Surface Roughness of Methacrylate- and Silorane-Based Composites After Finishing and Polishing Procedures.

OBJECTIVE: To compare the effect of surface finishing and polishing protocols on the surface roughness (Ra) of methacrylate-based and silorane-based resin composites. METHODS AND MATERIALS: Fifty specimens (5 mm x 2 mm) of each composite material were prepared using a split mold: Filtek™ Supreme Ultra (3M ESPE), Tetric EvoCeram® (Ivoclar Vivadent), Tetric Ceram™ HB (Ivoclar Vivadent), and Filtek™ LS Low Shrink (3M ESPE). Specimens were divided into five groups (n = 10) according to the following procedures: G1 - 15-µm fine diamond bur (FDB); G2 - 15-µm FDB followed by a 20-fluted tungsten carbide bur; G3 - 15-µm FDB followed by diamond-impregnated micropolishing points (D-FINE Double Diamond Polishing System, Clinician's Choice); G4 - 15-µm FDB followed by diamond-impregnated micropolishing points (Flame Point Pre-polisher and Shine, Brassseler USA); and G5 - 15-µm FDB followed by the application of a surface sealer (PermaSeal®, Ultradent Products, Inc.). Ra was measured in three different regions using a surface profilometer (Mitutoyo Surfest SJ-210, Mitutoyo America). RESULTS: Multiple comparisons were obtained using a one-way ANOVA with Tukey's B rank order test ( = 0.05). No significant differences in Ra were observed among the resin composites tested in the same condition. The use of a FDB generated the highest roughness values, while the use of a surface sealer resulted in the lowest roughness values for all resin composites tested (P < .05). No significant difference in Ra was observed between the use of a multi-fluted carbide bur and the rubber point D-FINE Double Diamond Polishing System for all resin composites tested.

Quality and Conservative Approach to Class I Resin Composite Restorations.

Advances in technology and adhesive dentistry have allowed practitioners to achieve long-term restorative results with minimal damage to tooth structures. The use of bonded restorations in restorative dentistry, including placement of resin composite restorations, has largely replaced the use of amalgam. The clinical case presented describes a technique utilizing minimal cavity preparation aimed at improving the quality and longevity of a Class I resin composite restoration. The procedure includes the use of an occlusal index to restore the tooth back to its original contour and anatomy. Other factors discussed are the use of MMP inhibitors, new advances in bonding agents, proper light-curing technique, and minimal finishing and polishing of the restoration.

Effect of surface treatments on the bond strength of self-etching adhesive agents to dentin.

The aim of this study was to investigate the influence of different surface treatments on the shear bond strength (SBS) of self-etching adhesive systems to dentin. Ninety freshly extracted noncarious human molars were sectioned mesiodistally and embedded in chemically cured resin with the buccal or lingual surfaces facing upward. Superficial dentin was exposed, and specimens were randomly assigned to 3 groups, according to the self-etching adhesive system utilized: Clearfil SE Bond (2-step), Scotchbond Universal (1-step), and Clearfil S³ Bond Plus (1-step). These groups were assigned to 5 subgroups (n = 12), according to the following treatments: G1, distilled water (control); G2, 35% phosphoric acid gel; G3, ultrasonic vibration; G4, sandblasting; G5, pumice slurry. For the 1-step self-etching adhesives, no significant differences in SBS values were observed between the different surface treatment groups and their control subgroup (P > 0.05). For the 2-step adhesive, mean values were significantly higher in the ultrasonic vibration and pumice-treated groups than in the control subgroup (P < 0.05). Overall, the use of vibration resulted in superior mean SBS values to dentin for all adhesives tested, although the values were not always significantly higher.

Effect of Finishing Procedures on the Surface Roughness of Resin-modified Glass-Ionomer Materials.

This study examined the influence of finishing procedures on the surface roughness of different formulations of resin-modified glass ionomers (RMGIs) available in capsules compared with standard resin composites (RCs). Disc samples of three RMGIs and two RCs were fabricated using a metal mold (5 mm x 1.5 mm). Samples were randomly divided into seven groups (N = 10) and subjected to finishing and polishing procedures using a combination of carbide or diamond burs, followed by either rubber points or aluminum-oxide discs. Three different regions of each sample were analyzed using a contact profilometer to determine the average roughness (Ra). The main surface roughness was calculated using a two-way analysis of variance (ANOVA) and the Bonferroni correction for multiple comparisons. A dual-stage combination of a fine carbide bur followed by the use of the finest two grits of aluminum-oxide discs was found to produce the smoothest finished and polished surface. the smoothest surfaces were found to be on the two RCs and one of the RMGIs.

Effect of artificial aging on the surface roughness and microhardness of resin-based materials.

This study sought to verify the effects of aging on the surface roughness (Ra) and microhardness (Knoop hardness number [KHN]) of resin-based restorative materials protected with a surface sealer. Disc specimens of 2 resin-modified glass ionomers (RMGIs) and 1 composite resin (CR) were fabricated in a metal mold. Specimens of each material were divided into 1 group that was covered with surface sealer and 1 group that was not. Both groups of each material were then subdivided according to whether they were stored (aged) in cola or distilled water. Surface roughness and KHN values were obtained from each specimen before and after storage. After aging of the specimens, significantly higher Ra values were observed in the 2 RMGIs when they were not covered with a surface sealer, while the CR was not affected. The KHN values varied by materials and storage conditions (with and without a surface sealer). All the groups with a surface sealer exhibited increased Ra values after aging.

Clinical evaluation of silorane-based and dimethacrylate-based resin composites: 1-year follow-up.

This study sought to evaluate the 1-year clinical performance of silorane-based and dimethacrylate-based Class II resin composite restorations using 2 bonding strategies. Eighty-two restorations were placed in 32 patients (median age 37 years) by a single operator. Only Class II restorations were included. Each patient received 1-2 pairs of resin composite restorations with both restoration materials. Between-group comparisons were made using an adjusted chi-square test and an adjusted McNemar's chi-square test to analyze the intrasystem data (α = 0.05). Both systems demonstrated acceptable clinical performance after 1 year.

Effect of preheating on microhardness and viscosity of 4 resin composites.

OBJECTIVE: This study was undertaken to determine the effect of temperature on the microhardness and viscosity of 4 resin composite materials. METHODS: To investigate microhardness, samples of each of the 4 composite materials, prepared by standard insertion of resin into prefabricated moulds, were divided into 2 groups (n = 10 per group). On the first group, the resin composite materials were inserted into the moulds at room temperature and cured. On the second group, the resin composite materials were pre-heated in a heating device, inserted into the moulds and immediately cured. Microhardness after curing (both immediately and after 24 hours of storage) was determined (using a 300 g load applied for 10 seconds) and averaged for 5 randomly selected points on the top and bottom surfaces of each sample. To investigate viscosity, 0.5 g samples of room temperature or preheated resin composite (n = 15 per group) were placed under a 454 g load for 45 seconds before light-curing (40 seconds). After curing, each sample was photographed and the surface area calculated. Data were analyzed by t tests or one-way analysis of variance and Tukey's test. RESULTS: Preheating the resin composites increased the microhardness and decreased the viscosity of the samples. Filtek Supreme Ultra resin composite had the highest mean microhardness, and Vit-l-escence resin composite had the lowest viscosity. CONCLUSIONS: The effects of preheating resin composites may allow easier placement of restorations and greater monomer conversion.