Χημική δομή και μεσοφασικές δράσεις τεσσάρων σιλανιούχων σκευασμάτων επιδιόρθωσης κεραμικών όψεων

The experimental part of this study was performed in co-operation with the Quality Control Section of the Research Center for Biomaterials, Athens Greece. Acrylic, composite or porcelain veneering of dental alloys has been for many years the choice for esthetic prosthetic restorations. Despite the development of improved materials, veneer fractures or delamination is still a clinical problem.During the last decade silanes were introduced as the most effective coupling agents for the chairside repair of failed porcelain and acrylic veneers. Most of the studies performed on silanes as repair materials have been focused on the interfacial strength of composite resin repairs on porcelain alloys. However, the obtained results are contradictory to support the efficiency of specific products. Besides, the bond strength studies alone can not establish the existance of chemical bonding at the interface, since they are influenced by a great number of variables. Also, thereaction mechanism can not be predicted if the detailed composition of the products is unknown. The purpose of this study was : a) to investigate the chemical composition of a series of representative silane products for porcelain repair. b) to evaluate the interfacial topography and integrity of the interfaces between silane treated porcelain alloys, repaired with composite resins.c) to assess the effect of the type of the metal substrate on the activity of the silane primer.The silane products used in the study were two prehydrolyzed (Kerr Ceramic Primer, Scotchprime) and two of immediate hydrolyzation (Enamelite 500, Silanit). These silane primers were tested on three representative types of porcelain alloys, an Au-Pt (Argen 8), a Hi-Pd (Argipal) and a Ni-Cr (T3). The analytical methodology included : I) determination of the composition of the silanes utilizing Ή-ΡΓ NMR spectroscopy on a 400 MHz instrument. II) assessement of the activity of silanol -OH groups in the prehydrolyzed materials by Ή-ΡΓ NMR and the D2 0 technique. III) scanning electron microscopy and electron probe microanalysis of the alloy-composite and porcelain-composite repaired interfaces, with intermediate silane layers. IV) x-ray photelectron spectroscopic (ESCA) investigation of the alloys treated with a thin silane layer from each silane product. The ESCA analyses were conducted on a small area mode. Depth profiling was performed to investigate the uppermost 20 Â layer at 10 Â intervals. According to the results obtained from the study:- all the silane products contain the same active substance γ-methacryloxypropyltrimethoxysilanol for the prehydrolyzed and γ-methacryloxypropyltrimetfhoxysilane for the immediately hydrolyzed.- the concentration of the active silanol for the prehydrolyzed silanes was found 0.88% for Kerr Ceramic Primer and 5.09% for Scotchprime. - the dilutors were ethanol (Kerr Ceramic Primer, Scotchprime) and isopropanol (Enamelilte 500, Silanit). - scotchprime and Enamelite 500 contain additionally acetic acid while Enamelite 500 also contains a Bis-GMA resin. - the prehydrolyzed products have active -OH groups for adsorption. - an improved transitional zone was detected at the alloy-composite and porcelaincomposite interface treated with Enamelite 500, Kerr Ceramic Primer and Silanit, compared to the control where no silane was used. - the orientation of the silanol groups towards the alloy surface was enhanced in the Hi-Pd and especially in the Ni-Cr alloy, indicating greater bonding potential of the silane primers with these alloys.

Grantor dc:publisher

National and Kapodistrian University of Athens

Year dc:date

1990

Authors dc:creator

• Anagnostopoulos, Theodoros
• Αναγνωστόπουλος, Θεόδωρος

• Επιδιόρθωση κεραμικών επικαλύψεων
• Επιδιόρθωση προσθετικών αποκαταστάσεων
• Μεσοφασικές δράσεις σιλανίων
• Σιλάνια
• Χημική δομή σιλανίων
• Chemical composition of silanes
• Interfacial structure of silanes
• Porcelain primers
• Repair of prosthetic restorations
• Silanes
• Ιατρική και Επιστήμες Υγείας
• Κλινική Ιατρική
• Medical and Health Sciences
• Clinical Medicine

Language dc:language

gre

Identifier

10.12681/eadd/1273

OAI identifier oai:identifier

oai:10442/1273