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.

The relationship of canine-protected occlusion to a periodontal index.

A clinical evaluation was made on 1,000 teeth in 100 patients with Angle's Class I occlusion who were free from histories of orthodontics, removable or fixed prosthesis, occlusal equilibration, maxillary or mandibular jaw fractures, and systemic diseases. The study was made to determine if there was a relation between their patterns of disclusion and a periodontal disease index. In this study, 14% of the subjects exhibited canine protection, 16% a pattern called progressive disclusion, 46% group function, and 24% a different disclusion pattern on each side. The teeth of mouths having canine-protected occlusions had significantly lower mean periodontal disease index scores than the teeth of mouths having progressive disclusion or group function. Also, the canines and the molars in the canine-protected group exhibited lower mean periodontal disease index scores than their counterparts in the progressive disclusion or group function categories.

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.

Light-activated composite resin as an adjunct to the fabrication of fixed partial denture prosthesis.

A technique that permits characterization of provisional restorations with bonding procedures is described. On completion, a glaze of unfilled resin is added to ensure a smooth, nonporous, biologically compatible restoration. Shade tabs are custom stained for dental laboratory use.

A silicone rubber attachment for primary retention of partial dentures.

A technique for primary retention of removable partial dentures has been described. A soft-tissue-borne restoration provides an increase in primary retention without an increase in forces to the abutment teeth, and the restoration requires a minimal outlay of time and money.

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.

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.

The effect of toothbrushing on a hybrid composite resin.

This study observed the effect of various toothpastes on a hybrid composite resin to determine the difference in surface roughness as measured by a profilometer. Slurries (100 gm dentifrice/100 gm H2O) of eight toothpastes were tested by brushing composite resin samples 20,000 times and recording changes in surface smoothness with a profile meter. The surface topography of a hybrid composite resin was altered by routine toothbrushing; the effect of Colgate toothpaste was a statistically smoother surface than found with the other dentifrices; and the surface topography of acrylic resin was altered less by Colgate, Crest, Viadent, and Supersmile than the more abrasive Shane, Sensodyne, Rembrandt, and Topol dentifrices.

Restoration of endodontically treated teeth: a review of the literature.

Once the individual components of the Richmond crown were isolated from the post-core-crown complex, each was subjected to scrutiny. Consensus declared that the core portion should resemble the ideal preparation for a vital tooth. Current techniques allow the dentist to create an "ideal" preparation to accommodate clinical conditions such as occlusion and esthetics. Post construction evaluation can be divided into two categories: retention and stress distribution. Research has demonstrated that threaded posts screwed into tapped post holes were the most retentive, followed by cylindrical posts, and the tapered posts were the least retentive. In photoelastic stress distribution studies, cylindrical posts showed the most favorable patterns, with screw posts demonstrating the least desirable configurations. There is no exclusive technique that satisfies all criteria for success. Compromise is common and the method with more advantages and fewer disadvantages is chosen. Stress distribution is of greater importance than retention because a post can be recemented if dislodged from a tooth. However, if the root fractures, the tooth is commonly lost. Cementation of posts has received limited attention. Some posts with vents are commercially available, but there is little evidence that this effectively decreases hydrostatic pressures during cementation. An important consideration is the choice of materials. Traditionally, pulpless teeth were restored with cast gold posts covered with either complete gold crowns or gold crowns with acrylic resin veneers. These materials had a similar modulus of elasticity and coefficient of thermal expansion.(ABSTRACT TRUNCATED AT 250 WORDS)

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.

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.

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.

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.

Comparison of four techniques for the cementation of posts.

Four techniques for the cementation of cast post restorations were compared in extracted single-rooted teeth. The techniques used were the lentula spiral, endodontic explorer, paper point, and direct post application. Evaluation was based on the presence of voids in the cement and retention of the post. The lentula spiral technique was performed without voids. The other techniques produced voids in increasing numbers in the following order: the endodontic explorer, direct application, and the paper point. The voids were commonly located along the shaft of the post, but there was no correlation between the number of voids and the retention of the posts.

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.