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Biomedical subjects

F Eichmiller

Publications and source records attributed to F Eichmiller.

10 recordsLinked to original sources
PubMed2002

The effect of irradiation wavelength bandwidth and spot size on the scraping depth and temperature rise in composite exposed to an argon laser or a conventional quartz-tungsten-halogen source.

OBJECTIVES: The purpose of this study was to investigate the effect of the spectral distribution of the curing irradiation near the maximum excitation wavelength of the photo-initiator and the effect of the irradiation spot size on the scraping depth-of-cure and temperature rise in a resin composite for both an argon laser and a quartz-tungsten-halogen lamp. METHODS: Using bandpass filters, the spectral outputs of an argon laser and a quartz-tungsten-halogen lamp were restricted to pass selected wavelengths on to a commercial camphorquinone-based resin composite and the depth-of-cure, using scraping methods, was measured. The temperature rise in composite was measured for some of the above-mentioned sources. The spot sizes for both sources were varied and the scraping depth was measured. Lateral curing or the extent of curing away from the focused spot was also measured. RESULTS: For constant power density and exposure time, an irradiation spectral distribution closer to the photo-initiator excitation peak yielded a higher scraping depth than a broadband spectral distribution for both sources. Under similar conditions, the argon laser resulted in a lower temperature rise in the composite than the lamp. For the same total energy imparted to the resin composite, the scraping depth increased with reducing spot size of the curing irradiation. Furthermore lateral curing of the composite well beyond the irradiation spot size was observed. SIGNIFICANCE: The spectral and spatial characteristics of the curing irradiation need to be carefully considered as these affect the scraping depth-of-cure and temperature rise in a resin composite.

Argon↗
PubMed1994

Diagnosis and treatment of an oral base-metal contact lesion following negative dermatologic patch tests.

We report a confirmed case of intraoral contact mucositis secondary to nickel dental alloy hypersensitivity. The lesion resolved after removal of the offending prosthesis. The patient responded negatively to dermatologic patch tests, but a positive intraoral rechallenge confirmed the mucositis diagnosis. A nonreactive, gold alloy prosthesis was inserted for a successful result.

Dental Alloys↗
PubMed1993

The effect of two initiator/stabilizer concentrations in a metal primer on bond strengths of a composite to a base metal alloy.

This study examined the effect of three additives, amine, peroxide and stabilizer, in two concentrations in a metal primer on the adhesion between a cast metal alloy and a resin composite using a 23 factorial statistical design. The additives, benzoylperoxide (BPO) used at 1% or 2% w/w and N,N-dimethyl-p-toluidine (DMPT) at 0.5% or 1.8% w/w are polymerization initiators. The third additive, butylated hydroxytoluene (BHT) at 0.01% or 0.03% w/w, is used as a stabilizer. BPO and BHT were dissolved in an acetone solution containing 20% of the adhesive resin pyromellitic glyceroldimethacrylate (PMGDM). DMPT was in a separate acetone solution. Equal portions of each solution were mixed and applied to a sandpaper-abraded, air-blasted nickel-chrome alloy. Bonding resin and composite were applied over the primer and stored overnight in water. Bond strengths were determined by shearing the composite from the metal at a cross head speed of 0.5 mm/min. Increasing the concentration of BPO caused a statistically significant increase in bond strength. A 3-way analysis of variance (ANOVA) at p<0.05 showed that, of the interactions, only the one between DMPT and BPO was significant, with lower concentrations of DMPT being less sensitive to changes in BPO concentration.

Analysis of Variance↗
PubMed1992

Adhesive properties of modified glass-ionomer cements.

The incorporation of water-soluble polymers and/or vinyl monomers into glass-ionomer cements can yield toughened "hybrid cement-composites". This study compared a commercial water-hardening glass-ionomer cement and seven experimental hybrids in their bonding to both dentin and Silar composite. The cements were sanded and phosphoric-acid-etched or left with an unaltered matrix-formed surface when adhesion to composite was tested. The seven hybrids included: 15% 2-hydroxyethyl methacrylate (HEMA) with appropriate initiators/activators, 29% HEMA, 27% HEMA + 0.5% polyacrylic acid (PAA), 0.5% PAA, 1.5% PAA, 2.5% polyvinyl alcohol, and 2.5% gelatin. Acceptable bond strengths to applied composite and to dentin were observed for most of the modified hybrid cements. There were higher bond strengths with composite when the hybrids were left unetched. Bonding of some unetched, HEMA-containing cements achieved bond strengths (29% HEMA, 10.09 MPa) significantly higher than those of the unmodified cement (4.92 MPa). Resin-modified cements may promote better bonding by improved interaction and compatibility with the resin component of the composite.

Acid Etching, Dental↗
PubMed1992

Effects of aluminum oxalate/glycine pretreatment solutions on dentin permeability.

Aluminum oxalate buffered with glycine to pH 0.5-2.5 has been proposed as a dentin pretreatment for the Gluma bonding system. In this experiment, the effects of 1-minute treatments of smear layers with these aluminum oxalates on the permeability of human dentin were determined in vitro. The aluminum oxalate solutions at pH 0.5-1.5 removed most of the original smear layer but occluded the tubules with crystalline deposits which decreased dentin permeability. Those solutions used at pH 2.0 and 2.5 increased dentin permeability. All dentin pretreatments increased dentin permeability when measured after a 24-hour storage period, especially the solutions at pH 2.0 and 2.5. The SEM correlates of these permeability changes indicated that these solutions remove the smear layer but reocclude the tubules with precipitates which are probably different forms of calcium oxalate, aluminum phosphate and calcium phosphates.

Adult↗
PubMed1991

Effects of ferric and aluminum oxalates on dentin permeability.

The purpose of this study was to compare the efficacy of ferric oxalate, aluminum oxalate, or Tenure dentin conditioner, a marketed product containing aluminum oxalate, at reducing the permeability of human dentin in vitro. Topical treatment with these acidified agents or 2.5% nitric acid for 10, 30, or 60 seconds was compared. The results indicate that 10-second treatments of dentin with all agents increased dentin permeability. Extending the treatment to 30 seconds produced a decrease in dentin permeability for acidified aluminum and ferric oxalate with 60-second treatments being even more effective. Treatment with Tenure dentin conditioner for 60 seconds did not reduce dentin permeability as well as treatment with the other oxalate salts.

Dentin Permeability↗