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Biomedical subjects

G R Goldstein

Publications and source records attributed to G R Goldstein.

At least 19 recordsLinked to original sources
PubMed2001

Flavor-spin symmetry estimate of the nucleon tensor charge.

The axial vector and tensor charge, defined as the first moments of the forward nucleon matrix elements of corresponding quark currents, are essential for characterizing the spin structure of the nucleon. There are no definitive theoretical predictions for the tensor charge, aside from several model-dependent calculations. We present a new approach that exploits the approximate mass degeneracy of the light axial vector mesons [ a1(1260), b1(1235), and h1(1170)] and uses pole dominance to calculate the tensor charge. The result is simple in form. It depends on the decay constants of the axial vector mesons and their couplings to the nucleons.

Journal Article↗
PubMed2000

How to evaluate a diagnostic test.

Tests are used in dentistry to establish, confirm, or reject the clinical impression of a diagnosis. Not all tests are equal in their ability to establish a diagnosis, with some tests demonstrating positive results when no disease is present (false positive) or negative results when disease is present (false negative). Using simple mathematical computations, it is possible to determine the extent to which a test can reliably establish the presence or absence of disease. This article describes the concepts of sensitivity, specificity, positive predictive value, negative predictive value, and likelihood ratios through the evaluation of a clinically relevant paper on vital staining for oral carcinoma. This article also describes methods for literature evaluation to determine whether a test conveys meaningful diagnostic information.

Carcinoma↗
PubMed2000

Quantitative sensory nerve conduction threshold (sNCT) evaluation of the trigeminal nerve at the mental foramen area.

STATEMENT OF PROBLEM: There is a need for a quick, objective, quantitative sensory test of the mandibular inferior alveolar nerve to assess sensory dysfunction due to trauma, infection, or disease. PURPOSE: This study evaluated the reliability and reproducibility of a commercially available electrodiagnostic quantitative sensory nerve conduction threshold (sNCT) evaluation testing method and established normative values for future evaluation of nerve dysfunction. MATERIAL AND METHODS: Rapid current perception threshold (R-CPT) values were obtained with Neurometer CPT/C, an electrodiagnostic sNCT device that administers an alternating constant-current sinusoid waveform stimulus at either 2000 Hz (H) (Hertz [cycles/second]), 250 Hz (M), or 5 Hz (L) at intensity levels ranging from 0.001 to 10 mA. Thirty-four healthy subjects were tested then retested by the same operator from 7 days to 153 days. R-CPT evaluation was performed over the mental foramen bilaterally with dual disposable gold-plated electrodes and a hypoallergenic electrode gel held in place using nonconductive adhesive tape. Two consecutive identical R-CPT measures were obtained for each stimulation frequency for determination of the final R-CPT value. RESULTS: On the left side, there was no difference between the first and second test (P > .05). On the right side, there was a statistical difference between the first and second test for L, M, and H, but the confidence interval is very narrow and the differences are not clinically significant. CONCLUSION: From the values obtained, R-CPT testing was reliable for the quantification of sensory function in healthy individuals.

Adult↗
PubMed1996

Effect of two dentinal desensitizing agents on retention of complete cast coping using four cements.

The cementation of artificial crowns is commonly accompanied by sensitivity, so the clinical application of desensitizing agents has become prevalent. This study investigated the effects of Imperva bonding agent and All-Bond desensitizing agent on the retention of artificial crowns. The cements selected for this study were: zinc phosphate, polycarboxylate, glass ionomer, and resin luting agents. Extracted, intact, human molars were mounted in autopolymerizing acrylic resin and prepared for complete cast copings. Thirty-two teeth were treated with All-Bond desensitizing agent, 32 teeth with Imperva bonding agent, and 32 remained untreated. Castings were cemented and tested on an Instron testing machine. The results demonstrated a significant reduction in retention when All-Bond desensitizing agent was used with polycarboxylate cement and some reduction with zinc phosphate cement. Imperva bonding agent demonstrated less retention with glass ionomer cement.

Analysis of Variance↗
PubMed1996

Shear bond strength of several new core materials.

