DENTAL MATERIALS
Original Articles
IN VITRO WEAR OF THREE BULK FILL COMPOSITES AND ENAMEL
Jean-François Roulet 1 * , Nader Abdulhameed 2 , Chiayi Shen 3
Department of Restorative Dental Sciences , Center for Dental Biomaterials , College of Dentistry , University of Florida , 1395 Center Drive , Gainesville , Fl 32608 USA
1
Dr . med . dent , Dr . hc ., Professor , Director of Center for Dental Biomaterials
2
BDS , MS , PhD Student , Clinical Assistant Professor
3
PhD , Associate Professor
Received : November 11 , 2017
Revised : November 25 , 2017 Acccepted : December 12 , 2017 Published : December 13 , 2017
Academic Editor : David C . Watts , BSc , PhD , DSc , FInstP , FRSC , FRSB , FADM , Professor of Biomaterials Science , School of Dentistry , The University of Manchester , Manchester , M13 9PL United Kindom
Cite this article : Roulet J-F , Abdulhameed N , Shen C . In vitro Wear of Three Bulk Fill Composites and Enamel . Stoma Edu J . 2017 ; 4 ( 4 ): 248-253
ABSTRACT DOI : 10.25241 / stomaeduj . 2017.4 ( 4 ). art . 1
Introduction : This in vitro study aimed at testing the hypotheses that ( 1 ) there is no difference in wear in vitro among 3 bulk-fill composites investigated and their respective antagonists , and ( 2 ) the tested bulk-fill wear is not different from enamel . Methodology : X-tra fil ( Voco ; [ X ]), Tetric-N-Ceram Bulkfill ( Ivoclar Vivadent ; [ T ]), QuiXX ( Dentsply ; [ Q ]), and enamel [ E ] specimens ( Ø = 8 mm , depth = 1.5 mm , n = 8 / material ) were subjected to wear in a chewing simulator ( CS 4.8 , SD Mechatronik ) with steatite antagonists ( Ø = 6mm ). 1.2x10 5 cycles ( 0- 49 N , 0.7 mm lateral movement , 1 Hz ) were performed while simultaneously thermocycling ( 5 / 55 ° C ) every 90 s . The volumetric wear of the materials was measured with a 3D laser scanner . Results : The total wear of bulk-fills was : [ X ]: 0.64 ± 0.07 mm 3 ; [ T ]: 0.66 ± 0.08 mm 3 ; [ Q ]: 1.58 ± 0.14 mm 3 . The total wear of enamel ( 0.24 ± 0.03 mm 3 ) was significantly lower than that of the bulk-fills ( p < 0.0001 ). The total wear of the antagonists was : [ X ]: 0.32 ± 0.02 mm 3 ; [ T ]: 0.24 ± 0.04 mm 3 ; [ Q ]: 0.27 ± 0.02 mm 3 ; [ E ]: 0.12 ± 0.01 mm 3 . The wear of the antagonists by [ X ] was significantly higher than by [ T ] and [ Q ] ( p < 0.001 ). Enamel produced the lowest wear of the antagonists ( p < 0.0001 ). The wear was linear between 5x10 3 and 1.2x10 5 wear-cycles . A negative correlation between the wear of the composite materials and that of the antagonists was found . Conclusion : In vitro wear of Tetric-N-Ceram Bulkfill was in the expected range and equal to X-tra fil . QuiXX wear was 2.7 times higher . The antagonist wear was significantly lower , less than 50 % of the wear of the composites and the enamel . Both hypotheses were rejected . Keywords : chewing simulator , wear , bulk-fill composite , thermocycling , enamel .
1 . Introduction Approximately 5 years ago a new category of resin composites was introduced for bulk-filling deep and wide dental cavities . These new materials , called bulk-fill composites , are claimed to provide a faster and easier procedure than the traditional incremental restoration technique . 1-7 This innovation was introduced following the general marketing trend for faster , easier and more convenience in restorative dentistry . Bulk-fill resin composites are claimed to be placed up to 4 or 5 mm thick increments ( bulks ) skipping the time-consuming layering process , and cured with light exposure time of up to 20 s . 8 To accomplish this , the well-known and clinically proven resin chemistry and filler technology had to be modified in several aspects . The translucency of the material had to be increased to allow the blue light-curing wavelength to penetrate to the required depth of the material . 9 It was accomplished by either using less pigments and / or by matching the refractive index of the resin as closely as possible to those of the fillers in order to minimize the light scattering at the resin-filler interface . 8 Another possibility was to use more effective photo initiator systems ( e . g . germanium-based light-initiators , such as Ivocerin , Ivoclar Vivadent AG , Schaan , Liechtenstein ), which allow the composite to be cured with less light energy per cm 2 . 10 Furthermore , for bulk-fill composites it is beneficial to reduce the polymerization shrinkage stress , to reduce the stress challenge to the toothrestoration interface , thus allowing a good seal of the restauration by the adhesive system . One way to accomplish this is to minimize the resin content of the composite by using rather coarse fillers ( particle sizes much higher than 5-10 µ m ). Since the surface area of such particles is smaller , less resin is needed to wet it . 11 However , if this is done with conventional glass fillers , the surface characteristics and thus the polishability deteriorate . 12 A way around this is to use composite fillers having almost the same composition as the cured composite . They polish
* Corresponding author : Professor Jean-François Roulet , Dr . med . dent , Dr . hc ., Professor , Director of Center for Dental Biomaterials , Department of Restorative Dental Sciences , Center for Dental Biomaterials , College of Dentistry , University of Florida , 1395 Center Drive , Gainesville , Fl 32608 USA ; Phone + 1 352 273 5850 ; Fax : + 1 352 846 1643 , e-mail : jroulet @ dental . ufl . edu
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