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Biomedical subjects

E F Huget

Publications and source records attributed to E F Huget.

At least 19 recordsLinked to original sources
PubMed2001

Accelerated color change in a maxillofacial elastomer with and without pigmentation.

STATEMENT OF PROBLEM: Maxillofacial prostheses require frequent replacement because the elastomer and its color additives undergo changes. PURPOSE: This study attempted to determine whether predictable color changes occur when 3 pigments are individually incorporated into a specific silicone elastomer. MATERIAL AND METHODS: The materials included an RTV elastomer; 1 natural inorganic pigment, burnt sienna; and 2 synthetic organic pigments, Hansa yellow and alizarin red. Eight test groups of 10 polymerized specimens were established. Groups 1 and 2, acting as the control, involved only the elastomer. Groups 3 and 4 were composed of elastomer and burnt sienna. Groups 5 and 6 consisted of elastomer and Hansa yellow. Groups 7 and 8 comprised elastomer and alizarin red. Odd-numbered groups were assigned to a test site in Miami, Fla., whereas the even numbered groups went to Phoenix, Ariz. Specimens weathered in Miami and Phoenix received sunlight exposures of 1305.7 MJ/m2 and 1310.2 MJ/m2, respectively, over time. Before and after weathering, the L* a* b* color parameter (DeltaE*) of each specimen was determined spectrophotometrically. RESULTS: Mean color changes that occurred in Arizona were larger than those produced in Florida. Specifically, these differences ranged from 0.4 (alizarin red groups) to 2.36 units for the 2 unpigmented control groups. Other differences showed significance for the unpigmented (P=.001), burnt sienna (P=.006), and Hansa yellow groups (P=.001). CONCLUSION: Outdoor weathering tests in which documented ASTM methods were used provided a valid baseline for future research on color changes in maxillofacial prostheses.

Analysis of Variance↗
PubMed2000

Periodic evaluation of the occlusal vertical dimension of maxillary dentures from the wax trial denture through 48 hours after polymerization.

PURPOSE: This study measured the effects of commercial resin type on maxillary complete dentures with monoplane teeth by periodically comparing the occlusal vertical dimension of the polymerized dentures with the baseline, wax trial denture fiducial measurements. MATERIALS AND METHODS: Commercially available compression-molded, injection-molded, and fluid poly(methyl methacrylate) resins, as well as one compression-molded methyl acrylate ester copolymer, were evaluated. Ten dentures were fabricated from each resin using monoplane teeth. The occlusal vertical dimension at the articulator pin was measured at the wax denture stage for each specimen, and changes in occlusal vertical dimension for each denture were evaluated at a simulated laboratory remount, and at 0, 3, 6, 24, and 48 hours after a simulated clinical remount. Repeated measures analysis of variance (alpha = 0.05) and post hoc one-way factorial analysis of variance and Scheffe's F-Tests for each resin group were performed using ranks of raw data. RESULTS: Changes in the maxillary denture mean occlusal vertical dimensions were recognized throughout the evaluation periods compared with the wax-denture baseline, and time was a significant influence on displacement (p = .0001). Only the compression-molded poly(methyl methacrylate) dentures exhibited a mean laboratory remount occlusal vertical dimension that was significantly greater than the mean wax denture measurement, and all resin systems exhibited occlusal error that was significantly less than the laboratory remount measurements at 48 hours. At 48 hours, all resin groups exhibited mean occlusal vertical dimension changes that were less than 1 mm compared with the wax denture. Only compression-molded poly(methyl methacrylate) dentures exhibited a mean 48-hour clinical remount measurement that was statistically similar to the mean wax denture occlusal vertical dimension. CONCLUSIONS: Individual maxillary dentures from all resin types and at all intervals exhibited dimensional change. At the last evaluation period, the compression-molded poly(methyl methacrylate) showed no change in mean occlusal vertical dimension from baseline, whereas remaining groups exhibited occlusal vertical dimensions significantly less than baseline.