This study compared the shear bond strengths of three core materials: a light activated glass-ionomer cement (VariGlass VLC), a fluoride-release dual cure composite resin (Fluoro Core), and a conventional silver-reinforced glass-ionomer cement (Miracle Mix) when cured to dentin. Fifty-four noncarious molar teeth were extracted, cleaned, mounted in acrylic resin, and sectioned horizontally to expose the dentin surface. Each material was mixed according to manufacturer's instructions, applied in a premade mold to the exposed dentin, and then cured. The specimens were randomized into three group (six teeth from each material) and stored (37 degrees C, 100% humidity) for 15 minutes, 24 hours, and 24 hours and were then thermocycled (5 degrees to 55 degrees C) for 125 cycles. The specimens were tested for shear bond strength with the Instron universal testing machine. The differences among time groups were not statistically significant except for Miracle Mix and VariGlass VLC cements, which showed a greater improvement with thermocycling. This study indicated that the FluoroCore resin exhibited the greatest shear bond strength of the core materials and that VariGlass VLC cement had greater bond strength than Miracle Mix cement except after thermocycling, when VariGlass VLC cement and FluoroCore resin were not significantly different.

Acrylic Resins↗
PubMed1996

The effect of three polishing systems on the surface roughness of four hybrid composites: a profilometric and scanning electron microscopy study.

A highly polished composite restoration is necessary to help promote a plaque-free environment. In this study the polishability of four hybrid composites (Pertac, APH, Herculite, and Z100) was compared after finishing and polishing with the Caulk Enhance polishing kit, Kerr composite finishing kit, and the ESPE MFS/MPS polishing kit. Profilometric evaluation revealed that the MFS/MPS polishing system gave a superior polish for Z100, Herculite, and Pertac; the Enhance polishing system demonstrated the poorest polish with all four composites tested. There were no significant differences among the four composites when polished with each of the three polishing systems.

Analysis of Variance↗
PubMed1995

The effect of dental prophylaxis instruments on the surface roughness of metals used for metal ceramic crowns.

Prophylactic instruments may cause surface deterioration of metal crown margins, which could cause or aid the retention and accumulation of plaque. In this investigation, highly polished metal disks of high content gold (RX Y), low content gold (Aspen), silver palladium (RX 91), and nickel-chrome alloy (REX III) had their surfaces tracked with an explorer, hand scaler, curette, and a Dentsply Cavitron instrument. The surface roughness was measured with a profilometer. The results indicate that the high content gold was the least resistant to surface deterioration and the ultrasonic scaler caused the most surface deterioration to all the metals.

Analysis of Variance↗
PubMed1995

Enamel wear caused by three different restorative materials.

The ideal restorative material should cause minimal wear of opposing enamel. This study compared the effects of gold alloy, glazed porcelain, and a laboratory-processed composite on opposing enamel. Ten samples of a type III gold alloy, a porcelain, and a visible-light, heat, and vacuum-processed composite were abraded against cusps of extracted molars for 10,000 cycles on an abrading machine. Pretest and posttest profilometric measurements of the restorative materials demonstrated no statistical difference. Pretest and posttest tracings of the cusps were made on an optical comparator to determine loss of vertical height and surface area. The porcelain caused significantly more loss of vertical height and surface area than the gold alloy or the composite, which were similar.

Analysis of Variance↗
PubMed1995

A survey of temporomandibular disorder conducted by the Greater New York Academy of Prosthodontics.

The results of a temporomandibular joint survey sent to 167 members of the Greater New York Academy of Prosthodontics indicated a great variation in the diagnosis and treatment of patients with temporomandibular joint dysfunction. Although most indicated that their background in temporomandibular joint disorders was from clinical experience and/or textbooks and the dental literature, only 59% treated patients for these disorders. The most common diagnostic procedures were occlusal evaluation; joint evaluation for tenderness, crepitus, and click; evaluation of range of motion of the mandible; and a muscular evaluation. Only 35% used a formal temporomandibular joint dysfunction questionnaire. The percentage of complete denture patients with these symptoms was 5% or less. Thirty-three percent of clinicians sometimes treated asymptomatic patients who were without pain but had a click. Two thirds of the respondents believed that surgery was sometimes indicated for disk degeneration and displacement. More recent graduates are more likely to treat patients who have temporomandibular joint dysfunction than are older more experienced practitioners.

Attitude of Health Personnel↗
PubMed1994

A comparison of the diametral tensile strength, the flexural strength, and the compressive strength of two new core materials to a silver alloy-reinforced glass-ionomer material.

This study compared three mechanical properties of two recently introduced core materials, a light-activated glass ionomer cement (VariGlass VLC) and a fluoride-release dual cure composite resin (FluoroCore), with those of a conventional silver-reinforced glass-ionomer cement (Miracle Mix). Seventy-two samples (eight per product for each property) were prepared for testing diametral tensile strength, flexural strength, and compressive strength. The specimens were cured, stored for 24 hours at 37 degrees C in 100% humidity, and tested with the use of an Instron universal testing machine. The results of this study indicate that the diametral tensile strength, flexural strength, and compressive strength of the FluoroCore and VariGlass VLC materials were significantly higher than those of the conventional Miracle Mix. The values obtained with FluoroCore material were consistently higher than those obtained with VariGlass VLC material.

