Scand. J. Dent. Res. 1978:
S6:399-'iOS
(Key words: dental materials; composite re sins;fissure sealing
Abrasive wear of filled and unfilled resins in vitro MAGNE RAADAL Department of Pedodontics and Department of Dental Materials, University of Bergen, Bergen, Norway
ABSTRACT - The present investigation was initiated to evaluate the wear resistance of filled and unfilled resins which may be suitable for fissure sealing. Two commercial unfilled resins (Adaptic Glaze® and Delton*), three degrees of diluted composite (Adaptic® diluted with Adaptic Bonding Agent®) and undiluted composite (Adaptic) were studied. Abrasion was caused by 400-grit silicon carbide paper in a mechanical surface grinder. Ten specimens of each of the material samples were tested. The unfilled resins were abraded tfiree to six times more readily than the composite samples. Undiluted composite was the most resistant, whereas samples of increasing degrees of dilution were abraded to increasing extents. However, even the most diluted composite, although very fluid, was at least three times more resistant than the unfilled samples. The results of this study indicate that adding inorganic filler particles to a resin, even in small amounts, greatly enhances the wear resistance of such materials. (Accepted for publication 15 June 1978)
The content of inorganic filler particles seems to be an important factor for the resistance to abrasive wear of resin materials. Clinical and technical studies have shown that composites are more resistant to wear than unfilled acrylic or BisGMA-resins (POWERS, ALLEN & CRAIG 1974, LEINFELDER, SLUDER, SOCKWELL, STRICKLAND ic WALL 1975, EAMES, O'NEAL & ROGERS 1976, HARRISON & DRAUGHN 1976).
The susceptibility to abrasive wear is probably an important factor for the durability of fissure sealants. In his clinical studies ULVESTAD (1976 a, b) has found a very high percentage of retention when a diluted composite resin was used, and resistance to wear due to the filler content is indicated as a contributing
factor to these findings. However, the significance of the amount of filler particles in the resin has not been thoroughly studied. Two types of in vitro abi asion tests have been used for resin materials, two-body and three-body tests (POWERS et al. 1974). Two-body abrasion is a process in which abrasive particles are attached to one of two rubbing surfaces. This test has been applied to dental materials using standard surfaces of silicon carbide paper or silicate glass. Two-body abrasion is probably representative of wear that occurs clinically on occlusal surfaces, cusps and incisal edges (POWERS et al. 1974). In three-body abrasion abrasive particles are introduced between two rubbing surfaces, as a brush and slurry method. This type of
RAADAL
400
abrasion is thought to be representative of prophylactic procedures, and occurs mostly on buccal and lingual surfaces (POWERS etal. 1974). The clinical relevance of laboratory studies has been questioned (AsMUSSEN 1976, EAMES g< al. 1976), and consequently the results of such tests ought to be confirmed by clinical tests. The purpose of this investigation was to evaluate the resistance to abrasive wear of resin materials which may be suitable for use as fissure sealants, and two-body abrasion was regarded as being most representative of wear that occurs on occlusal surfaces of teeth.
Table 1 Materials used in the study
Material
Batch No.
Adaptic Adaptic Bonding Agent Adaptic Glaze Dekon
4D021 0631 D 12 5 E008 3505 D 01
the table of a surface grinder. The steel rod, with the test specimen fixed to its end, was held stationary in a tube in such a way that the specimen rested with its long axis perpendicular to the table and under a constant load of 1.158 N (0.37 MPa) (Fig. 1).
Material and methods The materials used in this study were Adaptic®, Adaptic Bonding Agent®, Adaptic Glaze® and Dekon®, all manufactured by Johnson & Johnson (Table 1). The resins were all of the BisGMA type, and the inorganic component was quartz particles coated with a silane coupling agent. Adaptic Glaze and Delton were used by mixing equal amounts by weight of universal and catalyst components. Diludons of composite were produced by mixing different amounts of paste composite and Bonding Agent resin: Dilution mixture 1 (Mix. 1): 0.200 g of each paste + 0.085 g liquid resin. Dilution mixture 2 (Mix. 2): 0.100 g of each paste + 0.085 g liquid I'esin. Dilution mixture 3 (Mix. 3): 0.050 g of each paste -f-0.085 g liquid resin. The weights were accurate to 1 mg. Cylindrical specimens (2 mm in diameter, 4 mm in length) of each of the samples were made in a split brass die. After polymerization the specimens were fixed to the end of stainless steel rods by means of an epoxy glue (Araldite®). The specimens were stored dry at room temperature for 3 d, then immersed in water for another 2 d before testing. Abrasion was caused by 400-grit silicon carbide paper (Struers®) which was attached to
.STEEL ROD
TUBE , TEST SPECIMEN SILICON CARBIDE PAPER TABLE
Fig. 1. Schematic presentation of the surface grinder with a test specimen in it.
The table moved backwards and forwards a distance of 16.05 mm in each direction, the distance to and fro constituting one period. For each specimen the table was cycled 200 periods, representing a distance of 6,420 mm at an average speed of 19.03 mm/s. For every 50 periods the silicon carbide paper was changed. The rubbing surfaces were condnually flushed with distilled water to remove debris. Ten specimens of each of the material samples were tested. Wear was determined by measuring to the nearest 0.05 mm the reduction in length of the specimens by using a light microscope with a calibrated measuring eyepiece. The results were stadstically tested using Wilcoxon's signed-rank test (HAYSLETT& MURPHY 1971).
