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Biomedical subjects

P P Demetriou

Publications and source records attributed to P P Demetriou.

14 recordsLinked to original sources
PubMed1991

Repairs with visible light-curing denture base materials.

Visible light-curing interpenetrating networks are newly developed materials suitable for several dental applications. These materials have several advantages, including versatility and good physicomechanical properties, but also present some weaknesses, such as increased water sorption and poor adhesion to plastic teeth. The suitability of a visible light-curing resin as a repair material, ie, its bending strength, was examined. Results were compared to those obtained with a self-curing acrylic resin. The visible light-curing resin led to repairs with lower strength.

Acrylic Resins↗
PubMed1987

Dimensional stability of dentures processed in boilable acrylic resins: a comparative study.

An investigation was conducted to evaluate and compare the dimensional stability of three fast boilable denture resins with a conventional and a high-impact denture resin processed with a long-curing cycle. Although the boilable denture resins have been introduced to the dental profession and offer merits such as faster processing, saving time for the dentist, patient, and technician, reduction of energy costs, and dramatic increase in denture laboratory production without adding personnel or purchasing new equipment, the relevant dental literature is sparse. The results of this investigation indicate that all five denture resins produced dentures that shrink. Also measurements between certain teeth showed shrinkages. Linear shrinkages of denture bases and teeth distances were less than 1%. Flange-to-flange and molar-to-molar changes were less than 0.5 mm and 0.2 mm respectively. Maxillary complete dentures processed in boilable resins presented less distortion in the midpalatal area across the posterior section than dentures processed in the conventional heat-cured resin. Although linear changes reported in this investigation were thought to be clinically insignificant, clinical studies should be conducted to establish correlation with laboratory findings.

Acrylic Resins↗
PubMed1986

Dimensional accuracy of duplicate dentures prepared by different methods.

The production of a duplicate denture demands a high degree of perfection to maintain dimensional accuracy of the duplicate denture. Duplicate dentures were made by four methods in order to investigate the dimensional accuracy in relation to a master denture. Replicas made from modeling wax (all-wax replica or acrylic resin base-wax teeth replica) demonstrated better dimensional accuracy compared with the all-acrylic resin replicas. It is well known that modeling wax used alone as a temporary denture base is an unsatisfactory material. The inherent shortcomings of the material may be overcome if dentists and patients make their assessment of the duplicate as quickly as possible in the mouth. The other alternative may be the production of a duplicate denture with an acrylic resin base and modeling wax teeth.

Acrylic Resins↗
PubMedDate not supplied

Color changes of denture base materials after disinfection and sterilization immersion.

This study evaluated the effects of chemical disinfectants on the color of denture base materials. Materials tested included Paladon 65 (Kulzer, Friedrichdorf, Germany), Triad VLC (Dentsply Int, York, PA), and ProBase Cold (Ivoclar, Schaan, Liechtenstein). The disinfectants were Klinex (Lever Hellas, Athens, Greece), Cidex-7 (Johnson & Johnson, East Windsor, NJ), Hibitane (Imperial Chemical, Macclesfield, UK), and Cabadol (Detax Karl Huber, Ettlingen, Germany). Denture material samples were placed in the various disinfectants and evaluated for color changes (delta E*) at intervals of 10 minutes, 10 hours, and 7 days. Changes in color were measured using a tristimulus colorimeter on 10 samples for each denture material and disinfectant combination. It was concluded that if the recommended disinfecting times are followed, no observable color changes should be anticipated for the denture materials tested. Even the long-term (7-day) immersion caused observable color changes only with Cabadol, a phenol-based disinfectant, and ProBase and Triad denture materials.

Acrylic Resins↗