  - Materials Testing
MH  - Pilot Projects
MH  - Polymethyl Methacrylate/*chemistry
MH  - Stress, Mechanical
MH  - Surface Properties
MH  - Temperature
MH  - Time Factors
OTO - NOTNLM
OT  - Relaxation modulus
OT  - Stress relaxation
OT  - Temporization materials
OT  - Time and temperature dependence
EDAT- 2014/12/17 06:00
MHDA- 2016/12/15 06:00
CRDT- 2014/12/16 06:00
PHST- 2014/09/19 00:00 [received]
PHST- 2014/11/04 00:00 [accepted]
PHST- 2014/12/16 06:00 [entrez]
PHST- 2014/12/17 06:00 [pubmed]
PHST- 2016/12/15 06:00 [medline]
AID - S0109-5641(14)00656-3 [pii]
AID - 10.1016/j.dental.2014.11.004 [doi]
PST - ppublish
SO  - Dent Mater. 2015 Mar;31(3):e55-62. doi: 10.1016/j.dental.2014.11.004. Epub 2014 
      Dec 9.