Inlay shading effect on the photopolymerization kinetic of a dental composite material used as bonding system in an indirect restoration technique.
OBJECTIVE
To define the inlay shading effect on the polymerization levels and kinetics of a light activated bonding system for an indirect restoration technique.


METHODS
For the bonding system, an adhesive: Excite (Ivoclar-vivadent) and a composite: Z250 (3M-ESPE, St Paul Minnesota, USA) were investigated. A Demetron (Kerr USA) light curing unit was used. The composite inlay blocks of 2 mm thick were used for the experiment (Artglass A2 Heraeus, Kulzer, Dormagen, Germany). The bonding composite was photocured using a 2 mm composite inlay block as a shielding system while the adhesive was shielded by a 2.3 mm thick wafer, composed of the inlay material and the previously cured bonding composite. The kinetics and levels of polymerization were measured by a differential scanning calorimeter technique (DSC 25, Mettler, Orange, CA, Toledoh, küsnacht, switzerland).


RESULTS
The inlay shielded dental composite reaches a significantly lower level of polymerization compared to the unshielded composite. Inlay shielded composite, has a slower polymerization kinetic compared to unshielded composite. The resin adhesive shielded by the inlay-composite wafer reaches polymerization values not significantly different from those of the unshielded adhesive.


CONCLUSIONS
The degree of cure of the light-cured composite resins for use as a base for indirect composite restorations, may be severely reduced as a result of inlay shielding.
Simeone
Michele
M
School of Dentistry, University of Naples FEDERICO II, Italy.
Lanza
Alessandro
A
Rengo
Sandro
S
Aversa
Raffaella
R
Apicella
Davide
D
Apicella
Antonio
A
D002152:Calorimetry, Differential Scanning; D003188:Composite Resins / Q000737:chemistry* / Q000528:radiation effects; D001840:Dental Bonding / Q000379:methods*; D003793:Dental Restoration, Permanent / Q000295:instrumentation / Q000379:methods*; D006801:Humans; D007284:Inlays; D007700:Kinetics; D008027:Light; D008029:Lighting / Q000295:instrumentation; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D011108:Polymers / Q000737:chemistry / Q000528:radiation effects
C498018:Artglass (dental composite); D003188:Composite Resins; C420130:Excite cement; C444701:Filtek Z250; D008689:Methacrylates; D011108:Polymers