Influence of increment thickness on dentin bond strength and light transmission of composite base materials.
OBJECTIVE
Bulk-fill resin composites (BFCs) are gaining popularity in restorative dentistry due to the reduced chair time and ease of application. This study aimed to evaluate the influence of increment thickness on dentin bond strength and light transmission of different BFCs and a new discontinuous fiber-reinforced composite.


METHODS
One hundred eighty extracted sound human molars were prepared for a shear bond strength (SBS) test. The teeth were divided into four groups (n = 45) according to the resin composite used: regular particulate filler resin composite: (1) G-ænial Anterior [GA] (control); bulk-fill resin composites: (2) Tetric EvoCeram Bulk Fill [TEBF] and (3) SDR; and discontinuous fiber-reinforced composite: (4) everX Posterior [EXP]. Each group was subdivided according to increment thickness (2, 4, and 6 mm). The irradiance power through the material of all groups/subgroups was quantified (MARC® Resin Calibrator; BlueLight Analytics Inc.). Data were analyzed using two-way ANOVA followed by Tukey's post hoc test.


RESULTS
SBS and light irradiance decreased as the increment's height increased (p < 0.05), regardless of the type of resin composite used. EXP presented the highest SBS in 2- and 4-mm-thick increments when compared to other composites, although the differences were not statistically significant (p > 0.05). Light irradiance mean values arranged in descending order were (p < 0.05) EXP, SDR, TEBF, and GA.


CONCLUSIONS
As increment thickness increased, the light transmission decreased for all tested resin composites. Discontinuous fiber-reinforced composite showed the highest value of curing light transmission, which was also seen in improved bonding strength to the underlying dentin surface.


CONCLUSIONS
Discontinuous fiber-reinforced composite can be applied safely in bulks of 4-mm increments same as other bulk-fill composites, although, in 2-mm thickness, the investigated composites showed better performance.
Turku Clinical Biomaterials Centre (TCBC), University of Turku, Turku, Finland. tarek.omran@utu.fi.|Department of Biomaterials Science, Institute of Dentistry, University of Turku, Lemminkäisenkatu 2, 20520, Turku, Finland. tarek.omran@utu.fi.|Finnish Doctoral Program in Oral Sciences (FINDOS), Institute of Dentistry, University of Turku, Turku, Finland. tarek.omran@utu.fi.
Tarek A
http://orcid.org/0000-0002-8343-6680
TA
Omran
Turku Clinical Biomaterials Centre (TCBC), University of Turku, Turku, Finland.|Department of Biomaterials Science, Institute of Dentistry, University of Turku, Lemminkäisenkatu 2, 20520, Turku, Finland.
Sufyan
S
Garoushi
Department of Biomaterials Science, Institute of Dentistry, University of Turku, Lemminkäisenkatu 2, 20520, Turku, Finland.|Department of Prosthetic Dentistry, Institute of Dentistry, University of Turku, Turku, Finland.|Department of General Practice, School of Dentistry, Virginia Commonwealth University, Richmond, Virginia, USA.
Aous A
AA
Abdulmajeed
Turku Clinical Biomaterials Centre (TCBC), University of Turku, Turku, Finland.|Department of Biomaterials Science, Institute of Dentistry, University of Turku, Lemminkäisenkatu 2, 20520, Turku, Finland.|Faculty of Health and Well-being, Turku University of Applied Sciences, Turku, Finland.
Lippo V
LV
Lassila
Turku Clinical Biomaterials Centre (TCBC), University of Turku, Turku, Finland.|Department of Biomaterials Science, Institute of Dentistry, University of Turku, Lemminkäisenkatu 2, 20520, Turku, Finland.|City of Turku Welfare Division, Oral Health Care, Turku, Finland.
Pekka K
PK
Vallittu
D003188:Composite Resins / Q000737:chemistry*; D001840:Dental Bonding / Q000379:methods*; D003764:Dental Materials / Q000737:chemistry*; D003799:Dental Stress Analysis; D003804:Dentin / Q000187:drug effects*; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D006801:Humans; D066298:In Vitro Techniques; D008027:Light; D008422:Materials Testing; D008963:Molar; D033081:Shear Strength; D013499:Surface Properties
D003188:Composite Resins; D003764:Dental Materials; D017220:Dentin-Bonding Agents; C000623314:G-aenial Bond; C000614714:SDR composite; C501891:Tetric EvoCeram
Bulk-fill composites; Composite base materials; Debonding test; Light irradiance; Shear bond strength; Thickness