Water content in experimental dentine primers to minimize the contraction gap width of a light-cured resin composite.
OBJECTIVE
The effect of water content in experimental dentine primers consisting of an aqueous solution of either glyceryl methacrylate (GM) or hydroxyethyl methacrylate (HEMA), and in experimental self-etching dentine primers composed of methacryloxyethyl hydrogen phenyl phosphate (Phenyl-P), was evaluated by measuring the wall-to-wall polymerization contraction gap width of a commercial light-activated resin composite filled in a cylindrical dentine cavity prepared in an extracted human molar.


METHODS
A commercial light-cured dentine bonding agent was applied to the cavity after cleaning with EDTA and priming with either GM or HEMA, or after self-etching priming by Phenyl-P diluted in either GM or HEMA solution.


RESULTS
In the GM and HEMA solutions, the gap width was minimized when the water content was 65 wt% even though gap formation could not be prevented by HEMA solution. With the self-etching dentine primers, gaps could not be observed under the light microscope with 16 wt% Phenyl-P diluted in 35 wt% GM or HEMA or with 20 wt% Phenyl-P diluted in 20 wt% GM or HEMA.


CONCLUSIONS
The water content in both the experimental dentine primers and the self-etching dentine primers which yielded the minimum contraction gap width for the resin composite in the dentine cavity was approximately 60 wt%.
Yokoi
K
K
Department of Operative Dentistry, Showa University School of Dentistry, Tokyo, Japan.
Miyaji
H
H
Itoh
K
K
Hisamitsu
H
H
Wakumoto
S
S
D003188:Composite Resins / Q000737:chemistry*; D018772:Dental Marginal Adaptation; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D005989:Glycerides / Q000737:chemistry; D016018:Least-Squares Analysis; D008689:Methacrylates / Q000737:chemistry; D009943:Organophosphorus Compounds / Q000737:chemistry; D019279:Resin Cements; D014867:Water
D003188:Composite Resins; D017220:Dentin-Bonding Agents; D005989:Glycerides; D008689:Methacrylates; D009943:Organophosphorus Compounds; C074232:Phenyl-P adhesion promoting monomer; D019279:Resin Cements; D014867:Water; C074669:Clearfil Photo Bond; C074741:Silux Plus; C069750:glyceryl methacrylate; C005044:hydroxyethyl methacrylate