Elution of leachable components from resin composites after plasma arc vs standard or soft-start halogen light irradiation.
OBJECTIVE
To determine the release of leachable components from resin based composites (RBC) after plasma arc vs. standard or soft-start halogen curing.


METHODS
The tested RBC were the fine hybrids Herculite XRV (Kerr), Solitaire 2 (Kulzer) and Z250 (3M), the micro-fill Silux Plus (3M) and the polysiloxane-containing Definite (Degussa). The irradiation protocols included halogen standard irradiation at three different intensities (TriLight, ESPE), ramp curing (dito), step curing (HiLight, ESPE), pulse polymerization (VIP Light, BISCO) and plasma curing (Apollo 95E, DMDS; PAC Light, ADT). Initial solubility was determined applying RBC into simulated cavities (molds of 6mm inner diameter and 2mm height fabricated from pressed ceramics) and eluting 24h in demineralized water at 37 degrees C. Medium-term solubility was evaluated using plain RBC specimens of equivalent dimensions stored dark (37 degrees C, 24h) and extracted in 50% CH(3)OH (37 degrees C, 72 h). After drying the specimens to constant weight, solubility and sorption were determined gravimetrically.


RESULTS
Medium-term solubility/sorption were higher than initial ones. Irradiation at reduced intensity increased solubility and sorption, whereas ramp curing, step curing and pulse polymerization (for most materials) maintained low values. Plasma arc curing worked well for Z250 and Herculite XRV, compared to medium or low intensity halogen irradiation for Silux Plus and Definite and produced moderately (PAC Light) or very (Apollo 95E) high solubility for Solitaire 2.


CONCLUSIONS
Reducing irradiation intensity does and soft-start protocols do not compromise solubility and sorption. The efficiency of plasma arc curing depends markedly on the types of photo-initiators used.
Hofmann
Norbert
N
Department of Operative Dentistry and Periodontology, Bavarian Julius-Maximilian-University of Würzburg, Pleicherwall 2, D-97070, Würzburg, Germany. norbert.hofmann@mail.uni-wuerzburg.de
Renner
Jan
J
Hugo
Burkard
B
Klaiber
Bernd
B
D000704:Analysis of Variance; D003188:Composite Resins / Q000737:chemistry* / Q000528:radiation effects; D003793:Dental Restoration, Permanent / Q000295:instrumentation*; D006801:Humans; D008027:Light; D008029:Lighting / Q000295:instrumentation*; D008422:Materials Testing; D011108:Polymers / Q000737:chemistry / Q000528:radiation effects; D011829:Radiation Dosage; D019279:Resin Cements / Q000737:chemistry / Q000528:radiation effects; D012833:Siloxanes / Q000737:chemistry / Q000528:radiation effects; D012995:Solubility; D013223:Statistics as Topic; D013499:Surface Properties; D013696:Temperature; D013729:Terpenes / Q000737:chemistry / Q000528:radiation effects; D013997:Time Factors; D014867:Water
D003188:Composite Resins; C421785:Definite composite resin; C444701:Filtek Z250; D011108:Polymers; D019279:Resin Cements; D012833:Siloxanes; C469658:Solitaire 2 composite resin; D013729:Terpenes; D014867:Water; C065770:Herculite XR; C074741:Silux Plus