Effect of prophylactic polishing protocols on the surface roughness of esthetic restorative materials.

Many polishing protocols have been evaluated in vitro for their effect on the surface roughness of restorative materials. These results have been useful in establishing protocols for in vivo application. However, limited research has focused on the subsequent care and maintenance of esthetic restorations following their placement. This investigation evaluated the effect of five polishing protocols that could be implemented at recall on the surface roughness of five direct esthetic restorative materials. Specimens (n=25) measuring 8 mm diameter x 3 mm thick were fabricated in an acrylic mold using five light-cured resin-based materials (hybrid composite, microfilled composite, packable composite, compomer and resin-modified glass ionomer). After photopolymerization, all specimens were polished with Sof-Lex Disks to produce an initial (baseline) surface finish. All specimens were then polished with one of five prophylactic protocols (Butler medium paste, Butler coarse paste, OneGloss, SuperBuff or OneGloss & SuperBuff). The average surface roughness of each treated specimen was determined from three measurements with a profilometer (Surface 1). Next, all specimens were brushed 60,000 times at 1.5 Hz using a brush-head force of 2 N on a Manly V-8 cross-brushing machine in a 50:50 (w/w) slurry of toothpaste and water. The surface roughness of each specimen was measured after brushing (Surface 2) followed by re-polishing with one of five protocols, then final surface roughness values were determined (Surface 3). The data were analyzed using repeated measures ANOVA. Significant differences (p=0.05) in surface roughness were observed among restorative materials and polishing protocols. The microfilled and hybrid resin composite yielded significantly rougher surfaces than the other three materials following tooth brushing. Prophylactic polishing protocols can be used to restore a smooth surface on resin-based esthetic restorative materials following simulated tooth brushing.

Effect of finishing and polishing procedures on the surface roughness of packable composites.

This study examined the average surface roughness (Ra, micron) of three packable composites and one hybrid composite cured against mylar, before and after treatment with a fine finishing diamond bur, a resin finisher followed by fine and extrafine polishing paste, two silicone-based finishing and polishing systems, fine and super-fine aluminum-oxide polishing disks, a silicon carbide-impregnated polishing brush and a surface-penetrating composite sealant. Additionally, the Ra was examined for one of the packable composites before and after treatment with a finishing carbide, prior to the finishing and polishing procedures detailed above. The finishing diamond significantly increased the Ra for all composites (ALERT, SureFil, Solitaire and Z-100). The finishing carbide used with SureFil (SureFil + C) also increased the Ra; however, it also produced surfaces up to 3.5x smoother when compared to SureFil surfaces finished with the diamond. Overall, Sof-Lex Contouring and Polishing Discs were able to produce the smoothest surfaces, followed by the Jiffy Composite Polishing Cups, the Enhance Composite Finishing & Polishing System/Prisma-Gloss Composite Polishing Paste, the Diacomp Intra-Oral Composite Polishers and the Jiffy Composite Polishing Brushes, respectively. The smoothest surfaces were produced using Z-100, followed by SureFil + C (carbide finishing bur), Solitaire, SureFil and ALERT, respectively. In general, Protect-It Composite Surface Sealant had little effect on the Ra, except with ALERT, where a slight increase in Ra was observed.

Bond strength of composite to air-abraded enamel and dentin.

Human enamel and dentin were prepared with an air abrasion unit (KCP-2000), using two particle sizes (27 micrometers and 50 micrometers) of aluminum oxide. In vitro tensile bond strengths of a composite resin were determined after three enamel and three dentin surface treatments. Enamel treatments were: air abraded only, E-1; air abraded + adhesive, E-2; air abraded + acid etch + adhesive, E-3. Dentin surface treatments were air abraded only, D-1; air abraded + adhesive/no primer, D-2; air abraded + primer + adhesive, D-3. Etched enamel and dentin prepared with 600-grit SiC paper and adhesive served as controls. There were 10 replications for each condition. A dentin bonding system (Optibond) and a composite resin (Herculite XRV) were bonded to treated surfaces by light curing in an inverted, truncated cone die with a bond diameter of 3 mm. Samples were stored at 37 degrees C and 100% relative humidity for 24 hours and debonded in tension using a Universal Testing Machine at a 0.05 cm/min crosshead speed. Based on analysis of variance, there was no statistical difference between 27 micrometers and 50 micrometers aluminum oxide abrasive for both enamel and dentin. For enamel bond strengths, E-2 was significantly higher than E-1, and E-3 was significantly higher than E-1 and E-2. E-1 and E-2 were significantly lower than the control, while E-3 was not significantly different from the control (P < or = 0.05). For dentin bond strengths, D-2 was significantly higher than D-1, and D-3 was significantly higher than D-1 and D-2. All treatments except D-3 were significantly lower than the control (P < or = 0.05). Air-abrasion treatment of enamel and dentin alone resulted in reduced in vitro bond strengths as compared to etched enamel and dentin prepared with dentin adhesive and dentin primer.

In vitro bond strength of repaired amalgam with adhesive bonding systems.

The in vitro tensile bond strengths of Amalgambond and All-Bond were evaluated as adhesive systems for the repair of amalgam (Valiant Ph.D.) by two repair amalgams (Valiant or Valiant Ph.D.). Other variables evaluated were two surface finishes (SiC finish and sandblasted) and two storage conditions (37 degrees C, 24 h, and thermocycled). The Amalgambond bond was not reliable. All-Bond bonded amalgam to amalgam with Liner-FX. Bond strengths ranged from 3.4 to 8.8 MPa. The highest bond strengths were achieved with a sandblasted surface repaired with Valiant. Thermocycling did not affect bond strength.

Bond strength of repaired glass ionomer core materials.

Chelon Silver (C), Ketac-Silver Aplicap (K), Miracle Mix (M) silver-reinforced glass ionomers, and Valiant PH.D were evaluated as in vitro repair materials for cores. The core materials were placed in a 6 x 3 mm mold and stored at 37 degrees C at 100% RH for 24 hours. The cores were roughened with a coarse diamond. Five samples were conditioned (T) with Dentin Conditioner for 20 seconds, whereas another 5 samples were untreated (U). The cores were then repaired with C, K and M and subsequently tested after additional storage for 24 hours. Bond strength (MN/m2) was measured in tension using an inverted cone bond test at a crosshead speed of 0.05 cm/min. Mean bond strengths (S.D.) for the three repair materials when averaged over the three glass ionomer cores were: K, 5.0 (1.2); M, 3.4 (1.2) and C, 2.7 (1.5) for condition U; and M, 4.2 (1.1); K, 3.4 (1.2); and C, 3.1 (1.0) for condition T, where M, K and C were the repair materials. The Tukey intervals at the 95% level were 0.7 among materials and 0.5 between treatments. Bond strength of repaired amalgam was only successful with M, 0.9 MN/m2. Bond strengths to untreated silver-reinforced glass ionomer cores were higher with K used as a repair material.