Acrylates↗
PubMed1999

Resin composites for foundation restorations.

This study focused on the compressive properties of two core buildup materials, Ti-Core, (EDS, Inc.) and FluoroCore, (L.D. Caulk). Specimens were 0.6 x 1.2 cm cylinders, Prior to testing, the specimens were aged in a moist environment for one, seven, or 28 day(s). The properties of interest were compressive strength, modulus of elasticity and toughness. The data set for each of the three compressive properties was subjected to a separate two-way analysis of variance. Scheffé F-tests were used to compare means. Whereas the effect of material on each of the three properties was significant (p < 0.002), the effects of specimen age (p > 0.400) and material x specimen age (p > 0.350) were not significant. FluoroCore was stronger and tougher than Ti-Core. On the other hand, Ti-Core displayed the highest stiffness, but ruptured brittley. The moderately low strength of Ti-Core, and the insufficient elastic modulus of FluoroCore, avert favorable recommendations pertaining to the construction of foundation restorations.

Analysis of Variance↗
PubMed1998

Compressive properties of chemically cured, resin modified glass ionomer luting cements.

This study compared the responses of three proprietary chemically cured hybrid glass ionomer luting cements to compressive loading. These cements bear the trade names Advance, Fuji DUET and Vitremer Luting Cement, and are distributed and sold through ordinary domestic and international channels of dental commerce. The findings are as follows: 1. Advance, and Fuji DUET were stronger and stiffer than Vitremer Luting Cement. On the other hand, Vitremer exhibited the highest toughness. 2. The compressive properties of Advance were not affected significantly by increasing the specimen aging period to 28 days from seven days. 3. Prolonged aging of Fuji DUET and Vitremer specimens in a humid environment elicited significant changes in compressive strength and modulus of elasticity. Whereas the strength and elastic modulus changes for Fuji DUET were negative, the changes experienced by Vitremer were positive. 4. Extending the specimen aging period to 28 days from seven days did not affect significantly the toughness of either Fuji DUET or Vitremer Luting Cement. Relatively low elastic moduli limit the application of the chemically cured hybrid glass ionomers to the cementation of one- to three-unit cast fixed restorations.

Analysis of Variance↗
PubMed1997

Wear of visible light-cured restorative materials and removable partial denture direct retainers.

PURPOSE: This study measured the in vitro wear of visible light-cured restorative materials and removable partial denture direct retainers. MATERIALS AND METHODS: An aluminum test die was produced by replicating the facial contours of an extracted human molar (model). The replica's cervical contour was modified by placement of a restorable Class V cavity preparation. The test die became a fixed component of a testing apparatus. The restorative materials tested were Z100 (fine particle filled resin composite), Silux Plus (microfilled resin composite), and Photac-Fil (hybrid glass ionomer). Cast round, half round, I bar, and wrought-wire retainers were designed to engage a 0.254-mm undercut. Caliper measurements of the wear of restorative materials were made at intervals during testing, and after 7,500 retainer placements and removals. The measurements of material- and retainer-wear were subjected to ANOVA and Tukey tests. RESULTS: Generally, retainers with round profiles caused less wear of the restorative materials than those featuring flat contact surfaces. Wear of the materials ranged from 14 +/- 5.5 microns (Silux Plus by cast round) to 70 +/- 10.0 microns (Photac-Fil by cast half round). Mean wear of retainers, however, ranged only from 2 +/- 4.5 microns for six of 12 possible retainer-material pairings up to 12 +/- 4.5 microns (cast half round by Z100). CONCLUSIONS: Regardless of their design features, the direct retainers of this study exhibited little wear when paired with any of the restorative materials. Overall, material wear appeared to be greater than retainer wear by a factor of five. When paired with practically any retainer type, the hybrid glass ionomer (Photac-Fil) exhibited more wear than either of the two resin composites (Z100 or Silux Plus). Although not established clearly, retainers with round profiles (wrought-wire and cast round) appeared to produce less wear of restorative materials than their I bar and cast half round counterparts.

