Gary R. Goldstein

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.

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.

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.

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.

Bleaching: Is it safe and effective?

It has been well documented that bleaching whitens teeth, but has its safety been documented? This paper reviews bleachings 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.

Comparison of the Marginal Fit of Pressable Ceramic to Metal Ceramic Restorations

PURPOSE The aim of this in vitro study was to compare the marginal adaptation of a pressed ceramic material, when used with and without a metal substructure, to a traditional feldspathic porcelain-fused-to-metal restoration with a porcelain butt margin. MATERIALS AND METHODS A maxillary central incisor typodont tooth was prepared with a 1.5 mm 360 degrees shoulder with rounded internal line angle, and 30 polyether impressions were made. Dies were poured in type IV dental stone, and 30 restorations were fabricated: 10 metal ceramic restorations (MCR) with porcelain butt joints, 10 pressed to metal restorations (PTM), and 10 all-ceramic restorations (PCR). All restorations were evaluated on their respective dies at 45x magnification using an Olympus SZX-12, measurements of the marginal openings were made, and ANOVA and Scheffé post hoc tests were used to evaluate the data. RESULTS The mean marginal opening was 72.2 +/- 5.9 microm for MCR, 49.0 +/- 5.9 microm for PTM, and 55.8 +/- 5.9 microm for PCR. The post hoc tests showed that there was a statistical difference between the marginal adaptation of the PTM and MCR groups (p < 0.05). There was no significant difference in marginal adaptation between the PTM and the PCR groups, or the PCR and the MCR groups. CONCLUSIONS The PTM group demonstrated a smaller mean marginal opening than the MCR group. The mean marginal openings of all three groups were within a clinically acceptable range.

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

A clinical evaluation was made on 1,000 teeth in 100 patients with Angles 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 in vitro comparison of tensile bond strengths of noble and base metal alloys to enamel.

STATEMENT OF PURPOSE Many different surface treatments have been used to increase the bond strength of noble and base metal alloys to enamel, but only a few have been studied. PURPOSE The purpose of this in vitro study was to compare the tensile bond strength of a tin-plated noble alloy, an Alloy Primer-treated noble alloy, and an airborne particle-abraded base metal alloy, all bonded to enamel with a phosphate-methacrylate resin luting agent. MATERIAL AND METHODS Seventy noncarious molar teeth were extracted, cleaned, and embedded in autopolymerizing acrylic resin with the buccal surface of the teeth exposed. Seventy wax patterns (4-mm diameter x 2-mm thickness) were waxed, invested, and cast-50 with a noble alloy (Argedent 52) and 20 with a base metal alloy (Argeloy N.P.). Twenty of the noble alloy specimens were tin-plated (TP), 20 noble alloy specimens were treated with Alloy Primer (AP), and 20 base metal alloy specimens were airborne particle abraded (AA). All specimens were luted with a phosphate-methacrylate resin luting agent (Panavia F) and stored in 100% humidity at 37 degrees C, half for 24 hours and half for 7 days. Ten noble alloy specimens were tin-plated and stored in water for 48 hours (aged) before cementation and then stored in water for 24 hours after cementation. These specimens were used to test whether there is an advantage to aging the tin-plated surface in water before cementation. All specimens were thermocycled (5 degrees to 55 degrees C) for 500 cycles and then tested for tensile bond strength (TBS), measured in MPa, with a universal testing machine at a crosshead speed of 0.5mm/min. Various castings (n=6 per test group) were randomly selected from each group and inspected under a scanning electronic microscope to determine mode of failure. The mean values and standard deviations of all specimens were calculated for each group. A 2-way analysis of variance (ANOVA) was performed, and multiple pairwise comparisons were then completed with post hoc Tukey test (alpha=.05). RESULTS The TBS of the tin-plated noble alloy specimens bonded to enamel (24 hours: 9.33 +/- 1.31 MPa; 7 days: 11.65 +/- 1.55 MPa) was significantly greater than the Alloy Primer noble alloy specimens (24 hours: 6.11 +/- 1.01 MPa; 7 days: 5.45 +/- 1.22 MPa) (P <.001). The Alloy Primer noble alloy group showed the lowest TBS compared with the tin-plated noble alloy and airborne particle-abraded base metal alloy group (24 hours: 10.61 +/- 1.41 MPa; 7 days: 6.94 +/- 1.40 MPa). The tin-plated noble alloy specimens showed greater TBS after storage for 7 days in distilled water compared with storage for 24 hours (24 hours: 9.33 +/- 1.31 MPa; 7 days: 11.65 +/- 1.55 MPa). Aging the tin-plated noble alloy for 48 hours in 37 degrees C (9.17 +/- 1.68 MPa) prior to cementation did not increase the TBS to enamel. The airborne particle-abraded base metal alloy showed significantly lower TBS at the 7-day storage time compared to the 24-hour storage time (24 hours: 10.61 +/- 1.41 MPa; 7 days: 6.94 +/- 1.40 MPa) (P <.001). SEM examination of the debonded metal and enamel surfaces showed mixed (adhesive and cohesive) failures for all groups. CONCLUSION Tin-plating a noble alloy produced the highest bond strength to enamel. Storing the tin-plated noble alloy in 37 degrees C distilled water for 48 hours before cementation did not result in a change in TBS. Using an Alloy Primer with a noble alloy resulted in statistically significant lower TBS than tin-plating.

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.

The Use of a Diagnostic Matrix in the Management of the Severely Worn Dentition

The management of the interim phase of a complete oral rehabilitation in patients with severely worn dentition is often challenging due to loss of occlusal vertical dimension, loss of tooth structure, uneven wear of teeth creating an uneven plane of occlusion, and para-functional habits. This paper will demonstrate how a clear thermo-forming matrix fabricated from the diagnostic wax-up can be used as a guide to facilitate treatment.