Document Detail

Polymerization efficacy of simplified adhesive systems studied by NMR and MRI techniques.
MedLine Citation:
PMID:  16430954     Owner:  NLM     Status:  MEDLINE    
OBJECTIVE: To ascertain the efficacy of polymerization of self-etching dental adhesives in different solvent evaporation conditions. MATERIAL AND METHODS: Four self-etching adhesive systems were studied. Two of them are classified as mild two-step self-etching adhesives (Clearfil SE Bond, Protect Bond) and the other two are strong one-step systems (Xeno III, ADP-Prompt-L-Pop). The influence of temperature and duration of the air-drying period on photo-polymerization was followed by: gravimetry, (1)H solid-state NMR spectroscopy and stray-field MRI. The evolution of proton magnetization with irradiation time was recorded and correlated with volumetric polymerization shrinkage and extent of reaction; evaporation and hardening effects were identified. RESULTS: Main variables determining water-solvent evaporation of the tested adhesives are: (1) water/HEMA relative concentration, (2) presence of photoinitiator compounds in the primer (SEB) and (3) presence of ethanol (XENO). SEB shows the highest extent of photo-polymerization of the tested adhesives. The lowest volumetric contraction was obtained for APLP and XENO and the attempt to remove the solvents did not increase the extent of polymerization significantly. CONCLUSIONS: Temperature increase following photo-polymerization reaction is dominant towards the effect of the drying step for solvent evaporation in self-etching systems. Attempts to remove the solvents did not increase the extent of polymerization, so other problems are impairing the polymerization of one-step adhesives. CLINICAL SIGNIFICANCE: The use of tested one-step adhesives is discouraged as the attained low extent of polymerization may lead to low bond strength, high susceptibility to degradation and also will favor a continuing etching effect on the underlying dentin.
T G Nunes; F C P Garcia; R Osorio; R Carvalho; M Toledano
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2006-01-20
Journal Detail:
Title:  Dental materials : official publication of the Academy of Dental Materials     Volume:  22     ISSN:  0109-5641     ISO Abbreviation:  Dent Mater     Publication Date:  2006 Oct 
Date Detail:
Created Date:  2006-09-04     Completed Date:  2006-12-22     Revised Date:  2009-11-19    
Medline Journal Info:
Nlm Unique ID:  8508040     Medline TA:  Dent Mater     Country:  England    
Other Details:
Languages:  eng     Pagination:  963-72     Citation Subset:  D    
Departamento de Engenharia de Materiais/IST, Av. Rovisco Pais, 1, 1049-001 Lisboa, Portugal. <>
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MeSH Terms
Dental Bonding*
Dental Marginal Adaptation
Dental Stress Analysis
Dentin-Bonding Agents / chemistry,  radiation effects
Magnetic Resonance Imaging
Magnetic Resonance Spectroscopy
Materials Testing
Phase Transition
Resin Cements / chemistry*,  radiation effects*
Solvents / chemistry
Stress, Mechanical
Transition Temperature
Reg. No./Substance:
0/Dentin-Bonding Agents; 0/Resin Cements; 0/Solvents; 14875-96-8/Heme; 7732-18-5/Water

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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