Analysis of Variance↗
PubMed1996

The effect of etchant and cement age on the adhesion of resin composite to conventional and resin-modified glass-ionomer cements.

The effects of etching with maleic or phosphoric acid on the adhesion of resin composite to resin-modified glass-ionomer cement restorative materials were evaluated through a shear bond test. These effects were determined with both recently set and aged cement. For the three resin-modified materials tested, compared to no etching, the two etchants improved or did not affect the adhesion of resin composite, regardless of the age of the cement. For a chemically cured material, included in the study as a control, the same effects were observed, except that etching of the recently set cement with maleic acid was detrimental to adhesion.

Acid Etching, Dental↗
PubMed1990

Apparent density and tensile strength of materials for facially butted porcelain margins.

The study focused on comparison of the as-fired density and tensile strength of unmodified and modified porcelains used for construction of facially butted porcelain margins. The respective densities and tensile strengths of unmodified body and shoulder porcelains were found to be comparable. Also statistically equivalent were the measured properties of specimens made from either an unmodified shoulder-porcelain formulation or shoulder-porcelain powder--aqueous sodium silicate solution mixtures. On the other hand, the respective densities and tensile strengths of body porcelain-resin and shoulder porcelain-wax combinations were significantly lower (p less than 0.05) than those of their unmodified counterparts. Low density and tensile strength limit the rational use of wax or resin-modified porcelains to final bakes for correcting small, troublesome labiogingival discrepancies.

Analysis of Variance↗
PubMed1990

Observations on the elastic behavior of a synthetic orthodontic elastomer.

The study focused on changes in elasticity that accompany water storage of a synthetic orthodontic elastomer. We plotted loading and unloading curves to permit the direct measurement of instantaneous elastic recovery (IER) and permanent set (PS) and the calculation of delayed recovery (DR). We obtained baseline data by testing dry as received material. Comparable tests were performed on material that had been stored in water at 37 degrees C for one, seven, 14, 42, and 70 days. Gas chromatography-mass spectrometry was used for analysis of organic substances leached from the elastomer by water. A two-way ANOVA revealed that extension distance and water storage duration affected load requirement, IER, PS, and DR. The presence of leachable organic substances in 14-, 42-, and 70-day storage water was evidence of time-dependent matrix decomposition. Findings from tests of elastic performance and analysis of specimen storage water indicate that exposure of the elastomer to water leads first to weakening of noncovalent forces and subsequently to degradation.

Analysis of Variance↗
PubMed1983

The effects of die relief agent on the retention of full coverage castings.

The effect of a commercial die relief agent on the retention of castings cemented with a zinc phosphate, a zinc polycarboxylate, or a modified zinc oxide-eugenol cement was studied. Forces required to dislodge unspaced castings from tooth preparations were higher when zinc phosphate cement was the luting medium. Die relief agents resulted in a 32% reduction in the forces required to dislodge castings cemented with zinc phosphate. Data for the other cements did not differ statistically. Shear strength-tensile ratios of the cements indicate that the high shear strength provided by zinc phosphate cement may be negated by the cementation of oversize castings fabricated from relieved dies.

Crowns↗
PubMed1980

Observatons on gold-palladium-silver and gold-palladium alloys.

Properties, heat treatment response, structure, and composition of three high-fusing crown and fixed partial denture alloys were studied. Except for elongation, the properties of two gold-palladium-silver based materials were compared to those of a gold-palladium alloy. The greater elongation of the latter material was attributed to its intragranular homogeneity.

Chemical Phenomena↗
PubMed1980

Apparent viscosities of setting elastomers.

The flow behavior of five elastomeric impression materials was determined by extrusion viscometry. Initial viscosity ranged from 400 to 5,100 poise at a shear rate of 2.2 reciprocal seconds. All of the elastomers showed initial non-Newtonian behavior and increased viscosity with time.

Dental Impression Materials↗