RESTORATIVE DENTISTRY
IN VITRO WEAR OF 4 DIFFERENT UNIVERSAL COMPOSITES
Patricia Matias 1a, Jean-François Roulet 2b *, Nader Abdulhameed 2c, Chiayi Shen 2d
1
University of Brasilia, Department of Dentistry, Brasília DF 70910-900, Brazil
2
Department of Restorative Dental Sciences and Center of Dental Biomaterials, College of Dentistry, University of Florida, Gainesville FL 32610-0415, USA a
DDS student, Scientific Initiation Scholar b
DDS, PhD, Prof hc, Director of Center for Dental Biomaterials c
BDS, MS, Visiting scientist, Candidate PhD Material Sciences d
PhD, Professor
Cite this article: Matias P, Roulet JF, Abdulhameed N, Shen C. In vitro Wear of 4 different Universal Composites. Stoma Edu J. 2016; 3( 1): 39-46.
ABSTRACT
Received: January 27, 2016 Received in revised form: February 14, 2016
Accepted: April 22, 2016 Published online: February 10, 2016
Objectives: To test the hypotheses:( 1) there is no difference in the volumetric wear among composites tested, and( 2) there is no difference in the wear rates calculated from the linear relationship of wear increase over cycling. Methods: Two composites comprising pre-polymerized particles( Herculite-Précis [ H ], Tetric-N-Ceram [ T ]), one composite with very fine glass fillers( Charisma Opal [ C ]), and one composite with a mixture of agglomerated and nonagglomerated silica, and zirconia fillers( Filtek Z 350 XT [ F ]) were tested in a chewing simulator( CS 4.8, SD Mechatronik) with spherical Steatite antagonists( Ø 6 mm). Eight specimens of each composite were made by applying two increments in aluminum specimen-holders with a cylindrical cavity( Ø 8 mm, depth 1.5 mm), light cured( Bluephase G2; 1383 mW / cm2) for 20 s, polished to high gloss, and subjected to mastication cycles( 59 N, 1.2 Hz, lateral movement 0.7 mm) and thermocycles( 5 / 55 ° C; 116 s per cycle) simultaneously. After each 100, 500, 1,000, 2,000, 5,000, 10,000, 20,000, 30,000, 40,000, 50,000, 60,000, 70,000, 80,000, 90,000, 100,000, 110,000, and 120,000 mastication cycles, 3D images of worn surfaces were captured with Laserscanner LAS-20( SD Mechatronik), and volumetric wear in mm3 was calculated by Geomagic software. Results: Five samples were lost due to separation at interface between increments. The means of total volumetric wear( mean ± SD) after 120,000 cycles are 0.78 ± 0.26 mm3, 0.91 ± 0.15 mm3, 0.99 ± 0.29 mm3, and 1.15 ± 0.36mm3 for F, H, T and C. Wear rate of each surviving sample between 2,000 and 120,000 cycles was calculated by linear regression( R2 > 0.99 for all specimens). The wear rates( mean ± SD; μm3 / cycle) are, 5.97 ± 2.29x103, 6.85 ± 1.06x103, 8.91 ± 2.81x103 and 6.43 ± 0.58x103 for F, H, T and C. GLM shows statistically significant differences in the wear rate among the four materials( p = 0.0488). Looking at the total volumetric wear of the four composites) and wear of antagonists no differences were found( p = 0.1183( p = 0.3027) respectively. Conclusions: The first hypothesis was accepted and the second hypothesis was rejected. To prevent separation between increments, future specimen preparation should consider bulk fill. Keywords: composite, in vitro wear, chewing simulator.
1. Introduction
When composite resins were introduced to the market, depending on the filler content, some of them were recommended for anterior and posterior use. Adaptic( Johnson & Johnson, New Brunswick NJ, USA) composite material was chosen for a clinical study primarily based on mechanical and physical data. 1 Furthermore the authors reported wear results obtained with a tooth brushing machine. Adaptic showed similar wear as compared to amalgam, when abraded with a slurry of heavy CaCO 3
, though 4x less wear when abraded with pumice. This was not clinically confirmed. In a 3-year report, the same authors 2 using the USPHS criteria for evaluating restorations described a dramatic decrease in the quality of the occlusal anatomy from 44“ Alpha” at baseline to 6“ Alpha” and 36“ Bravo” ratings, which was interpreted as wear. This result was confirmed by Roulet et al. 3 However, the wear in that study was measured using a 3 coordinate measuring machine. Using a 100 µ m grid the x, y, and z coordinates, wear was determined at approximately 60 points per occlusal surface. The average vertical wear after 3
* Corresponding author:
Professor Jean-François Roulet, DDS, PhD, Prof hc, Director of Center for Dental Biomaterials Department of Restorative Dental Sciences College of Dentistry University of Florida 1395 Center Drive, Room D9-6 PO Box 100415, Gainesville FL 32610-0415, USA Tel / Fax:( 352) 273-5850, e-mail: JRoulet @ dental. ufl. edu
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