Acrylic Resins↗
PubMed1994

Effectiveness of a professional formula disinfectant for irreversible hydrocolloid.

In this study, the effectiveness of Professional Lysol (PL) disinfectant in both its spray and solution forms was evaluated as a surface disinfectant for irreversible hydrocolloid (IH) impressions. Sixteen impressions of a typodont were made with IH, immersed in a microbial broth, and then rinsed in running tap water. The impressions were then treated as follows: four were immersed in PL for 2.5 minutes; four were sprayed by PL and stored for 10 minutes; four were immersed in 2% glutaraldehyde for 10 minutes; four were untreated. Pretest plates showed an average of 421 colonies per plate (c/p). The glutaraldehyde group showed 0.00 c/p. The PL spray group showed 1.75 c/p. The PL immersion group showed 19.00 c/p and showed evidence of surface deterioration in the IH. The untreated group showed 426.25 c/p.

Aerosols↗
PubMed1993

Bleaching: is it safe and effective?

It has been well documented that bleaching whitens teeth, but has its safety been documented? This paper reviews bleaching's predictability, esthetics, longevity, and side effects. A discussion of the bleaching reaction on teeth and soft tissue raises concerns over the safety of the procedure.

American Dental Association↗
PubMed1993

Repeatability of a specially designed intraoral colorimeter.

A specially modified Minolta CS-100 colorimeter with a DP-101 data processor was designed for intraoral use. To test the repeatability of the results obtained with this specially modified unit, five porcelain and five acrylic resin denture teeth were mounted in a fixed position in front of a fixed mounted meter. Three L*a*b* readings were taken per tooth and mean values were obtained after calibration as a baseline measurement. The readings were repeated on day 3 without recalibration and on day 8 after recalibration. The same-day repeatability showed delta E values < 0.4 in nine of the 10 samples. The day 3 repeatability showed delta E values < 0.4 in only 2 of the 10 samples. The day 8 results, after recalibration, showed delta E values > 0.4 in all of the samples, with a range of 0.57 to 2.75. In vivo testing was performed on five patients with delta E values that ranged from 1.1 to 32.1.

Acrylic Resins↗
PubMed1992

Flexion characteristics of four-unit fixed partial denture frameworks using holographic interferometry.

Flexion of a metal/ceramic fixed partial denture (FPD) framework under function can cause fracture of the porcelain or deterioration of the cement seal. This study evaluated the flexion under compressive load of a four-unit mandibular FPD replacing the second premolar and the first molar. Testing was accomplished with elapsed time holographic interferometry, using 39 porcelain fused-to-metal frameworks cast with a silver-palladium alloy. The results demonstrated that solder joints at the junction of the premolar and molar pontics flexed under a reduced compressive load and exhibited a higher failure rate than other connector designs.

Analysis of Variance↗
PubMed1992

An alternative immediate complete denture impression technique.

An alternative immediate denture impression technique for extremely mobile teeth, utilizing amalgam condensers, has been presented. The apically applied pressure on the mobile teeth minimizes the risk of accidental tooth extraction during impression removal.

Alginates↗
PubMed1992

Survey of post procedures.

Methods used to restore endodontically treated teeth have changed over the last few years. The traditional standard of using a cast-gold post and core for all endodontically treated teeth has been questioned in the literature. The following is a report of a survey that the authors conducted to determine if there is a discrepancy between research and clinical practice.

Acid Etching, Dental↗
PubMed1991

Profilometer, SEM, and visual assessment of porcelain polishing methods.

Research has indicated that polishing ground porcelain is essential to control the wear of opposing occlusal surfaces and reduce the inflammation of contacted soft tissue. Five popular methods for polishing porcelain were evaluated by use of a profilometer, SEM, and normal vision. Seventy disks, 35 Biobond disks and 35 Ceramco disks, were roughened with a green stone and polished with one of the methods according to the manufacturers' directions. Brasseler, Dedeco, Dentsply, and Shofu porcelain polishing systems were suitable for restoring ground porcelain. However, clinical evaluations correlated to the profilometer and SEM readings revealed that the Brasseler system was superior for polishing Ceramco porcelain whereas the Den-Mat system was unacceptable.

Analysis of Variance↗