An investigation into the effect of a resin infiltrant on the micromechanical properties of hypomineralised enamel.
BACKGROUND
Resin infiltration may alter the mechanical properties of enamel hypomineralised lesions (HL); however, variable surface layer (SL) thickness may affect resin penetration.


OBJECTIVE
To determine the thickness of the SL of HL and to investigate the effect of resin infiltration on the mechanical properties of HL.


METHODS
The thickness of the SL over HL was determined using polarised light microscopy. Etching time using 15% HCl gel to remove the SL of 52 samples was determined. Selected HL and control areas of 21 teeth were infiltrated with Icon®resin infiltrant, and cross-sectional Knoop microhardness (KHN) measurements were recorded before and after resin infiltration.


RESULTS
Ninety-six point five per cent of HL had a detectable SL with mean thickness of 58 ± 29 μm. Application of HCl for 120 s produced a mean MIH erosion depth of 58 ± 12 μm. Eleven of 21 samples had evidence of infiltration using visual examination. The infiltrant penetrated some of the HL leading to an increase in KHN (111 ± 75 KHN) which, when compared to adjacent non-infiltrated HL (96 ± 52 KHN), was not statistically significantly different (P = 0.56).


CONCLUSIONS
There was marked variation in the SL thickness of HL. Resin infiltration of HL did not increase microhardness significantly.
Oral Health Cooperative Research Centre, Melbourne Dental School, The University of Melbourne, Melbourne, Australia.|Boston Children's Hospital and Harvard School of Dental Medicine, Boston, MA, USA.
Harleen
H
Kumar
Oral Health Cooperative Research Centre, Melbourne Dental School, The University of Melbourne, Melbourne, Australia.
Joseph Emilio Aurelio
JEA
Palamara
Oral Health Cooperative Research Centre, Melbourne Dental School, The University of Melbourne, Melbourne, Australia.
Michael Francis
MF
Burrow
Oral Health Cooperative Research Centre, Melbourne Dental School, The University of Melbourne, Melbourne, Australia.
David John
http://orcid.org/0000-0002-4570-0620
DJ
Manton
D003743:Dental Enamel / Q000737:chemistry / Q000000981:diagnostic imaging / Q000187:drug effects* / Q000473:pathology*; D045662:Dental Etching / Q000009:adverse effects; D006244:Hardness; D006801:Humans; D066298:In Vitro Techniques; D055595:Mechanical Phenomena / Q000187:drug effects*; D012117:Resins, Synthetic / Q000494:pharmacology*; D013499:Surface Properties; D013997:Time Factors; D017001:Tooth Demineralization / Q000000981:diagnostic imaging / Q000473:pathology
D012117:Resins, Synthetic; C578177:icon infiltrant