Class II composite resin restorations with two polymerization techniques: relationship between microtensile bond strength and marginal leakage.
OBJECTIVE
To determine the relationship between leakage and microtensile bond strength in the same specimen of direct Class II composite restorations performed with two polymerization techniques.


METHODS
Class II slot preparations were made in 40 non-carious human third molars and restored using Single Bond and P-60 (3M ESPE) according to the manufacturer's indications. Half of the preparations had the cervical margin in enamel and half in dentin. Teeth were incrementally restored either with direct polymerization from occlusal surface or with indirect polymerization through translucent matrices and reflective wedges. Teeth were isolated with nail varnish and immersed in fucsin for 24h. Subsequently, they were sectioned into slabs that were measured for leakage (mm), and trimmed to obtain hour-glass shaped specimens for microtensile bond test. Fractured specimens were examined under magnification (40 x) to evaluate the fracture mode. Data were analyzed with Mann-Whitney and Kruskal-Wallis (microleakage), two-way ANOVA and Student-Newman-Keuls tests (bond strength). The relationship between microleakage and microtensile bond strength were analyzed with Spearman's correlation test.


RESULTS
There were no significant effects of polymerization technique and margin location on both leakage and bond strength (p>0.05). Bond strengths were higher in preparations with enamel margins than in preparations with dentin margins, when restored with indirect polymerization technique (p<0.05). No significant correlation was found between leakage and bond strength (p>0.05).


CONCLUSIONS
Polymerization techniques had no influence on microleakage and bond strength of Class II composite restorations, and there was no relationship between these variables when evaluated in the same specimen.
Cenci
MaximilianoSérgio
M
Department of Operative Dentistry, School of Dentistry, Federal University of Pelotas, Pelotas, RS, Brazil.
Demarco
FlávioFernando
F
de Carvalho
RicardoMarins
R
D000704:Analysis of Variance; D017438:Bisphenol A-Glycidyl Methacrylate / Q000528:radiation effects; D003188:Composite Resins / Q000528:radiation effects*; D001840:Dental Bonding; D003737:Dental Cavity Preparation; D003763:Dental Leakage / Q000517:prevention & control; D018772:Dental Marginal Adaptation; D003793:Dental Restoration, Permanent / Q000379:methods*; D003799:Dental Stress Analysis; D006801:Humans; D008027:Light; D008422:Materials Testing; D044367:Phase Transition; D011897:Random Allocation; D019279:Resin Cements / Q000528:radiation effects*; D018709:Statistics, Nonparametric; D013718:Tensile Strength; D019237:Tooth Cervix
D003188:Composite Resins; C443708:P60 Condensible Resin Composite; D019279:Resin Cements; C115612:single bond; D017438:Bisphenol A-Glycidyl Methacrylate