A. Ben-Amar

The effect of porcelain color on the hardness of luting composite resin cement

Visible light- and dual-curing composite resin luting cements were cured under porcelain disks of different colors to examine the effect of porcelain color on surface hardness. Knoop microhardness measurements were made at exposure times of 48, 72, and 120 seconds. Higher levels of hardness were obtained with dual-cured resin. Visible light-cured resin irradiated through colored porcelain required more prolonged exposure times to reach a degree of hardness approaching that of dual-cure resin. From the standpoint of microhardness, dual-cured composite resin is preferred for luting porcelain restorations of > or = 2 mm thickness.

Comparison of microleakage for three one-bottle and three multiple-step dentin bonding agents.

PURPOSE This in vitro study compared the ability of several recently introduced 1-bottle adhesives to their preceding multiple-step dentin bonding agents in reducing microleakage around Class V composite restorations. MATERIAL AND METHODS Facial and lingual Class V cavities were prepared in 48 molar teeth, which were randomly divided into 6 equal groups. Three groups used the fourth-generation multiple-step systems, and 3 used the fifth-generation single-bottle adhesives. All cavities were restored by composite and subjected to thermocycling and intermittent occlusal loading. After immersion in 0.5% basic fuchsin, the teeth were cut faciolingually in 5 consecutive sections and evaluated for dye penetration using a binocular stereomicroscope. RESULTS There was no statistically significant difference in the degree of microleakage comparing the adhesives generation and manufacturer and the location of the cavity margins. A significant interaction was found between margin location and manufacturer, which implied that the sealing capacity at the enamel and cementum margins was material-specific. CONCLUSION Scotchbond Multi-Purpose and Single Bond adhesives provided the best seal for enamel margins, and One-Step and Optibond FL adhesives were best for cementum margins.

The control of marginal microleakage in amalgam restorations using a dentin adhesive: a pilot study.

Abstract A pilot study showed that marginal microleakage in fresh amalgam restorations was eliminated at both the enamel and dentin/cementum margins of Class V restorations in an in vitro study using Scotchbond Dental Adhesive applications to the cavity margins prior to the condensation of a spherical high-copper amalgam alloy.

Marginal microleakage: the effect of the number of cavity-varnish layers and the type of amalgam used

Abstract Microleakage of Class V amalgam restorations was studied, using 3 different types of alloy and varying numbers of application of cavity varnish. Significantly less microleakage was recorded by applying 2 layers of cavity varnish and using Tytin or Silmet amalgam alloys. Permite C alloy showed no statistical difference irrespective of the number of varnish applications.

Retention of prefabricated posts with dental adhesive and composite

Sixty-three No. 4 Dentatus threaded posts were cemented in extracted teeth and tested for tensile strength. The cementing medium was Silar composite alone or in combination with a conventional bonding agent or Scotchbond dental adhesive, or both. Results indicate that: Retention was greater when the posts were cemented with the Silar composite preceded with the application of Scotchbond. Retention was less with Silar composite alone or combined with a conventional bonding agent. Scotchbond is suggested for use as a bonding agent when cementing Dentatus posts with composites.

Cavity design for class II composite restorations.

Preparation design for posterior composite restorations should differ from that for amalgam restorations in the following manner. Occlusal form should be narrower and the depth shallower. The proximal extensions (facial and lingual) should be placed in areas that can be seen, probed, and polished. Internal line angles should be rounded and retenive grooves placed in proximal line angles (axiofacial and axiolingual) and the gingival wall. Beveling is recommended for proximal margins but not for occlusal margins.

Retention of dowels using Conclude composite resin as a luting medium.

Abstract The retention of Dentatus dowel posts in extracted teeth was examined for tensile strength. The Dentatus posts were cemented with “Conclude” luting cement alone or following two applications of Scotchbond Dental Adhesive. Dentatus dowel pins of different diameters were used although the canals were all prepared to the same diameter. The diameter of the dowel post has no significant influence on the retention. The application of Scotchbond to the walks of the root canal significantly increased retention of the posts.

Effect of water spray on lining materials and their adhesion to composite and dentin cavity walls.

The effect of an air-water spray on the adhesion of lining materials to both overlying composite restorations and cavity walls was evaluated. An in vitro study was performed on extracted molar teeth: Two resinous light-cured liners and one calcium hydroxide, chemically activated liner were compared. Teeth were restored with composite materials and subjected to cyclic thermal changes so that microleakage could be evaluated. Results indicated that adaptation between the restorative material and the liner was effective, regardless of whether the oxygen-inhibited layer was removed by being rinsed. A definite gap was detected between the liners tested and the dentin cavity walls.

The effect of burnishing on the marginal leakage of high copper amalgam restorations: an in vitro study

Abstract This article deals with the pros and cons of burnishing amalgam restorations. An in vitro study of Class V restorations tested 2 types of high copper amalgams: admixed (Silmet) and spherical (Tytin), and 3 combinations of pre- and post-carving burnishing procedures. The Admix amalgam showed less marginal leakage after burnishing procedures (pre-carved, and pre- and post-carved combinations), while with the spherical amalgam, no significant statistical difference was noted getween burnished and unburnished restorations. The best marginal adaptation was obtained with the admixed amalgam, in which burnishing was carried out both before and after the carving procedure.

The photocure attachment lens: its effect on polymerization of visible-light-cure resin composite

The attachment lens for a light-curing unit which disperses light over a larger area was investigated. The effect of polymerization on a composite material was compared with that obtained with a regular light-cured tip. It was found that for similar exposure times, the efficiency of curing was significantly reduced when this lens was used.