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Biomedical subjects

R Liberman

Publications and source records attributed to R Liberman.

At least 37 records · Page 2Linked to original sources
PubMed1990

Effect of retention grooves on tooth-denture base bond.

The bond strength of acrylic resin teeth with and without retention grooves processed onto standard and high-impact denture base resin was investigated. A shear compressive force was applied at an angle of 130 degrees to the lingual surface of the teeth until fracture occurred. The values were subjected to a two-way analysis of variance with repeated measures. Canine teeth bonded better than central or lateral incisors (p less than 0.01). A significantly greater force was required to fracture teeth from high-impact resin (p less than 0.01). Vertical retention grooves enhanced bond strength (p less than 0.01).

Acrylic Resins↗
PubMed1990

A combined amalgam and composite resin restoration.

Difficulties with restoring class II cavities with posterior composite resin are enumerated. The problem is especially acute when a gingival margin lies close to or apical to the cementoenamel junction. A technique is described whereby the proximal portion of class II cavities is restored with amalgam to the contact area and composite resin inserted in the remainder of the cavity. Microleakage was studied by dye penetration tests. At the composite resin/cementum interface microleakage was significantly greater than at the amalgam/cementum and amalgam/composite resin interfaces (p less than 0.001). No statistically significant difference was observed in microleakage between the amalgam/cementum and amalgam/composite resin interfaces.

Bicuspid↗
PubMed1990

Long-term use of dentine adhesive as an interfacial sealer under Class II amalgam restorations.

An in vitro study was carried out to evaluate the long-term sealing properties of a light-cured dentine adhesive in Class II amalgam restorations. The restorations were subjected to repeated vertical occlusal loads and a number of thermocycling procedures. The results demonstrated significant advantages of using a dentine adhesive as an interfacial sealer in order to reduce microleakage, compared to a conventional Copal varnish.

Composite Resins↗
PubMed1990

The effect of posterior composite restorations on the resistance of cavity walls to vertically applied occlusal loads.

The resistance of the cavity walls of non-vital premolars to vertically applied occlusal forces was studied. Standardized MOD cavities were prepared, restored, and vertical forces were applied to each of the cuspal tips by the Instron machine. Results suggest that bevelled etched-enamel margins and dentine-bonded posterior composite resin restorations significantly improved (by 33%) the resistance of the remaining cavity walls compared to amalgam restorations. In a control group, in which no restorations were carried out in the prepared cavities, the resistance of the walls was significantly smaller than in both restored groups.

Bicuspid↗
PubMed1989

Long-term sealing properties of amalgam restorations: an in vitro study.

Conventional and high-copper Class V amalgam restorations showed leakage after seven months' storage in artificial saliva and thermal-stressing. The rate of marginal microleakage was not significantly affected by the application of a Copal varnish after this period. At the 14-month storage and thermal-stressing period, all varnished and unvarnished high-copper restorations and the varnished conventional amalgam restorations showed significantly improved sealing properties in the occlusal wall compared with the seven-month period. The unvarnished conventional amalgam restorations appeared to have reached their peak sealing level by seven months under the conditions of this experiment. No significant improvement in the sealing properties of either the conventional or high-copper amalgam restorations was achieved after the 14-month period by the application of Copal varnish.

Copper↗
PubMed1989

Joint strength between two layers of different amalgam types condensed successively.

The flexure strength of the joint between layers of different types of amalgam condensed consecutively one on to the other was evaluated in vitro. The data indicated no statistical differences in flexure strength between the combined samples (single composition spherical and lathe-cut eutectic amalgams) and the control (homogeneous lathe-cut eutectic amalgam).

Dental Alloys↗
PubMed1989

Conditioning of root canals prior to dowel cementation with composite luting cement and two dentine adhesive systems.

Two hundred and forty root canals of extracted single-rooted teeth were prepared to the same dimension, and Dentatus posts of equal size were cemented without screwing them into the dentine. Five cleansing solutions and two dentine adhesive systems were evaluated prior to post-cementation using chemical-cure composite resin. 'Pull-out' tests were then conducted in order to evaluate the bond strength of these intra-pulpal posts. The use of Conclude (composite luting cement) alone, with or without the cleansing solutions, resulted in significantly lower pull-out forces. Scotchbond Dental Adhesive gave significantly better results, regardless of the cleansing solution used. Gluma Dentine Adhesive significantly increased the pull-out forces only when used with its supplied cleanser or Tubulicid.

Acrylates↗
PubMed1989

The effect of ultrasonic cleaning and air polishing on the marginal integrity of radicular amalgam and composite resin restorations. An in vitro study.

This study attempts to put at ease some uncertainty of a possible damaging effect of ultrasonic scaling and air polishing procedures on dental restorations (amalgam and composite resin). Under optimal in vitro conditions, the margins of 120 restorations were subject to thorough ultrasonic and air polishing instrumentation in order to mimic those extensively used in periodontal treatments. Light-cure composite resin and Dispersalloy amalgam alloy were used to restore class V cavities at the CEJ. After being exposed to ultrasonic scaling and air polishing, cleaning, and thermocycling, clinical evaluation of the cavity margins and microleakage examination showed no detrimental effects of these procedures.

Air↗
PubMed1988

Clinical use of extracorporeal membrane oxygenation in the treatment of persistent pulmonary hypertension following surgical repair of congenital diaphragmatic hernia.

The clinical use of extracorporeal membrane oxygenation (ECMO) in the treatment of persistent pulmonary hypertension following surgical repair of congenital diaphragmatic hernia is reported on 11 patients. The patients had a total of 13 treatments; two patients had two treatments. During the same period of clinical use, 122 patients were placed on ECMO for all causes. The indications, results, and complications of the use of ECMO for treatment following surgical repair of congenital diaphragmatic hernia are presented. The reversal of persistent pulmonary hypertension is demonstrated. All patients treated by ECMO for congenital diaphragmatic hernia have survived.

Extracorporeal Membrane Oxygenation↗
PubMed1988

The effect of retention grooves on gingival marginal leakage in Class II posterior composite resin restorations.

In this laboratory study, the effect of retention grooves in the proximal portion of class II cavities on the marginal microleakage using light-cured composite resin was examined. The retention grooves were placed at the axio-facial and axio-lingual line angles and in the gingival floor of the cavities. The teeth were restored with Herculite composite resin with etching and dentine bonding and polymerized in two different ways: (i) a single mass of restorative material was polymerized all at once; and (ii) incrementally placed amounts of restorative material were each polymerized separately until the cavity was completely filled. Marginal microleakage was evaluated by the degree of dye penetration at the gingival margin of the restorations after suitable thermocycling procedures. It was concluded that marginal microleakage was significantly reduced when the composite resin was placed and polymerized incrementally, and that no advantage was gained from retention grooves with this incremental technique. However, when polymerizing in one single mass of material, retention grooves were found to be necessary in order to reduce marginal microleakage at the gingival wall.

Acid Etching, Dental↗