ABRASIVE WEAR OF RESINS Results
The relative amount of filler particles in the various composite samples is illustrated in Fig. 2. As can be observed the filler content decreased as the degree of dilution was increased. A significant difference (P
S6:399-'iOS
(Key words: dental materials; composite re sins;fissure sealing
Abrasive wear of filled and unfilled resins in vitro MAGNE RAADAL Department of Pedodontics and Department of Dental Materials, University of Bergen, Bergen, Norway
ABSTRACT - The present investigation was initiated to evaluate the wear resistance of filled and unfilled resins which may be suitable for fissure sealing. Two commercial unfilled resins (Adaptic Glaze® and Delton*), three degrees of diluted composite (Adaptic® diluted with Adaptic Bonding Agent®) and undiluted composite (Adaptic) were studied. Abrasion was caused by 400-grit silicon carbide paper in a mechanical surface grinder. Ten specimens of each of the material samples were tested. The unfilled resins were abraded tfiree to six times more readily than the composite samples. Undiluted composite was the most resistant, whereas samples of increasing degrees of dilution were abraded to increasing extents. However, even the most diluted composite, although very fluid, was at least three times more resistant than the unfilled samples. The results of this study indicate that adding inorganic filler particles to a resin, even in small amounts, greatly enhances the wear resistance of such materials. (Accepted for publication 15 June 1978)
The content of inorganic filler particles seems to be an important factor for the resistance to abrasive wear of resin materials. Clinical and technical studies have shown that composites are more resistant to wear than unfilled acrylic or BisGMA-resins (POWERS, ALLEN & CRAIG 1974, LEINFELDER, SLUDER, SOCKWELL, STRICKLAND ic WALL 1975, EAMES, O'NEAL & ROGERS 1976, HARRISON & DRAUGHN 1976).
The susceptibility to abrasive wear is probably an important factor for the durability of fissure sealants. In his clinical studies ULVESTAD (1976 a, b) has found a very high percentage of retention when a diluted composite resin was used, and resistance to wear due to the filler content is indicated as a contributing
factor to these findings. However, the significance of the amount of filler particles in the resin has not been thoroughly studied. Two types of in vitro abi asion tests have been used for resin materials, two-body and three-body tests (POWERS et al. 1974). Two-body abrasion is a process in which abrasive particles are attached to one of two rubbing surfaces. This test has been applied to dental materials using standard surfaces of silicon carbide paper or silicate glass. Two-body abrasion is probably representative of wear that occurs clinically on occlusal surfaces, cusps and incisal edges (POWERS et al. 1974). In three-body abrasion abrasive particles are introduced between two rubbing surfaces, as a brush and slurry method. This type of
RAADAL
400
abrasion is thought to be representative of prophylactic procedures, and occurs mostly on buccal and lingual surfaces (POWERS etal. 1974). The clinical relevance of laboratory studies has been questioned (AsMUSSEN 1976, EAMES g< al. 1976), and consequently the results of such tests ought to be confirmed by clinical tests. The purpose of this investigation was to evaluate the resistance to abrasive wear of resin materials which may be suitable for use as fissure sealants, and two-body abrasion was regarded as being most representative of wear that occurs on occlusal surfaces of teeth.
Table 1 Materials used in the study
Material
Batch No.
Adaptic Adaptic Bonding Agent Adaptic Glaze Dekon
4D021 0631 D 12 5 E008 3505 D 01
the table of a surface grinder. The steel rod, with the test specimen fixed to its end, was held stationary in a tube in such a way that the specimen rested with its long axis perpendicular to the table and under a constant load of 1.158 N (0.37 MPa) (Fig. 1).
Material and methods The materials used in this study were Adaptic®, Adaptic Bonding Agent®, Adaptic Glaze® and Dekon®, all manufactured by Johnson & Johnson (Table 1). The resins were all of the BisGMA type, and the inorganic component was quartz particles coated with a silane coupling agent. Adaptic Glaze and Delton were used by mixing equal amounts by weight of universal and catalyst components. Diludons of composite were produced by mixing different amounts of paste composite and Bonding Agent resin: Dilution mixture 1 (Mix. 1): 0.200 g of each paste + 0.085 g liquid resin. Dilution mixture 2 (Mix. 2): 0.100 g of each paste + 0.085 g liquid I'esin. Dilution mixture 3 (Mix. 3): 0.050 g of each paste -f-0.085 g liquid resin. The weights were accurate to 1 mg. Cylindrical specimens (2 mm in diameter, 4 mm in length) of each of the samples were made in a split brass die. After polymerization the specimens were fixed to the end of stainless steel rods by means of an epoxy glue (Araldite®). The specimens were stored dry at room temperature for 3 d, then immersed in water for another 2 d before testing. Abrasion was caused by 400-grit silicon carbide paper (Struers®) which was attached to
.STEEL ROD
TUBE , TEST SPECIMEN SILICON CARBIDE PAPER TABLE
Fig. 1. Schematic presentation of the surface grinder with a test specimen in it.
The table moved backwards and forwards a distance of 16.05 mm in each direction, the distance to and fro constituting one period. For each specimen the table was cycled 200 periods, representing a distance of 6,420 mm at an average speed of 19.03 mm/s. For every 50 periods the silicon carbide paper was changed. The rubbing surfaces were condnually flushed with distilled water to remove debris. Ten specimens of each of the material samples were tested. Wear was determined by measuring to the nearest 0.05 mm the reduction in length of the specimens by using a light microscope with a calibrated measuring eyepiece. The results were stadstically tested using Wilcoxon's signed-rank test (HAYSLETT& MURPHY 1971).
ABRASIVE WEAR OF RESINS Results
The relative amount of filler particles in the various composite samples is illustrated in Fig. 2. As can be observed the filler content decreased as the degree of dilution was increased. A significant difference (P
