Influence of new light curing units and bonding agents on the microleakage of Class V composite resin restorations.
OBJECTIVE
To evaluate the influence of four light curing units on the stress induced by polymerization of two dentin bonding systems and a composite resin.


METHODS
Standardized kidney-shaped Class V cavities were prepared on the buccal and lingual surfaces at approximately 1 mm below the cemento-enamel junction (2 mm deep, 6-7 mm wide and 2 mm high). Two dentin bonding systems (DBS), Single Bond (SB), Optibond Solo Plus (OS+), and four light curing units (LCU): Astralis 7 (mode HIP 40 seconds), Elipar Highlight (soft start polymerization 40 seconds), GC e Light (8 mm tip) (fast cure of 12 seconds), and Optilux 501 (turbo tip) (fast cure of 10 seconds) were tested. The preparations were restored using the same microfilled composite (Filtek A110, shade A3). The teeth were thermocycled, immersed in a dye solution and sectioned. The enamel failures and the occlusal and cervical dentin microleakages were measured.


RESULTS
No enamel and occlusal dentin microleakage was found. Concerning cervical dentin microleakage, with Single Bond, no significant difference was noted for all the light curing units (P< 0.05). With OptiBond Solo Plus, the filled adhesive, only two, the LCU Elipar and GC e Light, presented no statistical difference when all of the others exhibited statistical differences among themselves. The light intensity, the exposure duration, and the light source of the LCU are important parameters. When comparing the influence of the dentin adhesive, OS+ presented results significantly greater than SB, depending upon which lights were used. The Optilux 501 showed no significant difference. To act as a shock absorber, the adhesive needs to have time to compensate for the polymerization shrinkage.
Dental Biomaterials Laboratory, Faculty of Dental Surgery, Department of Operative Dentistry and Endodontics, University Paris 7-Denis Diderot, Antony, France. nx.pradelle@oreka.com
Nelly
N
Pradelle-Plasse
Catherine
C
Besnault
Nechad
N
Souad
Pierre
P
Colon
D017438:Bisphenol A-Glycidyl Methacrylate; D003188:Composite Resins / Q000528:radiation effects*; D001840:Dental Bonding / Q000379:methods*; D003737:Dental Cavity Preparation; D003748:Dental Equipment; D003763:Dental Leakage; D018772:Dental Marginal Adaptation; D003793:Dental Restoration, Permanent; D003799:Dental Stress Analysis; D017220:Dentin-Bonding Agents; D011211:Electric Power Supplies; D006801:Humans; D008027:Light; D008422:Materials Testing; D011108:Polymers / Q000737:chemistry; D019279:Resin Cements
D003188:Composite Resins; D017220:Dentin-Bonding Agents; C452225:Filtek A110 composite resin; C451600:OptiBond Solo Plus; D011108:Polymers; D019279:Resin Cements; C115612:single bond; D017438:Bisphenol A-Glycidyl Methacrylate