Quintessence International, 11/1994

Two hundred twenty permanent young molars in 60 children aged 8 to 13 years received only one application of a light-activated resinous sealant. The retention rate was assessed 6 and 12 months later. The teeth were divided into 2 groups of 110 each. In one of the groups the pits and fissures were etched with 37% phosphoric acid before being sealed (group 1); in the other (group 2) these areas were etched with 10% maleic acid. The retention rate of group 1 was 98.4% at 6 months, and 96.8% at 12 months. Group 2 had retention rates of 97.5% at 6 months and 95% at 12 months. There was no statistically significant differenc e between the two groups in the two test periods, nor were there differences in the same group at the different periods.

In the construction of a removable partial denture, the patient's interest frequently lies in the improvement of his or her esthetic appearance. This desire can be underestimated by the scientifically trained dentist, resulting in a disappointed patient. The perimeters of potential esthetic improvement might be influenced by the limitations of each individual case. However, appropriate care in the selection, arrangment, and position of teeth can overcome some of the limitations. This article describes the benefits of a well-planned, systematic approach to selection of the framework design, porcelain shade, and tooth mold as well as the base finish, and it illustrates, with specific examples, how to achieve the maximum esthetics in removable partial denture prosthodontic

This article considers the logistrical problems involved when the check (interocclusal) record procedure is used to remount complete dentures on an articulator. It reports the development of upper and lower check record mounting blocks that may be made to fit any articulator, thus enabling the procedure to be performed easily and quickly at chairside.

The wear of composite resin is influenced by the presence of microcracks on its surface. Recently, it has been shown that surface-penetrating sealants are effective in reducing the wear of posterior composite resin by sealing these defects. The purpose of this study was to investigate the effects of one of these sealants on the wear of various luting agents in conjunction with composite resin inlays. The specimens were subjected to a three-body wear test for 400,000 cycles. The wear values of both composite resin and luting agents were determined by profilometric trcings to the nearest 2 um. There were no statistically significant differences between the treated and untreated groups as it related to the wear of the luting agents. The wear values of composite resin inlays treated with the sealant, however, were significantly lower than those wihtout treatment, regardless of the type of luting agent used for cementation.

Scanning electron microscopy was used to compare the marginal gaps of restorations milled by machinable ceramic systems to the marginal gaps of conventional laboratory-sintered ceramic restorations. For occlusal surfaces, the average marginal gap was 80 um for both laborato ry- and Celay-produced inlays. The mean gap was 200 um and 170 um, respectively, for Cerec T (turbine motor) and Cerec EM (electric motor) inlays. For approximal boxes, the average marginal gap was 100 um for inlays produced with conventional laboratory-sintering techniques, 80 um for Celay restorations, and 280 um for the Cerec T restorations, and 260 um for Cerec EM-machined inlays. The ceramics used, as well as the different systems themselves, can influence the results and the clinical outcome of the restorations.

The aim of this in vitro study was to evaluate four methods of reducing the marginal microleakage of directly placed Class II composite resin restorations. Mesio-occlusal and disto-occlusal preparations with all margins confined to enamel were placed in extracted human molars. The teeth were restored with one of four techniques using multi-incremental placement, stored for 24 hours in 37 degrees C water, thermocycled, and placed in a dye solution. The teeth were sectioned in a mesiodistal direction through the restoration and evaluated for microleakage at the gingival margins. Restorations placed in conjunction with an enamel bonding agent demonstrated severe microleakage. Marginal microleakage was reduced by the use of an extended base of visible light-cured glass-ionomer cement, A BondAband, or a dentinal bonding agent.

Sulfur compounds found in latex gloves may be deposited on teeth and ginvia, inhibiting the setting of poly(vinylsiloxane) impression materials. The objective of this in vivo study was to screen a variety of methods to remove these contaminants. Ten patients were each tested with eight decontamination methods. Before each trial, the facial surfaces and adjacent gingiva of the maxillary central and lateral incisors were contaminated with 20 wipes of a latex glove. Decontamination methods included a 30-second rinse with mouthwash, 3% hydrogen peroxide, or air-water syringe; a 30-second toothbursh scrub with water, mouthwash, or hydrogen peroxide; a 30-second cotton pellet-Davidry scrub; and a 30-second cleaning with a prophy cup and pumice. A 10-second water rinse followed each method except the air-water syringe and Cavidry groups. A low-fiscosity poly(vinylsiloxane) impression material was then used to take an impression of the area. To test surface inhibition, teh gingival, tooth, and palatal impression surfaces were wiped with cotton-tipped applicators, and the degree of inhibition was subjectively categorized by two independent investigators. Mechanical decontamination with a toothbrush or pumice was significantly more effective than was rinsing alone, regardless of the solution used.

Contemporary, third-generation dentinal bonding products have become highly specialized in producing high bond strengths to dentin. This investigation compared in vitro bond strengths of six dentinal bonding systems and their matched composite resins to human enamel and dentin. The effects of treatment by dentinal primers on enamel bond strengths as well as the effects of phosphoric acid on the strengths of dentinal bonds were measured. The use of dentinal primer on enamel improved the bond strengths of Prisma Universal Bond 3/Prisma APH and XR Bond/Herculite systems and had no effect on Denthesive/Charisma, Scotchbond 2/Silux, and Tenure/Perfection, while the enamel bo nd strengths of Gluma/Pekalux declined. Pretreatment of dentin with phosphoric acid improved the bond strengths of Denthesive/Charisma, Prisma Universal Bond 3/Prisma APH and XR Bond/Herculite, but had no effect on Gluma/Pekalux, Scotchbond 2/Silux and Tenure/Perfection.

Treatment of dentin with acids results in a surface change that is potentially useful for mechanical retention of resins in tooth structure. This study examined the effect of etching of dentin on the seal of cavities restored with composite resin. Eighty cavities, each measuring 2.0 mm in diameter and 1.5 mm in depth, were prpared in dentin of extrac ted human teeth and randomly assigned to two equal groups. The experimental group was etched with 37% phosphoric acid for 15 seconds before restoration. The control specimens were similarly restored but without any etch ing of dentin. After the specimens were thermocycled, the seal of each cavity was assessed by measurement of the gap between the restorative material and the tooth structure. The experimental group registered significantly better adpatation to the cavities than did the control group.